The four measurements we ask for before any chair ships
Nine out of ten fitment problems come down to a number nobody wrote down. Here is exactly what to measure on a Class A or Class C, where to measure from, and what a wrong reading costs you in freight.
Every week someone calls because a chair arrived and the bolt holes do not line up. Almost always the chair is right and the base is wrong — and the base was specified from memory rather than a tape measure. Four numbers prevent it.
1. Base height, floor to seat pan
Measure from the finished floor to the underside of the seat pan with the chair in its normal driving position. Class A coaches typically land on a 7″ or 10″ swivel base; Class C chassis use a bracket that is specific to the year and make. Half an inch out and your knees sit under the steering wheel.
If you only take one number, take this one. Height decides comfort, clearance and whether the chair swivels past the dash.
2. Bolt pattern, centre to centre
Pull the four bolts holding the existing base to the floor and measure centre to centre, front to back and side to side. Write both numbers down in that order — plenty of patterns are close but not square, and a 11″ × 13″ is a different part to a 13″ × 11″.
| Ford F-53, 2014+ | 11″ × 13″ | 7″ swivel |
| Freightliner XC | 13″ × 13″ | 10″ swivel |
| Chevy 4500, Class C | 12″ × 14″ | Chassis bracket |
| Sprinter 2500, 2019+ | 10.5″ × 12″ | Sprinter front base |
3. Clearance to the dash and door
With the seat fully forward, measure from the front edge of the seat pan to the dash. Then swing the door open and measure the gap at the widest point of the chair. Wide chairs like the De Leon need roughly two extra inches of swing clearance compared with a Monument.
4. Belt anchor position
If your coach carries the belt in the chair rather than the B-pillar, you need an IS model and the anchor points have to match. Photograph the existing anchor and send it with your measurements — it takes us thirty seconds to confirm, and it is the single most expensive thing to get wrong.
What happens if the numbers are off
A chair that does not fit goes back on a pallet. Freight each way runs $180 to $260, and the replacement joins the build queue behind whatever is in it that week. Ten minutes with a tape measure saves both.
When you have the four numbers, call 800-454-1801 or put them in the notes field at checkout. We check every order against them before it is released to the factory.
Send a photo of the base and we will tell you exactly what it is.
