Do I have the right wheels and tires?

[boxsterfromhell]

Originally Posted by mikefocke

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.

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??

[mikefocke]

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).

[ekam]

Originally Posted by mikefocke

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).

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.

[Steve Tinker]

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......

[jonnycool]

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.

[globaldriver53]

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,

[smshirk]

Originally Posted by globaldriver53

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,

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.

[boxsterfromhell]

Originally Posted by Steve Tinker

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......

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.

[boxsterfromhell]

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

I will report back when I get the results.

[jmatta]

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.

[boxsterfromhell]

Originally Posted by ekam

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.

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.