Does anyone know the "correct" tyre pressures - United Bimmer Community

**ccfc1927** · 02-21-2008, 03:54 AM

I have a '92 325i on 17" alloys and I need to know the best tyre pressure. Ive been told different amounts by different garages (33fr/30r) (30fr/28r) I currently have 30fr/31r. I'd like some opinions on what other people have in similer cars please

Also another thing, has anyone ever experienced "tramlining" where the tyres follow the lines on the road as oppose to where your steering the car? If so, what could cause this to become very bad i.e. suspension componants worn etc. Ive had a look and everything looks ok with no cracked bushes etc. It's very annoying, the roads are crap where i live which doesn't help

Thanks in advance

**Dudesky** · 02-21-2008, 05:24 AM

I had the same car with the same size wheels not too long ago. Everyone will tell you different things about "correct" tire pressure. The truth is that even manufacturer's recommendations are only an average, because pressures change radically with temperature. You can be riding nicely in the morning, then be bouncing around like a rock by midday. But for what it's worth, here are my rules:

1. Don't exceed the max pressure written on the sidewalls, or the minimum pressure stated on the door jamb. Lower profile tires don't always need higher pressures- it's not an absolute; it depends on the tire composition.

2. Start with the pressures recommended on the door jamb, then adjust up by 1psi increments to get the best possible ride quality under the most common conditions. If it gets worse, back it down a little. You'll know it's right when the ride feels comfortable and the suspension feels like it's in tune.

As far as tramlining, it depends on the tire. Assuming of course, your suspension is good to go. Some will tramline worse than others. Some will resolve themselves after some wear has occured. And with many tires, an adjustment in pressure can also resolve it, so factor that in when you dial in the optimum pressure.

**ccfc1927** · 02-21-2008, 06:49 AM

Thanks, appreciate it

**denyo77** · 02-21-2008, 07:34 AM

hey, Dudesky, haven't seen you in a while

**Dudesky** · 02-21-2008, 07:50 AM

meh. I'm alive. I pop my head in once in a while. Been working 2 jobs lately and still finishing school.

nick_318is · 02-21-2008, 02:40 PM

I would go with the door jam for starters. As far as tramlining I have had it happen from time to time and I don't think its completly uncommon. I run my 17s at 35psi all around on the e30.