[sickopsycho]

Originally Posted by Triple Jim

Front tires get a lot of their wear when cornering, when you're leaned over. Therefore, looking at the profile, you get two flat areas, one on each side of center, and the center gets a sharper radius than it had when it was new (a little pointy looking).

I don't know the physics of why, but when my front tires get that way, they get noticeably squirly. One symptom is the no-hands wobble around 35 mph that you're seeing. Another I'm getting now on my Moto Guzzi is the tendency to "fall into" turns. When my front tire was new, steering was very neutral, and it felt like I could take my hands off the bar in a turn and it would just keep going around. Now on a sharp turn, the bike feels like it wants to fall over to the inside, and I have to consciously turn sharper to straighten it up.

A new pair of tires for that bike is waiting for me to put them on.

By the way, tire aging is quite variable. If your bike is stored indoors without any direct sunlight on the tires, and if you live away from big cities that have ozone problems, your tires may be fine. On the other hand, if you do park outside in daylight in a big city, they may be getting oxidized and hard by now. I'm in the garage parking, country air category, and six years of aging doesn't change my tire rubber much, on bikes that don't get a lot of miles on them.

Thanks for the confirmation, Jim! This bike was garage kept by the previous owner, and I also keep it in the garage. I checked the tires over closely, no cracks at all (inside or outside tread marks). I can easily dig a fingernail into the rubber, it seems soft to me. I only have VERY minimal (almost unmeasureable- certainly can't see any with my eyes) wear on these tires and I hate to toss all this rubber if I dont have to... but even still since I dont know for certain how the bike spent it's first 5 years I guess I should go the safe route and replace.

Originally Posted by Zaph42

People need to recognize all the interacting factors that cause head shake. It's not just one thing. Bearing wear and slop, head nut torque (and that's the nut under the top triple clamp), uneven side to side tire wear (cupping), size of the contact patch, frame flex and fork flex. If a few conditions line up just right, the head shake appears. Change one thing in this equation and the end result might not = head shake.

Putting new tires on has small chance at changing the equation enough to make the head shake go away. But for most people, replacing the head bearings has a much higher chance of doing something. I've heard a few people say new tires didn't solve the problem, but I've never heard anyone say that new head bearings didn't work.

That said, people should first check the front tire visually by spinning it and looking for cupping, and checking the torque of the stem nut. These are the cheap and easy checks.

BTW, I believe a front tire that is worn with a flat spot, or a sport touring style tire that has a larger upright contact patch is more likely to contribute to head shake. Pointier tires, such as true supersport, or tires that are seriously worn from track use are likely to feel "skittish" and fall into turns but actually be less likely to cause head shake. Two completely different issues not to be confused.

I forgot to mention that this bike, while a 2012, only has 2000 miles on it... and I put 1000 of those (very light riding). So- bearing wear is unlikely. The tires I have on the bike *I think* are the ones that came from the factory. It is a Road Winner RX-01F. Below is a picture of the wear...