Q's about 2x9 (12-34) vs. 3x9 (12-27)- Mtbr.com
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  1. #1
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    Q's about 2x9 (12-34) vs. 3x9 (12-27)

    I'm sure this has been discussed here before, but the search function keeps screwing up, so... here it is:
    Which of these two setups works the best and saves more weight(from your real world experience, hopefully)? Should I slap on an Ultegra 12-27 and leave the front 3 rings, or should I keep the 12-34 cassette and go 2 rings up front?
    Another question, it seems like most people's 2x9 setups keep the outer and middle ring. Wouldn't it make more sense from a weight standpoint to ditch the outer and keep the middle and inner chainring? I know you don't get the higher gear, but you could put a 40 tooth middle with a 24 tooth granny, along with an 11 tooth cassette, and get a similar top end to a 44 x 12. Let me know the deal, por favor!
    -Sean

  2. #2
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    12-27: less weight + better gear selection

    Quote Originally Posted by sean350
    I'm sure this has been discussed here before, but the search function keeps screwing up, so... here it is:
    Which of these two setups works the best and saves more weight(from your real world experience, hopefully)? Should I slap on an Ultegra 12-27 and leave the front 3 rings, or should I keep the 12-34 cassette and go 2 rings up front?
    Another question, it seems like most people's 2x9 setups keep the outer and middle ring. Wouldn't it make more sense from a weight standpoint to ditch the outer and keep the middle and inner chainring? I know you don't get the higher gear, but you could put a 40 tooth middle with a 24 tooth granny, along with an 11 tooth cassette, and get a similar top end to a 44 x 12. Let me know the deal, por favor!
    -Sean
    2x9 needs powerful legs! jumps from one gear to the next are pretty big so you need the power to pedal and the usually missing granny ring doesn't help on steep climbs either. your idea with the different chainring setup is going in the right direction but overall such a setup is still heavier than

    3x9 with 12-27 cassette:
    cassette: Dura Ace 180g / Ultegra 230g......XTR 11-34= 242g.... go for the DA -60g !!
    shorter chain with 12-27cassette........................................ ...........................-20g
    Aluminium 20t granny and Al-bolts............................................. ...................+20g
    short cage Dura Ace derailleur 180g...old XTR 235g/ new XTR 200g/ X.O 198g..-20-55g

    overall savings with 3x9 (12-27) depending your parts choice is up to 115g

    by the way - there's triple rings out there that weigh less than your typical Shimano double ring setup: Extralite or TA Specialite have rings that weigh as little as 115g all together. rememeber a 44t XT weighs already 85g, a 32t is 45g.

    the 12-27 cassette has the gears spaced much closer. this is like having "semi-gears" compared to a usual MTB cassette. it allows you to keep your cadence which is a big plus on climbs. you end up beeing faster as you can adjust the gears according to your power. a MTB cassettes big gaps often lets you remain in a lower gear as the next one would already be too much effort....the closer spaced cassette allows you to do one more shift and this makes you faster, it requires MORE shifting compared to a MTB cassette. this needs some getting used to at first but as i said the constant cadence and faster speeds will convince you and you really get accustomed in no time.

    by having a 20t granny in the front you regain the lost low gear. 20/27 equals 22/30 which should be low enough.

    definitely go with the DA cassette and derailleur! there's too much savings there! and the shorter derailleur makes for precise shifts and is also less likely to be damaged or bent because of it's compact size.
    Last edited by nino; 08-06-2005 at 10:06 PM.

  3. #3
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    Quote Originally Posted by sean350
    I'm sure this has been discussed here before, but the search function keeps screwing up, so... here it is:
    Which of these two setups works the best and saves more weight(from your real world experience, hopefully)? Should I slap on an Ultegra 12-27 and leave the front 3 rings, or should I keep the 12-34 cassette and go 2 rings up front?
    How heavy is your 12-34 ??

    I haven't had a lot of experience with this but have just built up a 2x9 setup and had the same questions to work out. I found the variables to be huge and unless you're careful with part selection you will save little weight. My 2x9 setup was decided when I got a light (236g) 12-34 XTR cassette with a near new race wheelset.

    I checked out the WW site and crunched some numbers against my XTR.

    Ultegra 12-27 cassettes - 223-231g ..saving of 5-13g
    Dura-ace 12-27 cassette - 178g ... saving of 58g

    Taking into account the saving of dropping my 22T ring and bolts (28g) I would be looking at a weight "gain" of 15-23g going with Ultegra and a saving of 30g with Dura-ace. Maybe I would have got a Dura-ace if I had no cassette but figured it wasn't worth the cost since I had the XTR. I also saved weight with a shorter BB to improve the chain line for the 2x9 so I'm at least even or a little ahead in the weight savings.

    Quote Originally Posted by sean350
    Another question, it seems like most people's 2x9 setups keep the outer and middle ring. Wouldn't it make more sense from a weight standpoint to ditch the outer and keep the middle and inner chainring? I know you don't get the higher gear, but you could put a 40 tooth middle with a 24 tooth granny, along with an 11 tooth cassette, and get a similar top end to a 44 x 12. Let me know the deal, por favor!
    -Sean
    You may get a better answer from the more knowledgeable here but my thoughts are we are getting into hair splitting territory. DH bikes use the two inner rings and use longer BB to improve the chain line, So your losing grams with a longer BB and I haven't seen many weight weenie DH BB's . Also the granny ring uses separate bolts (more weight) and the middle and outer ring share the same bolts (weight saving).

    EDIT: I agree with Nino's post, that is "if" your going to do a full make over on your drivetrain. My post is just from a cassette change and dropping the granny POV only, if your going for a ground up build a full Dura-ace rear and light weight chain rings (3x) up front is going to be hard to beat in weight and versatility.
    Last edited by Laika; 08-06-2005 at 11:48 PM. Reason: to add stuff

  4. #4
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    switching back to 11-32

    I'm just about ready to forget about 12-27 cassettes. The only place where the road cassette really helps is on very long climbs. But here, the terrain is changing too quickly and it is easy to get caught in the wrong gear because of all the shifting that is required. Getting caught in the wrong gear is a real problem since using a road cassette makes your legs too specialized so they only work in a narrow cadence range. So, with the road cassette there is a tendancy to be pedaling too fast coming over a hill and pedaling too slow going back up since you can't keep up with the shifting. You can't even put the power down properly because of this and constantly shifting...you are actually losing momentum! ...I'm doing more shifting than pedaling sometimes. My shifter is going to wear out before my chain and chainrings.

    I did it for the all the weight savings and closer gear ratios but after many races like this, I can see that it just doesn't make sense for off-road. To be fast off-road, your legs need to be versatile and be able to work at a range of cadences. Another nice thing about the 11-32 is that you can stay in the middle ring almost exclusively except on the toughest climbs ....you always have to drop down to your granny sooner when using a road cassette so it's not just crazy shifting at the back but at the front as well.

