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Discussion Starter #1
Morning!

I've tried searching and am coming up empty handed so far so I figured I'd reach out and ask.

Does anyone know the "speedometer ratio" on our TW200s? I'd like to replace the factory speedometer with a smaller aftermarket unit and noticed that most of them use the 60MPH @ 2240RPM ratio, it seems to be a common ratio among motorcycle manufacturers. Will this produce an accurate speed reading on the TW200? If not, any tips on what I should look out for?

Thanks in advance -Mikey
 

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I can't confirm what the TW is, but as you found the 2240RPM=60 is pretty common among Japanese bikes. I'd doubt the TW is an exception. The stock speedo isn't particularly accurate anyway, with the stock front tire it has the typical "optimism" of about 8%. So 60 indicated is more like 55 actual.

If you want something smaller, you can get loads of small digital speedometers that just use a magnet and wheel sensor, which can be calibrated to any wheel/tire size since it just counts RPM and then multiplies by wheel circumference you program in to get speed. Trail Tech is a popular brand and has a few different options, but if you want something small/discrete a bicycle speedometer works just as well.
 

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This is an excellent question, and I do not have the answer. However, as I recall, I think you can put a screwdriver into the hole from the speedo drive and turn the wheel ten times and count the revolutions and multiply.
 

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Discussion Starter #5 (Edited)
Great info guys! Thank you for your insight. There was a toy looking magnet zip tied to my front wheel when I bought the bike, which leads to me believe it had a digital speedo at some point. It also suggests that my bike has more miles than I originally thought :smileinbox:

I think I'll try one of the small motorcycle speedo's with the 2240:60 ratio and just see what happens. I believe I'm running a slightly larger than stock front tire anyways so maybe it will end up being a bit more accurate speed reading?

Current front tire is a Shinko 244 size 5.10-18 which based off my probably incorrect calculations is a 2.3% circumference increase over stock. Or am I thinking backwards? This is all pretty new to me.
 
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