Load rating [Archive] - Team Camaro Tech

: Load rating


railing68
Oct 23rd, 09, 05:01 PM
Can a wheel with a load rating of 1520lb withstand the highest lateral g-forces generated by a summer performance radial. In other words would fail on the street?

SS

South Side Goons & Hitmen
Oct 24th, 09, 12:05 AM
Can a wheel with a load rating of 1520lb withstand the highest lateral g-forces generated by a summer performance radial. In other words would fail on the street?

SS


railing 68,

From what I remember in my years working in the auto service industry which also included mounting, balancing & selling tires until about 11 - 12 years ago when I left the business; the load rating on a radial car tire was the tire's maximum weight that it is designed to carry, at the maximum recommended air pressure by the manufacturer.

If you are looking to really slam turns and road race you will want a tire with a high speed rating. They are as follows.

- M: 81mph or 130 km/h
- N: 87 mph or 140 km/h
- P: 93 mph or 150 km/h
- Q: 99 mph or 160 km/h
- R: 106 mph or 170 km/h
- S: 112 mph or 180 km/h
- T: 118 mph or 190 km/h
- U: 124 mph or 200 km/h
- H: 130 mph or 210 km/h
- V: 149 mph or 240 km/h
- Z: in excess of 149 mph or 240 km/h plus
- W: 168 mph or 270 km/h
- Y: 186 mph or 300 km/h

If memory serves me correctly the Z speed rating debuted on the Camaro in 1989 with the 5.7L IROC-Z. When Z rated tires were introduced, there were very few street legal automobiles that were able to obtain speeds of over 149MPH. Hence, it was believed that future vehicles would be unable to be manufactured so that they could hit those break neck speeds. However, as we know now, there are many vehicles that can easily zoom past 149mph or 240 km/h for you Autobahn drivers, especially autos classified as exotic cars. This is why the W and Y ratings were eventually introduced.

IMHO, realistically you should be fine with a Z rated tire. When the ZR1 Corvette debuted 1990 it had Z rated tires and that car could rock! The Callaway Corvette of the very late 1980's started with V rated tires and then moved to Z ratings...

If you are putting for example a P245/45/17 tire on your car that will have a 1,521 lb load rating. In most cases it will have a "W" speed rating so you should be able to really slam turns hard.....Do not get fooled by some tire salesmen that would say well you never will go that fast and all you need is an S rating which is 112 MPH...Alot of the competition would try to sell against us where I worked by putting a P245/50/R16 S rating on a guy's IROC.....I would recommend a Z, V or if they were really on budget and would granny drive it no less than an H.....The reason for the high speed ratings is that it was designed with the cars suspension in mind. The higher the speed rating the stiffer the sidewall construction & the harder the tire compound which is why Ferrari's, ZR1's, Z06's aren't the best when it comes to snow even with the sophisticated traction control systems of today. BUT the exotics need the harder compound & stiffer sidewalls; which translate into higher speed ratings - in order to handle as great as they do!

In short: If you want to pull max G's put the P245/45/R17 with the W speed rating and you will be happy!! :D:D....Yea it's been a long time, but I still remember a few things or two...

P.S. Don't just take my word for it...You can go to www.tirerack.com (http://www.tirerack.com) and confirm what I said above. Good Luck! Be safe & Happy Motoring!! :thumbsup: :thumbsup:

SSG&H

railing68
Oct 24th, 09, 11:03 AM
Thanks for the reply, I was concerned with the strength of the wheel, in other words- with a radial (non-race tire) but a ultra performance summer radial, could the wheel fail from hard cornering loads. I know that some wheels are sold eg.(summit) that state not for auto-x/solo II.

I was considering a different wheel and tire combo but the load rating is only 1520 vs. my VVW V45's which are one piece 2200lb load rating.

On the street with hard cornering forces etc... could the wheel fail or what is the potential.

SS

South Side Goons & Hitmen
Oct 29th, 09, 01:42 AM
You are welcome!

Back in the day many IROC's, ZR1's, Mustangs would run in SCCA with the stock factory wheels and with some models the drivers went from 15" tire & wheels P215/65/R15 S or T rated tires to P245/50/ZR16 tires & 16" wheels. But the factory wheels on these cars could run auto-cross every weekend on oval tracks as top speed was 150 - 160 MPH with certain rear end gearing.

As far as a 1969 Camaro it's a different animal. Sure you could put a 15" Steel rally wheel and slam turns hard all day long and be ok. But you'd be running a 15" tire that is not designed for that.....I like the P245/45/R17 W or Y rated tires.

I would double check w/ companies like American Racing, Weld, Progressive Wheel Company, Boyd's, Fittapaldi etc. if the latter three are still around and see if their wheels in 2009 could handle auto-cross/ road racing like the wheels they were putting out in the 1990's. I left the auto service industry in 1998 and really haven't looked into road racing in about 15 - 16 years.

zman1969
Oct 29th, 09, 06:45 AM
I used to work for Goodyear till '90 and they used to offer Z rated 15" tires - I had a set of P24560Zr15s on my 79 T/A I absolutely loved them, the car had road huggers on it when I bought it-YUK IMO tires are really one of those -you get what you pay for-items. Wish you could still get them! anyone remember the Goodyear Wingfoots? I sold a set to a buddy with a 78 Z28 we became best friends cause of them