"Unsteady" Feeling From Tire Mismatch?

bdarling · Post by **bdarling** » Wed Sep 30, 2009 6:51 pm

Hi everybody!

I replaced my back tire with a Zippy about 3000 miles ago and the shop originally put the tire on backwards. Everything felt fine, in fact the scooter felt very sure-footed. After about 500 miles I started having a problem with the tire deflating at speeds over 45 mph. When I took the tire in, the shop discovered that the valve stem had been installed incorrectly, so they replaced the valve stem and re-mounted the tire, going the correct direction this time. When I put the tire back on the scooter, I immediately noticed that the rear seemed to sway a little bit during turns. Maybe it's not swaying, but that's the best description I can think of to describe the sensation. I have been watching the tire pressure and it has stayed spot on at 30 psig. Everything is tight, but the handling remains--shall we say--less than confidence-inspiring. The front tire is the stock 3.5 by 10 and the rear tire is a 3.5 by 10 Zippy. Has anyone else had a similar experience? At this point I'm considering having the tire reversed again.

-Blake

broke · Post by **broke** » Wed Sep 30, 2009 7:12 pm

My Pirelli's have an indicator showing the correct rotation of the tire if it is mounted on the Front or on the Rear of the bike. (you swap it depending upon which end of the bike you install it on.) Does your tire have an indication showing correct rotation for rear? Why do you know it is on correctly now and was on incorrectly before?

I had some serious vibration from my Pirellis when they were first installed. It wasn't until I made the shop remove them and re-mount them that the bike became comfortable to ride again. There seems to be an opportunity for the quality of the mount to affect the comfort of the ride

bdarling · Post by **bdarling** » Wed Sep 30, 2009 7:18 pm

Well, there is certainly an indicator with text to help determine the correct orientation. The problem is that, in my eyes (engineer that tends to over-think everything), the indicator has lots of room for creative interpretation. When the tire was first mounted, if you rotated the tire so that the text was on top of the tire, the rotation arrow corresponding to "rear" was opposite the direction the tire would turn as the "pusher". After remounting the tire, the arrows seem to jive with the direction of rotation.

**Disclaimer: this is all from memory, so there may be some errors in my statements. Bottom line, the tire is correctly mounted now...per the manufacturer's instructions.

polianarchy · Post by **polianarchy** » Wed Sep 30, 2009 7:33 pm

IIRC, pugbuddy dealt with this exact same problem a few months ago. You could PM him & see what he did.

pugbuddy · Post by **pugbuddy** » Thu Oct 01, 2009 4:19 am

I had some uncomfortable riding when I had a mix of tires on the Buddy--Michelon S83 all weather tire on front, stock "sport" tire on back. I swapped the back tire to a S83 and, after a bit, the smooth ride returned (I think, after the swap, it took me a while to "re-acclimate" and feel confident about the ride again).

Someone on this forum mentioned that it is a bad idea to have two different tire styles/models on the Buddy. I found that once I changed to one style/model of tire, my problem when away.

If I understand you correctly, you have two "sport" tires on your Buddy so this may not be the same problem.

rajron · Post by **rajron** » Thu Oct 01, 2009 1:21 pm

The Zippy 1 is directional – when used as the drive tire there is a specific direction; and when the tire is used in the front it actually goes the opposite direction, so the arrows look like this drive ← → front – you must decide; but, remember they are only referencing to when the skoot is going forward.

jijifer · Post by **jijifer** » Thu Oct 01, 2009 2:40 pm

I don't know how it works but one thing Motorsports said was that with the zippy's were reverisble threads so you can flip the back one around. Why or what for I don't know but other tires are sold as rear and front due to tread, i think.

did you keep the original on the front? Do you ride with that carrying case a bunch and full? my zippy1 only were good for about 4.5k miles and I don't usually haul stuff.

loodieboy · Post by **loodieboy** » Thu Oct 01, 2009 3:12 pm

I ran with a Michelin S1 on the front and stock on the rear, and it was horrible. Same sensation you describe. Now that a S1 is on the rear as well, all is well

. Love them S1's. It may not be universally true, but mismatching doesn't seem to be the way to go.

Cheshire · Post by **Cheshire** » Thu Oct 01, 2009 7:58 pm

I'm wondering if it has anything to do with tire wear. Most tires I've seen wear a touch off-center, I want to say left of. If you don't have many miles on that tire since they turned it around, it might just need to be re-scrubbed back in. I'd say give it a hundred miles and see what that does to handling...just don't go crazy in the curves.

DennisD · Post by **DennisD** » Thu Oct 01, 2009 8:24 pm

I wonder if it doesn't have more to do with rubber compound. The "sport" versions are softer, give better traction and wear faster. I would think that if you put a soft tire on one end and a harder on the other you would get the wiggle sensation you're talking about. With matching compounds the softer tire flex matches instead of one trying to flex and the other trying to maintain its non flex position. Makes sense to me. So if you're going with more of a performance tire, buy two. If getting something that matches the original stock tire, buy one.

bdarling · Post by **bdarling** » Thu Oct 01, 2009 9:22 pm

I'm slowly getting used to the feeling, so I think I'll just ride it out until the front tire needs replacing. The guys at Motorsport said to expect to put about 3 new rear tires on for every front tire...so I'll probably be posting the same problem again in about 2000 miles