Trail braking, or braking in corners.

[Screwdriver]

Wait, use the rear brake you say

Yeah...?

[MrLongbeard]

Wait, use the rear brake you say

Yeah...?

Weird man, weird.

[Screwdriver]

Wait, use the rear brake you say

Yeah...?

Weird man, weird.

Kinda silly not to....

[The Spin Doctor]

Sorry but if the tyre squidges or is rounder, there will be less offset and less tendency for counter steering which is (I suggest) the principle action here.

If it flattens out, the contact patch broadens. Think of the difference between a V and a U

If you lean the V over, the contact point ALWAYS remains the tip of the V with zero offset until you lean so far the side of the V is on the deck.

If you lean the U over, the contact patch quite clearly moves around the circular portion progressively with the offset in a direct relation to the lean angle... and so the offset INCREASES steadily with more lean.

Similarly a stiffer carcass will resist movement and maintain the maximum offset

Depends on the profile. A stiff triangular tyre will have minimal offset.

(if carcass deflection was a contributor to the effect).

And it is, according to Mr Avon.

"Explain" is perhaps too suggestive, you wanted my graphic for a book or something... It was showing why a wide tyre has a greater offset meaning the centripetal force from the cog through the tyre (lit. v.v.) could be displaced towards the contact patch, ideally right through it, if you "hang off" the bike.

I honestly don't remember that at all - as I say, the effect of the offset contact patch on steering is is a concept I've been talking about online for a couple of decades. Not to say it didn't happen but like Ronnie R. "I don't recall".

Again, I would expect a softer tyre construction would actually "smear" out the effect whereas a stiffer construction would maintain a much more tightly focussed action. Like the difference between trying to balance on a bean bag or a basketball. That would tie in with your Avon chaps description because a stiff carcass on a bumpy road would throw you all over the place since the effect is not dampened or smeared out due to contact patch compression.

Yes - as an inflated tyre behaves rather like a balloon bouncing on a surface - hit a bump, and the tyre will compress and flatten, then bounce back and regain its rounded shape. The result is that the offset changes and creates 'bump steer'. The worse the bump steer, the more smooth handling in corners is compromised.

[Screwdriver]

I think I'll just stop here because yes, if you completely change the dynamic of the situation by changing the profile of the tyre to one which does not conflict with your narrative (despite it not supporting your argument) then I am clearly not being helpful.

If on the other hand you want to go back to the scenario we were discussing earlier, you're still wrong. The bike does not stand up mid bend because of tyre deflection, it stands up because more pressure on the inside of the tyre causes countersteering. I spoke to an anonymous tyre expert earlier and he says I'm right, so I guess that cancels out your anonymous expert.

Just me and you and I am not convinced by your argument. Glad to see you picked up on my earlier explanation and present the exact scenario I just described to you back to me calling it "bump steer" which of course it is but it does that for the reasons I stated. Not yours.

[The Spin Doctor]

The bike does not stand up mid bend because of tyre deflection, it stands up because more pressure on the inside of the tyre causes countersteering.

I'm completely failing to understand why you're debating this with me. DEFLECTION in these terms can be defined as "movement or displacement of the steering mechanism" - the offset contact patch caused by the leaning tyre creates a torque on the wheel to which the tyre's fitted, turning the steering to face INTO the corner, which in consequence creates a counter-steering action which results in the bike standing up.

And as you accept that, I would have thought that it would have been obvious that the more you shift the contact patch's offset away from the centre line of the steering axis, the greater the torque - and consequently the greater the righting moment - that's created.

And if you accept that, I struggle to see how you can't also accept that the PROFILE of the tyre also matters - the rounder the profile, the more offset in the contact patch for the same angle to lean is easily demonstrated with the V and U analogy.

And if you accept that tyres DEFORM by compressing under braking forces, then it follows that the contact patch must get wider and longer. Upright, that doesn't matter, but as soon as you lean the bike over the wider element of the flattened contact patch MUST be offset further from the steering axis when compared with a tyre which retains its unloaded profile.

And that MUST make the effect of braking into a turn increase the tendency of the bike to sit up.

I spoke to an anonymous tyre expert earlier and he says I'm right, so I guess that cancels out your anonymous expert.

