GT3 - Tyre blowout
Discussion
Looking for a bit of advice...
Background:
I had a rear tyre go on my GT3 on Wednesday. Fortunately I was only doing about 50mph. There doesn't appear to be any damage to the alloy or the rest of the car.
I have had all 4 tyres replaced. The rear's needed doing soon anyway.
Pictured, is the rear tyre that has just come off (the one that didn't blow). I was shocked to see how worn it was on the inside. The outside must have about 3mm left where as the inside is completely shot. I only checked the tread a few weeks ago, and whilst I knew the inside was a little more worn, I was sure it was not this bad. My car has negative camber so it is no surprise that the inside is more worn - I should have checked more thoroughly.
Problem:
Since putting on the new tyres I have noticed a couple of things.
1. Smell of burning rubber coming from both rear wheel arches. Sometimes accompanied by a bit of smoke from the wheel arch where the old tyre blew. Possibly due to a bit of rubber from old tyre stuck to some part of exhaust??
2. If I touch the tyre after I have used the car, the inside is much hotter than the outside. The outside is pretty cold. All pressures are correct.
Both these things happen when I have been for a gentle 10 minute run around town at 30-40mph.
Question:
Is the above normal?? I am worried that the inside of the tyre might be rubbing against something and if so the same thing could happen to the new tyre. Does the wear on the tyre in the photo support this or does the tyre simply look 'well worn'?
Is it normal that after a run around town a GT3 tyre would be very hot on the inside (and ever so slightly sticky) and at normal temp on the outside? Tyres before and after are PS2's.
Any advice appreciated! Thanks for reading!
Background:
I had a rear tyre go on my GT3 on Wednesday. Fortunately I was only doing about 50mph. There doesn't appear to be any damage to the alloy or the rest of the car.
I have had all 4 tyres replaced. The rear's needed doing soon anyway.
Pictured, is the rear tyre that has just come off (the one that didn't blow). I was shocked to see how worn it was on the inside. The outside must have about 3mm left where as the inside is completely shot. I only checked the tread a few weeks ago, and whilst I knew the inside was a little more worn, I was sure it was not this bad. My car has negative camber so it is no surprise that the inside is more worn - I should have checked more thoroughly.
Problem:
Since putting on the new tyres I have noticed a couple of things.
1. Smell of burning rubber coming from both rear wheel arches. Sometimes accompanied by a bit of smoke from the wheel arch where the old tyre blew. Possibly due to a bit of rubber from old tyre stuck to some part of exhaust??
2. If I touch the tyre after I have used the car, the inside is much hotter than the outside. The outside is pretty cold. All pressures are correct.
Both these things happen when I have been for a gentle 10 minute run around town at 30-40mph.
Question:
Is the above normal?? I am worried that the inside of the tyre might be rubbing against something and if so the same thing could happen to the new tyre. Does the wear on the tyre in the photo support this or does the tyre simply look 'well worn'?
Is it normal that after a run around town a GT3 tyre would be very hot on the inside (and ever so slightly sticky) and at normal temp on the outside? Tyres before and after are PS2's.
Any advice appreciated! Thanks for reading!
Just had my MOT and rears are 4.5 to 3.5, outer to inner on standard geo.
If yours are 3mm to shot, it sounds possibly like more track biased geo - perhaps get it put back to standard?
Rubber burning must be fragments on the exhaust though, the camber on the photo doesn't look that aggressive to put the tyre into contact with anything?
If yours are 3mm to shot, it sounds possibly like more track biased geo - perhaps get it put back to standard?
Rubber burning must be fragments on the exhaust though, the camber on the photo doesn't look that aggressive to put the tyre into contact with anything?
SCGT3 said:
Thanks for all for the advice. I'm nowhere near either S&C or CG unfortunately. I think I'll take the car to have a basic alignment on Monday. If it's still not right, I'll then book it in at one of the above!
I'd suggest it's running both excessive camber and more likely toe, if it's heating up excessively.I have a 996T and I bought a pair of rears during the week as I knew mine were very close to replacement and I am swapping over to Techno Sports. I put my car on the hoist yesterday and pulled them off to find mine worn exactly like yours, you can see where the rubber is starting to bobble on the inside edge. The left hand rear is worse than the right hand rear and I put this down to the camber of the road, you could just see the canvas coming through in a patch on mine so I have decided not to drive it until the tyres get changed.
