Page 1 of 2 12 LastLast
Results 1 to 100 of 122
  1. #1
    mtbr member
    Reputation: scottg07's Avatar
    Join Date
    Jun 2006
    Posts
    348

    crank lengths 175 vs 170

    how many of you ride 170 vs 175 mm crank lengths? my new holzfellers are gonna be 170,should i have gotten 175? what is the benefit/difference between the two. obviously the 175 is longer and ur going to have more torque at your peak pedal but really how much difference does it make/feel??

  2. #2
    mtbr member
    Reputation:
    Join Date
    Jul 2008
    Posts
    1,295
    Since it's for AM, I'd go with the shorter ones. Unless you're going to be climbing a lot, and I mean A LOT, you should get the 170 one. With the longer crank-arms, you could even hit rocks and logs, since they'd be closer to the ground.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Apr 2008
    Posts
    408
    Torque=radius x force. 5mm increase from 170 to 175mm is equal to a 3% increase in torque by choosing the longer crankarm (considering force is constant). It's likely not a significant gain to sacrifice better ground and rock clearance. I'd go with the 170mm for AM riding.
    Remember, you are unique, just like everyone else.

  4. #4
    the WALKING DEAD
    Reputation:
    Join Date
    Jun 2006
    Posts
    229
    I can't tell the difference. I have 170 and 175 on my different bikes and can't tell what I'm riding on the trail. If you look at 5mm on a ruler, it is basically nothing. I don't understanad why it is such a big deal. They feel the same. If you didn't know ahead of time, you wouldn't know what you were on.
    Your momma's so nasty, she keeps ice between her legs just to keep the crabs fresh.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Dec 2004
    Posts
    787

    shortys

    I switched to 170, partly due to a desire for exploration, partly because I got an 07 Superlight with a fairly low bottom bracket.

    I feel a pretty big difference switching between the two lengths. I generally like the 170s better all around, but there is no doubt that I don't have quite the same level of torque/power at the upper limit. The upside is that my knees are happier; I shift a little more rather than try to grunt/mash my way through stuff. I think I "spin" a little more smoothly at "normal" RPMs too.

    Bear in mind that I am relatively short-legged (30" pant inseam on 6'1") so long leggers might not feel the same way.

    The good side of the 170s I hadn't thought of before trying it is that it is easier shifting weight from one outside pedal to the other when carving turns, and even cooler, when pedals are level, my feet are a little closer together, allowing me to bend my knees a little better and/or keep my body/shoulders more square to the bike. All in all, it was sorta similar to the effect when I relented and dropped my seat an inch or so down from "optimal" cross country height. Better handling all around at the expense of a little bit of ultimate performance.

  6. #6
    mtbr member
    Reputation: Lumbee1's Avatar
    Join Date
    Dec 2004
    Posts
    1,908
    175 to 170 to 180.

    The 175's were fine for the type of riding I do. While trying to remove the crankset, the LBS found a manufacturing defect. The crankset got destroyed in the process and was replaced with 170mm crankset. I couldn't feel an immediate change in crankarm length but all forms of riding now required lots spinning... lots and lots of spinning. Log crossings and some of the more technical obstacles became more difficult while straight line riding seemed easier with lots of spinning of course. The LBS could not find a replacement 175 in time and offered to upgrade me to 180's. I am 6'2" and gladly jumped on the opportunity. Once again, it wasn't an immediate difference. I could not spin the 180's as smoothly as the 175's and certainly not the 170's but log crossing, difficult climbs, and technical obstacles seemed much easier. I eventually learned to spin better on the 180's but even after a year and a half, I am still not a smooth as I was on the 170's.

    If I had to do it all over again, I would pick the 180mm crankset again. For around town or cyclocross, 170 or 175 would be best.

  7. #7
    mtbr member
    Reputation: Gman086's Avatar
    Join Date
    Jul 2004
    Posts
    4,410
    Delete
    Last edited by Gman086; 05-07-2018 at 11:31 PM.
    "There's two shuttles, one to the top and one to the hospital" I LOVE this place!!!

  8. #8
    meow, meow.
    Reputation: J. Random Psycho's Avatar
    Join Date
    Apr 2008
    Posts
    2,465
    I went from the usual 175 to 170 for 3 reasons:

    1. The transition from HT to FS. I wanted the ground clearance, and I got it.
    2. I'm average height but slightly less-than-average leg length. I wanted to try out how it would feel with shorter cranks.
    3. I prefer to spin.

    Of all these reasons I find #1 the most important one in making a decision, but it's not that much significant as I thought it to be. I'd say go with 175 mm.

    That said, I thank myself for going to a 170 mm XTR crankset every time I clip something on the ground. )

  9. #9
    mtbr member
    Reputation: Lumbee1's Avatar
    Join Date
    Dec 2004
    Posts
    1,908
    IMO, ground clearance should not be a deciding factor. 5mm per crank arm is less than 1/4 of an inch (.1968" or 3/16").

  10. #10
    mtbr member
    Reputation: scottg07's Avatar
    Join Date
    Jun 2006
    Posts
    348
    well so what should be then?

  11. #11
    Dirt Deviant
    Reputation: savagemann's Avatar
    Join Date
    Jan 2008
    Posts
    3,693
    How tall are you? Whats your imseam? What kind of bike do you ride and what size is it?
    Look, whatever happens, don't fight the mountain.

  12. #12
    mtbr member
    Reputation: scottg07's Avatar
    Join Date
    Jun 2006
    Posts
    348
    about 6 ft tall, 30 to 32 inch inseam, ride a large transition vagrant

  13. #13
    meow, meow.
    Reputation: J. Random Psycho's Avatar
    Join Date
    Apr 2008
    Posts
    2,465
    Then 175 mm would suit you better than 170 mm. That according to the established views, anyway ).

    In other words, if I was 6 feet tall, I would have stayed away from 170 mm on a MTB.

  14. #14
    mtbr member
    Reputation: jetta_mike's Avatar
    Join Date
    Feb 2007
    Posts
    484
    5'8" and a 33" inseam here. I have never thought of getting 170's.
    Last edited by jetta_mike; 02-08-2009 at 07:53 PM.

  15. #15
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,492
    Quote Originally Posted by savagemann
    How tall are you? Whats your imseam?
    Thank you! I can't believe there were 10 posts of nonsense before someone bothered to ask this question. It's like giving advice on pant size without asking how big someone's waist is. Yes, crank length is personal preference, but your leg size plays a big part in this.

    OP: with a 30" inseam you could probably go either way. At 32" I'd say you want 175's. I'd try them and see what you think.

    It's not just about the torque, it's about the position it puts your legs and knees in.

  16. #16
    meow, meow.
    Reputation: J. Random Psycho's Avatar
    Join Date
    Apr 2008
    Posts
    2,465
    Quote Originally Posted by kapusta
    Thank you! I can't believe there were 10 posts of nonsense before someone bothered to ask this question. It's like giving advice on pant size without asking how big someone's waist is. Yes, crank length is personal preference, but your leg size plays a big part in this.
    But notice that the OP has only asked about 2 length options, and not extremely disparate ones. This can be understood as a leg size hint...

    You see, I am used to creating heuristic algorithms that have to yield satisfactory results given incomplete data. I am also used to having a go at tasks that are poorly formulated, with no way to quickly obtain a more deterministic specification and a requirement that software must be created like, "yesterday" (or an answer given right away, for that matter). )

    This routine, when reiterated over and over again, creates certain specialized workflow patterns, it seems. Patterns that are not easy to intercept and override before the pattern manager autonomously recognizes a task and engages a pattern to try and solve it. That must be mental reflexes in action. )
    26" rigid SS 4130 BB7 nylon-flats ESI latex-tubes non-lubricated-8spd

  17. #17
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,492
    Quote Originally Posted by J. Random Psycho
    But notice that the OP has only asked about 2 length options, and not extremely disparate ones. This can be understood as a leg size hint...

