Do I have the right wheels and tires?
 

I bought my 1997 65,000 mile Boxster at the end of November, AS IS. One of the main reason for purchasing this car was for the 19" mesh style rims. Within a couple of days of my purchase, I had to replace the two rear tires as they were bald and held no traction in the rain. I also noticed in dry conditions, the rear end of the car was squirrelly. I purchased a couple of decent used tires until I had the money to buy a brand new complete set of four. After buying those tires, I had a rear lower control arm and a rear strut replaced, both on the same side. Within weeks, I had to replace the rear tires again. That time, I had the car aligned. Less than 3 weeks later and I had to purchase yet another set of rear tires. I took the car to be aligned again at a reputable place referred by my mechanic. Less than 3 weeks later, I had to replace the rear tires once more. Three weeks after that, I had to replace the tires again. That's five sets of tires in four months!!!

It's been two weeks since my last tire purchase and it is evident that they are considerably more worn than the day I purchased them. Last night while driving on the highway in the high speed toll lane it began to rain. The rear of the car began to swerve all over the road. Needless to say, it was very unnerving for both myself and my passenger.

My mechanic is beside himself, as he sees nothing wrong with my rear suspension other than what was already repaired.

Used or otherwise, why is my car eating tires so quickly?? Why am I unable to control the rear of the car in the rain? I currently have 245/35/19s in the front and 285/30/19s in the rear. I have also put on 295/30/19s and 275/35/19s. At this point I am afraid to spend alot of money on brand new tires until I can be assured that purchasing used tires is the source of all my troubles.

Any feedback is greatly appreciated!!

Those are absolutely not the right rims for your car. The suspension on that model year is not designed for anything larger than 17" rims, and running 19's could well be unsafe. If you do a search you'll find a few threads on the topic in this forum.

Get some 17's and run 205/50's on the front and 255/40's on the back. It will handle and ride much better. I'm going into my third season on the same rubber (Michelin) and I still have loads of tread left.

19's won't cause the problems you're seeing. Something is worn out or broken. Take it to Mechanic who specializes on Porsches, Pedro is in Florida. Is this your only car? I would not coutinue to drive a car in that condition, especially with the cost of so many tires!

Some thoughts:

(1) My experience with used tires is that they wear very quickly. Not in three weeks, but they do seem to wear out awful fast.

(2) Has anyone checked the 19" wheels? Out of true?

(3) Borrow a set of 17's with stock size tires from a friend, local mechanic, or a forum member near you. Is the rear end still loose?

(4) Mechanically could be bent suspension, wheel hub, etc. Have another mechanic or **gasp** the dealer look at the mechanical bits.

Let us know if you learn anything further.

First of all, what brand of wheels are these ? And what are the specifications (i.e. width and offset) ?

You need to very carefully examine the area where the forward engine bulkhead meets the rear chassis members, looking for deformation and particularly evidence of cracking. This area, along with the rear suspension mounting points were significantly strengthened in the later cars after Porsche discovered wheel diameters larger than 17 inch over stressed them on the 97’s, causing flexing, cracking, and potential failure. This was discussed in an article not too long ago in Excellence magazine.

I know that this response will cause a litany of “I run 57 inch wheels on my 97 with no problems”; but once you have seen on of these cars start to flex and come apart, it is pretty chilling. I’ve also read that one of the dead give away’s that something is wrong is that when you try to jack up one side the back end of the suspect car, it tends to twist before picking up both wheels on the same side the way an intact car does.

True, I should have been more clear in my post, the wheels themselves aren't the problem, the damage they may have caused is another story.

Here is the description of the changes they made in '98 models
 

to correct the problems that exhibited with spirited driving with wheels larger than the stock 16" or 17" option in the '97.

18” wheel option with rear chassis reinforced to accept new wheels. Rear body structural change included redesigned wheel wells and coil spring mounts, lower engine compartment bulkhead, rear wall cross-member and rear axle mount reinforcements.


It could be that the basic body structure that the rear suspension is hung from has deformed and is flexing and thus throwing the suspension geometry off and you are essentially dragging those rear tires across the pavement and abrading them to death.

Good luck. And there is no way I'd drive it before a true Porsche expert tells me it is safe. I've been driving a car watching through the rear view mirror as my suspension parts bounded along behind me off the road..it isn't fun...or safe.

BTW, one of the downsides of 19" tires is cost.

All good advice. Have all 5 sets been used? 295/30...I didn't even know that would fit on a 97'. Anyway ya find a good Indy, I think your description of how it drives in the wet is a clear indication something is really wrong, as Mike says, "dragging" sounds about right.

19x8.5 and 19x10.5. Honestly, I do not know what brand. I will attempt to post a pic of the wheels. Being new to this site, I am still navigating my way around it.

