Tyre to road contact patch and pressures.

[Nodster]

Hi all

Just looking at how my new tyres are running and I think, the rears may need some pressure removing, what do we think?

Looking at where they are running the fronts at 32/33psi seem correct. The rears seem too high at the same pressure. I'm now running 305's on the rear so I'm guessing book pressures don't apply. I put a clean line on with my finger to show where I think it should be reaching.

Front.

Rear.

Sponsored

 

[Proshop]

Do a burnout.. it will show your exact contact patch. If not happy lower the psi a bit and repeat!

 

[NightmareMoon]

I don't think you want to be down quite that low if you are just driving straight. Allow some room for cornering loads.

That said, dropping the rear pressures 1-2 psi should be fine.

 

[Nodster]

I've never done a burnout in my life. I'm such a virgin.

 

[Nodster]

I don't think you want to be down quite that low if you are just driving straight. Allow some room for cornering loads.

That said, dropping the rear pressures 1-2 psi should be fine.

I was thinking about trying out 30psi.

 

[Skye]

When I received my car, there were two things I was interested in:

1. How good was the factory alignment.

2. What pressure should I inflate my aftermarket rims/tires to.

https://www.miltonindustries.com/tire-tread-depth-gauge-2172

https://www.autometer.com/performance-analog-tire-pressure-gauge.html

Initially, the alignment appeared OK. And the car drove well. Still, it appeared the tires were under-inflated, using the factory 33 psi / 2.27 bar.

Using the tools referenced above, I confirmed the tires were under-inflated. I also confirmed my original tire pressure gauge, years old, was not accurate (It was a common pencil/stick type).

Every 250 miles, I began mapping tread depth, settling on 33.5 psi / 2.30 bar, cold. Since then, the tread is consistent, flat and what I read on the gauge matches the TPMS sensors perfectly.

I still check pressures before going out, due to temperature changes, but mainly for safety. I continue to review tread depth once every 250 miles.

A small PSI / bar change might not seem like much, but consider the volume of any tire, in square inches.

 

[AZlb5.0]

I run 30lbs all the way around (275/315) on the streets with no issues. 30lbs of pressure should give you a tiny bit more contact patch no big difference.

Edit: I will say that 30psi makes for a bit softer ride also.

Sponsored