Speedo Correction

[franklin40]

as much as i was happy with the ratio converter fixing my speed i’ve had the cable break twice in the cold weather. it’s taken them 6 months each time to repair which is ridiculous. i’ve also spent more on shopping it back and forth than i paid for the converter. i’d look at a different company now that i’ve experienced it

 

[GA Architect]

Here is the converter I used.

 

[franklin40]

Here is the converter I used.
View attachment 2075517

that’s a better design than mine as it attaches straight to the tranny. mine has it in line. that’s why i think the cable has broken a couple times. if it does it again i’m going to get one like yours

 

[Rye356B]

My BJ42 came from Australia, so it's all in kilometers. I rely on my GPS to know how fast I'm going.

 

[-MaTTi-]

For example. On the stock 15 x 5.5” wheel my Maxxis Razr measure 32.5” at 32#

My KM2’s. Same wheel. Same truck. 31.5”

My KM3’s. Same wheel. Same truck 30.5”

Yep. 2” difference and all 33x10.50-15

What is your measuring technic?

 

[wngrog]

What is your measuring technic?

90* angle over center of the tire with a level on it.

 

[dgangle]

Here is the converter I used.
View attachment 2075517

where does this mount? Does this converter screw into the speedo drive housing on the output of the transfer case or do you have to have two cables and connect it between them?

Please post a picture if you can. I contacted Abbot and they were uncertain. $125 for the converter and $50 to spice the speedo cable

 

[GA Architect]

where does this mount? Does this converter screw into the speedo drive housing on the output of the transfer case or do you have to have two cables and connect it between them?

Please post a picture if you can. I contacted Abbot and they were uncertain. $125 for the converter and $50 to spice the speedo cable

-> click here: page 60 & post #1,183<-

Note: My correction syncro box is from Sacramento, CA - Commercial Speedometer

 

[-MaTTi-]

I tried to figure out what is the right speedo gear for my BJ42. Originally there was 16-teeth version. Now there is 35” tires coming, so speedo will be off about 10% (too less).

So no higher version (less teeth) seems to be available, only 17 which is worse than the original.

But I found that the gear allows 15-17 teeth, so there have to be smaller then.

Then I found this chart from page 2:

View attachment 182458View attachment 182459

And I happened to found the right part 33403-69055. So this would give about 6% higher reading, close enough.

 

[Living in the Past]

I tried to figure out what is the right speedo gear for my BJ42. Originally there was 16-teeth version. Now there is 35” tires coming, so speedo will be off about 10% (too less).
View attachment 2436771
So no higher version (less teeth) seems to be available, only 17 which is worse than the original.

But I found that the gear allows 15-17 teeth, so there have to be smaller then.
View attachment 2436772

Then I found this chart from page 2:

And I happened to found the right part 33403-69055. So this would give about 6% higher reading, close enough.

I'm hoping the same thing.

Just have to be sure you have the matching drive gear. Our FJ62 shows a different part number for drive gear. Seems to have to do with manual verses automatic transmission which seems odd since this is on the transfer case. Our FJ60 does have a the correct gear. 33481-60061 shows as a sub for 33481-60060.

 

[TLC Norway]

I tried to figure out what is the right speedo gear for my BJ42. Originally there was 16-teeth version. Now there is 35” tires coming, so speedo will be off about 10% (too less).
View attachment 2436771
So no higher version (less teeth) seems to be available, only 17 which is worse than the original.

But I found that the gear allows 15-17 teeth, so there have to be smaller then.
View attachment 2436772

Then I found this chart from page 2:

And I happened to found the right part 33403-69055. So this would give about 6% higher reading, close enough.

I'm hoping the same thing.
View attachment 2436869
Just have to be sure you have the matching drive gear. Our FJ62 shows a different part number for drive gear. Seems to have to do with manual verses automatic transmission which seems odd since this is on the transfer case. Our FJ60 does have a the correct gear. 33481-60061 shows as a sub for 33481-60060.

Happy updates now? I seem to remember my 15 gear is smaller OD than my 16.
Was it a direct swap?

 

[-MaTTi-]

Happy updates now? I seem to remember my 15 gear is smaller OD than my 16.
Was it a direct swap?