    You see, I am used to creating heuristic algorithms that have to yield satisfactory results given incomplete data. I am also used to having a go at tasks that are poorly formulated, with no way to quickly obtain a more deterministic specification and a requirement that software must be created like, "yesterday" (or an answer given right away, for that matter). )

    This routine, when reiterated over and over again, creates certain specialized workflow patterns, it seems. Patterns that are not easy to intercept and override before the pattern manager autonomously recognizes a task and engages a pattern to try and solve it. That must be mental reflexes in action. )
    Shows you how little I know. I thought you were guessing.

  18. #18
    ride hard take risks
    Reputation: dogonfr's Avatar
    Join Date
    Jan 2005
    Posts
    25,412
    I would just take the reciprocating mass divide then by the counteracting flow of suspension then multiply that by the pushingus factor which then gets deposited into the holder by the huffinupagainst flat function and go with the 170's.
    Formotion Products
    http://www.formot

  19. #19
    TNC
    TNC is offline
    noMAD man
    Reputation: TNC's Avatar
    Join Date
    Jan 2004
    Posts
    12,059
    There is no "one" answer to this. People making blanket statements are only stating what works for them. Generally riders fall into power-pedaler or spinner categories...generally. If one is a strong pedaler, one can generally benefit from longer cranks. But...you also have to consider the weight of the bike...the ground clearance...the rider physiology like leg length or even leg strength or injury...the terrain ridden...etc...etc. I'm 6 feet tall with a 32" inseam. I use 170mm cranks for my AM bikes. I'm also 57 years old with 57 year old knees, and I do spin instead of mash. The suggestion that 170mm cranks are only for DH bikes is ridiculous. Most people have just been programmed with the idea that 175mm cranks are the proper "normal". Other riders' needs and conditions may vary.

  20. #20
    offroader
    Reputation:
    Join Date
    Dec 2008
    Posts
    2,190
    The difference between 175 and 170 was a FREE crankset. Since I ordered a 175 and they sent me a 170.

  21. #21
    meow, meow.
    Reputation: J. Random Psycho's Avatar
    Join Date
    Apr 2008
    Posts
    2,465
    Guilty as charged, I'm a geek.

    kapusta, why yes, I was doing just that: guessing. That's what heuristics is about. Finding the least wild guess of all conceivable wild guesses. )

    But take a look at what TNC just said. Namely, that there are sooo damn many things to consider (and what's worse - their effects differ in every case). I think that it just isn't worth doing that in a methodical way unless you're looking at some unusual crank lengths and unusual sized guy.

    Also notice how I didn't outright suggest the 175 mm length but first proceeded to give an example of how such a difference works, as perceived by an average built person.

    The question remains, however, just how did the 175 mm became so much of a standard? Even if it is formulated in terms of us being programmed by the industry into the use of 175 mm cranks, it's still a question worth asking.

    I think that the answer to this is very much like the answer to many other bike design questions (like, why the spoked wheel, why the chain and cog transmission, why this wheel size for doing that, etc). Enter emergent algorithms... The bicycle as we know it is not a result of planned development. It is an ensemble of parts and practices that just... turn out... to play well together. No discernible authority is there to decide how an entire bike should look and work (even if some modern marketing strategies are trying to pull this off on us ). It's the generations of bikes that just keep proving themselves and selling themselves...
    26" rigid SS 4130 BB7 nylon-flats ESI latex-tubes non-lubricated-8spd

  22. #22
    mtbr member
    Reputation: markw1970's Avatar
    Join Date
    Oct 2007
    Posts
    527
    Have a read of this... http://www.sheldonbrown.com/cranks.html

    And for those too lazy to read it all... best quote "I think people really obsess too much about crank length. After all, we all use the same staircases, whether we have long or short legs. Short legged people acclimate their knees to a greater angle of flex to climb stairways, and can also handle proportionally longer cranks than taller people normally use."

  23. #23
    meow, meow.
    Reputation: J. Random Psycho's Avatar
    Join Date
    Apr 2008
    Posts
    2,465
    markw1970,
    yes, I have read that some years ago.

    But crank length is way more easier to tweak than staircases. ) Besides, whereas long legged people can just step over several small stairs at once, the short legged people are having hard time with tall stairs. That's why stair dimension standards have been emerging in building design throughout 20th century. Older buildings have much weirder and disparate stair sizes. Even older buildings have different height stairs within staircases...

    More users, more use cases, more feedback, and voila! Before long the host of opportunities (most of them meaningless) converges into a few viable options (most of them meaningful). Evolutionary development in action...
    26" rigid SS 4130 BB7 nylon-flats ESI latex-tubes non-lubricated-8spd

  24. #24
    ffwd
    Reputation:
    Join Date
    Dec 2006
    Posts
    42
    Put the 170's on and go ride. You probably won't notice the difference. I switched to 170's 2 years ago and started to climb better/stronger in fear of lost leverage.

  25. #25
    meow, meow.
    Reputation: J. Random Psycho's Avatar
    Join Date
    Apr 2008
    Posts
    2,465
    I do notice the difference... with the 170 mm, the gears seem a little off (from being used to 175). But that's not anything to worry about. However I think that with say 165 mm it would have been harder to adapt to.
    26" rigid SS 4130 BB7 nylon-flats ESI latex-tubes non-lubricated-8spd

  26. #26
    it's....
    Reputation: Strafer's Avatar
    Join Date
    Jun 2004
    Posts
    2,087
    you obviously need 172.5mm.

  27. #27
    mtbr member
    Reputation:
    Join Date
    Apr 2007
    Posts
    230
    Quote Originally Posted by kapusta
    Thank you! I can't believe there were 10 posts of nonsense before someone bothered to ask this question. It's like giving advice on pant size without asking how big someone's waist is. Yes, crank length is personal preference, but your leg size plays a big part in this.

    OP: with a 30" inseam you could probably go either way. At 32" I'd say you want 175's. I'd try them and see what you think.

    It's not just about the torque, it's about the position it puts your legs and knees in.
    Exactly!
    The size of the bike does matter, but if you over 6 ft, 175's are probably the best bet.

  28. #28
    mtbr member
    Reputation: HotzKiss's Avatar
    Join Date
    Jun 2004
    Posts
    199

  29. #29
    mtbr member
    Reputation: chas_martel's Avatar
    Join Date
    May 2006
    Posts
    3,476
    Quote Originally Posted by Strafer
    you obviously need 172.5mm.

    Who has 172.5 mm cranks?
    Nobody cares...........

  30. #30
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,492
    Quote Originally Posted by chas_martel
    Who has 172.5 mm cranks?
    I think some road cranks come in 2.5mm increments. At least some Shimanos did when I was shopping for them a few years ago.

  31. #31
    Its got what plants crave
    Reputation: Jim311's Avatar
    Join Date
    Feb 2006
    Posts
    5,934
    Don't overthink this, it isn't going to matter much anyway. I buy whichever is on closeout
    Ocala Mountain Bike Association - www.omba.org

  32. #32
    mtbr member
    Reputation:
    Join Date
    Jul 2008
    Posts
    89
    Quote Originally Posted by Aust95
    Torque=radius x force. 5mm increase from 170 to 175mm is equal to a 3% increase in torque by choosing the longer crankarm (considering force is constant). It's likely not a significant gain to sacrifice better ground and rock clearance. I'd go with the 170mm for AM riding.
    so a 3% decrease in torque is insignificant but a 3% decrease in ground clearance is?

  33. #33
    mtbr member
    Reputation: biketuna's Avatar
    Join Date
    Mar 2008
    Posts
    472
    I'm 5'6" and use 170mm on all my bikes
    _______________
    1x10 IS SO FINE on my 21.9 lbs IBIS SL-R
    11-36 XTR in the rear, 36T wide-narrow upfront

  34. #34
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,492
    Quote Originally Posted by altezza2k2
    so a 3% decrease in torque is insignificant but a 3% decrease in ground clearance is?
    Apparently to him, yes.

