[Ph0zenstone]

How many heat cycles can a set of BF Goodrich R1 slicks last? I'm thinking of getting a set of used 245/40/18 for my oem 189's (non staggered). The tires have been through 4 heat cycles, is it worth it to buy them used now? I will use them mainly for autocross, how many more auto'xing events will i last with these?

[jbass524]

Originally Posted by TrackRat

I and several people that I know of with Bimmers have used the BFG R1s for 18+ track heat cylces. Auto-X is not likely to get them as hot and obviously not for as long so they should last you a long time IMO.

Is that days or sessions?

[jbass524]

Even though I don't use these or any Rs this is super helpful for track folk. I use Direzzas and I think this is similar for me with these tires and my driving style.

I only have my very idiotic, "they feel slippery", assessment. It sounds like seat of the pants assessment of grip is the only way to measure this? I'm sure there are many who don't really know what to look for or trust their sensibility, especially with street tires. Wear bars aren't how you measure your tires life; at least for me.

I know I did at least 4 days with heat cycled tires last year as I was on my 30th - 50th session on the same tires. My driving improved so I was still going as fast or faster but I kept telling myself that the tires feel shot.

[Ph0zenstone]

Here are some pics of the tread remaining. I picked them up for $500. I see them for sale on discounttiredirect for about $250 a peice. is that a good deal judging from the pics?

[jbass524]

Originally Posted by TrackRat

The longer you drive the better you tend to get at judging how the car feels because you have time to assess the car not just drive the line. Most street tires and even race tires can be over heated when driven at the limit for a period of time. Street tires tend to drop off more than pure track tires when over heated. Both feel "greasy" or slippery when over heated. Changes in tire pressures can also make a tire "fall off" during a run session.

Personally I think many people use heat cycles to justify the purchase of new gumballs.

I agree but I'm not one who has extra rubber money peaking out from under my mattress so I like to get as much out of them as possible. Unfortunately, this had me driving 16 to 20 sessions with, what felt like bricks for tires at points.

I definitely feel the precarious edge of grip get closer and closer as I move through the session then at about lap 5 they're hot and greasy.

Back in the paddock I reduce tire pressure to my preferred at full hot. This happens as I always seem to be chasing the right pressure by reducing it through the day.

Anyway, nothing like the first 3 laps with good tires and good pressure.

Maybe it's time for me to try Rs.

With all of this said, is taking the ambient temp, track, driving style, tire feel, tread wear and tire age (# of sessions) into account the best way to assess your tire's condition?

[jbass524]

Originally Posted by TrackRat

I was just jesting about buying new rubber.

Other than lap times the only practical means to assess a tire's useful life is by the driver's impression on the track. When a tire falls off it's not like the car falls off the track per se, it just loses some grip. Heat cycles are just a convenient reference point to try and judge when the fall off typically happens.

As a side note a number of BMW owners that I know who do numerous HPDE events per year actually buy a spare set of wheels and R1's or similar "slick" tires because they get better wear and thus value than using treaded track tires. Everyone's situation is different.

I know you were kidding but it's true

Yeah. This is how I assess my tires but I'm not great at it. I do have track wheels I just choose to use Direzzas because I wanted to get good enough to understand why my car might break loose and be able assess when it will break loose before I moved to Rs. Next set of track tires is going to be Rs: Nittos or Toyo. We'll see.

Thanks for your information.

[S4to335]

I cant remember how many heat cycles it takes me...its not as long as I would hope. I usually ruin the outside edge of my tires..since I dont have enough negative camber.