Topic: I got a shimmy

[MJL]

I know the vibes are from being out of round, but would that also cause a shimmy?

[jason teamshralp]

by shimmy do you mean side to side?

Remember when pulling a spoke tighter, you must release that pressure on the other side of the rim. Also if you have a hop(out of round) you must pull the high spot and release the low spot. and check after all little adjustments.

[Johnie]

Yep...appears from the video the wheel needs to be trued a bit.  That is done by working with the spokes.  Tedious and detailed work.  Good luck and let us know how you come out.

[MJL]

by shimmy do you mean side to side?

Remember when pulling a spoke tighter, you must release that pressure on the other side of the rim. Also if you have a hop(out of round) you must pull the high spot and release the low spot. and check after all little adjustments.

yes, the bars shake side to side a bit. There is a hop too, which I believe is the tire being out of round. they are old generic chinese tires and are going to go.

But, could the out-of round tire cause the shimmy or is that something else?

[Johnie]

Sure...an out of round cheapola tire could cause that too.  I watched the video a few times and tried to concentrate on the rim and background.  Looks like the rim goes back and forth a little as I compare it to the background.  That would lead me to think trueing of the center hub via the spokes.  Just keep in mind I am watching the video...what do you see in real life?  Does it look like that?

[MJL]

It's hard to see what's going on when I am riding, as the tire and rim both seem out of round. What I did for the video is put it on center stand and support the front under the oil filter. It appears that spinning the tire by hand causes the tire and rim to both move.  I'm going to put a dial indicator on it and check the rim.  I do have a couple dead spokes. Not sure if I want to tackle that myself or have the shop do it when they do the tire.

[Johnie]

I agree...if the tire and rim both shimmy together, then the hub needs tweaking.  Did you put the bike on the center stand and in 1st gear and let it idle with the tire rotating.  See if you can see how it moves then.

[jason teamshralp]

Take the tire off and see if the rim is out of true. If so try truing it yourself. If it gets worse take it to a shop and have them fix it and mount a new tire. DO NOT STRIP THE NIPPLES!

[kghost]

If its an old, hard tire ....junk it and buy a new one.

While its off you can check the rim properly for true.


BTW...sounds like your front brake is dragging...least thats what the sound in the video was like.

[MJL]

If its an old, hard tire ....junk it and buy a new one.  That's the plan anyway

While its off you can check the rim properly for true.


BTW...sounds like your front brake is dragging...least thats what the sound in the video was like.    Possibly, a brake rebuild is going to happen soon.

I agree...if the tire and rim both shimmy together, then the hub needs tweaking.  Did you put the bike on the center stand and in 1st gear and let it idle with the tire rotating.  See if you can see how it moves then.

That's the front tire, mate.

[750K2]

looked like the front brake was dragging to me too

[andy750]

Check your tire pressure - a cause for my low speed (35-40mph) shimmy on the front. I had it at 28psi = shimmy, increased to 32 psi and shimmy gone and bike felt great. I had Bridgestones BT45 though...soft, supple, super-sticky rubber....no cheap Chinese crappy rubber on my bike 

good luck
Andy

[mystic_1]

OK, so I watched your vid and used my mouse pointer as a "virtual dial gauge" and from what I can see all of your radial movement seems to be coming from the tire itself.  The rim seems OK to me.  I noticed than when you pushed the wheel with your hand, the front end was deflecting slightly so it LOOKS like the rim is moving, but only when you're actually pushing.

mystic_1

[strangedaze39]

I think I have a similar problem. When you ride does it have a kind of odd bounce on the front wheel at times? It's hard to say because mine only does it at certain times and it could be my front suspension. I would take it to a shop that does motorcycles I've noticed tire guys normally really earn their money (takes a lot of experience and time to do one well)

[KingCustomCycles.com]

I have had bad luck with Cheng Shins Hi Max tires being out of round, and with flat spots, even when new.  I had a hop and bounce on 3 of my Bobbers and the new Barracuda Cheng Shin cured all the problems.