Quick Tire ?--When Do DOT Street Legal R Compound Tires Like Kumhos Become Illegal... - The Unofficial BMW M5 Messageboard (m5board.com)

Anita · 30th July 2004, 01:03

.....for street use?

Just had a big fight with 3 or 4 guys at the tire shop (yeah, the same ones from last week). This time time after (1) saying they wouldn't change the tires 'cause they had low tread -I had called on Tues and they said no problem-the owner had said to come back again last time I was in, they were glad to do it, (2) increased the price from the phone quote and said I should go down the street if I didn't like their price, (3) remounted one of the tires backwards and complained the whole time about the job (4) manager kept taking personal calls and would walk away in mid conversation with me...well, I got HOT. After the job was done I let them have it and told them if they weren't interested in my busisness then just quit wasting my time an say so.

An employee threatened that if a cop around the corner saw my tires, I could be ticketed for not having enough tread on my tires. I have the DOT approved R compound Kumho Victor Racers. Is there a point at which they do become iilegal to drive on the street?--I'm quessing there could be different laws in different states.

Thanks for the info and allowing me to moan and complain!!! An I waiting to hear from the owner of the shop

--but I won't be going back here again.

Anita

gsfent · 30th July 2004, 01:10

Most states require about 3/32's. Old trick is to take a penny and put Lincoln's head in the tread. If you can see the top of the head, not enough tread.
Regards,
Jerry

Redshift · 30th July 2004, 01:53

If you look at something like a Hoosier road race tire, they have only a couple of thin lines of "tread" showing. They are mostly slicks. But they are DOT legal, go figure. I think as long as cord is not showing you'd be okay, but I don't know legally what they would do if you were stopped driving on the street with Hoosier road race tires

Personally it comes down to responsibility and liability for me. I do drive the Toyo RA1 on the street, but only if I have at least half tread depth remaining, and I try to only do it if its dry out and I have no other choice. It would be dangerous for not only you but also other drivers if you were driving around on slicks without tread and slipped on some standing water causing an accident.

Roy · 30th July 2004, 08:43

As stated 3/32 is the norm or until it hits the wear bars (I don't know if Kumhos have wear bars or not). but that is for the street and Highway.

RRoberts · 30th July 2004, 19:18

Lets face it. "DOT" track tires are race tires that are manufactured to minimally address U.S. DOT standards for street tires due to class rules that require DOT-legal tires. At the origins of this type of rule, street tires are what was intended. "DOT" racing tires are a good example of the technology and cost escalation that inevitably follows. Some race series now require use of a spec tire in an attempt to limit the ability of competitors to obtain an "unfair" advantage in this area. Others, such as SCCA, parse the difference between "DOT" race tires and full slicks among the various classes.

"DOT" classification is chiefly accomplished by molding manufacturer & build date into the sidewall, plus traction, wear & temperature ratings on the sidewall ! Check out the traction figure for a Hoosier dry tire, basically a slick with 2 little grooves. The stated figure is very low, as the DOT traction rating refers to wet traction. Hoosier also makes rain "DOT" race tires, that have hand-cut grooves in a softer compound, otherwise slick tire (which work amazingly well in the rain).

Despite the DOT rating, these tires are not meant for street driving and the paper label stuck to the tread says so. Tread life will be very short as well as the obvious slippery-and cold-pavement issues. Also, the tread and carcass design of a race tire is oriented to promote turn-in whereas a street tire is designed to provide greater straight-line directional stability. Drive race tires on the street and you will experience tramlining at a level you never thought possible.

Some people run Michelin Pilot Sport Cups on the street in the summer, owing to the relatively long 3000 mile tread life that can be achieved. However, these are race tires and have the same turn-in design bias. Plus they - like all race compounds - are really quite slippery when cold (i.e., below 50F). You really have to keep your hands firmly on the wheel.

When is it legal to run "DOT" race tires on the street? It depends on who you are trying to explain this to, and how motivated the officer is to respond to a reasonable argument. New tires will be problematic, and worn tires will require complete reliance on the sidewall markings. On the track, tires are discarded when the cords appear or too many heat cycles have reduced the available traction.

We all have done this a little, such as when driving to & from the alignment shop or leaving the track to buy gas. In the long run, its better to have spare wheels and a way to carry them to the track.

Regards, Dick Roberts

Anita · 1st August 2004, 22:22

Everyone, thanks for the info..and for listening to my compaints--watch out for me, I can get a bit wound up tight right before I go to track events.

Okay, I think my front Kumho's are officially corded--I can see what look like threads, still covered slightly with rubber, running around the center of my tires--are tey corded? Do certain cording patterns show improper inflation of the tires?

Dick Roberts,

Missed you on Fri. Hope you'll be back out there soon. Got to move into your run group after the first session (a story I'll tell you later--poor you) so now you'll have to contend with me out there HA HA HA

Anita