Does anyone know what ratio the gearing on the speedo drive is?
Edit: On a TracK/Kick

You know, I've looked into this before and never really gotten a good answer.  The $8 it took to fix my Ranger's speedo was a hell of a lot better (and less troublesome) than the $140 I've got into the GV's speedo so far...




This is just my way of bumping this question back up to the top and subscribing to the thread. .

Thinking about it some more I remembered that I have a spare tcase somewhere. If it has a speedo drive on it then I will check the ratio.

Hi Rhino ,

What you up to this time?

The Kick and Sammy speedo's both have the same markings - 637rpm / 1 km if that helps - eg: they are interchanegeable gearing wise 

Hope this helps

ZeusZuki

Hi Rhino ,

What you up to this time?

The Kick and Sammy speedo's both have the same markings - 637rpm / 1 km if that helps - eg: they are interchanegeable gearing wise  

Hope this helps

ZeusZuki

Trying to do the software for the Vehicle Speed Sensor for the EFI. I know I get 4 pulses every time the cable goes round, I just need to turn that into actual speed.
I assume thats 637 turns per Km 

Here's where you can find out all about Speedo Gear:

http://www.speedousa.com/

Just don't come on here and model it for us, OK?   

Here's where you can find out all about Speedo Gear:

http://www.speedousa.com/

Just don't come on here and model it for us, OK?   

Lol, one of your bookmarks is that?

Rhino,

That is the way I interpret it to be

ZeusZuki.

Well I checked my spare tcase tonight, the spare is, I was told, out of a 1989/90 Tracker. The speedo drive gear ratio is give or take a touch 3.75:1. If I make an approximate calculation using stock gearing and tyres then I don't get near that figure.

I reckon:

Stock tyre = 27"
Assume 1" of compression under load.
Effective diameter = 25"
Circumference = pi.d = 78.53"
There are 63360 inches in a mile
so in one mile the wheels will rotate 63360/78.53 = 806.72 turns
The final drive is 5:12 so the prop turns 5.12*806.72 = 4,130 turns
Divide by speedo gearing = 3.75
and you get 1101 turns per mile = 685 turns per km

With 33s and 5.83s it works out at  1045/650

Unless I've made an error in the calcs 

Lol, one of your bookmarks is that?

HaHaHa, no - Google is my friend!   

Well I checked my spare tcase tonight, the spare is, I was told, out of a 1989/90 Tracker. The speedo drive gear ratio is give or take a touch 3.75:1. If I make an approximate calculation using stock gearing and tyres then I don't get near that figure.

I reckon:

Stock tyre = 27"
Assume 1" of compression under load.
Effective diameter = 25"
Circumference = pi.d = 78.53"
There are 63360 inches in a mile
so in one mile the wheels will rotate 63360/78.53 = 806.72 turns
The final drive is 5:12 so the prop turns 5.12*806.72 = 4,130 turns
Divide by speedo gearing = 3.75
and you get 1101 turns per mile = 685 turns per km

With 33s and 5.83s it works out at  1045/650

Unless I've made an error in the calcs 

Honestly with most vehicles with gear driven speedos I haven't heard it referred to in gear ratios.  All Fords, GM's, Dodges, Jeeps, etc that I've dealt with have had the speedo gears referred to by the number of teeth the gear you can change has.  For example my Ranger had the 17 teeth gear stock and the one I switched to had 21 teeth.  I think because of the basic design, a small plastic gear, they don't worry much about gear mesh, patterns, coast, etc just that it fits.  In other words there's some slop built in.

That said I've never looked at the speedo gears on a Suzuki.  Are they plastic or metal?  Is there one gear or two gears that you remove?  The setups I've dealt with only had one gear you removed at the end of the speedo cable and/or sensor.

Have we even found out if there are other gears we can swap in to fix the readings?  When I asked I got a big "who knows?".

That said I've never looked at the speedo gears on a Suzuki.  Are they plastic or metal?  Is there one gear or two gears that you remove?  The setups I've dealt with only had one gear you removed at the end of the speedo cable and/or sensor.

Have we even found out if there are other gears we can swap in to fix the readings?  When I asked I got a big "who knows?".

The one I looked at today was a nylon gear. The speedo reading is OK its not too far out with the 5,83s but the EFI has a Vehicle Speed Sensor (VSS) built into the speedo head. I need to get the timing right in the ECU to measure the speed correctly. The VSS is used for several functions including fuel cut off and emission control. The numbers I have now will be close enough for the moment, I can fine tune it when its on the road.

Ever thought of an electronic fix for that?  That's what I'm doing with the GV.

Ever thought of an electronic fix for that?  That's what I'm doing with the GV.

yeah a new ECU 

http://www.btinternet.com/~j_holland