Mine was direct swap. It works, but I have not measured the real speed with GPS (not reg.plates yet).

 

[TLC Norway]

Mine was direct swap. It works, but I have not measured the real speed with GPS (not reg.plates yet).

Cool. I'll try mine and see if that does the trick.

 

[TLC Norway]

Mine was direct swap. It works, but I have not measured the real speed with GPS (not reg.plates yet).

Here's the 15t from an early splitcase, 1981, and a 17t from a late splitcase.

 

[Stubby]

Here is the converter I used.

Bumping this thread for anyone who might need some information....

I installed one of these units over the weekend (easy 5 minute job while I was waiting for my transmission oil to finish draining). My speedo is now spot on...

You can get them at SpeedometerCablesUSA.com (LINK). You'll need to do a comparison of your indicated speed on the dash to actual speed using GPS, then use the chart on the "Gearbox Adapters" page to figure out the correction factor you need.

NOTE: Actual speed / Indicated speed = correction RATIO.....NOT the % fast or slow. Pay attention to that when you're looking at the speed up / slow down correction factor. I goofed and originally ordered the wrong correction factor. They called me up after looking at my actual vs. indicated numbers and we got it squared away.

Give them a call and they'll help you figure out which configuration would work best for your rig. Had my unit in less than a week.....easy-peasy.

 

[-MaTTi-]

You can get them at SpeedometerCablesUSA.com (LINK).

How much do they charge for that?

 

[Stubby]

How much do they charge for that?

It was about $150, with tax and shipping.

 

[franklin40]

Bumping this thread for anyone who might need some information....

I installed one of these units over the weekend (easy 5 minute job while I was waiting for my transmission oil to finish draining). My speedo is now spot on...

You can get them at SpeedometerCablesUSA.com (LINK). You'll need to do a comparison of your indicated speed on the dash to actual speed using GPS, then use the chart on the "Gearbox Adapters" page to figure out the correction factor you need.

NOTE: Actual speed / Indicated speed = correction RATIO.....NOT the % fast or slow. Pay attention to that when you're looking at the speed up / slow down correction factor. I goofed and originally ordered the wrong correction factor. They called me up after looking at my actual vs. indicated numbers and we got it squared away.

Give them a call and they'll help you figure out which configuration would work best for your rig. Had my unit in less than a week.....easy-peasy.

i put one on my 62 and agree crazy easy and spot on accuracy. no speedometer needle bounce either that i found with another type of adapter that kept breaking. i’ll be ordering another one for my 40 in the new year!

 

[toyo84]

FWIW: Being that I run 32" tires and upgraded my 3rd members to 3.70 gears, my speedometer was obviously off. So after installing the new 3rds, I did a few test runs using GPS speeds vs the OEM speedometer. I took the GPS speed and divided by the OEM speedometer, and that was my ratio for a correction device. For my rig, I ran the speedo up to 40 and the GPS was a 48. The I ran the speedo up to 50 and the GPS was at 60. Thus my calculation were 48/40 and 60/50 which equaled 1.20 as my correction ratio.

I did a lot of research on MUD and found a company out of Sacramento, CA - Commercial Speedometer. Gave them a call, talked to Chuck, and he built me a Correction Syncro box and shipped it out that night. Great guy to work with!!! It arrived 2 days later, and for $85 bucks shipped from west coast to east coast, BARGAIN!.....And let me just say, it is nice knowing that when I'm looking at my Gauge Cluster, my speedometer is actually a useful device now.

View attachment 2075486

Hi, understanding that this is an old post.
I have a similar issue, and think this might be the solution for me. Since i am residing in Germany, I wonder if somebody out there can give me an emailaddress of Commercial Speedometer? I surely hope somebody replies to my question.
Thanks a lot! Marc

 

[Stubby]

Hi, understanding that this is an old post.
I have a similar issue, and think this might be the solution for me. Since i am residing in Germany, I wonder if somebody out there can give me an emailaddress of Commercial Speedometer? I surely hope somebody replies to my question.
Thanks a lot! Marc

The website just has a "contact us" section, but all of my communication, as well as my purchase invoice came from deluxespeedometer@hotmail.com

Try that e-mail address and see if you get a reply.
.