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Understeering.. What To Do With The Throttle?


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Hi,

 

yesterday I went for a ride, it was a little cold outside, maybe 8 Celsius, I thought I had my tires warmed up pretty good though (PP2CT on a SC59 Fireblade, both front an rear at about 80% profile) I quickflipped into a right turn going about 70 kmh and experienced an understeering of the front tire just when I had reached my intended lean angel (actually the bike went beyond that intended angle while understeering), Before flipping the bike I had not rolled off the gas completely, it was maybe a quarter or so rolled on, I hadn't been accelerating though. Obviously I didn't have as much grip as I had thought, the resistance to the steering impulse had felt normal though , I was "a little surprised" by the situation :lol:

 

Anyway, there I was with my understeering front, and what I did was to leave the throttle as it was (1/4 on) and wait for the front tire to catch again (which it eventually did) , it took nerves not to roll off the throttle though :blink: . My question now is : Could I have done even better by rolling on the throttle in that situation (which I didn't have the nerve to do) ?

(the moment when the understeering started was when I would have rolled on the gas under normal circumstances)

 

Thank you in advance.

 

Uli

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I may be making some incorrect assumptions, but let's start with this... Yes, getting on the gas would've been a good solution. Your rear tire had traction, you were at desired lean angle, and you were ready to roll-on. Getting on the gas would take weight off the front tire and allow it to stabilize while the rear took you through the turn.

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By understeering do you mean actually sliding or running wider than you expected. Adding gas would extend the forks and increase trail which would slow steering and add to understeer. If it was actually sliding then adding gas would be iffy as it would reduce weight on the front and thus grip. Although I could be totally wrong!!

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By understeering do you mean actually sliding or running wider than you expected. Adding gas would extend the forks and increase trail which would slow steering and add to understeer. If it was actually sliding then adding gas would be iffy as it would reduce weight on the front and thus grip. Although I could be totally wrong!!

I'm not entirely sure I know what he meant either :), but I assumed he meant sliding the front end.

 

Since he said he was at his desired lean angle and ready to get on the gas, he had completed his steering. Once steering is complete we want to get the weight to the rear so it can stabilize and steer the bike. Getting on the gas changes the weight distribution to the rear and keeps the bike on line. The rear end steers the bike at that point, provided he doesn't/didn't add new input to one of the bars.

 

I'm trying not to overthink the explanation, but I'm probably not succeeding :blink:

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Hi guys, :)

thank you for you answers, By understeering I mean that the front tire was not yet sliding totally but it didn't give me any feedback either so the bike leaned ( or I should rather say tilted) over more than I wanted it to. The rear tire seemed fine though (not sliding or feeling unstable at all). It was just like when you have a new front tire and it's not scrubbed in yet at the outsides and you've forgotten it's still new... know what I mean ?

 

BTW I don't blame the tires, it was my own fault, that curve is actually a ramp up to the Autobahn, normally there's very much traffic but this time I was all by myself and I simply overdid it.

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I think that makes sense. A small front slide would cause the bike to turn-in a bit more than intended, thus feeling more leaned over. Since the front end slide is usually caused by the front end being overworked and losing traction, take the weight off the front and it should begin working again. Best way to redistribute weight to the rear is to get on the gas :).

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I think that makes sense. A small front slide would cause the bike to turn-in a bit more than intended, thus feeling more leaned over. Since the front end slide is usually caused by the front end being overworked and losing traction, take the weight off the front and it should begin working again. Best way to redistribute weight to the rear is to get on the gas :).

 

Think you're right, still it takes nerves to get on the gas in a situation like this :) , I need to try it in a controlled environment.

 

Thank you for your answers, (Brad and Rick) :)

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I think that makes sense. A small front slide would cause the bike to turn-in a bit more than intended, thus feeling more leaned over. Since the front end slide is usually caused by the front end being overworked and losing traction, take the weight off the front and it should begin working again. Best way to redistribute weight to the rear is to get on the gas :).

 

Think you're right, still it takes nerves to get on the gas in a situation like this :) , I need to try it in a controlled environment.

 

Thank you for your answers, (Brad and Rick) :)

 

To summarise my understanding, you said that the "understeer" happened when you would USUALLY roll on the throttle... So it sounds like you were waiting to see IF you should roll on the throttle. Perhaps sticking with your PLAN to roll on the throttle, as per Throttle Control Rule # 1, you would not have ever felt that understeer.

 

As soon as possible after the bike is leaned over, the throttle should be rolled on smoothly, evenly, and continuously through the remainder of the corner...

