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Speedometer accuracy USA v Europe

Posted: Fri Oct 05, 2018 2:32 pm
by cnikonpete
I have often been surprised by the top speed of the US market PCX 150 being quoted as 60mph.

Does the US have more stringent laws regarding speedo accuracy? It appears in Europe speedo inaccuracy is “tolerated” as long as the speed shown is over the real speed,but not more than 10%.

My 2018 125 is over by approximately 7.5% in comparison to a gps signal,so when I squeezed 70mph out of it, the true speed was about 65mph.

I know US gallons are different from the UK,but surely not miles? I think my odometer is accurate however, otherwise the impressive mpg goes out of the window as well.

So I think in future,to avoid top speed envy, we should all quote from inaccurate speedometers when needing reassurance,and gps when pulled over by the law.

Re: Speedometer accuracy USA v Europe

Posted: Fri Oct 05, 2018 3:22 pm
by you you
I think this has been done a few times before.

General opinion was that USA speedos were more accurate than Europe. If it's true I'm not sure why.

60/65/70, does it matter? Some ways away from causing a sonic boom and you are always going the speed you are going.

Re: Speedometer accuracy USA v Europe

Posted: Fri Oct 05, 2018 4:44 pm
by Mel46
My speedometer is off in the lower speeds but creeps up till at 45mph it is right on and stays that way from then on.

When i say that it does 75 mph as its top end with the NCY variator setup, i don't mean that it shoots up to that speed, though. We have a lot of hills here in Georgia so my tests are on level ground. It will hold 75 as long as the road stays level.

It's biggest advantage is being able to maintain 55 mph as the road starts to incline.

Re: Speedometer accuracy USA v Europe

Posted: Sat Oct 06, 2018 6:05 am
by cnikonpete
Maybe the laws regarding speedometers are different in the US from Europe and the manufacturers adapt to suit.

I can't tell the difference between 60 mph and 65 mph for instance,so it makes little or no difference to my enjoyment of the bike,just interested why,in the age of digital speedometers, the discrepancy is there.

Only tried GPS as I had downloaded app on my hand me down (from the wife) i phone.

I read that manufacturers were afraid of lawsuits if someone could prove that they were fined for speeding due to inaccurate speedometers showing less than true speed,but who knows?

Re: Speedometer accuracy USA v Europe

Posted: Sat Oct 06, 2018 9:23 am
by Mel46
If anything the speedometer would show higher speeds than the GPS. I expect that they set them that way because of the possibility of legal actions.