bwilson4web
Well-known member
Hi,
A couple of weeks ago, I went in for a recall and we got this on the drive-in, tire checker:
Now this was not enough to replace the 13k service mile tires. However, I met the technician outside and he said the tires are 'OK' but I was concerned. So I did a tire tread temperature test.
I took a small tripod and mounted a IR thermometer on it and configured the iPhone to record a video of the readings. Then on a cool day, 65F (18C), I drove 10 miles (16 km) at 75 mph (120 kph). I stopped and video recorded the tread temperatures:
I'll then start with 51 psi, measure, and then reduce by 5 psi until reaching 35 psi (yes, this is low for the rear tires.) The goal is to see if between changing the rear camber and pressure we can get even heating across all four treads.
Bob Wilson
A couple of weeks ago, I went in for a recall and we got this on the drive-in, tire checker:
Now this was not enough to replace the 13k service mile tires. However, I met the technician outside and he said the tires are 'OK' but I was concerned. So I did a tire tread temperature test.
I took a small tripod and mounted a IR thermometer on it and configured the iPhone to record a video of the readings. Then on a cool day, 65F (18C), I drove 10 miles (16 km) at 75 mph (120 kph). I stopped and video recorded the tread temperatures:
- -1.0 degrees is the normal camber spec and I had a 4-wheel alignment in December when the motor mount bolt broke.
- The nner tread is 2F (1C) warmer than the outer tread - this is the profile of too much camber and/or possibly toe (unlikely)
- 3d tread is noticeably cooler - I run maximum side-wall pressure, 51 psi, and this suggests the 3d tread may be stiff and off loaded by higher pressure on the side treads. This merits investigation.
I'll then start with 51 psi, measure, and then reduce by 5 psi until reaching 35 psi (yes, this is low for the rear tires.) The goal is to see if between changing the rear camber and pressure we can get even heating across all four treads.
Bob Wilson