I just moved into this club and love it . Please, post your wheel a tire combo with the total weight!!

15" OZ Superleggera 10.9 lbs
195/60/15 Kumho ASX 19.1 lbs

for a total of only 30 lbs !!

 

I gotcha beat by 1.5 lbs overall (wheel+tire)

Stock 15" Holey wheel = 12 lbs
Toyo T1R 195/55-15 = 16.5 lbs

I'd love to get some 8.8 lb 15x6 SSR wheels, but I can't justify the expense for just street use, and they wouldn't work for stock class autocrossing. The SSR wheels and my Toyo tires would come in at 25.3 lbs each though. Maybe someday......

-Keith

 

Good. You can answer this. What is difference in acceleration control feel? Does the car now have more of a tendency to want to spin the tires during hard acceleration in low gears? With all that extra sidewall, have you noticed thecar being less capable in cornering? I'm glad you're happy, but what are the cons? Thanks! By the way, at what weigth do most people consider the wheel is light weight? TireRack calssifies wheels in the low 20 pounds as light weight. Me, I think anything under 20 is a step in the right direction. I also think there is something as too light. And that's the threshold I'm searching for. If too light is causing adverse behaviors such as a tendency for the tires to break free under acceleration, then that is no good (not to mention to havoc it would cause on tire wear).

 

10.6 pounds and forged for urban assault as required to get in and out of Boston with minimal fear of pothole bends...

but put on 205/55-15 pole positions which do weigh a bit,,,, I think like 22 pounds...

but still lost almost 50 lbs unsprung weight when I took off the x84

 

Too light is when a wheel folds up after hitting a pothole. Traction issues just mean that you need to find a better tire, have an LSD installed, or learn throttle control.

Light weight wheels do not change the footprint of the tire or the tire/road interface. Light weight, especially unsprung weight, is always good and improves preformance.

 

I didn't want to get into theory, but did want a practical assessment from someone who knows by experience. I have LSD on my '05 MCS (that's not on order), and I'm familiar with unsprung weight benefits. I removed my 4 lb. flywheel and 4 lb. clutch basket from my Ducati and replaced it with a 8 oz. flywheel and 2 lb. basket. While this isn't unsprung weight, the affect with lighter wheels and lighter final drive gear (50% lighter than stock--all unsprung weight) caused the bike to be near dangerous during hard acceleration due to the excessive wheel spin (bike is capable of 0-60 in the 2 second range). In fact, having to "learn throttle control" kept the bike from "gripping and going", which ended up working against "performance" as you say. Aside from wheel strength issues or having to buy stickier tires (not intended variables), there's got to be a new set of characteristics (that all can't be positive) that super-light wheels exhibit. That's what I'm after. I'm interested to know if there's a change in launch control and torque steer due to the substantially lighter wheels. There should be a change in cornering just due to more sidewall flex, assuming tires of similar character are mounted. I have R99s for summer and R84s for winter, and the driving characteristics are night and day. I'm sure this is mainly due to the rubber (Dunlop SP Sport 9000s VR runflats vs. Goodyear Ultra Grip HR winter runflats), but some could be to the lighter wheels. So, back to the original questions I hope...

 

I think motorcycles have different characteristics than cars, and you changed the engine rotating parts on your motorcycle, which is different than the unsprung weight issue. I don't know all the answers, I'm just guessing about all this.

I think there are no wheels made yet that would be too light. 8, 9, or 10 lbs would not be too light, because tires are still quite heavy, so the combo is still reasonably heavy, i.e., 25 lbs or more. If the total weight was maybe 10 lbs, there might be an issue with the shocks being calibrated for something heavier, but that may be the only issue I can see. I'd go for as light as possible, and you should be able to feel the difference. Others have posted improved results and many believe that adding lightweight tires and wheels is one of the first and easiest ways to improve performance, both speed, handling, and braking. Have fun!

 

17"x7" BBS RGR = 16.1lbs
205/45/17 Michelin Exalto PE2 20lbs

36.1lbs

Acceleration, braking and steering response all benefit from lighter wheels - so long as strength is retained, the lighter the better. Controlling wheel spin will always be a challenge for light weight high hp cars. Although the mini is not a high hp car, 210hp my case running thru the front wheels with the stock suspension allows for quite a bit of squat. This removes weight off the front end. If you remove acceleration from a stand still from the equation, lighter is always better, period; it takes less engery to keep lighter wheels rolling, takes less effort to stop them. In addition, the perpendicular gyroscopic effect of a spinning wheel tends to keep a wheel pointed straight ahead. If the wheel is lighter, steering repsonse improves because this effect is reduced.

