So yesterday was another autocross class. This time was with the local PCA and my oldest boy went with me. He brought his 2012 Mazda 3 hatch (auto) and I brought the 2009 Mini Cooper S.
We had a great time and he was thrilled to beat my time and the time his instructor got in the Mazda. It was his last run and clean, so I'm happy he beat me since it was his goal going into the day.
I was looking at the tires on the Mini today and noticed the wear looked a bit off from side to side, and wondering if it was normal or any suggestions on what to do to correct it.
Earlier this week I replaced the struts/shocks, upper mounts and spring rubbers on all 4 corners. I went with Koni Special active and parts from FCP euro. I kept the factory springs.
I know I need an alignment to get everything back to factory. My son was able to out it on the rack at work and make a quick adjustment to the front toe, but didn't have time of tools for the rear. Overall this is where things stand: the front toe is in spec, rear toe is a hair out, camber is in on the front right, 0.2 degrees positive on the left.
Tires are DWS 06+ and pressure was set to 45psi (door sticker call for 38) before the event.
Here are some photos:
left front:
Right front:
right rear (both rears look the same):
Definitely need to get the alignment squared away, but any other thoughts?
Thanks in advance
Assuming the pressures are identical, which means that your gauge is consistent, I would next consider that you won't know anything until it's aligned. That said, the difference in the shoulder wear looks like there were more and/or harder right turns.
I rotate tires every event.
In reply to Floating Doc (Forum Supporter) :
Thank you.
In hindsight, the two 180 direction changes were both right turns with one at the end of a fairly straight section, along with the two fastest corners. Left turns were in the clamshells and figure 8 crossover ( except slalom type features.
I figured the alignment might be the biggest contributor, but was curious if there was anything the experienced eyes in here might identify, such as pressures significantly too high or low.
That just looks like all season tires driven hard, to me.
Pete. (l33t FS) said:
That just looks like all season tires driven hard, to me.
I agree.
Also, that seems like Hella high pressures.
It goes for an alignment Thursday.
I may have them rotate the tires while it's there, but after having to have two give replaced when a different shop messed up the threads I'm a bit paranoid.
As for pressure, what is the guidance? Or proper way to figure out which way to go with them?
The wear pattern looks decent. Running super-high pressures like that can make sense for a car with soft suspension, not much camber gain and minimal static camber. Considering that the wear pattern suggests you may be running on the sidewalls a bit too much already on the front, I wouldn't recommend trying to lower pressures until the suspension is improved.
The only ways to tell what pressures you should be running are 1: Measuring and optimizing how much sidewall touches the ground (you could put white shoe polish on the tire shoulders next time to get a better idea) and 2: Tire temperature readings across the tread face. Racing tire temp probes cost big money, but you can piece together a K-type thermocouple probe and reader for under $100.