I have had my car's geo checked 4 times in 2.5 years by two different companies both have told me that it is spot on to the spec sheet that I provided out of the factory workshop manual. I was speaking to the owner of a 997t a few weeks ago after I noticed that he had just fitted new rears and he said that his insides wore out too prematurely to the rest of the tyre. I was also at a Porsche Driver Training day earlier this week and stuck my head underneath a 997t to look at the tyres and they were wearing exactly like mine too.
I think that the wear you are showing is normal given factory specs. Here is my LHR:
As for the smoke issue, something is wrong there, I would have a look underneath it and try and see where it is coming from.
I have had my car's geo checked 4 times in 2.5 years by two different companies both have told me that it is spot on to the spec sheet that I provided out of the factory workshop manual. I was speaking to the owner of a 997t a few weeks ago after I noticed that he had just fitted new rears and he said that his insides wore out too prematurely to the rest of the tyre. I was also at a Porsche Driver Training day earlier this week and stuck my head underneath a 997t to look at the tyres and they were wearing exactly like mine too.
I think that the wear you are showing is normal given factory specs. Here is my LHR:
As for the smoke issue, something is wrong there, I would have a look underneath it and try and see where it is coming from.
Edited by NBTBRV8 on Sunday 19th August 07:39
SCGT3 said:
Thanks for all for the advice. I'm nowhere near either S&C or CG unfortunately. I think I'll take the car to have a basic alignment on Monday. If it's still not right, I'll then book it in at one of the above!
I'd take it to a reputable Porsche specialist as a GT3 is a special car and I'd want someone looking at mine that knew what they were doing. JZM have set mine up perfectly and I run a lot more rear camber than you and have no such issues.As has been mentioned, it is possibly a toe issue. If it is toeing out too much then the inner edge will scrub away, plus it will not drive like a GT3 should.
I also change the rears over on mine to try and even out the wear over their life, helps to prevent inner tyre wear
It's difficult to tell from the photos but it does not look like an excessive toe problem as I cant see a too much in the way of feathering of the tyre which is what you would expect to see with a toe problem. You may have to set camber to the positive end of the setting range as you are not loading the tyre up on the outside.
All that said the tyre is not in front of me and I cant see or feel the tyre to have a really good idea. You are doing the right thing by getting the alignment checked out though.
All that said the tyre is not in front of me and I cant see or feel the tyre to have a really good idea. You are doing the right thing by getting the alignment checked out though.
You should find this thread helpful in terms of geo settings, particularly the post by Fiorano on page 4.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Edited by Trev450 on Sunday 19th August 10:39
terryb said:
I'd take it to a reputable Porsche specialist as a GT3 is a special car and I'd want someone looking at mine that knew what they were doing. JZM have set mine up perfectly and I run a lot more rear camber than you and have no such issues.
As has been mentioned, it is possibly a toe issue. If it is toeing out too much then the inner edge will scrub away, plus it will not drive like a GT3 should.
I also change the rears over on mine to try and even out the wear over their life, helps to prevent inner tyre wear
I would agree with the consensus regarding the camber- whether your car is standard or has been adjusted to a more aggressive "fast road" or "track day" geo will only truly be apparent if you have it checked and setup. As has been mentioned, it is possibly a toe issue. If it is toeing out too much then the inner edge will scrub away, plus it will not drive like a GT3 should.
I also change the rears over on mine to try and even out the wear over their life, helps to prevent inner tyre wear
I recently had my 6.2gt3 geo done by jzm to trackway setup, which includes a visually obvious amount of rear camber. It does what it says on the tin on circuit, but, The road tyre wear is frightening and I went from 4mm to canvas and wire on the inside in 300 road miles. They have advised me to run 5psi higher rear pressures to take some of the load off the inner shoulder. I will see how that goes.