    Here's a question:

    will my RD-7800 work fine with an 11-32 cassette?

  5. #5
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    2 x 9 Benefits!

    I swithed to a middleburn Duo using 29 and 44 Rings. This might not be the lightest setup however when I am Mountain Biking I rarely if ever switch out of the 29 ring. That is very few front deraileur shifts. This is the main advantage IMHO.

  6. #6
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    Depends on your terrain

    I've been riding 2x9 (29-44 x 11-32) for years. I switched to 2 x 9 because it better suited the terrain I ride. To me, the (minimal) weight savings was just a bonus to the performance value of having a setup that better suited the terrain I ride. Living in Wisconsin, I had absolutely no use for a 22t front chainring. However, since I've been riding this 2x9 setup I've taken the bike to CO & UT and have been able to ride everything Moab and Winter Park could throw at me.

  7. #7
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    Road cassette's in the long run don't make you better riders. It kill the souplesse of your legs, capacity to accellerate by revving up rather than gearing up.
    I've had great race season on 12-27, but I'm planning to go 11-34 and even 4-5 spd. Small cassette with double the gaps of an MTB cassette. If singlespeeders can be fast, then 4-5spd is plenty. Also allows use of singlespeed hubs which make for a stronger dishless rear wheel.

  8. #8
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    Quote Originally Posted by Lothar Othp
    I've been riding 2x9 (29-44 x 11-32) for years. I switched to 2 x 9 because it better suited the terrain I ride. To me, the (minimal) weight savings was just a bonus to the performance value of having a setup that better suited the terrain I ride. Living in Wisconsin, I had absolutely no use for a 22t front chainring. However, since I've been riding this 2x9 setup I've taken the bike to CO & UT and have been able to ride everything Moab and Winter Park could throw at me.
    It definitely depends on the terrain, and also your riding style. In my case, I started off with 22-32-44, and 12-34. The terrain here has a lot of steep climbs that require the granny gear. But coming down, the trails are too twisty and technical to ever have enough speed to get in the big ring. I only used the big ring once in a while if I had to ride the road a bit to get to a trail. So I dropped the 44, and replaced the 32 with a 34. When the cassette wore out I replaced it with an 11-34. I saved a bit of weight, and gained a lot of clearance for going over logs, and almost never spin out my biggest gear. But that's just what works for me, and where I ride.

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    after taking your big ring off, wasn't your chain coming off when shifting from the granny up to the middle on bumpy terrain even after limiting the front derailleur? I removed mine and the chain would come off so the 42t had to go back on even though the chain is now shortened and I still don't shift up to that ring...


    Cloxxki, will a DuraAce RD-7800 rear derailleur accomodate an 11-32 XT cassette?

  10. #10
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    Quote Originally Posted by Laika
    How heavy is your 12-34 ??

    I haven't had a lot of experience with this but have just built up a 2x9 setup and had the same questions to work out. I found the variables to be huge and unless you're careful with part selection you will save little weight. My 2x9 setup was decided when I got a light (236g) 12-34 XTR cassette with a near new race wheelset.

    I checked out the WW site and crunched some numbers against my XTR.

    Ultegra 12-27 cassettes - 223-231g ..saving of 5-13g
    Dura-ace 12-27 cassette - 178g ... saving of 58g

    Taking into account the saving of dropping my 22T ring and bolts (28g) I would be looking at a weight "gain" of 15-23g going with Ultegra and a saving of 30g with Dura-ace. Maybe I would have got a Dura-ace if I had no cassette but figured it wasn't worth the cost since I had the XTR. I also saved weight with a shorter BB to improve the chain line for the 2x9 so I'm at least even or a little ahead in the weight savings.



    You may get a better answer from the more knowledgeable here but my thoughts are we are getting into hair splitting territory. DH bikes use the two inner rings and use longer BB to improve the chain line, So your losing grams with a longer BB and I haven't seen many weight weenie DH BB's . Also the granny ring uses separate bolts (more weight) and the middle and outer ring share the same bolts (weight saving).

    EDIT: I agree with Nino's post, that is "if" your going to do a full make over on your drivetrain. My post is just from a cassette change and dropping the granny POV only, if your going for a ground up build a full Dura-ace rear and light weight chain rings (3x) up front is going to be hard to beat in weight and versatility.
    No one's talked about the weight saving with 2x9 by enabling a true road front derailleur. Most mountain fron Ds are pretty heavy relative to road versions. I run an older 7700 front der with my 2x9.

    Benefits of 2x9 that haven't been mentioned:

    1. lighter potential weight with a road front derailleur (provided you have a bottom pull mount)

    2. better Q factor. You run a narrower BB bracket. This is underappreciated, particularly as external bearing thee rings cranks continue to push the Q factor wider. I have narrower hips, and I like a mountain bike drivetrain that replicates by road geometry. The power from my hips to the pedals is close to a straight line. On wider cranksets, I notice my ankles like to turn inward to compensate for the wider stance.

    3. Fewer front shifts. If given the option, I think it's much better to change gearing with a rear cluster than by shifting front chainrings. On some race course with continuous up and downs, it's nice having a middle ring that can serve for climbing and descending. With longer climbs or less abrubt ups and downs, having the simplicity of two rings is better. There less to think about - I'm either in a big ring for flats or descending, or the small for climbing.

    4. More intuitive, less to think about. I made the mistake on my three ring dual sus bike of leaving it in the big ring on this long descent at Downieville. I forgot about it when there was a short climb, and didn't have the gearing to avoid a dismount and run. My mistake, but I probably could've just geared down with a 12-34 or 12-32 and cleared it. Not enough gearing with my 12-27.

    I run both, a 2x9 with and 11-32, and a three chainring with a 12-27 and I think I'm gravitating more towards the 2x9 with my newer bike. I wanted to try a traditional three chainring with a roadie cassette.

  11. #11
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    isn't it a given to use a road FD for weight savings whether you use a double or triple setup? The only requirement is that your frame can accomodate it (ie. bottom pull).

    I'm just referring to nino using a road FD on his triple setup...

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    all benefits with triple too...

    Quote Originally Posted by Patchito
    No one's talked about the weight saving with 2x9 by enabling a true road front derailleur. Most mountain fron Ds are pretty heavy relative to road versions. I run an older 7700 front der with my 2x9.

    Benefits of 2x9 that haven't been mentioned:

    1. lighter potential weight with a road front derailleur (provided you have a bottom pull mount)

    2. better Q factor. You run a narrower BB bracket. This is underappreciated, particularly as external bearing thee rings cranks continue to push the Q factor wider. I have narrower hips, and I like a mountain bike drivetrain that replicates by road geometry. The power from my hips to the pedals is close to a straight line. On wider cranksets, I notice my ankles like to turn inward to compensate for the wider stance.

    3. Fewer front shifts. If given the option, I think it's much better to change gearing with a rear cluster than by shifting front chainrings. On some race course with continuous up and downs, it's nice having a middle ring that can serve for climbing and descending. With longer climbs or less abrubt ups and downs, having the simplicity of two rings is better. There less to think about - I'm either in a big ring for flats or descending, or the small for climbing.

