Race Technology

I've been setting up the speed display of the D2P on a motorcycle. I originally used a rear tyre rolling circumference figure I obtained from the 'Net (just lazy) and that produced the exact same speed/rpm data as others have published and indeed also the same as a dedicated gearing calculator site. So my calculations would appear to be correct. But the bike's speed displays too low.

Most vehicles display approx. 5% fast, but mine was about 5% slow, so I was in fact travelling faster than what was displayed. This was comparing it to a GPS I could see at the same time, with its speed displayed. I have now adjusted the D2P appropriately and need to test against the GPS, but it should now be correct. However, that means everyone else's speed/rpm data is not correct and this seems to indicate that the rolling circumference of the rear wheel (190/55x17) is actually larger than what everyone else is using to create their gearing charts etc.

Or my D2P is calculating it incorrectly. This would seem unlikely since its main function is to be accurate at stuff like this. But at the moment I cannot determine the source of this discrepancy.

Anyone got any ideas?

I may have the answer. I'm using an RT pulse divider to reduce the pulse rate from the ABS system to a lower frequency that the D2P can actually handle. I ordered this with 15:1 reduction and configured the D2P accordingly. Later I was informed the latest dividers only divide by even numbers so mine is actually 16:1, but in my rush to get it finished in time, I didn't notice this.

I have now modified the config to suit a 16:1 reduction and will see how that goes. I suspect it will be ok now.

Can someone help with continuous blink dots?