Installed some Pirelli Sport Demons

[SES2009]

I must say from the short test ride I did after the install the tires don't feel as spongy as the stock ICR's... Also, the road feedback way different than i was used too, i feel a lot more... Im going to do a thurough break in before I really test them out but so far I am really happy with the Sport Demons... This board was instrumental in helping me pick these out and kkim's DIY on how to change the tires was awesome.

I went with 110/70/17 front and 140/70/17 rear

[Sicafied]

Does the bigger rear tire affect performance or is it just for looks?

[Snake]

Pirelli Sport Demons are the only tires I run on my bike and I love them.

[SES2009]

Originally Posted by Sicafied

Does the bigger rear tire affect performance or is it just for looks?

It's purely for looks and from what I read it will make the bike "less flickable".... The 140 is within specs to mount on the original rim and won't pinch the tire.

[greg737]

Does the bigger rear tire affect performance or is it just for looks?

The weight of a tire (in this case the Demon) affects a vehicle in several ways: Unsprung weight, Rotational weight, Total weight, and (unrelated to weight) Overall gearing.

First is "unsprung" weight, which affects suspension performance and is the most complex issue. With no other changes to suspension geometry and damping, more unsprung wieght will negatively affect the suspension's "bump following" ability because the increased mass has more inertia. This is why the designers of racing cars and motorcycles strive for lightness in suspension parts, wheels and tires. A good example of the complexity of this situation is to note the effect of unsprung weight in the interrelations between tires (their weight and bump absorbing ability) and the mass (weight) of the other suspension parts (in total), because it actually creates a "suspension-within-a-suspension" phenomena. This applies to the heavier Sport Demon rear tire because it's extra weight won't accelerate as quickly because of it's greater mass (more mass equals more inertia), but this larger diameter tire itself may have more bump-absorbing ability than the original equipment sized tire, so it's very hard to say what the overall effect it will have on the bike's feel.

Second is "rotating mass" which is easier to understand than unsprung weight because it is simple to see that "more is bad." Any weight added to the bike obviously means less performance, but weight added to any rotating part of the drivetrain not only has to be carried along for the ride, it also has to be accelerated by the engine (i.e. rotated as a means of power transfer) which uses horsepower that could otherwise (in the absense of the extra added rotational weight of the larger Sport Demon rear tire) have been put toward accelerating the vehicle (your EX-250).

Third, which I've already mentioned, is "total vehicle weight." The Sport Demon rear weighs more because it's a larger tire, so it adds to the bike's all-up weight. For any given horsepower, more weight equals less acceleration (damn the inertia, Sir Issac Newton sux! or, did you buy special inertia-free Sport Demons?).

And Forth, an effect unrelated to weight, is that the larger diameter of the Sport Demon affects the overall gearing of the bike's drivetrain. So assuming the bike's horsepower is the same as it was with the old (smaller diameter) tires, the resulting longer gearing will cause slower acceleration. It's the same as changing to a larger front or rear sprocket which lowers RPM at any cruising speed but reduces the bikes ability to accelerate.

So yeah, "less flickable" is correct.

[Jinx250]

Originally Posted by Sicafied

Does the bigger rear tire affect performance or is it just for looks?

Looks / ego. Mostly seems to bother people who have 250s and 650s (not counting the folks who put a *real* wide tire (like a 240) on their bikes. Your bike takes a 130? gotta squeeze on a 140, or maybe a 150. Bike takes a 160, let's see if we can't get a 190 on there. But hey, to each their own, right.

[greg737]

bigger is better.

more cowbell is better.

[Alex]

[Boom King]

I got a fever...

[ducducgooseit]

gotta have more cowbell