Trans_Maro wrote: Everyone forgets that the doughnut is supposed to be installed on a NON DRIVE WHEEL The differential shouldn't even enter the discussion at that point. Shawn
What's a non drive wheel? 
Trans_Maro wrote: Everyone forgets that the doughnut is supposed to be installed on a NON DRIVE WHEEL The differential shouldn't even enter the discussion at that point. Shawn
What's a non drive wheel?
Trans_Maro wrote: Everyone forgets that the doughnut is supposed to be installed on a NON DRIVE WHEEL The differential shouldn't even enter the discussion at that point. If your blowout is on a drive tire, you're supposed to move a good, standard wheel to the drive wheel and put the doughnut in it's place. Unfortunately, the only person i've ever seen who has actually read the manual and understands this seems to be me.
I know as well. If you spend $800 building an axle with a clutch LSD, you never put a donut tire on unless you really like spending money on diffs.
Taiden wrote: What's a non drive wheel?
SlickDizzy wrote: WRONG. All speed tire ratings are for TEN MINUTES at their claimed rating. Not that that will change anyone's mind on here, but your claim is completely false, and I can't let that coast on by.
I'll check the link out later. My information was from a C&D article ten-twenty years ago, and C&D is one of the few magazines where I can take it on faith that they've done their homework.
My RX-7 experience was S-rated tires at 120-124mph for about 8 miles, every morning for about 8 months. I had a very fun, traffic-free, unpatrolled, and quick drive to work 
Too much traffic and brains to even think about trying that now.
As far as the topic title, 16vCorey taught me that dirtbike tires can be mounted to space saver skinny steelies with great success. We've never had a failure in that regard, but then again, from an engineering standpoint I'm sure high-speed rotational stress is VERY different than momentary axial stress.
I've thought about dirtbike tires as fronts for rallycross. Somehow I don't think that they are up for handling .7 or so G of side-loads in a 2500lb car, with the transient whumps that are hard enough to pull the inside tires off the ground...
Trans_Maro wrote: Everyone forgets that the doughnut is supposed to be installed on a NON DRIVE WHEEL Unfortunately, the only person i've ever seen who has actually read the manual and understands this seems to be me.
The only car I'm aware of that stipulated this in the owner's manual was the FD RX-7. The funny thing is, those cars had Torsen diffs, which in theory shouldn't care at all if the tires are a different diameter.
Knurled wrote:Trans_Maro wrote: Everyone forgets that the doughnut is supposed to be installed on a NON DRIVE WHEEL Unfortunately, the only person i've ever seen who has actually read the manual and understands this seems to be me.The only car I'm aware of that stipulated this in the owner's manual was the FD RX-7. The funny thing is, those cars had Torsen diffs, which in theory shouldn't care at all if the tires are a different diameter.
The SVX manual states that if you get a flat on the rear, you are supposed to move a good front tire to the rear and use the space saver on the front. Then put a fuse in the FWD slot to disable the AWD. They do not want you to use a space saver on the rear LSD axle.
When I worked at GM, one of my co-workers got a flat tire and was worried about driving on it for extended periods on the highway with the donut (she had a long commute at highways speeds of ~75 MPH). I remember the lead engineer at this facility, who had about 30 yrs of experience at various divisions of the company, said that the donut spares are tested for prolonged use (I got the impression it would be days or weeks worth of driving) at speeds above 85 mph.
Personally, I wouldn't have much of a problem running a set of these on a car with a trap speed around 100 mph, provided the tires were pretty new. I'd be much more concerned with how old the tire was. If it's been sitting in someone's trunk for the last 20 yrs, who knows how well it'll hold up...
speedbiu wrote: I was asking for drag racing only and sub 15 sec. runs.I can't believe this got so much attn.
Will there be any noticeable benefit to running skinny front tires on a car in that time bracket?
It would be pretty difficult to run most tires at their rated limit for even 10 minutes.
In reply to stuart in mn:
Yep it will decrease my front foot print by over a foot.
Question in a similar vein. I was gonna use a tow dolly to get my Rabbit GTi to the track with space saver spares on the rear while towing. Any reason I shouldn't/Can't? No hi-jack intended BTW.
speedbiu wrote: In reply to stuart in mn: Yep it will decrease my front foot print by over a foot.
I understand that the tires will be narrower, so the rolling resistance and aero will theoretically be improved, but will it be enough to really make a difference in your ET?
All my ET did was steal my vegetable steamer and phone home. Bastard.
Its worth a shot.Last year(2010 Challenge) Andy won by less that a sec.over the second place car.Both cars run in the 10s and Andy won by like .20 of a sec.I would hate to know I lost by that much without giving it a try.
Taiden wrote: What's a non drive wheel?
Something fast cars have.
dculberson wrote:Taiden wrote: What's a non drive wheel?Something fast cars have.
Oh like a reliant robin!
Exactly!
I am guessing that the evil government put the 55mph number on there to try and limit the number of people who put the wee little spacesaver on their car and think it works just the same as the other three. So they jump back in the car and start texting again, and graduate from having a flat tire to crashing in 5 minutes at the first on ramp, wet corner, jumping deer, drunk bicyclist, or whatever.
Emergency spares make cool rear wheels for home made bicycles. I am planning to use one on my next build....
You are asking a safety question that will be determined by the Gainesville track officials regardless of what anyone on this forum says. It's their track, and if they say no, the answer is no.
Be prepared for an alternative.
Since everybody else here seems to be in such a good mood, I'll be the naysayer. I wouldn't do it. At 55 mph, a tire's rotational speed is like 110 mph at the top of the tire (and 0 at the bottom). At 100 mph, it would be close to 200 mph of rotational speed. Donuts are simply not manufactured under stringent enough manufacturing techniques to insure balance at those kinds of speeds. If the tire construction is not uniform, a soft spot will be a potential failure at high speeds. It has very little to do with heat cycle or time sustained at speed. It is about simple physics and rotational force.
Performance of a stock 1984 Corvette would put it at about a 100 mph trap speed, so I'm gonna assume you are intending to go faster than 55 mph. Personally, I'd rather not hit the wall in a Corvette, even if it is a $2011 one. But you didn't ask my opinion.
I don't see any GRM folks weighing in on this, not sure how to interpret that.
The track officials will decide.
What about just the wheels, but using tires that are rated for high speed? I mean, wheels are wheels, right?
One Challenge team got turned away from the drags when they pulled up with the space saver tires on the front. They borrowed some 4x100s to complete the drags. Make sure you have plan "B".
I have seen the "no space saver" rule in MANY tracks gen regs. I have bever seen it in the big nhra book but they dont always cover things tgmthat seem obviously shady.
In reply to Paul_VR6:
The Mustang guys have did it sense the late 90's.They would run Lincoln town car space savers due to there size.Some tracks will not allow it(most are 1/4 mile tracks) but they are allowed at most 1/8 mile tracks or some cars that don't run over a given time bracket.The corvette guys run the 17in Pontiac GTO (94-97) aluminum 5 star wheels . Theres nothing shady about it.Its done all the time.I just wanted to hear first hand how they handled at high speeds shakes,vibrations,or wobbles??
SVreX wrote: The track officials will decide.
And that's the final word.
But I've seen bicycle tires on dragsters that run well over 200mph...
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