    4. More intuitive, less to think about. I made the mistake on my three ring dual sus bike of leaving it in the big ring on this long descent at Downieville. I forgot about it when there was a short climb, and didn't have the gearing to avoid a dismount and run. My mistake, but I probably could've just geared down with a 12-34 or 12-32 and cleared it. Not enough gearing with my 12-27.

    I run both, a 2x9 with and 11-32, and a three chainring with a 12-27 and I think I'm gravitating more towards the 2x9 with my newer bike. I wanted to try a traditional three chainring with a roadie cassette.
    1. me too i use a roadie f-der with my triple setup

    2.i also run a short "roadie"axle lenght with my triple setup (103mm square)

    3.correct - in constant up/down situations the 12-27 isn't ideal. i was referring to longer climbs where the narrower spaced gears allow for higher speeds, are less fatiguing, less tiring...

    4.me too i have "intuitive" shifting. it's all about getting used to it. i just wonder why roadbikes have the gears spaced so close??? because the closer the gears the more effective you can bring your power to the ground. why should they have 11-21 10-speed cassettes when you could live with just 5 gears? hmmmm....if you've ever ridden a roadbike you know that spinning the legs is the key.

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    Quote Originally Posted by nino
    i just wonder why roadbikes have the gears spaced so close??? because the closer the gears the more effective you can bring your power to the ground. why should they have 11-21 10-speed cassettes when you could live with just 5 gears? hmmmm....if you've ever ridden a roadbike you know that spinning the legs is the key.
    nino, roadbikes having such close gearing because the changes in gradient are significantly less frequent. Then, having close gearing makes all the difference in the world because you hardly shift as often as in MTB.

    I don't think it's a good thing to use a road cassette because it changes the physiology of your legs - all your fast twitch muscle fibres disappear and changes are made to neuron arrangement. You develop a tiny powerband like an F1 engine so you can only develop optimum power at a certain cadence and are useless if you fall out of that small range. Let's think about this - how many XC World Cup riders are using 12-27 cassettes instead of 11-32 or 11-34?

  14. #14
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    my vote is for 12-27

    I use 20/29/42 x 12-27 on my race bike and would like to use it on my trail bike too. with DA components it make the rear of the bike soo light. The only reason I can think of to go 2x9 is to get better chainline. A nice feature of small gears accross the board is that the distance the chain has to bend is maximized. So, I can fully cross the chain when needed (I only go 42x27, never 20x12). As far as the road gearing tuning my legs for a narrow range I certainly have never noticed that affect and acutally I find myself spinting out of the saddle more with a road cassette. The difference between 12-27 and 11-32 is not that much, but I do notice that I can click to the next taller gear when cresting a hill much sooner with 12-27 than with 11-32. See attached some gear info for my setup compared to a standard setup. I may plug in your 2x9 setup for comparison or you can create it yourself.



    Personally, if you are going to go 2x9, then go all the way and go 1x9 - that will really save some weight and complexity. An 11-34 cassette has a range of 3.1, compared to my race setup which has a range of 4.7 - the difference is not that great; a 2x9 setup would have a range of about 3.9. A range of 3.1 is equivalent to using only the lower half of the cassette while in my big ring.
    Attached Images Attached Images
    Last edited by Motivated; 08-08-2005 at 04:09 PM. Reason: added image
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    Quote Originally Posted by Motivated
    As far as the road gearing tuning my legs for a narrow range I certainly have never noticed that affect and acutally I find myself spinting out of the saddle more with a road cassette.
    If you find yourself sprinting out of the saddle more with a road cassette, it is because you are having to stand up whenever you're not quite in the "perfect" gear because you have a smaller powerband and that is the only way to try and stay in your optimum cadence range.

    Using a road cassette, means your torque goes out the window. Like a F1 car with 900 hp and 250 lb.ft of torque. It's ok for them because they have very close ratio gearing to suit the tracks they race on.

    In MTB, you NEED torque (like a diesel engine) not only for the constant up and downs but out of every slow, tight corner. Torque doesn't matter on the road but in MTB, you constantly scrub off speed (momentum) and even stop pedaling in certain sections. When you resume pedaling and try to accelerate, the torque is what gets you from corner to the next corner. If you're having to shift more between those corners because you have a special cadence that you need to be able to ride, then you are not effectively putting the power to the cranks and thus your rear wheel. You're effectively gliding and not efficiently maintaining momentum and ultimately wasting energy.

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    I'm going to give the 12-27 a try. Do you guys usually suggest changing the middle ring from 32 to a 29 or 30? I was going to put a 20 granny and leave the 32 in the middle. Is that make the gap too big between the granny and middle?

    Thanks for the input.

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    You'll hardly notice the 32 vs a 30t imo. Also, to gain back some overlap, stick an 11t cog(don't forget to use an 11t lockring) on it, and drop the 14t. Now you'll have 11-12-13-15-17...and so on. This gives back some of the overlap your losing.

    I race a 42-31(yes 31t)-20t with an 11-27DAce cassette atm.

  18. #18
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    Quote Originally Posted by nino
    1. me too i use a roadie f-der with my triple setup

    2.i also run a short "roadie"axle lenght with my triple setup (103mm square)

    3.correct - in constant up/down situations the 12-27 isn't ideal. i was referring to longer climbs where the narrower spaced gears allow for higher speeds, are less fatiguing, less tiring...

    4.me too i have "intuitive" shifting. it's all about getting used to it. i just wonder why roadbikes have the gears spaced so close??? because the closer the gears the more effective you can bring your power to the ground. why should they have 11-21 10-speed cassettes when you could live with just 5 gears? hmmmm....if you've ever ridden a roadbike you know that spinning the legs is the key.
    If I've ever ridden a road bike? Gosh, your arrogance does get a bit much sometimes.

    I would opine that the narrower spacing on a road cassette is especially usefull in a higher speed peleton, where riders are making constant and slight adjustments to their speed as they respond the the riders in front of them, headwinds, and changes in terrain. It's more about maintaining momentum and cadence..basically being smooth. When I ride my road bike by myself and I don't have to respond to other riders I maybe shift once or twice....the entire ride!

    Agree with Eurorider to an extent that MTB racing requires more torque to be applied to the pedals, a generally lower cadence, and a greater need for the ability to apply high force. I dunno about you, but I'm not "spinning the legs" much on my road bike when the grade exceeds 10% and my smallest gear is 39x21.

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    Quote Originally Posted by Duckman
    You'll hardly notice the 32 vs a 30t imo. Also, to gain back some overlap, stick an 11t cog(don't forget to use an 11t lockring) on it, and drop the 14t. Now you'll have 11-12-13-15-17...and so on. This gives back some of the overlap your losing.

