A friend has a problem that may relate to the TT Truck Rear Axle Ratio.
His TT Truck goes slower than most with a top speed of 12 miles per hour.
The rear axle ratio must be printed someplace, but I cannot find it.
The Model A used the same rear axle with different wheels.
Would that axle in a Model T make it run slower?
TT Truck Rear Axle Ratio
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Daisy Mae
- Posts: 348
- Joined: Mon May 06, 2024 9:32 pm
- First Name: Kurt
- Last Name: Andersson
- * REQUIRED* Type and Year of Model Ts owned: 1914 Touring
- Location: Panama City Beach, FL
Re: TT Truck Rear Axle Ratio
There were two axle ratios provided on the TT...
7.25:1 or 5.17:1.... so, "slower than most"... most what? T cars... YES... the TT is MUCH slower than a car to enable to haul it's tonnage. Slower than most TT's? Depends on who has what axle ratio. I had a TT with the "fast" axle 5:1, and best I could push it was 20mph. A TT with the 7:1 you could probably run alongside it while the truck was full throttle! So 12-15 is normal. Which is why an auxiliary tranny with overdrive like a Warford helps the trucks.
The AA only used the worm 28 into 29 (with basically same ratios as the TT) before changing to ring & pinion. While basically similar design, the AA housing had a cast mark up top along the worm side denoting high vs low speed gearing with an A or B. The TT however had no such casting mark.
7.25:1 or 5.17:1.... so, "slower than most"... most what? T cars... YES... the TT is MUCH slower than a car to enable to haul it's tonnage. Slower than most TT's? Depends on who has what axle ratio. I had a TT with the "fast" axle 5:1, and best I could push it was 20mph. A TT with the 7:1 you could probably run alongside it while the truck was full throttle! So 12-15 is normal. Which is why an auxiliary tranny with overdrive like a Warford helps the trucks.
The AA only used the worm 28 into 29 (with basically same ratios as the TT) before changing to ring & pinion. While basically similar design, the AA housing had a cast mark up top along the worm side denoting high vs low speed gearing with an A or B. The TT however had no such casting mark.
Last edited by Daisy Mae on Sun Apr 27, 2025 10:05 am, edited 9 times in total.
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George House
- Posts: 2814
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- First Name: George
- Last Name: House
- * REQUIRED* Type and Year of Model Ts owned: ‘10 Maxwell AA, ‘11Hupp Model 20, Two 1914 Ford runabouts, 19 centerdoor, 25 C Cab,26 roadster
- Location: Northern Caldwell County TX
- MTFCA Life Member: YES
- Board Member Since: 1999
Re: TT Truck Rear Axle Ratio
Google: mtfca TT rear axle ratio……plenty of discussion
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Allan
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- First Name: Allan
- Last Name: Bennett
- * REQUIRED* Type and Year of Model Ts owned: 1912 van, 1917 shooting brake, 1929 roadster buckboard, 1924 tourer, 1925 barn find buckboard, 1925 D &F wide body roadster, 1927LHD Tudor sedan.
- Location: Gawler, Australia
Re: TT Truck Rear Axle Ratio
On our Canadian sourced vehicles the square plate at the back of the worm drive was usually stamped wit a 5 or a 7 to indicate the diff. ratio.
Allan from down under.
Allan from down under.
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Cap
- Posts: 86
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- First Name: Cap
- Last Name: Weir
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- Location: Atascadero,Ca
Re: TT Truck Rear Axle Ratio
'My' TT was a Texas Truck, and was mostly Garaged until Dad and I brought it to California.. It had the 7:1 Rear.. top speed with a Cast Iron Warford was 18 MPH..
Dad then Found a 'Very Used' set of 5:1 Gears.. Upon installing them. he could get to 42-45 MPH.. Only Stock Brakes..
We went to Rocky Mtn Brakes.. Helped a lot.. But to make the Thing more 'Derivable', Dad went with the 'Lane Worford' Transmission.. It bolted in.. But the Low range was not as low, and the High Range was not as High.. so Top Speed went to about 38 if you push it..
I have the Truck now, and about 35 is as fast as I push it.. I use it as a Truck, as its my Only Truck.. so it goes to the Dump and the Lumber Yard..
I liked the Top Speed with the Cast Iron Warford, but I was never able to 'Shift on the Fly' with it ( Some can, I cant ) so the Lane Warford has stayed in the Truck..
When I drive the Truck, I Take off in Low Gear Worford, and Low Peddle.. Then Shift to High Warford, and then accelerate again in Low Peddle.. Then Jump into High Peddle.. So I drive it like a 3 Speed Transmission.. Takes a while to get it, but now it's just habit..
It also has a Scatt Crank, and an E-Timer.. Its a Sweet Ride.. AND I Hand Crank Start it always..
Cap
Dad then Found a 'Very Used' set of 5:1 Gears.. Upon installing them. he could get to 42-45 MPH.. Only Stock Brakes..
We went to Rocky Mtn Brakes.. Helped a lot.. But to make the Thing more 'Derivable', Dad went with the 'Lane Worford' Transmission.. It bolted in.. But the Low range was not as low, and the High Range was not as High.. so Top Speed went to about 38 if you push it..
I have the Truck now, and about 35 is as fast as I push it.. I use it as a Truck, as its my Only Truck.. so it goes to the Dump and the Lumber Yard..
I liked the Top Speed with the Cast Iron Warford, but I was never able to 'Shift on the Fly' with it ( Some can, I cant ) so the Lane Warford has stayed in the Truck..
When I drive the Truck, I Take off in Low Gear Worford, and Low Peddle.. Then Shift to High Warford, and then accelerate again in Low Peddle.. Then Jump into High Peddle.. So I drive it like a 3 Speed Transmission.. Takes a while to get it, but now it's just habit..
It also has a Scatt Crank, and an E-Timer.. Its a Sweet Ride.. AND I Hand Crank Start it always..
Cap