Why not? In street prepared, fender modifications are allowed, and the diameter is shorter than the 225/50R16's, which have been used, and weigh only 1 pound more (well, the wheels are probably around 16-17 pounds?). Is this dumb? Am I missing something?

 

285?

 

DO IT! I want to see that.

 

Be orginal. Thumbs up.

 

That would be pretty freaking sick man... your tires may be so large that they touch each other .. but big ups for originality thats for sure

 

Well, I'll be in GS next year, so none of this for me. I was just pondering the possibilities and the street prepared section here has been kind of dead lately.

Jake

 

now thats an interesting idea!!!

for ingenutiy (sp)

 

THIS HAS GOT TO BE THE SLOWEST FORUM ON THIS SITE!


IS BEEN 12 DAYS... AND NO ONE HAS POSTED ANYTHING ABOUT ANYTHING... NO NEW THREADS NOW REPLYS! geez

 

Excellent post.

Short, but pointless.

 

Nice location...

 

Jake

Now that the JCW has been put in STX, I'm now thinking about doing the STX/DSP thing and then hoping into GS for the west coast stuff and maybe Nationals depending on how STX/DSP shakes out. I'd need to get a couple sets of arches though, one for SP and one for STX since the SP ones would need some modification, but, I would think there should be a way to get some serious beef under the Mini in SP trim. Not sure if it would be beneficial over some 225/50/16 or 15's though. I guess it might be worth checking out though. It really all depends on if I can get a couple manufactures/distributors to kick in some sponsorship for the cause though. :-))

Craig Wilcox

 

you must mean excrement post...

 

Don't even attempt to put 285s on your car. Trust me. Your steering feel will be horrible, the car will be anything but agile, and your mileage will go to hell. Especially considering you're talking autocross....you'll honestly lose time if you do it. Waste of money and effort. Just ask Onasled...he's running 235s and he's volunteered that he would NOT do that again if you he could re-do it.

 

With kudos to ingsoc for bringing this back out of the gutter, I have to agree that anything over 215 or 225 is going to negatively affect your steering, and anything over 215 is going take your fuel economy straight down. Heck, I've noticed a loss of over 2mpg just for going to 215 (from 195 stock).

285 would only be rockin' if you were drag-racing.

 

What he said ^^^^^!

 

This thread is about building a Street Prepared class race car. What does fuel economy have to do with a race car, particularly one that only has to run for 60 seconds at a time.

285's under a MINI would massively improve lateral grip, more than making up for a little numbness on turn-in.

 

I'm sorry, but 99% of people with MINIs see more road than track. That is fact, even amongst avid racers here. Heck, at least 75% of SP competitors at my usual autocross dig drive their cars to the track. That said, what makes you expect "a little numbness?" It is a LOT harder to turn a ~2500 lb car on 285 series tires. On a real race car, this is just not an option. There are much more elegant things to do to increase lateral load capabilities of a MINI than ruin its handling with 285 series tires.

 

Street Prepared and wheel/tire size is something I don't totally "get".

Why do most of the small bore cars run 13x9's or 13x10's? Maybe I'm just a lemming, but I'd think that'd be the way I'd try to go if I was crazy enough to build an SP Mini.... Although I don't think you could find 13's that would fit over the Mini's brakes.

Why don't any of the fast SP Miatas or VW's run a bigger wheel and the associated wider tire? Is it just a gearing issue? Is a tire wider than 225 past the point of diminishing returns for such fly weight cars?

I do recall an interview with Bob Tunnel about his M3 back when it was in SP, and he said that 245's were about right for the car ... anything wider was too hard to get up to temp in 1 autocross run, and anything narrower got too hot. That'd depend on compound and stuff, of course, but this was back in the era when you used Hoosiers, or you lost.

 

I have to wonder about this comment. If I was an SP driver that drove my car to the track, it sure wouldn't be on my R-compound tires no matter what size they were, leaving me with the flexility to drive to the event on the most fuel efficient wheel/tire size available. You must not be in a very competitive region - I would say that 97% of the people that are in a r-compound class in our region either trailer their car in or drive their cars to the track on different tires than they compete on.

satay-ayam makes a good point about tire heat, but I wonder if that would be less of an issue with the newer compounds that heat up so quick. Probably even less with a dual driver situation.

I do think this would turn the car into more of a momentum car like the miatas, but they have success with it (so do the HS mini's). So it would be less forgiving than the powerful BMW's in DSP, but it would have WAY more grip considering the Mini's are so much lighter. I think one could get used to a numb steering feel if the benefits were there.

