Wheel Size Versus Handling?

[LifesHarlequin]

Which wheel and tire combination offers the best handling? From the basics of what I can find, the larger the wheels, the better cruising is, but if going for handling and road carving, I've seen a lot of mix between 17" and 18" wheels.

Has anyone done any testing or have any experience of which would be best for which application on a Sportster?

[LifesHarlequin]

Seems like all the Buells run with 120/70/17 front and 180/55/17 rear tires. Anyone installed a set of buell wheels on their Sportster and noticed a difference in flickability?

[toe]

The wider tires are better for cornering power.

Narrow tires make your bike feel more nimble

[Albie1200]

I was once told a taller wheel will resist leaning to the side due to gyroscopic effects. If it is true a bike with 17" wheels will enter a turn easier than a bike with 21" (front). Of course this is hearsay and I never claimed to be a physics major, so there is a good chance I am wrong.

[stealthammer]

The stickiest tires are usually only available in 17" (front/rear) and a few 18" (rear) these days. There is nothing really sticky is made in 21", only a few in 19". If you are going the really carve 17" is the way to go, but a 19" front and 18" rear is a distant second best choice. If you want the best handling you have to start at the tire, not the wheel size.

[88inchsporty]

I run radials. 120/60-17 front, and a 150/70-17 rear. Flickability is outstanding,as are all aspects of ride and handling. Responds quicker to rider inputs than my Buell X-1.

[Moved On / My Own Choice]

I think generalizations can be dangerous - you have to consider not only tire size, but construction/profile - radial vs. bia-ply for instance...

[LifesHarlequin]

I'm looking at getting a set of custom 40 spoke wheels (17x3.5 front and 17x5.5 rear) covered in Pirelli Diablo Strada tires (120/70 and 180/55),which is the same as the Buell. Can anyone see any problems with ride height or angle change? I know the height will be lower, and the wheel base slightly shorter, but with the angle being tilted downward toward the front, would this increase or decrease handling?

I know on cars, with the front in still in a dive, the car will handle lousy through a corner as the weight balance will be mostly on the front tires, which will cause understeer.. does this hold true for a motorcycle?

If so, how would I correct this? Lower the rear end via shock setup?

[Brian73]

Originally Posted by toe

The wider tires are better for cornering power.

Narrow tires make your bike feel more nimble

Narrower tires make your bike more nimble. For best cornering capability, in theory, you want your tires to only be as wide as they need to be to get the power to the ground without slipping. 250 cc 2-stroke bikes out-corner liter bikes on a road course while running only 150mm rear tires.

And, like Kev M said, width is only part of the equation.

[LifesHarlequin]

The Diablo Strada's are radial tires, and the 180 seems about the right size.. I'm more worried about the change in bike profile and how it will affect handling.