# Switch to 11-34 cassette



## ochness (May 28, 2010)

I am wanting to switch to an 11-34 cassette to make it easier to climb with my compact double chain ring. I know I'm going to need to switch out the rear derailleur for a mountain bike type rear derailleur so I can use all of the gears on the 11-34 cassette. I'm just not sure what type of mountain bike rear derailleur I need to get to make this work. I am currently running a 10 speed rear cassette and I know there is a way to make this work I just don't know what I need to get to make it work. I have an Ultegra rear derailleur on right now so I would like to get the same quality.

Thanks for any suggestions on this.

p.s. I know I will need to get a new chain as well.


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## RussellS (Feb 1, 2010)

Any Shimano rear derailleur will work. As long as it is a normal rear derailleur that has the spring pull the cage down to the small cog. Shimano made some mountain bike rear derailleurs with the spring reversed so it pulled the chain up to the biggest cogs. Check to get one the same as a road rear derailleur. Assume you are running 9 speed since I don't think there are 10 speed 11-34 cassettes yet. Any 9 or 10 speed rear derailleur will work the same.


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## tom_h (May 6, 2008)

I'd be cautious of saying "Any Shimano rear derailleur will work"

Shimano Rear Der are often available with "short", "medium", and "long" cages, depending on how much chain wrap is required.

The required chain wrap in OP's configuration is (50-34) + (34-11) = 39 teeth. Shimano is usually a bit conservative, but there's no way a std "short" cage will work, those have a wrap capacity spec of around 27-28 (IIRC).


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## baker921 (Jul 20, 2007)

I don't think you can use Shimano 10 speed MTB cassettes. There is an issue with the spacing. You can use 9 speed though. If you want to stay with 10 speed I would suggest you use Sram http://www.sram.com/sram/road/products/sram-pg-1050-cassette or http://www.sram.com/sram/road/products/sram-pg-1070-cassette but you will be limited to 11-32. XT is generally considered to be equivalent to Ultegra but its a bit like comparing apples with oranges. Road and MTB components are designed with differing priorities.


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## ochness (May 28, 2010)

That is why I'm confused on what to use. Any specific suggestions on models would be great. I'm hoping a medium cage mountain bike rear DER will work.


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## baker921 (Jul 20, 2007)

Shimano XT RD have a wrap capacity of 33 short cage and 45 long and yes they are often conservative. Here is a link to Shimano site http://bike.shimano.com/publish/content/global_cycle/en/us/index/products/mountain/deore_xt.html#


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## ochness (May 28, 2010)

So what is the main difference between the Deore XT and the XTR products?


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## baker921 (Jul 20, 2007)

ochness said:


> So what is the main difference between the Deore XT and the XTR products?


Weight price bling. XTR = Dura-Ace.


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## charlox5 (Jan 31, 2011)

if you're considering SRAM i'm using the sram 1050 11-32 with a rival mid cage rear derailleur. it works very well.


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## cxwrench (Nov 9, 2004)

RussellS said:


> Any Shimano rear derailleur will work. As long as it is a normal rear derailleur that has the spring pull the cage down to the small cog. Shimano made some mountain bike rear derailleurs with the spring reversed so it pulled the chain up to the biggest cogs. Check to get one the same as a road rear derailleur. Assume you are running 9 speed since I don't think there are 10 speed 11-34 cassettes yet. Any 9 or 10 speed rear derailleur will work the same.


hold on a minute...
this is NOT true...you can NOT use any shimano rear derailleur and have it work. if the OP is running a 10 spd road set-up...he can run ANY 9 speed shimano mtb rear derailleur and it will work great. you can NOT use the new dyna-sys derailleurs. the geometry of the new 10spd derailleurs is different than what the shifter needs. trust me, we've done a bunch of these on road bikes recently. you can use the 10spd 11-34 cassette, but you need to use an older, 9 speed derailleur. 
as to why you don't think a low-normal derailleur will work...??? it should work the same as a normal (high-normal) derailleur. haven't tried it, but i can't think of any reason it wouldn't work.


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## ericm979 (Jun 26, 2005)

The low normai will work, it'll just shift backwards. The right brake lever will shift the rear derailleur to a smaller cog and the small lever will shift it to a larger cog.


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## ochness (May 28, 2010)

Thank you cxwrench. I will look for a 9 speed mountain bike rear der. I'm looking at the Deore XT RD-M772-SGS, do you think this one would work for what I'm looking to do?

Thanks again for your help.


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## cxwrench (Nov 9, 2004)

yep, that should work just fine:thumbsup:


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## ochness (May 28, 2010)

Thanks again for the help...one last question (ok I'll probably have more) what size chain do you think I will need to get?


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## m_s (Nov 20, 2007)

cxwrench is right, everyone else who posted about compatibility is wrong.


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## MerlinAma (Oct 11, 2005)

I've got a 10 speed 11-34 IRD cassette but haven't tried it yet. Leonard Zinn actually said the 9 speed MTB derailleur would work. Need to get one.


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## KenS (Jan 28, 2004)

ochness said:


> Thank you cxwrench. I will look for a 9 speed mountain bike rear der. I'm looking at the Deore XT RD-M772-SGS, do you think this one would work for what I'm looking to do?
> 
> Thanks again for your help.


The M772 is a new design and the reviews on mtbr.com have been mixed. I chose the older design, M771, for a build I am working on.


