Results 1 to 20 of 20
  1. #1
    mtbr member
    Reputation: TiGeo's Avatar
    Join Date
    Jul 2008
    Posts
    2,898

    Looking at lighter cassettes, which on

    Thinking of replacing my cassette this year along with the chain and may as well shed some weight at the same time. I am not hard on my drivetrain so it should last a long time. Have a Sram PG-1030 which looks to be in the 380g range (correct me if I am wrong). Seeing the XG-1080 cassette at ~240g for ~$200 (eBay) isn't that bad and will shave over 100g. Don't have any interest in the $400 XX. What about Shimano XTR?

    Thanks
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  2. #2
    mtbr member
    Reputation: sfer1's Avatar
    Join Date
    Feb 2009
    Posts
    569
    One can get the XX cassette much cheaper than $400. You're not looking hard enough.

    Sram XG-1099 XX 10-fach Kassette - BIKE-COMPONENTS.DE

    199 euros - 19% VAT = 161 euros
    + 20 euros shipping
    TOTAL 181 euros (236 dollars)

  3. #3
    IllumaDucati
    Reputation: Roadsters's Avatar
    Join Date
    Jul 2008
    Posts
    512
    Since this is the Weight Weenies forum, I'm going to assume that your bike is reasonably light, and I'll also assume that you're in good shape and that you're not riding up mountains while carrying a forty-pound backpack.

    If this is the case, do you really need a 22-32 or 22-34 low gear? What for?

    For years I've been riding off-road with Dura-Ace 12-27 cassettes on my bikes. Everything about them is excellent. They're light, their machining is exceptional, and they shift beautifully.

    It's easy to find 27 or 28-tooth Dura-Ace 10-speed cassettes. That's what I'd suggest you try.

  4. #4
    mtbr member
    Reputation: TiGeo's Avatar
    Join Date
    Jul 2008
    Posts
    2,898
    I ride a 1x10 with a 33t front ring..I need an 11-36 mountain cassette. My bike with my dry condition tires sits around 23.5 and am hoping to get into the 22 range with a new cassette and a carbon bar. I may consider going to Eggbeaters to drop another 100g..but I swear by my SPDs and this falls into the "I don't care what they weight" category. I agree with your assessment; back in the day, the standard granny gear was a 24/28 or a 22/28 and they worked just fine.
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  5. #5
    IllumaDucati
    Reputation: Roadsters's Avatar
    Join Date
    Jul 2008
    Posts
    512
    The lower the number of teeth that contact the chain, the lower the amount of friction there is between them. If you try both, you will notice that it takes less energy to turn the cranks with (for example) a 22T driving a 27T than a 32T driving a 38T.

    For me at least, some of that old stuff just works better.

  6. #6
    mtbr member
    Reputation: limba's Avatar
    Join Date
    Jan 2004
    Posts
    2,911
    Don't buy any weenie Euro cassettes cause they don't shift and don't last. For every guy that says they work there's 5 that say they don't. Buy the lightest Shimano or SRAM cassette you can afford.
    You should post your bike specs if you haven't already. I bet there's better places than your drivetrain to knock off some weight.

  7. #7
    Rock and/or Roll
    Reputation:
    Join Date
    Dec 2005
    Posts
    425
    Quote Originally Posted by Roadsters View Post
    The lower the number of teeth that contact the chain, the lower the amount of friction there is between them. If you try both, you will notice that it takes less energy to turn the cranks with (for example) a 22T driving a 27T than a 32T driving a 38T.

    For me at least, some of that old stuff just works better.
    I'm gonna disagree with that statement. The friction gets higher when the tooth count goes down, because you are putting the same load force on the chain divided by less teeth. There's more stress on a 27 tooth cog vs a 34 tooth cog. More teeth engaged divides the load more.

    A 26/28 gear is the same as a 32/34, but there will be slightly less friction with the bigger gears.

    All that being said, I also use a road bike SRAM XX 11-28 cassette, and a superlight SRAM short cage rear derailleur, with a 42-26 double crankset. I just prefer the gear range with the smaller cassette, and I can still swap in the 11-32 cassette for more serious climbing.

    It's all personal preference, and the terrain that you ride on most of the time. If I were putting a SS together, I would prefer to run a gear ratio that uses the larger of the gear combos. Most people tend to go the WW route, and put on the smallest useable gears they can. It uses less chain links, and also gives you more ground clearance.

    In the end, the frictional difference is so small it doesn't make any noticeable difference to the rider, but the smaller gears and chain will wear out faster than the larger ones, since more load is placed on each tooth.

    You might want to look at lighter rims and tires for the biggest performance/weight improvement.

