So...this week I think I was lucky to just miss a R888R failure on an M3. Although not XBow related, I thought it might be interesting to share the pictures here.
I went to a regional track called Snetterton in a E46 M3 running well used R888R tyres. The front tyres were low on the inside edge (front is running approx 3-3.5 neg camber) but I thought it might have 1-2 track days left in it. The track is two hours away for me and since the tyres were close to legal minimum, I drove the car there and back on a different set of fronts wheels and changed to the R888R fronts at the circuit
Had a great day, first time on this circuit - the track and car turned out to be fairly aggressive on the tyres. At the end of the day I took off the front tyres to replace with the road wheels and was shocked to see the outside front tyre had an extreme radial gash with wire mesh showing underneath. The tyre was still air tight but must have been at risk of failing at any time.
My learning points from this were:
- The R888R can deceptively look like there is plenty of rubber but actually you are close to the structure/wire mesh of the tyre underneath (and maybe all tyres but I think the shape of the R888R lends itself to this)
- High neg camber cars may be more at risk where the rest of the tyre seems like there is lots of rubber left but the inner shoulder is actually very low
- Once the inner should wears significantly the tyre structural strength is compromised. Of course on closed wheeled cars it is important to keep an eye on the inner shoulder as you can't see it easily.
Anyway, not sure if the above is R888R specific or a problem for any high wear tyre. Pics attached.
