The friendly "dumb" bike questions thread

The friendly "dumb" bike questions thread

Author
Discussion

CousinDupree

779 posts

66 months

Wednesday 6th March 2019
quotequote all
Zarco said:
I've done the shuffle a few times! I was taught to cover the rear brake at a stand still. Think I was also taught to change down to 1st and hold the clutch in too (or that's what I generally do anyway). The shuffle only becomes a requirement if I've cocked up and stopped in second, or want to knock it into neutral.

Interestingly since getting the bike out this year, I've found myself not religiously covering the rear brake at lights and junctions. Am I getting more advanced?l
Lol, you've just applied common sense and use the rear brake to hold the bike at a standstill when it's needed smile

It's like they don't teach you to always reverse the bike into a downhill space. You only make that mistake once though.

black-k1

11,889 posts

228 months

Wednesday 6th March 2019
quotequote all
cbmotorsport said:
tvrolet said:
cbmotorsport said:
black-k1 said:
anonymous said:
[redacted]
nono

Not good! Rear should be used in all road circumstances.
With respect, and not being arsey, everyone has different styles and different ways of riding a bike. What one should and shouldn't do is entirely up to them. :-)

If I'm ever braking hard enough on the road to need my rear brake as well as the front, the amount of weight over the rear wheel is going to render the rear brake pretty useless anyway, as the front suspension is compressed and the weight is very much over the front.
Yea, but until the point you're doing a stoppie and the rear wheel is actually off the ground then there is at least some weight on the rear wheel, and so it can contribute to the stopping effort. But also, if you aren't doing a stoppie then there's momentum in the rear wheel rotating (and unless you've pulled the clutch the motor is also turning the rear wheel) so rear brake also negates these effects. But yes, if the rear wheel is off the ground the rear brake wont contribute anything at that point.

So everyone who can stop from the speed they're going to a halt with the rear wheel off the ground or just kissing the tarmac the whole time will not stop any quicker by using the rear brake. But for everyone else...

Yes the rear brake contribution is bike dependent - my bikes are all long wheelbase and heavy, and so the rear brake alone offers significant stopping power, and none of them are going to get anywhere near a stoppie so the rear brake will always contribute to the stopping. But even on a short wheelbase bike, unless the rear wheel is actually off the ground then there's additional stopping power available from the rear. And (bike dependent of course) you can often over-estimate just how much of the weight has transferred to the front, especially with long-travel suspension and assume there's no weight left on the rear while actually there is.
Not really talking about stoppies, just unweighting the rear through hard braking. You'd have to have a very deft touch not to lock up the rear if you're using a lot of front brake as lack of weight on the rear tyre means less friction.

All your points taken though.
For 9 out of 10 times, especially on a bike with a short wheelbase (sports bikes), use of the rear brake is irrelevant but for 1 in 10 times it could just be the difference between continuing your ride on a bike or continuing your ride in am ambulance.

We train ourselves to do things and to react in specific ways to ensure that when an unexpected, unplanned event occurs, we react correctly. An unexpected braking requirement is likely to require that the maximum amount of speed loss is achieved in the shortest possible time. Because the event is unplanned and unexpected, your mind is likely to be focussing on something other than the correct use of the brakes. If your instincts are not trained correctly to use the rea brake, you won't use it.

The extra stopping distance required through not using the rear brake, especially if the road surface is less than perfect, could very well be the difference between something and nothing.

Someone at Aprillia did a scientific paper covering this which may (or may not!!!) be interesting reading:

On optimal motorcycle braking

Matteo Cornoa , Sergio Matteo Savaresia,, Mara Tanellia , Luca Fabbrib

a Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milano, Italy b Piaggio Group—Aprilia Brand, Via Galileo Galilei, 1, 30033 Noale, Venice, Italy

Received 21 March 2007; accepted 1 August 2007 Available online 21 September 2007

http://www.elsevierscitech.com/pdfs/CEP_Corno.pdf

I will admit I’ve not read the entire paper but did read some interesting details in section 3. The paragraph of interest says:

This section is concluded by observing that in the long 300-80 km/h braking maneuver, the difference of performance is very large, about 300 ms. This difference is largely due to the fact that the ‘‘traction’’ torque has been replaced by a ‘‘braking’’ torque at the rear wheel Although the braking torque at the rear wheel is rather small compared to the front-wheel one, on a strong braking maneuver the effect of the rear brake can be clearly appreciated. This is true, in particular, if the front-brake controller is able to maintain a small but non-zero load on the rear tire.

Note: My bold

I've issued this challenge a number of times on this forum and as far as I know, only Dern has been brave enough to actually try it and report back:

Find a quiet straight bit of road with a fixed point as a braking marker. Approach the point a a set speed (above 30mph) and brake, rear only) from that point. Note where you come to a stop.

Repeat the test, same speed, same braking point, this time front only. Again note where you come to a stop.

Do a final run, same speed, same point but this time use both front and rear brakes together, and note where you stop.

If you feel brave or are not yet convinced, do the same thing again in wet conditions.

Report back here with the results.



Edited by black-k1 on Wednesday 6th March 15:11

RizzoTheRat

25,085 posts

191 months

Wednesday 6th March 2019
quotequote all
tvrolet said:
But also, if you aren't doing a stoppie then there's momentum in the rear wheel rotating (and unless you've pulled the clutch the motor is also turning the rear wheel)
Surely until you get down to pretty low speeds engine braking should be ensuring the rear wheels dragging not powering even if you're not on the brake?

