Speedo Gearing

[Chris KC]

I'll be the first to admit that I've not thought about this very deeply, nor scoured the test books; but my Ulster rep indicates approx half true road speed on the speedo.
It has a four speed gearbox, 19" wheels and 4.9 axle ratio.
 
Wrong speedo I presume?
Or is it possible to swap the drive at gearbox end and correct the reading?
Any thoughts welcomed. I have got used to 'factoring' the road speed but I thought it might be fun to watch the needle hit the end stop some day!

[Ruairidh Dunford]

This may be of use in proving a 'correction' device Chris.

http://pub25.bravenet.com/forum/static/s...5&cmd=show

[Chris KC]

This may be of use in proving a 'correction' device Chris.

http://pub25.bravenet.com/forum/static/s...5&cmd=show

Brilliant, thanks Ruairidh - that seems to cover all the options.

[Chris KC]

In case this topic has piqued anyone's interest, I can now add that both Speedy Cables (London) and Speedograph Richfield (Nottingham) offer a speedometer recalibration service to customer requirements, at £80 and £75 respectively.

Also of possible interest is that Speedograph Richfield offer a range of corrector gearboxes (which also accommodate cable routing changes), typically about £90.
http://www.speedograph-richfield.com/htm...arbox.html

[Mark McKibbin]

Thanks Chris, looks like this is a well researched topic. Think I will go for a corrector box if Speedograph has the right ratio.