Oversteer... The cure for understeer?

[Bluenote]

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.

The paragraph I highlighted within the above is *exactly* correct.


And while we all ride bikes here , lets examine car dynamics for a moment , the vast majority of street cars are set up to *understeer* , meaning that they will almost inevitably PLOW first on neutral throttle or off throttle , when this happens it *can* be saved by judicious application of the throttle and bringing the rear end out , this will accomplish the effect of arresting the plow towards the outside of the corner and will tighten the line.

Same thing with a bike.


And motorcycles are a vehicle that inherently wish to be cornered with the throttle ON , running into a given corner with the throttle OFF and coasting through is inviting a disastrous front end slide that may well be unrecoverable dependent upon how close to the limits of traction you are already.

Me personally? I have no wish to bin it , that said I'd a hell of a lot rather lowside than get spit off the high side.


Here's another caveat however as regards modern sportbikes , most have very limited steering lock when compared to dirt bikes.


And I'll tell you that it's an immensely satisfying feeling in the dirt to stuff it in , come into the throttle and hang the rear wwwayyyyyyy out all around the radius of a given corner , you can adjust your line quite literally "steering with the throttle".

And keep in mind that *powerband* and how a given scoot *makes* it's power can have a limiting effect on this , I'm sure we've all seen this syndrome in reference to certain modern sportbikes with a relatively large spike of power , you're fine if you come in on the powerband , it's when you're under said powerband , come into it and are already close to raction limits and hit that 20-30 horsepower jump in power across 1500 rpm or so and it spins up so quickly that the rear jumps out so far so fast that it promotes the aforementioned *panic reaction* and the rider snaps the throttle closed.

This is one thing that makes scoots like the 650 Hawk and the SV650 so ridable as compared to some I4s , same with other twins and a great many singles.

As a perhaps glaring example refer back to the TZ700 miler that K.R. won back to back Indy miles on 'lo thoses many years ago , when a rider of that caliber makes the statement that the bike was damn near unridable due not to the power level it made but the WAY it made power , pay attention.

BAck to cars , as I said in a different thread I once worked for Garretson enterprises , I well remember when the 930s ( Turbo Carrera) first hit the states and how many of 'em came in crunched due to exactly that factor ,that 150 horsepower jump when the boost came up mid corner caused a lot of panic reactions that had people lifting at EXACTLY the wrong time and spinning 'em backwards into solid objects , this of course being exacerbated by all that weight hanging out behind the rear axle. Any given rear engined Porsche needs to be cornered with the power ON. Perhaps that's a rather extreme example , but isn't it rather apropos to this discussion?



B.

 

[JeffKoch]

And motorcycles are a vehicle that inherently wish to be cornered with the throttle ON , running into a given corner with the throttle OFF and coasting through is inviting a disastrous front end slide that may well be unrecoverable dependent upon how close to the limits of traction you are already.

That seems an overstatement, it really depends on the bike, tires, geometry, road surface relative to gravity, what you're trying to accomplish, etc.

...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.

Can you imagine a scenario where this might actually happen? I'm having hard time imagining one.

 

[Bluenote]

That seems an overstatement, it really depends on the bike, tires, geometry, road surface relative to gravity, what you're trying to accomplish, etc.



Can you imagine a scenario where this might actually happen? I'm having hard time imagining one.

*might* be an overstatement Jeff , but It's been my experience that the vast majority of bikes prefer to be cornered at neutral or positive throttle. Same with most performance cars that I have personal experience with.Your mileage may vary on this and it likely varies to some degree with suspension setup.


In the second case , shortly before I moved up here I had it happen to a kid on an R6 right directly before my eyes on 9 , by rights I guess he should have highsided but when he came out of the throttle ( and I could tell 'cause he had the loudest damn pipe in the known world) he lost the front end , granted it was downhill and slightly off camber but it did happen. Heck of it is we weren't going all that quickly and I'll grant that it may well have been exacerbated by the fact that he seemed to be more worried about us behind him than what was in front of him. And I've had it happen to *me* in the dirt.


I'd be interested in your further opinion on this. Seriously.



B.

 

[Burning1]

One or two other observations:

1. It's critically important to relax when things start sliding. If the rear end steps out and the arms are locked on the bars, the front wheel won't be free to turn into the slide. The end result will be a high-slide.

2. If you are counter-steering into the corner and the rear end starts to step out, you may need to keep steering in order to point the front tire forward. The good news is that counter steering and over-steer management both require the rider to turn the bars in the same direction.

