SRAM Front Derailer Trouble

jimcameron

Hi Guys,

I have a SRAM Force Shifter and a Rival front derailer.

I've been having alot of trouble recently shifting up into the big chainring. And for some reason i can only shift up once i i am in the smallest sprocket.

I've been playing around with the tension of the cable. To me it seems too tight however if i loosen it off it a very small amount it won't shift at all. It seems too tight as when i do eventually get into the big ring and i click down one gearfor the the front (i.e. the middle trim gear) it doesn't do anything until i click down again and shoots over with a big bang. i.e. with all the tension in the cable. However still when i try to shift up it's delayed in getting there and is not smooth at all (if it even manages to get to the big ring)

If you could help on my SRAM nightmare then please do.

Cheers
Jim

Evil Laugh

Dunno if it will help you but my lbs in setting up my force fd had to set it much higher to get decent shifting than what they were used to doing. It would always be fine in the stand but useless on the road until they repositioned the fd.

topdude

Sounds like the limit screw for the big ring is stopping the mech from engaging when you change to the big ring.
I would disconnect the cable from the mech and start again.
With the chain on the small chainring and large rear sprocket adjust the lower limit screw so there is a 1mm gap between inner rear plate of the mech and the chain.
Now reconnect the cable (gear lever in small ring position) and while pulling hard on the cable to take up any slack tighten the clamp.
Now back off the upper limit screw so it cannot affect the shifting.
Shift the chain to the middle of the cassette just to make adjusting easier.
Adjust shifting to the large ring with the cable adjuster if you have one.
It should go straight to the big ring with one click of the lever.
When the shifting is correct move the chain to the big ring and small sprocket on the cassette.
Now adjust the outer limit screw so it does not quite touch the mech when shifting up to the big ring

jimcameron

sorry to bring this one up again. topdudes instructions where perfecto.

In the stand my mech shifts perfectly, except as soon as i'm on the bike and riding it won't shift at all. i see there's movement but not enough to shift?

Has anybody encountered this before? I even jumped off at the lights today and stuck it on my should er to check that my flatmates hadn't sabotaged me. On the should it was perfect. On the road it doesn't work...

keef66

That sounds scary. Suggests that your weight on the bike is having a profound effect on shifting. In that case I'd stop riding the thing and be checking the frame very carefully to see if it's failed somewhere. If the frame's OK, is there play in the BB / crank area??

pbt150

I actually get exactly the same thing - it shifts fine when the bike's in the stand, but when I go for a ride I actually have to stop pedalling completely as I shift, then gingerly turn the cranks until is goes up to the big ring. I'm using Rival mech and derailleur.

What chain rings/chainset are you using? I sort of bodged my build when I saw a 9 spd FSA SLK carbon crankset on CRC for £60 - my LBS reckon this might be the problem and I'm going to see if I can borrow some 10 spd chainrings off someone to see if this fixes it.

jimcameron

yeah i'm using both rival mechs and a FSA compact crankset. I didn't realise that there was such a thing as 9 speed cranks and 10 speed cranks.

pbt150

You do get chainsets in different 'speeds', but in general they are fairly compatible so it's not normally an issue.

I actually found some info on another forum about using a FSA chainset with SRAM, and most of it wasn't very complimentary. On my bike at least, the mech moves far enough that it SHOULD change rings, so I've narrowed it down to one of the following, which are either because it's FSA, or because it's 9spd:

-chainrings are spaced too far apart
-chainrings are too wide
-ramps/pins aren't right for 10spd
-chain and chainset don't agree with each other (for whatever reason)

ds690

Two Suggestions:

1. If you are using a shimano chain, some are directional and you may have the chain backwards.

2. Front shifting is not meant to be done under power. The load is on the top side of the chain under power and will prevent the chain from being lifted onto the big ring. You need to pedal easy for a moment until the chain has been lifted onto the big chainring.

mrjerome10

try the limit screws

jimcameron

Well it turns out i hadn't had it as perfect as i first thought.

Firstly i though i had the height correct (i.e. between 1-3mm). A tip a picked up was to disconnect the cable and pull out the cage so that the out edge is inline with the big ring. you should be able to stick in a two pence piece between bottom of cage and one big ring tooth at the front of the derailler with the out plate and the big ring alligned. So it was a bit to high up.

Secondly my outer limit was to close to the big ring and thus preventing the chain from getting up into big ring. I tried to limit it so that when it was in the big ring i can run through all the gears without sraping the cage (as is the SRAM design). So i opened it out a bit and now it is perfect.

I have finally cracked it! RELIEF!

jimcameron

Well it turns out i hadn't had it as perfect as i first thought.

Firstly i though i had the height correct (i.e. between 1-3mm). A tip a picked up was to disconnect the cable and pull out the cage so that the out edge is inline with the big ring. you should be able to stick in a two pence piece between bottom of cage and one big ring tooth at the front of the derailler with the out plate and the big ring alligned. So it was a bit to high up.

Secondly my outer limit was to close to the big ring and thus preventing the chain from getting up into big ring. I tried to limit it so that when it was in the big ring i can run through all the gears without sraping the cage (as is the SRAM design). So i opened it out a bit and now it is perfect.

I have finally cracked it! RELIEF!

dizzydane

Well done!

I had the same problem last year with my bike and it took 3 months of playing and bike shop trips to set it up correctly.

Not impressed with SRAM though. Don't know about you, I bent the teeth on my chain ring while I had problems changing up...

- Can you get your back wheel out without the rear derailleur catching?

hopper1

dizzydane wrote:

Well done!

I had the same problem last year with my bike and it took 3 months of playing and bike shop trips to set it up correctly.

Not impressed with SRAM though. Don't know about you, I bent the teeth on my chain ring while I had problems changing up...

- Can you get your back wheel out without the rear derailleur catching?

Just push down/in on the bottom of the rear mech (where it meets the cage), this should help facilitate wheel removal/fitting...