Sram force rear mech issue

Muckers · 07-08-2015 9:07pm #1

Hi tonight while out on a spin, I could not move the chain up onto a bigger sprocket on my rear cassette while climbing. No problem going the other way though. I thought it must be the shifter but after removing the gear cable from the rear mech and checking to see if the shifter is pulling and releasing the cable, all was fine. I reconnected the gear cable and same thing. The cable cannot pull the mech up onto a bigger sprocket. This mech is only a few months old and coincidentally the gearing has never been great since I installed it. I will contact bike discount for a replacement, but any advice in the meantime?

onthefringe · 07-08-2015 9:11pm

Muckers wrote: »

Hi tonight while out on a spin, I could not move the chain up onto a bigger sprocket on my rear cassette while climbing. No problem going the other way though. I thought it must be the shifter but after removing the gear cable from the rear mech and checking to see if the shifter is pulling and releasing the cable, all was fine. I reconnected the gear cable and same thing. The cable cannot pull the mech up onto a bigger sprocket. This mech is only a few months old and coincidentally the gearing has never been great since I installed it. I will contact bike discount for a replacement, but any advice in the meantime?

are you sure the mechanism in the shifter is not slipping under load?
hard to replicate it with the cable removed

Muckers · 07-08-2015 9:34pm

onthefringe wrote: »

are you sure the mechanism in the shifter is not slipping under load?
hard to replicate it with the cable removed

Hadn't thought of that, although with the cable removed the shifter pulls the cable while I am pulling against it.

Eamonnator · 07-08-2015 9:39pm

I have found, that Sram Force has little tolerance for dirt.
I suggest the following:
Shifters: Clean well with WD40 or similar. Don't be afraid to use lots of it, you may be surprised at the amount of gunk, that is flushed out. Dry the shifters as well as you can. Lubricate well. I use a lubricant with teflon.
Mech.: Clean and lubricate.
Cables: If you can, replace the inners, flush any dirt from the outers. If you think the inners are OK, try and get some lubricant into the outer cables.

onthefringe · 07-08-2015 9:41pm

Muckers wrote: »

Hadn't thought of that, although with the cable removed the shifter pulls the cable while I am pulling against it.

pressure of your hand wouldnt replicate the force required to move the mech up the block under load no matter how lightly you may be pedaling ..

re connect cable and just watch to see if the rear mech makes an effort to move whilst pedalling before slipping
be unusual for a mech to hinder shifts.. its only a spring and an arm in simple terms..
nothing is impossible though!!

Muckers · 07-08-2015 9:46pm

Eamonnator wrote: »

I have found, that Sram Force has little tolerance for dirt.
I suggest the following:
Shifters: Clean well with WD40 or similar. Don't be afraid to use lots of it, you may be surprised at the amount of gunk, that is flushed out. Dry the shifters as well as you can. Lubricate well. I use a lubricant with teflon.
Mech.: Clean and lubricate.
Cables: If you can, replace the inners, flush any dirt from the outers. If you think the inners are OK, try and get some lubricant into the outer cables.

Mech and cables shouldn't be an issue dirt wise. Mech is very clean and inner and outer gear cables are new.
I forgot to say that I can push the mech inwards no problem when the cable is removed while turning the pedals.
Will I need to remove the shifter to clean it as you describe?

Eamonnator · 07-08-2015 9:50pm

Muckers wrote: »

Mech and cables shouldn't be an issue dirt wise. Mech is very clean and inner and outer gear cables are new.
I forgot to say that I can push the mech inwards no problem when the cable is removed while turning the pedals.
Will I need to remove the shifter to clean it as you describe?

Not, if you don't mind getting WD40 or whatever on your bar tape.

Harrybelafonte · 07-08-2015 9:53pm

How is the front mech supposed to change. When moving to smaller ring I have to click twice and the lever and it's more of a jarring change than smooth. I've just had it in two shops and nothing has changed?

Eamonnator · 07-08-2015 9:57pm

Harrybelafonte wrote: »

How is the front mech supposed to change. When moving to smaller ring I have to click twice and the lever and it's more of a jarring change than smooth. I've just had it in two shops and nothing has changed?

I've just got used to it.

Muckers · 07-08-2015 10:00pm

Your having to click twice because there is a trimming function when on the big ring only. This allows for a minute movement of the mech to avoid chainrub if necessary. I've never found Force to be particularly smooth and quiet. I have Red on my other road bike and there is no comparison imo

ashleey · 07-08-2015 10:33pm

Try the 'b' screw.

The top jockey wheel gets really close to the innermost sprocket when changing. You need to allow enough of a gap for the chain thickness to allow it to jump sprockets.

Makes a sort of grinding noise as you change up if the clearance is too small.

Harrybelafonte · 08-08-2015 6:07am

Thanks for replies guys. Did OP get his issue sorted?

ford2600 · 08-08-2015 6:19am

OP if you have external cabling set bike up on stay and see if you can move from second largest to largest cog by pulling cable.

If you can and keep it there then looks like shifter problem; you can also eye B screw adjustment when doing this and it'll confirm limit screw position.

Also might be no harm to check that hanger is ok and that screws have not loosened.

3102derek · 08-08-2015 6:28am

Make sure you follow the correct installation procedure.

Shift the leaver the lowest setting, then feed the cable, make sure it's pulled tight and clamp it in place.

I had a similar problem last week when I installed new shifters. It won't shift up because there wasn't enough tension on the cable, caused by the shifter been in the incorrect gear to start.

Muckers · 08-08-2015 4:31pm

onthefringe wrote: »

are you sure the mechanism in the shifter is not slipping under load?
hard to replicate it with the cable removed

Spot on. The issue is a shifter problem. Not shifting up under load. I took off the shifter and cleaned it fully, but the mechanism inside seems to have worn some, therefore slipping under load. Not a surprise I suppose as it's 5 years old and who knows how many thousands of up and down shifts it's done during that time.

Not a cheap fix either. €165 plus postage from Germany is the best I have seen yet. Thanks a lot to all you guys for the help and advice.

onthefringe · 08-08-2015 5:14pm

sorry to hear that..
very common problem with right hand levers on sram due to the double movement of every shift
what ever you do - dont buy second hand....maybe buy an apex shifter and swap the blade?

Muckers · 08-08-2015 8:08pm

onthefringe wrote: »

sorry to hear that..
very common problem with right hand levers on sram due to the double movement of every shift
what ever you do - dont buy second hand....maybe buy an apex shifter and swap the blade?

Cheers. I would never buy second hand. That's interesting what you said about Apex. Will it work just as well, and when you say swap the blade, do you mean removing both the brake and shifter levers and re fitting the Force ones onto the Apex shifter. If so, is this easy enough to do?

onthefringe · 08-08-2015 9:26pm

Muckers wrote: »

Cheers. I would never buy second hand. That's interesting what you said about Apex. Will it work just as well, and when you say swap the blade, do you mean removing both the brake and shifter levers and re fitting the Force ones onto the Apex shifter. If so, is this easy enough to do?

much like campag the "finger blades" on sram levers are replaceable..
my suggestion is buy apex....much cheaper...and change the blades from your force over to them so as to ascetically at least have a full force groupo but new shifter internals..

Sram force rear mech issue

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