Would going from 18s to 20s slow me down?
#21
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Originally Posted by sleepyca31' post='423649' date='May 12 2007, 10:26 AM
Thanks for the last few posts-that was very helpful. I was totally in the dark about keeping the rotating diameter the same-forgot about lower prof tires and such. And unsprung weight is something I just learned about it-interesting. I was told like you said this really affects acceleration?
This may be way off base but does the same log apply if you REDUCE weight on each corner by 15 pounds-is that like a "600" pound weight loss in terms of acceleration?-if so that would be my next mod considering the Z4 that weighs 400 less seemingly accelerates 1 second faster in the 0-60-sign me up! Unsprung weight-a great find!
This may be way off base but does the same log apply if you REDUCE weight on each corner by 15 pounds-is that like a "600" pound weight loss in terms of acceleration?-if so that would be my next mod considering the Z4 that weighs 400 less seemingly accelerates 1 second faster in the 0-60-sign me up! Unsprung weight-a great find!
#22
Originally Posted by ressla' post='422649' date='May 9 2007, 01:03 PM
Further note : A bigger diameter wheel when matched with lower profile tyres can keep the same rolling circumference as a standard wheel ( also meaning no need to re-calibrate your speedo). BUT generally a bigger wheel is also WIDER and more power is required to move the car due to increased surface area in touch with the road.
So short answer YES acceleration will decrease slightly,but generally this is not noticeable to most drivers.Plus you will benefit from better handling on the low-pros.
So short answer YES acceleration will decrease slightly,but generally this is not noticeable to most drivers.Plus you will benefit from better handling on the low-pros.
actually, the contact patch has nothing to do with it
inertia is the word.. basically, as weight is put further away from the center of any spinning object, it takes more energy (torque in this case) to affect its angular acceleration.
generally, unless you have like 21" magnesiums, yes, you will feel slightly slower (acceleration and brake wise)
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The wheel weight issue wont have much affect on a big heavy car like the 5.
You'd feel it in a light weight racer maybe but not in a big well powered saloon.
Id really just concentrate on getting the right size tyres to keep the overall rolling circumference the same.
You'd feel it in a light weight racer maybe but not in a big well powered saloon.
Id really just concentrate on getting the right size tyres to keep the overall rolling circumference the same.
#24
Originally Posted by Aeroresh' post='423930' date='May 13 2007, 09:52 AM
The wheel weight issue wont have much affect on a big heavy car like the 5.
You'd feel it in a light weight racer maybe but not in a big well powered saloon.
Id really just concentrate on getting the right size tyres to keep the overall rolling circumference the same.
You'd feel it in a light weight racer maybe but not in a big well powered saloon.
Id really just concentrate on getting the right size tyres to keep the overall rolling circumference the same.
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Originally Posted by sleepyca31' post='423945' date='May 13 2007, 07:16 PM
The 530 is not ALL that heavy-It weighs less than the 335 and the same as the 328 which I would consider smaller cars-so I wouldnt be surprised if it was more noticable than people think-For a pretty big sedan they kept the weight one of the lowest in their entire set of cars-only the Z series is lighter and 3 series is the same or heavier (335)-obviously the 535 is now heavier than the 335 but that is the engine but 530 was actually quite light at 3400 for the size of the thing.
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Interesting topic on wheel weights.
I don't think I notice a difference when I go from 17" to 19", but then I do have light weighted wheels (about 8-10 lbs lighter at each corner).
However I don't notice too much of a difference in acceleration, maybe slightly faster with the new wheels? It seems to move more freely when I step on the gas...
Maybe my 19" has more weights on the outer edge than my 17", and the overall effect is the same (or slightly faster with my 19" light weight wheels)?
Since I have a 525i, I am more concerned with weights and wouldn't want to add heavy 19" wheels to my car, although many people have style 166 and haven't heard them complaining, so the effect shouldn't be too noticeable. For reference, I think the style 166 is about 26-27lbs? Style 124 is quite heavy for 18" wheels (~30lbs). I also think having wider tires may mean a little more rolling friction that may affect acceleration? Light weight 19 will be in the 20-21 lb range?
I don't think I notice a difference when I go from 17" to 19", but then I do have light weighted wheels (about 8-10 lbs lighter at each corner).
However I don't notice too much of a difference in acceleration, maybe slightly faster with the new wheels? It seems to move more freely when I step on the gas...
Maybe my 19" has more weights on the outer edge than my 17", and the overall effect is the same (or slightly faster with my 19" light weight wheels)?
Since I have a 525i, I am more concerned with weights and wouldn't want to add heavy 19" wheels to my car, although many people have style 166 and haven't heard them complaining, so the effect shouldn't be too noticeable. For reference, I think the style 166 is about 26-27lbs? Style 124 is quite heavy for 18" wheels (~30lbs). I also think having wider tires may mean a little more rolling friction that may affect acceleration? Light weight 19 will be in the 20-21 lb range?
#27
I switched from 18's to 20's last week and I can definitely feel a slight difference from a dead stop. Nothing major, but perhaps with a 530 it may be more noticeable. Unless you're racing your car, it's worth the difference b/c you make up for it in overall ride and performance.
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Originally Posted by marc545i' post='424434' date='May 14 2007, 10:07 PM
I switched from 18's to 20's last week and I can definitely feel a slight difference from a dead stop. Nothing major, but perhaps with a 530 it may be more noticeable. Unless you're racing your car, it's worth the difference b/c you make up for it in overall ride and performance.
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