darth62

From what I can gather from reading this board, most of us inflate our tires a bit more than Acura recommends. I've personally been using 36 F/34 R. But, on whole, it sounds like most of us are also following Acura's recommendation of more PSI up front than in the rear. I suppose this reflects the reality that the rear wheels are mostly along for the ride in a FWD car.

I wondered what would happen if we changed the balance? From what I've read (and, I understand that I could be completely wrong), more rear wheel inflation should lead to less understeer, right? I have been wondering whether it might make sense then to change the balance - most pressure in the back, less up front.

And, yeah, I know increasing the pressure degrades ride quality. I've always though the ride on the TSX was far to stiff, but I really coulnd't care less. So, if I do something that improves handling but detracts from the ride, I'll be happy.

Thoughts?

Moderator: I did not put this thread in the "Tires and Wheels" forum because I hope we can have more of a general discussion about handling.

SacQuacker

What about the way your car handles are you trying to correct? ...If you are concerned about understeer, I'm afraid that is the nature of a FWD car. It has to do with 1) the balance of weight and 2) factory suspension set up.
The TSX is a great handling car. Frankly, I'd leave it alone unless you are planning to autocross it. A bit of understeer is considered safer than oversteer in "normal" everyday driving.
I's guess that increasing rear tire pressure could lead to oversteer if the pressure is sufficient to decrease rolling resistance or the contact patch of the tires. I'll defer on that matter to the engineers and racers of the group.

darth62

I'm not trying to "correct" anything. I'm trying to "improve" and also trying to learn about my car.

I'd agree that understeer is a FWD issue, in general, although I find that to be less of an issue with the TSX than any FWD car I've ever driven.

xizor

I've been trying out different pressures on my stock, and Kumho tires whenever I autocross, including changing pressure between runs. personally i've found that changing PSI between front and back doesn't make a whole lot difference IMO.

Logic would say to over inflate the rear tires so they have a smaller contact patch and therefore break easier preventing understeer... but I didn't find that this really made a difference. I tried higher PSI in the front and the oversteer/understeer was similar. It doesn't necessarily make sense, but vwong (a good autocrosser) said he preferred high in the front, so who knows

high PSI overall does increase handling however as it stiffens the sidewalls, but IMO and testing so far the difference between front/back doesn't change much.

darth62

Thanks for the input Xizor. Knowing this board, it was a sure bet that somebody had tried this out and examined it carefully!

BTW: If inflating a tire reduces the contact patch, was does my TSX seem to handle better with the overinflated tires? I never let the front drop below 36 PSI, but the car handles great.

Jim Holloman

Because of the stiffer sidewalls. The difference made by an increase in air pressure will generally be more noticeable on high-profile tires than on low-profile tires. I suspect that the Acura recommendation of different air pressure for front and rear (32/30) has more to do with weight distribution than with understeer/oversteer.

If I nearly always had two adults in the back seat, I would probably carry 35 PSI in all four tires during the summer and 32 PSI during the winter (lower pressure for more surface contact -- and hopefully grip). I am currently running 34/32 (front/rear) in the tires.

It is astonishing how many vehicles I see with under inflated tires. I lot of people do not realize how dangerous under inflated tires can be.

dzuy

well to be honest with you, i think that you should always run the recommended tire pressure. i mean, honda engineers spend some time figuring out WHAT to recommend.

plus on top of that, you know that tires have a maximum pressure rating right? i think mine are rated at 41 or 42 psi. just keep that in mind, just b/c you are running 36, air expands when it gets hot, so if you keep your tires too high, they will pop.

CGTSX2004

iTrader: (1)

Along the same lines as dzuy's post, you should also be careful about underinflating your tires too much. This can cause them to cup in the middle, reducing your contact patch and causing uneven wear. All things to keep in mind when you're fiddling with the tire pressures.

Of course, a couple of PSI in either direction from the recommended tire pressure won't likely be too bad.

ric

I think the combination of the design of the suspension and the vsa are designed to modify as much of the inherent understeer that front wheel drive cars have. When I first shifted from my last (front wheel drive) car, I had to reshape my driving skills just a bit, as the TSX was not nearly as devoted to understeer. I tried to find the review that spoke to the technics, and noted that Acura had modded the suspension of the TSX to compensate for inherent front drive issues as much as possible, but couldn't find it which pisses me off because it was a critical article in my leaning towards the TSX.

SacQuacker

I agree the Acura engineers have done an incredible job.