    I race a 42-31(yes 31t)-20t with an 11-27DAce cassette atm.
    Thanks for the info Duckdude!
    I have taken out the 14 and put in the 11 for....DH racing. I have never used the 12-27 on the xc bike however.....I don't find I use the 11 very much during xc races so I might not bother swapping out. I'm really after tighter ratios for long fireroad climbs. I find for 10min to 1hr climbs I am finding the gaps on my 12-34 pretty huge. I think I can lay down more power if I was running an an optimal rpm. Short races I tend to lug it if I can't get the optimal cadenance and sacrifice my endurance; long races I tend to spin to favor endurance and fend off cramping...but I found that I cannot produce as much power spinning at a higher than normal cadence over the long haul...my inherent blood anaemia is my weakest link.
    I got a Salsa Bandito last week and I am going to build it up and race it this weekend; it weighed 1260grams for 16"...pretty good I thought. I am looking forward to comparing it to my specializied epic. You guys are too influential

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    sorry...

    Quote Originally Posted by Patchito
    If I've ever ridden a road bike? Gosh, your arrogance does get a bit much sometimes.

    I would opine that the narrower spacing on a road cassette is especially usefull in a higher speed peleton, where riders are making constant and slight adjustments to their speed as they respond the the riders in front of them, headwinds, and changes in terrain. It's more about maintaining momentum and cadence..basically being smooth. When I ride my road bike by myself and I don't have to respond to other riders I maybe shift once or twice....the entire ride!

    Agree with Eurorider to an extent that MTB racing requires more torque to be applied to the pedals, a generally lower cadence, and a greater need for the ability to apply high force. I dunno about you, but I'm not "spinning the legs" much on my road bike when the grade exceeds 10% and my smallest gear is 39x21.
    sorry - that wasn't supposed to be arrongant!

    fact is that the bigger spaced MTB cassette means more effort for your body. it's a completely different story for pro-riders as these ARE powerful riders with strong legs and they have to care for the rather short race-lenght only. they train their legs for that rather short riding and accept the fact that they actually overrev.

    all i tried to say about "improved" gearing with a 12-27 cassette has been experienced by EVERY rider out there almost every day:

    MTB-cassette rider:
    you are doing an uphill in a certain gear. heartrate pretty high at about the aerobic/anaerobic boarder.... you won't shift to the next taller gear as this would mean your legs will get sour, your heartrate goes up to thew moon and maybe you will be forced to downshift just a few seconds later 'cause the next gear is already too much effort...you already know your limits and know that the next gear would be too much.

    now the same situation with the 12-27 cassette, lets go at the SAME speed, SAME cadence...so we have the SAME torque,SAME power needed for that specific uphill:
    you are in a certain gear, let's say you are riding next to your shadow who still rides the MTB cassette...the difference is that you can actually shift to the next higher gear. your speed goes up, your heartrate too but maybe just as little that you still aren't entering into "overrev". you will be able to pull that gear as it is still an effort you can do without going over your limiter.

    so what happens? you are pulling away from your shadow...

    i completely understand your arguments about needing versatile legs etc...but fact is that especially on uphills and fast continous streches the narrow gears allow for higher speeds. that a MTB-rider has to have torque and low and high cadences is correct. but the perfect gears help you bring your power to the ground and let your body work in his "best range". you can still do low/high frequency riding! just don't shift

    that said:
    i wouldn't use my setup in Sedona for example where behind every corner or bush the trail goes up or down forcing you to shift constantly even with a MTB-cassette. with a DA cassette you would be shifting all the time and often you would be catched by surprise and find yourself in a too low or too high gear....too much shifting especially in the front isn't what we are looking for . therefore it's really the type of riding/terrain each one has that allows for the use of one or the other cassette.

    lately i used my full-rigid "winterbike" for all my trailriding. it has 48-36-26 mated to a 11-32 cassette. i usually ride all trails in the middle ring and hardly ever have to shift in the front. i agree it's nice not to think about chainging gears that much but i pretty often find myself wishing for a gear "in between"... i need those big rings up front because i have a second set of wheels for road-riding with a 11-21 cassette.
    Last edited by nino; 08-08-2005 at 11:23 PM.

  21. #21
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    While I agree that both setups have there pro's and con's and every rider after trying both systems will prefer one or the other this theory about using a road cassette will make for a weaker MTB rider is laughable IMO.

    Think about it, what has really changed going to a roadie cassette? even a 11-21? all you are missing out on is that 21-34 range in the granny gear... nothing more, nothing less. There is plenty of ratio overlap in the 44/32 rings with a roadie cassette so your not missing out on any gears except for the nastiest of climbs when you run short in that granny ring and on the up side you have lots of in between gear ratios that you don't have with a MTB cassette.

    The way I looked at the setup if I went with a 3 ring & roadie cassette was that I would be doing a more shifting with the front rings and skipping gears in the back at times so I was getting changes that are same as using a MTB cassette. I also would get the benefit of the close ratios when attacking smooth climbs seated so I can keep my legs spinning where the are producing the most power for the least effort (if you know what I mean). If you are using twist shifters the number of gears you change at once are of no consequence, you can change all nine at once in one big twist if you like. Just because you have lots of close ratio gears doesn't mean you have to use them all the time.

    Surely being a fast rider is about being strong, and just as importantly smart in the application of that power.
    Last edited by Laika; 08-09-2005 at 04:23 AM. Reason: typo

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    Will your RD7800 work with a 11-32 casette? Nope.

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    I ran a 1X9 with a 36t chainring, and an 11-34 cassette on my race bike, but found that needed a higher gear for some of the faster fireroad sections. So I switched to a 32-44, with an 11-32 cassette, and have liked that setup a lot. The 1X9 is nice for it's simplicity, but for racing the top gear isn't there. The 36/ 11-34 is now on my trail bike.

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    Quote Originally Posted by eurorider
    after taking your big ring off, wasn't your chain coming off when shifting from the granny up to the middle on bumpy terrain even after limiting the front derailleur? I removed mine and the chain would come off so the 42t had to go back on even though the chain is now shortened and I still don't shift up to that ring...
    I did have some problems with that at first, but it hasn't happened in a while. I spent a good bit of time getting the front derailleur adjusted properly (or at last as good as I could get it). I think I'm also a little more careful when I shift out of the granny now too - not spinning the cranks quite as fast, and not twisting the grip shifter quite as quickly as I used too. It also probably helps that I've gotten myself in much better shape over the last few months, so I'm not using the granny gear as much as I used to.

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    you are taking a huge leap

    I sprint more with 12-27 because my legs are fresher and I have the energy to really gun it over the top of a climb or up short climbs. XC racing is largely about climbing, which is why we try to make our bikes light, jack our seats up above the bars and why I generally tune my bike for climbing performance.

    F1 cars don't have particularly tight gearing. Remember, their race speeds range from 50 to 200mph and they have 7 gears. Watch their rev ranges and they typically go from about 10,000-12,000 rpm to 19,000 rpm, shift and drop down to 12,000 rpm. They often come out of corners down in the 10,000 - 12,000rpm range. That is similar gearing to my Honda Accord which drops from about 5,000 to 3,500 rpm on upshifts.

