Cayman Rear Tyre Wear

[Motorhead]

I just checked the tread depth on the Pirelli P ZERO rear tyres of my Cayman, fitted with 19" wheels (265/35/ZR19 N2).

Outer/Centre/Inner depths for both tyres are 3mm/4mm/5mm respectively - indicating some positive camber - which rather surprised me as I thought that the rear suspension should be set up with negative camber (-1.5deg?).

Can anyone with a similarly equiped car - Cayman or Boxster - comment on the wear pattern and/or give me the specs for rear suspension alignment?

Looks as though some new rear tyres and a Centre Gravity suspension alignment check are in order!

Jeff

 

[Richard_Hamilton]

I've done about 5000 miles on the Michelins on mine, and they seem to be wearing evenly. I haven't yet had a trip to Chris, but it is on my to-do list. -1.5° is correct for rear camber.

 

[cayman]

I took advantage of a Boxster test drive a couple of weeks ago and as part of their complimentary car check Porsche East London reported that my rear Pirelli P Zero 19' both had outer 6mm centre 2mm and inner 2mm, after only 8,500 miles. The recommendation was immediately fit two new tyres at an eye watering cost. Having visited Halfords to buy a type tread gague I checked them several times and at different spots and decided that it was actually outer 6, middle 4 inner 4, these seem to produce the opposite set of results to Jeff. Welcome any comments.

 

[Motorhead]

Thanks for the input chaps. Interestingly Martin, my Cayman's covered a similar mileage - about 8,200 miles. I note that the tread depths were listed as being 6mm across both rear treads when I had it serviced last year at 5,800 miles. It seems as though either the Pirellis are prone to a rather strange wear rate or the OPC technicians can't read their tread depth gauges properly.! My front tyres still have plenty of tread left, so I'm trying to source a couple of P ZERO N2s to comply with the Porsche Approved Warranty. Wish me luck. Jeff

 

[spyderman]

ORIGINAL: Motorhead My front tyres still have plenty of tread left, so I'm trying to source a couple of P ZERO N2s to comply with the Porsche Approved Warranty. Wish me luck.

Good luck with that because the only Ns I've seen for ages are N4! I don't think the OPC will be too worried about different N numbers so long as they're N all round. Chris.

 

[BrianJ]

My Cayman S did about 25k on its first set of 18in Michelins, wearing evenly across the tread. The second set only did about 10k before they were both worn on the outer 2 inches or so. Had 4-wheel alignment done. All 4 were outside tolerance and having been aligned, handling is transformed - now like I remember when new.

 

[Buddy]

I got about 16,000 out of Continental N1's, 22,000 from Michelins and have currently done 8,500 on Bridgestones with plenty of tread still left. Past wear patterns were not so high side to side as those mentioned above but of course the rear tyre wear is usually the reason for changing tyres and trying to stay with the N rating same all round.

 

[BrianJ]

Just rereading the above - it wasn't the camber that was the main problem on mine, it was the toe-in, which had somehow got to 34' and 23' on the rears vs the 5' +/- 5' from Richard's table (mine non-PASM). Fuel consumption has also improved as well as handling.

 

[Motorhead]

I have a feeling that it's a toe-in issue with mine too Brian. But, assuming the OPC technician's measurements were correct, I can't see how it's gone from an even wear pattern to the current wear in 2,400 miles, especially since I've not banged the suspension on anything and the wear is even side-to-side. As I said before, unfortunately I'm going to have to get the alignment checked to answer the question. Jeff

 

[uknick]

I seem to have had the same problem at the front of my Cayman, scrubbed a set of front tyres in 5k, inside tread all but gone on both wheels. First set lasted 25k miles and driving style not changed since new tyres fitted. Alignment checked by OPC and camber well out at the front, but hardly at all at the rear. Alignment now back to factory settings (thank you to OPC for not charging as it was over 3 months since they had adjusted it at 25k miles) and new tyres purchased at the front from OPC. Now measuring tyre wear all round every couple of hundred miles to see if there is still a problem at the front.

 

[Buddy]

Nick, It sounds like the OPC got your alignment wrong at 25K not only should they have done the correction for free but did they give you a good discount on the replacement tyres?

 

[uknick]

ORIGINAL: Buddy Nick, It sounds like the OPC got your alignment wrong at 25K not only should they have done the correction for free but did they give you a good discount on the replacement tyres?

A little on the tyres. Last time I sourced the tyres elsewhere, but this time I wanted them to do the complete set up, so if there is a problem again, it is all their work. Their view was I hit a pot hole; classic case of nothing to prove otherwise. But, let's wait and see how these tyres wear. I have to say though, the handling does feel a lot better this time. And that is from a luddite with regard to car control.

