[Rob in NH]

My speedometer bounces after 40 mph, is this a cable issue or the speedometer is worn out ?

[JLMounce]

Could be either or both. In my opinion, the cable is the easier job on a '69 (assuming, based on your avatar). I'd start there. If that doesn't cure the issue, the speedometer itself needs servicing. That becomes a good time to freshen up the dash carrier, do a dash harness if needed, replace bulbs etc.

[Cammer-6]

some models have a 2 piece speedo cable assembly
its almost like they didnt have the right ones in the parts bin.
but Im sure engineering dept will say different.
You can disconnect and add some speedo cable lube and try that first.
Also check for sharp bends or contact with exhaust.

[Rob in NH]

Thanks for the replies, I will try oiling it up to see if that helps.

[rdl]

Have you tampered with any components that might be a clue to explain why this has started to happen?

[Rob in NH]

Originally Posted by rdl

Have you tampered with any components that might be a clue to explain why this has started to happen?

I haven't messed with the cable

[rdl]

Check the connection at the gage first to be sure it’s properly clipped in. Then check the condition of the plastic gear in the transmission end (looking for worn or chewed teeth). Also, you can place a drill on that end (gear removed) and test the gage that way.

[necdb3]

If you pull the cable out of the jacket, I usually wire wheel the cable then oil it. Sometimes you'll see a clump of plastic from the jacket on the cable which will cause the bounce.