 

[Bluenote]

One or two other observations:

1. It's critically important to relax when things start sliding. If the rear end steps out and the arms are locked on the bars, the front wheel won't be free to turn into the slide. The end result will be a high-slide.

2. If you are counter-steering into the corner and the rear end starts to step out, you may need to keep steering in order to point the front tire forward. The good news is that counter steering and over-steer management both require the rider to turn the bars in the same direction.

Completely correct on both counts. You best not call yourself a "novice powerslider" again or we'll collectively beat you with a worn-out 70s era wet and stinky Dunlop K-70.....(chuckle)


By the way how do like that Rockster?



B.

 

[JeffKoch]

I can imagine loosing the front after getting completely sideways and chopping the throttle, but I think in pretty much every case it's because the rider made a mistake in steering the bars (locking his arms in a death grip, for example), and not because the front tire was "overloaded", which is really hard to do. If you're that close to overloading the front tire, you're at an extreme lean angle where a rear-end slide will cause an instant lowside - this critical lean angle might decrease on wet pavement, for example, but in that case the rear end tends to slip and just keep going, again causing a lowside from the rear. Point is, if you're in a situation where a weight transfer will (by itself) cause a lowside from a front tire tuck, you're probably going to lowside from the back letting go long before you have to worry about the front.

A recent personal observation: I made an error at a track day in October at Thill going through T13, WFO on relatively cold tires, and hung the rear waaaaay out to the right. I was certain I was toast and was just waiting to get launched, but my instant reaction saved me - roll off the gas *slightly* to keep the rear from continuing to slide sideways, and stay loose on the bars. It was a wild ride, with the rear end flapping and the front end tankslapping, and I'm sure at some point that I must have cut the throttle just because I couldn't possibly maintain that kind of fine control in the situation, but it worked out fine and I stayed upright. I'm quite sure that continuing to maintain a WFO throttle would have caused a lowside, that chopping the throttle would have caused a highside, and that holding a death grip on the bars would have also resulted in a crash.

 

[Bluenote]

I can imagine loosing the front after getting completely sideways and chopping the throttle, but I think in pretty much every case it's because the rider made a mistake in steering the bars (locking his arms in a death grip, for example), and not because the front tire was "overloaded", which is really hard to do. If you're that close to overloading the front tire, you're at an extreme lean angle where a rear-end slide will cause an instant lowside - this critical lean angle might decrease on wet pavement, for example, but in that case the rear end tends to slip and just keep going, again causing a lowside from the rear. Point is, if you're in a situation where a weight transfer will (by itself) cause a lowside from a front tire tuck, you're probably going to lowside from the back letting go long before you have to worry about the front.

A recent personal observation: I made an error at a track day in October at Thill going through T13, WFO on relatively cold tires, and hung the rear waaaaay out to the right. I was certain I was toast and was just waiting to get launched, but my instant reaction saved me - roll off the gas *slightly* to keep the rear from continuing to slide sideways, and stay loose on the bars. It was a wild ride, with the rear end flapping and the front end tankslapping, and I'm sure at some point that I must have cut the throttle just because I couldn't possibly maintain that kind of fine control in the situation, but it worked out fine and I stayed upright. I'm quite sure that continuing to maintain a WFO throttle would have caused a lowside, that chopping the throttle would have caused a highside, and that holding a death grip on the bars would have also resulted in a crash.

I agree with just about everything you stated above Jeff , that said I'd bet that you were fairly neutral with the throttle or came out of it gently , you may well have a very good point as regards "tightening up" the rider I used as an example may have well been frozen rigid , but the front end went first but the as I said that may have been exacerbated by the downhill and off camber factor.

And I'll freely give you that it's not a simplistic one size fits all question , and Burning brought up the good point about relaxation , I'm pretty relaxed on a bike even with the rear end out , losing the front end on the other hand will certainly cause me to puckerup and grip the seat with things that don't ordinarily clench ( so to speak) and my prefered method of cornering a dirt bike or my D/P on loose surfaces is sliding it flat-track style , which is one reason I never got along with Huskies in the old days that well , they liked the square it off and bang the berm method , Bultacos could be slid for days and Maicos did whatever you wanted.

Maybe to a degree it's what a given individual is comfortable with? In the example that you cite at THill it sounds like that though you may well have been apprehensive you didn't "panic" and were to some degree "comfortable" enough to do exactly the right thing.

I've often wondered how many folks have been killed/hurt by panicing at exactly the wrong moment?


