Speedo reading about +10 mph

[Smosh]

I replaced the Speedo able at the weekend and its now reading about 10mph too fast at 20mph. Since it stopped working, I have put new wheels and tyres on in it. I didn't think it would have that great an impact!?
Did I miss something installing it? I haven't a clamp on it like shown in the haynes because my old one was broke an just hanging around- so I cable tie it out the way...

[kevtherev]

What are the tyre sizes and the new wheels sizes?

[Smosh]

190/70r15 so 15" wheels.

[Aidan]

ok your tyres are very slightly smaller than stock I think so the speedo will overread by more than normal, the speedo is designed to overread by about 10% so at true 50 it says 55, but 10mph over above 30 says the needle on the speedo was fitted incorrectly, does it sit against the stop at 0mph ?
Oh and have you got a lhd with a kph speedo with a mph sticker fitted ontop of the original speedo ?

[kevtherev]

195/70 would have been a bit better.

[Smosh]

Aiden, Yea, the speedo drops to the top at stationary. It wasnt an issue before it stopped working, that said it used to bounce alot! RHD, and no sticker as far as i know!

Kev, balls! my tyres are 195/70. Typo! I want to say that i had 185/80 previously. I still have them so I will double check.

[CovKid]

Sounds like speedo prob. I run on 195 80s (balloon tyres) and my speedo is spot on compared to stock tyres

[ghost123uk]

I replaced the Speedo able at the weekend and its now reading about 10mph too fast at 20mph. .

Agree with CovKid = it's a speedo problem, but a fairly easy, though very delicate fix.

Remove speedo.
Very very carefully edge the "needle" over the top of it's "resting pin"
Very Very carefully remove the needle.
Replace it at about a 10mph increment further anti-clock wise from where it was resting when "off the pin".



Very very carefully lift it back over the resting pin.
Temporarliy re-connect the speedo (no need to fully assemble yet).
Take it for a test drive and check with your sat nav.
Make further adjustments as required.
Re-assemble to whole lot

Do be VERY careful of the tiny coiled hair spring in the centre, behind the actual needle. It is VERY delicate and if you damage it, you are stuffed (ask me how I know )



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By the way, here is a pic of the cog that slips on it's shaft, causing the odometer to stop working.



I recommend you DO NOT try and glue it, remove it, roughen up the shaft by gently squeezing it in the serrated jaws of a pair of pliers, note, it takes remarkably little pressure to get just the "right" amount of roughing up of the shaft = don't over do it or you will split the cog on pushing it back. The whole operation is a bit tricky, but do-able with care and ingenuity (I have more pics of how I did mine if anyone need them)

[Smosh]

Is this how i wind back the mileage also!

ok thanks, will have a look. What would have cause it to slip out of position? Dumb question #12897 would it have made a difference that I prob put the cable into the speedo prior to putting it into the hub?

[ghost123uk]

Is this how i wind back the mileage also!

I wouldn't know

What would have cause it to slip out of position?

It won't have "slipped" out of position. I don't know why it's wrong, perhaps a previous owner has messed with it (clocking it ??) and re-assembled it wrongly?

Dumb question #12897 would it have made a difference that I prob put the cable into the speedo prior to putting it into the hub?

No, doing that cannot have caused this.

At least the fix is, as mentioned, doable but take care, it's pretty delicate in there.

[Smosh]

Sp tried fixing this today, snapped the "bar-steward" needle!

Glued it back together, shorter so it doesnt hit the stop. still reads +10!?

Any other clues?

[CovKid]

source another speedo

[ghost123uk]

Put the needle on in a further anticlockwise position.

[BMEC]

I have a 1985 1.9 DG which I have owned from new. The speedo has always read about +10mph. It is still using the original speedo cable and has always been fitted with the standard commercial tyres 185 14C on the original steel wheels. I have had it too long to fiddle with it now!

[Smosh]

If you've owned it from New, didn't you think to address it under warranty early on? Owning it from New and and still owning it is pretty cool, can't think that there are many people left that have?

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