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Jan 30, 2008 10:44 am
Jan 30, 2008 10:44 am
Subject: Re: Speedo / rev counter instrument o'haul
Colin,
you said ... "This should produce a graph of percentage error vs 'indicated speed'. Decide the error over the range - say 15%, then contact Speedograph Richfield http://www.speedograph-richfield.com/ and discuss your needs. They are very helpful and have told me they can make up a gearbox of a suitable ratio to fix most problems."
I have had a gearbox made up to fix my (governor) speedo by Speedograph and it works fine, and is accurate as verified by my Road Angel satnav.
The process can be a bit easier - contact them/go to their website and get their form which asks you to measure car wheel revolutions by sticking tape on tyres and rolling it along your driveway then measuring distance, whilst your able assistant notes the number of speedo cable revolutions. Send off that completed form with your speedo and cable and it comes back with a small custom-made gearbox inserted into cable, that recalibrates it, and a relatively small invoice (about £100 for me inc packing and tax).
Only remaining problem with speedo now is that it flickers up to 30mph then stabilises but I have learned to ignore that. No doubt when summer returns and Lagonda outings become more frequent, the flickery speedo will irritate me and I will strip down and clean and lubricate the cables and all will work perfectly.
regards
Colin,
you said ... "This should produce a graph of percentage error vs 'indicated speed'. Decide the error over the range - say 15%, then contact Speedograph Richfield http://www.speedograph-richfield.com/ and discuss your needs. They are very helpful and have told me they can make up a gearbox of a suitable ratio to fix most problems."
I have had a gearbox made up to fix my (governor) speedo by Speedograph and it works fine, and is accurate as verified by my Road Angel satnav.
The process can be a bit easier - contact them/go to their website and get their form which asks you to measure car wheel revolutions by sticking tape on tyres and rolling it along your driveway then measuring distance, whilst your able assistant notes the number of speedo cable revolutions. Send off that completed form with your speedo and cable and it comes back with a small custom-made gearbox inserted into cable, that recalibrates it, and a relatively small invoice (about £100 for me inc packing and tax).
Only remaining problem with speedo now is that it flickers up to 30mph then stabilises but I have learned to ignore that. No doubt when summer returns and Lagonda outings become more frequent, the flickery speedo will irritate me and I will strip down and clean and lubricate the cables and all will work perfectly.
regards