Brian A wrote:
mk e wrote:
...I noticed it just felt heavy....27lbs. Its 17×8. The 550 front is 18x8.5 and 22lbs. The 18x10.5 is 25lbs. Onshape says the rear 3 pc is 18lbs...
What is the impact of wheel weight on acceleration?
I have read many places were people attribute faster acceleration times to lighter wheels. This doesn't make sense to me since the amount of inertia (linear and angular) of even a heavy wheel are minor compared with the inertia of the weight of the car.
I totally "get" how lighter wheels improve suspension performance. I put lighter wheels on my track car and was amazed at how much I could feel a miniscule weight change in the unsprung weight. … but acceleration? … I felt nothing.
Is it a fallacy that lighter wheels accelerate faster or is it that I just don't understand the physics?
What matters about the wheels (and the brake discs and the tyres), is that it's a
rotational inertia. It's way more important to save 1 kg on a wheel than on any other part of the car that isn't in the drivetrain. AND you want your wheel to be as small as possible, or at least its weight to be the most centered, just like saving 1 kg on the roof is better for handling than saving the same 1 kg in the door sills.
Here's an intuitive demonstration:
http://www.youtube.com/watch?v=CHQOctEvtTYIn some racing series (I think it's the case in formula Vee but I may be mistaken), competitors must use street tyres on their single seaters but have the right to remove thread material (sort of sanding the rubber). It matters because these few hundred grams (of a rotational part and the further appart from it center of rotation) saved are the most beneficial on the whole car.
In the present case, I'm not sure Mark is going to notice any difference. What will be important, though, is maintaining the integrity of the wheel (and thus Mark's integrity) would the car ride on a pothole or need to brake...
Mark, I cannot understand why you're so eager to cut your 550 wheels rather than buy 4 plain barrels (forgive me if that's not the right term) to add your own centers on?
Another idea that hasn't been suggested yet (I think): wire wheels
It's not period correct but I think the 308 could pull it off and they can be made compatible with modern tubeless tyres.
I've even found them in 18" for Ferrari :
https://www.ruoteborrani.com/en/wire-wh ... wheel/79/#