    You think small shifts up are bad, I look at it the opposite way - big shifts down are bad. Either way, you don't have to shift. Sometimes the gearing of a 12-27 looks much different than an 11-32, but the difference is actually only a small change in cadence. Shifting 2 clicks on 11-32 is equivalent to shifting 2 clicks on a 12-27 and adjusting cadence by 3-5rpm. So in some ways, tighter gearing can force you to extend your rpm range.

    Shifting should be encouraged - it means you are accelerating. I feel much more confident grabbing that next gear knowing it isn't a huge leap for my already tired legs. Human muscles are sensitive to near limit exertion. We are not gas engines (well, my wife might disagree) and our legs fatigue largely due to the amount of high force we put out. If you can reduce those high forces you should because it will extend your endurance.

    I have also attached a graph which goes with the table from above.





    Quote Originally Posted by eurorider
    If you find yourself sprinting out of the saddle more with a road cassette, it is because you are having to stand up whenever you're not quite in the "perfect" gear because you have a smaller powerband and that is the only way to try and stay in your optimum cadence range.

    Using a road cassette, means your torque goes out the window. Like a F1 car with 900 hp and 250 lb.ft of torque. It's ok for them because they have very close ratio gearing to suit the tracks they race on.

    In MTB, you NEED torque (like a diesel engine) not only for the constant up and downs but out of every slow, tight corner. Torque doesn't matter on the road but in MTB, you constantly scrub off speed (momentum) and even stop pedaling in certain sections. When you resume pedaling and try to accelerate, the torque is what gets you from corner to the next corner. If you're having to shift more between those corners because you have a special cadence that you need to be able to ride, then you are not effectively putting the power to the cranks and thus your rear wheel. You're effectively gliding and not efficiently maintaining momentum and ultimately wasting energy.
    Attached Images Attached Images
    Last edited by Motivated; 08-09-2005 at 11:01 AM. Reason: add graph
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    Quote Originally Posted by Motivated
    F1 cars don't have particularly tight gearing. Remember, their race speeds range from 50 to 200mph and they have 7 gears. Watch their rev ranges and they typically go from about 10,000-12,000 rpm to 19,000 rpm, shift and drop down to 12,000 rpm. They often come out of corners down in the 10,000 - 12,000rpm range. That is similar gearing to my Honda Accord which drops from about 5,000 to 3,500 rpm on upshifts.
    Well F1 cars have extremely specialized gearing that is altered for each specific track. Most bikers aren't changing their gearing for each course so you need to be versatile. F1 cars require changes to the engine mapping to suit each track. They have their biggest (broadest) powerband at Monaco and Hungary which have lots of slow speed corners. Maximizing their torque combined with a good traction control system is what shoots them from corner to corner (the corners are all close together). Of course maximum downforce is required at these tracks as well. Also, there's not many times that an F1 car's engine speed will drop down that low on most tracks except when they are pitting.

    Oval racing in the US has cars with small powerbands because speed doesn't fluctuate much.


    Quote Originally Posted by Motivated
    You think small shifts up are bad, I look at it the opposite way - big shifts down are bad.
    yes, big shifts down are bad indeed... especially the ones where you have to shift from your middle ring to the granny because you only have 27t on your road cassette. That's what I call a big shift down not the minimally farther spaced gearing of an 11-32 MTB cassette.

    Anyways, like Cloxxki said, in the long run a road cassette won't make you a better rider.

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    my biggest problem with 12-27 is

    something you tangentially bring up. That is the gap between the rings. Look at the graph I posted and you will see that my low gear in each ring is very close to the low gear in the the standard 22/32/44 rings. That is good, but finding those rings was not easy and my 29t ring does not have shifting ramps which led to a chain problem in a race.

    So, the problem with 12-27 is that it is best to have 5-arm compact cranks (58/94BCD), which are really getting rare with the move to external bearings. With 64/104 BCD cranks a 21t ring can be used on the granny, but then you are screwed on the middle and big rings. I use RaceFace turbine cranks, but they don't make any compacts now, neither does Truvativ or FSA. 4-arm has won!

    One further note about your torque-dystrophy theory - note that (at least in SoCal) Expert singlespeeders race shorter distances (typically 1 lap less) than the geared Experts. That is likely because the extra hard climbing efforts reduce endurance. Of course there are 24hr SSers, but that's just insane.



    Quote Originally Posted by eurorider
    Well F1 cars have extremely specialized gearing that is altered for each specific track. Most bikers aren't changing their gearing for each course so you need to be versatile. F1 cars require changes to the engine mapping to suit each track. They have their biggest (broadest) powerband at Monaco and Hungary which have lots of slow speed corners. Maximizing their torque combined with a good traction control system is what shoots them from corner to corner (the corners are all close together). Of course maximum downforce is required at these tracks as well. Also, there's not many times that an F1 car's engine speed will drop down that low on most tracks except when they are pitting.

    Oval racing in the US has cars with small powerbands because speed doesn't fluctuate much.




    yes, big shifts down are bad indeed... especially the ones where you have to shift from your middle ring to the granny because you only have 27t on your road cassette. That's what I call a big shift down not the minimally farther spaced gearing of an 11-32 MTB cassette.

    Anyways, like Cloxxki said, in the long run a road cassette won't make you a better rider.
    M

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    Quote Originally Posted by Motivated
    So, the problem with 12-27 is that it is best to have 5-arm compact cranks (58/94BCD), which are really getting rare with the move to external bearings. With 64/104 BCD cranks a 21t ring can be used on the granny, but then you are screwed on the middle and big rings. I use RaceFace turbine cranks, but they don't make any compacts now, neither does Truvativ or FSA. 4-arm has won!
    I'm using 94/58 Tune cranks (22/32/42) with 12-27 but something like 20/30/40 would be better. But with an 11-32t cassette, I could ride almost exclusively in the 32t middle ring.

    Quote Originally Posted by Motivated
    One further note about your torque-dystrophy theory - note that (at least in SoCal) Expert singlespeeders race shorter distances (typically 1 lap less) than the geared Experts. That is likely because the extra hard climbing efforts reduce endurance. Of course there are 24hr SSers, but that's just insane.
    hey, I'm no proponent of ss ...gears are there to increase efficiency, I am just saying to be a successful MTBer, you need a bigger powerband than a roadie. I have ridden my road cassette enough and I have adapted to it and the extra shifting but it's not faster overall. My powerband is too small now and I'm too reliant on what gear I'm in.

  29. #29
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    Just curious, but what age bracket do you race if you don't mind my asking. I usually race Expert in SoCal in 35-39.

    Doing Amateur Cup next weekend?

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    same

    Expert 35-39. I had to think about that for a minute because I've always raced 30-34, but this year broke through to the old man group. I don't race much up at big bear preferring rim nordic instead.

