SRAM Long vs Medium cage - Stumpy FSR 2010

Chris`I

Hey all,

Looking for a quick bit of advice. I need a new mech for my Stumpy FSR '10. I was looking to upgrade from my SRAM X9 to X0, however I am unsure as to the cage length I should go for. I beleive the current X9 is a long cage, which makes sense having a triple up front, but the 2010 FSR expert which has X0 has a "mid" cage according to the specs.

According to my calculations, I would lose the bottom 3-4 gears at the rear when in the smallest chainring at the front if I used a med cage vs long cage. Is that the case on the OEM setup for the FSR expert which has it by default or is there room for manouver in which case it works fine? Find it odd that Spesh would have a model that couldnt use all the gears (forgetting about not using small/small for now)?

Here are the details:

My Spesh Stumpy FSR comp:
Rear Derailleur: SRAM X-9, 9-speed, long cage
Chainset: Custom Shimano FC-M542, 175mm
Chainrings: 44/32/22 tooth chainrings
Cassette: Shimano HG61, 9-speed, 11-34 tooth range
Chain: SRAM PC-971, 9-speed with Power Link
Rear Susp: 7.875x1.9 inch

Spesh Stumpy FSR Expert
Rear Derailleur: SRAM X.0 9-speed, mid cage
Chainset: Custom Shimano FC-M762 , 2piece, 175mm
Chainrings: 44/32/22 4 bolt tooth chainrings
Cassette: Shimano HG61, 9-speed, 11-34 tooth range
Chain: SRAM PC-971, 9-speed with Power Link
Rear Susp: 7.875x1.9 inch

All the variables that you usually take into consideration are shared between the 2 models except for rear mech. The reason I ask is I can get the med cage £50 cheaper than the long cage.

TIA
Chris

nicklouse

looked in the FAQs?

it tell you how to work out your range and what the ange of the mechs are.

http://www.bikeradar.com/forum/viewtopic.php?t=12546123

Chris`I

Yes read the FAQ - which would suggest a long cage mech to get all gears and that a medium cage I will loose 4 gears in the smallest ring.

My question is why does Specilized spec up an almost identical bike to mine with a medium cage mech with X0 while they use a long cage on X9? And if it will work fine, then I can save myself £50 and get the medium. Not sure Spesh would spec a bike knowingly with some gears unusable? Or do they assume that more experienced bikers wouldnt go near those combo's anyway?

Chunkers1980

Do you know that you have exactly the same gap front and rear.

Talking about losing gears makes me think not (and not fully understanding how it works)as it's not a matter of gear numbers, it's the actual numbers of teeth on the cogs

Chris`I

OK so yes you dont lose them as such but they chain will be loose and whip around as you dont have the correct chain tension because the mech cant take up the slack, and technically you should be using a long cage accoridng to the specs.

The questions still stands though, do you get the right tension in those gears from a medium cage as Specialized have done, or are they unusable with the amount that the chain would be loose?

Chunkers1980

You need to answer the question. What front rings do you have and what range to you run on your cassette. That will give you the answer as mechs have a max difference in teeth in the cogs that they will handle.

Chris`I

Specs are up the top. Both my bike (with X9 long) and the other Stumpy with the XO (medium) run the same 44/32/22 up front and 11-34 out back. Also both have the same suspension movement (for chain growth) so should have the same size chains.

According to the FAQ that means I need a long cage mech as 22/11 combo requires 45 slack capacity to take up.

BUT if that is the case, how come Specialised run a medium cage on the Stumpy FSR Expert as that can only handle 37.

jayson

Ive just had the X9 rear mech on my remedy replaced under warranty and i got a medium cage instead of a long, it all works beautifully and smooth and im over the moon cause i always run a medium or short cage mech on my bikes with no probs.

Currently im runnin an 44-32-22 up front with an 11-34 cassette and it works beautifully, i dont (and neither should anyone) use the extreme crossover gears and i have zero problems with regards to chain length or anything else aslong as ur sensible.

ride_whenever

I run a short cage x0 with a triple and it seems to work fine...

Just about keeps the chain tight in the winch gear.

Chris`I

Thanks guys, I've just pulled the trigger on a medium cage, so hopefully it will all work nicely together

Chunkers1980

Yeah they prob understate the range a mech will actually do when they specify it - stating the mech will work optimally within a range.

My XTR Shadow (longest Shim cage) will run in every combo and keep reasonable tension in small/small - I suspect this will not be the case with a medium cage setup, but may work for you.

supersonic

There is no reason to use small/small or similar really.