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Why the chain goes tight.

spikeywan

New Member
I just worked out why the chain was too tight on MeNewBlade.

I adjusted it myself and it was right, but when I got home, it was too tight again. So I re-did it. After doing it for the second time, and tightening everything back up, I did one last check, and it was too tight again!

This is why:

The axle bolt has a round head with 2 flats. This sits in a carrier, which is like a box with no lid.

When you undo the adjuster bolts, it pushes the carrier (and hence the back wheel) backwards. If you tighten the adjusters, you have to move the carrier forwards to take up the slack.

Once you have the rear wheel in the correct position, you tighten the axle bolt. What happens when you do this is that the bolt head rotates slightly, so that the point on the edge of the flat touches the edge of the carrier. Continued tightening of the nut uses this point as a lever and it forces the axle bolt backwards slightly, tightening the chain.

This is because the bolt head is not a tight fit in the carrier.

Does anyone know if it's a tight fit when new? If so, then my best course of action may be to get a new carrier.

I ask, because I bet that lots of tightening or over-tightening of the axle bolt is bound to flare the carrier slightly and possibly stretch the hole for the bolt. This will only make the situation worse. It may also mean that the rear wheel isn't quite straight, because the carrier on the chain side is slightly longer than the one on the brake side.

Unfortunately, I don't have a stand yet, so I can't take the back wheel off to see if I can tighten the fit of the carrier onto the bolt head. I also want to compare the 2 carriers to see of they are the same length.

If this is a common issue, and the carriers aren't that tight when new, then it could easily be cured by putting something between the carrier face and the flat on the bolt head to stop any rotation.
 

KevCBR600

God is busy, can I help?
Just smack the rear wheel into place and tighten the nut up. Can't say I have ever had an issue with it.

Have a looky CLICKY
 
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