Lightest 10 speed shimano rear mech to take 32T?

Discuss light weight issues concerning road bikes & parts.
Paul8v
Posts: 12
Joined: Sun Jan 12, 2014 4:55 pm

by Paul8v

Hi,

I'm new to the board (First post) Starting to look at reducing the weight of my bike a bit, I've already changed wheels, cassette, tyres, saddle etc. (Not sure if I can post links up until I have a few more posts)

I've been inspired by some of the rear mechs on here that have received some dremmel action and I fancied giving it a go myself.

I'm running an 11-32t ultegra rear cassette (I know a closer ratio would be lighter but I plan to do Ventoux and I'm no Pantani!) I currently have a 105 rear mech which can cope with the 32t. I plan to have a muck about with this but if there is a mech out there which will cope with the 32T that is lighter to start with then it will be easier. I plan to lose some weight from the front plate and some other areas where I can get a way with it and they run a fibre lute cage and some carbon jockey wheels. If there is no other mech that will do it I will have to try for a very light 105, has anyone done that yet?

Cheers

Paul

KLabs
Posts: 380
Joined: Wed Dec 01, 2010 4:29 am

by KLabs

Hi Paul8v, the Shimano M972 XTR SGS RD (or even GS?) RD should work just fine with 10spd STI levers...

thanks KL :)

Paul8v
Posts: 12
Joined: Sun Jan 12, 2014 4:55 pm

by Paul8v

Thanks KL, looks like it's about 40g lighter than the one I have, is there much that can be done to tune them? Looks like they have a carbon cage already which is good.

Paul8v
Posts: 12
Joined: Sun Jan 12, 2014 4:55 pm

by Paul8v

Other alternative I was thinking, could I fit a longer cage to a Dura ace? Would that achieve a higher rating for the cassette teeth number or are there other factors I haven't considered?

boots2000
Posts: 1438
Joined: Mon Oct 15, 2007 9:28 pm

by boots2000

I have a buddy with a 10 speed DI2 setup with a long cage derailleur. (Made by K-edge).
I have talked to them. They can do a mechanical Dura-ace with a longer cage too.
I was considering a 9000 derailleur with a long cage.

HillRPete
Posts: 2292
Joined: Tue Apr 12, 2011 8:08 am
Location: Pedal Square

by HillRPete

A Dura Ace mech can be made to handle 32T usually. You need to give it lots of "B screw". And fit it with a longer cage, or run a slightly short chain.

But really, going for minimal weight, and having a bike to tear around the mountains are two different chapters in my book.

Good luck.

Paul8v
Posts: 12
Joined: Sun Jan 12, 2014 4:55 pm

by Paul8v

I just fancied it from the point of view that it might be a bit of fun mucking around with the dremmel to make something a bit special (Same as with my car, I'm always tinkering with something on it!) I wouldn't want to remove as much as on that red anodised dura ace one just in case I took off too much and it lunched itself but I think some lightening may be possible.

Paul8v
Posts: 12
Joined: Sun Jan 12, 2014 4:55 pm

by Paul8v

The bike is ridden pretty hard over some badly kept roads so a super light build is out of the question!

Oswald
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Joined: Thu Jan 08, 2004 10:11 pm

by Oswald

How much do you weigh?

Paul8v
Posts: 12
Joined: Sun Jan 12, 2014 4:55 pm

by Paul8v

80kgs, I used to do a fair bit of weight lifting, I was 90kg but I've started lifting higher reps of less weight to tone up.

I wouldn't want to go much lighter as I will start to look too thin, I'm not in to the no upper body look!

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ultimobici
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by ultimobici

Paul8v wrote:Other alternative I was thinking, could I fit a longer cage to a Dura ace? Would that achieve a higher rating for the cassette teeth number or are there other factors I haven't considered?

Fitting a longer cage doesn't allow for a larger cassette sprocket, just a larger difference on the front, such as a triple. The deciding factor is the distance allowed between the top jockey wheel and the largest sprocket. The newer RD67 & RD57 mechs have capacity to handle a maximum 30T sprocket, but a 32T may not be ideal unless the hanger on your frame is a little longer or allows the B screw to move the mech enough.

Paul8v
Posts: 12
Joined: Sun Jan 12, 2014 4:55 pm

by Paul8v

ultimobici wrote:
Paul8v wrote:Other alternative I was thinking, could I fit a longer cage to a Dura ace? Would that achieve a higher rating for the cassette teeth number or are there other factors I haven't considered?

Fitting a longer cage doesn't allow for a larger cassette sprocket, just a larger difference on the front, such as a triple. The deciding factor is the distance allowed between the top jockey wheel and the largest sprocket. The newer RD67 & RD57 mechs have capacity to handle a maximum 30T sprocket, but a 32T may not be ideal unless the hanger on your frame is a little longer or allows the B screw to move the mech enough.

Thanks, I figured it might not be as easy as the longer cage, I'm sure I read about people fitting a smaller top jockey wheel to overcome this but I'm not such a fan of that as if anything I would rather fit a larger jockey wheels to help lower friction.

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Rick
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Joined: Sat Aug 29, 2009 4:30 pm

by Rick

KLabs wrote:Hi Paul8v, the Shimano M972 XTR SGS RD (or even GS?) RD should work just fine with 10spd STI levers...

thanks KL :)

That is what I am running (the SGS) with 7800 shifters and a 32 rear, 50/34 front, and the shifting is fantastically good. Truly great.
But I have no idea if it is the lightest.

wickedwheels
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Joined: Sat Jan 06, 2007 10:41 am
Location: NY

by wickedwheels

Why not put the new Ultegra 6800 one on a diet... assuming your shifters will work.

Paul8v
Posts: 12
Joined: Sun Jan 12, 2014 4:55 pm

by Paul8v

wickedwheels wrote:Why not put the new Ultegra 6800 one on a diet... assuming your shifters will work.

Yeah, I'm not sure if it would work as it is an 11 speed on the 6800.

With regards to taking it to bits, how do you remove the pivot pins? They look like a bit of a pig to get out.
Last edited by Paul8v on Sun Jan 12, 2014 9:52 pm, edited 1 time in total.

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