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View Full Version : Why do we highside?



Sean
Thu Sep 18th, 2008, 08:17 AM
As I get faster (little by little) I am starting to think about the effects of taking corners at higher speeds. Lowside is easy to understand (been there, done that) but I'm curious about it's evil counterpart, the highside. Why does it happen? What are some reasons? Maybe some people with experience (regretfully) can help.

I only know of two reasons why one would highside right now:
1. to strong of acceleration out of a corner
2. tires sliding and then then get good grip

Can you help me understand this a little further....so I can avoid it. Thanks.

Slo
Thu Sep 18th, 2008, 08:21 AM
To me, my little highside was an extension of a low-side being that the tires caught traction after the initial loss of traction. I'm sure there are many factors and examples but this was my situation.

McVaaahhh
Thu Sep 18th, 2008, 08:23 AM
3. We're riding a borrowed bike. 8)

*cough* Scott *cough* Chris *cough*

Sean
Thu Sep 18th, 2008, 08:25 AM
3. We're riding a borrowed bike. 8)
I thought that was exclusive to Chris and Scott?

MetaLord 9
Thu Sep 18th, 2008, 08:34 AM
the reason you highside is because your rear tire comes out of traction & then suddenly comes back into traction being misalianged with the front while the front remains in traction. bike tries to stand up & right itself, tossing you in the process. Whatever you to do get there (i.e. coming out of a corner too hard & breaking the rear loose, hitting gravel & having the tire slide out & catch, etc.), that's what happens (rear loses traction)

Sortarican
Thu Sep 18th, 2008, 08:34 AM
As far I know, #2 is the Alpha and Omega of the highside.
Break loose....hook up....highside.

The thing that frightens me is the slow speeds at which it can happen.
Granted, it's easier to save at the lower the speed, but I almost highsided the other month doing about 25mph.
Scarey how much kenetic energy is stored in your body and bike at even low speeds.


Then again, like Brian said, there's people here with much more experience with H/S's.

Scott......Chris.....Bob......oh yeah **cough**cough**.

McVaaahhh
Thu Sep 18th, 2008, 08:46 AM
Scarey how much kenetic energy is stored in your body and bike at even low speeds.


I thought that was from bad chinese food at lunch? :dunno:

Sortarican
Thu Sep 18th, 2008, 08:51 AM
I thought that was from bad chinese food at lunch? :dunno:

You notice Taco Bell doesn't sponsor riders.....coincidence?....I think not.

Sean
Thu Sep 18th, 2008, 08:55 AM
Taco bell has nothing on the morning after effects of the dreaded, dell taco!!!!!
//I digress, back to the topic at hand

Sortarican
Thu Sep 18th, 2008, 09:09 AM
//I digress, back to the topic at hand

....ahhhh....if we must.:(

The toughest thing to learn is avoiding the natural knee-jerk reaction to let off the throttle when the ass end breaks loose.

Dirt riding as a kid has saved my ass in the past.
But it's been a long time since I road around purposely breaking it loose.

Racer types, what's your technique? Feather the throttle, stay on it hard?
Anything you practice to get you out of a H/S?

rybo
Thu Sep 18th, 2008, 09:29 AM
So I have some experience with this topic, as has been noted above.

The highside is generally the result of the back of the bike losing traction and then suddenly regaining it. The rear wheel being out of line with the direction of travel and gripping means that something has to give, and you fall off. That part is well established. WHY do we end up in this situation?

There are a number of reasons, some have already been covered:

1) Getting on the gas too hard/ too soon exiting a corner - causes the rear wheel to spin and slide. Natural reaction to this is to close the throttle, at which point the rear tire slows to ground speed and regains traction.

2) Carrying too much lean angle through the corner to the exit. As you get near the very edge of the tire the size of the contact patch decreases, when this happens the amount of available traction also decreases. Compound this with the edge of the tire having a smaller circumference than the middle and you also effectively lower the gear ratio. Turn on the throttle here and you have an increased ability to spin the rear wheel. Because your leaned WAY over the bike really steps out in this scenario and your desire to close the throttle is almost irresitable.

3) Missing your apex - This is what happened to me at Miller. I missed the apex of the corner and had to turn harder and later in the turn than I had on previous laps. I still used my same marker for opening the throttle though, so I was leaned over further and still turning when I opened the gas. In conversation with Mr. B Bostrom after the accident he said this was an extremely common cause of the highside. If you hit your mark and are going too fast, then you tend to lowside the bike. It's missing the apex and trying to continue at pace that can cause the highside.

