slow speedo

[vicfox47]

Dear all,
The speedo on my 71 Traveller under reads by 5-6 mph at 30mph, I have checked it with my satnav and it is consistently at least 5mph behind even at higher speeds, could it be the cable or the speedo itself? I would welcome any advice.
Regards,
Vic.

[MarkyB]

You could check what diff is fitted and if it suits the TPM of your speedo.
They were never accurate even when new and always under read to some extent.

[bmcecosse]

It certainly can't be the cable. Is the mileometer reasonably accurate - try checking that against the sat nav for a known distance. The needle may simply need repositioning on the spindle - if the mileometer is accurate. Otherwise - could well be as above - wrong TPM for the final drive ratio fitted. Assume you have standard wheels/tyres fitted ??

[vicfox47]

Dear both,
Thanks for the reply, I have checked it with a satnav and a tacho and they confirm a very slow speedo, it is on a std axle and wheels and tyres so I guess a new speedo is the answer.
Regards,
Vic.

[Trickydicky]

Here is a manual to strip and repair speedometers, http://obswww.unige.ch/~wildif/cars/doc ... repair.pdf
Hope it helps.

[bmcecosse]

You say 'standard' axle - what ratio? What year car -what engine capacity. And what TPM is the speedo? Is the mileometer slow by the same % as the speed indication? No point getting a nother speedo till you know what TPM you need !