What is the best wheel/tire size in general for Autocross 16" or 17". As always - I am on a budget - so I am looking for a good autocross wheel/tire combo for a reasonable price - if the performance is identical I would opt for the 16" because the price is a bit less.

Thanks

Dan

07 Chilli Red MCS Sport Suspension & LSD

 

Not an expert on this but I have heard that 16 are best for autocross as the rims tend to be lighter. Also bigger rims is like gearing your car up a bit giving you a better top end but slows you down during acceleration.

 

rim size is irrelevant as far as "gearing" its the tire diameter that matters

 

You'll find most the national competitors run 16inch, and they use the light SSR comp wheels.

 

Which class do you want to run in, and which tires do you intend to run?

For Stock class (D Stock), your decision between 16" and 17" will likely come down to which r-compounds you intend to run. If it's Hoosier, you want the 225/50/16 A6. And if it's the longer-wearing Kumho, you probably want the 215/40/17 v710.

 

I intend to run D Stock. last year was my first year auto crossing (5 events) and the plan this year is to get new wheels and a good set of extreme summer performance tires - I do not think a set of R-Comps is in my best interest while I am learning how to drive faster... I just want another tire that is better than my current all-seasons. When those wear out - or - I learn to drive better - then I think Hoosier R-Comps will be appropriate. Your input was just what I was looking for! 16" it will be and less expensive to boot! Thanks!

 

dmyer: You probably already know this, but just in case ....

Your legal wheel options in SCCA DS are the OEM sizes (6.5X16" or 7X17"), with the same offsets as the respective OEM wheels + or - .25". The wheels may be aftermarket forged ultra-lights as long as they conform to that, but they can be expensive.

Thinking cheaper, some OEM MINI wheels are a little lighter than others. I haven't looked at 17s, but in the 16s, the R84 X-Lite (aka Monza or V-spoke) is listed at 17.6#, while the R83 5-star (aka Daytona) is listed at 20.1#, so the former would save 2.5# per corner. I've seen both of those wheels listed at a commercial site for $180 each.

I like your thinking on the tires for now. You're allowed to run any size tires that you can fit on the legal wheels, but don't get carried away; there's a point of diminishing utility to adding width. If I knew where that point is, I'd tell you.

 

Thanks for the tip about the x-lites! I got a set, supposedly almost new, for $300 of ebay. Off to the Tire Rack for some sticky summer rubber!

Dan

 

Good job on the wheels. Hope they're exactly as advertised.

You can ask Alex at TR about tire size, but I think you'll find more choices for sticky summer rubber in the 205/50/16 size than in the OE 195/55/16 size. The 205/50/16 has a diameter of about 24.1" (OE size is about 24.4"), and seems to be a popular alternative to the OE size. Even wider tires will fit on the wheels, but I'd be hesitant to recommend them for regular driving.

 

I was thinking about a set of the Hankook RS3 225/50/16 - $105 ea.... on thr TR website.

 

Oops, looks like I underestimated your seriousness. Those tires seem have similar dry grip to other extreme summer tires costing much more (including the RE-11s which I AX on a Porsche). Looks like a good buy. Hope they fit without rubbing, and work well for you.

 

Here is a compilation of tire tests by Grassroots Motorsports, Sports Car, and Car & Driver magazines along with links to Tire Rack tests.
https://www.northamericanmotoring.co...blication.html

 

Car and Driver did a nice review a couple of years ago, and the Hankook's won out for best performance for the money. And I had bought Azeni's just the week before...My luck...

 

My only concern is that the Hankook RS3 225/50/16 might be a bit wide for a 6.5" rim even if the specs say it is OK. Of course... with my driving it might not make any difference!

Dan

 

You should also consider the Dunlop direzza star spec tires. TheyRe decent for autox because they are quite grippy when cold.

Whichever tire you get should be oriented toward autox and have good cold handling characteristics. If you get Hoosiers, get the A6 and not the R6.

 

I'm pretty sure that I lost some steering precision in turns when I went to a slightly wider tire on the OE rims. I've read a lot of unsettled discussion about the point at which going wider on the same rims ceases to provide additional contact patch. The wider tires have to be pinched in a bit to be mounted, which tends to bow the tread surface slightly. Of course, the weight of the car helps keep them flat on the pavement. Regardless of the discussions, I've seen people run some impressively wide tires on OE rims in stock classes.

The .5" greater diameter will provide a very slightly higher effective gearing, and slightly more unsprung rotating mass; neither probably noticeable from the driver's seat.

Honest, I'm not trying to talk you out of those tires; I'm just trying to mention relevant considerations that an expert like Alex would probably take into account.

 

I think you should consul this with Good tire dealer and or Tire installer, because they knows which brand has the best quality and which fits the best as per the vehicle.
___________________________________
Yamaha Motorcycles | BMW Motorcycles

 

Not necessarily so, I think they are good for daily driver choices. But in terms tire set-up for auto-x they will not have the slightest clue. They would advise against anything other than stock sizing, let alone advise a shoehorned 225 tire on a 6.5 rim. Instead, they'll offer you only the all-seasons tires in oem size that they have in stock because they rarely stock Extreme Summer tires nor R-Comp tires. With the exception of tire rack or a trackside tire vendor. Also, the crop of ultimate auto-x tires changes nearly every year, most normal tire shops don't keep up with the tire wars.
The Kumho XS in 215/45-16 for $97 at Tire Rack seems like a neat tire size at a neat price.

 

 

Bigger rim (ie bigger diameter rim) = larger diameter tire for the most part (there are a few exceptions, but they really don't apply to a MINI). I run a 15 inch rim on the track, with 225/45/15 nitto-01's, and the end result is a VERY noticeable reduction in gearing, and improvement in acceleration.

Anyway, either tire is a good choice--don't get caught up too much in the tires at this point, seat time is the most important thing .

 

Getting some seat time tomorrow in Autocross school!!! Whoohoo

 

What wheels and tires will you be running in the "before" event tomorrow? We'll need a report following the first "after" event on your new wheels and tires. Another "Whoohoo" is expected.

 

I currently have 205/45/17 Michelin Pilot Sport Plus AS tires... not exactly an autocross/track tire... but they did just fine last year as an introduction... any of the Extreme Performance Summer tires will be a huge upgrade in traction... I plan to continue running the All Seasons for regular daily driving and switch to the other tires/rims for an event... they should last quite a while like that while I accumulate seat time and improve my driving....

 

Well I got to try the Hankook RS3 in an autocross today... What a difference from all seasons - OH MY GOD The 225/50 16 fit the mini great with no issues. I have not seen the final score but I was 24th out of about 80 last I saw and my times were a lot better and the time gap between me and the leaders was about 2.5 - 3 seconds less. I have no experience for comparison to for these tires - but if there is and max summer tire with more grip and feel than these RS3's I would have to see it to believe it! Thanks everyone that helped stear me right!!!

 

glad to hear it!

what are you using for warm pressures on those RS3s?