Mp5 on front with 26" x 4" wheel

[Chavivaus]

This is my first built. Running 48 v  13.5 a battery. All good, with the exception of wobbling on front tire., which is true (thats what t bike shop said any way)it  seems like lateral rigidity is not enough. Any thoughts ?

[Bikemad]

Hi andto the forum.

Unfortunately, the resolution of your picture is too small to be able to see exactly how the rim has been spoked, so I am unable to comment on the lateral rigidity aspect of your wheel, but if you grab the tyre where it passes through the forks and apply some sideways force, it should not move easily from side to side between the fork legs. If it does move easily, either the spokes are too loose, or there is not enough angle on the spokes to provide sufficient lateral rigidity for the rim.

Please check out this post for further information regarding the lateral rigidity of wide rims.

If the rim has been correctly trued in both directions (radially and laterally) and the tyre is correctly seated on the rim, then (in theory) the tyre should not wobble.
However, if the wheel shakes violently when you raise the front wheel off the ground and apply full throttle, then I suspect the tyre is either misshaped, incorrectly fitted and/or the wheel and tyre assembly is very out of balance.

If the rim is running perfectly true, but the tyre is running out of true in relation to the rim, you may be able to improve the runout by deflating the tyre, re-seating it onto the rim again, and then re-inflating it to the tyre's maximum safe pressure, before letting it back down to the desired running pressure.

Alan
 

[Chavivaus]

Alan, thank you very much for sharing your knowledge, I just added a couple pics to give you more details, the rim configuration is similar to the one on the Dolmite from your post ( it is a GM kit )
- spokes are .5" from either side of rims center line
- if I push the tyre from the forks, it moves about .25" on each direction (just the rim, no movement on motor or axle)
- when I lift tyre and apply full throttle all good
- wobbling happens when at low speeds you move handlebar left and right to keep balance , or if you let one hand off @ 3/4    of throttle and up

 In conclusion, for what I read on your post, the spokes configuration may be the problem and I may have to get some truing tools and learn how to do it myself

Thank you again

[Bikemad]

The lateral angle on the spokes is going to be pretty poor or almost nonexistent if the holes are 0.5" off centre, as the distance between the flanges is probably about the same as the distance between the alternating spokes in the rim.

Unfortunately, parallel spokes will not be able to provide much lateral rigidity as there is no triangulation or cross bracing effect.

If the spokes are not really tight, try tightening each of the spokes by quarter of a turn and see if it reduces the lateral movement of the rim.
If you start at the valve and keep going in one direction you will know they have all been tightened when you reach the valve again.

If the spokes are still not really tight, it might be worth going around again. 

As long as you tighten all the spokes by the same amount, the rim should (in theory) remain nice and true.



Alan
 

[Chavivaus]

Thanks, I 'll try that first. Will update on a couple days