I have 4 Nightrider 36er tires, all of which have become flattened at the crown, making them all very sensitive to road camber, compared to when they were new. Adjusting PSI doesn’t help much because the contact patch remains flattened.
I experimented with different ways to restore the round profile, and found that the most effective solution was the “Tread doctor tire groover.” It heats up a 5/8" wide sharp carbide cutting head and literally slices through the rubber like butter.
I finished the job and it seems to have worked great and now the tire is probably rounder than it was when new. A quick test ride on a sloped road and the camber pull is completely gone! FYI, I worked in small sections, one side at a time, starting at the very beginning of the first transition knobs next to the center diamond, and slicing progressive deeper towards the outermost
outermost knobs.
Really depends on several factors, like rider weight, psi, road type, etc. The lower the psi, the greater the contact patch, which also will wear down a wider patch of tread. I weigh about 155lbs and usually ride with around 50-55 psi, which focuses most of the wear on the center tread, which also can accelerate wear in that area, leading to the flattened profile. And the flatter the profile becomes, the squarer it becomes under rider weight, as more and more side and outer treads come in contact with the road, causing camber pull on even mildly sloped roads.
Too bad you were not closer to me, I would have traded the flattened Nigthrider tire for new tire. I went from a worn out Nightrider to a new one and did not like it at all. I ended up switching to a King George. I really like how the worn Nightrider and King George can make nice smooth turns just by leaning into the turn. They are also pretty much self balancing in the left/right direction. I don’t often ride on cambered roads.
I’ve often wondered if there was such a tool to do this but never researched it. Hmm, could it be used to “open up” the tread of the NR - like removing every other “block” - to turn it into a knobby tire for off-road? And that would certainly lighten it up. Rolling resistance be damned.
