Still having tire problems - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Johnny Danger · 01-05-2012, 01:38 PM

Quote:

Originally Posted by fullthrottle52

I agree with the wheel theory at this point. I agee that it should show up during a rf balance but it is the only thing I have to go on at this point except mechanical. I can't imagine buying 3 sets of tires and having all 3 sets bad. That is why I put a set of Michelin Pilots on, to eliminate it being a tire issue. If they can not get the tires balanced tomorrow then I will again go to my INY and put on another set of wheels and tires and do the test again. I also have a Porsche club meeting this monday night and will see if I can get another early model boxster owner to meet me at the tire store where I purchased the Michelins and do a front rim or tire swap. Test drive both cars and see what the results are. Should tell alot. My ony concern at this point is it is getting very cold here now and running around on Michelin Pilots is probably not such a good idea below 30 degrees.

Thanks for all the comments gang. We'll somehow get it figured out.

I'll let everyone know of the results.

I'm thinking that somehow there's an issue with your wheels not being hubcentric. With that said, although an RF balancing machine may be able to detect a bent or out of round wheel, it does not have the ability to calculate "hubcentricity" .

stephen wilson · 01-05-2012, 02:20 PM

Yeah, find someone generous enough to let you run his wheels for a few days, I'd swap all 4 with the donor car. Running the Pilots below 30° won't hurt anything, just be aware or the reduced grip,which will still probably higher than most economy tires. Just make sure there's no chance of snow!

fullthrottle52 · 01-06-2012, 12:29 PM

Well, just as I suspected. I have one front rim tha is out of round. A very experienced tire guy where I bought the tires put both front rims and tires on a balancer. Spun it and by holding an ice pic very steady could tell that one of the rims has a slight low spot on it. It left a mark about 6 to 8 inches long on the inside of the rim. He said it is enough to cause a shake at higher speeds. The other one has a very slight high spot but not nearly as bad as the other one. It still does not answer the shaking issue I was getting at 40 mph first thing in the morning but that seems to have gone away with the Michelins. Now only slight shake at 50 to 60 mph and then gets progessively worse as you go up. After rebalancing again today after finding the flat spots it is slightly better but still very uncomfortable to drive at 70 to 75 mph.

I guess I am now looking for an 18 in OEM Boxster wheel. I have to look at the inner rim to see if they are 7.5 in or 8 in. rims and then start my search. If anyone here has one for sale or knows a good source, let me know.

thanks again for all the input. I hope I can get this resolved soon. I may just have to wait until Spring now, but at least i know it is not tires and can wait.

stephen wilson · 01-06-2012, 12:45 PM

If I've followed this correctly, it sounds like the first tire shop damaged your wheels? That sucks!

Pat · 01-06-2012, 12:46 PM

Glad to hear it was finally resolved.

fullthrottle52 · 01-06-2012, 01:02 PM

I ask that question of the current tire store. He said it is very unlikley that the INDY that mounted the first set of tires (Hankooks) could make the wheel out of round when mounting. If they dropped a rim hard enough it could maybe cause a light (dent) in the wheel but you would probably see where it was dropped.

Does anyone have any experience as to whether a tire mounting system has the ability, with poor mechanic, to actually cause a low spot on a rim when mounting?

I went by the INDY today to tell him I found out what the problem was and he didn't seem real interested in helping me solve my problem anymore. Probably thinks I crazy after chassing ghosts for 3 months, but I know what I know, it still vibrates in the steering wheel at high speeds.

Thanks again.

Ghostrider 310 · 01-06-2012, 01:36 PM

IMO, anyone who cannot ID a bent rim with even an old school spin balancer sucks at using said device. My car arrived with three bent Turbo twists, I had them trued by Keystone wheel and sent the bill to the idiot salesman who took the sport classics off the car and (without knowing according to him) replaced them with bent TT wheels. The company Keystone wheel said Porsche wheels come in frequently, they appently bend very easy. It's also true that if you don't keep the tire pressure right with vigilance a low profile wheel will be far more easily bent.