A car turntable looks like a simple disc, and the two numbers that decide everything are the diameter and the load capacity. Get either wrong and the vehicle either overhangs the edge or the drive struggles. This guide works through how to size both, using projects we have actually built.
What the diameter has to cover
The diameter is set by the longest vehicle that has to turn, plus the clearance you want at each end. A turntable that is exactly as long as the car looks tight and leaves no room for a driver to open a door or for a wheel to sit near the edge, so most installations allow a margin of 200 to 500 mm at each end.
The vehicles we have built for range from a small passenger car on a 5.5 m disc to commercial vehicles on a 16 m platform, and the same rule applies at every size.
Capacity is about axle load, not just kerb weight
Capacity is the total weight the turntable is rated to carry. A car’s kerb weight is the starting point, but what matters more is how that weight is distributed: a turntable carrying a vehicle that sits on two axles close together sees a very different load from one carrying the same weight spread over a long wheelbase. Tell your supplier the vehicle, not just a tonnage.
Three real projects, three different sizes
| Project | Market | Configuration |
|---|---|---|
| Showroom and garage turntable | Namibia | 5.5 m diameter, 420 mm overall height, 2.5 t load, 1 to 2 rpm, RV63 reduction drive, Harbin bearings, pin gear transmission, deck and roundness within plus or minus 10 mm |
| Heavier vehicle turntable | Tanzania | 6 m diameter, 500 mm height, 6 t load, 380 to 400 V three phase, 120 x 60 x 5 mm frame |
| Large commercial turntable | Bangladesh | 30 t load, 16 m diameter, platform 12 to 16 m to take vehicles up to 14 m, flush installation on a 300 x 100 mm pit frame, 2.0 kW motor, large slewing bearing, built to a tender specification |
| Compact turntable, imperial market | Bangladesh | 2 t load, 8 ft height, 12 ft diameter, sized to imperial units for the customer’s drawings |
The pattern is consistent: the diameter follows the vehicle length, the capacity follows the heaviest vehicle plus margin, and the drive system follows the duty cycle.
What goes into the specification
| Item | Typical specification |
|---|---|
| Outer diameter | 2.5 m to 16 m, set by the longest vehicle |
| Load capacity | 0.5 t to 30 t |
| Overall height | 420 to 500 mm, or flush with the floor in a pit |
| Rotation speed | 1 to 2 rpm, set during manufacturing |
| Drive | Pin gear transmission with RV63 reduction drive |
| Bearing | Large diameter slewing bearing, Harbin Bearing |
| Flatness and roundness | Within plus or minus 10 mm |
| Power supply | 380 to 400 V, 50 Hz, three phase; other voltages on request |
| Deck options | Steel plate as standard, aluminium alloy plate for display areas |
| Warranty | 12 months, excluding man-made faults |
Foundation, pit and finish
Most turntables are installed flush with the surrounding ground in a shallow pit, with the frame set in a recess. A typical arrangement uses a pit frame of around 300 x 100 mm for the ring, and the finished deck is set level with the surrounding surface so vehicles drive on without a ramp.
Two tolerances matter more than any other when the unit arrives: the flatness of the deck and the roundness of the disc, both normally held within plus or minus 10 mm. A turntable outside that tolerance will rock under a vehicle, which is felt immediately through the steering wheel.
The surface finish can be matched to the installation: standard steel plate, or an aluminium alloy deck where appearance matters, such as a showroom or a vehicle display area.
Transport and installation
Turntables ship as a compact package rather than a full disc. A 5.5 m unit travels in a case of roughly 3200 x 1250 x 2200 mm weighing about 2.5 t, and a 6 m unit in about 3 x 1.2 x 2.2 m weighing around 2 t. The disc is assembled on site, which is why the pit dimensions and the assembly sequence need to be agreed before the concrete is poured.
Frequently asked questions
How do I choose the diameter of a car turntable?
Measure the longest vehicle, add 200 to 500 mm at each end, and round up to the nearest standard size. In practice a passenger car fits a 5.5 m disc comfortably and a long-wheelbase commercial vehicle needs 6 m or more. For commercial vehicles and buses we build platforms up to 16 m.
What capacity do I need for a 2.5 tonne car?
A 2.5 t turntable is the standard choice for passenger cars and light vans, and it is the size we most often build for showrooms and domestic garages. If the turntable will also take delivery vehicles or loaded trailers, step up to a 6 t or larger unit rather than running the smaller one at its limit.
How is the turntable driven?
The units we build use a pin gear transmission with an RV63 reduction drive and a large diameter slewing bearing, turning at 1 to 2 rpm on a 380 to 400 V three phase supply. The speed is set during manufacturing, and a smooth stop is built in so a vehicle does not lurch when it reaches position.
Next step
Tell us the longest and heaviest vehicle the turntable has to take, whether it will be installed flush with the floor, and whether the location is indoors or outside. We will confirm the diameter, the capacity and the pit arrangement, and send a dimensioned drawing for approval. See our car turntable page for the full specification range.