SCCA Solo C Street Discussion

[vroom4]

You will survive the season. I would go 245/40/17, as that's what beat me most of the year in CS. Could have been driving, could have been tire...but they deff weren't slower.

[Cueman]

Originally Posted by travisb

I'm getting ready to order some new tires and wheels. The car is currently stock except for front camber bolts.

I'm leaning towards 215/45 ZII and 17x7 Kosei K4R wheels. I plan on leaving these wheels and tires on Spring-Fall and switching back to stock during winter.

I have some different +42 wheels, but I also decided on 215/45 Star Specs. I have yet to drive my car at autox, but I let a couple big name guys convince me that the narrower rubber should be just as fast or faster than a wider pinched tire.

[travisb]

Originally Posted by vroom4

You will survive the season. I would go 245/40/17, as that's what beat me most of the year in CS. Could have been driving, could have been tire...but they deff weren't slower.

Originally Posted by Cueman

I have some different +42 wheels, but I also decided on 215/45 Star Specs. I have yet to drive my car at autox, but I let a couple big name guys convince me that the narrower rubber should be just as fast or faster than a wider pinched tire.

I'm wondering if I'd survive 2 seasons. I'd like to not spend $800 a year on tires.

Upping the same tire and wheel combo from 215/7 to 245/8 adds 5 pounds per corner using the weights on tirerack. I'm not sure if the extra weight is worth the potential gain in traction.

Especially since the autox runs are short and there's at least 15 minutes between runs usually, so the tires may not get up to or stay at the temp needed for best grip.

[7thgear]

Originally Posted by travisb

I'm wondering if I'd survive 2 seasons. I'd like to not spend $800 a year on tires.

Upping the same tire and wheel combo from 215/7 to 245/8 adds 5 pounds per corner using the weights on tirerack. I'm not sure if the extra weight is worth the potential gain in traction.

Especially since the autox runs are short and there's at least 15 minutes between runs usually, so the tires may not get up to or stay at the temp needed for best grip.

yes, it defies logic but that's what the top cars are winning on :/

[qoncept]

Originally Posted by travisb

I'm wondering if I'd survive 2 seasons. I'd like to not spend $800 a year on tires.

Apples to oranges, but my 245 Hankook Z214s lasted about 20 events before they corded (and grip fell off fast that day). I switched to 225 RS3s and they seem to be wearing a bit faster. Hoping for 15 events. About 2/3 on concrete.

[Briankbot]

Consider getting 225's or even 235's then. There are plenty of people who swear ultimate higher grip is faster no matter how pinched the tire.

[piknockout]

Depends on the tire, some tires like being pinched while others don't. Seems like you can get away with pinching tires that have stiff sidewalls, but softer sidewall tires don't like it. But those softer sidewall tires might be a better compound/grip. So for example, a 245 Dunlop might be okay, while a 225 Hankook might be just as good but possibly worse in a 245. It all depends. Oh the fun of street tires in stock...err, Street. :p

[Shark_Bait88]

Originally Posted by travisb

I'm wondering if I'd survive 2 seasons. I'd like to not spend $800 a year on tires.

Upping the same tire and wheel combo from 215/7 to 245/8 adds 5 pounds per corner using the weights on tirerack. I'm not sure if the extra weight is worth the potential gain in traction.

Especially since the autox runs are short and there's at least 15 minutes between runs usually, so the tires may not get up to or stay at the temp needed for best grip.

If you're looking to make the most of your money/tires, I'd recommend making the K4Rs and ZIIs your track only wheels/tires. Just swap them out, and run stocks as dailys. I have two sets of OEM wheels right now, one for daily and one for winter/autox.

[Cueman]

Originally Posted by travisb

Upping the same tire and wheel combo from 215/7 to 245/8 adds 5 pounds per corner using the weights on tirerack. I'm not sure if the extra weight is worth the potential gain in traction.

Well we're stuck with 7" wheels in street... but I considered the 225/45 vs the 215/45.

Based on Tire Rack's specs... the 225 is only 0.2" wider in tread width, but 3lbs heavier. That didn't seem worth it to me. 235/40 is actually lighter than the 225/45 and 245/40 is somehow the same weight as the 225... which makes me question Tire Rack's accuracy, but what's done is done.

[travisb]

Originally Posted by Cueman

Well we're stuck with 7" wheels in street... but I considered the 225/45 vs the 215/45.

Based on Tire Rack's specs... the 225 is only 0.2" wider in tread width, but 3lbs heavier. That didn't seem worth it to me. 235/40 is actually lighter than the 225/45 and 245/40 is somehow the same weight as the 225... which makes me question Tire Rack's accuracy, but what's done is done.

Yes, we are stuck with 7. I probably go with what I said, 215/45 ZIIs. And the 215s are almost $200 cheaper than the 235s.

The 225/45 makes 837 revs per mile.
The 235/40 makes 856 revs per mile.

More revs = smaller circumference = usually less weight

PHP Code:

Size  Tire  Weight  Revs
205/45R17  20  lbs.  862
215/40R17  22  lbs.  879
215/45R17  22  lbs.  846
225/45R17  25  lbs.  837
235/40R17  24  lbs.  856
235/45R17  25  lbs.  823
245/40R17  25  lbs.  845
245/45R17  27  lbs.  814
255/40R17  26  lbs.  836 


[vroom4]

Originally Posted by travisb

I'm wondering if I'd survive 2 seasons. I'd like to not spend $800 a year on tires.

Upping the same tire and wheel combo from 215/7 to 245/8 adds 5 pounds per corner using the weights on tirerack. I'm not sure if the extra weight is worth the potential gain in traction.

Especially since the autox runs are short and there's at least 15 minutes between runs usually, so the tires may not get up to or stay at the temp needed for best grip.

You want to drive 30,000 miles and 20 autocross events on a 200tw?

[vroom4]

Weight doesn't matter in autocross...it defies all things you read...but I almost gaurentee you that you can just as fast with a 19 pound wheel as you can with a 15 pound wheel. (or tire, or whatever)


I can never spell gaurentee right...guarantee...firefox is mad.

[Briankbot]

Originally Posted by travisb

Yes, we are stuck with 7. I probably go with what I said, 215/45 ZIIs. And the 215s are almost $200 cheaper than the 235s.

The 225/45 makes 837 revs per mile.
The 235/40 makes 856 revs per mile.

More revs = smaller circumference = usually less weight

I think a lot of consideration should be given the sidewall stiffness. I'm willing to bet that's where a lot of the extra weight comes from. Just look at the load ratings for the tire sizes...

If I am thinking about this correctly, a stiffer side wall might help maximize the contact patch during body roll with limited negative camber.

[travisb]

Originally Posted by vroom4

You want to drive 30,000 miles and 20 autocross events on a 200tw?

Yes, please. I would also like to double the horsepower by changing the air filter.

Seriously though, that is why I asked about the life expectancy of these tires. Now I know, by your statement, that getting two years is probably not going to happen.