vibration

[geniusloerts]

Ok so I had some new tires mounted front and back. I had wore out the back one, the front one I thought was a bad tire because it vibrated pretty bad at 85mph.

so I went to try out my high speeds yesterday and I still had the vibration in the front any suggestions?


gratis

-GENIUS

[BigDick]

I had this problem too, but mine magically fixed itself. . . . I would suggest to double check, make sure your wheel and tire are clean (bits of mud etc could throw off the balance) and get a fork brace if it's in the budget. If you do a search, the front end is one of the weaker components on these bikes. Most do the fork brace and progressive fork springs and say it's like a totally different bike.

[geniusloerts]

the front tires are clean, UBER clean. and the tire and wheel were just balanced at the shop.

puzzlemet

[CatatonicBug]

it vibrated pretty bad at 85mph.

Built in speed-bumps? Telling you to slow down!

[geniusloerts]

.......nah!!!

[DiverRay]

Check the steering stem bearings. Put the bike on the center stand, put a jack under the front frame and get the front wheel off the ground. With the wheel strait ahead, push LIGHTLY one direction or the other. The wheel should turn all the way ON ITS OWN. If you feel ANY type of "bump" or rough spots, the bearings need to be replaced. If the wheel just does not go all the way, the bearings are probably too tight.
The next check is the brakes. While you still have the front end up, look at the rotors. They should BOTH be centered in the calipers. If not, you will need to loosen the pinch bolt and move the one fork leg to center the rotors.
My $0.02

[BigDick]

yeah the stem bearings too, what he said ^ (duh me! )

[trbig]

I've never had a tire mounted and computer balanced at a shop that was very smooth above 75-80. It would seem that a computer balance would be better... but ever since I started mounting my own and static balancing them with some bearings.. I've never realized that it was possible to get a good balance. Get on a good smooth road, and it's like riding on glass as fast as you want to go. The final straw for me taking it to the shop, was after getting a rear tire mounted, they didn't mount the brakes right.. so they locked up on me the first time I touched them. I loosened the bleeder screw and rode it back and had them fix it.. and the guy made the statement.. "Pffft. That's what I get for working on crap that's older than I am." So I imagine since my bike didn't say GSXR or R1 on the side, they were slapping weights on it half-assed and figuring I'd never notice on that old POS I ride..

Now my MOTOR has a weird vibration from @ 89-92 mph.. but it's more of a buzz than a bounce. So I usually just push on through that small envelope and ride a little faster or slower than that. It does help in one aspect.. I can tell what speed I'm going at that point while making a pass! lol.

Tod

[BigDick]

One more consideration, could this be what you're describing?

[geniusloerts]

no, its not the bars. could the amount of air in the tubes matter?

[geniusloerts]

update

so I got the front end up in the air to check the steering bearings in the triple tree, they seemed ok, it was smooth left to right and there was no play when I lifted up on the wheel, pushed down, sideways, etc...

this one is starting to kick my butt......

my friend that was riding next to me says the wheel/tire looks pretty crazy bouncing like it does.

maybe I will try and get a video of it.


Any more ideas?

[DiverRay]

If your friend can see the wheel bouncing, you need to have the wheel balanced again! It's that, or the wheel is out of round. I would think the balance would be the problem, though it could also be a bad tire.
A trip back to the shop is in order....

[trbig]

Those Arkansas boys like to go out and run over small helpless creatures for fun/sport. So maybe you hurt the rim somehow? You could put the bike on centerstand if you have one.. then use a jack under the oil pan to get the fron wheel off the ground. Get in front of the bike and spin the tire.. see if the rim spins true on both sides.. then watch and make sure the tire tread spins straight and true also. If it does... I would go ask for the tire to be rebalanced... and see if maybe someone that was older than the bike could check it out.


Tod

[dbeardslee]

I had a similar problem with Betsy, and after replacing head bearings, wheel bearings, installing a fork brace, and everything else I could think of, I took the tire off. I put the axle through it and layed it across a couple chairs. I spun the tire and each time it came to a stop I would put a little piece of masking tape on the low spot. After five or six spins I had five or six pieces of tape within an inch of one another. Strangely enough, that was right where the tire shop had put the wheel weight. I popped the weight of, balanced it myself, and never had another problem out of it.

[Ivan]

Road Force Balancing

Hunter Engineering come up with a really neat idea. They dubbed it road force balancing. When balancing a tire they have a roller that presses againt the wheel and the machine measures how much force the wheel and tire put on the road at any given position. They then measure the run out of the rim and match the low spot of the rim to the high spot of the tire.

It sounds like snake oil, but even brand new michelins are prone to being out of round, due to cooling differences and such. Road force balancing can make a Geo Metro ride like a Lincoln Town Car.

Since there is no way to road force a MC tire, I would suggest putting dome easily discernible marks on the wheel and tire. Break the bead and move the tire 180º in relation to the rim. Ride it and see if it is better. If so, try it again with it turned an additional 90º. You may have to try it several times to get it minimized. Then use a bubble balance or a stand balancer to balance the weight.

Lastly, I would recommend you get it taken care of before there is any damage to the tread from un even wear. Once one half of the tire circumference starts wearing faster than the other, most any tire will never come back from it.