My mechanic is a Porsche specialist. Claims he's been doing it for over 30 years. He's had it up on the rack many times with me under it. Neither of us have seen anything out of the ordinary other than the items already mentioned.

WOW...by far the most sensical response as far as I can interpret. But why couldn't my mechanic who has supposedly worked on Porsches for over 30 years have determined this??

Ahhh, and like Mike's response, your's too makes complete sense. I am no stranger to owning luxury sports cars, although this is my first Porsche. I just don't understand why no one has been able to diagnose my problem after 5 months, wheras in one day, I have gotten so many amazing armchair results!!

Thank you.

Yes, all five sets were used. As stated in my original post, I had just bought the car and wasn't prepared to dump money into tires just yet. And when the first set of used tires were destroyed after a few weeks, I decided to stick with used until it could be determined why the problem was occuring to begin with.

And as far as the 295/30s...LOL, that was an accident. I had to use my Dad's truck to pick them up and deliver them to a tire place to have them installed. When the car was in the air, the tires rubbed against everything. However, when the car was on the ground it was ok. Needless to say, those tires lasted me two weeks. Shortest lifespan by far!!

You bought used tires... well that might just explains it.

You're driving on used tires :)

A 10.5 inch wheel is a red flag right there . I'd love to know what the offset is in order to make that wheel fit. Is there a large spacer involved ?

But where do you even find used tires in the first place? It's just like underwear... who sell them used?

It's as easy as going to your local tire/alignment shop. I bought some used tires for my Toyota 4x4 to get thru inspection. They go on for 1 day every two years, then back in storage!

On occasion, I've seem some low mileage thongs like this one come up for sale on ebay .

I'll add that with the wheel width/tire combination, I'd look very closely for signs of rubbing inside and out, as I don't know how you'd get that combo to work. Any signs of rubbing on the fender liners or struts?

Sounds like you truly did purchase the "Boxster from Hell"

When I got my first car ('67 Parisienne) as a teenager, all I could afford were used tires. Used to get them for $10 each from the local wrecker. Never had two tires the same brand on it the whole time I owned it!

Lets go easy here folks
 

as the problem isn't used tires. (The set I just took off after 15k miles and not because they were worn out was used by someone else before I bought them. Nothing wrong with used tires that makes them inherently bad as long as they are the right tire and balance out right and aren't aged out. I bought a set of take-offs essentially for the price of the wheels with no idea of the miles the original owner had put on them).

You're a funny guy, Mr. Danger!! But I must tell you... in South Florida, used tires are all the rage. And trust me, I always buy matching tires - Michelin Pilots. Unfortunately, finding two alike tires with similar wear can be a problem, which is why I have gone between 275/35s, 285/35s and 295/30s.

LOL!!

The only rubbing I had was with the 295/30s when the car was in the air. When the car hit the ground, however, the wheels and tires pulled away from the suspension. I must admit, the 295/30s from the rear view looked pretty awesome. Unfortunately, those tires had the shortest lifespan!!

It's not the problem of used tires. The problem is unknown age & wear pattern. Were they mounted on wheels within proper recommended width? Were they heat cycled often? That's just few of the many problems when you buy used tires. OP didn't state how the tires are worn when they were replaced.

Provided his mechanic with 30 years of service knows what he's doing, I would put my bet on the tires.

http://autoblog.royfoss.com/images/t...ar_pattern.jpg

Sorry but I also cannot agree that it is "just" a tyre problem.
If the OP had gone through one or two sets of tyres, then yes, probably due to cheap Chinese jobs with a questionable quality & lifespan. But FIVE sets in as many months??
I would like to see the wear patterns of the worn tyres - that would (should) give some indication to the problem. But I don't think any 1997 Boxster is going to handle very well with 19" wheels on anyway, especially if the larger wheels have caused wheel bearing or structural damage to the rear end as per what Jeff (JFP in PA) says.
If there is any weld or componant breakage to the rear structure, the rear end will move around like a dogs tail. Anyone having ridden a motorcycle with worn out swingarm bearings will know what I mean - feels OK in a straight line, but when you change directions its as loose as a drunken sailor, causing extreme tyre wear......

I have 17,s and 19's for my late 97. The original 17's with bridgestones seem to turn in much better and makes the car generally more nimble but the 19's with michelins on seems to make the car feel smoother for some reason, it's hard to explain but it's like you can feel the extra inertia from the larger wheels and it seems to affect the acceleration and de-acceleration too. I actually prefer the 19's, I've also experienced no odd tyre wear even though the 19 inch Michelins' had been fitted to a 996 perviously.

ps check your vin number on your 97, from what i can gather if your's is a late 97 (should have a "W" in the vin number) then your car will be a 98 model as mine is.

tire change
 

I'm due for a tire change on my 2002 Boxster. I'm looking at the Michelin Pilot Sport PS2, I need -17s, anyone here has comments or experience with these tires? I live in South Florida, hot year 'round, don't drive much, but when I do I like to open it up :)

Thanks,

I have pics of two different sets of tires that wore the same exact way. I just don't know how to post them!! Grrrrr...

