When to change tires

RazorRacer · 03:55 AM

My fronts have a lot of camber. So I have switched the front tires to make them last longer. Now the outsides are down to the wear bars. I have a DE this weekend (no rain forecasted) and wonder if I should burn the tires up there or change to new ones. I let the last set go until the metal showed on the edges. What is the safety limits of a radial tire?

Also, I question what I have been told. Someone said that the groves of a tire give it more grip. Is that true? I thought that the groves are just for wet conditions. Would a balding tire give more grip on a dry track?

dickster · 05:57 AM

er, not good to run down to the carcass!

yes, the groves are for displacing water in wet conditions.

fwiw a slick has more grip in the wet until aqua-planning takes over........

*edited*

masraum · 08-25-2004, 05:41 AM

If you are just at the wear bars and only on the outside then you're probably ok for this weekend, i would think. Once your tire gets down to or past the wear bars they generally have a little less grip, yes they are closer to slicks, but they are also older and have been heat cycled more which is generally bad for grip. I wouldn't put on the new tires for the DE, then you have to deal with the fact that new tires are usually more slick the first hundred or so miles, not to mention the full height tread will build more heat which is bad for tire wear and bad for the tires. I'd wear the tires out this weekend (watching them clasely, getting to the metal is too far IMO) and then put the new tires on afterwards. I would generally wear mine down until they were pretty bald, but you could still see the tread pattern, they also wore evenly. And, if I had had a freer budget I wouldn't have let them go that long, besides the crappy wet driving they didn't grip as well when that far gone.

Besides, Craig, isn't it about time you got some track wheels/tires.

Have fun this weekend!

Rich, I think his reference to more wet grip was probably because the tread helps to avoid aqua/hydroplaning until you hit higher speeds or deeper water.

dickster · 08-25-2004, 05:55 AM

sorry, i was referring to dry conditions (have edited).

Quicksilver · 08-25-2004, 06:33 AM

A bald tire gives more grip in the dry...

Until you wear through the tread rubber and get into the carcass rubber. They use a harder rubber around the belts to give the tire structure and to glue the cords together.

Watch out for tires where the tread rubber is thinner in the center. You might not notice it wearing through at first. Also the last vestiges of tread rubber can peel off which gives a quick drop in grip that feels interesting.

Wayne

David · David's Garage

Where is the DE? If it's at Motorsport Ranch, there's not much traction in the rain no matter what tire you have so it won't matter much.

RazorRacer · 08-25-2004, 11:17 AM

The DE is at Texas World Speedway.

So it's o.k. to go below the wear bar, but not expose the metal. Are there any other indicators of beyond safe limits?

sammyg2 · 08-25-2004, 12:11 PM

Some tires have harder compounds on the carcass for more stability and softer compounds on the tread for more grip. That also helps reduce chunking. If your tires were built that way and you wear down to the harder stuff it might get more slipperierer

Quicksilver · 08-25-2004, 12:25 PM

I wouldn't start a DE much below the wear bars. You are out there trying to use the tires without much safety net. Losing a tire at full-zoot is more excitement then I need.

Not sure how hard you use them and how fast they will wear. Keep a good eye on them. After the grooves are gone you are only guessing how mush rubber you have left.

Wayne

David · David's Garage

What do the DE safety requirements call for?