  35. #35
    nnn
    nnn is offline
    mtbr member
    Reputation: nnn's Avatar
    Join Date
    Feb 2005
    Posts
    799
    I used to have really old Deore 170s, then switched to new-ish STX-RCs at 175 and mistook the extra stiffness for better leverage until I recently bought Race Face Turbine LPs at 170 (and we know those stinkers are stiFF) and to be honest the difference in torque really is ~3% ...ie nothing, and the pedal clearance is a welcome + I can spin slightly faster cadences than before.
    "Life begins at 140" Richard Burns
    http://www.nikolay-k.com

  36. #36
    mtbr member
    Reputation:
    Join Date
    Sep 2005
    Posts
    195
    I can spin faster on 170mm crank on my commuter. Spin slower on my FS bike but more power on 175mm. But I'm still slow no matter what crank size.

  37. #37
    Grinder
    Reputation: nogod's Avatar
    Join Date
    May 2009
    Posts
    339
    there are also 177mm cranks
    Quote Originally Posted by a stoned guy with a beer in his hand eyeballing your sisters bike
    "i fit my bike to fit me;not for looks...nice did you buy that bike from jc whitney?" Stoner Island 1984

  38. #38
    GAME ON!
    Reputation: saturnine's Avatar
    Join Date
    Mar 2007
    Posts
    4,964
    Quote Originally Posted by chas_martel
    Who has 172.5 mm cranks?
    xtr 970
    RIP Adam Yauch

    "M.C. for what I AM and do, the A is for Adam and the lyrics; true"

  39. #39
    offroader
    Reputation:
    Join Date
    Dec 2008
    Posts
    2,190
    Quote Originally Posted by heavyg
    I feel a pretty big difference switching between the two lengths. I generally like the 170s better all around, but there is no doubt that I don't have quite the same level of torque/power at the upper limit. The upside is that my knees are happier; I shift a little more rather than try to grunt/mash my way through stuff. I think I "spin" a little more smoothly at "normal" RPMs too.

    Bear in mind that I am relatively short-legged (30" pant inseam on 6'1") so long leggers might not feel the same way.

    The good side of the 170s I hadn't thought of before trying it is that it is easier shifting weight from one outside pedal to the other when carving turns, and even cooler, when pedals are level, my feet are a little closer together, allowing me to bend my knees a little better and/or keep my body/shoulders more square to the bike. All in all, it was sorta similar to the effect when I relented and dropped my seat an inch or so down from "optimal" cross country height. Better handling all around at the expense of a little bit of ultimate performance.
    I feel the same way about 170's. I spin better, my knees are happier, and it's easier shifting weight from one side to the other. I've got 170's on my 2 26" full susser's and 175's on my SS 29er and SS 26er. The 175's are easier to mash up hills.

  40. #40
    mtbr member
    Reputation: GnarBrahWyo's Avatar
    Join Date
    Jun 2012
    Posts
    2,827
    A 3% loss in torque can be immediately made up for choosing another gear. If you are mashing up a hill at a race you will use a gear to get you up the hill that gets you up the hill fast. A crank arm won't be the deciding factor. And yes, I just brought back to life this dead thread!

  41. #41
    meow, meow.
    Reputation: J. Random Psycho's Avatar
    Join Date
    Apr 2008
    Posts
    2,465
    But but I only have one gear..


    BTW I tested 165 mm cranks on SS recently (low BB so they had to run short cranks), with the gear chosen to get the needed gain ratio. It felt all wrong!
    26" rigid SS 4130 BB7 nylon-flats ESI latex-tubes non-lubricated-8spd

  42. #42
    mtbr member
    Reputation: GnarBrahWyo's Avatar
    Join Date
    Jun 2012
    Posts
    2,827
    Quote Originally Posted by J. Random Psycho View Post
    But but I only have one gear..


    BTW I tested 165 mm cranks on SS recently (low BB so they had to run short cranks), with the gear chosen to get the needed gain ratio. It felt all wrong!
    We're talkin' gears though.

  43. #43

  44. #44
    mtbr member
    Reputation: GDTRFB8's Avatar
    Join Date
    Jun 2017
    Posts
    8

  45. #45
    mtbr member
    Reputation: sml-2727's Avatar
    Join Date
    Nov 2013
    Posts
    1,618
    Has anyone ever looked at a ruler and see how little 5mm is?
    2018 Canyon Spectral
    2016 Ibis Ripley OG
    2016 Salsa Bucksaw

  46. #46
    always licking the glass
    Reputation: stripes's Avatar
    Join Date
    Sep 2016
    Posts
    1,336

    crank lengths 175 vs 170

    Quote Originally Posted by Gman086 View Post
    Save the shorter cranks for the downhill bikes. It's ridiculous to go short on an AM rig IMHO.

    Have FUN!

    G MAN
    Depends on the rider and how their measurements are. I ran the gear calculator and it said 163mm for me. This year I switched from 165mm to 160mm and I wonít go back. 160mm works well for me. Iím 5í4Ē and have a 29.5Ē inseam.
    Guerrilla Gravity BAMF, Colorado Front Range
    Writer, MTB4Her.

  47. #47
    mtbr member
    Reputation: ladljon's Avatar
    Join Date
    Nov 2011
    Posts
    299
    Lmao>>>
    Attached Thumbnails Attached Thumbnails crank lengths 175 vs 170-fullsizeoutput_540.jpg  


  48. #48
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    8,845
    Quote Originally Posted by ladljon View Post
    Lmao>>>
    Any essay that includes the words "wind tunnel test" is obviously talking about the road environment which bears little resemblance to the mountain biking world.

    As for off-road crank length, this dimension is 100% rider preference.

    This statement is my singular opinion based on 33 years of off-road cycling and employing various length cranks from 170-202mm throughout this time. I used to have a strong opinion about which length crank is "best" for a given leg length (particularly during my decade of singlespeeding) but since then I've become convinced that mountain bike crank length does not matter in the least when it comes to performance -- it is a comfort issue.

    Bottom line: This isn't road biking. Run whichever length crank feels best to you. Adjust your gearing accordingly. Truth.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  49. #49
    Cymru am byth!
    Reputation: cwtch's Avatar
    Join Date
    Apr 2018
    Posts
    94
    Quote Originally Posted by chas_martel View Post
    Who has 172.5 mm cranks?
    As stated road cranks. Shimano SRAM and Campy all make 172.5 road cranks. I don't know of any MTB cranks that length.
    he smelt of triflow, had a nice smile, with kind eyes... so I married him

  50. #50
    Cymru am byth!
    Reputation: cwtch's Avatar
    Join Date
    Apr 2018
    Posts
    94
    Quote Originally Posted by J. Random Psycho View Post
    But but I only have one gear..


    BTW I tested 165 mm cranks on SS recently (low BB so they had to run short cranks), with the gear chosen to get the needed gain ratio. It felt all wrong!
    Agreed, for single-speed 175 is all I have found that doesn't feel wonky. (Wonky an industry term for: not right for me)
    he smelt of triflow, had a nice smile, with kind eyes... so I married him

  51. #51
    mtbr member
    Reputation: ladljon's Avatar
    Join Date
    Nov 2011
    Posts
    299
    People who havnít tried anything different have no clue.....just going the way of the crowd, and say so.....35yrs of mtbiking.....running 135mm cranks for three yrs

  52. #52
    mtbr member
    Reputation: kitejumping's Avatar
    Join Date
    Sep 2010
    Posts
    680
    I have run 175, 170, 165s, most of my bikes are 165s now, feet are closer to the bottom bracket so easier to manual and get behind the rear wheel, better pedal clearance when pedaling through rocks, and they weigh less. If you're thinking about trying shorter cranks, go for it and you likely wont be disappointed.

  53. #53
    mtbr member
    Reputation: Dr Evil's Avatar
    Join Date
    Sep 2015
    Posts
    477
    I just changed the 175mm cranks on my 2017 Fuel EX-8 27.5+ to 165mm. It is one of the best things I did to my bike. Basically no more pedal strikes, I now pedal through turns more as well as through technical rock patches. Certainly inspires confidence. I'm 5'4" with a 29" inseam.