By the way the new rears already have a 1mm difference after another 300miles, prior to me adjusting the pressures, so given OP you have replaced all tyres, it might be worth doing the same re. Pressures and get the car checked ASAP before you chew our way through another set of rears in very few miles.
squirejo said:
terryb said:
I'd take it to a reputable Porsche specialist as a GT3 is a special car and I'd want someone looking at mine that knew what they were doing. JZM have set mine up perfectly and I run a lot more rear camber than you and have no such issues.
As has been mentioned, it is possibly a toe issue. If it is toeing out too much then the inner edge will scrub away, plus it will not drive like a GT3 should.
I also change the rears over on mine to try and even out the wear over their life, helps to prevent inner tyre wear
I would agree with the consensus regarding the camber- whether your car is standard or has been adjusted to a more aggressive "fast road" or "track day" geo will only truly be apparent if you have it checked and setup. As has been mentioned, it is possibly a toe issue. If it is toeing out too much then the inner edge will scrub away, plus it will not drive like a GT3 should.
I also change the rears over on mine to try and even out the wear over their life, helps to prevent inner tyre wear
I recently had my 6.2gt3 geo done by jzm to trackway setup, which includes a visually obvious amount of rear camber. It does what it says on the tin on circuit, but, The road tyre wear is frightening and I went from 4mm to canvas and wire on the inside in 300 road miles. They have advised me to run 5psi higher rear pressures to take some of the load off the inner shoulder. I will see how that goes.
By the way the new rears already have a 1mm difference after another 300miles, prior to me adjusting the pressures, so given OP you have replaced all tyres, it might be worth doing the same re. Pressures and get the car checked ASAP before you chew our way through another set of rears in very few miles.
squirejo said:
terryb said:
I'd take it to a reputable Porsche specialist as a GT3 is a special car and I'd want someone looking at mine that knew what they were doing. JZM have set mine up perfectly and I run a lot more rear camber than you and have no such issues.
As has been mentioned, it is possibly a toe issue. If it is toeing out too much then the inner edge will scrub away, plus it will not drive like a GT3 should.
I also change the rears over on mine to try and even out the wear over their life, helps to prevent inner tyre wear
I would agree with the consensus regarding the camber- whether your car is standard or has been adjusted to a more aggressive "fast road" or "track day" geo will only truly be apparent if you have it checked and setup. As has been mentioned, it is possibly a toe issue. If it is toeing out too much then the inner edge will scrub away, plus it will not drive like a GT3 should.
I also change the rears over on mine to try and even out the wear over their life, helps to prevent inner tyre wear
I recently had my 6.2gt3 geo done by jzm to trackway setup, which includes a visually obvious amount of rear camber. It does what it says on the tin on circuit, but, The road tyre wear is frightening and I went from 4mm to canvas and wire on the inside in 300 road miles. They have advised me to run 5psi higher rear pressures to take some of the load off the inner shoulder. I will see how that goes.
By the way the new rears already have a 1mm difference after another 300miles, prior to me adjusting the pressures, so given OP you have replaced all tyres, it might be worth doing the same re. Pressures and get the car checked ASAP before you chew our way through another set of rears in very few miles.
Indeed. I will be monitoring closely. I didn't have a blowout as per OP which in itself could be a nasty surprise or accident but I was spat off into the gravel at donnington on lap2 of a recent track day as a result. Obviously I should have checked condition closely before venturing out, but, having known they were fine before the drive to get there had not felt the need. Oops on my part for that
I m not saying there is anything wrong with the geo- I asked for and got track day geo, which will always be a compromise for road miles- but I will be keeping close tabs on how wear is from this point. Brings European trackers into question, which is one of the pints of owning a gt3 IMHO.
For the OP problem, as others have said, perhaps brings into question whether his car is standard or not- and further highlights to those who have knowingly deviated to keep close tabs on this inner wear which is not always obvious at a glance.
I m not saying there is anything wrong with the geo- I asked for and got track day geo, which will always be a compromise for road miles- but I will be keeping close tabs on how wear is from this point. Brings European trackers into question, which is one of the pints of owning a gt3 IMHO.
For the OP problem, as others have said, perhaps brings into question whether his car is standard or not- and further highlights to those who have knowingly deviated to keep close tabs on this inner wear which is not always obvious at a glance.
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