At my wits end drive train help

DODGEYONE

Hi as i have put up the top i am at my wits end,the problem i have is ,on my boardman fs i have this drive train (frame bought then built by me)

specs

firex 3.3
slx back mech
hg 53 chain
xt rear cassette
deore shifters

the gears set up fine up and down perfect but when i go out on the bike and push hard the chain or something slips.
now i have tried new chain different wheel and cassette,redone cables but still no joy all seem the same,all thats left is maybe shifters but can they really cause so much of a problem ,any help will be most welcome thanks

nicklouse

poor cable routing or too short cables?


worn free wheel.

all the same speed kit?

DODGEYONE

ok cables were same as the ones that did come with the bike so maybe not ,how can i tell if the free wheel is worn.and yes all 9 speed.also i have tried another wheel and still slips.

cooldad

Were the parts new, could just be worn chain, cassette, chainrings.

DODGEYONE

ok yes the firex is new the chain is new the cassette is hardly used,only the shifters are old.can it be anything to do with this b screw on mech i have not moved it at all.

DODGEYONE

Hi just a an update the gears dont slip out of gear just a loud crunch from the drive train as i pedal.normaly in the bottom 3 gears under load

manofsteel

chain too short to allow for suspension travel?

DODGEYONE

hi i did think that but the chain length is spot on,even in lower front cogs it still crunches.

nicklouse

pics of the set up.

DODGEYONE

ok will post monday thanks

ilovedirt

So you have new cranks, are the chainrings new? Sounds like you're running something that's worn with something that isn't.

DODGEYONE

Yes cranks new chain new rear mech new cassette nearly new,only thing old is shifters.tried different wheel with different cassette and chain still slips,well not slipping just crunching,no idea whats causing it tried it all .hanger straight mech in line chain no tight links crank soilid chain rings new.i have built a couple of bike also fixed some but this has got me.

bails87

Something must be loose. Or rear mech isn't set up right.

Disconnect everything, and start again. Follow the manual and make sure B screw and cable length/routing is correct.

Or, put the back brake on, hold the bike still and put pressure through the pedals, you might see something move?

DODGEYONE

Hi had a good look at it today seems to be what i think is called chain suck maybe,the xt cassette is super narrow and the hg 53 seems to be bog standard so i think this my be the cause.
When i put on some old cogs at the back ie replaced the bottom three on the xt cassette no slips and no need for spacer.
So because of this i am going to get a cassette to go with the chain which one would be ok DEORE or slx?

cooldad

XT, SLX and Deore all have the same spacing, so it shouldn't make any difference.
Sure you don't have a 10 speed cassette.

ps that's got nothing to do with chainsuck.
http://www.diaryofamountainbiker.co.uk/chainsuck.php

DODGEYONE

This be ok http://www.jejamescycles.co.uk/shimano- ... 12683.html

DODGEYONE

Hi no its a 9 speed xt cassette but on my hub i need a spacer or the whole things loose.

xt hub on mavic rims

cooldad

Are you putting the spacer in the right place on the XT - spacing the cogs and not on the outside?

DODGEYONE

The spacer is at the back of the cogs,on the xt cassette it has built in spacers on the cogs

cooldad

And you have them all the right way round?
But something doesn't make sense - you say in one post the XT doesn't have a loose spacer, and in another you need a spacer or the cassette is loose?

DODGEYONE

Ok the xt cassette has to have a spacer at the back on my hub or it is loose,but when i put on the old bottom 3 cogs from my deroe cassette they are wider so no need for spacer at back

cooldad

I'm fairly sure the spacer spaces out the smaller cogs, not go at the back - why not put both cassettes next to each other and get the spacing the same.

DODGEYONE

Yes i know what you mean but the xt cassette dose not have separate spacers just a block of 6 then 3 rings with the spacer built in,i had to buy the spacer at back as it was to loose, as someone said its something to do with mavic wheels and xt cassette needing a spacer to fit.

junglist_matty

What Mavic wheels are you using?

I've run both XT 9 speed and XT 10 speed cassettes on my Mavic Crossmax ST's with no problems what-so-ever, no spacers required.

ride_whenever

Sounds like a dying freehub

cooldad

Pile them up like a kiddies stacking toy and make sure all the coogs line up.

njee20

Some Mavic hubs do indeed require a spacer, about 1.5mm at a guess, silver thing - but there's no reason at all for you to need it with an XT cassette and not Deore, so something must be amiss.

If changing some of sprockets solves the problem the issue must be with those, either they're worn, which is possible, or you've got something in the wrong place.

DODGEYONE

Ok my rims are mavic 721 on a xt hub,without the spacer its loose.
The xt cassette is smaller than my old deroe but they are both 9speed.
My chain is a hg53 which seems to wide and it slips on the bottom 3 gears badly,on inspection they are not worn.
My thinking is that the chain is wrong as its to wide and making grip on the big cogs due to the amount of teeth but when in smaller 3 slips as its to wide for the little thin teeth on the xt.
Also how do i tll if freehub is gone,it runs smooth but could it be slipping?

njee20

Right, you shouldn't need any spacer on an XT hub with any 9 speed cassette. Something is wrong.

The XT cassette has little black spacers that go between the individual cogs, but no others.

The HG53 chain is 9 speed, so that's not the issue, unless you have a 10 speed cassette.

cooldad

Point is the cassettes should be the same width, so somewhere a spacer is in the wrong place.
Stack them next to each other and make sure all the cogs line up on both cassettes, if not you have the spacing wrong.
If as you say, the chain seems too wide for the smaller cogs, this would indicate the spacing iss wrong as the chain is correct for the cassette.

junglist_matty

njee20 wrote:

Right, you shouldn't need any spacer on an XT hub with any 9 speed cassette. Something is wrong.

The XT cassette has little black spacers that go between the individual cogs, but no others.

The HG53 chain is 9 speed, so that's not the issue, unless you have a 10 speed cassette.

My 9speed XT cassette doesn't have spacers; its got a block of 6 cogs attached to a spider that slide onto the freehub first, then 3 individual cogs that slide on the freehub in order of size.


Check that you have put the 3 individual cogs on the right way around; the spacer is part of the cog itself (one side of the cog is thicker than the other).... If you have one of these on the wrong way around, the spacing will be wrong and cause you're problem.