[Lotus F1]

OK, So exactly how are we going to get these awesome light weight wheels for our Saffron Yellow Elise. Anyone have any connections or ideas. These wheels are all that seperate me from my dream car . We have a few months lead time to get them for the arrival of our beloved Federal Elise.

 

[LarryB]

Pretty sure the Fed Elise is going to a 5 bolt pattern rear wheels. So we'd have to confirm that & the pattern, then find out if the KMS are available in that configuration. Then work on getting them over here.

 

[Arno]

Pretty sure the Fed Elise is going to a 5 bolt pattern rear wheels.

Personally I'd think that's unlikely.

Its either going to have 4 or 5 bolt all round.

'Mixed' bolt patterns are just too much of a hassle and it looks very weird on the car.

The test mules for the Toyota engine used the rear hubs from the VX220/Speedster which has 5-bolt wheels, but you can't really determine anything from these 'cars'.

They are just put together from random bits that fit to perform specfic tests (in this case evaluating engines)

Bye, Arno.

 

[LarryB]

Wouldn't want to drop lots of money on nice light-weight wheels till I'm sure they would fit... was my only point.

 

[Joetz]

Anyone know how much these wheels weigh vs. the stock wheels?

 

[LarryB]

Posted this earlier, the KMS aren't cheap.Think it was close to $3k for a set.

The spec that I came across:

111S Wheel
Front:
111s front--------15.17 lbs (6.88kg)
Rear:
111s rear---------20.94 lbs (9.50kg)


OZ Wheel
Front:
OZ front----------14.11 lbs (6.4kg)

Rear:
OZ rear-----------21.6 lbs (9.6kg)


KMS wheel Japan
Front:
KMS fromt----------10.14 lbs (4.6kg)

Rear:
KMS rear-----------11.9 lbs (5.4kg)

Considering the OZ are wider in front then the std wheels, it's not bad.

 

[FederalElise]

why not use this, it's heat resistant

 

[Derek]

Those Black with chrome wheels look great. $3k is a bit pricey for my taste. I'll make do with my gun-metal eight spokes.

 

[babak]

No offense guys, but I'm curious...Looks I can understand, is 30lbs total wt difference that important to non professional racing? Or does the change in wheel wt make a huge difference elsewhere aside from total wt?

 

[LarryB]

A change in unsprung weight means a 3-4x change in sprung weight, in this case 90-120 lbs.

 

[ConeFusion]

A change in unsprung weight means a 3-4x change in sprung weight

I keep seeing these numbers, and sometimes even higher ones. Where do they come from? Unless I see a theory or measurements behind them, I'll believe that somebody made them up, and everybody repeats them. I did the calculation (I can dig out the post from another message board), and the factor for the effect on acceleration came out as less than 2.0, 1.5 is a more realistic estimate.

 

[smoseley]

babak,

Think of it this way: the wheels are not only weight that has to be propelled forward, but they require an additional force to get them spinning. The rear wheels iirc (on a RWD car) have the added inertial dampening to the axle.

Not sure what the final math works out to, but LarryB's calculations seem pretty right on. Losing 30 pounds in your wheels is like 120 elsewhere.

 

[smoseley]

I did the calculation (I can dig out the post from another message board), and the factor for the effect on acceleration came out as less than 2.0, 1.5 is a more realistic estimate.

Could you post your calculations? I'd be interested in seeing the math.

 

[smoseley]

By the way, count me in for those KMS rims !!!!

 

[FederalElise]

yup, the wheel it has to build up momentum for it to spin, and light set of wheels is not only for looks but for performance. Not to mention the bulk of weight of wheels is on the outerside, affecting further more. (being momentum = weight * distance)

 

[L8BRAKR]

Babak, wheels and brakes are definately the best place to lose weight. They are unsprung and rotational. I'm not a math wiz to give formulas and calculations but I do know the effects will be much greater than losing the same amount of "other" weight. If I remember correctly you ride streetbikes and if you have ever been on a bike with marchesinis' or some OZ's they definately feel faster and change direction quicker. If the wheels have less inertia the turn-in will be sharper and you can accelerate and brake them with less work done.

 

[ChrisB]

Equally important, unless you are driving on a glass-smooth road, is the affect unsprung weight has on handling. The ability to keep the wheels in uniform contact with the road surface and the chassis stable, is very directly related to the ratio of the sprung to unsprung weight (the car : wheels, tires, etc.). Proper shock valving is crucial to that, but can't overcome the inertia that a heavy wheel will impart into the chassis when hitting a bump.

For a road car, that also translates into a car that both handles very well and has a compliant-feeling ride.

 

[LarryB]

Yeah, guess I should have said in effect. As ChrisB has hit on it's as much about the change in handling/ride as well as the rotational mass.

 

[ConeFusion]

I know that there's an effect on handling. I'm certainly not smart enough to calculate that, if it's even possible. That's why I talked about the effect on acceleration. My calculations are in the moderately long post with formula around the middle of this thread:

http://www.solo2.org/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=7;t=000301

 

[smoseley]

"Unsprung" Weight

In fact, why wouldn't the weight of your axle, driveshaft, and flywheel affect your power?