Hi Sancho
The SKF is the better bearing. I have sold probably what? 200 sets without a problem but I can't stop people from blaming the bearing.
BUT, there is one thing you should note, KTM have STOPPED the NTN bearing and carried on with the sale of SKF.
this is tremendous news because despite the weight of vile comments against me I offer those two absolutely compelling facts;
KTM dropped the bearing
200 pairs sold no problems
essentially Sancho, the ends of the rollers have two dfifferent shapes. the SKF are square ended. 90 degrees. the NTN rise to the middle of the end ever so slightly - not much.
and now I offer you a simple scenario; your mother calls you and says; "Sancho, get over here and knock the front wall down, I will be putting up a wooden fence"
"OK, Mum"
you go over to Mum's with a 10LB hammer.
Sancho where would you first strike to bring down that wall? in the middle/top or on the very bottom brick? will hitting the very bottom brick bring down the wall or would hitting the middle brick?
well, the main bearing inner race has a wall at the end - a shoulder. I don't want to break that wall but the crankshaft will wander and the rollers will keep hitting it, infact they will smash into it a lot. so is it best that the roller contacts the inner race at the bottom or half way up?
Below is a photo of spalling on a customers inner race but you get a perfect view of the shoulder on the inner race that breaks off.
the other two photos are of the inside of a crankshaft. there is a curved dark area like the 'spike' on a heart beat monitor. this is where the pin leaves the inside of the crank. the carnk is very flexible. this means the rollers are always hitting the shoulder (the wall).
Taffy
