Tire Choice

[joedoozer]

The track I am running has an open tire rule. Buying new tires is not an option, it's not in the budget.

I have a brand new set of SD48's for the rear (never ran). It's the spec tire at another track. I bought them a few weeks ago and never ran them.

Or

An old sort of dried out set of SD12's. These were extra tires that came with the car last year.

There is a very good amount of tread left on the 12's. I sanded them and siped them, cutting each block into 1/4's. Sipes go about 3/4 down into the tread. The track stays tacky all night and never dries out. It didn't appear to put much heat in the tires last week, when I ran the 12's unsiped.

I don't have a durometer to check them. What ones would you run?

[4bangerhotrod]

i would run the 12's and put 4 sipes in each block, you said you cut them in 1/4's so im guessing you cut the block in half across and in half around the tire making 4 sections in each block. i would put 2 sipes across the tire in each half of the block make them evenly spaced. cut them about 1/8th in deep. and if that still aint enough then put 2 sipes in each block around the tire. 1 sipe in each half of the block right in the middle of the half. making 6 sections in each small block and 24 small blocks in each big block i think that would really help you but dont cut the sipe over 1/8th inch. and maybe even shallower if you go with the sipes around the tire. if you go to deep the tire will start chunking. you could even run the 48's if you need to just put even more sipes in them. if the track is hard i love alot of sipes. just make sure when you sipe them start shallow maybe even just 3/32in deep cause you can always make them deeper but you cant make them shallower after you go to deep. if the track is abrasive or hard shallower will let the tire get heat an fire faster then wear the sipes off and keep it from getting to hot. but if its not hard or abrasive you can go deeper to put more heat in and to keep putting heat in as the race goes on, especially on a track thats hard to get heat in your tires. but whatever you do i would never start with a sipe over 1/8th in deep. sorry for the long explanation but this still is no where close to even being a fraction of the tire info you need to know to be fast.
thanks
4bangerhotrod

[joedoozer]

Good stuff, that's the kind of input I was looking for. The track is red Georgia clay and it stays wet and tacky all night. We only run qualifying and a 20 lap feature. I was afraid of putting too many cuts in the old tires, I didn't want them to start coming apart.

[dualdj1]

very good info.

also do you run plugs, or leave them open? if you aren't getting much heat make sure and foam it, and we've even run foam and a cover at times.

[pajamie]

it also wouldnt hurt to spray them with some WD-40 and wrap them up with some cheap plastic wrap to put some oil back into the rubber..

[joedoozer]

Yeah I run plugs all the time. This track is much easier to take tire temps at. Once I come off the track I immediately hit pavement. The last track I raced you drover through standing water and then the tires were covered in sand and dirt, and you needed to clean the crap off them to take a temp. It wasn't very accurate at all, you would see 30 and 40 degree swings sometimes. Or the LF is the hottest tire, because it didn't go through the water. It was pointless to even try.

What kinds of temps should I see? 150-170?

[dualdj1]

150-170 is good on soft tires, 160-185 med, 170-200 hard, in my experience at least. can go a little over on all without much troubles, but like soft don't want over 190-200, etc.

[joedoozer]

it also wouldnt hurt to spray them with some WD-40 and wrap them up with some cheap plastic wrap to put some oil back into the rubber..

I am a budget guy, so that is standard procedure for me haha. You can buy the wide plastic in the moving section at Lowe's . I use to leave them in the sun like that during the summer, but there isn't much sun left now. Can I just leave them in the garage like that to soak? Or do they need to be in the sun?

[dualdj1]

you can use a heat lamp in the garage with the same effect.