[TR] TR3 rear spring specification

[Randall]

> I was also told that most if not all makers of 
> reproduction TR springs just made the TR4 springs because it 
> was cheaper 
> make one set than two sets with different spring rates.

That's certainly a very interesting story, even if it is an old husband's tale.

Anyone have the TR4 spring specs handy?  They don't seem to be in the workshop manual.

I'm not quite done with my experiments yet, but so far both original springs that I have tested are quite close to the TR3 manual
but just a bit stiffer (about 8%, lending credence to Jonmac's story).  However, the new spring checks almost 75% stiffer than the
spec!  (222 lb/in rather than the spec 128)  It seems unlikely to me that the TR4 weighs that much more than a TR3, but maybe the
standard springs were stiffer (relative to the TR3) for more reasons than just body weight.

-- Randall