Why no mechanic will ever say" Im NOT SURE"

Ok I know this reaches the top of the list for STUPID questions but never the less I always get pissed off when someone who is supposed to be highly knowledgeable doesn't just say " HEy Im really not sure!" so i take my 360 in for an alignment today from a highly recommended party and while i think they did a good job the MASTER tech says hey you re tires are seriously UNDER inflated and I say ' REally I just had it a Ferrari dealer work on the car and they set the pressure on my 1 week old tires . He says No No No It says right here ON the tire 50 PSI and since i am a neophyte in this area I say ****! Why didn't the dealer know that . and he says It does not matter what it says inside the door from the car man. it depends on the tire . I know Im actually buying into this . So he says i set them at 40 back and front . Well obviously the second i get home i call the tire Co as well as 2 other respected tire places and BOTh say FOLLOW the Cars rec pressure which is 29 and 32 as we all know ..And the 50 PSI is the MAX inflation So yes i pop over to the tire place who just put them on a week ago and set em right But why the hell do people just make **** like that up .. he was thinking about putting them at 50 PSI .. That would have been sweet ..Goes to show even something as Dead Simple as tire pressure you have to ask and ask to get the facts. Sorry i had to vent a little

 

all are appropriate pressures depending on how you are using the car.

no hard right and wrong here.

on our RS car (IMSA) we used to inflate significantly over the values listed as 'max' on the tire sidewall.

the F-car values are a good 'every day' puttering around the street values - but likely not high enough for higher speed and/ or track use.

rgds,
Vincenzo

 

I can certainly see your frustration given what came down.... but golly, tire
pressure is something ANYONE can do. I'm surprised there was so much uncertainty
about it. You will never go wrong by READING THE TIRE LABEL and inflating according
to that. Might not be the most ideal for some particular driving situation, but
surely will get you in the "reasonably safe" zone.

Amazing that you got the responses you did, though.

Drive safe,


Jedi

 

I had my car in last year for a regular service and inspection for a track day, I counted on the well known garage; I was on the track day a week after,On the fist session, I found the car was very unstable and behaved unusually, I stopped and checked the tire pressure, I found all tires were at 50 psi; I lower them to the factory spec then everything was back to normal; at least I felt comfortable. I got back to the garage asking them why it was the case, they said it could be something wrong with their tire pressure gauge - lol.

 

EXactly as i would have thought thanks b

 

I know this is surreal debating tire pressure But evidently that 50 PSI Dont mean **** its max ITs a warning not a rec or suggestion. THis i what i was told when i called the Tire USA corporate number I have to think Ferrari has a pretty feel for tire pressure so for the masses Im gonna go with 29 and 32 cal me boring.. thanks b

 

Ok so you already knew what Im learning thanks b

 

Some people aren't sure where to set their tire pressures. The one thing that is certain is that the maximum inflation pressure on the sidewall is not the right one to use. The vehicle manufacturer's recommendation is always a good starting point. It will be somewhere in the car. This used to be a sticker in the driver's door jamb, but more and more it's located on the back of the gas filler door. If that fails, the information should be in the owner's manual. Sometimes, there will be a range specified, or two different recommendations, depending on load. Anywhere between these numbers should be safe.

 

wow......................................................

 

I guess you missed it sorry

The one thing that is certain is that the maximum inflation pressure on the sidewall is not the right one to use

thanks for the insight

 

I didn't miss anything, chief....not a thing, but maybe you did. i think it's time to disinflate the pressure from somewhere else other than your tires....

 

Don't different tires require different PSI? A lot of 360 owners have Michelin sports tires, so wouldn't going by the PSI on the manual be wrong?

 

I cannot say anything disparaging against mechanics, lest our resident mechanic chime in to claim superiority. All I can legally say is "mechanics are not my cup of tea".

 

You really never want to set the pressure to the MAX listed (ie. 50psi) for so many reasons, the least of being 1) Once heated up that will change by a couple of PSI, and the reality of it is your car will not handle properly, probably the rears will easilly break-loose, and tire wear is in the toilet.

You really want to look at the recommended pressures by the car manufacturer, and adjust (if needed) to your needs. I don't reccall the 360's being above 40 for any reason. I'm thinking you can go with mid-30's (32-35ish) to start with and adjust from there.

Just my personal thoughts here but the 28-30 is a bit too low and will affect the handling (delayed response due to sidewall flexing), along with excessive sidewall wear.

To each their own........ but check the owners manual or door sticker.........

 

Considering the tires were at 50psi after the first session the tires were hot when the reading was taken. Heat in the wheels and tires from hard running will jack up the pressure significantly. So considering that you set the tires to the "correct psi" based on spec information, when the tires cooled down they will lose pressure and actually be lower than what you had set them at at the track. Because heat has such a big impact on tire pressure, and the pressure specs you see on the car or in books is for cold tires, the only time to really calibrate them is before taking the car out of the garage. Its okay to add pressure or to let it out when the tires are hot, but the reading you get is only relevant to hot tire conditions.

 

I know this isn't what you want to hear, but why didn't YOU know that?
Shame on them for not knowing, shame on you for believing them. Not insinuating about your specific "expert", but you find the right jerk, for all you know they might do this on purpose.... pulling a funny on "that stupid ferrari guy". Just sayin'.

As the one behind the wheel, I think too many drivers dismiss their responsibility of knowing about even the most fundamental maintenance.
Personally, I would have heard the guy's line and just got in my car and left.

 

I know that when I would use my car (the 996/997) for an event like AutoX, I'd start off with checking the tires cold (always), then set to a number under the assumption that I will gain 2-4+ psi during the event. After each run I'd re-check as the tires would increase in pressure, and then take-air-out as needed to keep at that constant "starting pressure".
Once I reached a pressure that was just too high, you could easilly feel the car not handling properly resulting in poorer times.

Bad-news-is, obviously if you sit too long then the pressure will decrease below what you want.

Bottom line, I carry a nice large-liquid filled Longacre gauge and portable compressor always.

 

Very true but since this 'Guy" was highly recommended by a seasoned and well respected F-chatter I was giving him a bit more credibility then a stranger on the street . As evidenced by posts here Im not the only shameful driver.. Thanks

 

That's why it pays to do your own research and draw your own conclusions.

 

Thats exactly what was accomplished her .. thanks

 

Asking why a guy in a skilled profession, with stiff competition, who caters to Ferrari owners would say he's "not sure" about something is about as ridiculous as not knowing your own tire pressure....

Just sayin......

 

never go back there ...

you do an alignment at the correct tire pressure so if he thought your tires were underinflated (which they weren't) he should have put more air in before doing the alignment.

that said, for a street car the tire alignment pressure won't matter that much unless it's really low/high. if he did it at the pressure it went in at (29/32 i suppose) it is fine.

 

Chupee- Is your real original identity Husker and you got us again? This is some funny stuff.

Taz
Terry Phillips

 

Seems like each tire has different recommended pressure. This is taken from the 360 manual, fyi.
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Sorry you dont get to go to the lightning round as you didnt read the facts. So now you have to go sit in the corner.
1. I never said HE catered to Ferraris
2. He is allegedly an alignment specialist
3. I never said I DIDNT know my tire pressure either I asked which was proper to follow. Rec on DOOR or specific tire co recommendations.

Thanks for being on the show