Great information Tony.

Do you happen to know the weights of those 3 wheels that you used in your test?

Here's a scenario I've always been interested in:

Let's assume Wheel A (tires included) is a 19" wheel that weighs 48 lbs. And Wheel B is a 17" wheel that weighs exactly the same. Both wheels have the same diameter (i.e. 26" tall). Would these 2 wheels have any differences in terms of performance?

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If the material and width of the rims are identical then based on simple physics the outward force based on the same rotational speed would be greater with the 19" since more weight will be closer to the perimeter. The calculation I am no too sure of is when the weight is sprung how much more force is required for every additional lbs added to the wheels. There is definitely an impact but I'm curious whether that relationship is linear or exponential as rotational speed increases. Hope Tony can enlighten us on this matter By the way, I will be getting a dyno this week with my original wheels and will update you guys on this.

 

I don't have the weights readily available. I'll need time to dig them up.

But yes, the moment arm of the wheel makes a difference on the acceleration.

 

Thank you. That will make things a bit clearer for me.

I didn't pass my physics course this year. Can you explain this in a different manner?

So assuming that the 19 inch wheel and 17 inch wheel both weight the same and are both, for example, 26 inches tall... will the 17 inch wheel have any significant advantage over the 19 inch?

 

Given the same diameters, the wheel with less weight toward the outside will have better performance.

 

Yes.

 

To add to Tony's answer. You can have the same exact weight and diameter but it really depends on the weight distribution from the center of the rim to the perimeter. If most of the weight is located at the hub then the impact would be less compared to if it were mainly on the tires, but chances are that the 17" will still be better since most of the weight on any rim is at the end.

 

So i just weighed my wheels since I am getting a dyno tomorrow.

Axis Zero Wheels
20" x 10" with 275/30/20 = 54.8lbs

OEM wheels with 2003 6MT
18" x 9" (i think) with 245/45/18 = 48.8lbs

 

Do a pre/post dyno on them.

 

I wish I could do a dyno back to back with the 18" then the 20" but since the wheels are so big, I'll have to compare it to last weeks dyno with the 20". Hope the variations won't be bad.

 

The results will be a little iffy but its better than nothing.

 

Yeah, i hate to have this variation as well. I should try to see if my 18" can fit in teh back seat.

 

You probably can. You will only need the rear tires.

 

Per your request I have resolved the issue Just unmounted my 18", put the 20" back on and then put the 18" in the trunk and back seat! Pheww, that was tiring. I hope this will make those HFCs and TPs you are making come to market faster

 

they can put one in the trunk and one in the back fold down the seat. I put all 4 of my 20's in my car when I bought them from Rookie.