I made a couple of additional
measurements motivated by a reader’s comment. Last time in “Chassis supports and door bars – project ready” I used car’s own weight to bend the front and
rear downwards. This time I put weight on the door sill and measured the
bending that way.
Here are the results:
Weight 70 kg, without
door bar. Left: 0,35 mm. Right 0,35 mm.
Weight 70 kg, with
door bar: Left: 0,27 mm. Right 0,27 mm.
Weight 100 kg,
without door bar. Left: 0,51 mm. Right 0,49 mm.
Weight 100 kg, with
door bar: Left: 0,39 mm. Right 0,40 mm.
Conclusion is that
door bars reduce bending 18-23 % when measured with 70-100 kg weight. Sounds
nice, doesn’t it!
Seriously, deflection
with 100 kg is less than half millimeter measured from the height of windscreen
frame. Bars seem to work and they give some extra stiffness to old car’s
chassis.
