The extra weight could slow you down but you just have to decide if you want to look good or take a little power hit ..... if your going to run it at the track every w.e. i wouldnt put 20s on but if your just an occasional dragger then go ahead and slap them on it wont be a huge difference
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my 20" wheels & tire combo weighs 11 lbs more per wheel, I know because a friend loaned me his stock wheel & tires when I took one of mine in to the chrome shop for replating. While we had the 1st wheel off we weighed it and found the difference - don't remember the exact weight, just that the 20's were 11 lbs heavier Don't care though, this isn't a racecar, its a streetrod that is as much about looks as performance and just plain old old fashion streetfun
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2006 Roush convertable Stage "X" Whipple HO polished SC 460 RWHP & 433 RWTQ 14" drilled & slotted Wilwood brakes 4 wheels Roush Suspension - Steeda extras B&M shifter CHE K-member Torque Limiter 20" wheels SLP Longtubes & X Pipe w Hi
20's Hurt you performance because: 1. There is less sidewall to actually bend during launches so that the tire doesn't put all the power in one woop to the ground but a more progressive (Look at a dragster wheel, the rim turns almost 1/2 way before the tire starts moving) 2. Most 20's are made for looks and not performance thus they tend to weight more which this in turn means more rotational weight and approx 1lb rotational = 4lb regular weight 3. Since they have less sidewall and tend to weight more and have a bigger radius that means the weight is more concentrated farther from the center of the wheel which this in turns makes it harder to turn.
I am trying to get a friend of mine to our local dyno to prove the actual hp loss on stock 17's vs 20's. Of course I am gonna weight his 20's so you guys get an idea of the 20's weight.
Att. Andrew
I agree with some of what you are saying about weight and sidewall flex but the radius on the tires will remain the same. Thats why you have a small sidewall. I think the weight thing plays an important roll in performance and the fact the 20" combo does weigh much more than 17's or 18's does rob power but so does a full tank of fuel and passengers. Just have to pick your battles.
We are talking about power loss on 20's were do passengers and full tank comes into play? Also Norty erm.... You ok over there??
I think the weight thing plays an important roll in performance and the fact the 20" combo does weigh much more than 17's or 18's does rob power but so does a full tank of fuel and passengers. Just have to pick your battles.
It's not the same kind of weight. The engine doesn't have to turn the fuel tank or your passengers.
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I think the weight thing plays an important roll in performance and the fact the 20" combo does weigh much more than 17's or 18's does rob power but so does a full tank of fuel and passengers. Just have to pick your battles.
It's not the same kind of weight. The engine doesn't have to turn the fuel tank or your passengers.
the increase in gravitational weight is minimally significant, tho present. you are right that the rotational weight increase is what the main issue is with bigger wheels.
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I agree with some of what you are saying about weight and sidewall flex but the radius on the tires will remain the same. Thats why you have a small sidewall. I think the weight thing plays an important roll in performance and the fact the 20" combo does weigh much more than 17's or 18's does rob power but so does a full tank of fuel and passengers. Just have to pick your battles.
He's not talking about the radius of the tire where it contacts the road. He's talking about the radius of the wheel itself.
Wheel weight isn't the whole story. The real problem is the INERTIA of the wheel. Inertia is calculated by integrating mass times radius over the entire wheel. Remember calculus class back in school?
Anyway, the point is that if you have two rotating objects of identical weight, but one of them is larger in diameter than the other one, the one with larger diameter has more inertia. This is a classic phyics demonstration that you might have seen in school: a larger hollow ring has more inertia than a solid disc, even though both weigh the same.
In other words, suppose you had two wheels, both of which weigh exactly 25 lbs on a scale. Their designs are identical except for the diameter: one of them is an 18" wheel and the other is a 20" wheel. The 20" wheel has more inertia becasue it has a larger radius, despite the fact that their weights are identical. More inertia = bad for performance.
Not only do most 20s weigh more than the smaller wheels, but they also carry the bulk of that weight at a larger radius than their smaller counterparts. Thus even if the 20" wheel weighs the same as the smaller wheel, it's inertia will still be higher simply becasue it is larger.
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RE: Power loss with 20's? here we go again! - 
