Hello all Driving my F12 from So Cal to Cavallino my tire blew in the middle of nowhere Louisiana. Ferrari had to tow me back to Houston. My question is regarding the tire. They were 10 months old w 6K miles. I did not hit anything. The interior wall of the tire just gave. This was verified bye Ferrari of Houston. I was keeping an eye on the tire pressure & temp. They both would clime during my drive. I remember that the pressure would range from 38 to 40 after a few hours of driving. Does this seem reasonable? Thanks for the insight Image Unavailable, Please Login
I see those same pressures on my F12 also, both pressure and temp will climb while driving, perfectly normal. Glad you didn't have an accident!
sorry to hear this. i have the same car and same tires. i run psi in mid to lower 30s but around 38-40 shouldn't make a tire blow by itself
Those are very high pressures, anything above 36psi is excessive and actually results in the middle of the tire bulging so your contact patch is reduced. Look at the max pressure on the sidewall, probably 51psi. That alone will not cause the interior-sidewall failure, but, if you had a lot of negative camber that would definitely cause the interior to wear down and 6K miles is about as far as it would go before failing. If the tire had a more relaxed camber and no damage visible (dismount the tire and review) then I would file a claim with Michelin, they should replace the tire as being defective. See first page or so here for some Michelin contacts https://www.michelinb2b.com/wps/b2bcontent/PDF/Warranty_Claim_Procedure_manual.pdf
This. If you start the day in the 50-60F range at the recommended 32-33 psi, getting to 38-40 psi when the tires are 110F plus is normal.
That would be a 'normal result' that results in excessive tire pressure. If it is raining then having the tires at 36psi is good as it keeps the treads at maximum spread (to channel water) without reducing contact patch. Otherwise, tires should be about 80F+ over ambient temperature when fully warmed in dry conditions.
Tire maker pressure recommendations are always cold temp, even the max tire pressure. The max psi that Michelin PS4 is rated for is 50, but then tack on up to 15 psi and you are still in the operating range. The OP at 38-40 PSI is hardly excessive. 80F+ over ambient is highly dependent on factors such as speed, road conditions, and driving style. If I’m putting around town I am never going to hit 80 over ambient and if I am at the track the only thing I care about is uniformity of temp across the tread surface, regardless of temperature reading.
Sorry, I was unclear, 80F+ from ambient is surface temp of the tire at full warm, not the air within the tire. anything over 36psi is excessive (70% of max psi in the case the Michelin tire being referenced), a significant reason is that your contact patch shrinks as the tire "balls up" and starts tippy-toeing as it bulges in the center If you had that tire at 65psi (50+15 you mention) it would explode off the rim (tire bead would not hold), not sure where you are getting your ideas from, but please be careful what you suggest. you might want to read through this https://blog.firestonecompleteautocare.com/tires/what-if-you-overinflate-car-tires/
I am simply pointing out that 50 psi is a cold temp. Driving the tire at the max psi will increase the pressure therefore the 50+whatever is a normal increase will still be operational. Not recommended but operational, I would add. I’m sorry to be blunt but you are incorrect. A tire will not explode off the rim at 65psi. Not even remotely close to accurate. You would have to go beyond the limits of most compressors to blow up a modern car tire such as this. I’m not sure why you are differentiating the air temp in the tire from the surface temp of the tire when they are highly correlated and the only measurement that is meaningful is tire temp, surface or otherwise. Expect a 50 degree increase in tire temperature over ambient air temperature after 30 minutes of highway speed driving. The OP was within the normal range for this tire based on conditions. There was nothing excessive about it.
