Sram Red compact compatible Stronglight ?

[Body]

I have a compact crank Sram Red 50-34 and bought a new Stronglight 39 T.

Now i got problems with the front derailleur. I have adjust man times the derailleur without succes. As soon as I make test ride I get problems with shifting up and the chain will also drop between the large and small chains.

Now I am wondering if Sram chainring will work with Stronglight as compact crank?

[Devon]

Are you using the 39t as your inner ring?

Did you mount it with the same bolts, and in the same orientation as the previous ring?

[Body]

Are you using the 39t as your inner ring?

Did you mount it with the same bolts, and in the same orientation as the previous ring?

The 39 t is the inner ring of Stronglight .
I used the same bolts and on Stronglight are no marks for orientation. I used both sides of the ring of Stronglight, with the letters in site and out site without succes.

[Devon]

It sounds as though the inner ring may be too inset, but it's hard to tell.

Could you post some photos?

[Body]

It sounds as though the inner ring may be too inset, but it's hard to tell.

Could you post some photos?

[Devon]

Looks like you need to adjust your derailleur limit screws and/or get a chain catcher.

Maybe someone else has better knowledge of the specific parts.

[Body]

Looks like you need to adjust your derailleur limit screws and/or get a chain catcher.

Maybe someone else has better knowledge of the specific parts.

Thanks
I have adjust the derailleur on all kind of positions. I am afraid Sram wont work together with Stronglight

[Devon]

A chainring is a chainring. I expect the issue is more likely due to the increase in ring size, but I'm not sure how to solve it.

[Body]

A chainring is a chainring. I expect the issue is more likely due to the increase in ring size, but I'm not sure how to solve it.

What you mean with ring size?

[wpccrunner]

I tried a similar experiment, tried all different sorts of derailleur adjustments and ended up with the same issue as you. I have Praxis 52x36 rings, and tried to swap the 36 for a KCNC 39T inner ring. The up shift from small to large ring was completely fine, however down shift from big to small, the chain would not properly engage with the 39T, (it would get stuck "hovering" on top of the 39T)

I concluded this is because the the 52T (50T in your case) was not designed to shift onto a chain ring with such a larger diameter (39T is approximately a 6.2 inch diameter, where a 34T is approximately a 5.41 inch diameter). Chain rings are typically designed to work as a system. Usually* you can get away with mixing and matching sizes from the same company but when you have mixed sizes and mixed companies things tend to work less than perfect.

I have successfully used FSA rings as a 50x34, 50x36, 52x36, and 52x38. However, when I tried a 50x38 the chain would get stuck in between the rings "hovering/floating" on top of the small ring when I down shifted. And to note, both the 50T and 38T were FSA rings on an FSA crank. The 50T is just not designed to work 100% with a ring of that size.

Curious as to why you need a 39T inner ring when your outer ring is only a 50T? You could try installing a SRAM Powerglide 38T ring to see if that helps, but from my experience with this combo using FSA rings I would expect the shifting to still have issues. If you really want a larger inner ring, you will most likely have to get a larger outer ring.

This is all just in my experience so take it as you wish. Maybe someone else with more experience or better luck can chime in.

[Body]

I tried a similar experiment, tried all different sorts of derailleur adjustments and ended up with the same issue as you. I have Praxis 52x36 rings, and tried to swap the 36 for a KCNC 39T inner ring. The up shift from small to large ring was completely fine, however down shift from big to small, the chain would not properly engage with the 39T, (it would get stuck "hovering" on top of the 39T)

I concluded this is because the the 52T (50T in your case) was not designed to shift onto a chain ring with such a larger diameter (39T is approximately a 6.2 inch diameter, where a 34T is approximately a 5.41 inch diameter). Chain rings are typically designed to work as a system. Usually* you can get away with mixing and matching sizes from the same company but when you have mixed sizes and mixed companies things tend to work less than perfect.

I have successfully used FSA rings as a 50x34, 50x36, 52x36, and 52x38. However, when I tried a 50x38 the chain would get stuck in between the rings "hovering/floating" on top of the small ring when I down shifted. And to note, both the 50T and 38T were FSA rings on an FSA crank. The 50T is just not designed to work 100% with a ring of that size.

Curious as to why you need a 39T inner ring when your outer ring is only a 50T? You could try installing a SRAM Powerglide 38T ring to see if that helps, but from my experience with this combo using FSA rings I would expect the shifting to still have issues. If you really want a larger inner ring, you will most likely have to get a larger outer ring.

This is all just in my experience so take it as you wish. Maybe someone else with more experience or better luck can chime in.

Thanks of your information.
I took a 39T because it would be similar to a double and when going to the mountains i would swap a 34 t. I understand I could better use a 38 of Sram but because of your expierences 50-38 will give also issues.
Is it maybe better to use 52 T (stronglight) with the 39 T?

Has anybody here good results with 50-38 Sram?

[stormur]

I use/ used various combinations of stronglite rings on Rotor crank. Works fine. With Ultegra 6800, Sram Force22, Campagnolo Chorus '14, Record '15. No issues. It's small ring... your FD adjustment is a reason of issues, not rings. With 1 exception : on every ring you have "desired" combination : on 39 is 52/53, not 50... .

Edit : Stronglite HAS "markings" : logos has to be exactly opposite crank arm

[Body]

I use/ used various combinations of stronglite rings on Rotor crank. Works fine. With Ultegra 6800, Sram Force22, Campagnolo Chorus '14, Record '15. No issues. It's small ring... your FD adjustment is a reason of issues, not rings. With 1 exception : on every ring you have "desired" combination : on 39 is 52/53, not 50... .

Edit : Stronglite HAS "markings" : logos has to be exactly opposite crank arm

Thanks,
And does work 50/38?

[stormur]

I always use/d recommended combination :

34-46
36-46
34-50
36-52
38-52

BUT : most CX setups in pro racing ( man ) is 39-46 , so obviously just 7t difference is not an issue there (?).

Do I see Campagnolo FD ???

[Body]

I always use/d recommended combination :

34-46
36-46
34-50
36-52
38-52

BUT : most CX setups in pro racing ( man ) is 39-46 , so obviously just 7t difference is not an issue there (?).

Do I see Campagnolo FD ???

yes, I use Campi and Sram crankset