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Posted: Sat May 10, 2008 5:15 pm
by Arthur
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.

Posted: Sat May 10, 2008 6:54 pm
by willhub
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.

Posted: Sat May 10, 2008 8:34 pm
by Arthur
You need 2096 then. The good news is that you'll go instantly faster ;)

Posted: Sun May 11, 2008 4:17 pm
by Arthur
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.

Posted: Sun May 11, 2008 5:41 pm
by willhub
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?

Posted: Sun May 11, 2008 8:23 pm
by Arthur
2096 is only about 2% smaller than 2145 so it's not a vast difference: .4 mph at 0 mph.

Posted: Mon May 12, 2008 1:18 pm
by Dr Dave
Do it the proper way - measure a full revolution (weighted!) in mm ;)

Posted: Mon May 12, 2008 1:38 pm
by willhub
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.

Posted: Mon May 12, 2008 3:01 pm
by Arthur
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.

Posted: Mon May 12, 2008 3:20 pm
by willhub
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 :P