S4Heaven

For all who have change to different tires than the stock ones, which tire pressure do you use. Would u still use the pressure recommended by the factory (aka inside the fuel door) or do you use a different pressure since the tires are of a different manufacturer?

I've just swapped on my 'winter' tires, 225/45R17 Michelin XGT H4 so that I can drive in wet + snowy conditions for this winter. I'm not sure what tire pressure to keep them at. I didn't get real snow tires since in the Bay area, we encountered snow only in the mtns. so I needed all-around good tires to use.

Any advice would be appreciated.

Dave G

the pressures aren't so low that your wheels get dented or otherwise damaged by potholes.

You may hear from some of the tire pressure ***** (most of them frequent the Wheel&Tire forum, not the S4 board) who will tell you to go with the low numbers that Audi recommends, such as 32psi or 34psi, or some other crazy low pressures. As it turns out, several of the tire pressure ***** don't even have cars with low profile tires like ours.

Again, be advised that low tire pressures may result in dented or damaged wheels if you hit potholes.

After saying that, I would suggest that you start at something reasonable, in the mid-30's psi, but anticipate that you may need to go up to 40psi+, and maybe even 42psi. It may depend on how soft the tire sidewalls are. The softer sidewall tires may require some extra pressure.
I don't think I've seen anybody use more than 44psi on any tires in the stock size 225/45-17.

If you took a poll, you'd probably find that the average pressures used by AudiWorld S4 folks is in the 38psi-40psi range.

Since I tend to beat a dead horse, I want to comment on high vs low pressure again. Low tire pressures not only can result in damaged wheels, but its also a potential safety risk. "High" tire pressures are rarely a problem (obviously it depends on how high).
Look at the warnings on tires. The warnings are for under-inflation and overloading; NOT for over-inflation.

Good luck.

muppco

The factory recommended pressures are generally tuned more for ride and even tread wear under moderate driving conditions. A few extra lbs will help reduce the fronts from rolling over as much during hard cornering and can give a crisper response to steering inputs. The down side of higher pressures is premature wear of the center of the tread. The idea is to try to find the pressures that will give you the best balance between handling, cornering grip and reasonable tire wear for your own particular driving style.

GrandPaJohn

Another good "rule of thumb"....it's better to have too much pressure than too little.

BSOD

I've recently switched to winter tires (dunlop M2's) in stock size on stock rims, and they're currently at 40psi, and feel a bit floaty. I'm not sure if it's just the pressure, or if it's just the lesser grip of these compared to the stock RE040's. Planning to hit some twisteez tomorrow, and see how they feel, maybe lower a psi or two to see if that helps.

Dave G

I've used pressures from 38psi to 43psi in the M2 winter tires. I prefer something in the 39-40psi range, for the best balance between rim protection, ride quality, and handling. However, I must say that I really don't push the car in turns (on dry pavement) while I have the M2's mounted. Its not because the M2's can't do OK; its just because I don't want to prematurely wear them out.

Dave G

Thanks John. Well said.

Dave G

so I'll bet that the greater wear in the center of the tread (from higher pressures) will even out with the edges/shoulder areas of the tires.
Its always worked out well for me.

I don't think I've ever gotten less than 35,000 miles out of any of my tires (except winter tires), even ones with 160 treadwear ratings; although it looks like the stock RE040's may only last 15K-20K miles.