JMI Heavy-Duty Large Universal Wheeley Bar — Telescope Dolly

Product Overview

The JMI Heavy-Duty Large Universal Wheeley Bar is the widest span in JMI's heavy-duty Universal line, built for the wide-leg tripods that carry observatory-class mounts. It is rated for 300 lb total — tripod, mount, OTA and accessories combined — and adjusts to tripods measuring 49″ to 56.5″ tip to tip. Foot receptacles have a 2-3/4″ inside diameter and accept feet up to 2-3/4″ across. It rides on 5″ polyurethane locking wheels with 5/8″ heavy-duty leveling screws, on a welded steel frame with a powder-coat finish. Made in the USA, 37 lb as shipped.

Who It's For

This is a good match if your tripod opens to a wide stance — 49″ to 56.5″ between foot tips at observing height — and the rig stays assembled between sessions; if the combined weight of tripod, mount, counterweights and optics falls under 300 lb; and if you would rather roll the whole assembly out to a pad than break it down and rebuild it. The wide stance also puts the eyepiece higher off the ground than the narrower bars do, which suits long refractors and large catadioptrics.

Key Features & Design

• 300 lb load rating: Covers the tripod, mount, counterweights, optical tube and everything bolted to it.
• 49″–56.5″ tip-to-tip range: The widest span JMI offers in the Universal series.
• 2-3/4″ foot receptacles: Sized for the large feet on observatory-class tripods, up to 2-3/4″ in diameter.
• 5″ polyurethane locking wheels: Standard rather than an upgrade, and they cross expansion joints and cracked concrete without stalling.
• 5/8″ heavy-duty leveling screws: The heavier thread matched to the 300 lb rating.
• Welded steel frame: Powder-coated welded steel, made in the USA, 37 lb as shipped.
• 10″ pneumatic option: The 5/8″ version of JMI's 10″ all-terrain tire upgrade fits this bar and raises the setup about 3.5″.

Mechanical Design

The frame is a welded steel spider with long adjustable arms, each ending in a cup that captures one tripod foot. Nothing bolts to the tripod — the mass of the loaded rig seats the feet in the cups and holds the geometry. Each arm carries a locking 5″ polyurethane caster and a 5/8″ leveling screw. The casters take the load while the rig is rolling; at the observing position the leveling screws thread down until the frame lifts clear of the wheels, which puts the rig on rigid steel feet rather than rubber and levels the base on a sloped pad. Because the arms reach out to 56.5″, the footprint is broad enough to keep a tall, wide-stance tripod stable through the move.

Recommended Uses

• Rolling a wide-stance observatory-class tripod out of a garage or roll-off shed onto a concrete pad.
• Moving a large refractor or catadioptric on a heavy equatorial mount with counterweights fitted.
• Keeping an assembled rig on a fixed pad position so alignment and cabling survive between sessions.
• Repositioning a large setup mid-session to clear an obstruction on the horizon.
• Shifting a permanent-style setup indoors when weather closes in.

Compatibility and Accessory Notes

Fit is set by the tripod's tip-to-tip measurement at observing height, taken between any two feet: this bar covers 49″ to 56.5″. The receptacles are 2-3/4″ inside diameter and accept feet up to 2-3/4″. Narrower tripods are covered by the Heavy-Duty Medium at 34″–42.5″ and the Heavy-Duty Shorty at 26.25″–31.25″, both rated to the same 300 lb. This bar uses 5/8″ leveling screws, so the 5/8″ versions of JMI's 10″ pneumatic wheel upgrade, tow handle, speed-dial drill adapter, replacement leveling screws and soft-ground feet are the matching parts; accessories listed for 1/2″ leveling screws belong to the standard-duty bars. Tie-down bracket kits are sold separately. Tell us the make and model of your tripod and we will confirm the fit.

Good to Know Before You Order

• The span is what separates this model from the HD Medium. Both carry 300 lb; this one covers 49″ to 56.5″ and the HD Medium covers 34″ to 42.5″, so the tripod's stance decides which applies.
• The wide stance needs room at the door. With the 10″ pneumatic tires fitted, JMI's published allowance is a doorway at least 3″ wider than the tip-to-tip distance.
• The 300 lb rating is for everything on the bar. Tripod, mount, counterweights, optical tube, cameras and power supplies all count toward it.
• The 10″ upgrade changes the working height. It raises the setup about 3.5″, which shifts the eyepiece position and the tip-to-tip figure to measure against.
• 5/8″ leveling screws set the accessory version. The 1/2″ accessories in the JMI range fit the standard-duty bars rather than this one.
• Weight as shipped is 37 lb. The bar arrives as a welded steel frame in one carton.

Frequently Asked Questions

Is it difficult to set up?

The frame arrives welded and ready. Setup is a matter of opening the arms to the tripod's tip-to-tip measurement, lowering the feet into the cups, and running the 5/8″ leveling screws down once the rig is parked. Nothing on the tripod is drilled or modified.

How is tip-to-tip distance measured?

With the tripod at observing height, the measurement runs between any two foot tips. This bar covers 49″ through 56.5″.

Will it fit a narrower tripod?

The arms close to 49″. Tripods that measure less than that at observing height fall to the HD Medium, which covers 34″ to 42.5″ at the same 300 lb rating.

Does polar alignment survive the trip?

The tripod is never taken apart, so alignment, cable routing and counterweight position stay as they were. Marking the tripod position on the pad reproduces the same alignment closely on the next run.

What surfaces does it roll on?

The standard 5″ polyurethane wheels handle concrete, asphalt, pavers and cracked driveways. Grass, gravel, mulch and sand are the ground the 10″ pneumatic upgrade is made for.

Bottom Line

In short: a 300 lb welded steel dolly on 5″ locking polyurethane wheels and 5/8″ leveling screws, spanning 49″ to 56.5″ tip to tip — the widest Universal Wheeley Bar JMI builds, for wide-stance tripods carrying observatory-class rigs. Made in the USA, 37 lb as shipped.