JMI Astro-Physics Pier Mount Wheeley Bars

Product Overview

The JMI Astro-Physics Pier Mount Wheeley Bars are built for Astro-Physics pier mounts rather than for adjustable-leg tripods. The set carries 300 lb total — pier, mount, OTA and accessories combined — on a welded steel frame with 5″ polyurethane locking wheels and 5/8″ heavy-duty leveling screws. JMI lists the fit as Astro-Physics 6″, 8″ and 10″ pier mounts, covering the AP 400, 600, 800, 900 and 1200. The footprint matches the HD Medium Wheeley Bar, in heavier-duty construction, and the frame sets up at three widths: 29″–34″ at its narrowest, 33″–40″ in the normal setting and 38″–47″ at its widest. Made in the USA, 34 lb as shipped.

Who It's For

This is a good match if you own an Astro-Physics pier mount and store the pier, mount and optical tube assembled; if you would rather roll the complete rig between a garage or shed and an observing pad than break the pier down each session; and if the combined weight of pier, mount, counterweights and optics falls under 300 lb. It suits a routine where the same setup returns to the same marked spot night after night with alignment and cabling untouched.

Key Features & Design

• Purpose-built for AP piers: Fits the Astro-Physics 6″, 8″ and 10″ pier mounts used under the AP 400, 600, 800, 900 and 1200.
• 300 lb load rating: Covers the pier, mount, counterweights, optical tube and everything bolted to it.
• Three width settings: 29″–34″ narrowest, 33″–40″ normal and 38″–47″ widest, so the stance can be matched to the doorway and the pad.
• 5″ polyurethane locking wheels: Standard equipment, and they cross expansion joints and cracked concrete without stalling.
• 5/8″ heavy-duty leveling screws: The heavier thread used across JMI's heavy-duty line.
• Heavier-duty frame: The HD Medium footprint in a heavier build, welded steel with a powder-coat finish, made in the USA, 34 lb as shipped.

Mechanical Design

A pier presents a fixed base rather than three adjustable legs, so this set takes the load through a welded steel frame sized to the AP pier footprint instead of through foot cups on splayed tripod arms. Each arm carries a locking 5″ polyurethane caster and a 5/8″ leveling screw. The casters take the weight while the rig is rolling; at the observing position the leveling screws thread down until the frame lifts clear of the wheels, putting the pier on rigid steel points rather than rubber and levelling the base on a sloped pad. The three width settings change the outside envelope of the loaded assembly, which is what governs whether it clears a doorway on the way out.

Recommended Uses

• Rolling an assembled Astro-Physics pier, mount and optical tube from a garage bay onto a concrete observing pad.
• Returning a pier-mounted rig to a marked pad position session after session with alignment and cabling intact.
• Moving a pier-mounted imaging setup indoors when weather closes in, without stripping the imaging train.
• Repositioning a heavy pier setup on the pad to clear a tree line or a roofline.
• Storing an AP pier rig in a shed or roll-off building and wheeling it out at the start of each session.

Compatibility and Accessory Notes

JMI lists the fit as Astro-Physics 6″, 8″ and 10″ pier mounts, covering the AP 400, 600, 800, 900 and 1200. The footprint matches the HD Medium Wheeley Bar in heavier-duty construction, and the frame sets to 29″–34″, 33″–40″ or 38″–47″ in width. Adjustable-leg tripods are covered instead by the Universal series: the Heavy-Duty Shorty at 26.25″–31.25″, the Heavy-Duty Medium at 34″–42.5″ and the Heavy-Duty Large at 49″–56.5″, all rated to 300 lb. This set uses 5/8″ leveling screws, so the 5/8″ versions of JMI's 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 which Astro-Physics pier and mount you are running and we will confirm the fit.

Good to Know Before You Order

• This set is matched to AP piers rather than tripods. Adjustable-leg tripods are the Universal series' territory, and those bars use foot cups sized to tripod feet.
• The 300 lb rating is for everything on the frame. Pier, mount, counterweights, optical tube, cameras and power supplies all count toward it.
• The width setting governs doorway clearance. The frame runs 29″–34″ at its narrowest and 38″–47″ at its widest, so the route out of the building decides which setting is workable.
• 5/8″ leveling screws set the accessory version. The 1/2″ accessories in the JMI range fit the standard-duty bars rather than this set.
• Weight as shipped is 34 lb. The frame arrives welded, in one carton.
• Availability. JMI builds this set to order and it moves in and out of stock; we can give you a current lead time before you order.

Frequently Asked Questions

Is it difficult to set up?

The frame arrives welded. Setup is a matter of choosing the width setting that suits the pier and the route, seating the pier base on the frame, and running the 5/8″ leveling screws down once the rig is parked. Nothing on the pier is drilled or modified.

Which Astro-Physics piers does it fit?

JMI lists the 6″, 8″ and 10″ Astro-Physics pier mounts, which covers piers used under the AP 400, 600, 800, 900 and 1200 mounts.

How is it different from a Universal Wheeley Bar?

The Universal bars capture three tripod feet in cups and adjust across a tip-to-tip span. This set is sized to the fixed base of an AP pier and is built heavier for the same 300 lb rating, on the HD Medium footprint.

Does polar alignment survive the trip?

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

What surfaces does it roll on?

The 5″ polyurethane wheels handle concrete, asphalt, pavers and cracked driveways, which is the ground a loaded pier is usually moved across.

Bottom Line

In short: a 300 lb welded steel Wheeley Bar set sized to Astro-Physics 6″, 8″ and 10″ pier mounts, on 5″ locking polyurethane wheels and 5/8″ leveling screws, with three width settings from 29″ to 47″, so a complete AP pier rig rolls out and rolls back in one piece. Made in the USA, 34 lb as shipped.