Dodge invented the shaft-mount reducer in 1949 with the original Torque-Arm. More than 75 years and roughly 10 million units later, there are three Torque-Arm reducers in the line, and the question we hear most from customers is a fair one: why three?
Because they do three different jobs. They overlap on paper, but each one is the right answer in a different situation. Here's how we sort them when we're standing at your drive.
The TXT is the reducer already hanging off the head shaft at a lot of Florida aggregate plants. It has the biggest installed base in the family, maintenance crews know it, and the spares shelf is usually stocked for it. That familiarity is its biggest strength.
Best at: Like-for-like replacement. It also covers the top of the range: fourteen sizes, with the largest rated to 1,000,000 inch-pounds, and bores up to 10 inches. Versions are built for screw conveyors (SCXT) and hydraulic drives (HXT).
Where it belongs: Aggregate and mining plants that have run TXT for years and want the same footprint, accessories and spares back. Inch-size North American plants.
What's new: In 2023 Dodge upgraded the line to TXT-E. The backstop has at least double the holding power of earlier generations and is designed to operate in EP lubricant. The gear case comes drilled and tapped, so bushing covers bolt on without modification, and shaft guards install with basic hand tools. The nameplate is digitized with a QR code, so the specs don't disappear when somebody tears the tag off.
Keep in mind: TXT is inch-only. For brand-new installations Dodge generally steers customers toward Torque-Arm II unless there's a reason to stay with TXT.
Torque-Arm II was Dodge's redesign of the Torque-Arm, and its headline is power density. It carries the highest torque rating per case size in the family. In practice, a size 7 Torque-Arm II rates roughly where a size 8 TXT does. One case size smaller for the same job means a lighter reducer on the shaft and often a smaller belt drive.
Best at: New drives. Twelve case sizes up to 400 HP, five ratios per size, inch and metric bores up to 7 inches. Dual sealing on every shaft, with metal-reinforced seals behind an external shield and excluder lip, and tapered roller bearings throughout. The same gearbox becomes a screw conveyor drive with an adapter kit, and it shares accessories with the Motorized Torque-Arm II.
Where it belongs: New installations, OEM equipment, newer bulk plants, and grain handling, where it's the dominant reducer. It's also our usual first choice when replacing another brand's shaft-mount unit, because its short-shaft bushing fits where the existing shaft doesn't leave much room. Today it's the majority of Dodge's Torque-Arm sales.
Keep in mind: Shafts top out at 7 inches. On screw conveyors, drive shafts are not interchangeable between the TXT screw conveyor version and Torque-Arm II, so switching families means a new drive shaft. The end that goes into the screw follows the CEMA standard, so the trough end stays the same.
Dodge built the Motorized Torque-Arm II by adding a bevel gear set to the input of the Torque-Arm II, making it a right-angle reducer the motor bolts straight onto. No sheaves, no V-belts, no belt guard.
Best at: Getting the belt drive off the catwalk. Nothing to align or re-tension, no belts to replace, far less guarding, and no belt pull loading the input shaft. It's designed to AGMA standards for a 5,000-hour L10 bearing life, and Dodge describes it as the only AGMA-rated direct-drive reducer on the market. Ten sizes support drive packages up to 329,000 lb-in of torque. On sizes 7 through 12, Dodge's Atlas adapter takes standard foot-mount motors in 364T to 447T frames, up to 200 HP.
Where it belongs: Fixed-speed conveyors, high-traffic catwalks, plants working to reduce guarding and belt-drive maintenance, recycling operations, and newer plants.
Keep in mind: You can't change speed with a sheave swap, so plan on a VFD if speed needs to move. Bushing choices are narrower than on Torque-Arm II, because direct drive puts different loads on the driven shaft. If the bushing you need isn't offered, the reducer is probably too big for that shaft, and it's time to bring in Dodge's application engineers.
| If this describes your drive… | Start with |
|---|---|
| Replacing a TXT and want the same footprint, accessories and spares | TXT-E |
| Shaft over 7 inches, or torque beyond Torque-Arm II's range | TXT-E |
| New drive, or replacing another brand's shaft-mount reducer | Torque-Arm II |
| Metric bores, or one spare to cover belt and screw conveyors | Torque-Arm II |
| Conveyor runs one speed and you want the belts and guard gone | Motorized Torque-Arm II |
| Speed changes with production and there's no VFD | A belt-driven TXT-E or Torque-Arm II |
Every Torque-Arm reducer is built at Dodge's gear plant in Greenville, South Carolina. They're all sized the same way: motor nameplate horsepower and RPM at the driven shaft, with a 1.4 service factor for standard bulk-handling conveyors and 2.0 for severe or critical duty. And every one of them ships without oil, with a yellow tag that says so. Fill it for the mounting position before startup, because too little oil isn't much better than none.
Davis Industrial is an authorized Dodge distributor. Our solutions specialists work directly with Dodge's application engineering team, so a selection can be checked while we're still standing at your drive. Bring us photos of the drive, the motor nameplate and the reducer nameplate, and we'll take it from there.
Schedule a free site walk, or call 813-247-3620.