  54. #54
    mtbr member
    Reputation: One Pivot's Avatar
    Join Date
    Nov 2009
    Posts
    7,434
    In technical stuff, I often end up at a weird leg angle with 175's that is very difficult to pedal. I can't apply power at that angle. It happens less with 170's. Next cranks will be 165's. I tried 160's but the options are pretty bad.

    I'm 5'7. A shorter crank never felt like it had less torque. Human biometrics really play a bigger role than simple mechanics.

  55. #55
    Trail Gnome
    Reputation: griz's Avatar
    Join Date
    Jan 2011
    Posts
    3,306
    Quote Originally Posted by stripes View Post
    Depends on the rider and how their measurements are. I ran the gear calculator and it said 163mm for me. This year I switched from 165mm to 160mm and I wonít go back. 160mm works well for me. Iím 5í4Ē and have a 29.5Ē inseam.
    Iím 6í2Ē, I always ran 180mm on my hard tails...this was a long time ago. I switched to 175mm on suspension bikes, and have stayed at that length. I did ride someoneís bike that had 170mm crankarms on it...it felt like a little kids bike

  56. #56
    mtbr member
    Reputation: EatsDirt's Avatar
    Join Date
    Jan 2014
    Posts
    837
    It's all about aerodynamics. Tiny cranks and skin suits.

  57. #57
    mtbr member
    Reputation: Gman086's Avatar
    Join Date
    Jul 2004
    Posts
    4,410
    Quote Originally Posted by stripes View Post
    Depends on the rider and how their measurements are. I ran the gear calculator and it said 163mm for me. This year I switched from 165mm to 160mm and I wonít go back. 160mm works well for me. Iím 5í4Ē and have a 29.5Ē inseam.
    Uuuhhmmm... you DO realize that my post was from TEN FREAKIN YEARS AGO!!! I've since changed my tune and won't run anything longer that 170. The dumb argument about leverage is that you LOSE leg leverage with longer cranks because your knees have to come up higher. I actually get knee and hip pain with 175 cranks these days and I'm noticeably stronger on the uphills with 170's.

    Have FUN!

    G MAN
    "There's two shuttles, one to the top and one to the hospital" I LOVE this place!!!

  58. #58
    mtbr member
    Reputation:
    Join Date
    Aug 2017
    Posts
    304
    The torque difference is negligible, and as soon as you shift a gear it's gone.
    So if they feel good to you, don't cause a fit problem, knee pain, what have you, then rock on!

  59. #59
    Here, diagonally!
    Reputation: JACKL's Avatar
    Join Date
    Sep 2011
    Posts
    1,983
    I'm 6'2" and run 175s. They're fine for me (as far as I know), but it doesn't make sense to me that riders of all heights would run 175s.

  60. #60
    mtbr member
    Reputation:
    Join Date
    Apr 2014
    Posts
    314
    Quote Originally Posted by Dr Evil View Post
    I just changed the 175mm cranks on my 2017 Fuel EX-8 27.5+ to 165mm. It is one of the best things I did to my bike. Basically no more pedal strikes, I now pedal through turns more as well as through technical rock patches. Certainly inspires confidence. I'm 5'4" with a 29" inseam.
    How is the climbing performance with the shorter cranks? I am also 5'4" and find steep climbs awkward with my 170mms, do the shorter cranks have an impact?

  61. #61
    mtbr member
    Reputation: ladljon's Avatar
    Join Date
    Nov 2011
    Posts
    299
    STILL LMAO....so entertaining....tiny cranks and skin suits....really! LMAO...Four yrs ago when I made the change to shorter and realized how much better they felt and the advantages....no one could tell I had shorter cranks, and really wanted to keep it as a secret weapon.

  62. #62
    mtbr member
    Reputation: EatsDirt's Avatar
    Join Date
    Jan 2014
    Posts
    837
    Quote Originally Posted by ladljon View Post
    STILL LMAO....so entertaining....tiny cranks and skin suits....really! LMAO...Four yrs ago when I made the change to shorter and realized how much better they felt and the advantages....no one could tell I had shorter cranks, and really wanted to keep it as a secret weapon.
    I've spend a minimum 10k miles each on 170, 172.5, and 175 cranks, at times alternating between each. Pffft, secret weapon. You're silly.

  63. #63
    mtbr member
    Reputation: ladljon's Avatar
    Join Date
    Nov 2011
    Posts
    299
    Yep, a bit silly, out of the box free thinker, open minded sigma...will not follow the group, unless we'er on the same page. Been around long enough to know what I like. Just glad I'm not a person so closed minded to never experience new ways of learning....

  64. #64
    BOOM goes the dynamite!
    Reputation: noapathy's Avatar
    Join Date
    Jun 2008
    Posts
    3,502
    Quote Originally Posted by Gman086 View Post
    Uuuhhmmm... you DO realize that my post was from TEN FREAKIN YEARS AGO!!! I've since changed my tune and won't run anything longer that 170. The dumb argument about leverage is that you LOSE leg leverage with longer cranks because your knees have to come up higher. I actually get knee and hip pain with 175 cranks these days and I'm noticeably stronger on the uphills with 170's.

    Have FUN!

    G MAN
    Same reason I switched to 170...well, that and a few less pedal strikes.

  65. #65
    mtbr member
    Reputation: Dr Evil's Avatar
    Join Date
    Sep 2015
    Posts
    477
    Quote Originally Posted by fdes View Post
    How is the climbing performance with the shorter cranks? I am also 5'4" and find steep climbs awkward with my 170mms, do the shorter cranks have an impact?
    Climbing is great with the shorter cranks. It really doesn't have much of a different feel to me.

  66. #66
    mtbr member
    Reputation: EatsDirt's Avatar
    Join Date
    Jan 2014
    Posts
    837
    Quote Originally Posted by ladljon View Post
    Yep, a bit silly, out of the box free thinker, open minded sigma...will not follow the group, unless we'er on the same page. Been around long enough to know what I like. Just glad I'm not a person so closed minded to never experience new ways of learning....
    Since you're so open minded and experience new way of learning, perhaps you should educate yourself about personal preferences/etc and how they might play into crank length. Or maybe you already know everything there is to know since you've read a few online articles...? In that case keep on with that "LMAO".

  67. #67
    mtbr member
    Reputation: R_Pierce's Avatar
    Join Date
    May 2017
    Posts
    929
    Im currently on 165's and dont plan to change. Gaining a little over 3/8 of an inch at the pedal goes a long ways for pedal strikes IMO.

  68. #68
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    8,845
    To each his own but frankly I'm surprised at the number of riders who're willing to -- even choosing to -- employ shorter cranks to avoid pedal strikes.

    Although I've stated my belief that crank length is a matter of choice based primarily on comfort rather than performance, personally I still consider crank length a factor in proper bike fit. Personally if my options to avoid pedal strikes are (1) choose a frame with adequate BB height or (2) employ shorter cranks, I'll choose my frame wisely. I won't tolerate being forced into a specific crank length by a design limitation of my frame -- namely too low a BB height -- I want to choose whatever crank length I like.

    Full disclosure: I run 185mm cranks. For the record, I'm not advocating long cranks for anyone else.

    As I said, to each his own. I'm just not sure that every rider reading these forums understands that embracing short cranks simply because the bike industry is shoving the low BB pill down our throats is the right solution, if it's actually a solution at all. It may solve a problem, but this doesn't mean it's the ideal solution. It's the easy solution. It's the less expensive solution. It isn't the solution for me, personally.

    On the other hand if riders who choose shorter cranks genuinely want them to the degree that they'd run such cranks even if they weren't suffering pedal strikes, well, more power to 'em. This would prove that shorter cranks certainly are ideal for those particular riders. But if they're simply buying them to get rid of the pedal strike issue, they may not be seeing the bigger picture. Proper length cranks don't cause pedal strikes, low BBs do.

    Crank length is the cart, BB height is the horse.

