1

The other day I had to replace tires on my bike.

Having recently switched to a belt drive + gear hub, I have looked at some on line tutorial on how to remove the rear wheel in such cases.

Problem is that the on line tutorial showed the case of a bike with only 1 tensioner while my bike has two, one on the right side and one on the left side, so once I mounted the wheel back and adjusted the tension of the belt (I used the app suggested by the belt manufacturer to measure the tension) I found that the movement was no longer fluid.

I suspect that I didn't properly balance the tension between the two side, but I have really no clue on how to do it.

How can I correctly adjust the tension of a belt drive with two tensioner?

  • By "two sides" you mean the top and bottom run of exposed belt, right? Not two separate belts on either side of the bike? I'd have thought the tension would be the same on top and bottom because the rear "cog" or front "chainring" would simply move to equalise the tension. Does the reinstalled wheel spin freely in the frame ? – Criggie Nov 14 at 6:48
  • 1
    @Criggie, I am referring to the bolt+nut assembly which is used to tension the belt. There are two, one on the right side and one on the left side. – L.Dutch - Reinstate Monica Nov 14 at 6:51
  • 2
    Is there something to tension on the non drive side? My guess would be that you adjust the tension on drive side and use non drive side adjustment to keep the wheel straight. Or just remove the non drive side tensioner and keep it as a spare for drive side. – ojs Nov 14 at 9:35
  • @ojs you are correct the left side (non drive side) tensioner is used to adjust the wheel to be straight/in line with frame. – Maarten Nov 19 at 5:59
0

To try and get the wheel perfectly straight you could try to fully loosen each nut on each tightener. Then put each nut back on its respective tensioner and whilst tightening count the number of turn on each side.

Make sure there are an equal number of turns on both sides. I usually do this by tightening one side first whilst counting number of turns, then tighten the other side. Make sure the nuts/quick release with which you tighten the wheel are not loosened too much, if they are the chain tension might increase quite significantly when tightening the wheel nuts/ the quick release (because in some cases the frame bends inwards resulting in a somewhat different chain stay angle which causes the extra tension).

Usually if the chain (not sure if this is the same for belt drive but it should be ) tension is too high you will feel the 'steps' in the wheel /freewheel/casette bearing when turning the pedals by hand (you will feel little bumps every so often whilst rotating the pedals by hand. This could also indicate somewhat worn bearings but chain tension definitely plays a role in it as well.

Another sign of the tension being too high: Spin the pedals to make the rear wheel rotate (whilst the wheel is off the ground), release pedals and see if they stop turning immediately or if they continue to rotate with the back wheel (I am assuming you have a freewheel and are not using a fixed gear), if they do keep turning this can be caused by chain tension being too high (or bad bearings), this could potentially also indicate misalignment of belt relative to rear cog (wheel not aligned with frame) so if your bearings are in good condition and chain tension is good the wheel might be misaligned.

Try loosening the belt a bit and see if it helps (if aligning the wheel didn't help, as long as the belt doesn't slip/run off the cogsyou shouldn't need you could also measure the 'stickout' of the threads of each tensioner using a caliperor other measuring tool and compare both sides and make sure they are (approximately) equal to try and align the wheel.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.