    I should be easy to recognize - I'm 6'4" and ride a turquoise yeti asr-sl (last year I was on a red Blur).

    So how is your season? Mine started mediocre racing at Southridge, and hasn't improved much - too much time online and not enough riding.
    M

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    Can someone sumarize here the optimal conditions for 2x9 or 3x9 with road cassette?

    As I see what people are saying
    2x9 = great for people who have alot of short hills (that don't use their granny much now)
    3x9 with road = great for long smooth hills

    I myself ride in New England with lots of short up and downs so should I be leaning towards 2x9?

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    same

    Expert 35-39. I had to think about that for a minute because I've always raced 30-34, but this year broke through to the old man group. I don't race much up at big bear preferring rim nordic instead.

    I should be easy to recognize - I'm 6'4" and ride a turquoise yeti asr-sl (last year I was on a red Blur).

    So how is your season? Mine started mediocre racing at Southridge, and hasn't improved much - too much time online and not enough riding.
    M

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    I Just Switched to a 2x9 set-up with...

    a 29/42 combo up front and an 11-34 cassette. The decision was one of simplicity. I live on Long Island where we are decidedly un-mountainous. As I never found myself in the granny gear, I decided to shed and by moving my BB inward a couple of mm's found i have a more efficient chainline in virtually every possible gear combo i use. I ride 1x9 on my rigid rig and love it! If i were blessed with some of the stuff a lot of you guys ride, i would likely shed the biggie and go 2x9 the other way.
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    2x9 probably

    I think a 2x9 would serve you best. If you spend a lot of time shifting now, it will only get worse with a road cassette. Add to this that smaller spacing - IMHO - means a cassette more easily clogs with mud, and more shifting in bad conditions in all likelyhood means more chance of a shifting mishap.

    As far as my own riding goes: I used a road cassette for marathons for a while, but in technical terrain I was shifting way too often for my liking. Plus I absolutely hate having to walk, so I have a use for a 20x32 or 22x34t granny. I missed it w/ the road cassette.

    For XC racing, I think next season I will ride 44/32 with an 11-34t cogset, maybe 12-34t. Most races here are either on wide open, flat hardpack of mean, twisty singletrack w/ no flow whatsoever (i.e. every corner means braking & upshifting).

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    if you're looking for a smaller middle ring and have some cash to burn then boone rings could be a good choice. i'm currently ordering a 20 t and 30 t and going to a 12-27 cassette. rings combined are a buck 20 but i figure they'll last forever, so in the long run it's not a bad investment. i think the middle ring alone is like 85 or something....

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    you finally got the point!

    Quote Originally Posted by Mr. Scary
    NONE of the pro mountain bikers use this stupid gearing, are any of you stronger than them?
    that's exactly the point Scaryboy! it seems you still didn't get what its all about but that wasn't to be expected.

    none of the Pro riders in the road peloton uses compact chainrings/cranks and "bigger" cassettes...does that mean all other mortals have to ride with 39/53 and 11-21 cassette on a roadbike???? c'mon....don't you realize how stupid your argument is?

    i guess you are still suffering from the shock of Cannondale offering cheapo taiwan carbon frames

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    hey does anybody know if a 10spd DuraAce rear derailleur (RD-7800) works fine with a 11-32T cassette??

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    Quote Originally Posted by Motivated
    Expert 35-39. I had to think about that for a minute because I've always raced 30-34, but this year broke through to the old man group. I don't race much up at big bear preferring rim nordic instead.

    I should be easy to recognize - I'm 6'4" and ride a turquoise yeti asr-sl (last year I was on a red Blur).

    So how is your season? Mine started mediocre racing at Southridge, and hasn't improved much - too much time online and not enough riding.
    I'm gonna try to race Rim Nordic this weekend. I'll be looking for you.

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    I've gotta go with Nino and Duckman on this one. I use a 12-27, and I like the setup. Any muscle memory based on cadence is going to be dictated by the terrain, not the cassette. If you are riding long, steady grades, it doesn't matter what cassette you are using, your legs are going to get used to it. If you are riding terrain with varying grades, you are going to have to decide whether to switch gears or hammer it out regardless of what cassette you are using. The only difference is that with the 12-27, you must shift an extra cog or two when you do, no big deal. But the benefits outweigh the drawbacks IMO.
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    Scary, what do you ride now if you don't mind me asking...

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    pfffffffffff............

    Quote Originally Posted by Mr. Scary
    Riding in the peloton is ALOT different than riding solo or riding offroad, Nino. If you actually rode your bikes rather than weighing them you would know this. As Cloxxki said, 12-27 will not make you faster. It may be lighter, but if you are not going faster-what's the point? Losing five pounds of body weight (you can easily afford to do this-I've seen pictures) will do more than the 100 grams saved on the cassette. Since this is weight weenies, body weight should be applicable as well.

    I have no vested interest in Cannondale, in fact I do not even own a Cannondale bike anymore. So move on to something new, please.
    just more hot air as we say over here

  42. #42
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    12-27 is lighter and works just as good as the MTB cassettes. I don't buy this shifting way too often argument either. I prefer pedalling in an RPM sweet spot and prior to road cassettes didn't like big jumps on the MTB cassettes.

    The real weakness of the road cassette is in the too tall granny gear. I sometimes wish I could "rest" riding up steep hills in races, like take it at a slower pace to avoid going into red. To do this with a road cassette the only thing to do is basically drop your RPM down low. The energy you save from riding slower uphill is offset by having to pedal at an uncomfortably low RPM. I want to go back to a MTB cassette so I have this option, but otherwise I like roadie cassettes a lot.
    If in doubt - pedal harder!!!

  43. #43
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    Ohhhh, to whoever asked about road derailleur with MTB cassette:

    I remember Cloxxki posting that a road derailleur will work with an 11-32 and, depending on the hanger, also with an 11-34. That, and numerous other anecdotal evidence posted that Shimano claim about 27t being max for road derailleurs is not true.

    As I have thought about switching to a MTB cassette, I examined my Ultegra clad MTB to assess the feasibility of this and thought I could fit an 11-32 without problems and, if I increased the derailleur tension, possibly the 11-34 too.

    Maybe just try fitting a MTB cassette to a road bike to see if it works before committing?
    If in doubt - pedal harder!!!

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    Smile Is light weight everything?

    If lightest is your goal by all means choose dura ace 11 - 27. WIth that being said... I opted to change out my mt cassette for an urban adventure race(mostly road riding). It was about 5 hours long. While it was certainly lighter I found myslef shifting all the time from the second to the third chain ring. My partner who seems to buy heavy stuff on purpose didn't have this problem. I think that real mountain biking would call for even more shifting??
    11 - 27 lighter 2 x 9 more efficient end of debate??