    Carry on.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  69. #69
    mtbr member
    Reputation: R_Pierce's Avatar
    Join Date
    May 2017
    Posts
    929
    Quote Originally Posted by Sparticus View Post
    To each his own but frankly I'm surprised at the number of riders who're willing to -- even choosing to -- employ shorter cranks to avoid pedal strikes.

    Although I've stated my belief that crank length is a matter of choice based primarily on comfort rather than performance, personally I still consider crank length a factor in proper bike fit. Personally if my options to avoid pedal strikes are (1) choose a frame with adequate BB height or (2) employ shorter cranks, I'll choose my frame wisely. I won't tolerate being forced into a specific crank length by a design limitation of my frame -- namely too low a BB height -- I want to choose whatever crank length I like.

    Full disclosure: I run 185mm cranks. For the record, I'm not advocating long cranks for anyone else.

    As I said, to each his own. I'm just not sure that every rider reading these forums understands that embracing short cranks simply because the bike industry is shoving the low BB pill down our throats is the right solution, if it's actually a solution at all. It may solve a problem, but this doesn't mean it's the ideal solution. It's the easy solution. It's the less expensive solution. It isn't the solution for me, personally.

    On the other hand if riders who choose shorter cranks genuinely want them to the degree that they'd run such cranks even if they weren't suffering pedal strikes, well, more power to 'em. This would prove that shorter cranks certainly are ideal for those particular riders. But if they're simply buying them to get rid of the pedal strike issue, they may not be seeing the bigger picture. Proper length cranks don't cause pedal strikes, low BBs do.

    Crank length is the cart, BB height is the horse.

    Carry on.
    =sParty
    And then when a guy goes from 175 to 170 to 165 and notices absolutely NO difference in power, efficiency, etc except ground clearance... Might as well get what you can.

    Sent from my LG-H931 using Tapatalk

  70. #70
    always licking the glass
    Reputation: stripes's Avatar
    Join Date
    Sep 2016
    Posts
    1,336
    Quote Originally Posted by ladljon View Post
    STILL LMAO....so entertaining....tiny cranks and skin suits....really! LMAO...Four yrs ago when I made the change to shorter and realized how much better they felt and the advantages....no one could tell I had shorter cranks, and really wanted to keep it as a secret weapon.
    Yep same here. Iím faster on shorter cranks and hip pain free. I can even run a bigger chainring.

    Just because something is industry standard, it doesnít mean it works for everyone.
    Guerrilla Gravity BAMF, Colorado Front Range
    Writer, MTB4Her.

  71. #71
    always licking the glass
    Reputation: stripes's Avatar
    Join Date
    Sep 2016
    Posts
    1,336
    Quote Originally Posted by fdes View Post
    How is the climbing performance with the shorter cranks? I am also 5'4" and find steep climbs awkward with my 170mms, do the shorter cranks have an impact?
    I'm also 5'4". 29.5" cycling inseam.

    I started out on 175mm cranks, and I noticed hip pain. It was also a serious issue for me to climb, and I had a horrible dead spot in the pedal stroke because the cranks felt too long for me.

    I went down to 170mm, and not much better, so I switched to a 28t chainring. That improved things slightly, but I didn't feel likei t was getting better.

    I switched to 165mm for a couple of years, and that helped a bit, still running a 28t chainring. At this length, my hip pain is gone, but still didn't feel quite right. Felt like I wasn't going anywhere, and the 30t felt like it had a dead spot in it, just like when I was riding with the 175mm cranks.

    This year I switched to 160mm cranks, and the 28t felt like I could never get out of granny gear, even in the bigger gears. So I switched to a 30t on the 160mm cranks, and I'm climbing faster than I did before. Found that dead spot in my pedal stroke was gone, and the shorter cranks seem to be the step in the right direction for me. People have told me to go to a 26t on the shorter cranks, but that wouldn't have worked for me.

    It does take a bit for your legs to get used to it, but it's not impossible. I find that now short and bursty type of climbs I fly up now, and I'm faster on the longer climbs (not fast by any means), but this seemed to help me quite a bit.

    I'll probably end up putting 155mm cranks on my DH bike.
    Guerrilla Gravity BAMF, Colorado Front Range
    Writer, MTB4Her.

  72. #72
    mtbr member
    Reputation:
    Join Date
    Dec 2014
    Posts
    1,124
    Quote Originally Posted by Sparticus View Post
    To each his own but frankly I'm surprised at the number of riders who're willing to -- even choosing to -- employ shorter cranks to avoid pedal strikes.
    Proper length cranks don't cause pedal strikes, low BBs do. Crank length is the cart, BB height is the horse.

    Carry on.
    =sParty
    C'mon sparty, you're still missing something here. I however, am not sure what it is you are missing, but I do know that despite a slacker HT angle and larger rim/tire my new bike rails flat corners better than the old 26" XC did. When I asked why it turned better I was told it's a combo of short CS and low BB.
    I got use to the shorter cranks that came on the new bike (they did annoy me at 1st) but I am only 5' 7" w/ 32" inseam. I WAS slower at first (3lb heavier bike too) but after some training to strengthen up it didn't take long to exceed my old times.
    oops I wasn't clipped in

  73. #73
    mtbr member
    Reputation: kitejumping's Avatar
    Join Date
    Sep 2010
    Posts
    680
    Didn't mention my height before, I'm 6ft, ride a large nomad 4 with 200mm fall line dropper post and 165 cranks, short cranks work great for seated spinning at a faster cadence when climbing, feels like it takes less effort to me vs longer cranks. I used to ride a fair amount of trials on 175mm cranks and have no problem doing pedal kick gaps or pedal punches / wheel swaps on the 165s. Also running an oval ring and flats so maybe that plays into it too. I think wide bars factor into how much torque and power you can put down when standing and mashing more than crank arm length.

  74. #74
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    8,845
    Quote Originally Posted by jim c View Post
    C'mon sparty, you're still missing something here. I however, am not sure what it is you are missing, but I do know that despite a slacker HT angle and larger rim/tire my new bike rails flat corners better than the old 26" XC did. When I asked why it turned better I was told it's a combo of short CS and low BB.
    I got use to the shorter cranks that came on the new bike (they did annoy me at 1st) but I am only 5' 7" w/ 32" inseam. I WAS slower at first (3lb heavier bike too) but after some training to strengthen up it didn't take long to exceed my old times.
    Maybe I am missing something, Jim. Please tell me what it is. I want to know and in so saying, I don't intend to sound flip. I mean it. To prove my sincerity I'll tell you I'm actually considering buying some 175mm cranks to see if I might like them after a quarter century riding 185 & 195mm cranks.

    Meanwhile consider this. Seeking a lower center of gravity? With longer cranks a rider actually lowers his saddle. I've never had any problem bending my knees when I'm descending with the saddle down and I don't imagine that a BB that's 5mm lower really makes much of a difference in handling but then again maybe it does. I've been riding mountain bikes long enough that I notice when my saddle is say, 2mm too low or too high, I notice the difference between a 780mm handlebar and an 800mm bar, so yeah, maybe a change in BB height this insignificant is noticeable and matters.

    There are two subjects at hand here: crank length and BB height. I'm not going to change my frame's BB height (nor do I want to) but I'll probably give short cranks a try based largely on the raves of people in this and other recent MTBR threads. It's been too long since I've ridden them. I'm out of touch. Who knows, maybe I'll like them now.

    In any case it's good to hear from you again.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  75. #75
    mtbr member
    Reputation:
    Join Date
    Dec 2014
    Posts
    1,124
    Quote Originally Posted by Sparticus View Post
    Maybe I am missing something, Jim. Please tell me what it is. I want to know and in so saying, I don't intend to sound flip.