4) If you are using the rear brake at the track (I am not) it is possible to highside by locking the rear wheel going into the turn and then letting off the brake and losing the rear end that way. I've never seen it happen in person, but I'm sure it's possible.

For me the best thing I can do when I get into a situation with the rear wheel spinning is to continue to hold the throttle where it is (not open it further or close it). The bike is like a giant gyroscope and it WANTS to stay in the plane it's in right then. If I can keep the throttle at it's existing position eventually the bike will catch up to the wheel speed and straighten out. For an example of this on film catch the last part of the GP race at INDY. Rossi has a BIG moment where the rear steps out BOTH directions in about .2 seconds. He doesn't even break his tuck, holds the throttle where it was and the bike straightens itself out.

The other thing for me is to try not to get into the situation in the first place. Working hard at hitting your marks every time, every lap (even warm up and cool down laps) is one really good way to avoid getting into the highside situation. Working to improve progressively (get fast - slow) is also a good way to not put yourself in greater danger of crashing. Trying a new line? do it at 80% the first few times through, get the brain and body used to a NEW picture before taking it at speed. Trying to move the braking further into the corner? Do it 10 feet at a time, not 50.

That's all I've got for you...hope it helps.

s

Sully
Thu Sep 18th, 2008, 09:35 AM
Just don't do it Sean, then we won't have to analyze why it happened ... Easy enough, right ? ;)

pilot
Thu Sep 18th, 2008, 09:43 AM
http://lh4.ggpht.com/davedragondave/SH4j1dNEaXI/AAAAAAAAGmk/_q4_Tmr-o8k/image_thumb%5B1%5D.png?imgmax=800

Sortarican
Thu Sep 18th, 2008, 09:56 AM
.....

Fixed it for ya Pilot:
9390

dragos13
Thu Sep 18th, 2008, 10:09 AM
The number one reason, IMO, for beginner riders to highside on the track is:

CHOPPING OFF THE THROTTLE

When you feel the rear tire sliding out, its not always a bad thing. Just make sure you are hanging off the bike, keep steady throttle and push the bike upright. If you can avoid the instinct to chop the throttle, you will be ok.

Sortarican
Thu Sep 18th, 2008, 10:33 AM
...If you can avoid the instinct to chop the throttle, you will be ok.

That exactly it. "IF" you can resist.

Last track day I (accidently) broke it loose in 2 and was able to stay on the throttle and actually went through it faster than I normally do.
Marc captured it on film....it's my wallpaper now.:)
9391

konichd
Thu Sep 18th, 2008, 10:41 AM
When in doubt, THROTTLE OUT!

Sean
Thu Sep 18th, 2008, 10:43 AM
Awesome Scott! That helps a lot, thanks for the detailed info.


Just don't do it Sean, then we won't have to analyze why it happened ... Easy enough, right ? ;)
Thank you Capt. Smartass for that insightful lesson on life.


The number one reason, IMO, for beginner riders to highside on the track is:

CHOPPING OFF THE THROTTLE
And that's how I lowsided too! It was a noob mistake which resulted in a dirt sandwich. Good tip, I can see a natural inclination to chop it.

Sully
Thu Sep 18th, 2008, 10:53 AM
Of course... that's what I'm here for... your pleasure only :p

dragos13
Thu Sep 18th, 2008, 10:53 AM
I think the only way to overcome the natural instinct to chop, is to just get practice at it. The more often the rear brakes loose (when in control) the more you'll get used to it and resist chopping. Then like Jeff said, you get thru the corner faster then before. Nice caption by the way.

BigE
Thu Sep 18th, 2008, 11:07 AM
Definitely some good info above. I don't really have anything to add but do have some examples.
McVaaah's pt. 3. On a borrowed bike. I almost HS'ed off a guy's bike at Pueblo. Reason was Scott's #2. The owner of said bike was off to the side taking pics so I decided to come around with my knee down. Well, as soon as I got my knee down the rear end lit up. I just stayed on the gas while pushing the bike upright (as Drago stated). Once it caught traction I got bucked into a classic flying W, landed back on the bike and even though a Mille isn't a dirt bike, went off roading. That was actually scarier than the highside and buckoff because I was going offcamber on alfalfa or whatever weeds are by the track, and they were nice and green, ie. LOTS of water in them and shedding off. It was like riding street tires on ice. All ended well enough though, no crashed bike, no crashed me.

