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Dirtbike + side street intersection = rear brake lockup

Posted: Thu Jun 29, 2006 4:30 pm
by Shorts
Well, I took my little 50cc midirtbike down the road to get the cobwebs out. It is a neighborhood street, 30-40kph speed limit.

Before I get the disapproving "you shouldn't have a dirtbike on street", I know (got a buyer coming in an hour, I wanted it warmed up). That lashing aside, please read on....

The bike is a little single speed auto, right brake is rear, left is front. I'm cruising along at 25kph, hugging the shoulder as per 50cc street rules. Passing a wooded area I'm coming up to the dirt drive that leads into that lot. Both areas of view at that road are blcked by overgrowth. Of course, you can all see it coming, a car pulls out from the dirt road and sticks his damn car out 1/2way into the street so he can 'see around the corner'. Anyhow, he sees me after he's in the way, but stops. By this point I have let off the throttle and grabbed the right front brake and squeezed. The rear locks and skids, which I control fine, then I let off the brake when I was slowed down enough to swerve around. As I pass in front of him, he gets a look, and knows it too as he returns the stare.

Anyhow, I'm both troubled and relieved at my response.

Relieved:
1) I handled the bike like it was nothing when the rear locked up. I remember when I first got the bike I intentionally practiced locking the rear to learn how the bike would act (since I only use the rear brake on this bike). So, that planning paid off in THIS instance. Handling the bike when it locked and went into a skid was pretty natural and did not come as a surprise. I stayed up, the bike stayed up and steady and I felt like I controlled it well with my lower body. (The front tire was free rolling, no brake applied)

However, troubled:

2) When the car pulled out, I immediately grabbed the front right lever, which on mostly all bikes is the front brake. I'm afraid if I were on a fullsize bike I might have face planted from such a reaction. Also is the factor of the rear brake was on the handlebar, rather than the foot brake.

3) Feeling the bike, when it skid and I had slowed enough to let go of the brake, I'm wondering again, if it was a fullsize bike, would that same action have put me into a high side.

4) Should I have swerved instead of braked?

Anyhow, I'm just rethinking the situation and how it played out. I hope I did something correct (yes, I know, MSF, its in the calendar, and I have been studying the classroom portion). And whatever I didn't do correctly I'd like to practice so that it comes naturally when I need that reaction again. I'm open to your thoughts, criticism, and general musings. I realize this wasn't a 'regular bike' so those variables muck the water. But I still was placed in an emergency situation that required quick action. I'd like to evaluate it and learn what I can.

Re: Dirtbike + side street intersection = rear brake lockup

Posted: Thu Jun 29, 2006 5:13 pm
by black mariah
Shorts wrote: 2) When the car pulled out, I immediately grabbed the front right lever, which on mostly all bikes is the front brake. I'm afraid if I were on a fullsize bike I might have face planted from such a reaction. Also is the factor of the rear brake was on the handlebar, rather than the foot brake.
But it's the REAR brake on that bike, and you knew that. Different bike, different story. Your brain thinks faster than you do, just let it do its job and don't over analyze.
Shorts wrote: 3) Feeling the bike, when it skid and I had slowed enough to let go of the brake, I'm wondering again, if it was a fullsize bike, would that same action have put me into a high side.
Depends on your ability. I used to do crap like this on my bike all the time (my grandparents lived in the desert and had dirt roads that NOBODY drove down). Hit the brake, lock the wheel, sling it sideways and sliiiiiiiiiide. It's a dirtbike. That's how you go fast.:laughing:
Shorts wrote: 4) Should I have swerved instead of braked?
No clue. Wasn't there, don't know what kind of distance you were afforded, and can't really say one way or the other what would have been better.

You didn't crash, which is the important bit.

Posted: Thu Jun 29, 2006 5:47 pm
by Shorts
True, I didn't crash, and I'm happy about that. Kinda like a pilot, any landing you can walk away from is a good landing :laughing:

Posted: Thu Jun 29, 2006 6:58 pm
by Shorts
On a nonrelated note, I just sold the dirtbike. I'm compiling funds for the new bike. Its going to a good home, a fella getting it for his boy. He was pretty pumped about getting on it and he just ordered his helmets and gloves too. Though if I had to say, the dad was more excited about it than the son was :D

Posted: Thu Jun 29, 2006 7:00 pm
by VermilionX
Shorts wrote:On a nonrelated note, I just sold the dirtbike. I'm compiling funds for the new bike. Its going to a good home, a fella getting it for his boy. He was pretty pumped about getting on it and he just ordered his helmets and gloves too. Though if I had to say, the dad was more excited about it than the son was :D
i wish my dad bought me a motorbike when i was young... i could have been pro by now ...or dead. :laughing:

Posted: Thu Jun 29, 2006 7:07 pm
by Shorts
lol nah, starting early on dirtbikes just calluses your body so you're not soft meat on street bikes :muscles:

Posted: Fri Jun 30, 2006 4:05 am
by DivideOverflow
On the streetbike, if you lock-up the rear brake, just keep it locked until you come to a full stop. If it slides to an angle and you release, it could cause a highside when it tries to snap back straight (generally on pavement).

On a street bike, you will have to get used to not locking up the front, as that will generally do very bad things. If the front tire starts to skid, you are supposed to release it immediately, and re-apply.

Braking was not the wrong choice here, in my opinion. That car could have pulled out if you tried to swerve around it, which would be a lot worse if you managed to be in front of him at the time.

On a streetbike, you should practice enough to learn the limits of your brakes before they start to skid (on various road conditions, like wet, dry, sandy, etc). You always stop faster if your wheels have traction.