    In any case it's good to hear from you again.
    =sParty
    I wish I was informed enough to say what exactly goes on when we feel diferent bikes handling differently. Like I typed above I don't really know. I learned to ride a long, low, slack machine faster than my older bike. Some variables include my desire to go faster and the effort I put out to make that happen. Wheel size, maybe 27.5 is faster on smooth flowy hard-pack as well as rocky-rooty turns. I also learned to pedal with my saddle lower (than before) so I could sit instead of just dropping it and running out of steam quickly.
    As to crank length, like you I like the longer 180 better. I told myself it was a small compromise if the trade-off was better handling. I found it interesting to read that some riders felt a 160mm crankset was an improvement because I missed those longer arms.
    oops I wasn't clipped in

  76. #76
    mtbr member
    Reputation:
    Join Date
    Sep 2014
    Posts
    839
    I've gone to 170's from 175 on all my mtb's. One is for pedal clearance, which, surprisingly enough, results in much fewer pedal strikes. Yes, .2 of an inch can make a difference, just ask frame designers about bottom bracket heights. But as an added benefit, since I'm pretty short, my high leg doesn't have to come up as far, resulting in less hip flexor issues and less need for stretching after long rides. 10 cm's less leg lift several thousand times over the course of a ride makes a difference for my right leg for some reason.
    You can't buy happiness. But you can buy a bike. And that's pretty close.

  77. #77
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    8,845
    Quote Originally Posted by BmanInTheD View Post
    I've gone to 170's from 175 on all my mtb's. One is for pedal clearance, which, surprisingly enough, results in much fewer pedal strikes. Yes, .2 of an inch can make a difference, just ask frame designers about bottom bracket heights. But as an added benefit, since I'm pretty short, my high leg doesn't have to come up as far, resulting in less hip flexor issues and less need for stretching after long rides. 10 cm's less leg lift several thousand times over the course of a ride makes a difference for my right leg for some reason.
    You say you're pretty short. My inseam is 36". It's possible that even with my roughly half-inch longer 185mm cranks, my knees & hips bend less than yours do with 170mm cranks. We'll probably never know and it doesn't matter anyway, but it's possible.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  78. #78
    mtbr member
    Reputation: kitejumping's Avatar
    Join Date
    Sep 2010
    Posts
    680
    I think the big thing is to try different crank lengths, similar to saddles everyone is different and the generic 175mm length isn't right for everyone.

  79. #79
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    8,845
    Quote Originally Posted by kitejumping View Post
    I think the big thing is to try different crank lengths, similar to saddles everyone is different and the generic 175mm length isn't right for everyone.
    Bingo. Agree 100%.

    Now try to find a frame that will allow you to do that if you want to experiment with longer cranks. More people are swapping to shorter cranks every day due to the ever lowering BB. What about those who want to experiment with crank length in the other direction?

    I'll reiterate I'm not favoring any single crank length even generally -- shorter vs longer. That's absolutely each rider's choice. I'm saying the bike industry has limited our ability to choose and many riders are making their choice of crank length based on the convenient choice -- shorter cranks -- rather than considering the FAR less convenient option -- a frame with a higher BB in order to avoid pedal strikes. Frames with higher BBs allow some riders to fit cranks that are more appropriate for their inseam measurement yet still avoid pedal strikes.

    It ain't easy to do, finding such frames. Especially considering that in addition to my preferred BB height, I still want to choose all other frame attributes -- travel, HA, chainstay length, STA, blah, blah. Maybe I need to go custom. Tragic, IMO.

    Look back 5 years and every decade before that, nobody was rushing toward shorter cranks. Low BBs instigated this phenomenon, it wasn't because the market lacked a supply of short cranks 5 or more years ago.

    Did riders demand lower BBs or did the bike industry decide that's what we're all going to buy in 2018?

    Food for thought. Again, not calling anybody wrong.

    I'm going riding now.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  80. #80
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    870
    Quote Originally Posted by Sparticus View Post
    Look back 5 years and every decade before that, nobody was rushing toward shorter cranks. Low BBs instigated this phenomenon, it wasn't because the market lacked a supply of short cranks 5 or more years ago.

    Did riders demand lower BBs or did the bike industry decide that's what we're all going to buy in 2018?

    Food for thought. Again, not calling anybody wrong.

    I'm going riding now.
    =sParty
    ^^Where do you get the idea that no one rushed forward for shorter cranks? The movement to shorter cranks started nearly two decades ago! Cervelo has a good summary of the movement starting with the pivotal study in 2001.

    During the study, they repeated their efforts while systematically testing the following crank lengths: 120, 145, 170, 195 and 220mm. Believe it or not, the tests showed no statistical difference in maximum power among the three middle crank lengths (145, 170 and 195mm).

    With the leverage-dependency myth debunked to a certain degree, it was the application of these lessons that really highlighted the value of this study.
    Bottom line, ride what you like or fits your body short or long.

    https://www.cervelo.com/en/engineeri...n-crank-length

  81. #81
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    8,845
    Quote Originally Posted by thesmokingman View Post
    ^^Where do you get the idea that no one rushed forward for shorter cranks? The movement to shorter cranks started nearly two decades ago! Cervelo has a good summary of the movement starting with the pivotal study in 2001.

    https://www.cervelo.com/en/engineeri...n-crank-length
    Put the pipe down, smokingman, you're citing a road bike study. The caption under the photo in the study you linked includes these words: "many triathletes and time trialists are switching to shorter cranks." And here's the photo from your linked study:
    crank lengths 175 vs 170-cervelo-study-pic.jpg
    Not exactly a mountain bike, is it.

    Yeah, roadies have been employing shorter cranks for quite a few years now. But just as mountain bikers don't care about aerodynamics or slick tires like roadies do, it's inappropriate to assume the motivations for employing shorter cranks is the same from one discipline to the other.

    Not only did the rush to shorter cranks on the road begin longer ago than it did in the world of mountain biking, it happened for a different reason. Roadies like to spin. Mountain bikers did it for ground clearance. It may be true that once mountain bikers put shorter cranks on in order to avoid pedal strikes, they discovered through the process that they also prefer the feel of short cranks &/or suffered no loss in power delivery.

    Nowhere did I say longer cranks provide more power. I said crank length is a comfort issue. Choose the length you like and adjust your gearing accordingly. Personally I'm most comfortable on 185mm cranks. I never said nor implied that anyone else should be riding long cranks. In fact I went out of my way to say the opposite.

    Quote Originally Posted by thesmokingman View Post
    Bottom line, ride what you like or fits your body short or long.
    You paraphrased me. Okay, you may now smoke 'em if you got 'em.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  82. #82
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    870
    Quote Originally Posted by Sparticus View Post
    Put the pipe down, smokingman, you're citing a road bike study. The caption under the photo in the study you linked includes these words: "many triathletes and time trialists are switching to shorter cranks." And here's the photo from your linked study:
    Click image for larger version. 

Name:	Cervelo study pic.jpg 
Views:	48 
Size:	98.0 KB 
ID:	1197361
    Not exactly a mountain bike, is it.

    Yeah, roadies have been employing shorter cranks for quite a few years now. But just as mountain bikers don't care about aerodynamics or slick tires like roadies do, it's inappropriate to assume the motivations for employing shorter cranks is the same from one discipline to the other.

    Not only did the rush to shorter cranks on the road begin longer ago than it did in the world of mountain biking, it happened for a different reason. Roadies like to spin. Mountain bikers did it for ground clearance. It may be true that once mountain bikers put shorter cranks on in order to avoid pedal strikes, they discovered through the process that they also prefer the feel of short cranks &/or suffered no loss in power delivery.

    Nowhere did I say longer cranks provide more power. I said crank length is a comfort issue. Choose the length you like and adjust your gearing accordingly. Personally I'm most comfortable on 185mm cranks. I never said nor implied that anyone else should be riding long cranks. In fact I went out of my way to say the opposite.


    You paraphrased me. Okay, you may now smoke 'em if you got 'em.
    =sParty
    Obviously its a road study. MTB's throw too many environment variables in. And in testing mtb in theory, you'd remove all the trail/terrain variables anyways to get to the heart of the matter. The bottom line is that there is no leverage ratio advantage so that leaves using any size that you like or fits you better.

