Flatbed or service body?
Short answer: a flatbed is an open deck for hauling and loading from any side; a service (mechanic) body puts locking compartments and equipment — cranes, air compressors, power systems — on the truck. Both are sized to your chassis by cab-to-axle (CA).
Compare
| Flatbed / hauler | Service & mechanic body | |
|---|---|---|
| Best for | Hauling materials, pallets, equipment; gooseneck/5th-wheel towing | Carrying tools and parts securely; field repair with crane, air and power |
| Examples we install | CM RD, SK, HS/TM/ER haulers, PL platforms | Stellar TMAX mechanic bodies; CM, DuraMag and Royal service bodies |
| Fitment | CM sizes beds by length, width, CA and runner (see the Outfitter Guide) | Stellar lists CA and GVWR ranges per TMAX model (see the TMAX brochure) |
| Add-ons | Hitches (CURT gooseneck/5th-wheel options on CM beds), toolboxes, headache racks, lighting | Cranes, air compressors, welders/generators, ladder racks, lighting |
Fitment in one minute
Measure from the back of the cab to the centre of the rear axle — that is CA. Per the CM Outfitter Guide, a pickup with a long bed or dually typically has a 56–58″ CA and takes an 8′6″ bed; cab & chassis trucks with a 60″ CA take a 9′4″ bed and 84″ CA take 11′4″. See the fitment diagram and the CM guide.
For mechanic bodies, Stellar publishes CA and GVWR ranges by model in its TMAX brochure — for example TMAX 1 for 60–84″ CA and 16,000–19,500 lb GVWR chassis. Stellar TMAX brochure (PDF).
Questions to answer before you quote
- What do you carry every day — open loads or tools and parts that must lock up?
- Do you need to lift (crane), run air tools (compressor) or weld on site?
- Will you tow? With what hitch?
- Chassis: make, year, cab, CA and GVWR (door-jamb sticker). Check payload with our payload calculator.
Sources: CM Truck Beds Outfitter Guide (cmtruckbeds.com/outfitter-guide); Stellar TMAX Series brochure (stellarindustries.com). VSI confirms fitment on every quote.