Wheel size - VDO computer

Peter_49 <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Hi,

I have two bikes one a road bike with a 700x23c wheel and a MTB with a
26x2.1 wheel. I was surprized to see in the manual of "VDO Cytec C08
computer" the same wheel size 2133 mm (84.0"😉.

The wheel size indicated for the MTB in the manual is actualy 26x2.125
(mine is 2.1).

I have couple of questions:

What is the meening of the numbers 700x23c and 26x2.1?
How come two different wheel sizes has the same 2133mm circumference?
Or is it a mistake in the manual?

Is there any other way to calculate the wheel side, not using the ruler
taking into account the data the manufacturer of the tire gives?

Thank you

Peter

I just wish there was a simple way to verify the calibration of one of
these things. Kinda hard to use mile markers like you would in a car.
I guess you could visit a school and time yourself going around the
track at an even pace.

Peter_49 said:

Hi,

I have two bikes one a road bike with a 700x23c wheel and a MTB with a 26x2.1 wheel. I was surprized to see in the manual of "VDO Cytec C08 computer" the same wheel size 2133 mm (84.0"😉.

The wheel size indicated for the MTB in the manual is actualy 26x2.125 (mine is 2.1).

I have couple of questions:

What is the meening of the numbers 700x23c and 26x2.1?
How come two different wheel sizes has the same 2133mm circumference? Or is it a mistake in the manual?

Is there any other way to calculate the wheel side, not using the ruler taking into account the data the manufacturer of the tire gives?

Thank you

Peter

for the numbers check out
http://www.schwalbe.com/index.pl?modus=lang&punkt=261&abstract=1144&bereich=&einsatzbereich=&produktgruppe=
it is no mistake, if you measure the diameter of both your tires you will see it's about the same. if you want the exact measurement you will have to do it like on page 10 of your manual. there is no other way.

Dave said:

Peter_49 <[email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

Hi,

I have two bikes one a road bike with a 700x23c wheel and a MTB with a
26x2.1 wheel. I was surprized to see in the manual of "VDO Cytec C08
computer" the same wheel size 2133 mm (84.0"😉.

The wheel size indicated for the MTB in the manual is actualy 26x2.125
(mine is 2.1).

I have couple of questions:

What is the meening of the numbers 700x23c and 26x2.1?
How come two different wheel sizes has the same 2133mm circumference?
Or is it a mistake in the manual?

Is there any other way to calculate the wheel side, not using the ruler
taking into account the data the manufacturer of the tire gives?

Thank you

Peter

I just wish there was a simple way to verify the calibration of one of
these things. Kinda hard to use mile markers like you would in a car.
I guess you could visit a school and time yourself going around the
track at an even pace.

There is a simple way. Measure the actual rollout of the wheel, using a
tape measure. For better accuracy, measure ten rotations with your
usual riding weight on the bike.

Now you have the circumference. The computer counts the rotations to
give distance, and has a clock to calculate speed.