  8. #8
    mtbr member
    Reputation: TiGeo's Avatar
    Join Date
    Jul 2008
    Posts
    2,898
    As I said in my original post, I am looking at the SRAM XG 1080 or a Shimano...no weight weenie crap that doesn't work. No road cassettes.
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  9. #9
    Rock and/or Roll
    Reputation:
    Join Date
    Dec 2005
    Posts
    425
    Quote Originally Posted by TiGeo View Post
    As I said in my original post, I am looking at the SRAM XG 1080 or a Shimano...no weight weenie crap that doesn't work. No road cassettes.
    I would be looking for an XTR or SRAM XX cassette if I were you. Just search for a good deal, and be patient til you find one. I tried a full titanium cassette before, but the shifting performance wasn't as good as Shimano or SRAM. Nothing worse than blowing a shift at the wrong time...

  10. #10
    > /dev/null 2&>1
    Reputation:
    Join Date
    Feb 2012
    Posts
    971
    Quote Originally Posted by turbogrover View Post
    I'm gonna disagree with that statement. The friction gets higher when the tooth count goes down, because you are putting the same load force on the chain divided by less teeth. There's more stress on a 27 tooth cog vs a 34 tooth cog. More teeth engaged divides the load more.

    A 26/28 gear is the same as a 32/34, but there will be slightly less friction with the bigger gears
    Actually, I think the net force of any friction (along the vector of pull of the chain) will be the same for both small gears and large. If i remember correctly (its been a few years), the equation for static friction should apply here because the chain isn't sliding on the gears once its engaged. So the force of friction of any one link on any one tooth is something like

    F of friction = sum of force perpendicular to the engagement surface X coefficient of friction for the metal on metal

    This F added across all teeth must equal the force of your pedaling, if it didn't, the chain would be sliding on the cogs.

    So, if you had your pedaling force distributed across 10 vs 20 teeth, the force on each tooth is exactly halved. So the friction (of chain on teeth) i think may be the same no matter how many teeth. And its that friction which helps keep the chain on the cogs. You're not losing energy to heat really because its not sliding metal on metal. Its 'good' friction. For example if you can imagine a cassette with very shallow, short teeth, you can also visualize that it would be easier for pedaling force to overcome the total force of friction and slide the chain on the cogs.

    Now, there may be some friction loss in chain sliding on chain, as it wraps around the cogs, which seems like a zero sum game too: for the small cog, you have fewer links grinding against each other at larger angles of rotation, vs more links going through smaller angles of rotation for a bigger cog. Feels like that's par for the course too, but i could be wrong

    In the end, the frictional difference is so small it doesn't make any noticeable difference to the rider, but the smaller gears and chain will wear out faster
    So, long winded way of agreeing with your final statement: the friction loss is par for the course and the wear is the main driver.
    ------------------------------------------------
    They're justified and they're ancient and they like to roam the land

  11. #11
    mtbr member
    Reputation: madsedan's Avatar
    Join Date
    Aug 2010
    Posts
    1,426
    I got a hook-up on a new XX cassette and its the nicest one I've ridden yet. I've not had an XTR and I may try that the next time I buy one but mine shifts super nice and is crazy light.
    Hardrock 29er, Niner EMD9, Cannondale F29, Camber Expert, 650b Nickel all gone.
    2014 Giant Anthem 27.5 here.

  12. #12
    mtbr member
    Reputation: bholwell's Avatar
    Join Date
    Oct 2007
    Posts
    2,059
    Quote Originally Posted by ddprocter View Post
    Actually, I think the net force of any friction...
    You're missing a few a few things. Here's some light reading on the subject: http://www.g-cog.com/VBMX/spicer.pdf
    Tire Design & Development Engineer. The opinions expressed in this forum are solely my own.

  13. #13
    > /dev/null 2&>1
    Reputation:
    Join Date
    Feb 2012
    Posts
    971
    That's a good read, thanks for sharing -

    So in conclusion:
    -Chain loss occurs primarily at engagement and disengagement points on the chainring and cassette respectively, on the tension-side of the chain
    - Counter-intuitively, they conclude that the primary mode of loss is not friction but rather the following:

    "Most probably, mechanical losses that are not converted to thermal energy in the drive account for the remainder of the measured loss. These mechanical losses most likely are low frequency vibrations( < 100 kHz) that are damped by the overall structure and do not produce localized heating in the drive train."


    -They found that larger sprockets are more efficient than smaller sprockets, because "For a given drive rotation rate, larger sprockets will produce fewer of these events per unit time and thereby incur less loss. It is likely that higher chain tensions restrict the link motion during engagement and also reduce the associated losses."

    However, the test compares the efficiency of a 52-21 chainring/cog combination with a 52-11 combination, which is not a real world scenario, because this is not a tradeoff that a typical bicyclist is interested in. A better comparison would be two gear combinations which result in similar leverage ratios, but with different combinations of larger/smaller chainring/cassette gear, for example an 26-36 and a 22-34 - because this answers the question of whether its more efficient to invest in smaller cogs or smaller chainrings. Since the primary mode of loss is mechanical losses/low speed vibration, which is a function of how frequently the chain engages and disengages teeth, it feels like the total loss would be about the same for similar combos like the above.

