Front wheel feels like its hopping during hard braking

[bartman5impson]

braking video

I've been practicing hard braking and have experienced what feels like the front wheel hopping because the whole front end of the bike pulses up and down. In the video I am only using the front brake and I'm applying it progressively. I don't feel like I'm braking as hard as I could be and as you can see I let off the brakes because it feels like my front wheel is going to lock up.  I've locked up the front wheel a couple of times before and it's surprised me because I'd expect the rear wheel to lift first.

Is there something wrong with my technique or could it be my bike?

Edited October 30, 2020 by bartman5impson

[xor_bot]

It sounds similar to what I experienced. In my case the front was very sketchy under braking (it almost felt like ABS was kicking in when I wasn't even braking that hard), and the feeling while cornering was off too. It was like the front had a mind of its own when the bike starts to lean over. It's a 2014 model and had 14500km on the clock when I got it. Anyway I took off the forks, replaced the oil with Bel Ray 15W, lowered the front by 8mm, and cut the spacer by 8mm (basically this video: https://www.youtube.com/watch?v=X-uiiksWsOs), and in the process also realigned the front. The bike was totally different after this. Much more predictable under braking and in cornering. Granted, I did multiple things, and perhaps it's only one of these that made a significant difference. Assuming your tires and brake system is all good, I'd recommend checking the alignment first as that's a simple thing to do.

[mossrider]

Threshold braking, done properly, can give exactly the results you're experiencing. Meaning this could very well be normal. There are; however, a couple other possibilities.  

First, this may be entirely the tires natural behavior at threshold braking on that particular road surface under those particular conditions. As that tire struggles to maintain grip it could certainly give that feel of grabbing, searching, sliding, oscillation.

Or, your pads and rotors may not be in optimum condition. They could be dirty, worn, or just the tiniest bit warped. Any of these can create a feeling of grabbiness or pulsating if the rotational pressure is not constant. 

Or, in extreme conditions, this could also be caused by brake pads off gassing during threshold braking. This can force the pads ever so slightly off the rotor. All brake pads will create gas/dust as they wear under use. This material is created and can be trapped between the pad and rotor and can prevent proper brake operation during extreme use. 

Or, I've seen loose steering head bearings cause a jack hammer effect during hard braking as the forks/triples hammer back and forth during threshold braking.

Either way, your braking technique looks solid. When done rapidly and progressively as you were doing, your rear wheel will not necessarily come up very easily.