How does spacing a wheel further from its center line hurt vehicle accelration?

[Agent WD-40]

I read this in an article that was discussing the pros and cons of plus sizing your tires. It said that even though it looks cool to have your wheel and tire pushed out further from the wheel center it causes the tire to resist spinning, just like adding mass to the wheel and tire setup will cause the tire to resist spinning thus hurting acceleration and braking. Why is this so? I understand how the added mass will have this affect but not how moving the wheel/tire further form center line will do this. Anybody know why? Thanks.

[DevinSixtySeven]

what mag? got a link, or an article reference? it shouldnt make a difference unless youre changing the mass distribution in the radial direction. the axial direction shouldnt matter at all, unless the tire/axle/rim is very floppy, which it hopefully isn't .

-s

[Sumo99]

Maybe when they said "plus sizing" they meant wider tires. Wider tires will resist spinning because there is more surface contact (friction). Just a thought.

[DJ]

To get such a configuration, you might have to use a heavier or a lighter wheel, or a wheel with a different weight distribution. The axial relocation of the center of mass would have no effect, but the different rotational inertia would.

The biggest effect is the ENORMOUS change in the relationship between the forces the wheel generates and the steering components. It puts a hellish strain on ball joints and tie rod ends. Can you say, "steering instability"?

[Agent WD-40]

It was in an article in this months (mat 2004) Motor Trend called Hey There, Big Wheel. I will type a bit of the article out here, perhaps I miss read it. As I'm understanding this it didn't make much sense so that is why I posted.

"Acceleration requires turning the rolling stock, too, so we must also include their rotational inertias. Here, the 23-inch wheel's big rim- spaced a crucial 2.5 inches farther from the wheel center- takes a second bite out of acceleration. We won't go into how we went about measuring this, but their added reluctance to spin is equivalent to four times the increase in wheel and tire mass."

[DevinSixtySeven]

i'm reading that as 2.5" away in the radial direction...what dj's first paragraph says. a larger rim will only help if the weight of the rim is less than the weight of the tire that would otherwise occupy the space...hard to weigh less than air and a couple strips of rubber.

-s

[Agent WD-40]

Ok, I'm savvy now. I just misread that. It makes much more sense now.

[ThomasE]

I've always wondered when increasing wheel size but same overall tire diameter does the weight increase, generally speaking. For example, 31x10.5x15, 265/70/16, 265/65/17 are all the same diameter and width. Assuming similar type of tires and wheels which is lightest to heaviest?

[DevinSixtySeven]

the smaller rim size will be lightest, in general...if you kept the mass distribution of the 15" wheel and tire same as the 17" wheel and tire, the 17" wheel would be very weak to say the least. air weighs less than aluminum ...

i seriously doubt there are many exceptions to this, but i'm sure there are 17" rims which are lighter than 15" rims *of a different model*...but the 15" will always be lighter than its 17" counterpart, obviously.

-s