  45. #45
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    Quote Originally Posted by gdunha
    11 - 27 lighter 2 x 9 more efficient end of debate??
    12-27 = lighter and more efficient....
    2x9 = slightly heavier and very tall granny, good for some people
    End of debate??
    Last edited by DaFireMedic; 08-20-2005 at 12:47 PM.
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    why do you care?
    Last edited by peabody; 08-20-2005 at 02:58 PM.

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    Quote Originally Posted by sean350
    Another question, it seems like most people's 2x9 setups keep the outer and middle ring. Wouldn't it make more sense from a weight standpoint to ditch the outer and keep the middle and inner chainring? I know you don't get the higher gear, but you could put a 40 tooth middle with a 24 tooth granny, along with an 11 tooth cassette, and get a similar top end to a 44 x 12. Let me know the deal, por favor!
    -Sean
    Sorry to barge in on this, but it seems that this discussion ended up into a holy war about using 42/29 (big+middle ring)x11-34 or 42/32/20x11-27 (MTB vs. road cassette) wereas sean350 was asking about using middle and granny and ditching the big ring.

    I myself am considering something like 36/24x11-34.

  48. #48
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    Quote Originally Posted by djska
    Sorry to barge in on this, but it seems that this discussion ended up into a holy war about using 42/29 (big+middle ring)x11-34 or 42/32/20x11-27 (MTB vs. road cassette) wereas sean350 was asking about using middle and granny and ditching the big ring.

    I myself am considering something like 36/24x11-34.

    I have that setup on my bike. 36/22 x 12-27 though. Works great, but thanks to the large jump between the rings plus the roadie cassette, in my particular case, it is inferior to a 3-ring setup for racing.
    If in doubt - pedal harder!!!

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    "very tall granny" ??????

    Very tall granny??? 29/34 = .885 vs 24/27 4% difference??? I beleive this qualifies as a myth?

    Would more shifting qualify as more efficient??

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    Quote Originally Posted by djska
    Sorry to barge in on this, but it seems that this discussion ended up into a holy war about using 42/29 (big+middle ring)x11-34 or 42/32/20x11-27 (MTB vs. road cassette) wereas sean350 was asking about using middle and granny and ditching the big ring.

    I myself am considering something like 36/24x11-34.
    I don't think that this discussion has turned into any kind of war. With the exception of the Mr Scary intervention, it has been pretty civil. In addition, I have heard some interesting viewpoints and ideas about these setups that I haven't heard before. The original question was about the advantages/weight savings of either a 2x9 setup or a 3x9 with a 12-27 cassette. Its pretty much stayed on topic.

    To answer gdunhas question, the extra shifting is not more efficient. This is the disadvantage to the 12-27 setup. The efficiency comes in the narrow gear ranges allowing you to more efficiently maintain cadence on climbs. This is particularly so on long climbs without a lot of up and down sections. These represent a large portion of MTB terrain and while your lungs will recover, your legs generally don't, which is why a good cadence is important. The narrow gear ranges help with this.

    This is really a question of preference and terrain. I live at the base of a 10,000' mountain and climbing is what I do the most. I don't shift as often as I might in other areas, and the 12-27 seems to work best for me here. It has the added benefit of being lighter. I use an XT derailleur and have an XT cassette that I can throw on at any time should I feel that it is better suited for the terrain.

    BTW: The 2x9 is a good setup, if you have power. I have a friend with standard 3x9 setup that essentially rides it as a 2x9. He never uses his granny gear and just motors up hills. He's a good expert class racer and he's got the power to do that.
    Last edited by DaFireMedic; 08-21-2005 at 01:46 PM. Reason: misspelling
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    Quote Originally Posted by nino
    2x9 needs powerful legs! jumps from one gear to the next are pretty big so you need the power to pedal and the usually missing granny ring doesn't help on steep climbs either. your idea with the different chainring setup is going in the right direction but overall such a setup is still heavier than

    3x9 with 12-27 cassette:
    cassette: Dura Ace 180g / Ultegra 230g......XTR 11-34= 242g.... go for the DA -60g !!
    shorter chain with 12-27cassette........................................ ...........................-20g
    Aluminium 20t granny and Al-bolts............................................. ...................+20g
    short cage Dura Ace derailleur 180g...old XTR 235g/ new XTR 200g/ X.O 198g..-20-55g

    overall savings with 3x9 (12-27) depending your parts choice is up to 115g

    by the way - there's triple rings out there that weigh less than your typical Shimano double ring setup: Extralite or TA Specialite have rings that weigh as little as 115g all together. rememeber a 44t XT weighs already 85g, a 32t is 45g.

    the 12-27 cassette has the gears spaced much closer. this is like having "semi-gears" compared to a usual MTB cassette. it allows you to keep your cadence which is a big plus on climbs. you end up beeing faster as you can adjust the gears according to your power. a MTB cassettes big gaps often lets you remain in a lower gear as the next one would already be too much effort....the closer spaced cassette allows you to do one more shift and this makes you faster, it requires MORE shifting compared to a MTB cassette. this needs some getting used to at first but as i said the constant cadence and faster speeds will convince you and you really get accustomed in no time.

    by having a 20t granny in the front you regain the lost low gear. 20/27 equals 22/30 which should be low enough.

    definitely go with the DA cassette and derailleur! there's too much savings there! and the shorter derailleur makes for precise shifts and is also less likely to be damaged or bent because of it's compact size.
    Better yet go to a single speed for greater weight savings and you should be that much faster. Personally a prefer my 34x20 on my 29er. If not that try one and if you don't like it try the other. Cheers

  52. #52
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    Quote Originally Posted by nino
    just more hot air as we say over here
    Over where, in Switzerland? So you Swiss routinely dismiss sound arguments, must be some kinda country...
    It's way more shifting for anything off-road, as it offers road ratios. I would love to see your terrain becuase the climbs must be smooth and rise at a pretty consistent 6-9% grade to make this gearing useful.
    You have great knowledge of lightweight parts, but this is not competent off-road gearing no matter how you slice it.

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    I am actually thinking of doing something along the lines of a 38-22 x 11-32 (or maybe the 12-27). I almost never use my 44. I'm in SoCal, and my rides tend to have really huge ascents, followed by technical descents, so I almost never have the occasion to shift into my big ring. I don't even know that if I raced I'd shift into the big ring. Anyhow... this has been an interesting discussion. I typically hang at the singlespeed and 29er boards, and they are way more civil than this one. The "save weight" board is kind of like the "Jerry Springer Show" of mtbr.com. Very entertaining stuff, indeed. Thanks for the input!
    -Sean

  54. #54
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    Quote Originally Posted by peabody
    Over where, in Switzerland? So you Swiss routinely dismiss sound arguments, must be some kinda country...
    It's way more shifting for anything off-road, as it offers road ratios. I would love to see your terrain becuase the climbs must be smooth and rise at a pretty consistent 6-9% grade to make this gearing useful.
    You have great knowledge of lightweight parts, but this is not competent off-road gearing no matter how you slice it.
    i'm in zurich.
    switzerland is pretty hilly and uphills are usually more than just around the next bush...
    if you ride long uphills there's no better than close gearing. in constant up and down it's no good. just read what i wrote above.
    if it's faster it is competent in my eyes, no matter how you slice it.
    cheers

  55. #55
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    doubt it. cage is probably too short to handle the chain length u need with a mtn cassette. it'll work but you won't have as many gears as u might like

  56. #56
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    Quote Originally Posted by peabody
    the climbs must be smooth and rise at a pretty consistent 6-9% grade to make this gearing useful.
    Ninos argument is valid with any sustained grade, it doesn't matter how steep or level. It doesn't have to be smooth either, just not a constant up and down, but even then its manageable, just less efficient. People are picturing a constant switching between chainrings, and that is just not the case. The vast majority of the shifting is still on the cassette, and it takes a drastic change in grade to switch chainrings, just as with a mountain cassette.
    If you want to play with electricity, more power to ya......

