Speedo Cable Ratio

All things body, interior, paint, windows, tops... you know.
Post Reply
Stekay
United States of America
Posts: 346
Joined: Thu Sep 01, 2011 8:32 pm
Location: Long Island, New York

Speedo Cable Ratio

Post by Stekay »

Does anyone know the ratio of the speedometer cable to the axle revolutions?
'76 710K
Stekay
United States of America
Posts: 346
Joined: Thu Sep 01, 2011 8:32 pm
Location: Long Island, New York

Re: Speedo Cable Ratio

Post by Stekay »

Wow 74 vies and no responses. Sometimes its just "your" turn. Good to know there's always new things to share with my fellow Pinzer's.

Answer: ~2.25 speedo turns to 1 axle turn.
'76 710K
krick3tt
Posts: 2457
Joined: Thu Mar 16, 2006 6:48 pm
Location: Denver, CO USA

Re: Speedo Cable Ratio

Post by krick3tt »

What relevance does this ratio have? Why is it important unless you are designing a vehicle.
The tire still turns 1 time no matter how large or small the tire. It just goes farther with a larger tire and therefore changing the tire
size throws off the speedo in a stock vehicle tire when changed to larger tire.
Any man who thinks he can be happy and prosperous by letting the government take care of him:
better take a closer look at the American Indian.---Henry Ford
Stekay
United States of America
Posts: 346
Joined: Thu Sep 01, 2011 8:32 pm
Location: Long Island, New York

Re: Speedo Cable Ratio

Post by Stekay »

If you want to change your speedometer to an alternative mechanical speedo or an electric speedo using a pulse generator, you need to know the ratio to calibrate an electric or match a mechanical speedo. BTW, for reference the right angle gearbox is 1:1.

http://www.isspro.com/installation/IS073.pdf
'76 710K
undysworld
Norway
Posts: 1776
Joined: Fri Apr 16, 2004 8:08 am
Location: Blue Mounds, WI

Re: Speedo Cable Ratio

Post by undysworld »

I think for most folks, the question has never arisen, and therefore they have no clue nor ready answer. From my experience, the electronic versions have alternate methods of calibration, and I expect those are necessary given different tire diameters.

I am surprised that the 90 degree adaptor is 1:1, as I had read previously that it was a reduction gear. But live and learn.
undysworld
Norway
Posts: 1776
Joined: Fri Apr 16, 2004 8:08 am
Location: Blue Mounds, WI

Re: Speedo Cable Ratio

Post by undysworld »

BTW, for reference the right angle gearbox is 1:1.
Well, it was bugging me, but I've found the earlier post which stated that the angle adaptor is a gear reduction:
No question you can run it without the 90. Your speed will be off as it is a reduction for the tires. Add big enough tires and you might not need the reductio
http://www.real4x4forums.com/PinzgauerB ... +reduction

That's a quote from Scott Ingham, who I'd expect to be correct about it.

Not trying to start a fight here, just clarify the answer. Where's Mythbusters when we need 'em?
Stekay
United States of America
Posts: 346
Joined: Thu Sep 01, 2011 8:32 pm
Location: Long Island, New York

Re: Speedo Cable Ratio

Post by Stekay »

Well I can assure you that mine is 1 to 1. Obviously it's really easy to check. It's a VDO unit with the #'s 1.0.888 & 33/4616 embossed on the end cap.
Usually 2 to 1 adapters are for Tachometer drive's that aren't off the camshaft.
'76 710K
User avatar
4x4Pinz
United States of America
Posts: 1029
Joined: Sat Oct 24, 2009 6:17 pm
Location: arizona

Re: Speedo Cable Ratio

Post by 4x4Pinz »

it would seem if you are correct and your angle is 1:1 that there are different drive boxes. When I removed mine the speedometer read closer to accurate with the larger then stock tires. To me that would indicate that the drive box had some sort of reduction involved or the speed would have read the same with or without the box installed, assuming a 1:1 ratio. Does not really matter as I switched to the electric units so I could calibrate them to read correctly and in MPH.
Stekay
United States of America
Posts: 346
Joined: Thu Sep 01, 2011 8:32 pm
Location: Long Island, New York

Re: Speedo Cable Ratio

Post by Stekay »

I know there are various ratio boxes available, but they're usually not angle boxes. I believe there is a box specifically for KPH to MPH. All good things to know.
'76 710K
undysworld
Norway
Posts: 1776
Joined: Fri Apr 16, 2004 8:08 am
Location: Blue Mounds, WI

Re: Speedo Cable Ratio

Post by undysworld »

There must be various units out there. I just chucked one up in a drill and marked the orientation of the chuck and adaptor output. If I counted it right, it was 8:9 ration. It is a right angle adaptor. I'll bring it home and post the part numbers later.
Stekay
United States of America
Posts: 346
Joined: Thu Sep 01, 2011 8:32 pm
Location: Long Island, New York

Re: Speedo Cable Ratio

Post by Stekay »

it was 8:9 ratio
Mine might be that as well. It was a fraction off over one turn, but I chalked that up to old eyes. :roll:
'76 710K
undysworld
Norway
Posts: 1776
Joined: Fri Apr 16, 2004 8:08 am
Location: Blue Mounds, WI

Re: Speedo Cable Ratio

Post by undysworld »

Mine might be that as well. It was a fraction off over one turn, but I chalked that up to old eyes.
Ahh! I'm dying laughing here. I'd considered commenting that it seemed so small a difference as to maybe be imperceptible without actually counting. But I didn't want to insult anyone.

I counted three times before I trusted my own (old) eyes. Pretty easy to miss.

FWIW, my (old) brain completely forgot to bring home the part number/s...

Interestingly, it's not shown at all here: http://www.pinzgauer.com/parts.php?cat= ... view=03-15 :?: :?: :?:
Post Reply