| Author |
Message |
Jim Schad (Jim_schad)
Intermediate Member
Username: Jim_schad
Post Number: 1363
Registered: 7-2002
| | Posted on Wednesday, June 04, 2003 - 1:25 am: | |
yeah think about it DES. Asphalt is basically REALLY hot petroleum mixed with rocks then smashed down flat to cool. Then when it gets really hot it gets gooey again. Come to texas in July and look at a parking lot. You can see tread marks in the asphalt. |
DES (Sickspeed)
Advanced Member
Username: Sickspeed
Post Number: 4420
Registered: 8-2002
| | Posted on Tuesday, June 03, 2003 - 5:28 pm: | |
quote:>at very high temps, with lots of sunshine, the track gets VERY slippery, as many of the hydrocarbons in non-concrete pavement starts to ooze outward & reduces traction
No way...! That's bugged out...! i never knew something like that could even happen... Dave, thanks, i really appreciate the detailed answer... i know if i just keep asking questions, i'll keep learning and i appreciate your contribution... There's so much to know... |
Dave (Maranelloman)
Intermediate Member
Username: Maranelloman
Post Number: 1768
Registered: 1-2002
| | Posted on Tuesday, June 03, 2003 - 5:13 pm: | |
Thanks, Bill.
DES, nothing wrong with track driving in the heat, but it does have several downsides:
>cars overheat, and oil temps go way up; that said, I was VERY impressed that my 550 did neither: water temp was right in the middle operating range, and oil temp was a relatively low 250 or so; bear in mind, this track has looooong straightaways for cooling, and I was able to use 4th & 5th gears most of the way, with only 2 short stints in 3rd each lap, such is the 550's torque
>the car has to work harder to make power, and a lot of strain/wear/use is extracted when it is this hot
>brakes get hot & stay hot much more easily, and wear faster; this is good for race cars to a point, but really puts a strain on passenger cars on street equipment
>at very high temps, with lots of sunshine, the track gets VERY slippery, as many of the hydrocarbons in non-concrete pavement starts to ooze outward & reduces traction
>tires have to work very hard, and they get greasy/slippery much faster than in cool weather
>and most importantly, driver dehydration & fatigue set in much more easily, requiring even more concentration & vision than normally.
Good question, DES; I hope I answered it for you!! |
wm hart (Whart)
Intermediate Member
Username: Whart
Post Number: 1188
Registered: 12-2001
| | Posted on Tuesday, June 03, 2003 - 4:53 pm: | |
Dave: I agree with your observations based almost entirely on street driving (although i had the 1st 550 on the track, at Watkins Glen once, and frankly don't remember what i was running then, it was, in all likelihood, the P- Zero). I have had the pirelli, the bridgestone, the michelin and the goodyear fiorano on the two 550's and the goodyear, to me, at least on the street, was the best compromise. The Michelin seemed to break away quickly under hard acceleration in the lower gears; while the p zero just sort of wiggled. The goodyear seems to stick better than the michelin but has the stiffer feel of the michelin. For what's its worth, since i don't know how many 550 owners get a chance to try out different tires. |
DES (Sickspeed)
Advanced Member
Username: Sickspeed
Post Number: 4416
Registered: 8-2002
| | Posted on Tuesday, June 03, 2003 - 4:48 pm: | |
Dave, sorry i don't have anything of value to contribute to or ask about your thread, but i do have a question with regard to your comment on not tracking a car in high temperatures... Why...?
When i first came here, i saw someone else make a similar comment and i wondered about it, then, as well...
Is it that the car may too easily overheat in temperatures whose degrees are in the triple digits or does it have something to do with the tires...? i figure the cars get hot anyway and if there's a bunch out there, the whole track is gonna be practically on fire as it is, the temperature reason doesn't really satisfy me... Just curious, i guess... Thanks... |
Dave (Maranelloman)
Intermediate Member
Username: Maranelloman
Post Number: 1767
Registered: 1-2002
| | Posted on Tuesday, June 03, 2003 - 4:09 pm: | |
My 550 was delivered new in July 2000 with Michelin MXX3 Pilot tires (not Pilot Sports). They were VERY good tires on that car, but only lasted 8,000 miles.
I replaced them with Pirelli PZero Assimetricos as an experiment, never having owned Pirelli tires before. They were very comfortable and quite grippy. During this time, I began tracking the 550, and found the Pirellis quite full of grip & very predictable, controlling some of the 550's inherent understeer. However, on the downside, they did not seem to have stiff sidewalls so they rounded/rolled over easily on track even with high pressures, and they wore VERY quickly. Bottom line: they lasted ~~6,000 miles, including a number of track sessions.
I wanted to fit the car with either Bridgstone S-03's or Kumho MX tires (nearly identical to each other), but one did not have a front fitment for me & the other didn't have the rear. So I was out of luck with both unless I wanted to get different wheels. Not gonna happen.
So, I went back to Michelin, only this time with the Pilot Sports. I did this BEFORE France got really nasty with us over Iraq, by the way. After breaking them in, I took them out this past weekend for their first track outing.
It was a 3 day event (one day corporate event & 2 day HPDE) at which I was an instructor. Unfortunately, we were beset with record temperatures each day--well over 100 degrees F., with track temps in the 120-130 range. Truly ugly.
I found that the car understeered a lot more than it did with the Pirellis at the same speeds through the tight turns. Thus, the Pilot Sports are less sticky/grippy, although, in fairness, they are still full-tread depth, and will likely get grippier as they wear a bit. However, the Pilot Sports felt stiffer! It seems that, as predicted, their sidewalls are much stiffer than the Pirellis, so they did not roll over at all.
And, they wore a helluva lot less. In fact, I put probably 350+ track miles on the car over 3 days. Since mine was the only Ferrari at the event, and everyone wanted to ride in it, I often double-dipped (going out in the Instructor group & the Advanced group as well). That, plus 120 miles each way to & from the track. With all of that, in 100+ degree heat, there is hardly any visible wear on the tires. There is some front tire feathering on the outside tread blocks, and a lot of melted rubber stuck to some treads, (much like with race tires), but no real wear. I guess that's what a 220 treadwear rating (as opposed to 140 for the Pirellis) does for you!
Hope this helps any of you wrestling with the tire issue. |
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