Are tire warmers allowed

[slngsht]

under solo rules?

[Mandurath]

Why would they not be?

[slngsht]

not sure if there was anything in the rules against them.

 

since my tires are [caugh]oversized[/caugh] it'd make a huge difference for me.

[yellowss7]

No Mazda, powered tire warmers are NOT permitted under SCCA Solo regs. However, a number of guys have made homemade warmers out of heat duct insulation material. I've made a set myself, but don't know how much heat they actually hold in. Tom

[slngsht]

No Mazda, powered tire warmers are NOT permitted under SCCA Solo regs. However, a number of guys have made homemade warmers out of heat duct insulation material. I've made a set myself, but don't know how much heat they actually hold in. Tom

 

yeah, that's what I meant. Bummer.

[Boxologist]

:willy: going sideways thru the timing equipment builds heat quite quickly:lol:

[slngsht]

:willy: going sideways thru the timing equipment builds heat quite quickly:lol:

 

heh, you saw my problem first hand... my tires are as cold after the run, as they are before.

 

 

[Al N.]

Can you do burnouts a la drag racing? Won't do much for your fronts, but the rears will be sticky.

[slngsht]

well, you could at the start of your first run, I suppose. Can't do it in the staging area. Plus, warming up the rear without the front, will make the car push more.

[yellowss7]

Move on up to nice soft slicks. Makes a difference. And Al, stop ducking this Sunday's autox, I know you've read the post. Tom

[Davemk1]

Narrower or softer tires will help a good bit. You can use blankets to keep the warmth in but if you can't generate any heat there is nothing to keep in. Narrow tires will heat a good bit faster and get warmer and will therefore generate more grip. This is of course for autocross only. Road racing is a different deal...............but for a 1 minute autocross a warm narrow tire will kick the snot out of a cold wide one.

 

A few seasons ago I asked the tire tech guy at Hoosier what tires he'd recommend for my Birkin.........roughly 1450 pounds with the driver and 140hp. I was expecting to hear him say 10" all around or something like that but that wasn't the case. He recommended 7" in front and 8" in the rear. If I were to up the horsepower he'd suggest going up an inch in the rear and maybe in the front. I asked him why so many folks are running such wide tires on such a light car for such a short event. He says Hoosier recommends against that but that fashion and trends dictate stuffing the biggest possible tire you can under the car regardless of how well it works. In some cases, it does indeed seem that less can be more.

 

I've cut and pasted an email he sent to the D-mod email list a while back. I took his advice and it works in a big way. He letter is just below -

 

 

Subject: Hoosier Tires for Autocrossing a Seven

 

 

Good talking with you this afternoon about tire fitment for your Caterham 7.

Here are a few thoughts we talked about pre-Solo event and post-Solo event.

First, the DOT A6 competition tire is designed for heavier type vehicles

ranging from 1700 - 3000 pounds. Vehicles under this weight should benefit

more from using our bias ply slicks which you currently use our item

43182R25A - 20.0 x 9.0 -13.

 

Now, the new Topeka surface was quite confusing, where throughout the year

at other autocross events, the bias ply slicks should have an advantage with

more initial grip than the A6 which needs some force/weight to generate

heat. The Topeka surface proved differently with many people running faster

times on the DOT A6 tire. The specific surface(lots of sand) and cooler

temps allowed this to happen. I believe it will take several years of Solo

Nats to rough up or break in the surface to allow the bias ply slicks to

grip better than the DOT A6's.

 

On to your setup, if you find the 20x9-13 on a 10.0" wide rim is not

providing sufficient grip, you should look at running a narrower rim and

tire, using a 7.0 - 8.0" wide rim and using our item 43161R25A - 20.0 x 7.5

- 13 R25A on the front only with your 20 x 9 - 13 on the rear or the 20 x

7.5- 13 on all four corners. The narrower tire should develop heat quicker,

but tire wear will increase somewhat, depending on driving style and surface

type. This narrower tire combination could offer a second option to

slick/sandy surfaces and cooler air temperatures while the wider tire option

could be used for hot summer days. Having two tire size options may not be

feasible for some because of transportation(carrying 8 rims and tires) or

cost.

 

The other option would be to run the item 46307A6 - P225/45ZR-13 A6 on the

less than 1700 pound vehicle using the 9.0" - 10.0" wide rim which seemed to

work for a few Solo prepared and modified competitors at Topeka.

 

Finally, all of this information is a theory or my best suggestion working

with tires for 15 years here at Hoosier Tire. I always stress that changes

to your wheel/tire combination needs to be track tested before heading to

the Solo Nats.  Feel free to pass some of these thoughts on to your Caterham

7 group.

