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Front End Tuck


noamkrief
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Hey everyone. I'm a new rider and i don't lean over 40 degrees.

I was out on my favorite road that has alot of 180 degree turns at around 35mph and I had the following happen to me 3 times around the same right hander:

 

It's a slightly decreasing radius 180 degree turn uphill, I go in and lean the bike over hanging off, maybe 35 degrees lean, no knee touching the ground because I would only attempt to drag knee on the track (still never dragged knee).

 

Nice the radius decreases and gets me every time, I ease off the throttle mid corner. I know it's bad, because I need to be on the throttle, but I'm NOT chopping the power. Just gently easing off of it. After about 1-2 second of having no throttle, the bike slows down severely because of the up hill attitude, and the front end tucks!!!!

 

Here is what I mean by the front end tucking. On the right hand turn - the bar instantly turns to the right about 10-15 degrees i'd say. And as that happens, the entire bike instantly leans over another 10 degrees. Almost as if it's free falling down towards a 90 degree lean.

 

Needless to say - it was scary!

 

For the next 3 runs on that same turn the same exact thing happened. Every single time, I instantly added a fair amount of throttle which seemed to stand the bike up a little bit. From my car racing background, adding throttle is a natural reaction anytime someone happens I don't like - I'm thankful for that.

 

I need to understand what happened there. Obviously me not being on the throttle during the corner was the mistake.

 

What is this front end tuck all about?

 

Did my front tire lose traction?

 

Why did it lose traction if I was already off the throttle for more than a second and weight transfer was not an issue? (I can understand if this happened right after if I chopped the throttle transferring weight to the front, but i've already been off throttle for a while)

 

Most importantly, why did the handle bars steer to the right all by themselves?

 

Would there be any situation where the handlebars would steer the opposite direction of the corner due to front end grip loss?

 

Are there any warning signs to this issue I was not aware of? I would compare this to a snap oversteer in a car - no warning!

 

 

This happened to me about 1 week ago. Just now it's sinking in my brain that I almost low sided. It's serious stuff! When I was actually riding - I just swallowed it as instability of the bike...

 

I would appreciate any feedback.

 

PS - see attached photo - this is what I mean by front end tuck. That's not me riding - I don't lean that far, and I try to hang off my entire body.

Noam

post-23818-0-37688700-1354580600_thumb.jpg

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Here is what I mean by the front end tucking. On the right hand turn - the bar instantly turns to the right about 10-15 degrees i'd say. And as that happens, the entire bike instantly leans over another 10 degrees. Almost as if it's free falling down towards a 90 degree lean.

 

My guess is you have the order of these events backwards. You mentioned that the bike slows down "severely" due to the uphill nature of the corner, I would venture to guess there is a loss of momentum to the point the bike can no longer maintain its trajectory and is starting to fall over and the sudden "tuck" of the handlebars is the bike attempting to right itself before it does.

 

As for the bars steering all by themselves, I'm sure a quick search of YouTube will find you any number of videos of a motorcycle violently ejecting its rider only to right itself and continue on down the road. That's because motorcycles like to be upright and go in a straight line and are pretty good at getting themselves back to that state when the rider doesn't get in the way. A motorcycle can recover from all sorts of being upset simply by letting go of the hand grips and letting the suspension do what it wants to right itself.

 

Tyler

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A lot of questions in your post. lol But that is cool.

  • By your description, it doesn't sound as if your front gave up any traction.
  • Even a slight roll off the throttle will cause some weight to transfer from the rear to the front of the bike. When this happens, the front tire's contact patch spreads and increased friction will countersteer the bike all by itself. It seems, you have learned that all on your own. ;)
  • As far as a warning sign.... they are subtle but there. The easiest one to feel is your body weight wanting to go forward on the bike. Also, front will get a "heavy" or "digging in feeling" as you get closer to what you describe as "tucking".
  • Finally and most importantly yes, you will want to stay on the throttle as you have also learned all on your own.
  • Aside loss of traction, a tank slapper, large bumps in the road or rider error, I know of nothing else that could send the bars in the opposite direction.

The scary feeling you had was a voice telling you something is not right. Make sure you listen to them when they scream so loudly because they are not always that way.

 

And let me ask you this about decreasing radius turns. Where do you turn in and how do you think it would that affect how you proceed through this corner or any other given corner?

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If the bike "slows down severely", what does that tell you about the weight balance between the front and rear tires? Which tire do you think is handling the majority of the weight?

 

How about your arms - when you roll off and the bike slows severely, is there any weight transfer onto your arms?

 

If it happened in the same place each time, could there be a change in he surface? Something slick, or does the camber change? Or does the uphill get steeper right there?

 

A front end tuck usually IS an indication of loss of traction - just as you describe, the bars turn in, the bike leans more, and then... well, it either regains traction on its own when it hits better pavement (crossing over a wet pavement snake can feel like this), or you get on the throttle and shift some weight off the front tire, or it keeps sliding and you can lowside.

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I attacked the same twisty road (8 hairpins in 2 miles) yesterday and today for about 4 hours each day and you guys have predicted correctly!!! Go figure!

1st of all, it's a decreasing radius turn up hill. I was doing an early turn in and early apex - just typical newbie mistake!

 

Today I was working on looking as far as possible into the turn. That fixed my early turn in problem.

 

As "cornering master" stated: during that part of the turn that made my front end tuck multiple times - YOU ARE CORRECT - as the radius decreases, it goes from being uphill, to SEVERELY uphill. At the same spot, it also goes from great positive camber to no camber at all. You were so right! I just read your reply and that's exactly what I noticed earlier today riding there!

 

Another thing I was working on today is NO ROLL OFF during the corner. That's where I noticed for the first time that roll off during a lean doesn't only effect the balance negatively, but all my body weight was going to my arms all the sudden and lost tons steering ability because my arms became so tense! Once again - you were 100% accurate!

 

Just in case anyone is curious - this is the run I do. I'm working it in sections. It's very famous place here for bikers. Many wrecks - every weekend :( People dragging knees etc... I'm just there working on smoothness, visual skills etc...

 

http://goo.gl/maps/BhYjX

 

It's the 2nd hairpin (from point A) right hand 180 degree turn. Right before the exit - it turns tight and gets steeper.

 

This is me practicing on it yesterday. Only been riding for 3 months. S1000RR is my first bike. Never ridden anything before.

http://youtu.be/1diRW-iMFaA?hd=1

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Since you are working on visual skills, I invite you to give a thread I started a read. http://www.ninjette....ad.php?t=109933 It gets pretty deep if you haven't taken level 1 but Misti (a CSS coach) ensures that the basics are covered.

 

I enjoyed your video, thanks for sharing.

Thanks for posting the link - that is an interesting thread. I found I was doing a lot of head nodding while reading. I could totally visualize many of those things discussed and how many of them could (did) lead to danger (disaster). I am almost continually amazed at how critical good visual skills are to this game.

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Front end tucks are horrible. As others have said, it's basically down to overloading the front tire, with over-braking and going off-throttle being the main causes.

 

IME, some bikes are more prone to it than others. When I'm out road-riding one of mine, a long wheel-base Ducati, I'm very careful to limit the amount of front brake when negotiating tight down-hill bends. And make sure I'm clamped on with my knees.

 

Because, if not .....

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  • 3 weeks later...

Noam, I like the way you ride. Looks like a reasonable pace for that road, and you are always in total control (except maybe one tiny wander over the white line on the right). I especially like how you avoid approaching the center line too closely when apexing blind left handers. A lot of people make that mistake and it is only a matter of time until a vehicle comes from the other direction in position to remove your head for you.

 

Great video, beautiful road. Keep things in control like that and count yourself amongst the good guys in the sport.

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