trailtech vapour speedo for yz450f,correct wheel circumferernce

hi guys,want to check that my vapour speedo has the correct wheel circumference setting for my yz450f supermoto,could you please tell me if i'm correct.......... i have a 17 inch front wheel....converted to mm is 432mm and according to trailtech you then times that by 3.14 giving a circumference of 1356mm that you programme into the speedo to give correct speed,does this sound correct please guys?

Do you need circumference of the wheel or the tire for that speedo?

I would think you would want the Tire.

If so just measure across the tire and get your diameter then multiply times 3.14 for circumference.

Later, Jason

This question makes perfect sense after reading your other thread. If you are using the wheel and not the tire that is going to give you a slower speed on your speedo. Hope this is all it is.

Put a small blob of grease or paint on the tire and roll the bike across the garage floor. Measure between the marks on the floor and that is the spec you need for your Trail Tech.

This question makes perfect sense after reading your other thread. If you are using the wheel and not the tire that is going to give you a slower speed on your speedo. Hope this is all it is.

ok,previous owner had circumerence set at 1550 where the actual tyre with top to bottom is 585mm giving a circumference of 1836mm....bigger,not sure how big a difference to the speedo this will be but sure it will be different,just hope ive not been caught by any speed cameras whilst riding with a slow speedo

Edited by adamshackleton
wrote wrong

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