Moto Grand Prix
Main Motorcycle: 1973 Triumph TR7RV
Join Date: Oct 2013
Location: Pleasant Hill, CA USA
Other Motorcycle: 1964 Triumph Mountain Cub
Hi All, Interesting how the modern K70 wears. In the 70s they lasted much longer front or rear. The front had a propensity to cup the tread off each side of center row & the center not so much.
Now with modern ones the sides of front cup very quickly & the center cups quickly as well. But the sides are much more prone to cupping now that then. I've experimented with tire pressure. As expected the cupping is worse if you run pressures too low.
The rear has always worn in the center, but now it's much worse.
I had no idea of how different the modern k70 was until I got some. With the old spec the tire felt very squirmy, especially on deep rain grooves.
I kept my original tires from when bike was new. The carcass on the modern tire is smaller overall diameter, but mostly similar in width.
I can get about 15k miles on front k70 now until sides are so cupped the handling is very compromised. They get noisy off a straight line in only about 1000 miles.
The rear tire only lasts about 7-9000 miles until center tread is bald. I corner gently, never spin rear wheel & try to avoid skidding. Some get much less miles than I do.
Some don't like the cornering or wet ability of the modern k70, but to me it's better than the originals seemed in the 70s. I've paid attention to how they perform on the club rides. Some guys lean the bikes so far & ride the curves so fast. Keeping up with modern tires. So I don't know what to think.
I like the looks of them so I use them.
I'm 160# ready to ride. I've been running 30 front 31 rear. If 2 up I do 33 rear. I used to run 28 rear, didn't seem to make the center of tire last much longer though. For sure to me the bike handles better with the higher pressure. Odd as it may seem it might ride a little smoother with the higher pressure also. I did some experiments on that. Looking at front tire going over bumps it didn't look like tire was compressing much more with the lower pressure, so not even close to a rim pinch.
I still find the whole tire issue interesting & puzzling.