 

But, how funny do you reckon it would look for someone with fendors bent out at least 60mm [~2.4"] to drive around a car with 80 mm narrow tires on the street? . Yes, most SP drivers who drive their car to the event come on different wheels and tires, but not all, not by a long shot. I personally know more than a few people who use R Compounds on the street. It's an expensive treat, but that's what they do. R Compounds ARE street legal, DOT approved, you know...

So, yes, IF one plans on modding their fendors that much, I would seriously doubt that they would be willing to run much "narrower" tires on a daily basis. They would most certainly choose nearly the same width on the street.

By all means, those so wishing can go and mod some fendors and try it out, but they should not expect much nimbleness and steering feel at all...

A couple more things: in order to fit 285 series tires on a MINI, you'd probably have to run some ridiculous offset, like -40, to even turn the wheel [considering that most aftermarket wheels usually employed are like +40 offset at least and most people run 205 or 215 series at widest]. You need to pick up the 80 mm somewhere... Lastly, why on earth would someone looking to build a proper SP autocross car run heavy 18 inch wheels? That, too, will hurt track times, simply by the mechanical disadvantage of the large weight toll.

 

A couple more things: in order to fit 285 series tires on a MINI, you'd probably have to run some ridiculous offset, like -40, to even turn the wheel [considering that most aftermarket wheels usually employed are like +40 offset at least and most people run 205 or 215 series at widest]. You need to pick up the 80 mm somewhere... Lastly, why on earth would someone looking to build a proper SP autocross car run heavy 18 inch wheels? That, too, will hurt track times, simply by the mechanical disadvantage of the large weight toll. [/quote]

WELL..

you would probably have to have a set of custom wheels made.. fortunately i can think of about 4-5 manufactures who would love to take this kind of project on...

also... remember not all 18 inch wheels are created equally! 18 inch wheels can be made to be incrediably light... it just depends on how they are made... if you spend big money i.e. a set of wheels made... you will probably have some pretty nice light weight wheels...

and remember often times people use larger diameter wheels so that they can gain width in the tire (its just because thats whats available from tire manufactures) which happens to be the whole point of this thread.

 

The other reason to go with the 18's is the tires are significantly shorter than the 16 and 17 inch tires available. So less effect on the gearing.

If you want to compete at the top level of SP, you end up with a car that is not very streetable. If you are not thinking about how to squeeze giant tires under the car, you are not trying to be nationally competitive. It's all about your goals.

 

Again, how can you say that? Are you nationally competitive in SP? Do you know someone who is? Have you known anyone who drove a MINI with >225 series front tires, much less 285 series? As I said above, onasled runs 235s and has commented more than once about how he dislikes them. I've pmed him about it. I have a hard time believing that you could ascribe national competitiveness [or the absence thereof] to choosing such a ridiculous tire size.

A note about 18" wheels... No matter how heavy they are, by virtue of the fact that much of their weight sits further from the hub, radius-wise, they require significantly greater power to spin them- it's all physics. The longer the arm supporting a given weight, the harder to raise it. Truly nationally competitive MINIs run 15s or 16s, maybe 17s for style, from my reading. You're welcome to find a "nationally competitive" car running 18's, if you can, but then explain to me exactly how those cars which aren't running on 18's became so competitive, according to your reasoning...

 

Consider also that you'd increase the load on the wheel-bearings by quite a lot. I had to stop running on my SSR Comps because the offset was such that it made the bearings heat up too much. No matter how you offset those enormous 18x10 or 18x11 wheels, you'd be moving the load much farther out than stock.

And you still would not be able to steer the car effectively. Seriously, is a great launch going to make up the extra 5 seconds you spend trying to get those huge lunking shoes around the cones? Or, for that matter, how long will it take you to learn the new dimensions of your 4-inch wider car, so that you won't hit the cones? You could just forget the slaloms and wipe out the cones, hoping the penalties will be made up by your increased speed.

 

Nobody is currently running a nationally competitive MINI in DSP or FSP. As for cars running 18's... all the trophy winning BMW's in DSP at nationals were running 18's. I know for certain that the top 5 were running 285's.

No one runs the 225/50/16 on a MINI because it is 2 inches taller that the 215/40/16 and only 1/2 inch wider.

If I were to move my car to FSP, I would be looking for a 14 inch wheel to fit over the brakes, to be able to run the 225/50/14, since it is an inch shorter than the 225/50/15. I would also be looking at the 245 and 285 18's to try and get the extra width.

None of this has anything to do with what I would run on the street.