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## baker921 (Jul 20, 2007)

cxwrench said:


> ...... the new dyna-sys derailleurs. the geometry of the new 10spd derailleurs is different than what the shifter needs. trust me, we've done a bunch of these on road bikes recently. you can use the 10spd 11-34 cassette, but you need to use an older, 9 speed derailleur.


So does it follow that the Dyna-sys derailleurs will only work with Dyna-sys 10 speed shifters? and presumably you could run an 11-36 cassette?


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## velojon (Mar 8, 2006)

*11-34 Cassette*

There has been a long chain of questions and discussion of this topic in Lennard Zinn's column in VeloNews recently which is pretty comprehensive if you chase down all the pieces:

http://velonews.competitor.com/2011...-compatibility-and-new-years-feedback_155209#


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## spade2you (May 12, 2009)

Out of curiosity, why are you needing a 11-34? I'm not bashing the configuration, but if you have a 34, why do you need a 11 (and vice versa)? Don't get me wrong, I like compacts and high cadence, but it's rare that I'm too overgeared unless it's really steep.


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## MerlinAma (Oct 11, 2005)

spade2you said:


> Out of curiosity, why are you needing a 11-34? I'm not bashing the configuration, but if you have a 34, why do you need a 11 (and vice versa)? Don't get me wrong, I like compacts and high cadence, but it's rare that I'm too overgeared unless it's really steep.


I'll give you my reason. In Colorado I seem to be at one end or the other. Last year I had a 34-28 low gear. After riding up Mt. Evans one day and then riding from Golden to Estes Park, my legs were toast. I'm sure I would have gone no faster but have lower gears may have kept my legs from getting trashed at low rpms. After a day off at Estes Park, we went to Granby via Trail Ridge Rd, and on the last day had a century ride to Edwards. I could not stand (on the bike) for the first part of the last day. Eventually I warmed up enough so I could but it was not easy. 
On the other hand, there were several occasions where the 50-11 let me pedal with some resistance at high rpm. Did I "need" it. Probably not. But if I wasn't in the 50-11, I was more than likely back in my 34-28.  
Those middle gears were really more spacers than anything else!


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## ochness (May 28, 2010)

I'm looking at making a change to try and be able to ride hills better without having to change out my compact double for a triple...and be able to gain the advantage of a triple. I live in an area that is surrounded by hills that are pretty steep and long. I'm a big guy and I struggle on hills and in no way can I keep up with my friends who are all smaller riders. I have read that bigger riders need to be able to try and keep a higher cadence when riding hills and with my current setup I cannot keep a high enough cadence. 

I know there are going to be people say, ride more hills, lose weight and all of that stuff, but I'm just trying to make my riding more successful and more enjoyable. It's embarrassing to get dropped every ride and have your friends have to wait for you at the top of the hill...or even worse ride back down to see how I'm doing on the way up. 

I don't know...maybe I'm completely wrong in my thinking.


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## spade2you (May 12, 2009)

The bigger low gears will allow you to climb with higher cadence, but I don't think you should expect the gearing to allow you to keep up. Climbers will be spinning at a high cadence AND in a higher gear. You'll be able to climb more comfortably at your desired pace and maybe have a gear to spare, but that's about it. 

Weight loss AND increased power will make you a faster climber, more specificially your power to weight ratio. Truth be told, being a light rider on a light bike makes climbing a lot easier than one might expect.


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## ochness (May 28, 2010)

Ok, maybe I'm wrong in thinking that I will "keep up" with my friends but I want to more comfortable and not feel like I have just expended most of my energy half way through my ride on some damn hill. AT 6' 3" and 270 I'd love to drop a bunch of weight and be a more successful rider, but that hasn't happened as fast as I would want and something that I'm working on.


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## spade2you (May 12, 2009)

ochness said:


> Ok, maybe I'm wrong in thinking that I will "keep up" with my friends but I want to more comfortable and not feel like I have just expended most of my energy half way through my ride on some damn hill. AT 6' 3" and 270 I'd love to drop a bunch of weight and be a more successful rider, but that hasn't happened as fast as I would want and something that I'm working on.


You'll be substantially more comfortable. 

As for weight loss and fitness in general, the best results often come from the plan that builds a solid foundation, not something based on quick results.


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## wedge962005 (Jan 4, 2010)

I did the 53-39 with an 11-36 last year to help me get up more monster climbs as I built strength, fitness and lost weight. The big positive for me was the decreased impact on my knees. I was able to finish rides with friends involving a great deal more climbing and still be able to ride and walk the next day. Now I'm just going 11-28 in the back as a result of the strength I built up while riding the Frankenbike.

I was using Ultegra shifters, 10-speed XT 11-36 and a 9-speed XT rear derailleur. It worked but it isn't the smoothest thing in the world. You end up needing to coax the shifting and it requires frequent cable adjustments but it works when you need it. If you end up needing this, or plan on needing this, as a permanent solution given the area you ride in the investment in switching to SRAM could pay off. With SRAM you could use their 10-speed mountain bike derailleur and have perfect shifting. This has to do with the cable pull and release amounts being the same between SRAM road and mountain where Shimano has different lengths.

Cassette type does not matter, Shimano and SRAM 10-speed are the same.

Good luck with this setup, I hope it helps you stay with your friends and avoid knee damage like it did for me.


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