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  • rear mech issues
  • Premier Icon sadexpunk
    Full Member

    not going so smoothly this bike build up, i seem to have forgotten how to set and use gears 😀

    just plopped the sram XO rear mech back on, its the same frame, same wheel, same cassette, same chain as before, yet the chains struggling to stay on the smallest cog and keeps trying to climb onto second cog. the mechs twitching away too.

    ive looked at the little adjustment screw and its fully off the contact, so the mech is as far over as it can i think. i also havent connected the cable to it yet just to prove that its not cable tension keeping it from coming fully over.

    the only other thing i can think of is the b-tension screw but im not sure what does. i think it sets gap between chain/mech and cog doesnt it? if anything its a little close, the cogs almost touching the chain, would this cause an issue?

    hopefully youtube linky below.
    rear mech youtube linky

    thanks

    Premier Icon whitestone
    Free Member

    Have you knocked the mech hanger? Check its alignment first.

    Also, are you looking at the correct limit adjustment screw?

    Premier Icon carlos
    Full Member

    Add 1/2 turn of B screw to move mech away from cogs
    Bent/misaligned hanger
    Incorrect adjustment of limit screws (are you sure the one not touching is the lower limit screw?)
    Is the stop tab in tbe right place and the hanger installed correctly

    Premier Icon sadexpunk
    Full Member

    Have you knocked the mech hanger? Check its alignment first.

    Also, are you looking at the correct limit adjustment screw?

    it all looks aligned when i look from the back, it doesnt look like it should be trying to climb. dont think the hangers been knocked. i wondered if the gap between mech and cog (b screw) could make any difference? do you think this is too close?

    also the lower jockey wheel is ‘spiked’, dont know if it should be or if its worn?

    yes im sure its the right screw. furthest away from the frame, it also has an H by it.

    thanks

    EDIT:

    Add 1/2 turn of B screw to move mech away from cogs

    thatll be my next move tomorrow, thanks.

    Premier Icon PJay
    Free Member

    If you’ve loosened off the H limit screw after attaching the cable, it could be now be the cable that’s limiting the outward movement of the mech.

    Premier Icon sadexpunk
    Full Member

    If you’ve loosened off the H limit screw after attaching the cable, it could be now be the cable that’s limiting the outward movement of the mech.

    i havent attached the cable, just to prove this point.

    thanks

    Premier Icon PJay
    Free Member

    i havent attached the cable, just to prove this point.

    thanks

    Sorry, I completely missed that the first time around!

    Premier Icon carlos
    Full Member

    Yes. In my opinion that gap between jockey and cassette is to close

    Bottom jockeyvwheel doesnt look worn to me, it looks forked

    Running gear could do with a good clean top

    Premier Icon sadexpunk
    Full Member

    Yes. In my opinion that gap between jockey and cassette is to close

    Bottom jockeyvwheel doesnt look worn to me, it looks forked

    Running gear could do with a good clean top

    cheers, ill have a play with the b-screw tomorrow.

    any idea which replacement jockey wheel id need? are they all the same or will i need to search for a ‘sram XO lower jockey wheel’?

    running gear looks dirty, and i spose it is, but i think it probably looks worse than it is. the chains just come out of a putoline bath, which whilst it doesnt clean it per se, i think it waxes/lubes the important bits?

    thanks

    Premier Icon sadexpunk
    Full Member

    well i screwed the b-screw in half a turn, no difference. looked from the back and altho it seems to be trying to skip and jump onto the 2nd cog, it really doesnt look like its the line thats causing this, the chain is just skipping.

    further investigation on the lower jockey wheel does indeed look like its borked. ive taken it off now.

    so, before i mess with anything else, ill get a new jockey wheel set and see how it goes.

    any idea which replacement jockey wheel id need? are they all the same or will i need to search for a ‘sram XO lower jockey wheel’?

    bump on this please?

    thanks

    Premier Icon joebristol
    Full Member

    I’d firstly borrow the tool you need to check the hanger isn’t bent – I had a brand new frame where it wasn’t aligned and I couldn’t get brand new gears to work until straightened.

    How worn is the cassette / chain / chainring? It looks tired – but maybe the dirt isn’t helping.

