Speedo correction - cable type

**Slunnie** · 10th May 2009, 03:12 PM

Sorry if this has been done before. I've done a search and wasn't very successful.

I've got a IIa which I fitted a Stage1 LT95 to. When I fitted 4.1 axles this meant that it was geared correctly to suit 37" tyres instead of 32" tyres. This meant also that the speedo would read correctly with that box, those diffs and those tyres.

I've since replaced the LT95 with a ZF and LT230 from a Rangie, meaning that the speedo will read correctly with all of the ratios when running 33" tyres, not the 37" tyres as the HR is 1.2:1 and not 1.4:1.

In terms of correcting this....
Can anyone point me in the direction of any options on how to correct a cable driven setup?

I thought I'd seen something ages ago on changing little plastic gear sets in the LT230 for the speedo drive.

Will changing HR to a 1.4 gear set achieve the speedo change also or is it purely in the speedo drive mechanism?

TIA for any help...

**PhilipA** · 10th May 2009, 03:25 PM

The speedo drive is taken from th erear main shaft after all gearing except the diffs.
Changing gearbox or transfer ratios has NO effect.

Only changing diff ratios or tyre size has an effect.

However the speedo gear may/will be different in the different transmissions, so you should change the gear to the appropriate one. There was a posting on this last week AFAIR.

Regards Philip A

**Slunnie** · 10th May 2009, 04:45 PM

Originally Posted by PhilipA

The speedo drive is taken from th erear main shaft after all gearing except the diffs.
Changing gearbox or transfer ratios has NO effect.

Only changing diff ratios or tyre size has an effect.

However the speedo gear may/will be different in the different transmissions, so you should change the gear to the appropriate one. There was a posting on this last week AFAIR.

Regards Philip A

Thanks for this Philip!I'm with you, its on the housing between the rear output and the handbrake drum

I've just found this thread which helps
Speedo Drive Worm Gears

JohnR · 10th May 2009, 04:51 PM

You'd be very lucky to fine the exact right gear to fix the error. What you need is a ratio box, If you PM me I can help.

Cheers,

**Bush65** · 11th May 2009, 06:26 PM

Originally Posted by JohnR

You'd be very lucky to fine the exact right gear to fix the error. What you need is a ratio box, If you PM me I can help.

Cheers,

Ive had Marks Adapters make ratio boxes in the ratio needed. Because the thread on the boxes didn't suit the rangie cable they made a short adapter cable that went to the t/case.

**Aaron IIA** · 12th May 2009, 07:13 PM

What ratio spedometer are you using? There will be a four digit number above the right most odometer number. Tell me this number, and I may be able to help.

**Slunnie** · 12th May 2009, 07:44 PM

Originally Posted by Aaron IIA

What ratio spedometer are you using? There will be a four digit number above the right most odometer number. Tell me this number, and I may be able to help.

Aaron, thanks so much for this!

The original series speedo has a the numbers 1408 written in that location. This said, I also have a Defender speedo which I understand was an import and which I'm hoping to replace the original with. The Defender one has the number 3795 on the back on a sticker if it has any relevance to the instrument itself???

**Aaron IIA** · 12th May 2009, 08:10 PM

1408 means 1408 revolutions of the spedometer cable per mile. You need to either slow down your speedometer cable, or get a speedometer that has fewer revolutions per mile. Unfortunately the SWB speedometer had more revolutions per mile. It is possible to change the worm drive in the speedometer, but trying to find a new gear to fit at the correct ratio may prove to be difficult. An engineer who makes gears would be able to do this for you. Alternatively, there appears (from previous discussion in this topic) to be an adaptor that converts the speedometer cable to the correct speed for you. This may be the easiest option, depending on the cost.

Aaron.

**Slunnie** · 12th May 2009, 08:20 PM

Originally Posted by Aaron IIA

1408 means 1408 revolutions of the spedometer cable per mile. You need to either slow down your speedometer cable, or get a speedometer that has fewer revolutions per mile. Unfortunately the SWB speedometer had more revolutions per mile. It is possible to change the worm drive in the speedometer, but trying to find a new gear to fit at the correct ratio may prove to be difficult. An engineer who makes gears would be able to do this for you. Alternatively, there appears (from previous discussion in this topic) to be an adaptor that converts the speedometer cable to the correct speed for you. This may be the easiest option, depending on the cost.

Aaron.

Thats interesting. I wonder what a Defender and a Range Rover one is geared to??? That may also help the calculations.

then again.... or what gear a Defender runs in the transfer.

**LandyAndy** · 12th May 2009, 08:43 PM

Hi Slunnie
My Bro had the same issue in a modded 2A,and was required to fix as a rego issue on inspection.
He ended up buying a VDO electronic speedo that reads impulses off magnets fitted to the driveshaft.You get a measured 1000m press a button and the spedo calibrates itself over the 1000m,press the button and all fixed

Nice looking speedo,direct replacement size for the Landy one too

Andrew

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