Correct speedo turtle

M

my4dv8

Well-known member
We have an banjo rear with original 3.54 merc gears and 750 x 16 rear tires.
I have several 19 tooth speedometer turtles. I think 18 maybe the correct number for us, but please correct me if i am wrong . I usually am>>>
Thanks.
 
my4dv8 said:
We have an banjo rear with original 3.54 merc gears and 750 x 16 rear tires.
I have several 19 tooth speedometer turtles. I think 18 maybe the correct number for us, but please correct me if i am wrong . I usually am>>>
Thanks.
Click to expand...

No no, no. V8ers are often mistaken, but we're never wrong.
 
I put 3.54 rear gears in my 35 fordor sedan with 600 x 16 tires, and a #18 turtle, w/18 tooth gear. This has the speedometer reading correctly based on what my GPS is saying. With 750 × 16 tires, you might get close to being correct with a 17 tooth gear.
 
Last edited:
Try Bratton's, Bratton's Ford Parts, (301) 829-9880.

Charlie Stephens
 

Attachments

  • Screen Shot 2018-10-28 at 7.25.17 PM.jpg
    Screen Shot 2018-10-28 at 7.25.17 PM.jpg
    18.8 KB · Views: 40
Quick chart, print or save. I need to add it to my photo albums as this comes up about twice a yr and I wouldn't have to look for it. 7.50s x 16s are not there, so no help to you. But maybe others. A 18 will get you close enough to maybe avoid a ticket. :)


As mentioned: Model a turtle gears 18s will work also. Maybe they have 17s (did ford make 17s????)

https://www.brattons.com/
 

Attachments

  • SPEEDO CHART.jpg
    SPEEDO CHART.jpg
    190.9 KB · Views: 187
Last edited:
Some folk are saying just fitting a 17 tooth gear wont cut it as the diameter is smaller and when fitted to a regular turtle as the gear mesh is incorrect. Any bright sparks throw some insight on this as fact or fallacy.
 
my4dv8 said:
Some folk are saying just fitting a 17 tooth gear wont cut it as the diameter is smaller and when fitted to a regular turtle as the gear mesh is incorrect. Any bright sparks throw some insight on this as fact or fallacy.
Click to expand...

As long as the gear mesh is sufficient to prevent gears from slipping cogs, the diameter is of no consequence, as there would still be the same number of cogs to the full circle.
 
I am using a 17 tooth gear from Braxton in an 18 turtle and the gear engages the worm on the drive shaft okay. I left out the gasket to get it a couple thousandths closer. With 26.5" diameter tires and 3.25 rear end gears, the speed is pretty close to the GPS.
 
I called Bratton's a few weeks ago. They are using an aftermarket turtle. They use the same turtle for an 18 tooth and 19 tooth. They said that you can buy their bare turtle. They also said that if you put a 17 tooth gear in it it will not engage the drive gear sufficiently. If it is true what I have read on this forum that you can drop one size then I suspect that Bratton's new turtle is a 19. Bratton sells a 17 gear but not a turtle for it.
 
hellmet said:
how do you press the gear out ? got a 18 turtle and got new 17 gear.
Click to expand...


hellmet....Here is the picture I promised you last night. Note the little bushing-like piece at the lower right. It starts-out surrounding and supporting the end of the shaft, right next to the threads where the speedo cable goes. Once you carefully pry it out of the housing and off of the shaft, you've got it made. DD


92291
 
I just went through this and this is what i did and so far it has worked. I bought the 17 tooth gear from Brattons and a turtle from Macks. It had no markings on it but was assured it would work. Surprise it didn't. It promptly ate up the gear. I got a new gear installed it in turtle put grease on both the turtle gear and drive shaft gear took transmission out of gear,spun a rear wheel and took the turtle off to see how they meshed. Then i found some metal pipe of the same OD as the drive shaft, wraped it around the pipe with sandpaper and proceded to sand the turtle. After some time i was able to bring the gear down to make a good match and the turtle retained its original shape.
 
Heavy Duty said:
I just went through this and this is what i did and so far it has worked. I bought the 17 tooth gear from Brattons and a turtle from Macks. It had no markings on it but was assured it would work. Surprise it didn't. It promptly ate up the gear. I got a new gear installed it in turtle put grease on both the turtle gear and drive shaft gear took transmission out of gear,spun a rear wheel and took the turtle off to see how they meshed. Then i found some metal pipe of the same OD as the drive shaft, wraped it around the pipe with sandpaper and proceded to sand the turtle. After some time i was able to bring the gear down to make a good match and the turtle retained its original shape.
Click to expand...

So machine down a turtle tell gears get a good mesh. That is what i will try
 
You must log in or register to reply here.
Back
Top