348 Still Floating !

Just changed all 4 tyres today, Pirelli P Zero Assimetrico all round, on the drive back from the fitters I took it to 100mph expecting my 'floaty' 348 to be keyed to the tarmac like a snake and it's worse than before with the old Bridgestones and without the 25mm spacers! Now I fitted the spacers before changing the tyres and it did feel more stable but on the new tyres it's gone back to how it was. Please tell me they will bed in after a period ! 1 other question, call me a dipstick if need be ,but Assimetrico's are all the same and not directional are they, in other words, the tread paterns on each side will be oposite to each other where as dirctionals will be running with the treads 'facing' the same way.
Cheers
Steve

 

I would have the geometry set up properly ,Camber,toe in,ride height,if that doesnt work it could be your suspension bushes are shot.

Andy.

 

Cheers Andy,
The problem is I don't know anyone here in Italy I can trust to set it up, the best eqipment I've seen locally is The 4 wheel lazer tracking machine at the tyre fitters! I had my BMW done on that and I know it does show camber and Toe figures but my concern is that the lads there, with the best intentions, end up making things worse, they seem ok but they have little or no experience of Ferraris.Looking at the old tyres they were worn perfectly even across the entire tread no hint of uneven wear to suggest miss alinement. Looks like I may have to take it to Roma Ferrari and have them do it. I'd better get my right arm and leg prepaired for amputation ....

 

Consider that "floatiness" could be from worn out shock absorbers (dampers).

 

All of the above, but not uncommon for new highway tires to feel loose at first. Give them some time to break-in.

 

I'm surprised to hear about your problem!

Just to eliminate the obvious possibility, have you checked the tire pressures to make sure the shop inflated them to the proper specs for the car?

I don't have the Pirellis on my 348 so I don't know exactly how they are supposed to be installed, but if you look at the sidewalls, there should be an arrow to indicate direction of rotation (if they have directional tread) and there should be an "inside" marking if it matters which side goes inside and which goes outside.

Please keep us posted on what you find!

 

Many 348s were raised a little to clear driveways, etc. When they are stock and especially when raised, they tend to gather air in front and wander around. No tire made will help that. Consider a splitter somewhat like those on the SS models. They don't look like much, but they lower the leading edge of the car to the bottom of the spoiler instead of the top of the bumper, moving just enough air to stabilize the front end. I fabbed a little 1" splitter for mine and it made a world of difference at speed.

 

If you want to sell your 25 mm spacers let me know, I'll buy them.

Looking for 15 mm front spacers also. If I can't find used I'll buy new.

Rodney Dickman

 

What are the tire pressures set at? Some installers will air them up too much causing you to ride on the centers of the tread, vastly reducing contact patch. Worth a look.

 

When we speak of setting up the geometry properly on these cars, is it to factory specifications (later ones that Ferrari recommended for these cars) or to driving style? i.e., if one does a lot of tracking, or mostly drving around town and some mountain road driving. Or is it mostly trial and error. The other thing is that a competent alignment shop needs to do this who is familiar with these cars, specifically the 348?

 

The Pirelli's take at least 250 miles to bed in.

 

Have you had a weighted 4 wheel alignment done?

 

What is with all the troubleshooting talk on this thread

The solution is very clear :

"Replace the 348 with any 355"

 

You're the track man, but my own Pirelli tires bed-in with fewer than 10 miles on them new, if that datapoint is worth anything.


Sf348s, here's the basic list of things to check for handling problems on a 348: http://www.the348.com/tech/348.html#Handling

 

Since he and the car are in Italy........wouldn't a drive to Maranello be able to get the thing straight?

 

...depends on the roads!

Ba dump bump.

 

I have a GTC with 18" so I guess the tyres are slightly different and I run directionales on the front, but mine were "squirelly" for quite some time and felt like they were falling over themselves. After about 250 miles the grip levels went through the roof and the car stabilised.

Reading more of this thread I would also suspect shock absorbers.

 

You should not have a squirly car. Bedding i tires is B.S.! Your chassis set-up is off. Get it corrected. Start by taking the car to a race shop not a tire store. They know how to set-up the suspensions. Your problem can be as simple as too little front caster or mismatched caster and improper rear toe. these are are highly tuneable and therefore easy to screw up. I can tune my 348 racecar for perfect balance at speed with mismatched frot to rear tire brands! You just need to know what you are doing. I only use a set of strings and laser level and corner weights. Presto home alignement. Don't laugh racers have been doing this for decades. Don't be fooled by fancy equipment that techs don't know how to use.

 

There is nothing wrong with the alignment on my car. Seeing as you're trotting out the expletives IMHO that is "BS" too, it's happened to every single new set of tyres I've owned across over 20 cars and there are numerous websites confirming this is due to the molding process - ie from a tyre website:

"It may sound like an odd concept, but if you buy brand new tyres and slap them on your car, then try to drive the nuts off it, you're going to come a cropper.

The reason, believe it or not, is that all tyres need a running-in (or scrubbing-in) period. When tyres are made, they're typically injection-moulded in a heat press. In order to get the tyres out of the mould, it is first lined with a non-stick coating. When the tyres pop out, some of that releasing agent sticks to the tyres themselves.

What you get is a nice shiny new tyre, with 'shiny' being the operative word. The releasing agent can take as much as 500 miles to scrub off.

Now for the everyday Joe, this isn't really so much of an issue, but for people who are fast drivers, or think they're fast drivers, this can lead to a distressing loss-of-grip mid-corner and a visit to something large and solid. It's doubly important for motorcyclists because they have half the number of tyres and a much smaller contact patch per tyre to boot."

 

I have never experienced a tire break-in period although I have heard of that.

You have issues with your suspension if a new set of tires does not feel right. Alignment is not going to help that.

It's possible you have damper (as suggested) or bushing issues-sway bar, etc.

It sounds like you are experiencing a mechanical disfunction.

 

Hmmm, agreed sounds like more than tire issues. The 348 is somewhat flighty anyway. Sounds like a good alignment and set-up maybe in order if nothing mechanical is out.

 

Now you are really pushing the BS! The amount the releasing agent effects tire grip is minimal. You are not a fast driver if it takes 500 miles to get the agent off. I am not a fast race driver but even I can run a new set of street tires to the cords w/ 1-2 track days, slicks even faster. You can bed-in tires very quickly. Perhaps if you are M Schmacher you can feel some subtle difference. If you are that good then you could feel the day to day changes in tire squirm from tire block wear too. Any difference this driver is feeling is not tire but due to mechanical faults like bushings/shocks or alignement/chassis rake set-up issues. 90% of dumb alignment shop pros think 4 wheel alignment when they get to the rear of a car is a camber adjustment! Don't take my word for it ask them what your alignment guy is actually adjusting when he does a 4 wheel alignment. Almost none of these guys start by marking the chassis centerline. I am not making this up.

 

FBB -- any shops you recommend for aligning my 348, I would appreciate the help. I live in Southen California area, specifically Glendale/Burbank area.

Thanks, Armen

 

If I was not doing it myself the only guy I would use is Darrin Nishimura of WestEnd Alignment in Gardena Calif. He is the best and worth the drive if you are serious. But if you want it done right you will have to spend time. He will make you sit in the car as he aligns so bring a paperback book with you. It takes about 1/2 day to corner weight and align my race car with me sitting in the car with all my race gear! I'm balanced exactly. I have seen the scaling computer this guy is good. Nobody does alignment like Darrin. 310-808-9233. In 30 years of doing cars I have not met anyone better.