If I looked hard enough, I could undoubtedly find his name.

Just me and you and I am not convinced by your argument. Glad to see you picked up on my earlier explanation and present the exact scenario I just described to you back to me calling it "bump steer" which of course it is but it does that for the reasons I stated. Not yours.

I would say that I didn't "pick up on your earlier explanation" but have been saying the same thing consistently - maybe just a bit more clearly and in rather more detail.

[Screwdriver]

The bike does not stand up mid bend because of tyre deflection, it stands up because more pressure on the inside of the tyre causes countersteering.

I'm completely failing to understand why you're debating this with me. DEFLECTION in these terms can be defined as "movement or displacement of the steering mechanism" - the offset contact patch caused by the leaning tyre creates a torque on the wheel to which the tyre's fitted, turning the steering to face INTO the corner, which in consequence creates a counter-steering action which results in the bike standing up.

And as you accept that, I would have thought that it would have been obvious that the more you shift the contact patch's offset away from the centre line of the steering axis, the greater the torque - and consequently the greater the righting moment - that's created.

And if you accept that, I struggle to see how you can't also accept that the PROFILE of the tyre also matters - the rounder the profile, the more offset in the contact patch for the same angle to lean is easily demonstrated with the V and U analogy.

And if you accept that tyres DEFORM by compressing under braking forces, then it follows that the contact patch must get wider and longer. Upright, that doesn't matter, but as soon as you lean the bike over the wider element of the flattened contact patch MUST be offset further from the steering axis when compared with a tyre which retains its unloaded profile.

And that MUST make the effect of braking into a turn increase the tendency of the bike to sit up.

I spoke to an anonymous tyre expert earlier and he says I'm right, so I guess that cancels out your anonymous expert.

If I looked hard enough, I could undoubtedly find his name.

Just me and you and I am not convinced by your argument. Glad to see you picked up on my earlier explanation and present the exact scenario I just described to you back to me calling it "bump steer" which of course it is but it does that for the reasons I stated. Not yours.

I would say that I didn't "pick up on your earlier explanation" but have been saying the same thing consistently - maybe just a bit more clearly and in rather more detail.

Hang on a minute. You just spent two days arguing with me, now you are presenting the information I WROTE back to me, telling me that is correct and the single word DEFLECTION means everything I just said?

That's too much nonsense in one go. First off, I know what I said, you don't need to tell me. Secondly I know it is correct and I am surprised you've just turned this around tas if o say you knew I was correct tall along too. Finally if you knew my description was correct why did you just send two days arguing?

Anyhow, FOR THE AVOIDANCE OF DOUBT! Her is what you actually said:

But the loading on the front tyre compresses the contact patch making the bike want to sit up and go straight ahead. That's rather significant on squidgy, more rounded road tyres, less so on stiffer competition tyres. Try braking hard MID CORNER to see it in action. Just make sure you pick a bend with plenty of run-off. Braking hard on the way into the bend has the same effect, you just don't notice because it's easier to compensate by adding more steering torque.

On the road, ,ost of the 'quicker steering' effect people talk about is actually the result of the bike losing speed and turning on a progressively tighter radius as it slows down.

"Compresses the contact patch (correct) making the bike want to sit up" INCORRECT.

"Significant on squidgy more rounded tyres" INCORRECT In fact after I explain it to you you indeed agree and begin to say the exact opposite since rounder squidgy tyres actually reduce "bump steer" another name for the counter steering effect caused by contact patch offset.

I went on to say:

No, I think you misunderstand the effect of "quicker" steering, it means you can adjust your line mid bend with less steering input which places less additional load on the front tyre than a bike with less castor.

The effect you refer to when a bike wants to sit up mid bend is because loading the tyre causes the front wheel to countersteer. It is because the contact patch is offset from the centre line of the bike, on the inside of the turn. The wheel therefore steers into the bend and like kicking the bottom of a balanced pole, the top falls the other way.

I would have more respect for someone who is happy to admit they are wrong or god forbid, accept that someone else is right, than someone who argues the toss then tries to change what they said to align with the opposite of what is there for all to see.