  57. #57
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    I typically hang at the singlespeed and 29er boards, and they are way more civil than this one. The "save weight" board is kind of like the "Jerry Springer Show" of mtbr.com. Very entertaining stuff, indeed. Thanks for the input!
    You've obviously never been to the Socio/Political/Economic forum (aka Forum 88). we call it the asylum.

  58. #58
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    Quote Originally Posted by Boj
    I have that setup on my bike. 36/22 x 12-27 though. Works great, but thanks to the large jump between the rings plus the roadie cassette, in my particular case, it is inferior to a 3-ring setup for racing.
    Going from 36 to 22 is too big a jump I think (14T). It is probably best to stay within 10 to 12T like it normally is.

    If you use such a two ring setup with an 12-27 you have a very limited total range, not reall y good for climbing but also limited for road use. I think that to have benefit of a two ring setup you need a big range cassette.

  59. #59
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    Well I tried a 27-12 cassette with a 44/32/20 combo. I loved the close ratios at anything over 15-20km. Undulating double track, fireroad, road this cassette really excelled.

    I had a really problem with it in single track though. I am used to staying in middle ring with a 34-12 and having a fairly low gear available to mash up short steep hills. The 27/32 combo was just too big for me. The 20t front chainring exagerated the pedal feedback on my new blur xc, and the rear cassette forced me to use granny abit more than I liked. I had too put up with feeling alot more pedal feedback and hear the chain rub against the rear stay (the blur does not have good clearance for use of a 20t front chainring).

    The biggest problem for me is that it has the same spaced gearing in the lowest three gears on the cassette (27-24-21) as my 34-12. This is where I do most of my climbing up steep fireroads to the single track on races. The ratios are not any closer together where I need it for climbing....but closer for moderate speed flowy stuff.

    I am a midpack sport rider and don't produce much power, perhaps the 27-12 is not for me. I could see a flatter course with lots of fast double track working well with this cassette, however we don't have courses like that here lately.

    A smaller middle chainring would probably make me like this cassette alot more, so far it has been a failled experiment for me.

    Thanks for the ideas though guys!

  60. #60
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    source for 30t ring

    http://www.salsacycles.com/comps_chainrings.html

    I bought one for $30 from Adrenaline Bikes. It works very well, weighs 34g. You might also want to use a 42t big ring. If you ditch the 12-27 you may want a 30t with your 12-34 or 11-32 (better) to keep you in the middle ring.

    How do you like the Blur? I don't remember you saying you were doing this on a VPP bike. My Blur (original flavor) also has very minimal room around the granny - I had to shave the heads off the chainring bolts when I went to a 24t aluminum ring because they hit the cap on the pivot (heck, I thought there wasn't enough room for a 22t granny!). My 20/30/42 x 12-27 setup is on a non VPP bike with lots of room down there.



    Quote Originally Posted by GspotRider
    Well I tried a 27-12 cassette with a 44/32/20 combo. I loved the close ratios at anything over 15-20km. Undulating double track, fireroad, road this cassette really excelled.

    I had a really problem with it in single track though. I am used to staying in middle ring with a 34-12 and having a fairly low gear available to mash up short steep hills. The 27/32 combo was just too big for me. The 20t front chainring exagerated the pedal feedback on my new blur xc, and the rear cassette forced me to use granny abit more than I liked. I had too put up with feeling alot more pedal feedback and hear the chain rub against the rear stay (the blur does not have good clearance for use of a 20t front chainring).

    The biggest problem for me is that it has the same spaced gearing in the lowest three gears on the cassette (27-24-21) as my 34-12. This is where I do most of my climbing up steep fireroads to the single track on races. The ratios are not any closer together where I need it for climbing....but closer for moderate speed flowy stuff.

    I am a midpack sport rider and don't produce much power, perhaps the 27-12 is not for me. I could see a flatter course with lots of fast double track working well with this cassette, however we don't have courses like that here lately.

    A smaller middle chainring would probably make me like this cassette alot more, so far it has been a failled experiment for me.

    Thanks for the ideas though guys!
    M

  61. #61
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    Thanks for the 30t middle ring suggestion. I think it is worthy mod for me. However I have m960 xtr cranks that allow a 31t....but I'm not sure if it allows for any smaller. Of course I am always hoping that training will yeild an engine that has more power...so I don't have to worry about the granny ring...but I am not so gifted a person.

    I usually use at 22t granny ring. The 20t granny on the blur xc exagerates the pedal feedback even more. It becomes abit distracting with the 20t. With the 20t and the 27-12, I start to get quite abit of chain rub on the lower rear triangle weld around the lower rear pivot, with anything higher than the 4th lowest gear on the cluster. Because of the chain rub it does not make using the full range of the granny gear very conducive to use; as I am sure that it will damage the frame after awhile.

    The blur xc has been good. Fairly plush and fairly efficient. I can set it up abit soft for fun rides and firmer for races. I like that option. My epic was trustworthy and easy to ride. But never felt smooth even though it softened the bumps enough to make even the longest epic bearable. So far I like how it rides when I set it up abit softer than factory suggestions, but I do get more suspension movement. What sag or sweet spot did you figure out for racing verses casual riding?

    Back on track here, I'm going to keep playing with the 27-12 on my hardtail and see how it works out, since I won't have the 20t problems with suspension interaction and linkages rub. Thanks for the input.

    Quote Originally Posted by Motivated
    http://www.salsacycles.com/comps_chainrings.html

    I bought one for $30 from Adrenaline Bikes. It works very well, weighs 34g. You might also want to use a 42t big ring. If you ditch the 12-27 you may want a 30t with your 12-34 or 11-32 (better) to keep you in the middle ring.

    How do you like the Blur? I don't remember you saying you were doing this on a VPP bike. My Blur (original flavor) also has very minimal room around the granny - I had to shave the heads off the chainring bolts when I went to a 24t aluminum ring because they hit the cap on the pivot (heck, I thought there wasn't enough room for a 22t granny!). My 20/30/42 x 12-27 setup is on a non VPP bike with lots of room down there.

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