Motorbike disc brakes are good or bad, light or heavy, have good or poor feel, work well from cold or need to warm up but nowhere are they modulated.

So what is it – enlighten me

Essentially control, how much control you have over the available power.

yep. so basically a brake you can lock dead easily won’t have as good a modulation as one that’s harder to lock, as there’s less ‘range of pressures’ you can apply to the brake lever..

brakes that have no modulation would be on or off.

yep. so basically a brake you can lock dead easily won’t have as good a modulation as one that’s harder to lock, as there’s less ‘range of pressures’ you can apply to the brake lever.

I want a brake I can lock easily but one that also has good feel and little lever travel from full on to to full off.

So do I need good or badly modulated brakes?

I don’t think any manufacturer would advertise their brakes as having no modulation, if it helps my Avid Elixir’s have loads more modulation than my old Hayes nines but i can lock them up with ease if i choose to, the modulation means that i can choose not to lock up and slow down under control. My old Hayes had me off a few times due to there on/off feel.

Modulation is generally considered a good thing, the amount of power will depend on the intended application of the brake.

In my experience, Avid modulate better than Hayes but Hope modulate better than Avid.

I like what everyone else calls badly modulated brakes, they go to full blast in a very small lever travel. I find I can control (modulate) the brake force very easily and accurately over this small range.. So poor modulation is essentially a subjective thing.

I would describe “feel” and “modulation” as one and the same in this case. If you can feel what the brake is doing then you can easily modulate it.

Motorbike disc brakes are good or bad, light or heavy, have good or poor feel, work well from cold or need to warm up but nowhere are they modulated.

Ohh yes they are!

Good feel = Easy to modulate

Just found this:

http://www.simkinsdesigns.com/modulation.htm

However, I think that over-simplifies things – you can have excellent feel within short travel on the lever, just as you can have rubbish feel over a middling travel range. The greater the losses in the system (particularly noticeable with cable rear brakes) the worse the feel tends to be – you want to feel the opposing force to that of the pad on disc, you don’t want to feel the friction in the cylinder or give in the brake lines.

A lot of car brakes have poor feel (particularly at lower speeds due to excessive servo assistance) and just rely on ABS to modulate the brakes for you at the limit. Carbon ceramic racing discs tend to have poor feel at lower temperatures but then very good feel once the discs are hot (by which point a steel disc would be starting to fade), because at lower temperatures the coefficient of friction between pad and disc is too low.

Does disc size make any difference? Will I have less modulation with a bigger disc?

….and here is a brake that’s a bit wooden.

Motorbike disc brakes are good or bad, light or heavy, have good or poor feel, work well from cold or need to warm up but nowhere are they modulated.

Ohh yes they are!

That’s how a mountain biker might might describe them but I have never once seen a motorbike road bike test that uses the word “modulation” to describe how a brake performs or feels and in the real motorbiking world I have never talked to anyone who “modulates” their brakes.

I have never talked to anyone who “modulates” their brakes

they must use another term then?

I think there is an over simplification in this thread and in the linked article about lever throw and modulation. It’s about feedback.

Hayes hfx 9 had enough leverthrow but the difference in feel between a bit on and lots on was not much – they had little modulation.

XT servowave can be set up with little lever throw but have loads of modulation.

The bigger the disc the less force you will need to apply at the lever to get it to work. So with less power applied you can feel it more, or apply steadily incresing power up to the point at which the wheels start to lock – then let off.

If you have a big disc you can use just one finger, this makes a bid difference to a ham fisted handfull for sensitive braking on slippery surfaces.

For me modulation is in your finger, not the brake. My LBS told me my Saints were overkill on my XC bike – in practice they allow one finger control which means very very sensitive braking and loads of power if needed. Much better than very small discs.

Pretty much any appropriate brake will generate enough power with one or two fingers to lock the wheels with more or less lever movement. What is IMO more important is to be able to “feel” what the brake is doing so you can continually make small adjustments to the braking force to slow you down as much as you need without locking the wheel up.

I like what everyone else calls badly modulated brakes, they go to full blast in a very small lever travel. I find I can control (modulate) the brake force very easily and accurately over this small range.. So poor modulation is essentially a subjective thing.

I dont think this is completely true I thought it was with V-Brakes but I suppose that because they are not as powerful as disc.

I generally like very small lever travel as you say, but when I had avid BB7s I set up the brakes for small lever travel. They became very grabby. ( I could also spin the speed-dial but they felt mushy then and this didnt always help)

This was never a problem on the front as most of the time I wanted to brake I had plenty of weight on the front.

But if I did not have much weight on the rear wheel I’d find sometimes it would lock it up no matter how gentle I was with the lever. Like the minimum power that could be applied was more than traction the wheel could have (mainly on sandy/slippy descents).

I now have avid juicies and if they are well bleed and the pads are close they can have very small travel on the lever. But I never accidently lock the rear wheel. Presumably because they are easier to modulate.

To be pedantic about lever travel…
Lever travel is just to take up the gap between the pads and the disc.
Once the pads are in contact, it’s lever pressure that modulates the brake force.

Otherwise, I’d agree with most of the above.
If you can control a brake so the wheel is just on the point of locking up on a loose surface or do stoppies, that’s good modulation.

Feedback is the key then – modulating then is just adjusting to the feel you get to avoid a spill.

More feel is also down to tyre/ground friction and pad/disc friction, not just your sticky pistons that have crap seals and decade old brake fluid with expanding brake hoses.

There is a lot involved here with a simple marketing term called Modulation then.

What is IMO more important is to be able to “feel” what the brake is doing so you can continually make small adjustments to the braking force to slow you down as much as you need without locking the wheel up.

Indeed – ABS for bikes. All that’s needed is some brakes that are not too snatchy and some sensitive fingers!

Modulation is down to the rider – it’s just how sensitive you are to your pressure on the lever, or if you mistake lever travel for brake force and assume that the same travel should give the same force on all brakes. If you’re club fisted you’ll find some brakes hard to modulate.

coffeeking – Member
Modulation is down to the rider – it’s just how sensitive you are to your pressure on the lever, or if you mistake lever travel for brake force and assume that the same travel should give the same force on all brakes. If you’re club fisted you’ll find some brakes hard to modulate.

I think coffeeking talks sense.

If modulation is anything (and not just marketing BS) it’s to do with your ability to sense when the wheel is going to lock/skid and adjust the lever pressure accordingly.

So, in conclusion then, stick a finger up to marketing speak about modulation. Use that same finger to “modulate” your braking.

Right, bring on the next marketing bollocks and we will talk it into sense.

Trimix – Member
So, in conclusion then, stick a finger up to marketing speak about modulation. Use that same finger to “modulate” your braking.

Right, bring on the next marketing bollocks and we will talk it into sense.

Perfectly summed up thread closed 🙂