I said I would stop. I will stop when you stop trying to rewrite history.

[Horse]

Whooopee

Another interesting thread fooked

[Wossname]

Righto. I’m going to try to return the thread to whence it came. I don’t habitually “trail brake” when I’m riding on the road, which I do fairly briskly but keeping something up my sleeve, just in case. I do wonder how much smoother/ better/quicker/(safer) a trail braker would be riding in my company. To be worth doing, I suspect they’d be closer to the limit, i.e. at greater risk, much of the time, and I’d bet they’d be very little quicker across country. In other words, it’s a track tech with little useful relevance to road riding. And yes - I’m quite happy to brake in bends, tighten lines etc when needed, but don’t use tb as routine.

There now….

[Screwdriver]

Righto. I’m going to try to return the thread to whence it came. I don’t habitually “trail brake” when I’m riding on the road, which I do fairly briskly but keeping something up my sleeve, just in case. I do wonder how much smoother/ better/quicker/(safer) a trail braker would be riding in my company. To be worth doing, I suspect they’d be closer to the limit, i.e. at greater risk, much of the time, and I’d bet they’d be very little quicker across country. In other words, it’s a track tech with little useful relevance to tias riding. And yes - I’m quite happy to brake in bends, tighten lines etc when needed, but don’t use tb as routine.

There now….

Me neither unless I am pressing on which is rare these days. Get all the braking done before the corner and tip it in as often as not with a tiny bit of throttle on to power through the bend or at the very lest not decelerate.

One of the little phrases I picked up on a rider training course (at the Nurburgring, run by coppers!) was "comfort braking". Something a LOT of us do, a LOT of the time (especially on a big fast open track). Just touch the brake for reassurance, right in the middle of a fast straight! You don't often see it of course unless you're on a track day following closely but if you're behind someone doing 120+ and they suddenly brake for no reason, it's a right pain in the arse. Not quite as bad as following a bloody Ducati which can almost do an e-stop just by rolling off the throttle...

Something I always do all of the time in traffic is ride the front brake. Two finger at all times on the front lever and in slow moving dead stopped traffic, ride the rear brake while filtering. For the road, proper use of the rear brake is a very important skill and you can show off with stoppie-uppies at the lights if you time it right.

[The Spin Doctor]

Righto. I’m going to try to return the thread to whence it came.

Fine by me.

[Horse]

One of the little phrases I picked up on a rider training course (at the Nurburgring, run by coppers!) was "comfort braking". Something a LOT of us do, a LOT of the time (especially on a big fast open track). Just touch the brake for reassurance, right in the middle of a fast straight!

Just as well I'm on ignore for never posting anything useful

(Albeit in Trinity's car thread)

One thing that has been suggested as a biking 'must' is trail braking. There's a thread here somewhere (my interpretation: a deliberate, planned, action, not to be confused with braking in bends as a necessity or 'comfort' braking).

You don't often see it of course unless you're on a track day

'Comfort' braking is common with on-road riders during cornering, usually around turn-in, for several reasons, including assessment of speed, confidence in leaning, lack of steering ability and use of the throttle.

[Dodgy69]

Shropshires rural roads don't support the art of trail braking.

[mboy]

Shropshires rural roads don't support the art of trail braking.

A very good point, and one not yet touched upon as to why generally, trail braking is not taught to road riders, and is frowned upon generally by Advanced Training providers.

I started riding on sports bikes 20+yrs ago. Trail braking works… You wanna go faster, then you need to be either on the gas or on the brakes at all times. Coasting is the enemy of a fast lap time. But to make trail braking work, you need to practice and practice being smooth with it, because as has been pointed out previously, your tyres only have a limited amount of grip, and if you’re asking too much braking grip when the tyre is already needing a lot of cornering grip, you’re gonna chuck it down the road I’m afraid… This is what causes low sides. And this is why the fastest rider of our generation, a certain Marc Marquez, bins so many bikes especially in testing… He’s not afraid to find the limit of the bike when trail braking, and then dial back a bit, where most riders don’t want to find out where the limit is at all ideally.

