How to brake discs Vs Rims

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martinn
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How to brake discs Vs Rims

Postby martinn » 24 Nov 2018, 2:19pm

Hi all,

I am wondering if there is a different method to braking with Disc brakes compared to Rim brake.
I have been riding mainly fixed for commuting, so mainly using the front brake to stop me.
I have had two offs recently on one of my two nice bikes, both on a steep downhill section, and both with unpleasant road surfaces, both on the disc braked bike.
Previously on the rim braked bike I have have never had a problem.

Now either I have just been lucky for the past 4 years or the method I ma using to brake for Rims is not suitable for discs

I currently feather the brakes, mainly using the front brake probably 90% of the time.
Being a rim brake there is a delay in the wet whilst the surface is dried.

I think I am pulling too hard on the brakes and need to use the rear brake more and not pull either one too hard.
What have others experiences been and how do you break on a steep downhill with wet leaves all over the place? (Throw in a wrong camber)

many thanks

Martin

Salty Seadog
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Re: How to brake discs Vs Rims

Postby Salty Seadog » 24 Nov 2018, 2:23pm

Modulation is the key, if you yank the front lever back to the bars you are gonna come a cropper especially on disc brakes. If you have to brake hard use plenty of rear brake a fraction before the front.
Last edited by Salty Seadog on 26 Nov 2018, 7:34am, edited 2 times in total.

Brucey
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Re: How to brake discs Vs Rims

Postby Brucey » 24 Nov 2018, 3:10pm

some brakes (be they Vees or disc brakes) often don't modulate very well and can be somewhat 'grabby'. On slippy surfaces you can lose the front quite easily with brakes like this. It helps under such conditions if the brake can be modulated easily at low-ish levels of force. Partly your troubles are surely familiarity, but some brakes just don't lend themselves to being feathered when the need arises.

If the disc brakes you have are cable discs, I'd suggest that better cables might improve the modulation. Another thing that is worth experimenting with is brake pads; change of compound and/or slight chamfers on the leading edge can make all the difference here.

If you have a powerful/grabby front brake, best use it with one finger (near the lever pivot perhaps) or avoid using it altogether if it is wet leaves you are riding on; a rear wheel skid is more easily recovered from, and if you do fall, you will be likely to fall less quickly than with a front wheel slide, giving you a split second longer to compose yourself for the inevitable....

cheers
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NATURAL ANKLING
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Re: How to brake discs Vs Rims

Postby NATURAL ANKLING » 24 Nov 2018, 3:36pm

Hi,
V's and discs cable operated, just two fingers.............if this will stop you quick in the dry good road surface then you will need no more on wet slippery stuff for sure.

I used just to use only front brake on a freewheel for years, but add hills and speed with bigger gears when I could afford such meant I used both brakes.
Its no different for motorcycles.
Come panniers and off road touring you learn quick ( motorcycles are the same but the engine if four stroke is a very good controller, without makes corners and safe braking hard work) Sooooooooooo..................haunch the saddle, keep upright, brake in straight line, out of the gutter and debris (let other users deal with themselves, stop if worried and wait for others to clear road) feather the rear brake first (trailing link front suspension scooters are the worse! back brake first or you are off) apply front as well when under control, then squeeze both but careful on the front.

As said even one finger or none up front.

No Medals for getting down first on slippery roads.

P.S. Front vs rear been discussed to death on post but when its slippery wet or dry loose its prudent to apply rear first. Only time its front for me is dismounting bike lazily.
I came to V's late in life after discs were all the rage, my first V ride nearly saw me off in the dry as previously it was Canti's.
Cheap discs cable are similar to rim with delayed braking, look further ahead and remember better to arrive safe than be late.
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fixerupper
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Re: How to brake discs Vs Rims

Postby fixerupper » 24 Nov 2018, 5:22pm

Yep that is my braking technique on bikes when I was a kid and on motor bikes as a teenager ...and now as a born again MTB cyclist with hydra lic discs. Feather the rear brake to slow and then both brakes together to stop never the front on it's own ....

pwa
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Re: How to brake discs Vs Rims

Postby pwa » 24 Nov 2018, 5:49pm

If you watch a car brake hard, as viewed from the side, you see the nose dip as the front suspension compresses. That is a downward force pressing the front tyres into the ground, giving them more grip than the rear. At that point the front wheels can usefully brake better than the rear wheels. Which is why cars often have more powerful brakes at the front.

On a bike the thing to do is apply the rear brake first to introduce deceleration, and as the deceleration produces downward pressure on the front tyre, apply more braking through the front brake. All this in a couple of seconds. Rear then front, with the front becoming dominant if hard braking is needed. And try not to get into situations where emergency braking is needed.

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531colin
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Re: How to brake discs Vs Rims

Postby 531colin » 24 Nov 2018, 6:59pm

martinn wrote:……….
I have had two offs recently on one of my two nice bikes, both on a steep downhill section, and both with unpleasant road surfaces, both on the disc braked bike...........


What happened, exactly? Lost the back? lost the front?

You can't brake hard on wet leaves and/or adverse camber. Scrub the speed off before the leaves, before the bend, and go gently on any wet leaves or adverse camber bends....no sudden changes of speed or direction. If you can, just go straight on over the leaves, and sort out speed and direction later.....but not by going on the wrong side of the road on a blind bend.
Are your tyres too hard?
Riding off-road (particularly on a rigid bike with road tyres) gives great insight into bike handling.

