Henry Crun Posted January 9, 2002 Share Posted January 9, 2002 My speedo has given up the ghost, so I'm going to have to repair it. However, I know that it reads well over speed, indicating 85mph when doing only 70moh. I understnad this to be related to the cog at the gearbox end of the drive, but how do I found out which is the right cog for me?? Link to comment Share on other sites More sharing options...
sjwb Posted January 9, 2002 Share Posted January 9, 2002 Tinbum, Ditch it and fit a cycle computer. Cheaper, more accuracy and functionality. See you on the 15th. Steve B Link to comment Share on other sites More sharing options...
Klaus Loske Posted January 10, 2002 Share Posted January 10, 2002 If your speedo is really dead, why not go for the VDO electronic speedo which has the same diameter then the old one. You can connect the electronic speed sensor to the speedo cable. The nice thing is that you can calibrate the speedo yourself. There are some threads on the list so search for speedo to get more. Klaus Link to comment Share on other sites More sharing options...
Nigel Riches Posted January 12, 2002 Share Posted January 12, 2002 Tinbum, not going rusty are you, well anyway about your speedo question, the two previous replies are possibly the easiest means of regaining an accurate speed indication, as the speedo drive gear is usually a right bastard to remove, if not impossible without removing the gearbox from the car, the gear you require is determined from the axle ratio:- Axle ratio Speedo drive gear Colour 3.54:1 22 teeth White 3.62:1 24 Black 3.64:1 22 White 3.77:1 23 Black 3.89:1 24 Green 3.92:1 24 Black 4.11:1 25 Blue The above is good if you have a speedo calibrated at 1000 turns to the mile, and are using a Ford gearbox, if you have a de Dion axle your speedo would be calibrated at 1100 turns to the mile and the axle ratio would be 3.62:1, hope this is some help, Nigel. Link to comment Share on other sites More sharing options...
Allan Haighton Posted January 12, 2002 Share Posted January 12, 2002 Just to add to the complication - the Ford Escort 4 speed box can have two different drive gears (6 teeth or 7). 7 is normally fitted, but not always - it wasn't in my box. So even if you choose the 'right' speedo drive gear, you still may not get the right calibration. What fun. Link to comment Share on other sites More sharing options...
NickD Posted January 20, 2002 Share Posted January 20, 2002 Also note that tyre size is a minor factor in speedo gearing as diameters vary by about 15% between the largest (205/45-16) and smallest (20" slick) sizes used on 7s. If you let me know your tyre size/final drive/speedo type, I can advise the appropriate gear. Link to comment Share on other sites More sharing options...
Andy Checkley Posted January 21, 2002 Share Posted January 21, 2002 I wasn't sure about my speedo accuracy so I tried the bike computer route, and because you can calibrate it so accurately by setting in the wheel rolling circumference, you can get it pretty close. It turned out my speedo seemed to be pretty accurate, until you got up above 85mph. After that it seemed to under read by a touch. (tested on a few trackdays, officer!) Link to comment Share on other sites More sharing options...
Tight fart Posted January 22, 2002 Share Posted January 22, 2002 theirs a firm in islington called speedy cables that repair and calibrate speedos if you can't find them email me T.F@O.F Link to comment Share on other sites More sharing options...
Blatman Posted January 22, 2002 Share Posted January 22, 2002 Speedy Cables have movedblush.gif Cables and control systems are in Wales somewhere. Instruments are in Herts somewhere. I posted something to this effect a while back. If I can find it in the archives, I'll re-post the info. Found it.......... Speedy Cables have moved. Head office, and cable division, is now at unit 14, Merchant Drive Hertford SG13 7AZ 01992 581600 Instrument Division Abercrave Swansea SA9 1SQ 01639 732213 Edited by - Blatman on 22 Jan 2002 10:05:37 Link to comment Share on other sites More sharing options...
KayTee Posted January 22, 2002 Share Posted January 22, 2002 Where do I get all these coloured drive gears ? Before you state the obvious: German Ford's don't even have the water-pumps any more ... THANKS ! - Karsten Link to comment Share on other sites More sharing options...
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