Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Speedo Readings

[Steve M]

Originally posted by weeveetwin
I guess this also means that when your clock says your bike's covered 10,000mls, its really only covered about 9,000!

Good point this, as more miles = lower value and sooner servicing (if you do it by miles rather than anually) Though the milometer and speedometer are not necessarily both reading wrong or by the same amount.

[webbyc]

I'm baffled by this - the only thing I've done from standard is to raise the rear sprocket to 38 instead of 36. Would that make any difference?

Or is just that rice burner clocks way overread to make their riders feel better?

[Edited on 24-6-2004 by webbyc]

[MJS]

Originally posted by STEVE M

Good point this, as more miles = lower value and sooner servicing (if you do it by miles rather than anually) Though the milometer and speedometer are not necessarily both reading wrong or by the same amount.

I've done the same journed from Northampton to Camberley, around 90 miles, and clocked a good mile and half difference between my 996 and zx6r - can't remember which one clocked which, but I was surprised by the difference at the time.

[Edited on 24-6-2004 by Urban996]

[mike916]

Cant make a differance the speedo dries on the front whek init

Originally posted by webbyc
I'm baffled by this - the only thing I've done from standard is to raise the rear sprocket to 38 instead of 36. Would that make any difference?

Or is just that rice burner clocks way overread to make their riders feel better?

[Edited on 24-6-2004 by webbyc]

[Ray]

On a 748/916/99* the speedo is driven by the front wheel so gearing changes don't affect the speedo. Most if not all monsters and most other Ducs do as well. Don't know where these new fangles Multistranglers or 999 types take the speedo feed from.
Using the front wheel pickup there will be slight differences between tyre makes and as the tyre wears due to differences in the circumference/rolling diameter.

Jap bikes tend to use a speedo drive from the gearbox so gearing changes do affect speed readings.

As for the over reading causing more services, quicker drop invalue etc isn' that why some helpful individuals offer "mileage correction"

Ray

[Garibaldi]

Bike magazine reports speedo accuracy in its tests. July's test of nthe 749S, 999, RSV-R and Benelli Tornado Tre were as follows:

749S 70mph ind = 66 real , 100mph ind = 95 real
999 70mph ind = 65 real, 100 mph ind = 92 real
RSV-R 70mph ind = 66 real, 100mph ind = 93 real
Benelli 70mph ind = 63 real, 100mph ind = 90 real

So indicated is typically 5-7% lower than real on the dukes and up to 10% lower on the Benelli.

Don't have any Jap bikes to compare against but I'll keep 'em peeled next month.

[Steve M]

I've done the same journed from Northampton to Camberley, around 90 miles, and clocked a good mile and half difference between my 996 and zx6r - can't remember which one clocked which, but I was surprised by the difference at the time.

[Edited on 24-6-2004 by Urban996]

same journey to north Wales done many times - my wife's VW Polo read 75 miles, my bike always reads 71 miles.
Wonder what her new car would say.

[Shazaam!]

The 998 and 748 hub speedometer gears are the same. The speedometer error for a 998 with a 70-section was measured against a GPS standard by one owner to be:

40 998 = 37 GPS
50 998 = 46 GPS
60 998 = 56 GPS
70 998 = 65 GPS
80 998 = 73 GPS
90 998 = 82 GPS
100 998 = 89 GPS

If you switch to a 60-section tire (that comes standard on a 748,) the circumference is smaller than a 70, so the wheel sees more revolutions per mile and the speedometer reads higher. Consequently, the speedometer reads closer to the true speed (still low,) and it’s more accurate on a bike with a 60-section tire.

[BDG]

I ran a tuned Blackbird at Bruntingthorpe and the speedo would show 205 to 210mph but through the timing lights the best was a genuine 186mph.

Same story with Kwak ZX9R, ZZR1100 and even a Honda VFR800 indicated nearly 170mph! which was a true 156mph.

All the speedo's that day were roughly 10% over.

Just to compound matters i had an ST4 that rarely showed more than 130 when other people would be showing upto 160mph. Speedo's on ST4S and 996SPS always seem to read less than friends bikes so maybe Ducati speedo tell fewer lies.

[rockhopper]

If anyone is in the Midlands and wants to borrow my GPS so they can check their speedo they are more than welcome.