Tire questions re track please.
01-10-2008, 07:57 AM
#16
Rennlist Member
Thread Starter
What sort of events do you run and how long do you get out of a set? Nice thing is that at least they're non-directional so you can flip 'em. I'm just reading a bit up on the BFG R1's as mentioned by Anders above. Sounds like they might be even a little better than the Hoos?
01-10-2008, 08:18 AM
#17
Drifting
The 'which is better, Hoo or BFG R1' debate is still going on. Nothing definitive I've seen that points either way.
I did a test last year. Fresh (scrubbed/heat-cycled) set of Hoos and a 7 heat-cycle set of R1s (borrowed from a friend). The R1s were ~1 sec slower on a 1:27 lap. Hoos do slow as they heat cycle, but I haven't seen quite that dramatic fall-off after 7 heat cycles (maybe .5-.75 secs). The R1s supposedly last longer than Hoos but I've never verified that myself.
I usually cord a Hoosier before it becomes too hard from heat cycles, but after ~5-7 heat cycles I can feel a decrease in grip. Typically I'll use a Hoo for 3-4 races then relegate the tire to practice duty, where I'll get another 10-12 heat cycles before it cords. Careful tire management (i.e. flipping and placement on the car) is important to get full life.
Most races I run are 25-35 minutes. Hoos can feel greasy if pushed really hard after 15 or so minutes, but lap times really don't decrease that much (they just tend to slide a little more). I've run Hoos in 90 minute endurance races, and while I can't run qualifying pace the entire race without over-heating the tires, I can back off 2 seconds and the tires are fine. Usually having to slow down a little in traffic aids in tire management.
I did a test last year. Fresh (scrubbed/heat-cycled) set of Hoos and a 7 heat-cycle set of R1s (borrowed from a friend). The R1s were ~1 sec slower on a 1:27 lap. Hoos do slow as they heat cycle, but I haven't seen quite that dramatic fall-off after 7 heat cycles (maybe .5-.75 secs). The R1s supposedly last longer than Hoos but I've never verified that myself.
I usually cord a Hoosier before it becomes too hard from heat cycles, but after ~5-7 heat cycles I can feel a decrease in grip. Typically I'll use a Hoo for 3-4 races then relegate the tire to practice duty, where I'll get another 10-12 heat cycles before it cords. Careful tire management (i.e. flipping and placement on the car) is important to get full life.
Most races I run are 25-35 minutes. Hoos can feel greasy if pushed really hard after 15 or so minutes, but lap times really don't decrease that much (they just tend to slide a little more). I've run Hoos in 90 minute endurance races, and while I can't run qualifying pace the entire race without over-heating the tires, I can back off 2 seconds and the tires are fine. Usually having to slow down a little in traffic aids in tire management.
01-10-2008, 03:23 PM
#18
Rennlist Member
Thread Starter
Thanks again Jerome for some quantifiable data/feedback. Really good info. So in your opinion are these 2 tyres ahead of the similar Kumhos? I've heard that the Kumhos do suffer a bit from quality control in that it might be more likely to have issues with them than other brands of similar product? Lastly, do you bounce kerbs on these type of tyres? We have one track that I have been hitting some kerbs pretty hard on my Toyos with no perceived ill effect but I get the impression that these 'almost slicks' are a bit more delicate than the more normal Toyo, Yoko, Bridge, Dunlop etc.
PS, have you run slicks on your car and if so what are they real differences between them and what you normally run?
thx
PS, have you run slicks on your car and if so what are they real differences between them and what you normally run?
thx
01-10-2008, 03:34 PM
#19
Drifting
I think Kumho and Hankook have some new, sticky tires available but I don't have first-hand experience with either (except for the old Kumho V700 Victoracer which I will never buy again). The Hankook is supposed to be more of an auto-x tire (and comparable to the Hoo auto-x tire) so at only 4-6 laps may be OK for your use.
I had a set of the Victoracer's years ago. They were cheap, but after 2 events all 4 tires exhibited tread separation at the splice (~1/4" gap). It was a well-known issue. The Kumho engineer I communicated with said not to worry. The separation didn't get any worse and the tires were OK (reasonable grip but would get greasy in longer sessions) but I'm not inclined to buy them again when the Toyo is available.
I try to stay off of kerbs because my suspension is pretty stiff, but I haven't had any issues banging the Hoos on curbs/kerbs or gators. The tires certainly are lighter than the Toyo or Dunlop (performance advantage here) and I've heard more fragile but I've never experienced an issue (I've run through ~4 sets of them in the last couple of years). I even slid sideways across a low curb forcefully enough to knock my left rear wheel out of alignment (went way toe out and gained an extra 1.5 degrees of negative camber) with no effect on the tire (though braking from high speed for the rest of the race was somewhat interesting).
I had a set of the Victoracer's years ago. They were cheap, but after 2 events all 4 tires exhibited tread separation at the splice (~1/4" gap). It was a well-known issue. The Kumho engineer I communicated with said not to worry. The separation didn't get any worse and the tires were OK (reasonable grip but would get greasy in longer sessions) but I'm not inclined to buy them again when the Toyo is available.
I try to stay off of kerbs because my suspension is pretty stiff, but I haven't had any issues banging the Hoos on curbs/kerbs or gators. The tires certainly are lighter than the Toyo or Dunlop (performance advantage here) and I've heard more fragile but I've never experienced an issue (I've run through ~4 sets of them in the last couple of years). I even slid sideways across a low curb forcefully enough to knock my left rear wheel out of alignment (went way toe out and gained an extra 1.5 degrees of negative camber) with no effect on the tire (though braking from high speed for the rest of the race was somewhat interesting).
01-10-2008, 03:51 PM
#20
Rennlist Member
Thread Starter
What sort of weight is your car and what spring rates are you running? Mine are 616f and 708r eff. Still got the t-bars.
I figure with climbing the gators mostly it's your inside clipping the apex and the weight shift is on the outside there so shouldn't be too bad. There's one that we hit a bit head on with front rhs (our drivers side too) but the rest are fine.
This is on a short circuit of approx 1.20sec so even a second will be worth it. Longer circuit of 1.45-1.50 will be even better.
I figure with climbing the gators mostly it's your inside clipping the apex and the weight shift is on the outside there so shouldn't be too bad. There's one that we hit a bit head on with front rhs (our drivers side too) but the rest are fine.
This is on a short circuit of approx 1.20sec so even a second will be worth it. Longer circuit of 1.45-1.50 will be even better.