Scott's #4 and Pilot's lil diagram apply more to street than track, IMHO. Scott's point happens tons on dirt bikes (that's how most dirt highsides happen in my experience, which back in the day was quite a few). On a dirt bike you brake slide into corners and if things don't happen right on the exit...the result is a catapult. Been there, done that, it sucks.
As for Pilot's diagram, I had a Harley dude highside in front of me going straight down 287. He locked the rear wheel up, did two fishtails and launched himself on three.

The best advice is to stay steady on the gas and as always look where you want to go.

Aracheon
Thu Sep 18th, 2008, 11:44 AM
3. We're riding a borrowed bike. 8)

*cough* Scott *cough* Chris *cough*


I keel you. :doublefinger:


As far I know, #2 is the Alpha and Omega of the highside.

Scott......Chris.....Bob......oh yeah **cough**cough**.

:lol: :lol:







:doublefinger:


The number one reason, IMO, for beginner riders to highside on the track is:

CHOPPING OFF THE THROTTLE

When you feel the rear tire sliding out, its not always a bad thing. Just make sure you are hanging off the bike, keep steady throttle and push the bike upright. If you can avoid the instinct to chop the throttle, you will be ok.

That might have been what happened to me. Elden said I had the bike leaned as far over as it'd go when the rear slid out on me, and I probably instinctively chopped it because of the angle. When I drifted out of T5 on the first lap of that race, I didn't chop it... and miraculously... the bike stayed upright! :D

bodhizafa
Thu Sep 18th, 2008, 12:17 PM
When in doubt, THROTTLE OUT!


I have to memorize that.

konichd
Thu Sep 18th, 2008, 12:37 PM
If you have a Kawi its just this easy!

http://www.youtube.com/watch?v=6s44KOINBB0

Sean
Thu Sep 18th, 2008, 02:04 PM
If you have a Kawi its just this easy!

http://www.youtube.com/watch?v=6s44KOINBB0
That vid is pretty cool. Must have been a yamaha engine with a kawi body, otherwise I don't think it's possible to get that much hp?

Thanks again for the tips everybody. Now lets have all of the MRA crew show me how it's possible, to not do it, all weekend! :hump:

455bird
Fri Sep 19th, 2008, 12:33 PM
I've read in quite a few places to stay steady on the throttle (don't increase or decrease) like many have said here, but what prevents this situation from turning into a low side? I've also heard to steer into a skid. Do you only want to do that in the example that Pilot posted? It seems that if you got on the throttle to hard out of a turn and then made a steering input you would just upset the geometry of the bike even more.

rybo
Fri Sep 19th, 2008, 12:55 PM
I've read in quite a few places to stay steady on the throttle (don't increase or decrease) like many have said here, but what prevents this situation from turning into a low side? I've also heard to steer into a skid. Do you only want to do that in the example that Pilot posted? It seems that if you got on the throttle to hard out of a turn and then made a steering input you would just upset the geometry of the bike even more.

Hey Tyler,

You make some good points. I'll respond.

1) Trying to stand the bike back up onto it's wheels keeps it from becoming a lowside. Also, that the ground speed and the wheel speed are matching slowly (bike is still accellerating, even if the wheel is spinning). You are going to generally be doing this as most highsides are happening at corner exit anyways. Even if it doesn't work, I'll take the lowside over the highside any day.

2) Yes, counter steering will help keep the back of the bike from coming all the way around. The good news about this is that it's almost instictive to do.

mastap07
Sun Sep 21st, 2008, 10:15 AM
i am a victim of "chopping the throttle off..." it happens so fast your natural instinct is to let off, good thing i was only in a parking lot and only broke my wrist lol definately not fun but its good experience!

pilot
Sun Sep 21st, 2008, 12:17 PM
The bike will naturally steer into the skid (point down the road). This is the path of least resistance for the rolling front wheel. Rider input, and a battle between the arms and hands in a feedback loop of countering each other plays a great roll in the bike flipping the rider off. There have been many a rider bucked off (up, left, right, forward, backward) only to have the bike right itself and then continue on down the road. We only need to remember the vivid situation in which the bike and rider came off turn seven where the rider bailed/was thrown off and the bike said, "Fine, I'll keep on going myself," until Matty made a gallant effort to stop it.

pilot
Sun Sep 21st, 2008, 12:21 PM
i am a victim of "chopping the throttle off..." it happens so fast your natural instinct is to let off, good thing i was only in a parking lot and only broke my wrist lol definately not fun but its good experience!In order to break this "habit" or SR as Code puts it, a rider must practice staying on the gas. This takes a dedicated effort and for some, it works to actually talk out loud in your helmet to oneself saying, "gas, gas, gas." Then in an emergency, muscle memory will take over.

