Tire Question

[mister]

110 front
140 rear (cause they didn't have any 130 in stock)

Michael

[Phil B]

Now about the "front wheel does the turning"....hmmm.....then how do I turn on my unicycle???  (or doing a wheelie on my bike??)

Cookie

Those are silly, yet related questions.

on a unicycle, "the" wheel is, literally and logically, the front wheel.
Just like an only child, is also "the oldest child", "the favourite child", etc, etc.

if you do a wheelie, then you turn your moto into a unicycle, that just happens to have a useless circular appendage in the upper regions.

[burning1]

In empirical testing, it was demonstrated that a wider tire would produce *slightly* more grip than a narrow tire; we're talking a few percentage points for going from a 160 to a 180. For a racer a few percentage points is huge, since it can mean a second/lap difference. To the street rider, not so much. Tire compound has a significantly greater impact on traction.

See Motorcycle Dynamics by Vittore Cossalter for details.

In practice, there are some significant downsides to running too wide a tire, especially when we're talking about the massive 300mm+ ones seen on some cruiser bikes.

Larger tires are heavier, which means less un-sprung weight, more rotational inertia, and more gyroscopic resistance to turn in. The profile can be a little flatter, which also creates resistance to turn in (was a major issue with early 190/50/17 tires.)

In general, 110/70/17 & 140/70/17 profiles seem to work extremely well on the GS500. You can run a 150 rear bias ply tire on the GS, but I'd recommend running a radial larger than 140. For race use, a number of manufacturers make 110 fronts. The BT003RS rear tire works extremely well on this bike, and plays nicely with the fronts from other brands. Pirelli is also working on a Diablo Rosso 2 tire in those sizes; Brian Bartlow was testing it out this weekend at Sears Point.

For race use, we sometimes install larger rims because we want more tire options. For street riders, it's a non issue; there are tonnes of good street tires designed to fit the stock rims.

In general, I'd suggest not trying to 2nd guess the engineers that designed the bikes. Modding can be fun, but usually impractical.

[scratch]

Give me skinny tires in the rain!

I'm currently running the Avon RoadRunners in 110/70 and 130/70 for the quick turning, chassis attitude and bottom end (without the sprocket change).  Great for the Rain!

[twocool]

Let's face it...most guys are putting on bigger tires because they think it "looks cool".

In USA the motto (for everything) is always "bigger is better" and the "bigger the better"

When you ask "why", you dont' get good answers, except,   "It has to be better, It's bigger!"

My motto is "better is better"..........

Throuble is with most things there is always a trade off......better in one respect and not better in another.....so you have to compromise.

But it is a free country..so if you want fat tires...get fat tires......at least you'll "look" cool.


Cookie