The tires wear from the inside out on both sides. Your pic of an over-inflated tire is the best example. However, that many coincidences would be impossible, as each set was installed by different tire stores.

YES, exactly!! Driving in a straight line is fine (and if I remove my hands from the steering wheel, it remains straight eliminating any poor alignment theories). However, when I change lanes, especially on an uneven highway surface, my steering wheel pulls uncontrollably from side to side. It also feels as if the rear of the car is tilting from side to side. In the rain, it's absolutely terrifying.

Hi, guys!! Haven't checked in for a few days and appreciate the recent replies.

I called a local Porsche dealership today and spoke with the service manager. We discussed at length the many theories you all have offered up. He suggested that rather than assume the problem lies with the questionable wheel size and/or the usage of used tires there may be frame damage undetectable by the naked eye.

That being said, I will be taking the "Boxster From Hell" to a friend's body shop to be put on a frame rack. I believe it's called a Star-A-Liner. Apparently, it will be a lengthy process, as it measures every aspect of the vehicle and can actually straighten out any sort of accident induced frame damage.

Honestly, I would rather it be a case of the rims being too big, as the thought of what it costs to straighten out a frame makes me wish my mid-life crisis Porsche purchase never transpired!! Well...almost. I truly do love the car :o

I will report back when I get the results.

If your tires are wearing considerably from the inside out, you may have excessive negative camber. I run neg 2.5 degrees in the rear and do not wear out the tires; however, I put less than 3k miles a year on the car.

Hello everyone...

Latest update on my car is I STILL HAVE THE SAME PROBLEM!!! Or at least a variation of it.

The car was put on a body alignment machine...it's straight as an arrow.

I replaced a rear control arm and a trailing rod that had supposedly bad ball joints with brand new Porsche parts.

I replaced ALL FOUR tires with NEW...yes NEW Michelin Pilots, 235/35/19 on the front and 275/35/19 in the rear.

Had the wheels balanced. Got a four-wheel alignment.

So now, rather than the rear end squirrel about, the steering wheel takes on a life of it's own when I remove my hands by turning side to side as if a one-eyed drunk driver were behind the wheel!!

I give up!! I love this car and do not want to sell it. I just can't keep throwing money away though... What's going on with this car?? And why can't any of the so-called qualified techs figure it out??

One more thing...

I had the conical lug bolts removed, and almost all of the heads were shredded. They were the original factory bolts, and were not for the 19' rims that were put on prior to my ownership.

I installed brand new cone lug bolts. The only result is that they look better than the old ones, yet I had the painstaking task of cleaning and painting the holes where the factory bolts scraped.

Just trying to narrow down any and all possibilities regarding the suspension and wheels...

By the way, I still cannot post pics. However, you posted a photo of a "GT" on 4/20/2011, and those are the same wheels on my car. They were made in Germany and Vertex in Miami sells them for $1,349 each. (Well, not any more, as they have been discontinued.) But the wheel is the Elite Custom Force Design. No spacers. Perhaps I should try a set(?)

tire pressure?
 

Read thru the whole post...
never read anywhere about what tire pressures u r
inflating tires to
this might help eliminate one more variable
Chris

If money isn't as issue you can't do much better than PS2s. They wear fast, but have great traction and are a bit little narrower compared to other tires of the same size. They are also quit a bit lighter than other tires of the same size.
Dunlop Direzza star specs have similar grip, are cheaper, but noisier and heavier than PS2s. Yoko advan neova 08s are also very good, and very quiet. For a weekend driver you can't go wrong with any of these tires, just depends on what's important to you. I tend to drown out the tire noise with the intake wail so I'm running the Dunlops right now. I just bought a set of CCW classic race wheels from a guy on pelican and can't decide if I'm going with one these three or put on a set Michelin pilot sport cups, which you might consider if you only drive weekends.

Tire pressure is fine. I really think that the idiots who put the new front tires on didn't balance them...

This has been an interesting thread and I wonder what is up with the "Boxster From Hell". The OP bought this car because he liked the wheels (mesh), had nothing but trouble from the beginning, went through 5 sets of tires in 5 months, the car handled horrifically in rain or changing lanes, called the Porsche dealer and solicited the forum for advice - but never seemed to have taken the car to an actual Porsche dealer for diagnosis. After all that he still said - "I love this car". We should all be so enamored. I didn't see through the thread (although I could have missed it) if he actually test drove the car or inspected the tires prior to buying. So, what's up BFH?