You really don't have time to think this one out.

CaneZach
Mon Jan 5th, 2009, 03:56 PM
The number one reason, IMO, for beginner riders to highside on the track is:

CHOPPING OFF THE THROTTLE

When you feel the rear tire sliding out, its not always a bad thing. Just make sure you are hanging off the bike, keep steady throttle and push the bike upright. If you can avoid the instinct to chop the throttle, you will be ok.

+1!!! Biggest problem for just about every inexperienced rider is chopping the throttle, but their other problem is poor throttle control to begin with. Rolling the throttle should be a smooth action, not cracking it. When you feel the rear start to slide out a little, keep it steady on the throttle. Chopping the throttle is like hitting the brakes: it causes the weight distribution to be upset from about 40/60 front to rear (± 5%) during the turn to about 60/40 or greater front to rear.

DeVeck
Fri Jan 9th, 2009, 07:10 PM
I just wanted to comment that the advice here is really good.

From what I have read it sound similar to fish tailing a car? like...increasing the throttle on a car slightly while the rear end slides out actually corrects because it's forcing the vehicle to straighten itself out...

Am I close? or did I totally miss the point of the lesson?

CaneZach
Sat Jan 10th, 2009, 12:28 AM
I just wanted to comment that the advice here is really good.

From what I have read it sound similar to fish tailing a car? like...increasing the throttle on a car slightly while the rear end slides out actually corrects because it's forcing the vehicle to straighten itself out...

Am I close? or did I totally miss the point of the lesson?

Kind of. Motorcycles, technically being articulated vehicles, automatically turn the steering wheel (the front wheel, not the steering wheel like a car has) into the direction of the rotation. In other words, think of a motorcycle as a semi tractor towing a trailer. Everything from the front forks/bars back would be the trailer, while the forks are the actual semi. Once the rear starts to rotate around, the front wheel is automatically turned in the direction of the slide so all you need to do is stay on the throttle to retain control.

ZX9Rider
Sat Jan 10th, 2009, 12:38 AM
If you have a Kawi its just this easy!

http://www.youtube.com/watch?v=6s44KOINBB0

If everyone gets a kawi... then we have to deal with threads like... "How do you resist the urge to show off?"

Also there is a book out called "twist of the wrist II" that is a must read of riding sportbikes at top speed.

Danjo
Sat Jan 17th, 2009, 08:08 AM
That vid is pretty cool. Must have been a yamaha engine with a kawi body, otherwise I don't think it's possible to get that much hp?

Thanks again for the tips everybody. Now lets have all of the MRA crew show me how it's possible, to not do it, all weekend! :hump:


If everyone gets a kawi... then we have to deal with threads like... "How do you resist the urge to show off?"

Also there is a book out called "twist of the wrist II" that is a must read of riding sportbikes at top speed.

I am quite certain this link is an example of trail braking. Just wasn't sure people saw that from their comments. Cool video.

mtnairlover
Sat Jan 17th, 2009, 08:25 AM
#3...does hitting a boulder and going over the handlebars count as a high side?

I don't believe I'll get to the point of pushing myself on the track during track days to the point of high side. I'm git'n along in my years and I think I've seen about as much speed as I'm gonna see for my tastes. I want to make my later years as pain free as possible. But, knowing the physics of a track high side is good...just in case I feel like testing my resolve.;)

lightspeed
Sat Jan 24th, 2009, 11:18 AM
If you have a Kawi its just this easy!

http://www.youtube.com/watch?v=6s44KOINBB0


KIMS??

nwatkins
Tue May 19th, 2009, 03:05 PM
I did this one in 2002. My first year on the track. Was on street tires, ran out of ground clearance, chopped the throttle and landed in the grass somewhere with a broken ankle and bruised tailbone. Yea that was my introduction to high side. Notice the sparks from the gear shift or peg dragging. There was a drag mark on the shift lever. I miss that bike. :)

http://www.sportbikes.ws/attachment.php?attachmentid=4409&d=1034560339

BeoBe
Tue May 19th, 2009, 03:07 PM
lol, i just had to see this one because of my sig..