Does anyone know if there is a gearbox with a ratio that suits 18" wheels?
Paul, I thought the idea o…
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Can't you just change the…
Can't you just change the gearbox sprocket to give you the speed range you want?
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Michael, sorry if my post…
Michael, sorry if my post was misleading, but I meant speedo gearbox ratio, so as 10mph road speed is 10mph indicated when on 18" wheels.
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Most speedos over read and…
Most speedos over read and a smaller wheel with the same speedo gearbox will do so even more. Best to check against a GPS such as tomtom as these are very accurate. If you decide to fit a cycle type unit, I think they struggle at higher speeds because the speed of the magnet passing the pickup is too high. The soloution may be to fit the magnet closer to the centre of the wheel, then the passing speed will be less. "During the war Rodney" the speedo was supposed to be within 10% accurate at 30 MPH. With modern rolling road MOT machines there is no reason why the tester couldn't give you an idea as to the accuracy of your speedo. Drawing his attention to it may result in a fail though.
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For an MoT, a speedometer…
For an MoT, a speedometer has to be fitted. It doesn't have to work. Strange but true (applies to 1931 on if I remember). And no, I don't know of a speedo gearbox to suit 18" wheels.
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Have a look at www.avontyr…
Have a look at www.avontyres.com/node/129and you can compare the overall diameter of various sizes of tyre. You may find that a fatter 18" tyre will have a similar (or even greater) diameter than the original 19" sizing.
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Re speedo gear box for 18"…
Re speedo gear box for 18" wheels. The rolling radius of a modern tyre may well be very close to that of an old TT100 etc.
Otherwise go to a BSA or Triumph shop and ask for one.
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I see the shit system lost…
I see the shit system lost my post again, what a rerally rubbish web site forumAnd yes i am really annoyed about it all. So why botther even posting a post when the web site simple deletes it all.
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Previously wrote: I see th…
Previously wrote:
I see the shit system lost my post again, what a rerally rubbish web site forumAnd yes i am really annoyed about it all. So why botther even posting a post when the web site simple deletes it all.
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Previously wrote: I see th…
Previously wrote:
I see the s**t system lost my post again, what a rerally rubbish web site forumAnd yes i am really annoyed about it all. So why botther even posting a post when the web site simple deletes it all.
It is a pain, so I always highlight and copy my replies before posting, in case the Guru 503 thing comes up and the message is lost. Then I can refresh the screen and paste the original reply.
It shouldn't happen I suppose, but at least there's a way round it.
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Paul,
I thought the idea of an 18" wheel was that you could use a fatter tyre of more modern dimensions and keep the rolling radius about the same. I haven't done the maths to see if that works.
An alternative is to use one of the speedos now offered by SRM where the gearbox is redundant and you dial in a constant for your wheel just as you would on an electronic push bike speedometer.