    Also – aren’t you meant to fully degrease / clean a chain before putting it in putaline?

    Premier Icon sadexpunk
    Full Member

    ill ask around a few mates see if anyone has one, dont think ive ever seen one tho so not holding out much hope.

    ill still need a new jockey wheel anyway, so nothing lost by getting sorted there and trying again if i cant get hold of a ‘hanger checker’.

    thanks

    Premier Icon sillyoldman
    Full Member

    Chain looks very worn which would potentially explain the nick of your jockey wheels.

    Premier Icon sadexpunk
    Full Member

    borrowing a chain-wear checker next week, but out of interest, how can you tell if a chains worn just by looking at it? just looks like a dirty chain to me 😀

    i havent actually ridden the bike yet since buying and repainting frame, so cant vouch for the mech/chain/cassette, but i spose it cant harm to get a new 9 speed chain anyway. its got a new front ring, itll have new jockey wheels, ill get a new chain too, i wont change the cassette yet tho as i want to prove 1×9 with it.

    hopefully this will sort the issue and negate the need to check the hanger alignment.

    thanks

    Premier Icon sillyoldman
    Full Member

    Chain pins don’t look centred between the teeth, and sprockets – esp the smaller ones, look worn.

    Premier Icon whitestone
    Free Member

    If you’ve a straight ruler (steel preferably) then just measure out twelve full links – they should come to 12″

    Worn chains are more likely to skip in the smaller cogs as there’s fewer teeth to engage.

    Premier Icon granny_ring
    Full Member

    Mate, check the gear hanger. They never look out but 3 out of 4 of mine were.

    Premier Icon sadexpunk
    Full Member

    Chain pins don’t look centred between the teeth, and sprockets – esp the smaller ones, look worn.

    If you’ve a straight ruler (steel preferably) then just measure out twelve full links – they should come to 12″

    ah gotcha, thanks.

    Mate, check the gear hanger. They never look out but 3 out of 4 of mine were.

    had a look at tool prices and they scared me, so i assume best bet is to take it into a shop and ask them to check it?
    out of interest, how easy is it to bend back a steel frame if it is indeed needed? its just had a repaint so dont want to start chipping/cracking the paintwork.
    hopefully itll just be the jockey wheels and chain thats causing the skipping…..

    Premier Icon sillyoldman
    Full Member

    Chains do stretch, but by very little – the rollers on the pins wear though, which means that the effective pin to pin distance increases, giving the same effect as stretch, so a chain measuring tool is more use in gauging wear than a ruler.

    Premier Icon gkeeffe
    Full Member

    A quick way to guess how worn a chain is is to twist it and compare that to a newer one. Worn chains twist loads more that’s why the shifting goes awry.

    Premier Icon Scienceofficer
    Free Member

    The only thing you can tell for sure from that picture is that the b tension is insufficient and that jockey wheel is ****.

    The small sprockets are out of focus and the angle of the photo doesn’t let you see the relative position of the pins between the teeth with any clarity.

    You can maybe draw some conclusions like that KCNC jockey isn’t original -if the rest of the running gear is it’s almost certain to be worn if it’s lived long enough to go through two sets of jockey wheels.

    Premier Icon DaveP
    Full Member

    Every single one of our bikes had a bent hanger. I would (now) check them first always.

    Premier Icon sadexpunk
    Full Member

    update time. mate came round with his chain checker and confirmed that out of the 2 settings, ‘fked’ or ‘fked fked’ it was indeed the latter option.

    new kmc chain, 2 new superstar jockey wheels, mates also given me a better cassette than i had on (hes a good lad isnt he) and the result is……… its still climbing on the smallest cog. probably even worse than before.

    so, we’re now left with either a bent mech, or bent hanger which is your favoured option so far i think 🙂
    mate says hes going to attempt to make an alignment tool at work so we can check it (told you he was a good lad didnt i).

    the videos ive watched on youtube so far show sacrificial hangers, mines a steel mk1 soul and its part of the frame. there shouldnt be any problem bending it should there? no chance of it snapping? is it ok to bend a steel hanger?

    also i wondered about the paint on the hanger. ive just had it resprayed and so its obviously got a new coat on it. thats fine isnt it? doesnt need to be a ‘faced’ finish?

    thanks

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