 

Also, remember that when you lean over the bike at a constant throttle, you are actually decelerating a little bit, both due to the constant throttle as well as the leaning over to a smaller part of the tyre... and you need the roll on just to maintain the same speed, much less shift the weight to the rear... in order to achieve 40-60 weight distribution.

 

That is my understanding of the situation... Even if your question was answered already, I like to put it in my words so I go over it in my head again, and give the opportunity for any coaches or more experienced persons to correct me if am wrong...

 

J.

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To summarise my understanding, you said that the "understeer" happened when you would USUALLY roll on the throttle... So it sounds like you were waiting to see IF you should roll on the throttle.

 

Hi CBRKID,

I didn't hesitate to roll on the throttle, I wasn't waiting for anything, the understeering started the very moment I wanted to get in on. Sure the whole thing wouldn't have happened in the first place if I had rolled on a tenth of a second earlier but I wanted to finish steering first.

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Yeah things happen real quickly don't they??

 

I lost my front in the cold a while back (2 degrees out), with cold tyres (just left work about 5 minutes before) and it was the same basic thing... Felt the lean angle all of a sudden go lower, without my input, and next thing I was on my arse, bike skating down Park Lane in the middle of London!!!

 

And as you say, not that I hesitated (so maybe I asked using the wrong wording), but I believe I did not get on the throttle enough, as I was trying to crack it on very gingerly (gently)... I THINK that if I got into the throttle a bit more decisively, I would not have binned it...

 

I am still practicing getting into the throttle quicker and quicker just because I KNOW that it is the right thing to do, but as you say, difficult to force yourself sometimes... ;)

 

Jason.

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I am still practicing getting into the throttle quicker and quicker just because I KNOW that it is the right thing to do, but as you say, difficult to force yourself sometimes... ;)

 

Jason.

 

Working at it

 

:)

 

Uli

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Personally, I find the bike heading for the outside of the corner - and potentially clean off the road if not adjusted - if I open the throttle too early. It makes, for me, a normal corner into a scary fighting match. This is if I use enough throttle to actually accelerate. The greater the acceleration, the greater the tendency to run wide.

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Hi,

 

yesterday I went for a ride, it was a little cold outside, maybe 8 Celsius, I thought I had my tires warmed up pretty good though (PP2CT on a SC59 Fireblade, both front an rear at about 80% profile) I quickflipped into a right turn going about 70 kmh and experienced an understeering of the front tire just when I had reached my intended lean angel (actually the bike went beyond that intended angle while understeering), Before flipping the bike I had not rolled off the gas completely, it was maybe a quarter or so rolled on, I hadn't been accelerating though. Obviously I didn't have as much grip as I had thought, the resistance to the steering impulse had felt normal though , I was "a little surprised" by the situation :lol:

 

Anyway, there I was with my understeering front, and what I did was to leave the throttle as it was (1/4 on) and wait for the front tire to catch again (which it eventually did) , it took nerves not to roll off the throttle though :blink: . My question now is : Could I have done even better by rolling on the throttle in that situation (which I didn't have the nerve to do) ?

(the moment when the understeering started was when I would have rolled on the gas under normal circumstances)

 

Thank you in advance.

 

Uli

 

First of all, great job, because you knew you shouldn't roll off, and you didn't, so you saved yourself from crashing! And I assume you must have stayed loose on the bars, since the bike corrected itself and regained grip, right?

 

There seems to be a bit of debate whether you were actually sliding the front tire - can you think of any other reason that the bike would lean over farther than you expected? I can't. I am not an expert, but in my experience the bike leaning over more than I told it to, and sudden lack of feedback from the front, are excellent indicators that the front tire is, indeed, sliding.

 

Do you think both sides of the tire were warmed up? Is there any possibility that the road surface was slick in that spot, or that you hit sand, or oil, or other liquid?

 

To answer your question, rolling on a bit probaby would have helped, by decreasing the load on the front tire, and stabilizing the suspension - but you did more right than you did wrong (as evidenced by the fact that you recovered the slide!) AND you carefully observed what you felt, which was smart and perceptive, and will make you that much more prepared to handle something like that in the future. You are correct that you must finish your steering action before you roll on (are you clear on the reason why?) and if that slide occurred while you were still steering the bike, it seems likely that a cold tire or slippery surface caused the slide.

 

 

So after reading the various posts and thinking it over, I am wondering: what do YOU think really caused the slide? And, what could / should you have done differently, if anything?

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Personally, I find the bike heading for the outside of the corner - and potentially clean off the road if not adjusted - if I open the throttle too early. It makes, for me, a normal corner into a scary fighting match. This is if I use enough throttle to actually accelerate. The greater the acceleration, the greater the tendency to run wide.

There are a number of possibilities... Do you know: are you completing your steering before you get on the gas? or, are you turning the bike too early? or, are you looking outward of your turn?

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I do look forward where I want to go, although I may get a bit interested in the edge of road if the bike gets too close for comfort - but the tendency to stand up and go wide comes first. I'm not turning the bike too early and I doubt I'm on the throttle before finishing the steering, although that is something I will pay attention to.

 

I should point out that the situations where this takes place is around slow hairpins in first gear, at higher speeds it doesn't seem to happen. So probably something I don't do right when I try to move away from my preferred method of turning on the brakes and get the bike quckly upright-ish before whacking the throttle open, making the corner more that of a V than a U.

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I can't help but wonder what the dew point was? What time, early morning, mid-day, evening? I've encountered a few situations where heading into work when it's warm enough to ride but not really warm (40f-45f) where temps and dew point were really close and with slightly cooler ground than air corners giving me a little wakeup with a small slip of the front end. Later in the same day...all is normal.

 

Just some thoughts. ;)

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So after reading the various posts and thinking it over, I am wondering: what do YOU think really caused the slide? And, what could / should you have done differently, if anything?

 

I think the tire was too cold for a quickflip like that, there was nothing wrong with the street surface, no oil, sand or anything, Next time when I feel the same situation coming on I'll roll on the throttle a little bit. You know, I was totally surprised because I thought I had had enough grip... well, , there wasn't ,

 

Thank you!

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I can't help but wonder what the dew point was? What time, early morning, mid-day, evening? I've encountered a few situations where heading into work when it's warm enough to ride but not really warm (40f-45f) where temps and dew point were really close and with slightly cooler ground than air corners giving me a little wakeup with a small slip of the front end. Later in the same day...all is normal.

 

Just some thoughts. ;)

 

Hello Gorecki :)

It was 10:30 am, When I left home it was 7 degrees Celsius, I had been driving around for about half an hour when I got to that corner. I'll take it more easy next time B)

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I do look forward where I want to go, although I may get a bit interested in the edge of road if the bike gets too close for comfort - but the tendency to stand up and go wide comes first. I'm not turning the bike too early and I doubt I'm on the throttle before finishing the steering, although that is something I will pay attention to.

 

I should point out that the situations where this takes place is around slow hairpins in first gear, at higher speeds it doesn't seem to happen. So probably something I don't do right when I try to move away from my preferred method of turning on the brakes and get the bike quckly upright-ish before whacking the throttle open, making the corner more that of a V than a U.

 

Hi Eirik, I had exactly the same problem you are describing at the start of my level 3 school. I kept running wide on the hairpin - fast corners no problem. It turned out that I wasn't adjusting my approach for the different types of corner. In the harpin I was turning and the instant I was leant over to my intended angle (and possibly slightly before too?) I was on the throttle and rolling it on. When I say rolling, it was waaaay to fast - gas greedy as they say. The solution, as provided by Bullet, was to roll on much more gently in the longer corners. I didn't have a problem with the fast ones, as the more rapid application was working fine!

 

Now I try and consider each corner individually, seemingly there is no 'one size fits all for throttle application and the extremes of hairpin, followed by faster turn shows this up nicely!

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Yes, that sounds like what I've experienced; every time I try to get out fast using plenty of throttle I end up wide, if I wait a little longer before applying serious throttle there is no problem. Which means it usually isn't a problem - it only became one when I tried to accelerate early after reading - and probably not understanding correctly - TWOT2.

 

Thank you for your reply, slobdog :)

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Hi guys, just thought I should let you know, today I had a similar situation as described in my above post, this time with my CBF1000, I almost lost the front , instead of freezing and doing nothing I rolled on the throttle and <drumroll> .... the bike immediately stabilized ,B) .... Thank you !

 

Uli

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If you were being pushed wide, have you ever heard of the hook turn? Andy Ibbott explains it on a Superbike UK video on YouTube. The reaction of the bike is the same you'll get from trail braking.

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Hi guys, just thought I should let you know, today I had a similar situation as described in my above post, this time with my CBF1000, I almost lost the front , instead of freezing and doing nothing I rolled on the throttle and <drumroll> .... the bike immediately stabilized ,B) .... Thank you !

 

 

 

Sweet!, so temps had nothing to do with it. B)

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Hi guys, just thought I should let you know, today I had a similar situation as described in my above post, this time with my CBF1000, I almost lost the front , instead of freezing and doing nothing I rolled on the throttle and <drumroll> .... the bike immediately stabilized ,B) .... Thank you !

 

 

 

Sweet!, so temps had nothing to do with it. B)

 

Not in this case, the road was a little wet, in the first case the front tire was too cold alright.

:)

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