I've got a JCW MINI coming and am thinking about the Works wheels. I've been having more trouble deciding on tires and size than anything else about the car. I've currently got 17" all-season run-flats (hate the idea of being w/out on a car w/ no spare!) w/ the white alloys coming. I'm getting all-season because I live in the Pacific Northwest- wet is life up here. Could someone w/ some real experience tell me what the advantages to 18" wheels are? I'll get them in a heartbeat if I hear the right things- handling, stopping power, etc. If they're only about looks, I'm not interested. A rougher ride wouldn't surprise me at all, I'd expect it, and the ride on my 16" run-flats is already pretty rugged- can't imagine it could get much worse.

 

Advantage to 18" wheels- bling bling factor is off the hook yo.
Chris

 

>>Advantage to 18" wheels- bling bling factor is off the hook yo.
>>Chris

amen to that brother.

Also driving with 18" is actually less stiff than you'd expect as well. And from what I hear they will be lighter than the standard S-lites.

 

If you want to read a lot, read this paragraph, if not go to the next paragraph:
Let me start off by saying all of my knowledge has come from what I have heard and/or read so take it as you please. There has always been an on going debate about which wheel size is the best. If you look at auto-crossers, everyone is trying to get the small diameter legal and the main reason (well, almost the only reason) is because of the weight. If you want to know the key in performance as far as wheel/tire go, it is "the less weight, the better". Unsprung weight (anything that is not held up by the suspension, like the wheels, tires, control arms, etc) is said to be 4 times worse than sprung weight; that is to say that for every pound of unsprung weight (like from your wheels) is like loosing 4 pounds of total weight off your car (performance wise atleast). But the disavantage (an I know people differ on this ) to a smaller diameter wheel is that you have to increase the sidewall height of the tire (to match the orginal diameter of the orginal tire) this added height allows for more flex in cornering and thus creating a higher possibilty of tire's sidewall (where there is no tread) to contact the ground and thus you loss traction, as well as mess up your tire. NOW this does not happen often because you have to brake and corner hard and the tires have to be at or below the normal psi (for auto-xing and racing you pump of the tires to help prevent this). I read a article (I think from MotorTrend) where they tested the same car with 16 and then 17inch wheels on a course to see the difference and the 17 won by a small but obvious margin. The larger sidewall height and greater flex is said to be more forgiving because it doesn't go from grip to no grip (passing the limit of traction) as quickly or abrubtly as a less flexable, large wheel/tire combo.

So, from what I can gather, a 18 inch wheel that is lighter than a 16 inch wheel will significantly outperform (ic. braking, accel, and cornering) the 16 inch one. Now many will argue with that and the truth is that the JCW (even thought I have not seen any numbers) is almost for certain, heaver than the other already too heavy MINI wheels.

FINALLY, TO ANSWER YOU QUESTION:
The JCW (if they are indeed heavier than your current wheels) will NOT be a good option, performance wise, and honestly I don;t like the way they look either. Take all this type simply as my 2 cents.

peace

 

Small diameter to reduce weight is not the primary reason for small rims in autocross. Some sidewall flex is good, and performance tires tend to plant a wider traction patch with a bit more sidewall, as well as maintaining grip with the surface over imperfections due to sidewall flex and cushioning. Rubber band tires will tend to skip over bumps and ripples, and when airborne traction is pretty much nil...

So add that to lighter weight, and toss in cheaper overall packages, and you can see more why 15 and 16" rims are preferred for most national level autocrossers, or even 13" if they fit over the car brakes. Big brakes tend to be a driving force for taller rims more than anything else...

 

I'm pretty sure it's all about looks.


R.E.

 

Larger wheels use shorter side wall tires (in order to fit the same wheel well). A smaller side wall forces the tire to flex less, allowing "potentially" greater cornering forces. But in the same respect, the tire will begin to lose traction at the edge of the performance envelope more violently than a larger side wall tire due to flex. Unless you plan on racing, this means nothing. But, the shorter side wall also causes the tire to give a stiffer ride. Especially the case with reinforced sidewalls like in runflats. Large wheel, smaller side wall, stiffer, more harsh ride.