 

[chrisH]

ORIGINAL: Motorhead I have a feeling that it's a toe-in issue with mine too Brian. But, assuming the OPC technician's measurements were correct, I can't see how it's gone from an even wear pattern to the current wear in 2,400 miles, especially since I've not banged the suspension on anything and the wear is even side-to-side. As I said before, unfortunately I'm going to have to get the alignment checked to answer the question. Jeff

Jeff, it seems mine has got a similar problem, also with Pirelli P Zeros on 19ins and 8,900 miles. When it was 111 point checked for extended warranty at 5k the tyre wear was even but now it feels like the inner depth is fine but the middle and outer is very low both sides. Could it be overinflation, I run mine at 2.3 bar at the rear? Whats the latest with yours, did the OPC tell you to get the relaignment checked at a tyre specialist or take it in under warranty for them to check it FOC? Chris

 

[uknick]

Interesting thread this. I wonder if there is a flaw in the Cayman suspension system. Or are we just unlucky?

 

[chrisH]

Nick, You are running Gen I on 18ins, what make of tyres and pressures?

 

[uknick]

Gen 1 2.7 with 18" Bridgestone N0 Running handbook pressures 31 at front 37 at rear.

 

[chrisH]

37 PSI is 2.6 bar and a lot higher at the rear than the Gen II on 19ins but the set up is different.

 

[Motorhead]

ORIGINAL: chrisH

ORIGINAL: Motorhead I have a feeling that it's a toe-in issue with mine too Brian. But, assuming the OPC technician's measurements were correct, I can't see how it's gone from an even wear pattern to the current wear in 2,400 miles, especially since I've not banged the suspension on anything and the wear is even side-to-side. As I said before, unfortunately I'm going to have to get the alignment checked to answer the question. Jeff

Jeff, it seems mine has got a similar problem, also with Pirelli P Zeros on 19ins and 8,900 miles. When it was 111 point checked for extended warranty at 5k the tyre wear was even but now it feels like the inner depth is fine but the middle and outer is very low both sides. Could it be overinflation, I run mine at 2.3 bar at the rear? Whats the latest with yours, did the OPC tell you to get the relaignment checked at a tyre specialist or take it in under warranty for them to check it FOC? Chris

Nothing to report yet Chris, but I've got a booking at Centre Gravity in about ten days for an check and adjustment. A bit expensive but I know that they'll do an excellent evaluation and I'm hoping that it'll sort out a handling quirk that I've always thought needs investigating. Like you, the 111-point check at 5,800 miles listed the tread depths as 6mm across the treads on both rear tyres, so I've not checked the depths until recently and found the significant variations both of us have reported here. I've stuck rigorously to the recommended front/rear tyre pressures of 2.2/2.3bar and would think that over-inflation would tend to cause more wear at the centre of the tread; the wear pattern we're experiencing would tend to indicate a camber error or excessive toe-in. Actually, I hadn't considered contacting the Hatfield OPC since it's not really a warranty issue - like uknick, they'll probably say that I've hit a pothole - but might give it a try. Maybe if I purchased the tyres from them they'd throw in an alignment check FOC. If you do the same, perhaps we can compare notes. I'll keep you posted. Jeff

 

[chrisH]

ORIGINAL: BrianJ Just rereading the above - it wasn't the camber that was the main problem on mine, it was the toe-in, which had somehow got to 34' and 23' on the rears vs the 5' +/- 5' from Richard's table (mine non-PASM).  Fuel consumption has also improved as well as handling.

Brian, What was the OPC's position on this problem as it sounds like Jeff's and mine are suffering the same change in wear pattern as yours? Didnt they take any responsibility for the adverse tyre wear and offer you a good deal on some new ones? Can't adjusting toe-in and camber angles be done by my local tyre specialist to the correct figures as Richard posted? Is it worth going to CoG as they are a long way away?

 

[CLIFFWILKINS]

The most accurate 4 wheel alignment system is the Hunter system with the matching ramp all done by laser. OPC use the Beissbathe system its ok but this system uses heavy cameras on the wheels and not as accurate as the Hunter system. Remeber any wheel alignment system is only as good as the person using it. Also has it been calibrated regular? Just had mine done at JZM in Kings Langley the full works corner weights road heights wheel alignment. Most of you will get away with a 4 wheel aligment GT3s are a bit more sensative. On the Cayman tyre wear I had a Cayman S Sport my tyres wore even and it was never even aligned in my short ownership.