Tire PSI affects steering feels?

I feel that my steering wheel a little loose at the center while driving, and I think it might be the steering coupler (or guibo so called) wore out, so I went to BMW dealer this morning to get the coupler, turned out that they had to order it and will be ready for pickup on Monday, I also tested drive the E90 335i and ended up almost bought it, after the test drive, I drove to Costco tire center and pumped the front tires up from 31 to 34 PSI and the rear from 35 to 38 PSI with hydrogen, door sticker recommends 32 and 36 PSI.

Although car feels a little bumpier after pumping up, but more joyful to drive, the key point is the center looseness of the steering wheel is gone, and the steering feels a lot tighter and crispier so that I think it may not need to replace the steering coupler anymore, car has 133k miles.

I know my car very well since I own it since new, and the symptom described above is not just something in my head, any explanation?

Of course tire pressure affects steering feel. Did you ever try to drive with a front tire that was leaking, and low on pressure?
Why do you think race teams are constantly tweaking tire pressure? It can make a big difference. If it feels better, be happy you found a cheap solution. Depending on how stiff the sidewalls are on your particular brand of tire, a bit more pressure may improve the feel of things.
BTW - I think you meant that you filled the tires with nitrogen. I don't think Costco is filling tires with explosive hydrogen gas.

Originally Posted by MJLavelle

Of course tire pressure affects steering feel. Did you ever try to drive with a front tire that was leaking, and low on pressure?
Why do you think race teams are constantly tweaking tire pressure? It can make a big difference. If it feels better, be happy you found a cheap solution. Depending on how stiff the sidewalls are on your particular brand of tire, a bit more pressure may improve the feel of things.
BTW - I think you meant that you filled the tires with nitrogen. I don't think Costco is filling tires with explosive hydrogen gas.

Sorry, correct, nitrogen.

Tire pressure (and model of tire) can make a very noticeable difference.

If the tire pressure has helped, at 133K you likely will notice the new steering coupler as well when you replace that.

First, many have a light feeling at the center...I've had it for years, but with a good alignment, the wheels stay straight. BTW, I did my steering coupler...didn't affect that play at all. I took mine out, probably later than yours, and the original one was fine. I think in many cases, that steering guibo isn't the issue.

I think part might be the rack and part is CAs and CABs...imho. That said, on the rack...I can rock my wheel back and forth maybe 1/2" at the center of steering wheel when I'm moving...it's just 'light' there and will wiggle if I move it without turning the car...so I turn another 1/4" more. Not a problem for me.

Just be careful about spending money on things you notice that are different and not necessarily a problem...otherwise you and everyone will be out of cash very quickly. Our cars are old and if you regard every change as bad, you'll go crazy too. Usually changes that are problems become worse until you get worried. If you worry a lot, you need to dial that down a bit to be with a bmw. Just saying!

Let me put this way, I know that Tire pressure would affect the steering feel, what surprised me is 3 PSI could much that much different in steering especially the play at the center of the steering wheel while driving.

Tire pressure is serious business! Std. pressure gives you a little understeer; when you increase the pressure in the front relative to the rear, you reduce it.

I run at the high side of recommended pressure in the front and in the middle pressure in the rear...and my steering is pretty neutral...add a little throttle and the rear end comes around if I want to induce a little oversteer.

Serious business is all I can say.

I always run the recommended pressure. That assures the tire will wear properly.