Medium or long cage rear mech?
I have an 07 Sworks stumpi and have always just banged on a long cage rear mech.
I'm running an 11-34 cassette so would it be possible to run a medium sram mech on that
Thanks guys.Posted 10 years ago
My Pitch came with a 11-34 cassette, 22,32,44 rings and a medium cage mech. It works perfectly.
I can't see any reason why they still make long cage mechs, TBHPosted 10 years ago
Posted 10 years ago
If you're running a triple up front, then you can see from the chart that a GS mech will lose you your 5 tallest gears on the granny ring, and your tallest gear on the middle ring due to the chain being too slack.
The longer cage length is basically necessary to pick up the slack when you're running combos with small sprockets back and front, while allowing sufficient chain length to wrap around the large combos. ie you need sufficient chain length to wrap round 44 front/34 rear, but when you drop to 22/20 the cage needs to be long enough to keep the chain in tension.Posted 10 years ago
Vinny, that's for a Shimano SHORT CAGE mech, not a a SRAM MEDIUM CAGE though! 🙂Posted 10 years ago
Actually, SRAM medium has capacity of 37, so you'd lose the top 4 gears when in the granny.Posted 10 years ago
so you'd lose the top 4 gears when in the granny.
I never noticed that. But if you're in the granny, what are you doing at the small end of the block anyway? 😀
Spesh supply plenty of bikes set up like this (AS do others I guess) so it must be OK 🙂Posted 10 years ago
I can't see any reason why they still make long cage mechs
+ 1Posted 10 years ago
They make long cage rear mechs so that the chain can be made long enough not to snap your rear mech off when someone who doesn't know not to do it, runs big ring, largest sprocket. It's something we learn not to do but beginners tend to be ignorant of that fact.Posted 10 years ago
Yes, go medium. Just be aware that you don't want to put your chain in a small chainring/ small sprocket combo and you should be alright – as PP, I have a 22/32/44; 11-34 drivetrain with a medium-cage mech and have no problems.Posted 10 years ago
As PeterPoddy says, what are you doing in the granny ring and messing around at the small end of the cassette anyway?
Besides, the worst thing that can happen in this situation is the rear mech folds back far enough for the chain rubs against itself and goes a bit slack which isn't dangerous.
I have a 11-34 44/32/22 set up with a Shimano medium cage and don't get any problems.
Go medium cage and save yourself an easy 80 gramms. Its also a slicker shift as less mass on a lever and a smaller target for vegetation and flying rocks.Posted 10 years ago
runs big ring, largest sprocket.
No problem at all. 🙂
If your chain's too short, it's too short. End of. and it won't make a jot of difference what mech you've got on!Posted 10 years ago
Yeah, I think you're a bit confused there geetee1972.
You set your chain length up as per the bottom of vinnyeh's first post and all Shimano documentation – largest sprocket and largest chain ring plus 2 links. This means you won't snap your rear mech off when running biggest front and back whatever length of cage you have.
The non-issue comes when running small sprockets and chain ring at the same time. The mech has to take up the links that are not now running over teeth. But as experience has shown, there isn't a problem with a medium cage despite what the teeth ratings would suggest.
I think it's safe to conclude that SRAM and (even more so) Shimano are conservative with the teeth ratings of their rear mechs. This is probably to allow for people who set up their chain length with more than the specified 2 extra links (either because they don't know any better or so thay can remove a link if the chain snaps and the pin is lost?).Posted 10 years ago
have gone for the medium, especially as Crc have xo mechs for £119.
I'm a time served vet so understand how to use my gears correctly to keep the chainline straight and avoid extremes.
CheersPosted 10 years ago
For the record a Sram med cage XO mech will work 11-34 / 22-32-44 a treat.
However, it won't work with Shimano shifters which I'm amazed that I either didn't know or research.
So popped down to my LBS and plumped for an XTR Shadow instead.
Disappointed that Id have to change my whole setup to run a nice mech. But next upgrade time I think I'll go over to Sram as on closer inspection their kit is extremely well put together and is "prettier" too.Posted 10 years ago
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