Ivor Tingting
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Re: How to brake discs Vs Rims

Postby Ivor Tingting » 27 Nov 2018, 7:47pm

Not enough specific information on make of brakes, cable or hydraulic, pads or blocks, rims and discs and indeed tyres. Also what ever braking system is on a bike providing you have front and rear and it is set up and working correctly, you should be able to properly modulate the braking force, front AND rear, so you don't crash. Aside from the technical specifications of the brakes it might be the incorrect use of them for the conditions? It might not be the best or indeed safest method of braking to only use the front brake 90% of the time. Maybe if the OP should use the rear brake more if he is trying to lose speed by feathering the brakes or indeed a combination of front AND rear which will make his bike better balanced and less prone to crashing? Also the type of bike tyres, road surface and weather conditions will all influence how you use the brakes and the distribution of braking between front and rear wheels. It is the friction between small patch of rubber between the tyre and the road surface that keeps you upright or lent over. If you apply sudden changes in force to this area then you can skid as the tyre loses traction. It is difficult to teach skills such as good braking on a forum when good and safe braking is the essence to riding a bicycle safely and efficiently. I have to say what ever braking system I have had on a bicycle, rim or disc brakes, I have never crashed or come off because I could not apply the brakes properly or that the brakes were defective. More generally hydraulic disc brakes are a lot more powerful than rim brakes especially in poor weather conditions where the road surface offers poor adhesion and indeed the disc brake itself acts a lot more quickly and efficiently as the disc is not very wet or covered in crud as tends to happen with rim brakes which can take an age to properly slow a bike before they bite. Maybe the OP has a cheap set of disc brakes on his bike that offer poor modulation? Sometimes changing the pads can help. Organic or metal sintered depending on the type of riding and conditions.
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hamster
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Re: How to brake discs Vs Rims

Postby hamster » 28 Nov 2018, 10:27am

My understanding is that you went over the bars...
On really steep and loose stuff offroad it's best to let the front wheel do steering and load it up with as little else as possible. Control speed with the rear. Only when the rear starts to slip should you start to use the front brake.
However a lot is also technique - make sure that you are hanging as far as possible off the back - this firstly puts more weight over the back wheel, aiding grip, and secondly puts you as far behind the front wheel stopping the rotation of body over the front...

brynpoeth
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Re: How to brake discs Vs Rims

Postby brynpoeth » 28 Nov 2018, 10:46am

Best to ride slower and use the brakes less
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martinn
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Re: How to brake discs Vs Rims

Postby martinn » 2 Dec 2018, 9:17pm

A little more info

Discs are Shimano Hydraulic using organic pads
Shop set them up, and for the first 6 months that I had the bike, including an alpine trip, the front rubbed no matter what I did to alter pads, disc or mount. I set them up, no rub then after braking rub. I had no loss of traction, but mainly in the dry.
Changed wheel, and reset no rub.
Previously only had deep drop rim brakes, and never had any loss of traction, and had ridden the same route in similar conditions, never crashed.

As to the mechanism of the incident, I "lost" the front wheel.
So after careful reflection, this is what I think happened.
I am used to Rim brakes which do take a short space of time for them to actuate, and this is what I am used to. I have probably got sloppy (as I ride fixed on my commute), and used the front brake too much, without prior incident.
Moving onto the Discs, the braking force is instant, in comparison, and much more powerful for the same amount of force applied.
Hence I lost the front wheel

So I am now trying to retrain myself to use the rear brake to slow, and pulse the front brake, in combination.

Martin

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NATURAL ANKLING
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Re: How to brake discs Vs Rims

Postby NATURAL ANKLING » 2 Dec 2018, 9:30pm

Hi,
I have never pulsed the brake on anything, got to be a bit of an old wives tale :P

Try one finger on the front then maybe two, this is what I do on two wheels when there is ice............But Back brake first.
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reohn2
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Re: How to brake discs Vs Rims

Postby reohn2 » 2 Dec 2018, 11:09pm

martinn wrote:
So I am now trying to retrain myself to use the rear brake to slow, and pulse the front brake, in combination.

Martin

That's a good braking method,pulse braking is good for bringing the speed down especially in the wet,but needs practice and a bit of finesse.
I've never ridden hydraulic discs as BB7 cable discs have always had enough power with plenty of modulation,index finger from the drops and little and third finger braking from the hoods is all that's needed.
Once you lose the front end it's rare to get it back again and usually ends up as you found,the rear is more controllable especially on longer wheelbase bikes
Organic pads have more power than sintered but not much IMO,I prefer sintered as they last longer.
Keep practicing :wink:
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NATURAL ANKLING
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Re: How to brake discs Vs Rims

Postby NATURAL ANKLING » 3 Dec 2018, 12:22am

Hi,
You will have to educate me as to what exactly pulse braking actually does?
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LittleGreyCat
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Re: How to brake discs Vs Rims

Postby LittleGreyCat » 3 Dec 2018, 5:02am

I assume this is what ABS does for you on a car - allows you to apply the brakes hard, then ease off as the wheel starts to lock so you don't skid, then repeat. Also known as cadence breaking.