new derailleur bigger jockey wheels

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jawaka
Posts: 538
Joined: 6 Dec 2007, 2:46pm

new derailleur bigger jockey wheels

Postby jawaka » 15 Oct 2018, 1:12pm

I bought a new 7 speed derailleur cage as I thought the old was seized but it's my winter bike and the cable had seized in the cable outer and the exixting derailleur seems ok. I might just keep the new unit for future use, but I notice that the jockey wheels are quite a bit bigger. I didn't have the old one with me when I bought it, but I am wondering if it is the wrong size. Unless it is wrong I don't think I can send it back as the explanation sheet is finger greasy and the box obviously opened. The bike is the winter bike and it is a 1980s Dawes Horizon tourer (in purple and not very thievable!)

Have jockey wheels changed size for newer derailleurs?

Brucey
Posts: 42881
Joined: 4 Jan 2012, 6:25pm

Re: new derailleur bigger jockey wheels

Postby Brucey » 15 Oct 2018, 1:22pm

some models have large, others small. Large jockey pulleys run easier/quieter and also increase the capacity of the mech slightly in some respects. However if the bushings are cheaply made (as they often are) then the pulley has a shorter life than normal because it is unable to guide the chain as accurately for any given amount of wear. Swings and roundabouts really.

Most half-decent shimano mechs made in the last 20 years have 11T pulleys. Some mechs (for some reason mainly very cheap or very expensive ones) have much larger ones than that.

cheers
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Sweep
Posts: 6898
Joined: 20 Oct 2011, 4:57pm
Location: London

Re: new derailleur bigger jockey wheels

Postby Sweep » 24 Apr 2019, 1:04pm

ah the wonders of a forum search (and the great source of knowledge this place is) - found this after musing on a current bike build.

8 speed tourer.

Two mechs in the spares box have oversize jockeys - think I'll fit one and keep the other as a spare for possible early failure.

Save the 11T things (easier to keep running with spares) for the "classier" builds.

Yes the dichotomy on price is curious brucey.

Have tended to associate them with possibly gimicky cheaper mechs.

But a fast bit of internet search reveals that some TdF folks have been using rear mechs with oversize jockey wheels.

Though probably not Altus/Alivio.
Sweep

scottg
Posts: 889
Joined: 10 Jan 2008, 8:44pm
Location: Highland Heights Kentucky,, USA

Re: new derailleur bigger jockey wheels

Postby scottg » 24 Apr 2019, 1:39pm

Grant likes the Altus.....
Note the short cage is nice for small wheel bikes.

https://www.rivbike.com/collections/der ... m310-17167
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