| Author |
Message |
Mitch Alsup (Mitch_alsup)
Member
Username: Mitch_alsup
Post Number: 529
Registered: 4-2002
| | Posted on Friday, April 18, 2003 - 10:31 am: | |
Let's see: 3800 lb car, CoG 20" above road surface, 100" Wheelbase, 1Gs of braking;
This would transfer 760 lbs to the front tires above their static load (380 lb/tire).
If the car has 50%:50% weight distribution originally, 3800/2/2 -> 950 lb/tire
950+380 = 1330 lbs braking load on front
same senario except that we are in pure cornering: 3800 lbs, 20" CoG, 57" track, 1 Gs cornering.
This transfers ~1300 to the outside tires, or 650/tire.
950+650 -> 1600 lbs load on outside tires in a 1G turn.
I can see why you need a 99 tire load index. |
syd (500syd)
New member
Username: 500syd
Post Number: 9
Registered: 3-2003
| | Posted on Friday, April 18, 2003 - 5:30 am: | |
Pirelli have advised me that there are *no* R compound front tyres with the required load rating for a 550. The only rears that meet the requirement is the P Zero C. |
Barry Wolinsky (308gtb)
Member
Username: 308gtb
Post Number: 479
Registered: 2-2002
| | Posted on Monday, April 07, 2003 - 8:44 am: | |
Syd,
Tire Rack's website has an informative page on the subject:
http://www.tirerack.com/tires/tiretech/general/speed.htm
Barry |
syd (500syd)
New member
Username: 500syd
Post Number: 8
Registered: 3-2003
| | Posted on Sunday, April 06, 2003 - 9:45 pm: | |
Hi Barry,
I can't find any load ratings on the Hoosier web site. Maybe you've found a page that I couldn't. |
Barry Wolinsky (308gtb)
Member
Username: 308gtb
Post Number: 478
Registered: 2-2002
| | Posted on Sunday, April 06, 2003 - 6:20 pm: | |
Hoosiers are racing tires. Check their website for for information on load ratings.
http://www.hoosiertire.com/
|
syd (500syd)
New member
Username: 500syd
Post Number: 6
Registered: 3-2003
| | Posted on Sunday, April 06, 2003 - 3:06 am: | |
In looking for R compound tyres for my 550, the factory minimum rear tire load index is 99=1709lbs=775kg. The front load rating is 95=1521lbs=690kg.
Coincidentally, the 360 Modena has a similar load rating for the rears, and 89=1279lbs=580kg for the fronts.
Now here's the problem, the PZero Corsa have a load rating of 93 and 88 (rears/fronts)
http://www.tirerack.com/tires/Spec.jsp?make=Pirelli&model=PZero+Corsa
The Michelin Pilot Sport Cup have a load rating of 94 and 88
http://www.tirerack.com/tires/Spec.jsp?make=Michelin&model=Pilot+Sport+Cup
This means that neither tyre brands would meet the minimum load rating for the 360 or 550.
In the US or UK, if you had these tyres on your car, would the car be 'not roadworthy' such that if you had an accident on the way to the track (or if you used these tyres as your everyday tire), the insurance company could deny the claim because your car is not meeting the manufacturer's specs?
If you ran the tyres on the track, would they be 'dangerous'? The load rating for the rears in particular is significantly lower than the manufacturer's minimum.
Also, does anyone know what the Hoosier's load rating is? I can't find it on the web. |