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Do bigger rims really hurt performance?


jjs316

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Do bigger rims (18s,19s,20s) really hurt your performance that much? Ive heard people say they do but some say they shouldnt because with the bigger rim and the lower profile tire it is about the same size as the stock rims with the bigger tires...this true? Thanks

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yea the bigger the tire the less torque you have there for the slower you go it is harder to get the big wheels/tires going

 

handling will be inproved if you get the right combo with your suspension

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A bigger wheel is going to give you taller gearing which means less low end but more top end. Bigger wheels usually mean heavier wheels though. And since it is weight on the wheels it is rotaing mass, and rotating mass is like 10X more then weight in your car so if your wheels weigh 1lb more than the stock wheels you are adding 10lbs to the car. If they weigh 5 lbs. more it is like adding 50lbs to the car. etc.... I don't know if 10X is te actual difference but it is crazy. A bigger, heavier wheel will slow you down.

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A bigger wheel is going to give you taller gearing which means less low end but more top end. Bigger wheels usually mean heavier wheels though. And since it is weight on the wheels it is rotaing mass, and rotating mass is like 10X more then weight in your car so if your wheels weigh 1lb more than the stock wheels you are adding 10lbs to the car. If they weigh 5 lbs. more it is like adding 50lbs to the car. etc.... I don't know if 10X is te actual difference but it is crazy. A bigger, heavier wheel will slow you down.

 

Bingo! Physics is fun!

More inertia, therefore more force to get it up to a desired rotating speed.

 

- Erik

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but then again it also depends on what the wheels are made out of and what the pattern is, because yeah some wheels are heavy as hell but then you have other wheels that are cut alot and there isnt as much materual there to add weight, but overall, yeah, the bigger the wheel the heavier it is with very few exceptions. but if you get a bigger rim and a lower profile tire to match the size i dont see how that would slow you down any, just the idea of more weight, thats all i can think of. lets say you have a 15 inch rim with 8 inches of rubber around it (think 4 inches on top, 4 inches on bottom) i know thats not real but im just using it as an example. lets say you go with a 17 inch rim, thats 2 inches wider than the 15 inch rim, then you just get smaller profile tires (23 inches tall with original tires) so youll have a 17 inch rim with 6 inches of rubber (3 top, 3 bottom) 17+6 equals 23, same size as before, all the ratios should be the same

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Rim size has nothing to do with gear ratio in any way, the tire size does. It also doesn't matter how much the wheel weights but how far off center that weight is. A 16lb 16" wheel is much easier to turn then a 16lb 18" wheel because the weight is closer to the center and therefore takes less torque to turn.

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Also, the majority of a wheel's weight is in the outer diameter, the majority of a tires weight is in its tread. Therefore for the same overall size tire with different sized wheels, the tire itself will have around the same rotational inertia. The wheel though, if you up the size the rotational mass will get moved outward and take more torque to turn.

 

So in otherwords, you can think of the tire as a loose constant, the wheel size does not really effect its rotational mass much, the wheel is what will loose you performance (either that or overly large tire diameters, which is hard to do on a car anyway)

 

FYI, both NASCAR and F1 use 15 or 16" wheels I believe. The larger wheels you see in SCCA? Auto-X and ralley races is to reduce sidewall height and flex.

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i dont think i really lost ne power addin my 20 inch rims with close to stock rubber(my tire is basicaly stock size like 1/8th off) ya it sucks up some low end power but i got hi end gains n wigh my lower suspension my handlin is wicked above average

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i think if you got some light ass 16s and tall tires (say michelin harmony) or something you'd be sitting pretty quick. rubber weighs less than aluminum/chrome/watever right? so if u get small, light wheels, they'll be easy to spin and u won't lose low end torque and the tall tires might help the upper end torque by simulating a bigger tire? i need to sleep be4 i can make any sense

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i think if you got some light ass 16s and tall tires (say michelin harmony) or something you'd be sitting pretty quick. rubber weighs less than aluminum/chrome/watever right? so if u get small, light wheels, they'll be easy to spin and u won't lose low end torque and the tall tires might help the upper end torque by simulating a bigger tire? i need to sleep be4 i can make any sense

 

As long as they are stock sized tall tires, if you oversize the height you'd be loosing power again.

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OLDSMOBEAST!!!! your back, we've missed you :D

 

Thanks phantom....i missed u guys too...but its good to be back!

 

as for the oversize tire=bad thing....yeah u just gotta find the right balance i guess. I got a set of Michelin's Harmony tires to replace my bald XOnes (which they told me they stopped making, even though they're still for sale damn near everywhere.... :roll: ) and they're awesome! a little taller than my old ones, they're all seasons and they have some nice deep tread, they're pretty soft but have a 130,000 KM treadwear warantee, and i just fell in love with them...they changed the whole handling dynamic of the car! I can take curves that used to squeal at 60km/h at like 100 (well actually i only tested that curve up to 80 because i was scared for my life...) without the tires making a single peep...they get amazing grip in the wet and i'm confident they'll do OK in the snow, although i've yet to find out...thank God...I should be a tire salesman....anyway....i'm going to hit the 'gym' (which secretly means i'm gonna chill with a girl or cruise or something while my mom thinks i'm at the gym :twisted: ) then i'm going to hit Maaco to get an estimate on the rust on the car's left quarter panel....the Dealer auto-body shop (the best one around) said about $2500 should do it...but i want other estimates beacause that's a big penny to spend on auto body work, especially when the car might not sell for that price.

 

Later!

YK

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