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- This topic has 4 replies, 4 voices, and was last updated 19 years, 1 month ago by katana.
January 23, 2004 at 4:14 pm #8538AnonymousInactive
Can anyone explain what effect changing the size of a bike’s wheels has on the speedo reading? Is there a formula for this?January 30, 2004 at 11:03 pm #17394
The easiest way is to work out the % difference between the 2 wheel sizes and then apply this to the speedo reading (as the % change in dia = % change in circumference, assuming the tyre side wall dimension remains the same).
So, for example, if you were to change from a 16″ to a 17″ wheel that is a 6% (5.88% if you want to be super accurate)increase. Therefore, your speedo would then read 6% slow. So at an indicated 100mph you would be traveling at 106mph.
I’m not sure how you would recalibrate the speedo in practice though?
The best way would be when changing wheel sizes also change the speedo drive or buy one of those electronic bike type speedos that can be reprogrammed.
hope this helps
KatanaJanuary 31, 2004 at 12:14 pm #17395yingtingParticipant
Good explanation. It may be obvious but it’s worth stating that this only applies to the front wheel!
Are pushbike speedos legal in the UK?February 1, 2004 at 7:40 pm #17396
Yes a mate of mine has one off these on his bike and has never had a problem with MOT’s.
KatanaFebruary 4, 2004 at 4:19 pm #17397wheelieParticipant
Thanks guys, always wondered about that myself. Done a lot of wheel changing Katana?February 4, 2004 at 11:04 pm #17398
A fair bit.
I’m currently looking for a reasonably priced front end to transplant onto my bike (Suzuki GSX 750SE Katana) if anyone has got one?
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