V Brakes braking with load

[JohnInStockie]

Hi Guys

just wondering if it was me, but yesterday I was riding home with panniers in the wet, one pannier heavier than the other. I applied my rear brake which seemed at first not to slow me down and then suddenly locked, and the whole bike skidded to one side !!!

Is that normal? Would it be the panniers causing that or something with the brakes themselves?

Thanks

John

 

[flecc]

A heavy load on one side can determine which way the bike slides John, but a rear wheel's sudden loss of adhesion in the wet is common, especially where the odd oil or diesel spill patch occurs.
.

 

[essexman]

I skidded for the first time in my agattu today, had to overshoot a junction before i gained control, very scary.... I was going downhill and just couldnt get the skid stabilised enough to start breaking.

Any tips for regaining control on a skid when going downhill?

I was in a bad braking position i hadnt shifted my weight backwards at all, let alone attempted to get out of the seat

 

[Lloyd_50cycles]

When braking under load you should ideally use mainly the front brake 70% front, 30% rear. This is because the front wheel has more weight behind it so will be less likely to lock. If you lock the rear wheel, shift you weight further back, release the lever(quite difficult to do as it goes against all insincts, especially if approaching something!) and re-apply progressively. By that I mean gradually increase pressure, don't just yam it on. Only brake when the bike is upright, you have more tyre in contact with the ground, therefor more grip. Don't brake in a corner, always brake before(again less grip whilst cornering and more likely to skid). Always apply more pressure to the front brake than the rear.

 

[JohnInStockie]

Cheers Lloyd.

I know of hydraulic brakes, but does anyone know of any form of ABS for the back brake?

John

 

[Lloyd_50cycles]

Well actually shimano make a power modulator for v brakes. It's very simple, just a spring mounted in the cable noodle(the silver 90 degree pipe sticking out of the brake cantilever arm on one side. ) What it does is allows more modulation on the brake. So it basically makes your brake lever feels a bit more spongy. It does help a little, but people either love it or hate it. Bit of a marmite thing.

 

[flecc]

There's no true ABS for bikes John, though you'll find claimed ABS systems out there. What those are in fact is coupled brakes, both operating together so that the system sorts the braking proportion that Lloyd mentioned. I know these from some motorbikes like the Honda CBS1000 for example and haven't go a high opinion of them. That opinion is shared by most who try them.
.

 

[JohnInStockie]

Thanks Guys

Maybe I could try changing the actual blocks themselves, are there any recommended brake blocks that spring to mind?

John

 

[john]

I recently changed my brake blocks for Koolstop. They are excellent in wet or dry and have a sprung part to provide modulation.

 

[Danny-K]

Hi Guys

just wondering if it was me, but yesterday I was riding home with panniers in the wet, one pannier heavier than the other. I applied my rear brake which seemed at first not to slow me down and then suddenly locked, and the whole bike skidded to one side !!!

Is that normal? Would it be the panniers causing that or something with the brakes themselves?

Thanks

John

John, I think the clues to your 'fright' are all contained in your description of the incident.

First clue: 'in the wet'.

Possibly, (assuming you hadn't experienced this phenomenon in lighter rainy conditions), there was so much rain about, (it has been exceptionally heavy this week), that at first the brake blocks were having a hard time of shifting the excess water as the brake-blocks closed tighter on the rim.

Second clue: 'which seemed at first not to slow me down and then suddenly locked'.

Finally the blocks are biting through the excess rain and at last bite cleanly, however, by this time, alarmed by the lack of reaction, you are possibly applying so much pressure via the brake levers to get some action from the brakes that the pressure you were applying had now reached 'emergency stop' levels. Combine that with a very wet road, possibly a little bit of kinetic energy from the odd leaves on the road, (it has been windy this week too), and hey-presto! There's enough lock at the rear to produce a skid.

Unless you've already completed a high mileage I'd hazard a guess that your original brake blocks are still in serviceable condition. It's just that you've been cycling in the worst weather conditions, (ie., rain!) suffered in any August for 60 years according to news reports. I really don't think you have been provided with inferior brakes. I'd blame exceptional weather conditions in this instance; just be more aware of the longer time needed in the wet before applying greater pressure to the brakes - however you can have a lot of fun experimenting with alternative brake blocks; for instance my favourite used to be the Aztec blocks. Kool-stop are great too.

P.S. You make no mention of applying the front brake - quickest way to induce a rear wheel skid is to use the rear brake only. Lloyd is 100% correct - nearly all the braking force is delivered by the front brake as the bike's load is thrown forwards to bear down on the front wheel. In the wet though apply braking gently and slow down earlier than you would in the dry. Use BOTH brakes. When out riding on either bicycles or motorbikes the two most dangerous times where your life is at higher risk are:

a) in the wet,
and
b) In the dark.

- When riding where you encounter both conditions at once, forget speed, forget fierce braking, and ride with more circumspection than normal - it's survival time, pure and simple! I always try to avoid being out in either conditions where at all possible.

P.P.S. I read one hugely experienced, (lifetime total of several million miles riding), round-the-world motorcyclist's book where he writes that he absolutely will not ride in either conditions whatsoever. Period!

 

[flecc]

When out riding on either bicycles or motorbikes the two most dangerous times where your life is at higher risk are:

a) in the wet,
and
b) In the dark.

P.P.S. I read one hugely experienced, (lifetime total of several million miles riding), round-the-world motorcyclist's book where he writes that he absolutely will not ride in either conditions whatsoever. Period!

I've been cycling for 62 years and I will not ride in the dark, not now, not ever.

I'd also prefer never to ride in the rain, but in England that means giving up cycling.
.

 

[frank9755]

I came home from work in the heaviest rain I can remember. My brakes were significantly less effective, even though I reduced my speed, especially downhill. Like John, I've recently switched to Koolstop blocks, which are supposed to be good in the wet, but performance today was a bit disappointing. Maybe a bit harsh as conditions were extreme (2-inch deep river of water on the road!)

Normally I hardly use my rear brake at all, but in tonight's conditions two brakes were needed to stop the bike, but with the front brake doing most of the work.

As a commuter, I do ride in the dark, but one thing I have noticed is that my mirror is much less useful at night than during the day.