rough drivetrain issues

mightyi

I've just replaced virtually the whole groupset on by old cube attention, but i'm currently having some problems with rough gearing. i've fitted a Deore HG50 9 speed cassette (11-34 instead of previous 11-32), an HG53 chain (cut to the correct length), M442 crankset (plan to upgrade to a Deore set when i get the BB faced off and a hollowtech BB in there to get rid of the tapered BB), with a Deore shadow rear mech and Deore front mech. I've got a new mech hangar on order as the one on it is a bit battered, but I've spent a few hours making sure it is perfectly straight.

The problem ive got is no matter how much a tweak the mech/cables/hangar etc, i cannot get the gear to run smoothly. if i look closely I can see the chain seems too "tight" for the cassette sprockets?? I replaced the mechs after finding this problem at the weekend, but although it's a lot better without the worn mechs, it still sounds like the chain is struggling to mesh with the cassette. As a test, i've swapped the cassette for the old one and the problem goes away! i've checked there are no snagging problems with the jockey wheels and new cassette and there's nothing wrong.

Can anyone suggest anything or do i just send the cassette back as faulty? seems strange an old cassette works fine with a new chainring and chain etc, but not a new one?

The Rookie

I don't understand your issue.....

How did you size the chain?

Look from behind, you should be able to see the upper (and lower) jockey wheels aligned with each cassette gear in turn, always a good indication it's aligned right.

Photo from behind would help.

I suspect the mech hanger.

Huckfinn

It does sound that the chain is too tight. What method did you use to measure the chain length? Does it run rough through the whole range or just certain ratios? A pic might help too

mightyi

Thanks for the replies guys - I've got the old cassette on at the moment so will swap them over later and take a picture.

With regards to the chain, I did it according to the Park Tools site - i.e. big ring to large sprocket, plus 1 complete link. looking at the rear mech on this setting, the chain doesn't look too tight at all. At first i thought it might be the old reach mech not liking the change from a 32t to 34t top sprocket on the back, as it struggled to give sufficient clearance between cassette and jockey wheel....or it might be the BBB jockey wheels i fitted; but neither of those seem to be the issue as the new Deore mech (with shimano jockey wheels) is still doing it.

I also spent quite a long time getting the rear hangar parallel to the rear wheel (to be fair it was badly mashed up!) - new one is on it's way fro BETD, but it looks ok - although saying that, the arm of the rear mech isn't quite parallel when on the largest sprocket, even though the hangar is?

WindyG

Sounds like you need to correctly index your gears and that the B angle screw needs to be set correctly for the new cassette try reading this guide http://www.bikeradar.com/gear/article/workshop-how-to-set-up-the-gears-on-your-bike-23582/

maringirl

B screw needs adjusting - gone from 32t to 34t

mightyi

Ok well there's something screwy going on here.....I've now replaced the rear mech hanger (it was stuffed), and also replaced the rear mech for a deore shadow one, and replaced the front mech, as well as the gear cable inner and outers with decent ss cables. gear change is a lot better (except when i've gone through mud when its bleedin awful lol) - but when riding, i keep getting an intermittent noise from the rear when pedalling that sounds like it's not quite in gear. I've now checked and re-checked a dozen times and i can't find a stiff link, the mech is lined up great and gearchange is snappy and immediate so no apparent problems there. i just don't get it! anyone got a clue?!

mightyi

any suggestions?

Its definitely not the B screw - checked there is sufficient gap between the top jockey wheel and the largest cog (approx 5mm), and rechecked the derailleur is set bang on - all spot on. only thing i can think of is play in the freehub? there was a very slight amount but wouldn't have thought it enough to cause rough drivetrain.

I've checked the chainline and it's running 50mm, is it maybe worth me reducing it to 47.5mm? it originally have a truvativ bottom bracket and crank (68mm/113mm), i've changed it to a shimano UN55 (113mm) and 442 crank; wondering if perhaps this might have something to do with it?

cooldad

Sounds like it's not indexed properly