So as someone who had become au fait with the practice of trail braking (although staying WELL within the limits of what was possible), I was surprised to learn, given how effective it is, just how much it is frowned upon when I signed up to do my IAM advanced training… But then you start to realise that the less predictable the road surface, the more grip you need to keep in reserve, and that on the road planning ahead and reading the road conditions trumps fast track riding techniques certainly in terms of safety, and more often than not in terms of “making progress” too.

These days on the road, I rarely trail brake. Even though I’m quite happy doing it, its both rare that I’m on a road surface that really supports it, or on a bike that particularly supports it. That said… My Gasgas SM700 Supermoto kinda needs it if you want to hustle the bike. With its long travel suspension, grippy tyres and low weight, it rewards quite an active riding style and punishes an inactive one. You can’t rely on the bikes weight to provide front end grip in a corner, so you’re moving your body about a bit more and/or more typically, loading the front suspension on the brakes going into the corners and trailing the brake off to the apex more than on a bike with shorter suspension travel. Fortunately the longer travel of the Supermoto tends to mean there’s a bit more grip in reserve over the broken British B roads than there would be on a sports bike with much less suspension, and given its low weight and long wheelbase, it’s a little easier to save once either end does start to slide…

But this just reinforces precisely why it is frowned upon by training providers, as they advocate that your tyres shouldn’t be sliding at any point to be in control on the road. Hence my assertion that what is quickest on the track, and what works on the road, aren’t always the same thing. The ability to trail brake is a very useful one, but not one I suggest people rush out to practice unless they’re already totally confident on a bike that is moving about underneath them. And its certainly best practiced on a track, with a smooth and consistent surface! On the road, more important than the ability to trail brake is the knowledge of where and when you can (and should) use it, and where not to…

[mboy]

One of the little phrases I picked up on a rider training course (at the Nurburgring, run by coppers!) was "comfort braking". Something a LOT of us do, a LOT of the time (especially on a big fast open track). Just touch the brake for reassurance, right in the middle of a fast straight!

Just as well I'm on ignore for never posting anything useful

(Albeit in Trinity's car thread)

One thing that has been suggested as a biking 'must' is trail braking. There's a thread here somewhere (my interpretation: a deliberate, planned, action, not to be confused with braking in bends as a necessity or 'comfort' braking).

You don't often see it of course unless you're on a track day

'Comfort' braking is common with on-road riders during cornering, usually around turn-in, for several reasons, including assessment of speed, confidence in leaning, lack of steering ability and use of the throttle.

I know I’m having a bad day on the bike when I find myself comfort braking rather than trail braking, or not braking at all into and round the bends on the road… It happens! Knowing that you’re doing it is the first step to improving the situation though, not kidding yourself that you were actually trail braking.

[Horse]

the knowledge of where and when you can (and should) use it, and where not to…

That

[Whysub]

I seem to have done it, like Mr Cheese, from when I used to race mates on pushbike.

I have no idea, nor care, about the physics concerned, nor those that are concerned with countersteering, they just get done instinctively.

As for comfort braking, one of my police instructors said there is no such thing. "If you feel the need to lose 2 mph, you brake. Consciously trying not to brake is more of an issue".

[Screwdriver]

I seem to have done it, like Mr Cheese, from when I used to race mates on pushbike.

I have no idea, nor care, about the physics concerned, nor those that are concerned with countersteering, they just get done instinctively.

As for comfort braking, one of my police instructors said there is no such thing. "If you feel the need to lose 2 mph, you brake. Consciously trying not to brake is more of an issue".

My police instructor is better than your police instructor.

(John something iirc, only had the one arm. When he's taking you through a stupidly fast bend and you're going shit, shit, shit, he turns around to see if you're still there...)

[Whysub]

All police instructors that train riders and drivers are better than their students....

[Screwdriver]

All police instructors that train riders and drivers are better than their students....

I'm tongue in cheek of course but the above is a true story. It was twenty years ago (!) but iirc it was some sort of rider training thing being run by da police and they booked out the Numburgring, bikes only, for 2-3 days. Pretty amazing experience and at the end a competition to see who was the best rider around the ring.

Obviously they didn't let any of the coppers enter, they were all dotted around the trackside judging lines etc. Not all of them were what you might call super fast riders/racers but man they were smooth...