A heavier wheel will slow the response down in accel, decel, and cornering. More weight to change direction. On the opposite spectrum, a lighter will improve on these areas. However, lighter wheels reacting quickly may give the impression of instability... not the greatest fix for all owners in a car that naturally has telepathically quick reflexes. So a heavier wheel in effect gives more stability.

 

A lot of good discussions here! :smile:

The 18" JCW wheel supposedly weighs around 22-23 lb., which is lighter than the 17" R90 or the R85 that comes with sports package. 21 lb. isn't exactly the lightest wheel comparing to some of the aftermarket ones, but it sure does look nice, especially if you want to complete your JCW package. :smile:

 

JCW 18" wheels are all about looks and being JCW. They are heavy and costly. The tire sidewall isn't really that low profile compared to aftermarket options with 35 series tires.

18" rims are mostly looks oriented and the weights are typically quite heavy. You'd have to pay lots to get the weight down but it still would be heavier than a light 16" rim at a moderate price of $275 a piece.

If you want performance, faster acceleration and quicker shorter braking distances then go with light weight rims.
40 or 45 series tires will work well enough if you choose good sticky tires.

Often 18" rims are matched with 235/35-18 tires which may be noisy, rough riding, costly and may not last as long.

Advantages? Few MINIs sport 18" rims due to the drawbacks and cost. Therefore you will stand out more but there may be some sacrifices along the way.

 

A 17" wheel with 205/50s has a overall diameter of 25.1", a 16 with the same 205/50s diameter is 24.2, 15- 23.1 all with the same contact patch and sidewall height.
Now think of the extra rotating mass of the wheel and tire, it is going to take more hp to speed a 17" wheel to 100 mph because of the weight alone.
Say the 17, 16 and 15" combos all weigh the same. The 15" will get to 100 mph faster because the smaller diameter effectively changes the gear ratios.
17, 16 and 15" combos with the same weight, overall diameter, grip and contact patch, which combo would be the best? It should be a push, then go for looks.
A 17" can outpreform a 15", but the reason is a variable of either weight, contact patch, sidewall height, grip of the tire, overall diameter or combos thereof. I would like to see the article, since Motor Trend (or whoever) had variables that affected the results. One more thing, a heavier tire on a light wheel has more negative impact than a light tire on a heavy wheel even if the weigh the same because of the location of the extra mass.
Chris
I'm not a wheel and tire expert, I just play one on NAM.

 

I think because of these conversations more and more companies are just trying to mold the best of both worlds in looks, size and weight.
check out one thats coming out this year
when I see wheels like this, i dont have to worry about all these cases.
all I have to worry about is, if I can make it till the end of April to see them come out :smile:
17x7 4-100's ONLY GOING TO WEIGH 16LBS!!!!!!!!!

 

>>Chris
>>I'm not a wheel and tire expert, I just play one on NAM.

I came in with this guy......o/a diameter dictates acceleration (shorter=better) and top speed (taller=faster). O/A diameter being equal weight and sidewall flex are key. NO ONE thinks sidewall flex is a good thing. OK, ALMOST no one. So its weight if you race it at all.

Looks, Looks and Looks are all I need from an 18" wheel. Oh, and looks.....

did I say looks?? I meant to say looks.....

 

heres the damn benefit!


bling!

 

I didn't see this talked about, if it was I apologize. A heavier wheel and tire combo also equals a longer stopping distance. Now one other thing that I have heard about that is not proven, but a good theory. A heavier wheel equals more of a gyroscopic effect. So if you turn the wheel the gyroscopic effect will help to turn the car around a corner. This effect would only occur at higher speeds, thus autox would not put this theory into effect.

 

I had 18's for a long time on my cooper, bent two sets of wheels. They do look real good, but I think 17's look more appropriate. Plus as mentioned before, tires and wheels are cheaper in that size. I dont agree with these guys running 15 inch wheels, sure they are light, but they dont work with the high beltline of the car. Plus unless you are racing all the time (which nobody does) get something that pleases the eye not the go pedal. I have myself found 17's that only weigh 15.5 lbs each, but I have this obsession with wide tires, and put on 225/40/17 tires which are heavier than say a 205. All in all get what you like, and if you want to race on the weekends, get some wheels and tires just for that.

cheers, jason