cashout

Just looking around for wheels for the smart (not very seriously) and I finally found the weight specs for the standard and optional wheels.

To my surprise the $5000 Monoblock VI wheels are almost 3kg heavier than the standard wheels. I know, they are 17" instead of 15" but these wheels are advertised as improving performance and they cost $5k for goodness sake!!

I wouldn't expect Vueys sub $1k chromies to be any lighter than the stock S2k wheels but for $5k it is a different story.

So, how much performance improvement am I gonna get for $5K?
Is is all in the wider tyres (205 front and 225 rear Vs 185 front and 185 rear)?
Is the rubber lighter (because there is less shoulder) and that makes up for the 3KG?

RedRover

The true question should be "So, how much performance decrease am I gonna get for $5K?

You should read up on the difference between sprung weight and unsprung weight. As well as more grip the wider tyres will also provide increased rolling resistance. This is a trade-off between better cornering versus straight line speed and acceleration.

cashout

OK ( I did and understand)

I guess I always thought the more you spent on the wheels the lighter they would be (as a rule of thumb not a strict formula!) when compared to stock wheels.

The next question is then: What sort of time savings would you see at a track (say ECreek) by going to a wider tyre (say 185 to 205) if weight was not considered? Bear in mind that my fastest lap at ECreek is 2:13.xxx so far.

Vuey

ahahahhaa

i got them for $2800 including tyres .


As for heavier wheels and performance ? MRWRX did a 10sec pass on his 20in Gold/Chrome wheels !!! hectik uleh !


why dont you get some 20's for the smart ? would look hectik !!!
a few of the guys crap on about how important it is to have light weight wheels etc, do how often do you drive your car at 10-10ths a day ? if you did you wouldnt have a licence !
Save the $5k and work the Turbo on the smart !!!

RedRover

A wider tyre will give you better cornering grip, but because of the increased rolling resistance you will have less top speed. A narrower tyre will give you a higher speed but reduced cornering ability.

The choice of width is always a compromise between these two factors. For a fast track with lots of straights the narrower tyre might give best lap times whereas on a tight & twisty track the wider tyre should be best.

It is probable that the Smart engineers calculated what the optimum width would be for most conditions when they designed the car. For such a small light car, 185 is already a "wide" tyre.

Eastern Creek is not as tight & twisty as say Wakefield or Winton but nor is it as fast & flowing as Mt Panorama or Phillip Island. Sort of in the middle between all those. Consequently, for Eastern Creek I would suggest the following options:-

1) Spend $5000 on larger heavier wheels (plus $??) on new tyres and thus increase your lap times.

2) Spend $2000 on the best competition tyres you can buy for your existing 185 wheels and reduce your lap times.

3) Spend < $1000 on a new set of chromies. Who cares about lap times when you've got "the look"?

cashout

If I remember correctly the Elise comes with 185 tires standard so you are probably right about that. Only comment would be that the wheels i am talking about are sold as factory options so I would have thought the same sort of engineering exercise would have been put into them.


I will seriously think about that when the current tyres need replacing. The stock tyres are Bridgestone RE340 so i am sure I can find sticker ones easily (although maybe not on 15" size). I have about 1/2 thread left though (40k kms + 5 track days). The only part that shows wear is the outside of the front tyres due to the built in understeer and the track days.

RedRover

$5000 wheels are a marketing exercise.

AusS2000

There is no direct weight/price correlation.

You can spend $100K and get a real heavy set of diamond encrusted 20" dubs.

Or you can spend Spend $5K and get a set of forged P1s that weigh about as much as a package of chips.

But the fact is, if you want a really lightweight strong wheel it will cost heaps simply because the manufacturing and quality assurance is so costly.

DavidM

If I remember correctly the Elise comes with 185 tires standard so you are probably right about that.

185s at the front, but 225s at the back. Generaly speaking, the extra width is needed at the back to be able to put the power down (ie. for traction out of corners).

What sort of time savings would you see at a track (say ECreek) by going to a wider tyre (say 185 to 205) if weight was not considered?

Unless you're a total pro, I don't think you'd notice the difference in wheels. Best Motoring did a test once where they took a car, did some timed laps, and then changed the wheels/tyres to a bigger size. They has a few 10th improvement over 30sec lap.

Going by that you're looking at around 1/2sec around EC ... that is if you can be that consistant and are no longer improving due to the improvements in skill.

On the other hand, I've seen a mag compare the same car with different 'type' of tyres. Even between the different road tyres there was about 1sec difference over ~60sec lap. Then they put on R-spec tyres and went another 1.5sec quicker.

I'd say you should notice difference in tyres on the track ... even between different road tyres.

cashout

I just checked the P1s in 15" and they only weigh 4.6 KGs each... that is a whopping 10Kg lighter than the stock wheels on the smart (although I don't know if the provided weight of the stocks is with tyres on). That is 40KG lighter on the P1s.

So where do I get a set of $5 P1s??? :-) :-)