Confused about Wheel sizes

aodhu

Ok,
So I thought I was begining to get the hang of Wheel sizes, I know that mtb wheels are different sizes to road bikes, and you can get 700C and 650C wheels for a road bike. 650C being slightly older with faster acceleration. 700C being the current standard and easier to keep at speed once you get up to speed.

But while looking on ebay I saw the following measurements for road bike wheels:

700 x 23C
700 x 20
:eek:


Can anyone tell me what this means??
Cheers.

Morgan

The second figure refers to the width of the tyre (in mm).

There's more fun to be had with a pair of 26 x 2.5 though.

aodhu

ok so which is standard for a road bike? what's the difference? I'm just guessing that the thinner wheels are faster, but possibly more prone to puncture?

copacetic

aodhu wrote:

ok so which is standard for a road bike? what's the difference? I'm just guessing that the thinner wheels are faster, but possibly more prone to puncture?

the wheels aren't thinner, just the tires. thinner, higher pressure tires are faster but less comfortable. usually a road
bike will come with 23mm tires, but some higher spec ones intended for racing come with thinner. it varies. have a look online at what bikes come with as td

btw the 650cc wheels aren't older really, they are used in triathlons and for smaller framed bikes to reduce toe overlap.

aodhu

I stand corrected. What's toe overlap?

blorg

Toe overlap is when your foot when fully forward overlaps the front wheel, so that if you move the handlebars left or right the wheel will hit your toe. It's also a problem with mudguards (I have toe overlap with my removable mudguards on my bike.)

GlennaMaddy

blorg wrote:

Toe overlap is when your foot when fully forward overlaps the front wheel, so that if you move the handlebars left or right the wheel will hit your toe. It's also a problem with mudguards (I have toe overlap with my removable mudguards on my bike.)

You just reminded me of how I discovered toe overlap the hard way when I was a kid