On my 900 twin I've got enough engine braking that I can slide the rear if I change down at too high revs biggrin



black-k1 said:
Find a quiet straight bit of road with a fixed point as a braking marker. Approach the point a a set speed (above 30mph) and brake, rear only) from that point. Note where you come to a stop.

Repeat the test, same speed, same braking point, this time front only. Again note where you come to a stop.

Do a final run, same speed, same point but this time use both front and rear brakes together, and note where you stop.
Only time I've ever actually seen this done was my CBT instructor on a CG125, and it made a reasonable difference.



julian64

14,317 posts

253 months

Wednesday 6th March 2019
quotequote all
Catnapper said:
Zarco said:
What about counter steering? Does it exist?













Just thought I'd throw that in there

getmecoat
rofl
Sorry missed this. No counter steering doesn't exist. Never used it never will use it.
possibly at some fundamentally useless physical level its part of the actual mechanism but nothing you have to consciously do.

In other words people who say to turn left you need to give a good yank on the right bar to pull the bike down are idiots IMHO.

dern

14,055 posts

278 months

Wednesday 6th March 2019
quotequote all
black-k1 said:
I've issued this challenge a number of times on this forum and as far as I know, only Dern has been brave enough to actually try it and report back:
Can confirm and it changed my braking style.

cbmotorsport

3,065 posts

117 months

Wednesday 6th March 2019
quotequote all
julian64 said:
Catnapper said:
Zarco said:
What about counter steering? Does it exist?













Just thought I'd throw that in there

getmecoat
rofl
Sorry missed this. No counter steering doesn't exist. Never used it never will use it.
possibly at some fundamentally useless physical level its part of the actual mechanism but nothing you have to consciously do.

In other words people who say to turn left you need to give a good yank on the right bar to pull the bike down are idiots IMHO.
It's just a name for the mechanics of making a bike turn at anything other than walking pace.

Krikkit

26,500 posts

180 months

Wednesday 6th March 2019
quotequote all
What happened to this thread? It ended up like a flat earth bike conspiracy thread. Rear brakes work, counter steering is an essential part of turning. Easy.

tongue out

Biker's Nemesis

38,536 posts

207 months

Wednesday 6th March 2019
quotequote all
black-k1 said:
I've issued this challenge a number of times on this forum and as far as I know, only Dern has been brave enough to actually try it and report back:
It only works on my Fizzy and RD 125



Biker's Nemesis

38,536 posts

207 months

Wednesday 6th March 2019
quotequote all
For fks sake, no one mention SHARP.

black-k1

11,889 posts

228 months

Thursday 7th March 2019
quotequote all
Biker's Nemesis said:
black-k1 said:
I've issued this challenge a number of times on this forum and as far as I know, only Dern has been brave enough to actually try it and report back:
It only works on my Fizzy and RD 125
On a damp or less than perfect surface? Really?

black-k1

11,889 posts

228 months

Thursday 7th March 2019
quotequote all
Biker's Nemesis said:
For fks sake, no one mention SHARP.
Now that you've mentioned it ... biggrin

Anyone for a POLITE vest?

TooLateForAName

4,727 posts

183 months

Thursday 7th March 2019
quotequote all
julian64 said:
Sorry missed this. No counter steering doesn't exist. Never used it never will use it.
possibly at some fundamentally useless physical level its part of the actual mechanism but nothing you have to consciously do.

In other words people who say to turn left you need to give a good yank on the right bar to pull the bike down are idiots IMHO.
Oh dear.

I really struggle to go around corners without countersteering. Certainly there is no way I'd have got through the mod1 avoidance test without deliberate countersteer.

I accept that there is a lot of total bks spouted about it, but its real.

A bike is inherantly stable and will try to move in a straight line and stay upright. If you want to turn you need to apply a force sideways. The way you do this is to move the point of contact with the road to the opposite side of the bike.

RizzoTheRat

25,085 posts

191 months

Thursday 7th March 2019
quotequote all
black-k1 said:
Now that you've mentioned it ... biggrin

Anyone for a POLITE vest?
Loads of people wearing them around here hehe




Edited by RizzoTheRat on Thursday 7th March 09:05

Biker's Nemesis

38,536 posts

207 months

Thursday 7th March 2019
quotequote all
Now you've done it ^^^^^

dern

14,055 posts

278 months

Thursday 7th March 2019
quotequote all
black-k1 said:
Biker's Nemesis said:
black-k1 said:
I've issued this challenge a number of times on this forum and as far as I know, only Dern has been brave enough to actually try it and report back:
It only works on my Fizzy and RD 125
On a damp or less than perfect surface? Really?

cbmotorsport

3,065 posts

117 months

Thursday 7th March 2019
quotequote all
What tyres does everyone recommend??












getmecoat

cbmotorsport

3,065 posts

117 months

Thursday 7th March 2019
quotequote all
anonymous said:
[redacted]
It was a gag toxic, possibly not the best one. I was just adding another opinion splitting question to the list above. :-)

cbmotorsport

3,065 posts

117 months

Thursday 7th March 2019
quotequote all
anonymous said:
[redacted]
Thanks for your efforts though!

tvrolet

4,251 posts

281 months

Thursday 7th March 2019
quotequote all
cbmotorsport said:
What tyres does everyone recommend??
Whitewalls, obviously.

Mr Dendrite

2,301 posts

209 months

Thursday 7th March 2019
quotequote all
tvrolet said:
cbmotorsport said:
What tyres does everyone recommend??
Whitewalls, obviously.
Only Fettuccini will do smile