JMI Motorized Universal Wheeley Bar Drive Unit — Add-On for Heavy-Duty Wheeley Bars

Product Overview

The JMI Motorized Universal Wheeley Bar drive unit adds powered movement to a Heavy-Duty Universal Wheeley Bar. It replaces the front section of an existing heavy-duty bar with a 12-volt motorized drive assembly, so a fully assembled tripod-mounted telescope travels between storage and the observing pad under power rather than by hand. The unit ships with 10″ pneumatic tires, a tow handle, a steel battery pack holder and a 5/8″ variable speed dial, and weighs 34 lb. JMI builds it in the USA.

Who It's For

This is a good match if you already own a Heavy-Duty Universal Wheeley Bar in its 10″ pneumatic tire configuration and would rather the roll-out happened under power — a heavy imaging rig, a long run between the garage and the observing pad, or a setup where moving a loaded tripod by hand takes more effort than you want to spend on it.

Key Features & Design

• 12-volt powered drive: A motorized drive unit moves the loaded bar under its own power.
• Variable speed control: A 5/8″ speed dial sets the travel rate.
• 10″ pneumatic tires: Air-filled tires are included with the unit and carry the load over uneven ground.
• Tow handle: Included for steering the bar as it travels.
• Steel battery pack holder: Included, and carries the 12-volt battery that powers the drive.
• Welded steel construction: The drive unit is welded steel, matching the Wheeley Bar frame it joins.
• Built in the USA: Designed and manufactured by JMI.

Mechanical Design

The motorized unit is not bolted on alongside the existing bar — it takes the place of the front section of a Heavy-Duty Wheeley Bar. The drive assembly, its two 10″ pneumatic tires and the battery holder arrive as one front-end module, and the rear section of the original bar stays as it is. Because the drive sits at the front and the tow handle steers from the same end, the loaded telescope tracks behind the powered wheels instead of being pushed from the rear. The 5/8″ speed dial feeds the 12-volt motor, so travel speed is set by the dial rather than by how hard the bar is pushed.

Recommended Uses

• Rolling a fully assembled imaging rig from a garage or shed out to a backyard pad under power
• Moving a heavy mount, OTA, cameras and cabling in one trip without breaking the setup down
• Covering longer distances between storage and the observing position than are comfortable to push by hand
• Observatory workflows where the telescope is rolled out and back on a regular schedule
• Setups where the loaded weight of the rig makes a hand-pushed bar hard to start and stop

Compatibility and Accessory Notes

JMI publishes this drive unit in three fitments, each matched to the bar it joins: TPWMTR-MEDHD for the Heavy-Duty Medium Wheeley Bar, TPWMTR-LG for the Heavy-Duty Large Wheeley Bar, and TPWMTR-AP for the Astro-Physics pier mount Wheeley Bar. All three call for the host bar to be in its 10″ pneumatic tire configuration. JMI also lists a TPWMTR version for Heavy-Duty Shorty owners and asks that Shorty fitment be checked with them before an order is placed. The unit powers the bar; the telescope, mount, tripod and the Wheeley Bar itself are separate items. Tell us which Wheeley Bar you own and which tires are on it, and we'll confirm the fitment and sort the right version for you.

Good to Know Before You Order

• This is an add-on rather than a complete Wheeley Bar. JMI states plainly that the motorized unit is an add-on and replaces the front section of an existing Heavy-Duty Wheeley Bar. A bar is needed for it to attach to, and is bought separately.
• The host bar uses the 10″ pneumatic tire configuration. The drive unit is built around that setup, so bars on other wheel options are outside its published fitment.
• The battery is not included. JMI recommends a 12-volt battery of 17 amp-hours or greater. It is chosen and supplied separately.
• The unit weighs 34 lb on its own. That is the drive module by itself, before the bar, mount or telescope are counted.
• Fitment is version-specific. The Medium Heavy-Duty, Large and Astro-Physics pier versions are distinct items rather than one adjustable unit.
• Installation is done by the owner. JMI quotes 15 to 30 minutes with basic hand tools.

Frequently Asked Questions

Is it difficult to install?

JMI quotes 15 to 30 minutes using basic hand tools. The unit replaces the front section of the existing bar, so the work is removing that section and fitting the drive module in its place.

Does this replace my Wheeley Bar, or work with it?

It works with it. The drive unit becomes the front section of a Heavy-Duty Wheeley Bar you already own; the rear section of that bar stays in service.

What battery does it take?

A 12-volt battery, with JMI recommending 17 amp-hours or greater. The steel holder that carries it is included; the battery itself is not.

How is the speed controlled?

Through a 5/8″ speed dial on the unit, which gives variable speed rather than a single fixed rate.

Which version fits my bar?

TPWMTR-MEDHD suits the Heavy-Duty Medium bar, TPWMTR-LG the Heavy-Duty Large, and TPWMTR-AP the Astro-Physics pier mount version. Shorty fitment is checked with JMI first. We are happy to match it to your bar if you tell us the model.

What comes in the box?

The motorized drive unit, 10″ pneumatic wheels, the tow handle, the steel battery pack holder and the 5/8″ speed dial.

Bottom Line

In short: this is the 12-volt powered front end for a Heavy-Duty Universal Wheeley Bar, supplied with 10″ pneumatic tires, tow handle, battery holder and variable speed dial at 34 lb, and built by JMI in the USA. Paired with the bar it is made for, it turns the roll-out into a powered trip.