50 crank with 28T ok?

Ask for advice or share your fettling tips
blackstick
Posts: 136
Joined: Mon Mar 19, 2012 19:27 pm

50 crank with 28T ok?

Postby blackstick » Thu Jan 03, 2013 21:47 pm

My current setup is 50/34 with a 11/28 cassette. 10 speed.

Previously I used an old Ultegra 9 speed rear derailleur with the 11/28 and it shifts good.
Bought a 10 speed new 105 rear derailleur from CRC then fitted. It shifts good, but chain just kept on hitting the rear derailleur cage not matter how I tune it.
Both of it is a short cage derailleur with the 105 cage being slightly longer...
Took it to a bike shop, they said I should not run a 50 with a 28...
I know that from the Shimano tech, but I did not have any problem with an old 9 speed derailleur which does not support the bike shop opinion.

Wonder what has happened? Chain too short? I have 53 links at the moment and it is a 10 speed chain.

Dave_P1
Posts: 471
Joined: Tue Dec 28, 2010 11:27 am

Re: 50 crank with 28T ok?

Postby Dave_P1 » Thu Jan 03, 2013 22:07 pm

I run a 50/34 and a 11-28 cassette on the back without any problems so I'm not sure what the shop is talking about here.
I also run a 105 short cage rear mech.

User avatar
Escadrille Ecosse
Posts: 174
Joined: Wed Jul 20, 2011 19:33 pm

Re: 50 crank with 28T ok?

Postby Escadrille Ecosse » Thu Jan 03, 2013 22:30 pm

I also run an 11-28 with a 50/34 and short cage 105, both 5600 and 5700, without issues
Coffee is not my cup of tea

Moda Fresco track racer
Kinesis Crosslight Pro 6 winter commuter
Gunnar Hyper X
Rocky Mountain ETSX
Cannondale Scalpel 3000 (retro-bike in bits)
Lemond Poprad Disc, now retired pending frame re-paint.

User avatar
smidsy
Posts: 5256
Joined: Tue Jan 17, 2012 20:52 pm

Re: 50 crank with 28T ok?

Postby smidsy » Fri Jan 04, 2013 09:17 am

What they mean is you should not cross chain (big front big rear) as this creates excessive wear.

If you are cross chaining some set ups will not be able to eliminate chain rub no matter how much you twiddle the settings.

Best to avoid the practice of cross chaining altogether (as you LBS states)
Yellow is the new Black.

blackstick
Posts: 136
Joined: Mon Mar 19, 2012 19:27 pm

Re: 50 crank with 28T ok?

Postby blackstick » Fri Jan 04, 2013 14:37 pm

smidsy wrote:What they mean is you should not cross chain (big front big rear) as this creates excessive wear.

If you are cross chaining some set ups will not be able to eliminate chain rub no matter how much you twiddle the settings.

Best to avoid the practice of cross chaining altogether (as you LBS states)


Now I see, so its best to keep the 28T for the small crank.

User avatar
Rolf F
Posts: 13584
Joined: Sun Oct 26, 2008 09:29 am

Re: 50 crank with 28T ok?

Postby Rolf F » Fri Jan 04, 2013 15:27 pm

What the shop is probably really getting at is that the overall range of gears you want is outside Shimanos recommendation. In practice, you can normally get away with it - but no guarantee. And that means potentially everything could jam up if you end up in big - big.

However, I would probably choose not to set up a bike where this was a problem. It's all very well saying 'don't use big big' but you don't want to risk the bike if it does happen. I'd certainly want to test big big and if there was a problem, try again with a couple more links in the chain - which might fix the problem.

As it happens, I do tend to accidentally cross chain a fair bit but generally the other way - if you are on a fast descent in top gear and come round a corner to an unexpected steep climb, the first thing you'll want to do is drop to the smaller chainring - so you end up in small-small. The big - big equivalent would be topping a hill and finding a steep descent on the other side. Here you probably won't need to panic and shift the chainring first!
Faster than a tent.......

User avatar
smidsy
Posts: 5256
Joined: Tue Jan 17, 2012 20:52 pm

Re: 50 crank with 28T ok?

Postby smidsy » Fri Jan 04, 2013 18:12 pm

blackstick wrote:
smidsy wrote:What they mean is you should not cross chain (big front big rear) as this creates excessive wear.

If you are cross chaining some set ups will not be able to eliminate chain rub no matter how much you twiddle the settings.

Best to avoid the practice of cross chaining altogether (as you LBS states)


Now I see, so its best to keep the 28T for the small crank.


Yes, similarly at the other end of the scale do not use the smallest (12 or 11 or whatever you have) when in the small front chainring.

So avoid big/big and small/small.
Yellow is the new Black.


Return to “Workshop”

Who is online

Users browsing this forum: Andcp, martinperry and 5 guests