If you're getting arse trouble after only 8 miles then you don't have a suitable saddle. Fix that first and only then worr about special shorts. I remember in my youth being in absolute agony 30 miles into a 45 mile ride. Cured by buying a brooks b17 saddle. It must have been at least 20 years later i bothered with special shorts - which are "a good thing" but if you're in pain after 8 miles are certainky not the answer. Note: Brooks b17 and team pro leather saddles suit me very well from first day - no breaking in and no exotic potions - but may be agony for someone else. Saddle first !
Ah. I've accidently misled everyone. My arse soreness and numbness was brought on by a 14 miles ride yesterday.
The 8 miles one was to make more adjustments. Both backside and nuts were fine today. But it was only 8 miles
Apologies