NC35 speedo reading

[arsey30]

Does the nc35 speedo read the same as the nc30 i.e 1000rpm per 10mph.
Looking at gearing and wheel size, 40/38 t, 18/17" wheels it seems as it should [geared up 2/40th, and down 1/18th]

My nc 35 was reading slow after somone fitted an mph dial and refitted the hand in the wrong place. [7000rpm showed 62mph]
I have reset mine and it now reads 68mph at 7000rpm.

Thanks,

Dave.

[viper_biker]

It's not normally a rule of thumb as there are many variables to consider, uphill, downhill, weight of the rider, direction of wind etc etc. Only way to get a more accurate reading is via GPS or have someone with a calibrated speedo to sit beside you and do 30mph, 50mph and 70mph so that way you'll at least have the basics covered.

[arsey30]

Thanks, I will check against a few other vehicles.

I don't see how speed can vary against a given top gear rev though, unless clutch is slipping.
If 7000rpm shows 70mph, it always will, up or down hill.

Am I missing something?

Dave.

[viper_biker]

As far as I knew it, your bike will rev a bit higher to get the same performance if obstructed by things like a steep hill, I don't mean that if 7,000rpm is normally 70mph but drops to 50mph if on a hill but will loose some speed, for talks sake lets say 68.5mph. I may well be wrong, but that's how I understood it to be.

[arsey30]

Only if the clutch slips
Under load, like hill or headwind will mean opening the throttle more to achieve the same speed, but surely revs are linked to speed and won't alter, how can they if speedo is driven from gearbox, rev counter from engine, when one alters, so does the other, by the same amount. [assuming same gear, in this case top]

My nc30 always shows 1000rpm for every 10mph
I think I can see your thinking, loading the engine requires more power for the same speed.

Dave.

[Neosophist]

Since the speedo's a mecanical device / spring you might want to calibrate a set speed to be accurate, i.e. 30/40/50mph. Simply ride with a gps at the given speed and note what your speedo is actually reading and you'll know how far to move the needle, repeat until accurate.

Notable items include that even if the speedo is accurate at 30/40/50 it might be less accurate at higher speeds due to the way it works, even temperatue might affect its accuracy.

Most speedos' over-read a little, 10% is a acceptable tolearnce. This is always going to be better than your speedo under-reading as your less likely to be fined. :)

[arsey30]

I accept speedos over read by a percentage [6-8%?] so will become more inaccurate as speed rises [so does the rev counter, that is no more accurate, as it keeps pace with the speedo reading] i.e 1000rpm per 10mph

Mine appears 2mph slow at all speeds, I am just after a base setting, which is why I asked what readings others get on a 1000rpm against mph.

Dave.

[rossrs]

Mine always used to show 10mph/1000rpm in 6th. It only stuck in my mind because I was amazed it could pull in top from 30mph @ 3000rpm. Just bought it back and I'm sure nothing has changed

[arsey30]

Thanks.
Dave.