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Useful information:

  • The bike is currently on the smallest sprocket and smallest chainring (smallest rings by pedals and rear wheels incase my terminology is wrong).
  • Rear wheel is currently not centered.
  • I've been looking at the bike upside-down
  • The chain is the correct length, tension, as far as I can tell, is as it should be, and all other parts are correct
  • The derailleur was properly adjusted before the wheel was removed and then reinstalled, and neither the cable nor the screws (H,L, or the other one) have been touched.

So right now the upper pulley is very close to cassette (specifically the smallest cog on the cassette, where the chain also is right now). It is almost close enough for the pulley (well the teeth of the pulley I guess) to be engaging the same length of chain that is on the cassette.

Is this incorrect? Also, out of curiosity, would there be an issue if the pulley and the cassette were engaging the same length of chain?

The current position of the derailleur looks a bit like in the picture below, except with the upper pulley a little closer to the small cog on the cassette.

http://cdn.mos.bikeradar.imdserve.com/images/news/2012/10/30/1351601204145-dusw1th1s7gr-960-540.jpg (Picture taken from http://cdn.mos.bikeradar.imdserve.com/images/news/2012/10/30/1351601204145-dusw1th1s7gr-960-540.jpg)

Thanks.

Note: I'm not riding the bike as it currently is (nor have I yet tried). I've been working on it (and am almost done, just have a bit more to do like center the wheel and lubricate some parts), but I noticed this and decided to ask, in case I did something wrong or need to adjust the derailleur.

  • I would take it to a really good LBS. That dérailleur is probably worth around $300, the mind boggles at what the bike is worth. Getting it wrong will cost a lot more than a 1/2 hour labour charge. – mattnz Aug 26 '16 at 1:39
  • I don't see what you're talking about -- there looks to be about 3/4 inch between the small sprocket and the idler pulley. And it's normal for them to be fairly close together. (I guess I'm wondering why the wheel is not centered, since that's pretty much the first thing you do after getting the wheel in the slots and the chain threaded.) – Daniel R Hicks Aug 26 '16 at 1:49
  • The bike pictured is not my bike. And I agree that about a 3/4 inch space is okay. What I am wondering is whether a space of about 1/4 of an inch between the small sprocket and idler pulley is okay (I didn't think to actually measure the distance, but I will do so when I get a chance) (and the wheel is not centered because I am in no rush and didn't feel like doing it at the time. I happened to notice the small gap between small sprocket and idler puller on my bike (again, not the one in the picture) and was curious about it). And thank you for your responses – user106860 Aug 26 '16 at 1:59
  • This looks like a SRAM x1 gearing where there's only one chainring and a wide-range cassette (~11-42). So the set-up is certainly according to factory specifications. – Carel Aug 26 '16 at 7:33
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Several things coming to mind when I read this.

a) If the wheel is not centred, its not sitting in the drops correctly. If its not sitting in the drop-outs correctly, the axle to derailleur mount distance and the angles of the derailleur to cassette are off. There is little point looking at derailleur adjustments unless the wheel is centred.

b) Smallest smallest is cross chained. Performance of derailleur in this state is relatively unimportant

c) The derailleur was properly adjusted before the wheel was removed.... The thing that affects the clearance of the jockey wheel is the B screw - was this changed?

The first thing to do is put the wheel on straight, remove the cross loading by putting the dérailleur onto the largest rear cog, and if needed, adjust the B Screw.

  • Yep. And never turn the bike upside down again! – andy256 Aug 26 '16 at 10:14
  • ^Unless you're doing back flips off sweet jumps – Nate W Aug 26 '16 at 16:02

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