Front Wheel Oscillation-Part 3: The Resolution

[nicocorea]

This is the third and last in a series of posts about a problem I've been having with the way my new 2008 M50 rides. Links to the first two posts are below.

http://www.motorcycle-journal.com/fo...cillation.html
http://www.motorcycle-journal.com/fo...-part-2-a.html

n a nutshell, the front wheel on my 2008 M50 seemed to hop in the 40-55 MPH range, as if the front tire were out of round. The problem existed from the day I drove the bike off the dealer's lot, and today I have 2500 miles on the bike. After bringing the bike in twice to the dealer to complain--and both times being told the bike was perfectly fine, the dealer finally replaced the original IRC with a Dunlop for free. But the problem was still there. So I concluded that it must be the front wheel, not the front tire. I then took the bike to another shop (unaffiliated with Suzuki) and had them check the front wheel. They verified it was good, but said the Dunlop was bad. So next I bought a Metzeler ME880. The oscillation was still there after the Metzeler install, but the speed at which the oscillation occured narrowed to 50-56 MPH.

Folks on this forum offered many hypotheses to explain the oscillation. I tested each of them and ruled each one out.

Having confirmed that there was nothing wrong with anything in my front end and that there was also nothing wrong with the drive train either, I concluded the only possible source left for my front wheel oscillation must somehow be the rear wheel/tire.

Ever since delivery, it did have two huge weights clipped on to the left side of the rim, and another large one directly across on the right side of the rim. All three weights were on the opposite side of the rim from the stem (and where the tire's dot also was). I asked this forum if anyone could imagine any way that the effects of an out-of-balance or out-of-round rear tire or wheel would be felt in the front, and the consensus was that such a thing was possible.

So my final attempt to solve this mystery was to buy a new Metzeler ME880 for the rear (I liked the front Metzeler so much I figured this would be a worthwhile upgrade even if it didn't solve the problem). Unfortunately, the cheapest price I could find on that tire was at my dealer. But I refuse to spend another dime there, so I paid $40 more to buy and install it at an independent shop.

They mounted the new Metzeler with the dot at the stem and spun it. The balance machine called for 4.5 ounces opposite the stem. Rather than putting 4.5 ounces opposite the stem, the tech re-mounted the tire with the dot opposite the stem. Now the balance machine called for 2.5 ounces opposite the stem. So that's how it was mounted: dot opposite the stem along with 2.5 ounces of weight also opposite the stem.

I drove off and held my breath as I approached the oscillation speed. The road near the shop was rough, but I didn't feel oscillation. I rode to smoother roads and still no oscillation. I really can't believe it, but the problem finally seems to be fixed--$400 later.

While I'm elated, I'm also very pissed off. Why did my dealer--who's supposed to be a professional--not figure this out? Why did they dismiss my complaints and insist that there was no problem when there clearly was a problem? Why do I have a rear wheel that is so badly out of balance that from now on I have to tell tire techs to mount my rear tire 180 degrees off from where they normally would? Unrelated question, but why did one of the bolts holding my front caliper to the fork fall out less than 500 miles after delivery? (They claimed that the normal vibration of a new bike caused the bolt to come loose. That's a ridiculous excuse for a potentially deadly mistake.)

My point is that we pay these dealers handsome amounts of money (how close did you get to MSRP?--I paid $7475 out the door for mine), and they apparently have monkeys assembling these bikes. Caliper bolts that simply fall out? Delivering a bike that requires over 4.5 ounces of weight on one side of the rim? Not being able to correctly diagnose my wheel oscillation? Ridiculous!

The only good thing I got out of this was a set of new Metzelers. But the truth is there was nothing wrong with the original tires and that's $400 I could have spent on other, more enjoyable upgrades.

Anyway, let the record reflect the fact that oscillation in the front of the M50 might be caused by a unbalanced rear wheel. This is totally counter-intuitive, but possible.

[VtWoodChuck]

Well Done succinct and on target with your explanation. Is the rear wheel out of spec to have so much weight to balance. By gosh you tried 3 rear tires, so you cannot blame the tires. Glad you have the problem solved and that you have shared it with us. The dealer should have been a better allie.

[SNAFU]

Good to know your problems solved, but man I feel for your frustration in the whole process.

Ride safe.

[RowdyRed94]

I'm glad you got it sorted. Realistically, though, the dealer doesn't make much at all off the sale of a new bike unless some sucker pays MSRP. Still, they do owe you a functional, safe bike.