10″ Pneumatic Wheel Upgrade · 1/2″ Leveling Screws
Roll your loaded Wheeley Bar over grass, gravel, dirt, or rough pavement — six 10″ all-terrain pneumatic wheels replace the standard 2⅜″ casters.
The factory 2⅜″ hard-rubber casters that ship with the JMI Wheeley Bar work great on smooth driveways and garage floors, but they fight you on grass, gravel, mulch, sand, or anywhere the surface isn't paved. The 10″ Pneumatic Large Wheel Upgrade replaces those small casters with six 10″ all-terrain pneumatic wheels — the same tire profile you'd find on a serious garden cart — plus a tow handle for easy pulling. Once installed, your bar rolls over almost anything without skidding, sinking, or yanking your shoulder.
This is the 1/2″ version — sized for the Standard Medium Wheeley Bar and older HD Medium / HD Large model years that use 1/2″ leveling screws. The tow handle bracket included in this upgrade is sized for the 1/2″ frame. For current HD bars with 5/8″ leveling screws, see the 5/8″ version. Made in the USA by JMI, part of the CXB Astro family.
Purchase-time upgrade pricing. This $364 price assumes JMI is swapping the factory casters for the 10″ wheels before shipping your new Wheeley Bar — you pay the difference between the casters and the wheels, not the full retail price of the wheels. For an already-owned bar, see "Upgrading an existing bar?" below.
Specifications
What's included
Six (6) 10″ all-terrain pneumatic wheels (2 front swivel casters + 4 rear in dual-inboard pairs) · tow handle assembly with 1/2″-compatible bracket · all mounting hardware
Replaces
Factory 2⅜″ hard-rubber casters and the bar's standard wheel hardware
Wheel configuration
Dual inboard rear wheels (4 wheels in pairs) keep the bar's track width narrow despite the larger wheel diameter · 2 front swivel casters for maneuverability
Ride height change
Raises the mounted scope approximately 3¼″ off the ground vs. the factory caster setup
Designed for
JMI Wheeley Bars with 1/2″ leveling screws — Standard Medium and older HD Medium / HD Large model years
Best for
Grass, gravel, mulch, sand, rough pavement, lawn-to-driveway transitions — anywhere the factory casters would skid, stick, or sink
Tow handle status
Tow handle is included with this upgrade — no need to add the standalone 1/2″ Tow Handle separately
NOT compatible with
Current HD Wheeley Bars with 5/8″ leveling screws (different tow handle bracket) · Triangle Style · Sky Trekker series
Made in
USA by JMI · part of the CXB Astro family
Why Pneumatic 10″ Wheels?
The biggest practical difference between rolling on 2⅜″ casters and 10″ pneumatic wheels is whether the wheel cuts into the surface or rides over it. A small caster's contact patch is barely larger than a quarter — it digs in on grass, jams in gravel, and stops dead on the first stick or rock. A 10″ pneumatic wheel has a 2–3 inch contact patch with give from the air pressure — it rolls over what a caster catches on. The cumulative effect: less stalling, less yanking, less risk to your mount when you hit something you didn't see in the dark.
Upgrading an Existing Bar?
This SKU is priced for purchase-time installation by JMI. If you've already taken delivery of your Wheeley Bar and want to add the 10″ wheels later, an aftermarket path exists: JMI can sell you the wheels, bracket, and tow handle separately for self-installation — but only if your current wheels are bolt-attached (current manufacturing method). Very old bars with rivet-attached wheels can't be retrofitted. Email support@cxbastro.com with your bar's age and a photo of the wheel mount; we'll confirm whether you qualify and quote aftermarket pricing. (Aftermarket pricing is higher than $364 because there's no caster "trade-in," and JMI doesn't accept returns of used factory casters.)
5/8″ Leveling Screws Instead?
If your Wheeley Bar uses 5/8″ leveling screws — current HD Medium, HD Large, or HD Shorty — order the 5/8″ 10″ Pneumatic Wheel Upgrade instead. Same price ($364), same six wheels and tow handle, but with a tow handle bracket sized for the 5/8″ frame.
Frequently Asked Questions
How do I know if my Wheeley Bar has 1/2″ or 5/8″ leveling screws?
Pull one leveling screw out and measure the thread diameter with calipers or a ruler. 1/2″ is the older standard — Standard Medium bars and earlier HD Medium / HD Large model years. 5/8″ is the current HD standard — newer HD Medium, HD Large, and HD Shorty bars. If still unsure, email support@cxbastro.com with a photo of your bar.
What does "purchase-time upgrade" mean? Can I order this for a bar I already own?
The $364 price assumes JMI is swapping the factory casters for the 10″ wheels before shipping your new bar — the small casters are essentially "traded in" toward the larger wheels. For already-owned bars, JMI can sell the wheels, bracket, and tow handle as an aftermarket kit for self-install (bolt-attached wheels only — very old riveted bars can't be retrofitted). Email support@cxbastro.com for aftermarket pricing and to confirm your bar's eligibility.
Why six wheels instead of four?
The rear axle uses a dual inboard wheel design — two pairs of wheels on the rear instead of one wheel per side. That keeps overall track width narrow (so the bar still fits through doors and tight setup spots) while doubling the rear contact patch for stability under a heavy mount. Front gets two single swivel casters. Total: 6 pneumatic wheels.
Is the tow handle included with this upgrade?
Yes — a tow handle is included as part of the 10″ wheel upgrade. You do not need to add the standalone 1/2″ Tow Handle product when you order this upgrade. If you want a longer handle (12″ longer than standard), the Tow Handle XL upgrade still applies and is sold separately.
How much higher does the bar sit with 10″ wheels?
About 3¼″ higher than with the factory 2⅜″ casters. Worth knowing if you're sensitive to total observing height — most observers find the extra height welcome (fewer back-bends at the eyepiece), but if you're already at the upper end of your scope's comfortable eyepiece reach, factor it in.
Will the 10″ wheels survive sharp gravel and broken pavement?
Yes — they're all-terrain pneumatic tires built for garden carts, wheelbarrows, and similar duty cycles. The tubed design can take occasional punctures (carry a patch kit if you'll observe on sharp gravel regularly), but the rolling resistance is dramatically better than any solid wheel of comparable size.
Ordering a fresh Wheeley Bar?
Add the 10″ Pneumatic upgrade and let JMI install before shipping. Already own one? Email support for aftermarket pricing.
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