Wheels, sizes and speed differences...

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Mikekitts81
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Wheels, sizes and speed differences...

Post by Mikekitts81 »

I just got myself a pair of mz baghira enduro wheels of a guy called David from up Barnsley way now I've been looking to have these for years but could never find any as anyone who as um just don't tend to sell them .....at the minute the baghira is running on 2 17inch supermoto wheels now these enduro wheels are a straight fit same discs hubs everything straight swap back an forth ... the enduro wheels are 18 back 21 front ... so we're iam unknowledgeable and technically unaware is how much is my speeds gonna change on my speedo as it's a different set up and size ... or will it not be noticeable at all ... iam thinking of just going really slow throu any speed cameras etc at minute to make sure iam not to fast but it would be nice to know if there would be a drastic change in the speed rolling on these wheels ..... Image

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Spout
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Re: Wheels, sizes and speed differences...

Post by Spout »

If the speedo drive is off the front, then will change by 21 seventeenths.
And if off rear, by 18 seventeenths.
That's it simply, but tyre aspect will alter the ratio. Best to measure the circumference of each set up for a better ratio.
If you're bothered, work out with a calculator various speeds and speedo errors. There's nothing worse than trying to do these calcs in your head in heavy rush hour!
Curzon
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Re: Wheels, sizes and speed differences...

Post by Curzon »

Youv've got two options really. Either change the speedo drive gear when you swap the wheels over. Grahams Motorcyles list different part No's for the speedo drive gear for the 17" & 21" front wheels. Alternatively, use a handle bar mounted GPS device to measure speed when youre using thr 21" wheels, either a GPS cycle computer or sat nav.
P4ulie
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Re: Wheels, sizes and speed differences...

Post by P4ulie »

With the supermoto wheels my speedo is out by up to 12mph, it seems to vary from 0 at about 20, 30 - 40 is around 5 mph & as you take it up, 9 is about the average.
If I'm on a trip I keep an eye on the GPS, but as long as you are aware your speedo is inaccurate you should be fine. I actually find I overcompensate & quite often below the posted limits around cameras. I've yet to get flashed.
If you hoon it around everywhere, accurate speedo or not, you're probably going to lose your licence, or have a nasty incident at some point in the not too distant future.
With enough profanity, you can accomplish anything
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