speedo not working

[jamcarr2]

Hi I am a relatively new member, June this year same month I got the stag . The problem I have is the Speedo is not working properly it reads about 10 miles slower than it is actually doing (travelling at 70 Speedo says 60) and as I have six points already for speeding it is a bit worrying to say the least. Can any one tell me where I can either get a new one or get my one repaired .I did get one of e- bay described as good working condition but it was worst than mine thanks john

[seaside bill]

imported post

It's probably your tyre size. Speedos were calibrated for the original factory spec tyres (185/80 - 14) which are now difficult to get. Depending on what tyre size isfitted to yours there will be a degree of error on your speedo - go here to calcuate it http://www.miata.net/garage/tirecalc.html

A non-standard differential will also give you the same problem. You don't need to get a new speedo, just get yours re-calibrated. A specialist like http://www.jdo1.worldonline.co.uk/ can re-calibrate it for you.

[jamcarr2]

imported post


Thanks for that bill my tyres are 185-80-14 and the diff is original but I think the problem is the Speedo because at a steady 30 miles a hour the needle wavers between 25 and 30 then the faster I go the steadier it becomes but the more inaccurate it becomes . I will try the company that you suggested and see if they can help

John

[seaside bill]

imported post

John

OK, if you're looking at a repair another specialist is http://www.speedycables.com/I've never used them but I've heard others recommend them

[John Wright]

imported post

You may have a different differential ratio from the one for which the speedo was intended (replacement diff or speedo).

John

[Stagdad]

imported post

John

Sounds like you've got a kinked cable,if it's bouncing around.

Steve

[stustag]

imported post

Hi John

Yes it could be a poorly routed cable had this before or the cable is frayed internal and catching on the cable casing.

The other possibilty is the drive gear might be worn this fairly easy to remove and check see 37.27.01 in the ROM.

Stuart

[Andrew]

imported post

My speedo is also 10% out due to larger tyres. I measured the actual with a hand held GPS.