Smiths speedometer telemax- recalibration

[snowy892]

Afternoon all, 

I need to recalibrate my smiths speedometer, I've got a pre 2004 telemax type. 

I've measured that it does 69 inches  per full wheel rotation. You then somehow need to turn that figure into a number on the speedo, which i can access!

Instructions on caerbont automotive website are somewhat confusing (to me) 

Can anyone simplify the process for me. 

[GaryD1971]

Hi Richard.

Does the below help at all? 

 

Very similar process to my raceline speedo. 

 

Gary.

 

 

[snowy892]

Hi Gary,

Thanks for the info, unfortunately that for 2004 onwards mines a pre 2004 unit. 

https://www.smiths-instruments.co.uk/app/uploads/2023/05/pil017-368.pdf

 

https://www.smiths-instruments.co.uk/app/uploads/2023/05/speedo-dip-switch-tables-437.pdf

 

If you ever get time, read the above!!

[p k]

Need a little bit more information.

Where is the sensor mounted .

How many pulses (bolt heads passing the sensor per wheel rotation)

Possibly diff ratio

 

 

[snowy892]

Hi PK

Sensor is mounted on the drivers side wheel

bolt heads passing the sensor per wheel, i don't know - is it a case of just watching it? 

Dif I believe is standard 3.62

[p k]

14 minutes ago, snowy892 said:

Hi PK

Sensor is mounted on the drivers side wheel

bolt heads passing the sensor per wheel, i don't know - is it a case of just watching it?  

Dif I believe is standard 3.62

Yes . it should be fairly obvious what passes near the sensor just need how many in one wheel rotation  

[GaryD1971]

If it's pointing at the disc, it'll be four bolts per revolution. 

By my reckoning, your tyre turns 918.2 times per mile.

918.2 x 4 = 3672.8 or 3673.

The table shows the switch settings for 3672 which will be close enough. 

 

 

Set the switches to the settings above for 3672 and follow the rest of the instructions. 

That should do it. 

[GaryD1971]

Assuming the drivers side wheel you refer to is the front wheel?

[snowy892]

Hi Gary, 

Andy from Siltech replaced his version of the speed sensor from the 4 bolts to a disc with multiple teeth on it. It looks like I'll take take wheel off to count the teeth. 

 

[GaryD1971]

11 minutes ago, snowy892 said:

Hi Gary, 

Andy from Siltech replaced his version of the speed sensor from the 4 bolts to a disc with multiple teeth on it. It looks like I'll take take wheel off to count the teeth. 

 

 

Yep, definitely. Then multiply 918.2 by the number of teeth/pick up points. 

[snowy892]

There's 20 of them. 

918.2 x 20 = 18364

[snowy892]

Hopefully, getting somewhere 

[GaryD1971]

I would say so. That should give a small amount of over read as well, which is good.  

[GaryD1971]

Don't know about you Richard, but it's peeing down this side of the county,  so a road test may be a bit damp...

[snowy892]

Road test, not a chance. It's like a river!!