38psi is excessive, tire patch shrinks as a result, you want to use all of your tire, not less of it... if you have that brand/model tire at 65psi and drive around at highways speeds for 2 hours and make it out alive I will be very impressed, very, especially if it is raining, I wonder how balled up the tire will be riding on a lot less surface area of the tire so burst pressure could be 200psi (looked it up), that's a lot more than 65psi, but the tire will be quite stressed and definitely sub-optimally functioning and if you were to hit a surface imperfection at speed the car could certainly bounce a lot and potentially cause loss of control temperature, simple, because you externally measure the tire temperature to see how it is functioning, that's what you monitor, not the gas temperature inside (which, could be, for instance, nitrogen, which is not going to heat as easily as 'air' so the gas temperature is not very useful 'in general' as the tire external temperature) when that Michelin tire exceeds 36psi its tire patch starts to shrink as the pressure begins to deform the tire and it will start to use less of its potential surface area and for a performance car that's not good and that's my main point
I set mine at factory level in April with air temp about 68F. Coming back from the dealer today at 94F all four reading 40 lbs. on the dash. Normal rise. Check with Michelin on your tire failure. Bad tire if no road hazard.
Thanks for the info. Ferrari of Houston is telling me that Michelin will simply claim tire was out of alignment. I was crushing interstate 10 for over a thousand miles at 90plus at times and never noticed any issues w alignment.
Any chance you bought the tire from tire rack? I just had a sidewall issue from a pothole and realized they include their "protection plan" for 2 years with most purchases. Tires were about a year old and they wrote me a check for $307 (this is for my bmw)
My experience is you were not ruining the tires too high with pressure, maybe it was a little bit too high? But not dangerously so. Ive done the same as you, for longer, at higher speeds (in other countries where it was permitted) in an F12b actually, and never had a problem. Tire was MPSS (4S predecessor). I note the tire temps and pressures often do as you reported on all sorts of drives I go on. Never had a failure like this. It seems to me you just had a bad/ defective tire. I would see about filing a claim with Michelin. In the past I had a tire that just had a weird looking side wall after a year- I cant explain it, it had these weird ripples, and they replaced it and its corresponding other side tire, I had about 2k miles on them. It was over a decade ago, but, you never know unless you ask. Sent from my iPad using FerrariChat
Likely due to manufacturing defect. It not uncommon for factory recommendation psi to be in the 40's, ie, I've seen AMG recommending cold pressure in the low 50's for max load at high speed of 300kph. So I highly doubt pressure in the upper 30's or 40's will cause a non defective quality tire to explode.
What was your cold pressure set at? 38-40 is a bit high for hot pressure, but not alarmingly so. Off of the top of my head, I recall that the max pressure rating for that tyre is 51 PSI. Now that is obviously way past what it should ever be at, just saying that 38-40 PSI is not the reason for a blowout. 38-40 PSI can easily be reached if you push a bit on twisty roads. Something else was going on here. Faulty tyre, tyre damaged during installation etc. I will say this, and I have said it before. When running the MPS4S on the F12, it is a good idea to step up to a 265. The OE MPSS had a very wide for a 255, and that helped keep temps down. Now the 255 MPS4S has a narrower tread, and thus it will run hotter. By running the 265 you are running a tyre that is much more similar to the OE from a tread patch size view. Yes the diameter is a tiny bit bigger and the tyre carcass is a little wider, but overall the 265 is a muvh better fit. Get them to replace both fronts with 265's and drop cold pressure 1 PSI from OE spec due to the slight increase in volume. Sent from my SM-G930F using FerrariChat.com mobile app
i just blew 2 front right PS4Sin one month. https://www.ferrarichat.com/forum/threads/ferrari-wheels-made-of-butter.637708/page-2#post-147913929
Quite possibly you hit a small pothole weeks before and got a small sidewalk bubble from sidewall damage which went unnoticed until it blew. That being said some tires do have manufacturing defects that pass inspection. Short of xraying each and every tire hard to catch but if I were planning high speed runs I would inspect visually each tire and wheel carefully in addition to manually checking pressure s and not rely on the cars digital read out Sent from my iPhone using FerrariChat
Ferrari of Houston let me know the inner tread was worn down to the cords caused by the alignment being out of specifications. The toe setting was way out. The pressure was not the issue