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Load Rating Of Tires And The 2002


gliding_serpent2

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So before i knew enough about tires, i opted for a set of (still unused) toyo r888's at cost. I opted for 185/60/13's over the 205/60/13's out due to concerns of rubbing on stock fenders (i have no interest in rolling fenders or coilovers) and at the time having no 13 inch wheels wide enough to properly run 205 tires (of course, now i have appropriate 6 wide wheels...). I know the tradeoffs with the smaller tires with respect to rolling diameter, but i did not know about the load rating of 80 (992 lbs per wheel) when i got the tires.

I searched my guts out, but likley did not use the correct buzz words, because i could not confirm the advised 2002 tire load rating (index). My memory says 82 (1047lbs). Is this correct?

Assuming 82, I played this armchair logic before, and decided that the 55lbs load difference per wheel (5.2% less load rating per tire) between 80's and 82's was inconsequential given the ability to adjust tire pressures (with lots of wiggle room to spare as toyo advises 23psi cold and 27psi hot for a 1000kg car as a starting point. Max tire pressure is 51). The only thing i figure i could expect was an essentially insignificant increase in the rate the tire would heat up to compared to the same tire with a higher load rating as i would in theory need to run higher pressures. 5% give or take, and good luck being that accurate measuring your hot tire pressures.

Thoughts and real world experience would be appreceated. I probably don't need to mention that the use for these tires will be the track.

Take home message, i think 80's should be fine for the track so long as i limit 2 wheel racing. Not as much safety headroom as 82's, but if i am that good that i can actually measure/feel the difference, or even get close to the safety limits on an 80 load index tire... I probably have bigger issues.

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Serpant, We gotsta get you back on road, they already have salt down where you are? Think about this, those awesome vintage pics of Dad racing your car, no matter what he was rollin those Toyos are twice the tyre. Modern tech on tyres puts them leaps ahead of 20 year ago issues, to say nothin of 40 year ago issues. You can thank the L words, Liability and Lawyers, sell inferior tyres in this day and age and your profits will dissapear in court cases. Run what you brung and the new Toyos will amaze you.

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I agree with DBMW2002, I would not worry about it, the BMW 2002 is a light car, even subject to the vigors or racing, would be more worried about the speed rating than the load rating, although the speed rating is a do not exceed a given speed for prolonged periods, and you are not likely to exceed even an S rated tires speed rating (112 MPH I think) for extended periods unless you are racing at Le Mans or Indianapolis, but the speed rating indicates the tire is built to withstand prolonged periods of heat and stress without breaking down, delaminating etc., so I would think you would want a tire with a speed rating towards the higher end, at least an H, or a  V rated tire.

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No speed concerns as these are v rated tires.

My coker xas are 82 load rating. Were the originals rated the same back in the day, or is this a newer phenomenon? I am thinking they were always 82 as old moulds are used for the new reissues.

Salt yes... It is everywhere. Welcome to Canada. We see salt from november till about april.

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To get my tires right i balance pressures with tire chalking. I have a system that works well. I prefer to start my pressures on the higher side as it is easier to let air out as needed, especially as the day gets hotter.

I bet you both run closer pressures than you think, but the difference is probably in the timing when you verify.

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I think I ran 28 psi hot.

But that was part of why the RA1 came back...

t

I am no expert, but my research was that the r888 was less camber sensetive than the ra1's (stiffer sidewalls in the 888) and less initial squirm due to shallower tread depth. Also, my understanding was also that many found the r888's to need less pressure than the ra1's.

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Nope, there were 2 distinct schools of thought with the 888- some ran them where Marshal said to, and others ran them softer than I did.

 

And they turned similar lap times.

 

So if you have a system that gets you grip, by all means use it.  Curious to see what you come up with!

 

t

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My coker xas are 82 load rating. Were the originals rated the same back in the day, or is this a newer phenomenon? I am thinking they were always 82 as old moulds are used for the new reissues.

I'm pretty certain you're right. The modern load index numbers, e.g., "82," didn't exist in the '60s and '70s -- I believe they were introduced in the early '80s. But if I were asked what the load rating was on a period 165HR13 XAs, ca. 1973, that 1,047 lb. number sure sounds right! I have banished all tires more than 15 years old from my house, so I don't have an example for reference. Others do!

Steve

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