Hi,
I'm flummoxed with my bike.
I am getting chainsuck when pedaling backwards on my bike. Situations such as positioning the pedals at traffic lights and junctions, or getting my footwork right in very slow sections.
Interestingly, this only happens when I have weight on my bike - ie. me. It does not happen at all when the bike is in the workstand or leaning against a wall, only when I am sat or stood on it. I weigh 69kg.
I have rebuilt the rear mech, cleaned the chain and chainrings. The mechs are working perfectly.
The BB does not appear to have any play in it.
I can't see any damage on the frame to indicate that it is not true.
It is a mix of 8 and 9 speed, but has been running fine for months, this problem is only recent and getting worse. Sprocket is fairly new 8 speed (XT), chain is fairly new 8 speed, chainrings are fairly new 9 speed (SLX). Rear mech is about 14 years old (LX) and front mech is fairly new (SLX). Pretty sure the chain is of the correct length. My first thought would have been the mix of 8 and 9 speed if it wasn't for the fact it has been running fine since I built it.
Frame is a 14" Inbred.
Help! Any thoughts?
dan
broken axle letting the cassette move out of line under your weight?
or broken frame even....
not a spec issue, sounds like freehub problems
how old is the hub?
Is the chain actually sticking to the chainring, or just drooping a lot when backpedalling?
I've been over all the welds on the bike, everything looks good there.
Axle is okay, I had that out when I was regreasing the bearings in the hub.
Rear hub is less than a year old and the freehub feels like it is functioning correctly, but I haven't taken it apart yet, so will have a look at that.
Cheers,
dan
Is the return spring in the rear mech going (the one that pulls/rotates the arm back towards the body of the mech)? Had a similar thing happen with an old XT mech, and this appeared to be the cause.
Just checked and the return spring is offering considerably less force than a modern XT rear mech, so maybe that is the cause.
No problems with the jockeys then- the cage is all square? If top and bottom are slightly out of alignment, that can cause stiction.
Just checked and the return spring is offering considerably less force than a modern XT rear mech, so maybe that is the cause.
Sounds like the puppy then - if the spring is weak then the chain will not be under full tension when back pedaling, but pedaling forwards will take up the slack. Hence your problem.
when I was regreasing the bearings in the hub
recently?
maybe a bit too much, or a bit too thick?
or else a bent hanger/misaligned mech?
+1 for freehub, I had this problem on a hope pro II hub and it turned out to be a siezed bearing race in the free hub.
Try pedaling forwards 😆
Yep, jockey wheels are in good condition and are spinning freely. Cage looks square to me.
I've just been watching what happens more carefully - when I pedal backwards the bottom of the rear mech is being pulled forwards and the chain is not feeding through, so is rolling down with the rear of the chainring.
Cheers for the all the suggestions so far, have a couple of things to investigate now.
dan
fivespot - Member
Try pedaling forwards
That's so 2009 🙂
dan
return spring +1... amd the mech hanger and cage has to be straight or the problem will persist for sure...
Cheers for all the help.
Pretty sure now that it is the rear mech - now I have taken it off the bike I see that it has quite a lot of play in the pivots as well as the spring not pulling with as much force as my other mech.
I'm a little confused as to why it is only an issue when I am on the bike, though.
I've converted it to singlespeed for the time being and is running backwards fine.
thanks,
dan