105 rear mech and 11-36 cassette?

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This topic has 28 replies, 17 voices, and was last updated 10 years ago by bluearsedfly.

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105 rear mech and 11-36 cassette?
bluearsedfly
Free Member

I’ve been thinking of lowering the gear ratios on my cx bike as I’m using it for everything at the moment and find the gearing a bit high for me on the longer rides/climbs.

Was thinking of bunging an 11-32 cassette on in place of the 11-25 but I’ve just remembered I have a nearly new 11-36 spare.

Apart from a longer chain, will the 36 work with the 105 mech or will it have to be something smaller?

Posted 10 years ago

Jamie
Free Member

Assuming it’s a medium cage 105 mech, and you’re running a double, then I think they top out at 32T.

Posted 10 years ago

jam-bo
Full Member

unlikely, mine struggled with a 32.

you can run 9 speed mtb mechs on 10 spd road shifters so a long cage XT would probably do it.

Posted 10 years ago

dirtyrider
Free Member

i had a 7090 Di2 working with a 11-36 XX Cassette a few years ago, assuming you are 1x at the front it should be ok,

requires 10t upper jockey wheel and a longer b-tension screw

Posted 10 years ago

reggiegasket
Free Member

the latest short cage 105 mechs are rated to 30t and the long cage to 32t, so you might be able make it work with the long cage with some tweaking of the tension screw.

Older 105 mechs are 27 or 28t rated though.

Hate to say it but 11-32 is surely enough for a crosser (unless you are on 1×10…)

Posted 10 years ago

scotroutes
Full Member

Jam bo has it. You want a long cage XT 9 speed mech. Lots of “cx” bikes are gonna end like this as folk are using them as tourers.

Posted 10 years ago

mickle141
Free Member

You’ll need to run a 9 speed MTB mech if you want to use a 36t cassette. Make sure it’s not a shadow one. a 9 speed Shimano MTB mech will work with either 9 or 10 Shimano speed road shifters.

Just had this very thing done to my cx bike at my local bike shop http://www.3peakscycles.com/%5B/url%5D (we have some big hills round here!)

Posted 10 years ago

njee20
Free Member

Why not a Shadow one? Other than the cable run potentially not being ideal, there’s no reason not to use a Shadow rear mech on a cross bike, as long as it’s a 9 speed one.

Posted 10 years ago

thisisnotaspoon
Free Member

Jam bo has it. You want a long cage XT 9 speed mech. Lots of “cx” bikes are gonna end like this as folk are using them as tourers.

This +1

Although depending on the front ratios, a ‘short’ XT mech might work as they’re really a medium.

Posted 10 years ago

bluearsedfly
Free Member

It’s 46/36 upfont, presume it’s a longer mech? (can only see short/med on CRC).

@reggiegasket only looking at the 11-36 as I have one spare, have no problem putting a 32 on instead.

Looks like it’s a case of suck it and see? If not I will try a 32 then look at a longer XT mech.

So the 9 speed XT stuff is a direct fit/no mauling with pull ratios etc?

Thanks lads.

Posted 10 years ago

scotroutes
Full Member

46-36=10
36-11=25
10+25=35

Max capacity of a “medium” mech is 33T. A “long” will do 45T

http://www.chainreactioncycles.com/shimano-xt-m771-9-speed-rear-mech/rp-prod20698

No mucking about with pull ratios or anything. It’ll fit straight on.

Posted 10 years ago

crazy-legs
Full Member

Just ordered an 11-36 XT cassette for my CX too (for the Three Peaks). Hoping it’ll work with the medium cage XTR rear mech. In theory that’s max rated at 34T, in practice I’ve managed to bodge them before so here’s hoping.

Your 105 probably won’t work though, too short. Should be able to stretch it to 30 or 32.

Compatibility with MTB and road stuff now can be a total pain.

Posted 10 years ago

bluearsedfly
Free Member

Does it have to be 9 speed or can it be 10? Would be nice to bung a clutch mech on to stop the slap. The 105 mech seems pretty weak.

Presume the M772 mech is the 9 speed mech to go for?

