17" vs 18" wheels

[gatch]

I realize there must be a reason for 17" wheels being preferred over 18" on bike. All the manufacturers seems to favor them. I imagine it would have something to do with gyroscopic effect, less rotating mass etc.

My question is, how much better ? I mean If I could get my hands on some nice light 18" rims/race tires, would they be comparable to say the heavy standard alloy rims with a race slick ?

Just spit-balling here, no money is being changed hands etc. Just trying to explore my options for a bucket racer..

[Biggles08]

I realize there must be a reason for 17" wheels being preferred over 18" on bike. All the manufacturers seems to favor them. I imagine it would have something to do with gyroscopic effect, less rotating mass etc.

My question is, how much better ? I mean If I could get my hands on some nice light 18" rims/race tires, would they be comparable to say the heavy standard alloy rims with a race slick ?

Just spit-balling here, no money is being changed hands etc. Just trying to explore my options for a bucket racer..

Changing the wheels on any bike makes a massive difference to the way the bike performs, in many areas such as acceleration, braking, and side to side transitions. By reducing the overall diameter of a wheel you reduce the unsprung mass and perhaps more importantly where that unsprung mass "acts" on the wheel. You notice that motogp bikes use a 16.5" wheel partly for this reason.

No matter how light you made the 18" wheel it still would not perform as well as a lightened 17" wheel due to:
a) more unsprung weight and
b) where that weight is situated in the wheel (further out from the center)

Here is some reading about the benefits of reducing your bikes unsprung weight here (http://www.forged-wheel.com/About.htm) from CARROZZERIA (a plug for my sponsor :innocent:)

[mouldy]

I realize there must be a reason for 17" wheels being preferred over 18" on bike. All the manufacturers seems to favor them. I imagine it would have something to do with gyroscopic effect, less rotating mass etc.

My question is, how much better ? I mean If I could get my hands on some nice light 18" rims/race tires, would they be comparable to say the heavy standard alloy rims with a race slick ?

Just spit-balling here, no money is being changed hands etc. Just trying to explore my options for a bucket racer..
You'll be pushing shit uphill trying to find 18" slicks . Try and get a set of rs125 wheels for it .

[gatch]

You'll be pushing shit uphill trying to find 18" slicks . Try and get a set of rs125 wheels for it .

Got any rs125 wheels I can have ?

Nar I wasn't thinking 18" slicks.. There is however a range of tires suited to for 18" rims in race soft compound, like the avons and heidenau used by the classics dudes..