Reducing unsprung weight is always beneficial and wheels are the easiest place for weekend warriors to begin.

 

SSR Comps 16x7.5 = 11.5lbs
GY F1 GS-D3 = 22 lbs (?) 205/50/16

so about 33lbs for street use.

 

Kosei Racing 17" 12lbs (if I remember correctly)

Wheels change with mood when I burn up the last pair, but I find most are about the same weight wise.

 

15" R81 holies - 12.1 pounds
Stock Continental all-seasons - 16 pounds

for a total of only 28 lbs!

 

If Kosei Racing K1s in 17" weigh 12lbs I'm in heaven. Unfortunately on earth they weigh 16.1lbs. The Kosei T1s weigh 14+lbs in 17" but have a split-spoke pattern and don't appeal to me aesthetically. The K1s are also about the easiest wheel to clean! The K1s are no longer made.

cheers

 

I heard the K1's had some quality control issues involving the wheels being out of round. The K1-TS's didn't have this problem though.

I agree that the K1's look sweet but the K1-TS are lighter and stronger. If I had money, I'd get some SSR Comp or Advan wheels. Until then , I'll stick with my plan on getting some K1-TS's.

 

I notice a difference when I switch between my summer R84s with Dunlop 5000a runflats at 40.6lbs each and my R81 with Contis at 28lbs. I'll let you know what has changed this year as I have switched to Nokian Hakkas and they are a little heavier (29.2lbs each). I can feel a difference in the ride when I switch wheels, probably due to the increased sidewall height. Turn in and basic changing of direction seem just as sharp with the lighter wheels in spite of the taller sidewall, this I believe is due to the lighter weight.

I do feel that the wheels spin easier, but I think that most of that is because they are so much narrower tham the summer tires and a different compound.

I know that the top Auto-X people go out of their way to find the lightest wheels and stickiest tires when they are having fun on the course. I have never heard any one of them recommend against any wheel or tire simply because it was too light.

I think that is where you should be looking for the answer to your question.

 

Take all this for what its worth, as I'm not a pro, I've won a few local championships, but I'm no where near national level. Anyhoo, top AXers and I know quite a few national champions, are after a few hundredths of a second where ever they can get it. I know someone who paid $800 to import headlights from Japan as they were 2.5 pounds lighter than the US versions and were considered legal in SCCA for a stock class. A few hundredths often blanket the top half a dozen finishers at Nationals. Sure lightness is a good thing, but for the $$$, is it worth it for a street application? I'll probably AX my incoming Mini next year, but as I operate under no delusions about my chances in Kansas, I'll find a set of Koseis and pass on the SSRs.

I'd be willing to bet that the differences you are noticing are down to the tires, conditions, air pressure differences, etc and have little, if anything, to do with the amount of unsprung weight. A fair test would be the same tire on two different rims say 12# versus 20 at an AX on the same day. On my track car (911), this season I ran hoosiers on some fairly heavy BBS rims and Toyo RA1s on my much lighter Fuchs. Probably a 10# difference at each corner. All I noticed was the grip differential. My data logger shows pretty clearly that the car was faster with the Hoosiers both at AX and ontrack despite the added unsprung weight. I can think of only one corner on track where the extra weight might have had a noticable impact. To be fair, I totally rebuilt the car last winter and this year was spent relearning the car and finding a decent setup. Maybe when we get it fully dialed in, it might be detectable, but this is in a car with a $10K race suspension that weight a couple of ticks over 2000# with 250rwhp. In a side by side in this car at an AX the toyos delivered ~1.2G max, the hoosiers ~1.3G (same day, same course, it a narrow body so not much rubber). Tires are undoubtedly the biggest bang for your $$$. If you're in a formula car with triple adjustable Ohlins maybe you need to obsess about this stuff if you want to win at the run-offs. In a one and half ton (including driver) street car, as far as wheels go, I'd be more worried about strength than weight. Its the tire you choose that will make the ultimate determination about how much performance you can muster.

 

Kosei wheel are indeed light for a cast wheel. They do suffer from flex during hard cornering - personal experience. too light for a cast wheel in my opinion.

 

meb- wat are your thoughts on Rota wheels? those are cast too,
aren't they? Those subzero's are pretty light weight.

 

I only have experience with these Koseis in autoXing with a four bolt pattern. They are quite unbelievable for the price though. I'm comparing them to a forged wheel. so what I wrote may not be fair..this conversation mode irritates me; so much dialogue is muted.

Plently of folks use Kosei wheels successfully. What I wrote was unfair. 10 days of hell at work and it shows up in everything I say and write...is there a couch around here anywhere?