Posted 10 years ago

scotroutes
Full Member

Has to be 9 speed

Posted 10 years ago

bluearsedfly
Free Member

Bugger, not long since sold an immaculate XT 9 speed rear mech on here. Sods law.

XT GS cage as scotroutes pointed out it has a 33t capacity. The GS M786 on my spitty has a capacity of 35t but I’m running 11-36/ 36/24 giving 37t with no problems

Looking at CRC the 105 medium mech has a 34t capacity and the long 105 mech has a 40t capacity.

Might just stick a longer chain on with the 11-36 and see if my current 105 mech will work. If my 105 is a long it should work but if it’s a medium I will only be 1t over.

Posted 10 years ago

bluearsedfly
Free Member

No worky worky.

Works on the large chain ring fine but as soon as it’s on the small chainring there’s not enough b screw adjustment to clear the 36t due to the odd way (which I can’t get my head around) in which the b screw adjustment works on the 105 mech. Tried a longer b screw but it just slips off the lip on the hanger.

Looks like I will have to try an XT mech, maybe even an 11-32.

Might have to raise the front mech slightly too as the chain now sits higher in the cage on the lower (larger) gears causing it to rub.

Posted 10 years ago

antigee
Free Member

“Tried a longer b screw but it just slips off the lip on the hanger”

seen it suggested that putting the b screw in the other way round helps – never had to try it though

Posted 10 years ago

back2basics
Free Member

yeah been down this route also, advice above is all sound….

Posted 10 years ago

TurnerGuy
Free Member

It is pretty cheap to buy a 34 ring for the front instead of your 36 – I have done it. That would help a bit.

Replacing the outer ring is a lot more expensive.

On my road bike I have a 32 cassette and the longer cage 105 mech, but it is not as ‘smooth’ as the 30 cassette on the cross bike, so if you can drop the front to 34 and get away with the shorter cage and the 30 cassette I think there are advantages.

Posted 10 years ago

bluearsedfly
Free Member

Good tip about turning the screw round, never thought of that!

Bit late as I picked up a XT mech on my travels today, have been thinking while I’m out and realised the barrel adjuster is on the 105 mech.

How do you adjust the tension on the XT mech as the 105 shifters don’t have any tension adjustment that I have seen/can remember?

Posted 10 years ago

PeterPoddy
Free Member

Is it me, or does it not seem more sensible, when talking about gear ratios like this, to just use a bloody mountain bike instead?

Hmmmmmmmm………….

Posted 10 years ago

bluearsedfly
Free Member

I got all excited then thinking someone was going to tell me how to tension my mech lol.

Posted 10 years ago

shedfull
Free Member

I got an 11-34 cassette working comfortably on a Specialized Roubaix but it was a long cage 105 mech and the longer of the two choices of Roubaix hanger. I think the longer hanger is about 28 or 30mm between axle and mech bolt centres. I’m sure a 36 tooth cassette would have worked just as well as the mech didn’t need much B-screw.

Posted 10 years ago

bluearsedfly
Free Member

Just been looking now and my 105 mech must be the short one, the jockey wheels are almost touching.

The jockey wheels on the XT GS are a good inch futher apart.

Posted 10 years ago

Nipper99
Free Member

9spd xt mech with a med cage is fine – its what i have on my gryphon with 105 shifters.

Posted 10 years ago

bookwyse
Free Member

I’m running an xt rear mech, 11-36 rear and triple on the front of my CDF. Use it for bike packing in Wales so the triple and 36 means lugging it all up hills is no a problem

Only way to get adjustment for the rear mech is to use an inline adjuster. I have mine close the shifters so I can make adjustments on the fly
Jeff

Posted 10 years ago

bluearsedfly
Free Member

Thanks. How did you tension it? Looking round the only way I can see is by adding an inline adjuster?

Posted 10 years ago

bluearsedfly
Free Member

Thanks Jeff, looks like you posted as I did! Inline adjuster it is then.

Posted 10 years ago

bluearsedfly
Free Member

Now all set up and running well with the gs mech and inline adjuster, thanks for everyones help.

Posted 10 years ago