Hi, I changed the 2 rear tyres of my 348, (after I hit a cornerstone real bad) and now the road holding of the car is really terrible. We checked the car for other damage, but there was nothing to see, the rims where ok also. Dealer said the reason is because I didn't change the front tyres as well, he says a 348 always need 4 new tyres, when tyre changing. Anyone has experience with this ...
There is another thread on this subject and it confirms that you can have this problem when you change only two tires. Not related to handling, but make sure the tires are mounted on the correct wheel. Each wheel is different on the 348.
Coincidentally, I just spent an evening with a Porsche 928 enthusiast and we got talking about the tyres on my 348 which were due for a change. He said to make sure that the Tyre Dealer has got the suitable tyre fitting rig. He said that the standard KwikFit tyre shop rigs aren't suitable for tyres of the 348 dimensions and that the result is a twisted and possibly even damage tyre whose bead doesn't seat correctly on the hump. This may be a cock-and-bull story but when I then took my tyres along to the Ferrari main dealer a day later to get them fitted there, he said they need at least 1 1/2 hours to do as it takes that long to get them correctly seated, balanced and road-tested.
I sort of am amazed that there are this many people having issue just replacing rear tires. I have changed my rears twice since putting on my BFGoodrich KD/TA's and havent seen an issue at all with the car losing the backend either on the track or street. In fact I have never head of this type of issue on a street car at all as in most cases there are few people replace all their tread at once.
??? 1 1/2 hours? My tire place mounted mine in about 15 minutes. Changing all 4 tires is probably the best way to go. Had similar problems until I changed out the fronts as well. Check out this thread. http://www.ferrarichat.com/forum/showthread.php?t=36922#goto_threadtools
Don't mean to change the subject but, Hey "Jjstecher" are those Sparco seats in your 348? (looked at your profile)
Ahh! but they were tires, not tyres! LOL! Seriously, though, I'm much more at ease with a dealer who takes his time! I reckon: - putting the car on a lift, - raising it, - removing the lugs without an air wrench, - mounting the wheels on the tyre machine, - removing tyre and valve, - fitting new valve, - checking wheel condition, - fitting tyre, - centering the high spots on wheel and tyre, - balancing the wheel/tyre, - refitting on car, - tightening lugs with torque wrench, - lowering car, - short test drive within an average of 4 minutes per wheel is just a bit too hasty for my liking! Maybe I'm just gettin' old!
Thats scrap. I have just always only changed two tyres usually the rears and never had a handling problem. I hear some many 348 owners having this problem. I have never come across this problem. Must of of sorted the problem out on the spider the last of the 348 models.
Your dealer is correct, nine times out of ten you will have to replace all four tyres otherwise you will experience handling problems. I assume that you have had the steering geometery checked.
This is not true.........I have personally changed "only" the rear tires on several high performance exotic cars other than 348's with no adverse effects whatsoever. To wit....Lambo's & 911's have significantly more HP than 348's.....and totally different handling characteristics that are already much more dramatic than a 348, even with 4 new tires that were installed at the same time.........and they eat two sets of rears for every set of fronts. If the front tires have more than 50% tread remaining and no signs of cupping or other abnormal wear patterns you will be all right provided that the new rear tires are of the same brand, model, designation, tread pattern and composition as the fronts.....in other words.......exact duplicates for what was on the car. Anything else can create handling issues. Also.........new tires are green and require 2-300 kms of use and heat cycles before they reach their potential. The problem here is that a Michelin Pilot Sport or Pirelli P-Zero or any other tire can have several different variants within the brand name specification..........and if a later model or earlier model tire with a slight change in the tread pattern or internal composition was installed, you may have handling nuances.....but visibly from the outside when you looked at the tire, or the 17 year old apprentice grease monkey in the tire store did, you guys wouldnt see anything to make you think otherwise. It's happened to me before........... Tire manufacturer's change their product often.....but the name remains the same.....when in fact the tire that is branded "Super Sticky Gumball 3000" on the sidewall could be noticeably different internally or on the tread pattern than last year's model.......and most tire shop guys don't have a clue about this......let alone mounting and balancing them properly on the correct wheels and in the proper direction to begin with. When you ask for tires to match the fronts make sure of the production date......and check with the manufacturer directly as to whether or not the tires they are trying to sell you are in fact identical as to what you have on your car now. The brand name is only 1/2 of the equation and does not mean anything.
They are OMP's and I had to get them because I am to damn tall to fit in the car by default and it made track time more comfortable as you slide around a lot less.
Do they sit lower in the cab than the stock seats? I've got a set of brand new Corbeaus that I bought for my 308 a couple of years ago, but they sat too high so I took them out. Wonder if they'd be too tall in the 348?
You can bolt them to the floor if you want but you should be easily able to get the stock Corbeaus setup under the seat and still have room as this is what I did with the OMP ones I have. If I need to lose weight for the track I just bolt the seats to the floor. John
