Recommended tire pressures

[ledrocnoc]

What the consensus for tire pressure on this forum?

I have a C43 with the stock sizes (225/17 + 245/17), Michelin Pilots.

Txs

[neema12]

I belive its 32 and 28, but let someone who knows for sure answer. Base psi on your cars specs not the tires. For example the same tire on a miata wont need such a high psi as a boat benz.

[pnsji]

Open the driver door, and then locate a sticker that tells you the recommended tire pressure.

[ledrocnoc]

That I can do... but most of the time these pressures are a compromise, mostly for ride quality.

I was wondering what was people's experience and whether they are running the recommended pressures or changing them a bit.

[Renn 208]

Here's a repost from an earlier thread:

http://www.club202.com/forums/showthread.php?s=&threadid=5551


The ideal air pressure in your tires is primarily driven by its need to support the weight of your car and your need to maximize the contact patch when driving. The only time tire size becomes an important factor in the decision is when you use low profile tires. And at that point, people use elevated pressures to save the sidewalls, at the cost of some performance.


For max tread life, you want your tires to wear as evenly as possible... If they start to wear more on the outside edges than the middle, go with more pressure, if the middle wears out first, or your roll line's too far from the shoulder of the tire, you've got too much pressure.

The recommended pressures on your gas cap cover are the best starting point. Also, having your car aligned to factory specs (with up to +.5 camber, minor toe in up front, and conservative caster) Will aid in increased tire life.

However, the most often overlooked factor in maximizing tire life, is just the regular monitoring of your tire pressures. Get lazy, and all the effort to find the right pressure and pay for an alignment goes for nothing.

And to anticipate questions related to pressures and suspension setup:


If you want to help with tire life while still maintaining the neg camber, try to get as much positive caster as you can. That will help with keeping your tires on track. And to answer your question about suspension setups and tire pressure, I don't think that it's a simple 1 to 2 step. A statement such as "What's the correct tire pressure if I'm running H&R springs and bilstein shocks" doesn't really make sense. It's only when we discuss secondary effects of the suspension setup that we get to pressure issues.

In any case, another thing to note is that alignment specs are not something static. What you set your car to is static, but it's how the car behaves when you drive that determines how it performs, and how long your stuff lasts. For a good intro to suspension and tires go check out:

http://www.tirerack.com/tires/tiretech/tiretech.jsp

In the end, performance and longevity are a classic trade off. We all need to make compromises based on what's important to us. As one last example, having your front tires toed-out will help with crisper turn in (better for the track), but will both sacrifice straight line stability and might even switch the car from mild understeer (safer to drive) to oversteer (not so safe unless you know what you're doing). Know what your goals are, and adjust accordingly.

Given your situation (i.e. lowered car, mostly for style, want to minimize tire wear). I'd go with my original recommendation of getting your alignment specs as close to stock as possible (min neg camber to +.5 camber, spec toe in, factory psi to start and go up according to how it wears). For a regular road driver, it's really only 20% setup, and 80% taking the time to maintain.

(I've decided to repost this here, as the original content was buried in a camber/alignment thread. It should be easier to find now.)

And to answer your question, I run a few psi over stock tire pressures, primarily for high speed stability and to slightly reduce the wear on the tire edges- a hedge against my current neg camber.

[alphanumeric]

I hear when your tires are low on pressure your gas milage decreeses..but I doubt its not a great loss... anyhow.. I like to run 35-40psi.. just about any tire says 44psi max..

[NISMOPOWERED]

I would go with what the car says. I know on my Land Rover I had them set to 35 as per the tires and when I put it to 28/32 that the truck says it drove 10x better and steering improved along with the harshness. I will go check the Benz in a few.

[jnolte]

I got 19 inch Nitto 555s i run them at 44 PSI

50 is max for the tire

[fastmayte]

i put 38 front, 35 rear. found it to be the best stiffness to comfort setting. and handling, mpg's, etc

[davis449]

I run 34 all the way around, I like it.

[Abuimad]

correct me if im wrong, mercedes benz writes down the tire pressure for all cars in the gas cap on the inside, your supposed to find them there, i know mine has it

[svt ricco]

i know that you can find the right amount of pressure on the gas cap... but that is for the stock tires, remember i upgraded to a bigger size tire