Fender measurements

[kenafp]

Just curious as to how much clearance should I have with the fender, above the tire.
Is there a way to calculate or measure it?

[tony.latham]

Just curious as to how much clearance should I have with the fender, above the tire.
Is there a way to calculate or measure it?

If there's a way to calulate it, I'm not in the loop. With a Dexter Torflex axle, I make sure there's 4" between the tire and the fender after the teardrop is on the the chassis. That measurement should be at about the 2 o'clock positon since the axle arm swings up and back a bit. Dunno about the spring axles.

I'm one of the oddballs that builds the teardrop cabin on a dolly and then loads it on the chassis. Thus the comment about what the measurement should be after the chassis is loaded.



T

[KCStudly]

For a leaf spring axle, measure the distance between the frame and the closest point where the axle (in a "spring under" configuration) or spring pack (in a "spring over" configuration) will hit. Then add about an inch to 1-1/2 inches for tire deflection and axle flex or tilt (i.e. one wheel lifting while the other drops out), more if you are running bump stops that may compress some.

Same for side wall clearance, about 1 to 1-1/2 inches is a good minimum to shoot for, IMO.

Some may argue that a trailer is a tripod and you can disregard axle tilt, but I would argue that if, at speed, you hit a pothole on one side and simultaneously hit a bump on the other, the kinetic energy of the mass of the cabin will tend to keep the trailer moving level while the axle reacts underneath it. Otherwise, why have springs at all? And if you don't believe that this happens regularly in normal driving, then you have never driven in New England (otherwise known as pothole and frost heave country).