As I wait for my MCS to be built, I have been enjoying all the topics on the G stock forum. Of most interest to me have been the discussions of available 16" x 6.5" wheels and their weights: SSR at 11#. NZO at 14.5# and stock MCS wheels at 17.6#.

Given the same tires on the same MCS, can someone possibly relate the performance of each of these wheels on a typical autocross course. Will the times be significantly better with the lighter wheels? Or is the difference only in the hundredths of a second and more realistically of importance at the national level?

Many thanks!

 

It's more important at the National level but it's more than a few hundredths of a second. I'd say more like 1-4/10's depending on course, or probably in the same area as the difference between running the best tire vs. the 2nd best.

 

SOLO2TIME,
Since you are looking at G-stock and all the wheels need to be roughly 16x6.5" and of similar offsets, then there is little difference in the rim itself except for "strength" and for mass or weight. Don't forget to factor in the weight of the tire into the total wheel weight equation. The heavier the tire the less the weight savings in the rim is a factor.

Strength- The SSR comps are the strongest. This plays a role when you are harder on your wheels and want to use them for track, autocross, driving events and the like for many years. They are quite durable yet very light. That's why they are expensive. NZO and stock wheels are similar in strength but at different weights to achieve that level of strength.

Weights- 11 pounds is alot lighter than 17.6 pounds. For four wheels that's 6.6 x 4= 26.4 pounds lost. The difference from 11 to 14.5 pounds is much smaller. The place where lighter wheels is going to make a difference is when accelerating and when braking.

Autocross courses- all vary with region to region. Speeds are limited by course design not to exceed highway speeds. If you have lots of tight turns and some long straights then it might be possible to make use of the lighter wheels to brake hard and accelerate hard out of turns when entering straights. If there are few long stretches then you'd want more cornering power without loss of much speed since you'll need more road to build up speed if you lost it.

Bottomline- you can loose speed faster than you can make it up. MINI stock brakes are plenty strong but power isn't equally strong. Once you get up to speed try not to loose too much with hard braking or you may run out of track to get your speed back up. Lighter wheels allow for quicker recovery if you slow down provided the track has long enough segments to speed up.

Reality check- In my experience watching various classes of MINIs at autocross for the past 18 months I have noticed that driver skill makes much more difference than wheel weight. A few pounds in the rims is not going to be a big enough factor until you can drive consitently at the top of your class in local and regional events. At the national level you look for any small advantage so lower wheel weight is a big plus and it might be worth one or two tenths of a second at best. Results will vary with the road conditions and with course design.

Fun factor- Personally I really like lighter wheels. I find them more responsive for street use, on the track or at driving events. But lightness usually comes at a higher price so you'll need to check your budget. I also find that if you take care of your wheels, the lighter wheels may have good resale value if you decide to sell them at some point.

Finally, The rim is not as important as the tire you choose, especially for autocross. I'd take a heavier stickier tire over a lighter tire. Any gain in weight can be made up for if the advantage in rubber compound is significant. The sticky tire might not last as long and it might also cost more per tire. Such is the price of performance.

 

minihune nailed it on the head

i'd look into sticky compounds.. maybe falken azensis or kumho escta mx... than getting a uber light wheel and spending less on tire.. its the tires that get the grip

of coze.. on a more wide open course light weight wheel makes a bit more difference than a short tight course where grip is more important

 

One thing that is good about the SSR's is that they are hubcentric, as opposed to the NZO's, which require a hub adapter. I've had both the SSR's and the NZO's. I always find it a pain in the butt dealing with hub rings.

I say, if money is no object, go for the SSR's. If money is an issue, stay with the stock wheels or buy some used NZO's if you can find them.

As far as differences, acceleration will be a bit better on course with the SSR's compared to stock. Also, more importantly, the responsiveness when transitioning will be better with the SSR's compared to the heavier stock wheels, this difference will probably save you more time that the acceleration since the better handling will allow you to carry speed more through certain high action area's of the course.

Bottom line is, if you have cash laying around, I say go for the SSR's

 

Thanks for all the good information. From what I read, it seems that if cost is a factor, then start with the stock rims. If then one's skills become honed to finish well in class, then it is worth the expense to purchase the SSR rims. And....as always....if money is of no object, then spring for the SSRs to begin with. :smile: