Wheel base measurements

UK PROFESSIONAL DRIVERS FORUMS OWNER AND FLEET OPERATORS FORUM (INTERACTIVE)
1

When the wheel base is quoted on a three or four axle rigid, which axles are the measurements between?

For example, on a four axle, is it between the first and last axles, or axles 2 and 3?

Likewise, for a three axle, is it between the first and second or first and third?

Thanks.

2

The total wheelbase is the distance between the centres of the front and rear wheels, regardless of how many axles there may be in between.

Regards,
Nick

3

My assumption (and it is only that, I’m not claiming to be right…) is that on a 3 or 4 axle double drive rigid it would be from the 1st axle to the centreline of the two drive axles. If it was a 4 axle rigid where the 4th axle was a steer axle it would be from the 1st steer axle to the drive axle. Those measurements are what I would call the effective wheelbase as far as turning circle calculations are concerned, the convention for what wheelbase to quote might differ though.

Paul

4

repton:
My assumption (and it is only that, I’m not claiming to be right…) is that on a 3 or 4 axle double drive rigid it would be from the 1st axle to the centreline of the two drive axles. If it was a 4 axle rigid where the 4th axle was a steer axle it would be from the 1st steer axle to the drive axle. Those measurements are what I would call the effective wheelbase as far as turning circle calculations are concerned, the convention for what wheelbase to quote might differ though.

Paul

^ this

for the purposes of calculating rear overhang on a 3 axle rigid it’s also from centre of the front axle to a point mid way between the two rear axles ( assuming it’s not a Chinese 6 :wink: )

for the purposes of specing a wheelbase for a new rear lift 6x2 rigid it’s the measurement from the center of the steer axle to the centre of the drive axle

5

Thanks guys.