'My Cycling Log'

Arthur · Post by **Arthur** » Sat May 10, 2008 5:15 pm

willhub wrote: When I set up my speedo I put in 2145, someone in my street did some maths or something to make sure it was the right value, so if I said 11.7 miles is that ok?

What size are your wheels are tyres? The link I posted above has a table of values to put in for various wheel/tyre sizes, which should be good enough.

willhub · Post by **willhub** » Sat May 10, 2008 6:54 pm

Arthur wrote:
willhub wrote: When I set up my speedo I put in 2145, someone in my street did some maths or something to make sure it was the right value, so if I said 11.7 miles is that ok?
What size are your wheels are tyres? The link I posted above has a table of values to put in for various wheel/tyre sizes, which should be good enough.

My tyres are 700x23.

Arthur · Post by **Arthur** » Sat May 10, 2008 8:34 pm

You need 2096 then. The good news is that you'll go instantly faster

Arthur · Post by **Arthur** » Sun May 11, 2008 4:17 pm

Arthur wrote:You need 2096 then. The good news is that you'll go instantly faster

Sigh. Slower. I mean the speedo will read slower.

willhub · Post by **willhub** » Sun May 11, 2008 5:41 pm

Arthur wrote:
Arthur wrote:You need 2096 then. The good news is that you'll go instantly faster
Sigh. Slower. I mean the speedo will read slower.

So I am going like 1+mph slower than it says?

Arthur · Post by **Arthur** » Sun May 11, 2008 8:23 pm

2096 is only about 2% smaller than 2145 so it's not a vast difference: .4 mph at 0 mph.

Dr Dave · Post by **Dr Dave** » Mon May 12, 2008 1:18 pm

Do it the proper way - measure a full revolution (weighted!) in mm

willhub · Post by **willhub** » Mon May 12, 2008 1:38 pm

Dr Dave wrote:Do it the proper way - measure a full revolution (weighted!) in mm

How? Drawing a line on the pavement, then moving a full rev and put another line and measure it? I am sure that came out with 2145.

Arthur · Post by **Arthur** » Mon May 12, 2008 3:01 pm

See link I gave above. You need to measure the revolution with your weight on the bike if you want to be accurate, otherwise you'll get a number that's too big.

Or just use the 2096 from the tables, which is all I ever do.

willhub · Post by **willhub** » Mon May 12, 2008 3:20 pm

I dont think I will bother if the difference is minimal tbh cause as some other people say its not the milage on the speedo that counts its what is in your legs