    The point in quoting you not so much agreeing with you on the fundamental for fit, is that this shorter crank movement has been around for a long freaking time, yet the leverage ratio myth will not die.

  83. #83
    Norūwegr
    Reputation: Vegard's Avatar
    Join Date
    Jul 2009
    Posts
    1,812
    I went from 175mm to 165 and I can't tell the difference on my 29er.

  84. #84
    mtbr member
    Reputation: ALimon's Avatar
    Join Date
    Oct 2017
    Posts
    711
    Simply put, cranks are a matter of preference. Many variables should be considered when choosing a crank size. Ego isnít one of them.

  85. #85
    mtbr member
    Reputation: EatsDirt's Avatar
    Join Date
    Jan 2014
    Posts
    837
    Quote Originally Posted by thesmokingman View Post
    And in testing mtb in theory, you'd remove all the trail/terrain variables anyways to get to the heart of the matter. ---------- the leverage ratio myth will not die.
    In removing all terrain variables... you're basically saying it's the same as road??? Is the concept of using a larger lever to push a bigger gear/lower cadence lost on everyone? I'm not saying go big and you'll produce more watts, have lower hr, higher lactic threshold... but I am saying there are tradeoffs.

  86. #86
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    870
    Quote Originally Posted by EatsDirt View Post
    In removing all terrain variables... you're basically saying it's the same as road??? Is the concept of using a larger lever to push a bigger gear/lower cadence lost on everyone? I'm not saying go big and you'll produce more watts, have lower hr, higher lactic threshold... but I am saying there are tradeoffs.
    Read the data or that is the summary, there is no statistical difference from 145mm to 195mm. It's on you to prove there is difference because the science doesn't show it.

  87. #87
    mtbr member
    Reputation: EatsDirt's Avatar
    Join Date
    Jan 2014
    Posts
    837
    Go ride a kids bike, tiny cranks, and tell me you can lurch, half crank, accelerate from a stop, push over an obstacle, etc like you can with avg length cranks (assuming same gear inches). While extreme, it's varying degrees of the inherent tradeoff. Studies have mentioned this.

  88. #88
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    870
    Quote Originally Posted by EatsDirt View Post
    Go ride a kids bike, tiny cranks, and tell me you can lurch, half crank, accelerate from a stop, push over an obstacle, etc like you can with avg length cranks. While extreme, it's varying degrees of the inherent tradeoff. Studies have mentioned this.
    What studies? Shit, I don't give a crap what you or anyone uses, I just linked to the data that showed that there is no statistical difference for the typical crank length ranges. Why would I ride a kids bike to make your point??

  89. #89
    mtbr member
    Reputation: EatsDirt's Avatar
    Join Date
    Jan 2014
    Posts
    837
    If you're going to say leverage doesn't matter, you might as well experience extreme low leverage. Your theory of "the leverage ration myth" would prove that kiddie cranks would be just as efficient. It's not. Maybe we agree that on a road bike you don't have nearly the dynamic efforts as with mtb...? Especially when it comes to tech climbing..? I don't give a flying fvck what you ride, but if you're going to talk in absolutes siting studies that might not paint the whole picture... well.

  90. #90
    mtbr member
    Reputation: targnik's Avatar
    Join Date
    Jan 2014
    Posts
    4,628
    OP here, good to see a healthy (obsessive?) debate going on.

    I found 170mm cranks on a hard tail had less pedal strikes than 175mm cranks i.e. with cranks at 12 & 6 o'clock, pedals are 5mm further from the trail. ;-)

    One possible positive, for longer cranks (stirs the pot) is when you're bombing down hill and your cranks are at 3 & 9 o'clock your base will be a little longer i.e. more stable ^^

    Let the mini series continue!

    :more-popcorn:

    'Born to ride!'
    "Mountain biking: the under-rated and drug-free antidepressant"

  91. #91
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    8,845
    Quote Originally Posted by targnik View Post
    One possible positive, for longer cranks (stirs the pot) is when you're bombing down hill and your cranks are at 3 & 9 o'clock your base will be a little longer i.e. more stable ^^

    Let the mini series continue!

    :more-popcorn:

    'Born to ride!'
    I donít know about the longer base thing, havenít felt much difference in that between crank lengths Iíve tried.

    But back to what feels best and something I personally like about longer cranks.

    Thereís a difference between power and torque. As has been pointed out already, studies show people are able to generate as much power with short cranks as they can with longer ones. But I donít believe short cranks can generate as much torque. Let me illustrate.

    You know when youíre trying to loosen a stuck nut with an 8-inch Crescent wrench and you push and you tug and finally the nut breaks free and you bash your knuckles on the sharpest piece of nearby metal and get all bloody and pissed off? When, if youíd put a 15-inch cheater bar on the wrench, you could have easily broken the nut free with one gentle push? Thatís what longer cranks do. The same amount of energy is expended whether you use a short wrench or a long one, itís the way the energy is applied thatís different and itís the same difference with cranks.

    I canít count the number of times Iíve climbed (cleaned) steep tech sections that my buddies on shorter cranks havenít and I credit my ability to mete power more, shall we say gently(?) because my cranks are a half-inch to an inch longer than theirs. No, Iím not making more power. Iím applying torque. And thatís the best argument Iíll make in favor of longer cranks. They apply torque differently.

    Roadies donít need it ó they donít encounter techy steeps.

    And not everyone whoíd like to experiement with longer cranks should. I agree with people who say the more acute angles on knee & hip joints may not be a good thing. But for those of us with long legs (my inseam is 36Ē), that point is moot.

    Iíve been involved in countless crank length discussions on these forums during the past couple decades. The only time I get frustrated is when someone (most people, actually) whoíve never tried long cranks ó and by ďlongĒ I mean over 180mm ó start saying thereís nothing to them. They canít know. They donít know what that applied torque feels like because theyíve never experienced it. And yet theyíre experts.

    Eventually I decided to stay out of crank length arguments altogether. Nobody wins an argument on the internet. And yet here I am. Trying to defend my right to choose whatís right for myself. Again.

    Carry on.
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  92. #92
    mtbr member
    Reputation: R_Pierce's Avatar
    Join Date
    May 2017
    Posts
    929
    Quote Originally Posted by Sparticus View Post
    I donít know about the longer base thing, havenít felt much difference in that between crank lengths Iíve tried.

    But back to what feels best and something I personally like about longer cranks.

    Thereís a difference between power and torque. As has been pointed out already, studies show people are able to generate as much power with short cranks as they can with longer ones. But I donít believe short cranks can generate as much torque. Let me illustrate.

    You know when youíre trying to loosen a stuck nut with an 8-inch Crescent wrench and you push and you tug and finally the nut breaks free and you bash your knuckles on the sharpest piece of nearby metal and get all bloody and pissed off? When, if youíd put a 15-inch cheater bar on the wrench, you could have easily broken the nut free with one gentle push? Thatís what longer cranks do. The same amount of energy is expended whether you use a short wrench or a long one, itís the way the energy is applied thatís different and itís the same difference with cranks.

    I canít count the number of times Iíve climbed (cleaned) steep tech sections that my buddies on shorter cranks havenít and I credit my ability to mete power more, shall we say gently(?) because my cranks are a half-inch to an inch longer than theirs. No, Iím not making more power. Iím applying torque. And thatís the best argument Iíll make in favor of longer cranks. They apply torque differently.

    Roadies donít need it ó they donít encounter techy steeps.

    And not everyone whoíd like to experiement with longer cranks should. I agree with people who say the more acute angles on knee & hip joints may not be a good thing. But for those of us with long legs (my inseam is 36Ē), that point is moot.

    Iíve been involved in countless crank length discussions on these forums during the past couple decades. The only time I get frustrated is when someone (most people, actually) whoíve never tried long cranks ó and by ďlongĒ I mean over 180mm ó start saying thereís nothing to them. They canít know. They donít know what that applied torque feels like because theyíve never experienced it. And yet theyíre experts.

