# Sram big ring and large sprocket.



## davidjks (Aug 20, 2008)

SRAM publicity is vague on this but can anyone confirm that it's possible to run a chain on a 50 (or 53) chainring onto a 25 -32 rear sprocket? My experience with Aeroglide is that on a 50 ring and anything bigger than 22 sprocket the chain fouls the outside rear cage and the chain in effect comes off the lower pulley.


----------



## Marc (Jan 23, 2005)

What cage length? Medium cage length should be able to wrap 37t difference whereas the shortie can only handle 32t.


----------



## davidjks (Aug 20, 2008)

It's medium length. But thats not the issue, it's at the other end, large chainring, 50 and large sprocket, 25 at the moment with thoughts of a 27.


----------



## Mike T. (Feb 3, 2004)

A lot of it depends on chainstay length. With my old frame I couldn't get all 10 cogs without chain rub. With my new frame (longer chainstays) I can. Not that I ever use big-big or small-small on purpose.


----------



## davidjks (Aug 20, 2008)

Like you for years I have avoided big-big and small-small but Contador with a wi-fli rear mech seems to have the flexibility to go big-big which can be useful to pull up small humps on a generally flat road.


----------



## Mike T. (Feb 3, 2004)

davidjks said:


> Like you for years I have avoided big-big and small-small but Contador with a wi-fli rear mech seems to have the flexibility to go big-big which can be useful to pull up small humps on a generally flat road.


With Ultegra 2 generations old I have the ability but the visual effect of the chainline (squat down behind the bike and look!) is enough to stop me from ever using it.


----------



## tednugent (Apr 26, 2010)

davidjks said:


> SRAM publicity is vague on this but can anyone confirm that it's possible to run a chain on a 50 (or 53) chainring onto a 25 -32 rear sprocket? My experience with Aeroglide is that on a 50 ring and anything bigger than 22 sprocket the chain fouls the outside rear cage and the chain in effect comes off the lower pulley.


Isn't that the point of SRAM WiFLi? compact crank (50-34T) with a 11-32T cassette?


----------



## davidjks (Aug 20, 2008)

Yes indeed. But I need some reassurance that it will work before I buy a wifi mech. Certainly 50/25 with aero glide doesn't.


tednugent said:


> Isn't that the point of SRAM WiFLi? compact crank (50-34T) with a 11-32T cassette?


----------



## cxwrench (Nov 9, 2004)

davidjks said:


> Yes indeed. But I need some reassurance that it will work before I buy a wifi mech. Certainly 50/25 with aero glide doesn't.


Yes, it does work. So does WiFli. I just installed another one last week, compact w/ 11/32. Worked perfectly in in big/big. If yours doesn't work there is some other issue.


----------



## davidjks (Aug 20, 2008)

Well thanks for that - I'll just have to grit my teeth and buy a WiFli changer. Again many thanks.


----------



## thehook (Mar 14, 2006)

I had the a 53/32. I ran an Apex medium cage on the back. And it worked smooth!


----------



## Camilo (Jun 23, 2007)

I have a regular old short cage Red RD, a 50/34 Red crankset, and an 11-28 cassette. I have no problems running the 50-28 combination. Sram sells the 11-28 cassette in the "Red" lineup, why would they sell a cassette that wasn't compatible with a Red drivetrain (with short cage RD), and therefore any Sram drive train?

Just FWIW, like the guy above, the chain line is so askew on that combination that I tend to avoid it just because it causes my OCD traits to kick in. But there's no chain rub on the FD (trimmed of course).


----------

