question about rims...

[andylawcc]

How does the a) Size/Radius, b) Mass/weight of the Rim affect the car's overall performance?

from my basic physics knowledge, the larger the radius, more torque will result. while increasing the mass will increase the inertia... to transulate to english, it means the bigger the rims, the faster the car will be but require more initial input.

please correct me...


ADD:

anyone know where can I buy the lightest rims that actually look cool?

 

[Pastore]

although theoretically the bigger the rim, the more power the car would have, is it actually a noticably difference?

 

[toph99]

if i remember correctly, the lighter the rims(aluminum over iron) the lighter the car(obviously) and the faster stopping time because of the lessened momentum. also, it would take less power to get them moving, so lighter is better

 

[Fingers]

the bigger they are doesn't really matter, because the size of the tire wall will make up for the difference. weight will have only marginal affect when you consider that the rims are very light compared to the 1 (+)? ton vehicle

 

[Viperoni]

Actually, unless you don't want to mess around with your speedo, you'd be better off with sticking with the same overall diameter. The rim size won't make any difference in that way, but the lighter the rim is, the less unsprung weight, and hence increased handling as a result.

 

[Viperoni]

<< weight will have only marginal affect >>



You have to take into great consideration that the wheel/suspension weights is unsprung weight, not being supported by the springs/shocks.
ANYTHING that can lessen that weight will help in handling.

 

[TuffGuy]

actually, the diameter of the tire+rim stays the same. as the rim diameter increase, the height of the tire wall decreases therefore increasing structural rigidity. as a result, you can go faster and be more stable, both in straightways and in turns.

also, keep in mind that chromed wheels are the heaviest. not what is desired on a FAST sports car.

i think...

 

[yakko]

The weight of the wheel as well as the placement of that weight will have an effect. With a wheel you have rotational weight which increases with speed. In theroy you want your wheels to weigh less and have the majority of the weight near the center of the wheel.

 

[toph99]

and don't forget, that with big rims you tend to have smaller tirewalls(i can't remember what it's called, like a 45 vs. a 70, some sort of ratio with the tirewall size:rim diameter) and it will decrease tire-roll(i believe that's what it's called) and help turning

i could be wrong

 

[andylawcc]

anyone know where can I buy the lightest rims that actually look cool?

 

[Fingers]

but keep in mind that the car has the wheel trapped between it and the ground. for example try piviting when there is a fat man sitting on your back.

 

[Viperoni]

A lot of the alloy are light. Don't get the chromed ones, they indeed are VERY heavy.
Too bad I can't but any on my land yatch....probably snap them in half in a corner

 

[jimmygates]

Racing Harts are light and look nice . Big rims can also throw off the speedometer by 1-3mphs




-jimbo

 

[TuffGuy]

andy, try this place. konigs and enkeis are pretty cool.

 

[andylawcc]

oh god.. racing harts... that's what my friend has on his eclipse... I have no clue about modding cars but my friend always talks about it, so it somewhat grabbed my attention (and hopefully not my money)... Blitz, Hammon... and my personal favorite is Antera... they are sweet.

 

[Sluggo]

Only the overall diameter of the tire will have a difference on the speedometer, or effectively reducing or increasing the final drive ratio. Taller than stock will raise the final drive ratio, basically making it seem like the rearend gears are higher (lower numerically). For instance a 4x4 pickup that has 31&quot; tires and a 3.73 rear end gear stock, then you get maybe 36&quot; tires, you would need get lower rear end gears to maybe 4.10 gears (higher numerically) to compensate for the taller tires and maintain the stock accelaration, and engine work load. there is a whole big formula to help figure all the exact numbers, but I do not know it.

The most popular thing going on these days is known as plus sizing your tires &amp; rims. Basically you try to maintain the overall tire diameter, by buying tires with a shorter sidewall as you move up in rim size. For instance your car comes with 15&quot; rims and tires with a 6&quot; tall sidewall.

Plus 1 16&quot; rims 4&quot; tall sidewall

Plus 2 17&quot; rims 2&quot; tall sidewall

plus 3 18&quot; rims 1&quot; tall sidewall

Please dont hold me to the rim sizes and sidewall heights, it is only to demonstrate what is going on.

The most fascinating thing I have ever read concerning tires is this: Say you are traveling 50 mph, at the moment of contact with the pavement your tire is traveling 0 mph, since it provides the point of contact. To make up for this, the top of the tire travels at 100mph, but the front and back edges of the tire only travel at 50mph, think about that for awhile.

 

[Soybomb]

<< weight will have only marginal affect when you consider that the rim >>


Wrong, unsprung weight has even more of an effect on performance then weight the suspsneion is supporting. Would you notice it much on your street car? not unless you're going from like 80 to 40 pound assemblies most likely.....at the track though you might very well see a small difference.

 

[SuperGroove]

Okay...let's see

Lower the sidewall, rougher the ride, but increases grip

The wider the tire, increases grip

A larger diameter wheel, often increases grip, at the expense of ride quality. Larger diameter wheels are often heavy. More weight=more WEIGHT!! There's a reason why auto crossers don't auto cross with 18&quot; rims. Larger wheels also affect the accuracy of speedos

As for wheels, Volk TE-37s look nice and BBS wheels are often the best compromise of looks and weight. BBS wheels are often the most expensive, however.

I am NOT an expert on wheels. The TireRack is.

 

[NOendINsight]

if you want cheap, decent looks, and light weight.

try rage race 10's last i knew they were 75 bucks on tire rack, and they weigh in at 14 pounds for a 15 inch rim. Not sure if they still are, but they were the lightest rim that tire rack sold.

Me ive got 16x7 focal r3's and 215 40 16 kumho's

NOend

 

[Angrymarshmello]

The lighter the rim the better - use your stock rims and put it into neutral (in a stick) and you can feel the car slow down - using light light rims, the car slows down a lot slower

 

[mechBgon]

When your car accelerates, it must accelerate all its mass forward linearly. Things that rotate must also be accelerated rotationally. Your car's top static speed is not going to be different due to heavier wheels. The additional rotational moment, howver, will cause it to accelerate slower. Additionally, the closer the mass is to the outside edge of the wheel, the more influence it will have, since rotational moment is related to the square of the radius. This is why a hoop will roll down a ramp slower than a disc of the same size and weight... all the mass is at the outside edge.

Larger outside diameter will also effectively give your car taller gearing.

Being a bicyclist, I'm very attuned to the rotating-weight issue. When you're the engine, every ounce matters.