    It would be interesting to run the calcs and tests with a real world scenario such as this, I hope someone does or did

  14. #14
    mtbr member
    Reputation: veritechy's Avatar
    Join Date
    Jan 2008
    Posts
    600
    Quote Originally Posted by Roadsters View Post
    The lower the number of teeth that contact the chain, the lower the amount of friction there is between them. If you try both, you will notice that it takes less energy to turn the cranks with (for example) a 22T driving a 27T than a 32T driving a 38T.

    For me at least, some of that old stuff just works better.
    totally agree. I have a DA 12-27 9 speed. It's less than 180g.

  15. #15
    mtbr member
    Reputation: veritechy's Avatar
    Join Date
    Jan 2008
    Posts
    600
    Quote Originally Posted by TiGeo View Post
    I ride a 1x10 with a 33t front ring..I need an 11-36 mountain cassette. My bike with my dry condition tires sits around 23.5 and am hoping to get into the 22 range with a new cassette and a carbon bar. I may consider going to Eggbeaters to drop another 100g..but I swear by my SPDs and this falls into the "I don't care what they weight" category. I agree with your assessment; back in the day, the standard granny gear was a 24/28 or a 22/28 and they worked just fine.
    SPD's feel so much better. I have eggbeaters also, but I cannot unclip easily on those. I also have the xpedo Ti's. They also use SPD cleats but are only 230g. You also get the nice click that lets you know you are clipped in.

  16. #16
    mtbr member
    Reputation: Hand/of/Midas's Avatar
    Join Date
    Sep 2007
    Posts
    2,679
    Quote Originally Posted by ddprocter View Post


    -They found that larger sprockets are more efficient than smaller sprockets, because "For a given drive rotation rate, larger sprockets will produce fewer of these events per unit time and thereby incur less loss. It is likely that higher chain tensions restrict the link motion during engagement and also reduce the associated losses."

    However, the test compares the efficiency of a 52-21 chainring/cog combination with a 52-11 combination, which is not a real world scenario, because this is not a tradeoff that a typical bicyclist is interested in. A better comparison would be two gear combinations which result in similar leverage ratios, but with different combinations of larger/smaller chainring/cassette gear, for example an 26-36 and a 22-34 - because this answers the question of whether its more efficient to invest in smaller cogs or smaller chainrings. Since the primary mode of loss is mechanical losses/low speed vibration, which is a function of how frequently the chain engages and disengages teeth, it feels like the total loss would be about the same for similar combos like the above.

    It would be interesting to run the calcs and tests with a real world scenario such as this, I hope someone does or did
    Well, given the study i would assume the 26-36 would be slightly more efficient given the greater quantity of teeth. Realistically it would be negligible to the point that part availability, weight, and aesthetics would be more important.
    Disclaimer:I work in a Bike Shop.http://www.northcentralcyclery.com/

  17. #17
    mtbr member
    Reputation: roaringboy's Avatar
    Join Date
    Aug 2009
    Posts
    194
    Quote Originally Posted by veritechy View Post
    SPD's feel so much better. I have eggbeaters also, but I cannot unclip easily on those. I also have the xpedo Ti's. They also use SPD cleats but are only 230g. You also get the nice click that lets you know you are clipped in.
    Just started using Egg Beaters after having SPD's for years - clicking out isn't the problem (i actually find them quite easy to get out of), it's managing to click in! Although i guess it's just a matter of practice.

  18. #18
    ups and downs
    Reputation: rockyuphill's Avatar
    Join Date
    Nov 2004
    Posts
    13,651
    Quote Originally Posted by roaringboy View Post
    Just started using Egg Beaters after having SPD's for years - clicking out isn't the problem (i actually find them quite easy to get out of), it's managing to click in! Although i guess it's just a matter of practice.
    Eggbeaters require a certain Zen approach, the harder you try to clip in the harder it is to do, if you just step down to put your foot where it should be they will click in like a breeze.
    I'm a member of NSMBA and IMBA Canada

  19. #19
    mtbr member
    Reputation: TiGeo's Avatar
    Join Date
    Jul 2008
    Posts
    2,898
    Quote Originally Posted by rockyuphill View Post
    Eggbeaters require a certain Zen approach, the harder you try to clip in the harder it is to do, if you just step down to put your foot where it should be they will click in like a breeze.
    Actually, I think at some point, I will just drop ~70g and go with XTR SPDs. The 520 are boat anchors but are bullet proof!
    Geologist by trade...bicycle mechanic (former) by the grace of God!

    2012 Specialized Stumpy EVO 29 HT

  20. #20
    Get to dah choppah
    Reputation: icsloppl's Avatar
    Join Date
    Nov 2012
    Posts
    144
    Ti cogs, as on the XTR, tend to wear more quickly but not break or bend.
    Al cogs, as on the SRAM models, do.

    If you're looking for good reliability, go XTR. The SRAM's weigh a bit less, but the tradeoff may be a poor one.
    Santa Cruz TBc
    Pivot 429c

Posting Permissions

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