# Shimano 105 RD-5701-GS 10-speed medium cage derailleur will take a 36t cassette



## aclinjury (Sep 12, 2011)

I'm happy to release an unoffical report that a Shimano 105 RD-5701-GS medium cage rear deraileur can accept a 36t cassette on at least 3 bikes so far (Serrotta Meivici, Colnago CLX, Trek Madone). Officially, this derailleur is spec'd at 32t cog max, but 36t has been found out to work fine on the 3 bike frames mentioned above.

Of the 3 above frame, the Serotta and the Colnago have longer derailleur hangers, and the Madone has a shorter hanger. So, the Serotta and Colnago take a 36t easily with room left to spare, while the Trek with its shorter hanger will need the b-tension screw turned in most of the way, but it will work flawlessly.

This RD-5701-GS derailleur has been tried with DA 7900 and Ultegra 6700 shifters, but I suspect that older DA 7800 and Ultegra 6600 shifters will also work fine too since all these Shimano road 10speed shifters have the same pull ratio?

Anyway, I thought I would report this for those of you who have tandem or gravel or adventure bikes with these shifters and contemplate if a 36t cassette would fit, it most likely will.

Note: Shimano also makes different varient of this derailleur, the RD-5700-GS. Officially, this one is spec'd at only 30T max. The one I tried was RD-5701-GS, spec'd at 32T max. So pay attention to the model number when you buy.


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## Lombard (May 8, 2014)

aclinjury said:


> I'm happy to release an unoffical report that a Shimano 105 RD-5701-GS medium cage rear deraileur can accept a 36t cassette on at least 3 bikes so far (Serrotta Meivici, Colnago CLX, Trek Madone). Officially, this derailleur is spec'd at 32t cog max, but 36t has been found out to work fine on the 3 bike frames mentioned above.
> 
> Of the 3 above frame, the Serotta and the Colnago have longer derailleur hangers, and the Madone has a shorter hanger. So, the Serotta and Colnago take a 36t easily with room left to spare, while the Trek with its shorter hanger will need the b-tension screw turned in most of the way, but it will work flawlessly.
> 
> ...




This is certainly interesting. Where did you read this unofficial report? I believe you indeed could make this work, but it would not be optimal. It seems like quite a stretch for a road RD. The first sign that your largest cog is too big for your RD is that you will hear a "motor boating" or "purring" sound when you are in that largest cog. That sound is the jockey pulley hitting the cog teeth. You could certainly find a longer b-tension screw to try and quiet this down a bit.

And yes, shift pull ratios are the same for 5600/6600/7800 as they are for 5700/6700/7900. The 5800/6800/9000 however, are different.


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## loxx0050 (Jul 26, 2013)

Lombard said:


> This is certainly interesting. Where did you read this unofficial report? I believe you indeed could make this work, but it would not be optimal. It seems like quite a stretch for a road RD. The first sign that your largest cog is too big for your RD is that you will hear a "motor boating" or "purring" sound when you are in that largest cog. That sound is the jockey pulley hitting the cog teeth. You could certainly find a longer b-tension screw to try and quiet this down a bit.
> 
> And yes, shift pull ratios are the same for 5600/6600/7800 as they are for 5700/6700/7900. The 5800/6800/9000 however, are different.


I think you're reading it wrong. The OP didn't read an unofficial report but is making an unofficial report. At least that is the way I read the post. I could be wrong, it is Friday and my concentration is slipping as it gets closer to the end of the day.


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## tednugent (Apr 26, 2010)

the "unofficial" report is aclinjury's experience of using the derailleur on 3 different bicycles.



Lombard said:


> This is certainly interesting. Where did you read this unofficial report? I believe you indeed could make this work, but it would not be optimal. It seems like quite a stretch for a road RD. The first sign that your largest cog is too big for your RD is that you will hear a "motor boating" or "purring" sound when you are in that largest cog. That sound is the jockey pulley hitting the cog teeth. You could certainly find a longer b-tension screw to try and quiet this down a bit.
> 
> And yes, shift pull ratios are the same for 5600/6600/7800 as they are for 5700/6700/7900. The 5800/6800/9000 however, are different.


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## Lombard (May 8, 2014)

loxx0050 said:


> I think you're reading it wrong. The OP didn't read an unofficial report but is making an unofficial report. At least that is the way I read the post. I could be wrong, it is Friday and my concentration is slipping as it gets closer to the end of the day.




Yeah, yeah, I know. It's Friday and I want to RIDE!!!!


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## cxwrench (Nov 9, 2004)

Good info acl! :thumbsup:


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## aclinjury (Sep 12, 2011)

yes, the unofficial report is from my experience of hands-on trying the RD-5701GS on these frames.

We test roded all 3 bikes by climbing some short hills moving up and down the whole cassette range in combination with the big and small chainrings. All shifting along the cassette is flawless. Yes with a wide range cassette shifting is not as fast as with an 11-23 or 12-25, but, it is smooth and exhibit no hiccups.

And to make it clear, the upper pulley did clear the largest 36t cog on all 3 bikes. There is absolutely no grinding.

for the Trek Madone, the factory b-tension screw was used. There was no need for any special extra long b-tension screw, nor was there a need to use the trick of installing a smaller 10t (verses 11t) upper pulley wheel.

All 3 bikes had compact 34/50 crank. I assume that if anyone is looking to use a 36t cassette, he at least has the sense to use it with a compact crank!

So, for the folks thinking of buying a Shimano XT 9speed mtb derailleur, you now have another strong candidate in the RD-5701-GS if your intention is to go to 36t cassette max. 

Now if you're thinking possibly 40t cassette, then I'm afraid you will definitely need to consider either the Shimano XT M772 or XTR M972 long cage ones.


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## Lombard (May 8, 2014)

OK, Aclinjury. Your first hand experience is good enough! And you got the CX seal of approval.

I'm a believer now! :thumbsup:


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## aclinjury (Sep 12, 2011)

Lombard said:


> OK, Aclinjury. Your first hand experience is good enough! And you got the CX seal of approval.
> 
> I'm a believer now! :thumbsup:


I shall revel a bit in CX's stamp of approval. This sort of thing just doesn't happen much!


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