chain rattle and bumpy ride

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aljohn
Posts: 59
Joined: 7 Sep 2012, 9:39pm

chain rattle and bumpy ride

Postby aljohn » 23 Jun 2017, 3:46pm

Building my Dolan involved buying,mainly, good used components. So I ,ahem, sometimes got carried away with a bargain of the decade or so.
I've fitted Shimano Ultegra brakes, shifters and mechs, short cage rear mech. 11/28 cassette, new, and 34/50 Stronglight chainset, also new. The gears work perfectly and I'm pleased with them. I adjusted the new KMC chain so there is no spare chain to flap about on the big/big and the chain climbs easily on to the largest sprocket. However, when in small/small on a bumpy road there is a lot of chain rattle - quelle surprise! To be quite honest it is no big deal, but I have tried fiddling with the b screw and that does not seem to make any difference. I wondered if the rear mech, if new, would have kept the chain a little more taut, or am I trying to interfere with the law of physics and should just shut up and keep riding?
The bumpy ride I attribute to a pair of Specialised wheels - 20 radial spokes at the front and the rear has 12 radial spokes on the non drive side and 12 tangential spokes on the drive side. Fitted with Vittorio training tyres, 23c. I've only done 657 miles and the centre tread has virtually lost the tread pattern....
Sorry for the long post, if you've read this far feel free to criticise my choice of components,my thinking, whatever.
As I said, I'm happy with my build and will continue to use it, but I'm curious what others think. Thanks

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foxyrider
Posts: 5225
Joined: 29 Aug 2011, 10:25am
Location: Sheffield, South Yorkshire

Re: chain rattle and bumpy ride

Postby foxyrider » 23 Jun 2017, 4:49pm

Sounds like your chain is maybe a couple of links too long. Is there any tension when in s/s? How are the jockeys aligned in b/b?

Not quite sure why you think a 'bumpy ride' is related to the spoke count? I don't get a bumpy ride with fewer spokes than that - are your wheels actually round? Not being facetious, but it's possible for wheels to look round but actually not be. Are the tyres seated properly? This can also give a bumpy ride.

Fast wearing tyres - Wang some Gatorskins on and you should get @ 2k out of them. High wear rates can have many causes from tyre pressure to rubber compounds.
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!

Brucey
Posts: 42167
Joined: 4 Jan 2012, 6:25pm

Re: chain rattle and bumpy ride

Postby Brucey » 23 Jun 2017, 6:26pm

fatter tyres/lower pressures might make the ride a bit better, but if the chain rattles, is the top run hitting the chainstay? Things that will make this more likely include;

- low chain tension
- fat chainstays
- elevated chainstays
- small sprockets
- small chainrings
- any stiffness in the lower derailleur pivot
- not pedalling hard enough.... :wink:

A simple tweak is to add a protective strip of some kind to the chainstay; if you make it in the right material (why not a strip of old inner tube?), it will at least make life a bit quieter even if it is still touching.

The other place you can get a noise running small-small is if the chain is hitting the side of the big chainring on the slack run; this is more or less an occupational hazard with modern derailleur systems...

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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Tigerbiten
Posts: 2142
Joined: 29 Jun 2009, 6:49am

Re: chain rattle and bumpy ride

Postby Tigerbiten » 23 Jun 2017, 8:20pm

Brucey wrote:The other place you can get a noise running small-small is if the chain is hitting the side of the big chainring on the slack run; this is more or less an occupational hazard with modern derailleur systems...

I had that with my original setup on my 53/38 double setup.
I had to add 1 mm chainring spacer washers to cure it.
My new 54 tooth chainring has no ramps or pins, so I've add an extra 2 mm spacer to help the chainring upshift.

Samuel D
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Joined: 8 Mar 2015, 11:05pm
Location: Paris
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Re: chain rattle and bumpy ride

Postby Samuel D » 23 Jun 2017, 10:13pm

My chain rubs against the outer chainring in small-small and the adjacent rear gear (small-smallish). This is not a problem, since I never deliberately use those gears. It is more efficient, smoother, and less wearing on the drivetrain to shift to the large chainring and an appropriate rear sprocket instead.

gxaustin
Posts: 624
Joined: 23 Sep 2015, 12:07pm

Re: chain rattle and bumpy ride

Postby gxaustin » 23 Jun 2017, 10:18pm

I had this very problem - and found that the mech pivot was partially seized. I had to dismantle it and clean it up/regrease. Cured.

Roadster
Posts: 443
Joined: 26 Jul 2016, 2:12pm
Location: E.Lancs/W.Yorks border

Re: chain rattle and bumpy ride

Postby Roadster » 23 Jun 2017, 11:03pm

When I were a lad, we were told we shouldn't use either big/big or small/small because of the excessive chain deflection, so we only got eight permissible speeds from our 10-speed derailleur systems...

aljohn
Posts: 59
Joined: 7 Sep 2012, 9:39pm

Re: chain rattle and bumpy ride

Postby aljohn » 24 Jun 2017, 6:30pm

Thanks for the replies. Just to clarify, I very rarely use big/big, but it's there to use if I want it. Also the jockey wheels are pretty well stretched out in that gear, so I haven't got any chain links to take out. The chain doesn't touch the chainstay at all. I agree that using the big ring and appropriate sprocket does quieten things down considerably, so I'll have to make myself stick to that....I do love that little ring, though, sigh. And I think that Brucey was very rude to suggest I pedal harder, I feel quite hurt :( I know he's right, but everyone else knows now. With the disappearance of tyre tread so quickly it looks like a pair of 25c replacements will be appearing soon. I wasn't concerned about the thread count, I just wondered if the spokes being radial would give a harder ride than the tangential spokes I've always had before?

gregoryoftours
Posts: 1410
Joined: 22 May 2011, 7:14pm

Re: chain rattle and bumpy ride

Postby gregoryoftours » 28 Jun 2017, 9:16pm

Maybe a medium cage rear mech would be more suitable than a short cage with that range of gears, would take up the chain slack better and it wouldn't be so baggy in it's loosest state. In any case you shouldn't be riding in small to small.