Thinking of changing the Turbo Rabbit TIRES

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Rabbit Farmer
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Thinking of changing the Turbo Rabbit TIRES

Post by Rabbit Farmer »

On the turbo Rabbit I have some really wide non-DOT tires (20 x 9.5 x 13). I'm thinking of running a skinner tire (225-45-13 / Hoosier A6) for a tire that last longer, therefore, would be more cost effective in the long run. The 225 tires would not work with the current rims (I assume they are 9.5" wide) so would have to look at other rims... think 7.5 or 7.0 would work?

So, from folks experience at the hills, would a set of 225-45-13 work on the Rabbit?

To give you a complete picture of what is currently on the car... they are 20 x 9.5 x 13" (the actual height of the tire seems to be 19.5"); the width of the tire is 11"; 1" of side way extends past the rim (9.5" rim + ~1" of side wall per side); contact patch is 10". I seem to be wearing a groove on the inside of the front tires. Also, I have some issues with over steering.... possible causes: old tires, tires are too wide, back shock/strut or spring, too much rear-sway, or OE. Alignment is good.

Steve
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sachilles
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Re: Thinking of changing the Turbo Rabbit TIRES

Post by sachilles »

https://www.hoosiertire.com/rrtire.htm
This should give you a pretty good indication of the specs/size and rim requirements.

I still think that tire wear was a combo of bad toe, and old rubber.
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Re: Thinking of changing the Turbo Rabbit TIRES

Post by sdwarf36 »

FWIR -when I was using my infared heat gun to check everyones' tire temp at the top of the hill a few years back, the tires on that car were BY FAR the hottest in the whole group. (like 245? I think) Dunno how that translates to anything--just info to think about.
Translating road racing to hillclimbing:
Proper tire selection== nothing hooks up on moss or wet leaves.
Staying on the racing line==anything paved is considered good.
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Re: Thinking of changing the Turbo Rabbit TIRES

Post by Rabbit Farmer »

The alignment was done at Ralph's before the season... perhaps I need to get it checked again before this season. It very well could be old rubber.

Sherman... yep, you mentioned to me that the tires were the hottest on the hill. Why? Don't know.. I do know that it is (more or less with that car, def. with every other car that I drove at Ascutney) foot to the floor above check 7 almost 100% until approaching corner 29 (not quite with the tub, as I know there is a zig that I left off to get it pointed the right direction)... perhaps I'm just spinning the hell out of the tires in the upper section of the hill. Don't know.... Perhaps old rubber = a lot of heat on the surface.
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Re: Thinking of changing the Turbo Rabbit TIRES

Post by Rabbit Farmer »

Hmmmm, per the link, a 20 x 9.5 x 13" has a recommend rim width of 7". The rims see to be wider than that.

I also found P225/45ZR13 has a rim recommendation of 7-8.5" (which is closer to what I think the rims actually are)

The Rabbit is supposed to be my hillclimb car and perhaps backup car, so long running good tires is a goal.

..... though, I think Ascutney will see the Golf over the Rabbit until I get some autocross time in the Rabbit....
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Re: Thinking of changing the Turbo Rabbit TIRES

Post by sachilles »

Are you certain that bushing and everything are 100%. My thought might be dynamic toe......the thing puts down so much power, it might be flexing somehow when the power is applied, changing the toe in power on situations.
Add some tire spinning and old tires, and voila a pair of corded tires.

One of the reasons for thinking that, is my research building the mini with VTEC. They get a lot of torque steer, and that is mostly due to the suspension not being rigid enough, causing flex in the arms and mounting points when power is put down. Given the amount of power that little rabbit has, I think it could do something similar.

I honestly think the tires being as old as they were have a big part to do with this.
I'm getting some 215/45 13's from a cmc'er at the storyland autocross. I'm ending up with 8. 4 are near the end of their life, and a season old. If you can help me get them back from storyland, you can have a pair for tire testing. They are A6's, I even have 4x100 I could loan for you to test them. They are narrower than what you are running, but I think they'd be worth testing.
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Re: Thinking of changing the Turbo Rabbit TIRES

Post by Mopar 151 »

Seth - I would disagree, having driven the car - on any sort of equal traction, the car has NO dart or torque steer - yes, I was surprised too!
Most of the flex in wabbits is in the frame horns, and the Rutan's fixed that in spades! As I understand the issue, any bushing compliance would be a problem.

As an old racers :ugeek: rule' o thumb, anything with production suspension parts and slicks or = needs to have alignment, :roll: ESPECIALLY TOE :shock: checked on a regular basis.

IMHO, on asphalt, with no wheel to wheel contact, you can go a LITTLE above the Hoosier reccomendation for rim width, possibly to advantage.
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Re: Thinking of changing the Turbo Rabbit TIRES

Post by britracer89 »

In conversations w/ the Rutan's and my own experience w/ FWD and slicks ...they wear. With the Charger we tried all different settings (some not drivable). All urethane bushings. My solution...get the car to go fast and still drive comfortably and stock up on tires.

We also tried different brands and sizes from 10x21-13 to 7X20-13, Avon, Goodyear and Hoosier. The best was 8x20-13 goodyear (soft) on 8 inch wide wheels. The wider tires seemed to make it harder to drive (twitchy).

But then I'm used to dealing with junk.
Just my 2 cents. Brian
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Re: Thinking of changing the Turbo Rabbit TIRES

Post by Rabbit Farmer »

I found a set of new tires that someone is selling... they are 2" taller (per specs), but for the price I might make them work. Racing should be affordable... :mrgreen:
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Re: Thinking of changing the Turbo Rabbit TIRES

Post by sciroccohp »

cantilever tires require a smaller rim then regular tires. my 20x8x13s are on 6 inch wide wheels. I believe they were specifically designed to get around rim width rules. the hoosier A6 is an autocross compound you may want to try a thinner road race compound. If you want to get rid of the 7 inch rims and run some 6 inch I would trade with some cash in your direction. We need 7 inch for the road race car. I run a 7.5 tire on the back because I don't think they get enough heat in them. And yes with slicks they do wear, they do get old and alignment is key. I am not going to personally worry about any of that until I learn how to drive and make sure it is the tires and car holding me back.
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