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Sram Red comapct 50/34 to 50/38

BodyBody Posts: 32
edited March 2016 in Road general
I have a compact Sram 50/34 and will change it in 50/39. Will this work without shifting issues?

I am asking this because I tried a 39 from Stronglight but got shifting issues.

Hope somebody has good results with Sram 50-38

Posts

  • imposter2.0imposter2.0 Posts: 11,196
    I run 50/38 on a Force chainset, with a Stronglight inner. Works fine - in fact it works better than the original 34 as there is less of a jump to the 50 - not sure what shifting issues you have?
  • BodyBody Posts: 32
    Imposter wrote:
    I run 50/38 on a Force chainset, with a Stronglight inner. Works fine - in fact it works better than the original 34 as there is less of a jump to the 50 - not sure what shifting issues you have?

    I use 11 speed of Campagnolo. Is it possible that this will give issues ?
  • BodyBody Posts: 32
    Body wrote:
    Imposter wrote:
    I run 50/38 on a Force chainset, with a Stronglight inner. Works fine - in fact it works better than the original 34 as there is less of a jump to the 50 - not sure what shifting issues you have?

    I use 11 speed of Campagnolo. Is it possible that this will give issues ?

    The issues what i had with the 39T that my chain dropped between the chainrings. Hopefully it will works better with a 38 T chainring. LIke i said, i use 11 speed Campagnolo
  • FatTedFatTed Posts: 1,205
    I use SRAM Red Quarq 50/34 with Campagnolo everything else, no issues, never had the chain drop between the rings, fallen off the inner one a few times.
  • BodyBody Posts: 32
    FatTed wrote:
    I use SRAM Red Quarq 50/34 with Campagnolo everything else, no issues, never had the chain drop between the rings, fallen off the inner one a few times.

    50/34 is standard what has to work. I am curious if 50/38 compact works as well without shift issues.
  • Escher303Escher303 Posts: 342
    Body wrote:
    Body wrote:
    Imposter wrote:
    I run 50/38 on a Force chainset, with a Stronglight inner. Works fine - in fact it works better than the original 34 as there is less of a jump to the 50 - not sure what shifting issues you have?

    I use 11 speed of Campagnolo. Is it possible that this will give issues ?

    The issues what i had with the 39T that my chain dropped between the chainrings. Hopefully it will works better with a 38 T chainring. LIke i said, i use 11 speed Campagnolo

    Did you put the inner chainring on the right way around? If you put it on backwards (and it is difficult to tell with some chainrings which is the proper way) then the gap will be very slightly larger (but hard to see by eye) and can result in the chain dropping between the two. Put on the right way this doesn't happen. I don't think your issue was with using a 39 ring.
  • BodyBody Posts: 32
    Thanks for your comment. I asked Stronglight how to fit and its correct with the letters outside
  • BodyBody Posts: 32
    Thanks for your comment. I asked Stronglight how to fit and its correct with the letters outside
  • StillGoingStillGoing Posts: 5,207
    Body wrote:
    Thanks for your comment. I asked Stronglight how to fit and its correct with the letters outside

    Letters outside doesn't mean away from the bike just in case that is your thinking. If the chain is dropping between the chainrings, I doubt it is anything other than you have one of them the wrong way around.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • BodyBody Posts: 32
    Body wrote:
    Thanks for your comment. I asked Stronglight how to fit and its correct with the letters outside

    They send me also a picture, so I could notice the letters on the out side way
  • MikeBrewMikeBrew Posts: 814
    The ramping on the 50T will be designed and angled to deliver the chain neatly onto the teeth of the smaller diameter 34T chainring. Using a 38 or 39 tooth ring in conjunction with this 50, you will have no effective ramping, hence the gap into which the chain can drop.
    It will be hit and miss, sometimes it'll shift fine but will drop between the rings on other attempted shifts. This is because the larger diameter of the 38/39 T means that the teeth are too high up the ramping, and hence too far away from the 50T ring.
  • super_davosuper_davo Posts: 602
    I've made exactly the same change on my Ultegra equipped bike and can confirm re the ramping.
    It seems to ramp too high when shifting to the outer chainring, which isn't surprising as the chain is starting higher up.
    On the first ride had dropped chains on the outside of the outer ring. This was sorted by reducing the limit settings so it didn't shift across so far. I hadn't altered the settings from the original rings and it probably always shifted further than it needed to, but no dropped chains because the chain engaged correctly.
    I've now got it working OK, shifts down are perfect but shifts up are nowhere near as smooth as before.
    I think long term I will just buy a 53/39 but the 38 inner ring is a good short term compromise. I found in Essex riding 34 was just massive overkill and hardly ever used it, too big a gap between rings. Can't fully ditch the compact as I need it for when I ride at my parents house in the peaks.
  • BodyBody Posts: 32
    How does it comes that it works for some and not for everybody?
    Has Sram force/Red made difference types of chain rings over the time?
  • Can't really answer your question but......... I've got the current SRAM red 36/52 chainset. I put a 38t inner chainring on for a bit and the shifting wasn't so good. It was good but shifts weren't as instant as running the 36 ring. Back to running the 36t nowadays.
  • BodyBody Posts: 32
    Today I will get a new 38T of Sram Red. How to mount this, with letters outside/inside and are there special marks on the ring?
  • StillGoingStillGoing Posts: 5,207
    Body wrote:
    Today I will get a new 38T of Sram Red. How to mount this, with letters outside/inside and are there special marks on the ring?

    The rings have a recess for the bolt heads. That has to face away from the outer chainring otherwise you'll mount the chainring slightly away creating the gap for the chain to fall into. So letters towards the frame for the inner ring so you can read them from the left side of the bike.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • BodyBody Posts: 32
    philthy3 wrote:
    Body wrote:
    Today I will get a new 38T of Sram Red. How to mount this, with letters outside/inside and are there special marks on the ring?

    The rings have a recess for the bolt heads. That has to face away from the outer chainring otherwise you'll mount the chainring slightly away creating the gap for the chain to fall into. So letters towards the frame for the inner ring so you can read them from the left side of the bike.

    Thank you for your clear answer. Hope the new combination of 50-38 will works.
  • BodyBody Posts: 32
    Body wrote:
    philthy3 wrote:
    Body wrote:
    Today I will get a new 38T of Sram Red. How to mount this, with letters outside/inside and are there special marks on the ring?

    The rings have a recess for the bolt heads. That has to face away from the outer chainring otherwise you'll mount the chainring slightly away creating the gap for the chain to fall into. So letters towards the frame for the inner ring so you can read them from the left side of the bike.

    Thank you for your clear answer. Hope the new combination of 50-38 will works.


    ON the Ring is also a kind of 'peak', how to mount the Ring in connection wit this peak, see picture. I was supposing by the hidden bolt but is it at the left or right side of the hidden bolt? On the bigger ring I cant see any mark.

    sbswvn.jpg
  • StillGoingStillGoing Posts: 5,207
    It won't make any difference as it is on the inside of the ring.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • BodyBody Posts: 32
    philthy3 wrote:
    It won't make any difference as it is on the inside of the ring.

    okay thanks

    So far the chain dont drop between the rings on the bike-standard. As soon as it stops raining I will make a test ride outside.
  • MikeBrewMikeBrew Posts: 814
    Body wrote:


    ON the Ring is also a kind of 'peak', how to mount the Ring in connection wit this peak, see picture. I was supposing by the hidden bolt but is it at the left or right side of the hidden bolt? On the bigger ring I cant see any mark.

    sbswvn.jpg

    This is an alignment mark. On a non hidden bolt crankset, this mark should be aligned with/behind the crank arm. On a hidden bolt crankset, it should be positioned at 180 degrees(i.e. opposite) to the crank arm.
    The bigger (outside) ring aligns with the crank arm by way of a pin on the outside, which prevents the chain dropping between it and the crank arm.
  • BodyBody Posts: 32
    MikeBrew wrote:
    Body wrote:


    ON the Ring is also a kind of 'peak', how to mount the Ring in connection wit this peak, see picture. I was supposing by the hidden bolt but is it at the left or right side of the hidden bolt? On the bigger ring I cant see any mark.

    sbswvn.jpg

    This is an alignment mark. On a non hidden bolt crankset, this mark should be aligned with/behind the crank arm. On a hidden bolt crankset, it should be positioned at 180 degrees(i.e. opposite) to the crank arm.
    The bigger (outside) ring aligns with the crank arm by way of a pin on the outside, which prevents the chain dropping between it and the crank arm.

    So it has to be on this way

    6qktwl.jpg
  • MikeBrewMikeBrew Posts: 814
    Assuming your crank set is hidden bolt, yes.
  • StillGoingStillGoing Posts: 5,207
    MikeBrew wrote:
    Assuming your crank set is hidden bolt, yes.

    Well, learnt something new myself there.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
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