The question I would ask before the shipping quote
Imagine you have found a used tractor at a price you like. The cab looks clean in the photos. Your semi-trailer is already working, so it is tempting to ask for freight and move on.
I would pause here: will this particular tractor work with the trailer you already own, on the route you actually run? The badge on the cab and the horsepower figure will not answer that. Put the details of both vehicles on one sheet before paying a deposit.
Will the fifth wheel lock onto your kingpin?
Ask for a clear photo of the tractor fifth-wheel plate, its label and locking mechanism. Send the supplier your trailer kingpin specification and current photos. The type, size and wear condition of both parts matter.
JOST provides different wear gauges for 2-inch and 3½-inch kingpins and couplings. It also describes its size adapter as suitable only for internal transport. “It looks as if it will fit” is no substitute for checking the fitted components with a qualified technician.
Will the trailer sit properly behind the cab?
Compare the tractor fifth-wheel height in its intended operating condition with your trailer coupling height. Then look beyond the numbers: will the trailer sit correctly, and is there space between its front and the cab when turning?
Tyres, suspension setting and fifth-wheel mounting can all affect the practical fit. Ask for measured dimensions of the offered vehicle rather than relying on a generic brochure.
What happens when the trailer is loaded?
Tell the supplier what you carry and how heavy the full combination will be. Share the trailer axle arrangement and expected load distribution; ask for the proposed tractor axle and fifth-wheel ratings. Horsepower alone cannot establish the permissible load.
Registration, axle and route limits vary by destination. Have the operator or a qualified local specialist confirm what applies to your actual combination before committing.
Can the two vehicles brake and communicate together?
Exchange photos and specifications for the air-line couplings, electrical sockets and any ABS or EBS equipment. Matching plugs do not prove that the braking functions will work together. Agree on a coupled functional test if both vehicles can be brought together.
UN Regulation No. 13 covers heavy-vehicle braking, but the rules applicable to your country and vehicle still need local confirmation.
What has the supplier confirmed in writing?
The quotation should identify the exact tractor and state its relevant coupling specification and height, axle configuration, tyres, brake and electrical interfaces, plus any preparation included. Mark anything still awaiting measurement or a coupled test as pending.
A useful first message is: “I have a [trailer type] with a [kingpin size], [coupling height], [brake system] and [expected loaded weight]. It will work in [country] on [route]. Which used tractor would you suggest, and what still needs checking before I commit?”
At RUICHI, we can discuss used HOWO and SHACMAN tractors against that information and provide photos, configuration details and a quotation for a selected vehicle. Final fit, condition, preparation and delivery terms should be confirmed for that specific unit in writing.