Going from 2x to 1x

snoopsmydogg

First off, apologies if this has been asked before.

I recently changed my deore 2x10 groupset to a 32t superstar n/w chainring and xt casette with expander ring but I seem to be having an issue with the chain slipping when its on the expander ring and under load. Everything is either new or as new so I don't think it's a wear issue but when in the expander ring the chain does look a little bit off.

Is it worth taking the drive side spacer out of the bottom bracket and moving it across or is there anything else that others have tried?

All gears change smoothly up and down

dgmoose

The way you describe your problem is a bit vague.

1) What is the tooth count on the expander cog?
2) In which position is the 32T chainring fitted on the crank spider?
3) Chain slip, how? Does it slip over the cogs with a machine gun sound? Does it slip as in not driving the rear wheel? Slip as in back pedalling?
4) Extreme chainline may well be the cause of the problem but we need more information. For instance, if the chainring and biggest cog exceed a certain size (tooth count) then that can cause an extreme chainline on a medium cage rear derailleur (RD) with the result that the chain will slip off to one side of the lower pulley wheel on the RD.

snoopsmydogg

Sorry ill try to fill in the blanks.

Expander cog is 40t and I'm using a deore shadow plus clutch mech if that makes a difference.
The 32t chainring is fixed on the inside of the crank. The crank was originally a double so it was the only place I could fit it.
The chain slip just sounds like it's not connecting properly. it only does it under load and isn't continuous.
The chain line was just an idea. Like I said everything is new and shifting well.

Cheers

dgmoose

If the 40T cog expander is brand specific then make sure a Shimano compatible is fitted to a Shimano cassette, a SRAM compatible to a SRAM cassette etc.

If the chain is directional then make sure it is running in the correct direction.

In the biggest cog, you get high torque and low speed which means that there is the possibility that the 40T cog may cut into the freehub body (especially if it is an aluminium freehub) or it may wear down the 40T cog notched interface so that it could be rotated forwards and backwards slightly without the hub moving. As a result, your pedal stroke will experience the occasional slip (similar to a sticky hub pawl) especially when there is a change in cadence.

Sometimes, you can also observe a similar slip where the teeth on the cassette and on the upper pulley wheel don't quite mesh together for one or two links of the chain. This condition happens if the chain is stretched or has a stiff link or the pulley wheel is worn down to a smaller size.

So, inspect the movement of the chain at the location of the RD upper pulley wheel then remove, and inspect the 40T cog and the freehub for damage.

The Rookie

Brand specific only relates to shifting, not engagement once in gear!
Ditto directional chains (which aren't directional but again handed for shifting).
With no force to rotate the expander backwards that clearly won't happen so it can't then slip, most have the spacer built in so are a wide base anyway.

I would agree with checking for a stiff link - where the tight radius of the jockey wheel can cause an issue as it climbs onto the biggest sprocket, I have seen a stiff link result in one chain roller being spaced off the sprocket completely and the pins either side occupying adjacent valleys on the sprocket.

Is it possible you are getting a ghost shift briefly onto the next smaller sprocket? Check the L stop and indexing.

FishFish

Check everything that has been suggested but your comment that the chain 'looks a bit off' I guess refers to the chainline which you can of course address by putting the (one of the) drive side spacers on the other side of the bb......I assume that you did not put a chain device up front when you changed to 1x - if this was on the bb then of course it would shift the chain line detrimentally.

Good luck.

snoopsmydogg

Thanks for the replies. It gives me a few things to try and hopefully I'll get it sorted.

Fishfish you are right about the chain line looking off, the bottom bracket only has one spacer but it is on the drive side as I didn't change anything other than fitting the narrow wide chainring ring. I fitted an iscg 05 e13 chain device at the same time but it only guides the chain under the crank to the derailleur (if that makes sense)

cycleclinic

Sunrace do good 10 speed 11 to 40t cassettes get one of these rather than faffing with expander cogs.

Is the slip, the chain trying to come off the cogs or a slip when yoh have worn cogs. Or is it the hai not eunning smoothly over the large cog because the top jockey wheel is too close.

B tension screw adjustmwnt maybe needed

cooldad

thecycleclinic wrote:

Sunrace do good 10 speed 11 to 40t cassettes get one of these rather than faffing with expander cogs.

Is the slip, the chain trying to come off the cogs or a slip when yoh have worn cogs. Or is it the hai not eunning smoothly over the large cog because the top jockey wheel is too close.

B tension screw adjustmwnt maybe needed

Drunk?

FishFish

cooldad wrote:

thecycleclinic wrote:

Sunrace do good 10 speed 11 to 40t cassettes get one of these rather than faffing with expander cogs.

Is the slip, the chain trying to come off the cogs or a slip when yoh have worn cogs. Or is it the hai not eunning smoothly over the large cog because the top jockey wheel is too close.

B tension screw adjustmwnt maybe needed

Drunk?

I used to be most of the time in fact. I highly recommend it!

snoopsmydogg

So a bit of an update.

I've removed the drive side spacer and put it on the other side of the bb and now the chain line looks a lot better when in the expander ring.

The chain is new and I haven't managed to find any stiff links.

I've tried adjusting the l screw and cable tension etc. The only thing I forgot to try was there b screw adjustment but it shifts in and out of gear fine so not sure that is the issue but I'll give it a try next time.

There has been a big improvement but when pedalling hard it still sounds like it's going to slip.

The Rookie

Adjust the b-screw for goodness sake.

Not sure how a chain can sound likes its going to slip?

snoopsmydogg

Hard to explain but when pedalling hard the chain will make a sound like it is slipping/jumping intermittently but i don't feel anything through the pedals.

The Rookie

Could be a stiff link or chain suck?

EDIT: SS's NW rings are known to be a bit 'rough' when brand new, they quieten down after a few rides, make sure the chain is lubed properly as well. NW rings are inherently noisier due to the tighter clearances between the teeth and inside of the chain.

JGTR

Just to confirm you have re-indexed you rear derailleur, setting H & L stops, adjusted the B screw and then tensioned the cable correctly??

Could it just not be a noisy cog? What make is it?

Giantmatt75

Sounds like the indexing is out , get that checked first or your fighting a loseing battle

snoopsmydogg

Giantmatt75 wrote:

Sounds like the indexing is out , get that checked first or your fighting a loseing battle

Would indexing not affect all gears?

Shifting is fine up and down, it's only when under load in the expander ring that's the issue

cooldad

The Rookie wrote:

Adjust the b-screw for goodness sake.

Not sure how a chain can sound likes its going to slip?

JGTR

I think what everyone is saying is have you actually set up your gears properly or do you just keep staring at them?