First DE event, what a lesson!

Bags · 04-28-2002, 06:03 PM

I just finished my first DE event at Putnam Park near Cloverdale IN. Hats off to the CIR PCA group that organized and admisistered a wonderful weekend. Saturday was pouring rain and 45 degrees and I quickle found out what throttle on oversteer was all about!!(more than once) It felt like ice but what an excellent chance to learn the characteristics of my car in adverse conditions. Sunday was 46 degrees, 30mph winds but dry. Boy was it fun to drive and drive hard. I had spent time, had lots of fun and some $ fixing my 87 Carerra with turbo tie rods, strut brace, Bilsein Sport shocks, 22/29 Tbars, adjustable spring plates and SSI/sport exhaust. I quickly learned the car had more power than I could handle at my feeble skills and abilities. I was humbled and impressed. The weekest link, other than the driver, was my tires. It came with "Somotomo" tires on 17"cup wheels. These tires had a hardness of 220 and gave no warning before letting go. So, I am looking for a good performance street tire that I can track, until another set of rims and tires becomes a reality. Opinions???
Thanks

john_colasante · 04-28-2002, 06:34 PM

Kuhmos

old_skul · 04-28-2002, 08:15 PM

Kuhmos are nice. Very good bang for the buck.

I use Yokohama AVS Sports. They're expensive but worthwhile, I suppose. I think the AVS Intermediates probably provide about 90% of the performance at half the price, though.

Get a good, reputable soft-compound tire. That's all.

old_skul · 04-28-2002, 08:18 PM

And by the way, what turn did you find yourself losing the rear end in? I lost it in Dead Bear - twice - and got a little squirellly in the hairpin (7). It's a fun track in the rain because everything happens in slo-mo and you'll really learn to handle your car in the wet.

I was there last October - got one (!) dry run in.

89911 · 04-28-2002, 08:31 PM

Quote:

Originally posted by Bags
I The weekest link, other than the driver, was my tires. It came with "Somotomo" tires on 17"cup wheels. These tires had a hardness of 220 and gave no warning before letting go. So, I am looking for a good performance street tire that I can track, until another set of rims and tires becomes a reality. Opinions???
Thanks

I am not sure what your statement means. The 220 is most likely the wear rating, not the hardness. For a street tire, that is getting low, so these tires are not excessively hard . As far as warning before letting go, hard tires by there nature, generally give plenty of scrub noise or squeal when breaking loose. Softer compound tires will give less warning before breaking traction. The problem with traction vs wear is that they are polar opposites. You can't have both. Anything is a compromise between the two extremes. Yokahama a032r's aren't bad but from what I can remember, but they don't even have a treadwear rating and may last you a few thousand miles. Neadless to say they won't be good in rain also. The problem with buying expensive street tires and using them on the track is that you can heat them quickly and chunk the treads. This is dependant on the weather and your type of driving. I guess my point is to get a set of track tires if you can. That way you can have the best of both worlds instead of a compromise inbetween.

old_skul · 04-28-2002, 08:45 PM

Quote:

Originally posted by 89911

The problem with buying expensive street tires and using them on the track is that you can heat them quickly and chunk the treads.

That's where I was coming from, 89. He's looking to stay with a single set of rims (like me), and get a set of extreme performance street tires that he can take to the track and not shred.

The Yokes have been good for me in that regard, and I've seen lots of people running Kuhmos and also Falkens with good results. I've also seen a guy toast a set of Hoosiers in one session - a $500 mistake - so I'm thinking a good set of street tires with a treadwear rating will do well.

JoeF · 04-29-2002, 03:04 AM

John,
What model Kuhmos do you suggest?
JoeF

AES · 04-29-2002, 03:14 AM

Most likely the biggest problem was cold tires. 45 ambient is pretty cool rain makes it worse. The first few des at LImeRock back in Aprill had more than the usual # of offroad excursions because of the low temps.
Don't get me wrong the Sumis aren't the best but they're not that bad either.

john_colasante · 04-29-2002, 04:54 AM

I was thinking the ECSTA Supra 712 was a good dual purpose street/track tire. When you're ready for a dedicated set of track tires you can move to the V700 Victoracer or the new ECSTA V700. By the way I can't seem to ever remember how to spell Kuhmo/Kumho.

Bags · 04-29-2002, 06:57 PM

Thanks for the input. Old_Skul, On my first wet session I lost it in 7 and in 8. OK on the second wet run and on the third wet run I lost it in 10. That was interesting with the retaining wall near by! Sunday, no problems or spins just alot more speed and working on smooth, smooth, smooth. I appreciate the tire delema. I am sure there is no perfect cross over.
Mike

old_skul · 04-29-2002, 09:22 PM

7 is fun, Bags! Especially if you can master that heel-toe downshift while braking really hard.

8, Dead Bear Turn, is just plain annoying. It's a long 180 degree off-camber sweeper, for the uninitiated, and there's no really good line through it, and serves only to point out that your car doesn't have any low end torque. And in the rain it's a sheet of ice - you can't go more than 35 through there while the track is wet.

Bags, be careful in 10! My car gets loose through there too - and the retaining wall is very, very close...

jluetjen · jluetjen's Garage

BTW - There is more to chosing a tire then just the hardness. The design, construction and tire pressures (all else being equal) also have a lot to do with the feedback that a tire will give. Did you ever try changing the tire pressures during the DE? You will be surprised at the difference that a couple of pounds can make. It rarely is a case of "more is better" but rather a a case of finding "just right". Regarding the other issues, a couple of simplifications which add to the complexitiy of the conversation.

* Tires with a rounded shoulder tend to be a little more forgiving then tires with a square shoulder. This is because they roll onto the shoulder rather then immediately lifting off the road when they reach the limit.

* Tires with a stiffer construction have a similar reaction as square shoulders. The trade-off is that stiffer construction gives more immediate results when changing directions. So tires that respond well to changes in direction may give less feedback before giving up. Also the thickness of the tread matters. Tires with deeper rubber on the tread generate more heat in the carcass. This is one reason (in addition to weight) that racing slicks often have thinner layers of rubber on the tread are are more suseptable to being cut by debris. Treaded tires by definition have deep rubber in the tread.

* Tire pressure: Higher pressure often makes tires act as if they have a stiffer construction. Higher pressure still can bulge the tread of the tire and make it act like it has rounded shoulders. Doing this does make the contact patch smaller though that lowers the over all level of grip, cause the center of the tire to run hot which increases wear, etc. etc.

* Tread Design: Street tires with smaller blocks and larger gaps between them (think rain tires) will squerm more near the limit which will increase your slip angles and tire squeel. It will also overheat the tread and cause the blocks to chunk off. Thin k rain tires in the rain. On the other hand, racing slicks have no blocks or grooves so they rarely squeel during on-track use. They also give higher levels of grip. >>> All other things being equal <<< they will also give less warning prior to break away since the entire contact patch will loose grip at once rather then on block at a time. BTW; shaving DOT approved race tires improves the situation by making the blocks shallower which makes them stiffer. Tire shavers can often also round the shoulder which modifies the tire further.

* Tread compound: Harder compounds will absorb more abuse then softer combounds. To a point, they will absorb more heat, but they also can slide more which increases heat and reduces grip.

I think that a lot of these issues are rolled up into the tire recommendations that you will get from this board. So if a lot of people say "Tire X", chances are that "Tire X" has reached a popular compromise. But keep in mind that every recommendation is based on that drivers technique, tracks and experience. So what will work for one driver at one track in a certain climate may or may not work for another.