Minimum tread depth for Pilot Roads

[TimXX]

I currently have a set of Pilot Roads on my bike.

The fronts have gone 10,700km and have 3.5mm left on the center tread

The rears have gone 15,500 km and have a tiny bit less than 3mm left on center. I always ride with 42 psi in both tires.

Anyway- I am going on a 6-7,000 km trip in June [TBME + visits to friends in Calif]. How long do you think these tires will last? What is the minimum tread depth one should ride at. Also- what happens with the grip of tires as they wear- lots of heat cycling, but more rubber on the road. Is the wear even over distance or does the tread wear out faster when deepest and less when near the end?

My current thinking is to put on the set of Diablo Stradas I bought [front was $25- almost free] and not worry.

Any thoughts?

TimXX

[K9XX]

Don't know about measurements....

I always go by the wear bars or radials, whichever shows first

Throw the cheap tread on there, you'll have peace of mind

[JB4XX]

The Roads go fast when near the wear bars, change them before your trip.

[Involute]

The Roads go fast when near the wear bars, change them before your trip.

:icon_imwifstupid: I don't think they will last Tim.

[FiXXation]

For what it is worth, I was just looking at the life of my last set of Pilot Roads, used on chip and sealed highways (rough and not many curves) for around town errands and speed limit touring, 42psiF/42psiR, 180lb rider. The initial tread depth was measured after the 150 mile or so "break-in", not the fresh from UPS 7mm or so before the rubber hits the road. These miles were year-round for pretty close to a calendar year (4/05 - 5/06). I also tried to avoid the wear bars when measuring. There was also some variation around the circumference of the tire, and I did not try to be exact about the measuring points from one measurement to the next.

[attachmentid=950] [Man, it was hard to get this chart in here!]

From 3 mm to end of life (past the wear bars just into the different rubber layers below the center tread grooves, but not quite to the belting fabric) was about 3000 miles (4800 Km). As the center flat spot went past the wear bars, the back tire would not hold it's line through a curve as it did earlier in it's life (I suspect because the thin part of the tire carcass did not support the sidewall as it should, letting it deform under stress too much). Also, looking at the tire after I demounted it, a larger danger would have been a quick flat from anything through the center part of the tire as there's not much there once you get past the tread rubber.

Curves would change the equation a LOT.

YMMV.

[tomek]

Change them,or you`ll have your trip ruined by tires worry.

Don`t ask me how I know this.

[TimXX]

Thank you all- I will change them before the trip. :icon_clap:

[MikeXX]

Graphed up FiXXation's data...

Trend line added by Excel (least squares, if you're a geek) which seems to show a pretty linear relation between mileage and tread (at least given the data collection method).

Sadly, my wear on Pilot Roads is nothing like this.. too much slabbing and a strong right hand