 

Jeff Speer, HRT

 

 

 

 

 

You might also consider spring and damping rates. It sure seems like the trend is to go very stiff.........but remember if you are sliding and there is very little body roll you might be too stiff. The original Seven, like most Lotus, was design by Chapman to have very low spring rates and high damping to control movement. These are for the most part very light cars and they like light spring rates for autocross. In road racing where transitio

[slngsht]

Move on up to nice soft slicks. Makes a difference. And Al, stop ducking this Sunday's autox, I know you've read the post. Tom

 

I'm bidding on a set of used Kodiak wheels for a vette on ebay right now... I can't afford new ones at the moment ($3k). if that doesn't work, i will find a set of used vette wheels for mounting slicks. But the heat problem will be the same.

 

I'm not after the ultimate autox machine anyway, so I guess it's all relative. Dave, your point definitely makes sense about going narrower. My car is about 400 lbs heavier than yours, and I'm running similar springs all around (200 or 225 in the rear, and 425 in front right now - although I'm not sure if our lever ratios are the same).

 

If I lived closer to Al, I'd drive over there and escort him to the autox

[slngsht]

somehow I need a built-in heated air system for the tires :leaving:

[Al N.]

If I lived closer to Al, I'd drive over there and escort him to the autox

 

Alas, my participation is iffy...there is also a group drive headed up by Atwell and company, basically in my back yard.

 

To pre-empt Box's (and Tom's!) inevitable ragging on me to go...in recent years, I gave up cursing and drinking for Lent. My willpower (when it comes to things besides spending money on the car) is strong.

[yellowss7]

Al, no need to preregister, I doubt we will sell out. But if the weather holds, and we run 1st this time, you'll be done by 1:30 at the latest. I've already lined up an instructor for you. Nice light guy, National champ in Pro Solo.

 

As for Dave, did I read that right? Your front spring rate is 350 pounds!!! I think my stock Caterham springs are 175's. I ordererd a set of the race springs and they are only 250's.

 

That's a huge discrepency. Tom

[slngsht]

Tom, it's possible the actual lever ratio of the springs are different. In mine, when I had inboard, the ratio was 1" suspension travel = 1.1" spring travel, so I was running 225 lb/ in. now it's about 1"=.56", so much stiffer springs...

[Davemk1]

Al, no need to preregister, I doubt we will sell out. But if the weather holds, and we run 1st this time, you'll be done by 1:30 at the latest. I've already lined up an instructor for you. Nice light guy, National champ in Pro Solo.

 

As for Dave, did I read that right? Your front spring rate is 350 pounds!!! I think my stock Caterham springs are 175's. I ordererd a set of the race springs and they are only 250's.

 

That's a huge discrepency. Tom

 

That's interesting about your springs. I wonder what the effective rate is with the angle? What are you running in the rear. I assume the rears runn more or less straight up and down.

 

Dave

 

 

[Boxologist]

 

Alas, my participation is iffy...there is also a group drive headed up by Atwell and company, basically in my back yard.

 

To pre-empt Box's (and Tom's!) inevitable ragging on me to go...in recent years, I gave up cursing and drinking for Lent. My willpower (when it comes to things besides spending money on the car) is strong.

 

I was gonna lay off this time and hassle u next year after u still had not improved the nut behind the wheel. Tom and I had PM'd each other about getting u a personal instructor for the day to see if that can give u better grasp of the day on course. Tom beleived my choice would not even fit in Orange, so i'll have to have him co-drive Snake Bit next year. Tom's too overprotective of his 7. i think last event was the first time he let someone else drive on course IIRC. I on the otherhand will basically throw the keys at anyone i beleive competent. My car gets whored out way too much

 

back on topic, Caterham coilovers are about a 50* angle with the ground. i'm on stockers and they are valve and sprung nicely for my local crappy roads.

 

I persoanlly expect to be on 205 front, 225 rear width for 130-145 hp. above that power i'd consider going wider a bit.

 

as for a tyre warmer, just buy a bat of 16" or wider fiberglass batt insulation and use that for the time being.

[yellowss7]

Dave, my rear springs are progressive, and I recall 150 pounds as the max number. Again, stock for the Superlight.

 

Jon, did you notice the poor fiberglass job on the right rear wing? I've had the car driven by several of the top drivers. and they thrashed it pretty good. See rear wing picture. Well, actually that was me driving in that picture. But that wasn't the first time, and probably won't be the last. It's just the yahoos, who want to drive it that I don't let near it.

 

http://www.usa7s.com/aspnetforum/upload/386541946_Warminster 07 4jpg.jpg

 

I'd gladly let you or Al drive it if you think you can handle it. tom

[Boxologist]

...I'd gladly let you or Al drive it if you think you can handle it. tom

 

And Mazda calls me INSANE:lol: