Oversteer... The cure for understeer?

[Burning1]

We have a lot of really knowledgeable people in this forum, so I'd like to throw this question out there: Can overseer be used as an effective way of preventing and limiting under-steer? When I say over-steer, I mean kicking the tail end of the bike out a little bit.

Backstory: I had business in Scotts Valley this morning and decided to take my old tromping route of 9 > 35 > 92 > 280 to get back to work. It's been raining pretty hard, and a few of the corners and intersections can get a little tricky on the BMW Rockster. Now, my normal tendency is to keep a neutral throttle through those corners even though I know that I should be accelerating slightly. So, I've been building up my confidence to crack the throttle open and use a bit more of the rear tire grip.

I'm starting to feel a little more comfortable when the rear end steps out of line, and it started to hit me... By shifting the contact patch towards the outside of the turn, am I helping the bike to resist a front end slide?

Obviously, going too far is dangerous. But in theory, with the rear wheel pointing 90 degrees from the tangent of my cornering line, it should be impossible for the front wheel to tuck. Clearly, I would never want the rear wheel to point that far out, but it would support the theory that a little rear end slide can help to prevent a front end slide, both by supporting more of the total weight of the bike, and by providing a warning about low traction conditions.

Ultimately, my goal is not to slide around corners, just to understand the balance and to build confidence with the throttle, even when I'm afraid the rear end is going to slide.

So, what do you think? What should I watch out for?

 

[Cycle61]

I'm definitely interested in hearing the responses here....

 

[afm199]

Probably a tactic you are better off using on the track, and with experience. It's not something for novice riders to try.

Done all the time in the dirt/supermotos. A bit trickier on road bikes.

 

[CaptCrash]

That is a beautiful drift shot.

 

[Burning1]

Probably a tactic you are better off using on the track, and with experience. It's not something for novice riders to try.

Done all the time in the dirt/supermotos. A bit trickier on road bikes.

Absolutely true. I'm hardly novice though.

The problem is that I do ride in the rain. One tire or the other is going to slip, eventually. Edit: Again, my goal isn't to kick the tail out around corners, just to develop confidence and control so that if it slides, it does it at the rear tire not the front.

 

[Burning1]

I'm definitely interested in hearing the responses here....

I want to see that on a BMW R1150R.



Ahhh...

 

[Cycle61]

I want to see that on a BMW R1150R.

View attachment 294642

Ahhh...

 

[afm199]

Absolutely true. I'm hardly novice though.

The problem is that I do ride in the rain. One tire or the other is going to slip, eventually. Edit: Again, my goal isn't to kick the tail out around corners, just to develop confidence and control so that if it slides, it does it at the rear tire not the front.

Dude if you're not a novice you already know the answer.

 

[Burning1]

Dude if you're not a novice you already know the answer.

Is it fair enough just to say that I'm a novice power slider..?

 

[Bluenote]

We have a lot of really knowledgeable people in this forum, so I'd like to throw this question out there: Can overseer be used as an effective way of preventing and limiting under-steer? When I say over-steer, I mean kicking the tail end of the bike out a little bit.

Backstory: I had business in Scotts Valley this morning and decided to take my old tromping route of 9 > 35 > 92 > 280 to get back to work. It's been raining pretty hard, and a few of the corners and intersections can get a little tricky on the BMW Rockster. Now, my normal tendency is to keep a neutral throttle through those corners even though I know that I should be accelerating slightly. So, I've been building up my confidence to crack the throttle open and use a bit more of the rear tire grip.

I'm starting to feel a little more comfortable when the rear end steps out of line, and it started to hit me... By shifting the contact patch towards the outside of the turn, am I helping the bike to resist a front end slide?

Obviously, going too far is dangerous. But in theory, with the rear wheel pointing 90 degrees from the tangent of my cornering line, it should be impossible for the front wheel to tuck. Clearly, I would never want the rear wheel to point that far out, but it would support the theory that a little rear end slide can help to prevent a front end slide, both by supporting more of the total weight of the bike, and by providing a warning about low traction conditions.

Ultimately, my goal is not to slide around corners, just to understand the balance and to build confidence with the throttle, even when I'm afraid the rear end is going to slide.

So, what do you think? What should I watch out for?

I'd say your theory is correct , sliding the rear end a bit doesn't personally bother me much , losing the front end does.

That said you'd likely be better off practicing it in the dirt for a while , you'll find out just how far you can hang it out pretty quickly.


CAVEAT: modulate the throttle well and never ever just come completely out of the throttle quickly once that rear is hanging out a bit , to do so is a recipe for a highside , not too painful at lower speeds in the dirt but disastrous on the street.

Don't know if you have access to something like an XR100 and a short track but a bit of time with 'em can throw a lot of light on this for you.

And I'll openly state that dirt bike and short-track experience has saved my old ass quite a few times on the street.


And for what it's worth , an XR100 and a muddy track equates to a hell of alot of fun too........damn but I miss my Astro.

further caveat: hanging the rear out on the street can get you in trouble if viewed by the local constabulary.

B.

 

[Bluenote]

Absolutely true. I'm hardly novice though.

The problem is that I do ride in the rain. One tire or the other is going to slip, eventually. Edit: Again, my goal isn't to kick the tail out around corners, just to develop confidence and control so that if it slides, it does it at the rear tire not the front.

Corner with the power on and most times on the street it seems like the rear end breaks loose first , at least for me.

Now REALLY slick conditions like ice are a whole different story.



B.

 

[Burning1]

Good advise. In theory, the rear end shouldn't go way out of line unless rider input or road traction change quickly, and significantly. The further the rear end slides, the more resistance there is to sliding. In fact, the rear wheel has a huge amount of trail, and should self correct from minor disturbances, much like the front does when it encounters a bump.

I guess another good question would be this... How common is it to lowside under acceleration when the road surface is dry or wet, but free from surface hazards?]

 

[Ozymandias]

While I won't say I'm the best rider out there, I can hold my own in most situations. God knows there are plenty here that are hella better than me. But... I started riding when I was 8 "in the back 40" on a little honda 80 dirt bike. This is one of the reasons I'm a firm believer in riding dirt to learn first if you can. You learn how a bike feels when it's unsettled AND how to handle it.

Perfect example, I bought my FZ1 from a former racer friend of mine. Many years retired and not really used to triple digit horsepower as he was a harley racer for quite a few of those years.... long story. Anyway, my meager 135... he applied too much power coming out of a turn and lost it because it happened to fast. In his defense, he was over 55 when it happened but still.

Same thing happened to me at Sears this year coming out of the Chicane. The back started sliding out from under me because I gave it too much power to fast... my MANY years of ... well, driving MANY things fast kicked in and I just EASED off the throttle out of a reaction and didn't think about it until the bike was starting to settle again. The slide kept going for a second then snapped back under me. Of course it kind of bounced while it protested and made me raise out of the saddle a bit to protect the jewels but nothing bad happened.

Honestly, I would say spending some time in the dirt... even just a few months with a little 125 or whatever... powering that sucker hard. Nail the throttle. Let the ass wiggle under you. Get used to the feeling of it. It doesn't translate 100% to the street but it does give you a little bit of confidence one how to deal with... odd handling.

Sorry this was such a long post...

edit: oh and there was a video on here somewhere of someone reaming the piss out of his bike during practice or qualifying for motogp, I think and.... purely amazing. I looked but couldn't find it.

 

[JeffKoch]

By shifting the contact patch towards the outside of the turn, am I helping the bike to resist a front end slide?

I'm not quite sure what you're asking. Are you proposing to add more gas than usual in slippery conditions?

 

[Burning1]

I'm not quite sure what you're asking. Are you proposing to add more gas than usual in slippery conditions?

Not at all. I propose using the throttle properly in all conditions. I believe that a lot of the resistance to using the rear throttle comes from the rear stepping out. I propose that it's better to use it and have the rear come out than it is to be off it, and risk the front coming out.

Personally: my natural tendency is to roll off when I get nervious, rather than re-focusing and turning in. In wet and slippery conditions I find myself reacting by cornering with no throttle, or with a very neutral throttle. I'm not sure that what I'm doing really is safe.

This topic is also to explore motorcycle dynamics. I had a thought and understand the theory, but I don't have the experience to back it up.

 

[Ozymandias]

Not at all. I propose using the throttle properly in all conditions. I believe that a lot of the resistance to using the rear throttle comes from the rear stepping out. I propose that it's better to use it and have the rear come out than it is to be off it, and risk the front coming out.

Personally: my natural tendency is to roll off when I get nervious, rather than re-focusing and turning in. In wet and slippery conditions I find myself reacting by cornering with no throttle, or with a very neutral throttle. I'm not sure that what I'm doing really is safe.

This topic is also to explore motorcycle dynamics. I had a thought and understand the theory, but I don't have the experience to back it up.

The problem with letting off the throttle in a turn is that's usually when your front WILL step out because the weight is being shifted more to the rear rather than the front. Just like any other motorcycle riding, set the speed before the corner. It's 90% better to be at least neutral throttle while going through a corner. It's all about minute input in the rain. Easy on everything until you learn the limits. Even then... keep the input easy.

 

[Cycle61]

I so need to get in the dirt....

I've only had the back end on a sportbike come out of line a few times, and it's been an "Oh shit" every time, complete with the wrong panic reaction of chopping throttle and almost highsiding. Not proud of it, but there it is.

 

[Burning1]

The problem with letting off the throttle in a turn is that's usually when your front WILL step out because the weight is being shifted more to the rear rather than the front. Just like any other motorcycle riding, set the speed before the corner. It's 90% better to be at least neutral throttle while going through a corner. It's all about minute input in the rain. Easy on everything until you learn the limits. Even then... keep the input easy.

Of course. But understand that chopping is a panic reaction, something that's incredibly common among many riders. I believe that developing comfort with the idea that the rear end can slide might help a rider (me) to overcome the chop reaction and help to prevent low sides. I would not advocate forcing the rear end to come out.

It's a similar situation when using a neutral throttle... When something slides, it's up in the air weather it's going to be the front or the rear. I believe that it's better to keep on the throttle, so that the rear tends to go out before the front.

I think an important detail is that a gentle rear-end slide tends to self correct, whereas a front end slide tends to get worse if not corrected immediately. Given that the rear end might help prevent the front from going down, and that it's easier to recover from, I believe that it might be safest for an experienced rider to balance traction gently in that direction.

Again, I believe in the concept, but I'm not sure I fully understand the practical implications. I would not advocate this to an inexperienced rider.

 

[Ozymandias]

Of course. But understand that chopping is a panic reaction, something that's incredibly common among many riders. I believe that developing comfort with the idea that the rear end can slide might help a rider (me) to overcome the chop reaction and help to prevent low sides. I would not advocate forcing the rear end to come out.

It's a similar situation when using a neutral throttle... When something slides, it's up in the air weather it's going to be the front or the rear. I believe that it's better to keep on the throttle, so that the rear tends to go out before the front.

I think an important detail is that a gentle rear-end slide tends to self correct, whereas a front end slide tends to get worse if not corrected immediately. Given that the rear end might help prevent the front from going down, and that it's easier to recover from, I believe that it might be safest for an experienced rider to balance traction gently in that direction.

Again, I believe in the concept, but I'm not sure I fully understand the practical implications. I would not advocate this to an inexperienced rider.

Oh absolutely! It's all about throttle control. That's why I'm one of those guys that recommends dirt riding first. You're going to spill, sure. But you'll spill where the other people you have to worry about are other riders. You'll learn your limits of pushing into a turn and letting it slide around. You'll learn what it feels like when it breaks loose.... all that good stuff

But you're right... if the front end starts to slide, the ONLY action you have is to stand it up and that's if you're quick enough to catch it. The Edwards video is a perfect example of it.

That's the reason I recommend dirt a bit.

 

[Bluenote]

I so need to get in the dirt....

I've only had the back end on a sportbike come out of line a few times, and it's been an "Oh shit" every time, complete with the wrong panic reaction of chopping throttle and almost highsiding. Not proud of it, but there it is.

Exactly correct , and the consistent reaction of a great many folks on sportbikes with no significant dirt experience , and has been pointed out within this thread chopping the throttle with the rear end out can *cause* the front end to go away due to sudden and relatively speaking violent weight transfer.

Once upon a time the vast majority of us grew up in the dirt prior to getting out street license , personally I think we were all the better for it and lament the loss of the various dirt tracks and motocross tracks.


Riding in the dirt will help a great deal to mitigate the panic factor when the rear end steps out.


But what do I know I'm old and slow.




B.