The Hofmann MONTY 3850 is a truck tire changer built around an electro-hydraulic drive rather than the pneumatic systems used on car-and-light-truck machines. That single design choice is the reason this unit belongs in a commercial truck bay: hydraulic pressure — 160 bar at the chuck — delivers steady, controllable force at low speed instead of the sharp, on-off push of an air cylinder, and low-and-steady is what a 59" commercial tire needs when its bead is seized onto a steel rim.
It is a single-tower assist machine for commercial and agricultural service work: truck, bus, trailer and light earthmover assemblies, handled by one technician working from a control unit that rolls to the wheel rather than a fixed panel the technician has to walk back to.
Hydraulic drive, and what it changes at the bead
A pneumatic tire changer stores energy in compressed air, so its force arrives quickly and is difficult to modulate part-way through a stroke. A hydraulic circuit does not compress; the force you command is the force you get, and it holds there. On the MONTY 3850 that shows up in two places. The bead breaker roll works its way around the rim under continuous pressure rather than in bites, which is what keeps a stiff commercial sidewall from being levered against the flange. And the chuck turns at 7 rpm — a deliberately slow, high-torque rotation, not a productivity compromise. At that speed the technician can watch the bead move, stop, reposition the tool and start again, which is the difference between a clean demount and a damaged rim on a wheel that may be worth more than the tire on it.
An infinitely self-centring hydraulic chuck
The chuck is universal and self-centring across its whole range, which means it is not stepped into fixed positions — it clamps wherever the centre bore actually is, anywhere in a 14-26" (356-660mm) centre-bore range. In practice that covers the great majority of commercial steel and aluminium truck wheels without an adapter change, and it removes the most common source of run-out damage on this class of machine, which is a wheel clamped very slightly off-centre and then rotated under load.
The safety valve on the chuck
This is the feature worth understanding before you compare this machine with anything else. The chuck carries a safety valve that prevents accidental unclamping. A truck wheel and tire assembly on a hydraulic chuck is a large mass held by fluid pressure; a lost line, a knocked lever or a mis-keyed control on a machine without that interlock releases it. The valve means the clamp does not open because something upstream failed — it opens because the operator asked it to. On equipment this size that is a personnel-safety feature, not a convenience.
Mobile control unit and swing-arm tooling
The control unit is mobile and vertically adjustable. The technician positions the controls at a comfortable working height beside the wheel, sees the tool contact point directly, and makes fine adjustments while looking at the work instead of over a shoulder. The bead breaker roll and the mounting/demounting tool are both carried on the swing arm, so the two operations share one accurately positioned arm rather than needing the wheel to be re-set between them. Positioning of both the wheel and the tool is adjustable across a wide range, which is what lets one operator handle assemblies that would otherwise need a second pair of hands.
Will It Fit?
Three things to check before ordering.
Power. The MONTY 3850 runs on 208V, 1Ph, 60Hz. That is single-phase, so it does not require a three-phase service — but 208V single-phase is not a standard wall outlet either, and it is on the customer to have a suitably rated, correctly fused circuit run to the machine's location by a licensed electrician before delivery.
Floor. The unit weighs 1,212 lbs. and works loaded truck assemblies, so it wants a sound, level concrete floor. Have your own contractor confirm your slab is adequate for the installed weight plus the wheels you intend to handle.
Working space. Because the control unit is mobile and the arm swings, plan clear floor around the machine rather than just the footprint of the machine itself — the technician needs to walk the controls around the wheel, and a wheel up to 59" (1,500mm) in diameter has to be rolled in and out.
Perfect For
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Commercial truck and trailer service shops handling steel and aluminium drive, steer and trailer wheels daily.
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Fleet maintenance operations — municipal, refuse, utility, agricultural — where wheels come off in-house rather than going to a vendor.
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Bus and RV service centres where the assemblies are heavy and the wheels are frequently cosmetic.
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Tire dealers adding a commercial bay to a passenger-car operation.
What's in the Box
The machine is supplied with the items its own feature list names: the electro-hydraulic drive unit, the mobile control unit, the self-centring universal hydraulic chuck, and the bead breaker roll and mounting/demounting tool fitted on the swing arm. Anything beyond that — additional adapters, specialist tooling, consumables — is not listed as included, so ask us before you assume it is in the crate.
Key Specifications
| Clamping centre bore range |
14-26" (356-660mm) |
| Maximum wheel diameter |
59" (1,500mm) |
| Chuck speed |
7 rpm |
| Hydraulic pressure |
160 bar |
| Power supply |
208V / 1Ph / 60Hz |
| Machine weight |
1,212 lbs. |
| Style |
Truck |
| Assist type |
Single tower assist |
One figure we will not pick for you
Our two sources for maximum wheel width disagree. The specification table published on this page gives 27.5" (698mm); the product's own spec field gives 28". Half an inch rarely decides a purchase, but if you are buying this machine specifically for a wide-base or super-single wheel that sits near the limit, contact us and we will confirm the figure with Hofmann against your wheel before you order rather than guess at it here.
Certification and compliance, honestly
The product data we hold for the MONTY 3850 does not record a third-party safety listing, and we will not imply one it does not claim. A manufacturer's own declaration of conformity is a different document from an independent, third-party listing carried out by an accredited body, and the two are not interchangeable. If your insurer, your fleet policy, a franchise agreement or your local authority having jurisdiction requires a specific listing for shop equipment, establish exactly what they require and ask us to confirm this machine's documentation against it before you buy.
Shipping and delivery
This is freight equipment, shipped to the lower 48 states. Delivery arrangements for Hofmann machines are set out in the Pick Up and Delivery section further down this page, and they differ from our general freight terms — read that section, and if anything there does not match what you see at checkout, confirm it with us before ordering. Whatever the arrangement, one rule always applies: inspect the shipment before you sign. Walk around the crate, look for punctures, crushed corners, shifted load or damaged banding, and note anything you find on the bill of lading at the time of delivery. A signed clean BOL is your statement that the equipment arrived undamaged, and it is very difficult to unwind afterwards.
Warranty
Warranty coverage is handled under our published warranty claims process; we have not stated a term here because the product data we hold does not specify one, and we would rather send you to the actual policy than quote a length we cannot verify. One practical warning that applies to every hydraulic machine we sell: do not disassemble a suspect component before you open a claim. Photograph the fault in place, record the serial number, and contact us first. A unit that has already been opened up is frequently outside the terms of any claim, however genuine the original fault was.