BAck to the weight transfer thing , if you've got the rear out and spinning is it still taking a significant amount of weight of the front? the corollary question being that if you've got it over enough to prevent a highside when you come out of the throttle would it transfer enough weight back to the front to degrade available traction? And how would individual suspension setups affect this?


I'm tempted to take the DR out to a convenient sandwash I know of up here and experiment a little tomorrow ( barring rain) but I don't want to fuxor my old bones up too much more , I walk like a stepped on cockroach as it is.

Maybe I'll borrow a buddy of mines XR100 , but how much validity would conclusions on it's behavior lend to a sportbike? If nothing else I can have an excuse to get out on it an play " imitation Miler".


Interesting discussion.



B.

 

[Gary J]

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.

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

The following is in reference to a VERY advanced technique Chris (so please take this for what it's worth, and only for those that are truly experienced enough to consider it), but to answer your question ...... "YES", the use of deliberately induced rear wheel traction loss (oversteer) is a viable approach (in certain conditions) to reduce/eliminate "understeer" (and possible front end traction loss).

When? For me, the most applicable (to this forum discussion) is when I'm riding a sportbike ...... in "semi-spirited" fashion ..... on wet/rainy pavement.

My philosophy (a technique tested and proven) is that IF the rear tire is doing the lion's share of the work (as a result of the rider's throttle inputs), while finishing off a corner, the probability of the front tire's adhesion limit being exceeded, and losing grip, is greatly reduced!

As such, the technique I use in the rain, is to very deliberately apply enough throttle while finishing off the last 1/3 (or so) of a turn, to break a full 1-to-1 level of traction with the rear tire and the pavement.

As the rear tire breaks grip, in a rider-metered (by throttle control) fashion, the lateral (to the outside of the turn) cornering forces will gradually bring the rear of the bike around a bit, pivoting the bike's chassis around the contact patch of the front tire.

The result (objective) being the front end of the bike pointing more in line with the desired path for exiting the turn. Basically a deliberately induced, throttle driven, "oversteer" (as you noted).

The bike is gradually straightened up (off an already minimized amount of lean angle in these conditions), in sync with the gradually increased amount of throttle-induced rear tire slippage ..... while finishing off the corner.

It works incredibly well in these conditions, and enables for consistently taking turns at speeds that many would believe to be impossible (and/or "crazy") ....... on wet, slippery pavement (only at the track, of course )

Confirmation that the technique is having the desired impact, comes in the form of tire mileage/wear rates.

In the dry months, the front AND rear tires on the Ninja 250 wear at about the same rate, living for about 4K+ miles before needing replacement.

In the rainy season, the front wear rate is similar, but the rear tire is often down to the wear-bars within 2,500 miles! Why? The regular conscious throttle-induced "breaking traction" (hence wet-sanding the tread surface of the tire), done for the purpose of deliberately producing desired "oversteer", in the above-described conditions.

So again to answer your question Chris, "YES", using a very precise level of deliberate throttle induced "oversteer" with the rear, can most certainly result in eliminating a potential "understeer" (or losing the front tire's grip, in the instance of this wet-pavement scenario).

Hope that gives you some support to your new found bike control behavior, Chris.

 

[Bluenote]

The following is in reference to a VERY advanced technique Chris (so please take this for what it's worth, and only for those that are truly experienced enough to consider it), but to answer your question ...... "YES", the use of deliberately induced rear wheel traction loss (oversteer) is a viable approach (in certain conditions) to reduce/eliminate "understeer" (and possible front end traction loss).

When? For me, the most applicable (to this forum discussion) is when I'm riding a sportbike ...... in "semi-spirited" fashion ..... on a wet/rainy pavement.

My philosophy (a technique tested and proven) is that IF the rear tire is doing the lion's share of the work (as a result of the rider's throttle inputs), while finishing off a corner, the probability of the front tire's adhesion limit being exceeded, and losing grip, is greatly reduced!

As such, the technique I use in the rain, is to very deliberately apply enough throttle while finishing off the last 1/3 (or so) of a turn, to break a full 1-to-1 level of traction with the rear tire and the pavement.

As the rear tire breaks grip, in a rider-metered (by throttle control) fashion, the outside directing lateral cornering forces will gradually bring the rear of the bike around a bit, pivoting around the contact patch of the front tire ... and pointing the front end of the bike more in liine with the desired path for finishing off the turn. Basically a deliberately induced, throttle driven, "oversteer" (as you noted).