    Eventually I decided to stay out of crank length arguments altogether. Nobody wins an argument on the internet. And yet here I am. Trying to defend my right to choose whatís right for myself. Again.

    Carry on.
    =sParty
    Nobody is telling you to run shorter cranks. Run what you want to run. That's the benefit of having such an array to choose from.

    Sent from my LG-H931 using Tapatalk

  93. #93
    mbtr member
    Reputation: scottzg's Avatar
    Join Date
    Sep 2006
    Posts
    4,899
    I'm fairly ambivalent about crank lengths. I've tried between 160 and 190, seems like they're all OK to me so long as i have appropriate gearing and ground clearance. I think it's like oval chainrings; they work fine and have a different character, so some people will like them and some won't and both opinions are valid.

    It's pretty lame that long cranks are rare and expensive, but it makes sense since they're only a sensible fit for tall people and half of them won't care. Then the lack of long cranks pushes BB heights down and most of the rest of the tall folk don't want long cranks anyway. Chicken-egg.

    My only real rub with short cranks is you need a longer dropper post. 160 cranks and a 125mm dropper is a no-go, but 175 cranks and it's all good. (for me, i have a knee injury that prevents lowering my saddle more than ~130mm drop, so oddly that restricts how low the BB can be.)


    Quote Originally Posted by Sparticus View Post

    You know when youíre trying to loosen a stuck nut with an 8-inch Crescent wrench and you push and you tug and finally the nut breaks free and you bash your knuckles on the sharpest piece of nearby metal and get all bloody and pissed off? When, if youíd put a 15-inch cheater bar on the wrench, you could have easily broken the nut free with one gentle push? Thatís what longer cranks do. The same amount of energy is expended whether you use a short wrench or a long one, itís the way the energy is applied thatís different and itís the same difference with cranks.
    This isn't a very good analogy because it misses that there are 2 levers in a bike drivetrain, both the crank length and the gears.
    "Things that are complex are not useful, Things that are useful are simple."
    Mikhail Kalashnikov

  94. #94
    Out spokin'
    Reputation: Sparticus's Avatar
    Join Date
    Dec 1999
    Posts
    8,845
    Quote Originally Posted by R_Pierce View Post
    Nobody is telling you to run shorter cranks.
    I feel like the bike industry is due to ever-dropping BB heights.

    Quote Originally Posted by scottzg View Post
    I'm fairly ambivalent about crank lengths. I've tried between 160 and 190, seems like they're all OK to me so long as i have appropriate gearing and ground clearance. I think it's like oval chainrings; they work fine and have a different character, so some people will like them and some won't and both opinions are valid.

    It's pretty lame that long cranks are rare and expensive, but it makes sense since they're only a sensible fit for tall people and half of them won't care. Then the lack of long cranks pushes BB heights down and most of the rest of the tall folk don't want long cranks anyway. Chicken-egg.

    My only real rub with short cranks is you need a longer dropper post. 160 cranks and a 125mm dropper is a no-go, but 175 cranks and it's all good. (for me, i have a knee injury that prevents lowering my saddle more than ~130mm drop, so oddly that restricts how low the BB can be.)

    This isn't a very good analogy because it misses that there are 2 levers in a bike drivetrain, both the crank length and the gears.
    Excellent points. ďYou must spread some Reputation around before giving it to scottzg again.Ē
    =sParty
    disciplesofdirt.org

    We don't quit riding because we get old.
    We get old because we quit riding.

  95. #95
    mtbr member
    Reputation:
    Join Date
    Jan 2009
    Posts
    870
    Quote Originally Posted by EatsDirt View Post
    If you're going to say leverage doesn't matter, you might as well experience extreme low leverage. Your theory of "the leverage ration myth" would prove that kiddie cranks would be just as efficient. It's not. Maybe we agree that on a road bike you don't have nearly the dynamic efforts as with mtb...? Especially when it comes to tech climbing..? I don't give a flying fvck what you ride, but if you're going to talk in absolutes siting studies that might not paint the whole picture... well.
    I'd said nothing of the sort. Let me repeat, the data shows no statistical proof that crank sizes in the named range shows any difference. You however got emotional and have jumped to extremes to make your points. You cite studies but then do not show this proof. You further cite opinion as fact and accuse me of talking in absolutes when I've done no such thing. Again as I wrote before use whatever crank size you want, I don't give a shit.

    Also let me add that if you feel you need a longer crank for that techy area then so be it. Good for you. But to say it must be because of this, that is opinion. You've shown no proof to support it as fact. Hell, I'm not even sure how one can quantify that point. How big of a rock to climb, what gearing, what terrain, how steep of a grade, etc etc? There are too many variables to even attempt...

  96. #96
    mtbr member
    Reputation:
    Join Date
    Apr 2012
    Posts
    269
    Something I always thought was a bit odd, everyone wants a lower BB, but then they run shorter cranks to keep from bashing them. But when you switch to a shorter crank you need to raise the seat to compensate-which then raises your center of gravity right? Which then kinda negates the benefits of a lower BB.

  97. #97
    mtbr member
    Reputation: kitejumping's Avatar
    Join Date
    Sep 2010
    Posts
    680
    Quote Originally Posted by thesmokingman View Post
    I'd said nothing of the sort. Let me repeat, the data shows no statistical proof that crank sizes in the named range shows any difference. You however got emotional and have jumped to extremes to make your points. You cite studies but then do not show this proof. You further cite opinion as fact and accuse me of talking in absolutes when I've done no such thing. Again as I wrote before use whatever crank size you want, I don't give a shit.

    Also let me add that if you feel you need a longer crank for that techy area then so be it. Good for you. But to say it must be because of this, that is opinion. You've shown no proof to support it as fact. Hell, I'm not even sure how one can quantify that point. How big of a rock to climb, what gearing, what terrain, how steep of a grade, etc etc? There are too many variables to even attempt...
    Yep! As a rider with trials skills (I can gap things on the rear wheel, climb rock ledges bar height) assuming you're using the standard 1.2 gear ratio for 26, similar to that for 27.5, I can tell you that the minor difference in torque between crank arm length is negligible in all real world cases when climbing technical things. Skills matter much more than a 10mm difference in crank arm length.

  98. #98
    mtbr member
    Reputation: kitejumping's Avatar
    Join Date
    Sep 2010
    Posts
    680
    Quote Originally Posted by mtndude23 View Post
    Something I always thought was a bit odd, everyone wants a lower BB, but then they run shorter cranks to keep from bashing them. But when you switch to a shorter crank you need to raise the seat to compensate-which then raises your center of gravity right? Which then kinda negates the benefits of a lower BB.
    The bike industry has decided everyone wants a lower bb, first thing I did on my new nomad was switch it to the high bb setting lol. Assuming you run a dropper post that is dropped going over anything techy then you still get the low bb benefits when standing up with the seat out of the way.

  99. #99
    meow, meow.
    Reputation: J. Random Psycho's Avatar
    Join Date
    Apr 2008
    Posts
    2,465
    Quote Originally Posted by Sparticus View Post
    I canít count the number of times Iíve climbed (cleaned) steep tech sections that my buddies on shorter cranks havenít and I credit my ability to mete power more, shall we say gently(?) because my cranks are a half-inch to an inch longer than theirs. No, Iím not making more power. Iím applying torque. And thatís the best argument Iíll make in favor of longer cranks. They apply torque differently.
    This. The difference between breaking and not breaking traction when climbing.
    26" rigid SS 4130 BB7 nylon-flats ESI latex-tubes non-lubricated-8spd

  100. #100
    mtbr member
    Reputation: kitejumping's Avatar
    Join Date
    Sep 2010
    Posts
    680
    Quote Originally Posted by J. Random Psycho View Post
    This. The difference between breaking and not breaking traction when climbing.
    Oval rings help a lot with that too if you're climbing loose stuff.

Page 1 of 2 12 LastLast

Members who have read this thread: 341

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

mtbr.com and the ConsumerReview Network are business units of Invenda Corporation

(C) Copyright 1996-2018. All Rights Reserved.