Hi Everyone, A friend of mine has a Super 8, which she bought new. One day, after it was broken in, I took it out on the freeway to see how fast it will go. At about 55 mph or so, there is a violent wobble coming from the front tire. It is an up and down movement, very much like dribbling a basketball. It was violent enough that I would worry the front end would break off if ridden like this far enough. It feels normal below 55.... 2 motorcycle places have looked at it and say the tire does not need to be balanced! The dealer she bought it from said it was normal. I disagree, and suspect he didn't drive it fast enough. In any case, even with small tires I would think a scooter would be designed to be safe up to it's max speed. If it is not a balance problem, what could it be? Could the tire be out of round? The bike has less than 1000 miles on it, and is still under warranty.
If the dealer is close by I say take it back and let the tech take a 55mph test drive. My zuma 125 has 12 inch wheels and is smooth at 55mph. Has anybody checked the balance of the tire or are they just saying it doesn't need balancing. I would think you could tell if the tire is out of round just by jacking up the front end and giving it a good spin. The dealer test ride seems most logical to me. Maybe you could follow along side to see it for yourself in case he comes back and says it was normal.
Also worth mentioning to make sure the tire pressure is correct. It may also behave a little differently depending on the weight of the rider.
My Super 8 did get a little front end vibration near top speed when it was new but it now it is pretty smooth up to around 70 on the speedo (as fast as it will go) I've got 9200+ miles on mine and the original front tire still has plenty of life left. It sounds like the tire might need to be balanced. Also, check the tire pressure. Recommended pressure is only 29 PSI. Too high of pressure might also cause the problem.
If you can get the front tire off the ground and have a piece of chalk handy, give the tire a healthy spin and mark the low point each time it stops. Repeat several times. If the tire is out of balance the chalk marks will be bunched up instead of randomly distributed.
A violent up and down motion as you describe sounds like an out of balance tire, and not a wobble which is typically a side to side effect. Sounds to me like a tire balance, or better yet replacement is in order.
Hi Everyone, Thanks for your replies. I may just have the friend come over, and take the wheel off and take it down to be balanced. I think what is happening is no one is test driving it over 55 mph. Below 55 it is fine. Also, I don't think my friend has the nerve to just tell them to balance it anyway. Thanks again.
The only way to really know if the tire needs balancing, is to put the wheel on the balancer.If the dealers didn't do this, they don't know if the tire needs balancing or not. But, when you look for a problem , look for all of them; bearings, out of round, loose axel nut, tire delamination, etc.. The dealers might not know what they are doing, or the service writers don't know any better. A mechanic needs to check this out.