It works incredibly well in these conditions, and enables for consistently taking turns at speeds that many would believe to be impossible (and/or "crazy") ....... on wet, slippery pavement (only at the track, of course )

Confirmation that the technique is having the desired impact, comes in the form of tire mileage/wear rates.

In the dry months, the front AND rear tires on the Ninja 250 wear at about the same rate, living for about 4K+ miles before needing replacement.

In the rainy season, the front wear rate is similar, but the rear tire is often down to the wear-bars within 2,500 miles! Why? The regular conscious throttle-induced "breaking traction" (hence wet-sanding the tread surface of the tire), done for the purpose of deliberately producing desired "oversteer", in the above-described conditions.

So again to answer your question Chris, "YES", using a very precise level of deliberate throttle induced "oversteer" with the rear, can most certainly result in eliminating a potential "understeer" (or losing the front tire's grip, in the instance of this wet-pavement scenario).

Hope that gives you some support to your new found bike control behavior, Chris.

" Squaring off" the corner as it were Gary? And thanks for weighing in on this.


Now does the same scenario apply in the dry? It has always seemed to me to be so , but Jeff got me cogitating on it , he seemed make some good points.

That said I was able to at times do what you described on the Aprilia coming off certain corners , but wonder if it contributed to the lessening of any understeer? And would closure of the throttle in too sudden a manner contribute to weight transfer that might engender a possible loss of traction at the front?




B.


B.

 

[Yody]

Everyone in this thread other than Gary J needs to stop trippin so much and take it easy while riding in the rain unless you're on a motard

 

[Gary J]

" Squaring off" the corner as it were Gary

A very delicate (and skill-required) operation on pavement, on a sportbike (compared to the motocross version) ..... but YEP .... "Squaring Off" is the basic nature of what's being done.

Now does the same scenario apply in the dry?

On the racetrack, when pushing for race-pace ...... especially on a powerful literbike ....... "YES". Under most other conditions (especially the street), I'd say "NO", and discourage any actions in deliberately trying to break rear wheel traction (for steering impact).

would closure of the throttle in too sudden a manner contribute to weight transfer that might engender a possible loss of traction at the front?

Absolutely!

This very advanced technique (for the specialized conditions ONLY) for throttle-induced rear wheel "steering" effect, NEVER consists of getting back out of the throttle (especially suddenly!) ...... once the very controlled level of throttle increase (to just exceed the traction threshold of the rear tire) has been started. This throttle application level is maintained right through the point of finishing off the turn, and getting the bike back up in a totally straight up-n-down condition, as it exits the corner.

A fine "feel" for traction is required for metering in this throttle application, at the precise rate needed to achieve a level of load/force that's just one-notch past the traction threshold level of the rear tire.

Definitely NOT a technique to be applied by novice riders!!!

Hope this is of some help in response to your questions Bluenote.

 

[Gary J]

Everyone in this thread other than Gary J needs to stop trippin so much and take it easy while riding in the rain unless you're on a motard

Hey Yody, don't you know that Ninja 250's eat "Motards" for lunch ....... in the rain!

 

[Bluenote]

Everyone in this thread other than Gary J needs to stop trippin so much and take it easy while riding in the rain unless you're on a motard

Hey come on now Yody , sliding around in the rain can be a great deal of fun , but then it's all fun until someone gets a sharp stick in the eye 'eh (chuckle)..

And my DR 650 is a ball in the wet. ( did I say that out loud?) ahem , For off road use only ...heheh.



B.

 

[JeffKoch]

Maybe I'll borrow a buddy of mines XR100...

Yup, that's the kind of machine you want to ride if you want to play with this stuff. Riding a small bike on dirt, you can learn a lot about throttle control, slides, and Gary's suggestion about squaring off corners in the rain, which is a technique that probably only Gary can pull off successfully without wading his bike.

 

[Bluenote]

Yup, that's the kind of machine you want to ride if you want to play with this stuff. Riding a small bike on dirt, you can learn a lot about throttle control, slides, and Gary's suggestion about squaring off corners in the rain, which is a technique that probably only Gary can pull off successfully without wading his bike.

Nah I do a lot of sliding around on fire-roads and the dirts roads up here in the north end of the state at speeds between 20-65 or so on my Dr , I was refering to the XR100 because if I'm going to deliberately turn the throttle off to see if the front end goes away I want to be going a lot slower and a 150 lb bike doesn't drill you into the ground NEARLY as hard as a 340 or so lb bike does.


But yeah a small bike in the mud is actually the best way to experiment with such things. And loads of fun.

B.