If the recommended tire pressure is 32 psi. for all four tires what would be the advantages/disadvantages of going to 29-30 or 34-35. Which way will improve handling? I usually go with what is recommended but I was wondering which way would improve handling when driving fast through a turn. Thanks.

 

under inflating would cause tire wearing, more likely to get road dmg and you would get worst traction because only the radial outer edge would be touching the ground instead of the required tire surface. Over inflation would cause the same thing, stick with the recommended tires pressure.........if you don't, it can also lead to blow outs.

 

Our car's tendency is to understeer. To help compensate for this with tire pressure, You would increase front pressure relative to rear pressure. Depending on how aggressive you drive, you can play with the pressures. I've had pretty good luck with 36 in the front and 33 in the rear.

 

you talking about 36/33 cold or hot?

 

Cold. I'm running Michelin Pilot Sport A/S 235/45-17's

 

you have Pilots? You bastard!!!!

 

In the winter, I'm always putting in air. Of course it expands in the summer and have to let some out. Run 35 p.s.i. A pound or two a month is not uncommon to lose.

 

What's the big deal? The stock TL-S tires are Pilots -- Pilot HX MXM4 Pilots, not Pilot Sports though

 

I've been running my Talon (I know, different animal) at 35psi front and 33psi rear. The door plaquard calls for 29 front and 26 rear.

The original set of tires it had (Goodyear Eagle GT+4) had a treadlife rating of 200 and lasted about 29kmiles. I ordered a set of Goodyear RSA's (treadwear rated at 240) for it and increased the pressure. That was in 1996 and those tires have 55k miles on them and can go for another 10k at this rate. The ride is a little more rough but the mileage has increased from 21/29 (stock) to 26/38. I did put on a Borla cat-back and a K&N filter and yes that accounts for some of the increase but nevertheless the tires are NOT wearing unevenly. I do check them every four months with a tread depth gauge.

 

The reason I started this thread was that I just traded my 01 TL for an 03 I35 and have the pressure set at 32/32 cold the way the sticker says. At this preesure this car does not seem to be handling the way the TL did on the same roads at the same speeds. I have Bridgestone 215/55 R17 tires and was wondering if the tires are a problem or if the pressure should be adjusted. I think these tires are sportier than the stock TL's so either it is the car or the pressure. Any thoughts? P.S. I loved my TL and other than the handling at 80 mph this car is amazing in every way so far.(1 month old).

 

O.k. here's a test you can do.

Find a piece of parking lot or better yet a concrete slab such as what an airport runway would look like.

With your tires warmed up, after you measured the pressure while cold, mash the gas from a dead stop as if you were doing a burn out for a drag race run. Look at the stripes you just made. If the width of each tire tread on the ground looks darker on the outer edges than the middle then the tires don't have enough air. If they look too dark in the middle (center of each tread) then they have too much air pressure. Thusly if they have an even darkness the full width of the tire then their fine.

 

hmm... i guess this is where mercedes "tire pressure monitoring" system comes in handy!

 

Good tip.

Here's one from my autocrossing days:
Take some chalk and mark the side of your tires. Go out an hook some corners and then take a look at the chalk. If it scrubbs off the sidewall, increase pressure until you keep the tire patch on the ground.

 

You have to remember that you're dealing with a different animal now. TL=Front wheel drive, G35 rear wheel drive. You can modulate through a corner easier with a rear wheel drive with the throttle in my opinion. Rear wheel drive is more forgiving. Try accelerating out of the corners and you'll probably come out hotter.

You probably want to start out with even front and rear tire pressures. Try increasing in 2 lb increments and see if it makes a difference. Increase front pressure relative to rear to decrease understeer.

 

"Allout" - I actually have the front drive I35 but thanks for your input. And thanks to everyone else for your suggestions. I will do some experimenting.