Mike's Renntec Testing

[simi_ed]

This whole discussion really needs it's own topic, so I started one. 

This discussion of brakes and crashes seems to mesh very well with the recent discussion of OEM 4 piston calipers vs. Blue/Gold Dots.  Mike's issue partially arose from lack of discerning from heavy braking to wheel lock.  My contention is that the extreme of braking (where Mike obviously was) ANY lever effort not generating braking force is not just wasted, but potentially dangerous.  In this case the extra pressure may go to caliper flex, or braking.  If you can't tell what's happening that's bad!  Comparatively, blue dots are rigid and flex is NOT present.  Better lever feel, better and more controllable braking; no crash (perhaps).  Anybody have a differing POV?

Mike, If you're not running a 3.5" wide front wheel, YOU SHOULD!  I noticed a large improvment in braking ability when I upgraded.  More rubber on the ground, less time on the ground.

Firstly, brakes did cause the accident, he locked the front wheel up on a near vertical bike and it washed out from under him. The fact the forks fully compressed under brakes also suggests the tyre had tons of grip, that is, no sand.

Noel, I know. I need to work on my braking. But I don't know where the "nearly vertical" comment is coming from.  If I were 5-10 degrees from vertical, okay. But for the perspective impaired I'll attache this, which is a few frames before I grabbed the brakes.





In the slow motion you can see the way all of the forces interact as the tire grips the road. The front end dives dramatically because the for springs are really light, and the racetech valves I'm running go into bypass when they're loaded like that. You can also see the way the bike wants to "stand up" and how this tendency immediately disappears when the tire begins to slide and the bike falls back over. 

Guys, relax, you're not hurting my feelings over the braking thing. I know I screwed up. I have been and will continue practicing with the brakes to get to that second nature point. It's just that I am so dang nervous about locking them even in a controlled situation when the bike is upright.

I think an important point that most of you know, but don't necessarily understand, is that you have a "traction budget" for every tire on the vehicle. (It applies to cars too) A tire only has so much traction to offer you. This available traction changes continuously due to factors such as road surface, tire temperature, and weight being carried. The temperature and road surface are the less dynamic factors for my level of riding. The bigger one that played in this case was the loading. Your available traction goes up, to a point, when you put more weight on your contact patch. When you grab your brakes in a panic you can clearly see that there is a DRAMATIC shift of weight to the front wheel. This is fine when you are upright because the extra load is normal to the road surface and you are getting the maximum traction benefit. When you are not perfectly upright though this means you are asking your tire to absorb a cornering force as well as a braking force. Since the load is not normal to the road surface you get some increase in traction, but the lateral component adds to the traction requirement. This added to the fact that your braking is also using available traction means that you're going to go over budget pretty quick...

But still, understanding this and actually putting it into practice aren't even related. All you need to do is what has already been mentioned. Practice practice practice....