I'm riding a 20 inch primo tire on the front of my tandem I notice that the tire is wearing on side about 1/2 inch from the center. I tried flipping the tire around so now I have ware on both sides but the rubber in the center is still fresh with tread pattern showing the sides are flat and woren. I never ride with less than 100psi in the tire. It concerns me that the tire is not wearing out where the rubber is the thickest. Any suggestion or comment on these Primo 409 tires. Thanks

I took this tire off the bike and put on an s lick better safe than sorry!-Bruce

Well, since you flipped the tire around and it wore on the other side, it is unlikely that it is the tire itself.

Therefore, something is making that side of the tire spend more time in contact with the road.

It could be a camber problem. Make sure that with the frame perfectly vertical, the front tire is perfectly vertical as well. If it were crookedly mounted in the fork, or if the fork is bent, that could be a problem.

It could be you ride the bike crookedly. Get someone to watch you riding and see if you lean the bike over consistently to one side. That seems unlikely especially on a tandem, plus I'd think that would result in both tires wearing on one side.

It could be you mostly turn in the same direction. Do you have a "normal" route you ride? Check it out, are almost all the turns the same direction?

This is very strange. You should have the opposite wear pattern on the rear tire if the frame of fork is tweaked.

Does your front tire track straight when you are going forward? If the front tire is off camber, the bike will want to pull to one direction or the other. Ride without hands (carefully!). What does the bike do?

Go in a straight line and have someone watch from the back. Does the bike "Hound-dog?" That's when the rear tire takes a different track from the front.