Hi All,
Keep in mind that the low tire pressure presented in the original Healey manuals was for Cross Ply Tires of the day … a far cry from todays lower profile radials belted radials. As you may note, I said lower profile since my original equipped Dunlop Road Speed RS5s had a higher side wall and came on 4" wide 60 spoke wheels. This combination called a tire pressure of (if I remember correctly) Front 21lbs, Rear 25lbs.
So, when considering the tire pressure you will be using, the first consideration is what wheel and tire you have mounted on your car. Todays tires are stiffer, wider, with less height and are mounted on wider wheels with more spokes. With this in mind, does it make sense to use as little air pressure as recommended for original wheels and tires or up the pressure to what is closer to that more commonly found on today's cars (i.e. Front 24-26 lbs., Rear 29-32 lbs.)? Also, keep in mind that with lower sidewall height, pre BJ8 Phase 2 models have little ground clearance to begin with and reducing tire pressure only diminishes this scarce commodity even further with increased tire flex. Additionally, tire flex also diminishes the tread stiffening function of a modern tires belt and, therefore, the tire's road adherence.
So, is it a good thing to lower the tire pressure to pre-modern tire levels? What is the real benefit derived? Since I can't answer these questions, I have no recommendations.
Just my thoughts,
Ray(64BJ8P1)