The haynes chassis design

[eSteve]

kev87,

I believe the book is correct.

The length of the back edge of BR10 (i.e. the length given in the cutting list on page 161) can be calculated from Fig 4.2 (on page 34) as follows, assuming 25 mm RHS is being used rather that 1" (25.4) not that it makes much difference:

Width of rail BR3 measured with respect to the centre line of the car and allowing for its angle (10 deg), is:

25 / cos 10 = 25.4 mm (it's wider than the 'stock' size since it is at an angle)

Take the twice width of the rail (25.4 calculated aboved) to account for BR4 and BR3 from the width of the chassis at BR10 given in fig 4.2:

924 - (2 * 25.4) = 873.4 mm This is the width ot the front of BR10.

So to calculate the width of the rear of BR10, since its ends are chamfered at 10 degs.:

873.4 + ( 2 * ( 25 * tan 10 ) ) = 882.2 mm

Cutting diagram on page 161 says 882 mm so QED.

Hope that helps (just remember S = O/H, C = A/H, T = O/A from your school trogonometry )

eSteve.