Alarming ride in downpour today – braking advice

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Alarming ride in downpour today – braking advice

Postby Slow Loris » Fri Jul 25, 2014 6:31 pm

I'm probably more timid than most, but bear with me. I'm interested in any advice on controlling speed on a long downhill stretch in a thunderstorm :shock: – having just experienced it this afternoon, thankfully without incident. It's a busy 20mph zone peppered with zebra crossings and traffic islands. I normally bomb down here in the dry, taking care when approaching the crossings. However, I was worried today with such poor visibility – my rear wheel 'fishtailed' when I braked at a junction earlier on and I didn't want to risk a collision with anyone, so I kept under the speed limit in primary. Fortunately the van and Addison Lee drivers behind hung back and gave me loads of room when overtaking :) . I suspect I may have been too heavy on the rear brake when I had the skid, but despite slowing on the downhill stretch, I didn't have much confidence I'd be able to stop safely at any of the crossings if needed. I have Deore V brakes, but they seem less powerful than the Tektro V brakes on my mountain bike. What do you do to stay upright in these conditions - other than pray?
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Re: Alarming ride in downpour today – braking advice

Postby Si » Fri Jul 25, 2014 7:05 pm

A _possible_ problem that you may have had was that when you first applied the brakes you didn't get much retardation as the rims were wet. This would naturally lead you to squeeze the lever harder, suddenly the rim dries up and the brake comes on full whack causing a bit of lock-up. I find the key in these situations is to squidge the brakes now and then to dry the rims before you are going to have to use them for actual stopping. If you see somewhere that you think that you might have to stop then get on the brakes early and lightly to wipe the wet off.

Or get good discs that allow plenty of control rather than a straight choice between on and off , and tyres with a bigger footprint to get a better grip (remember that bike tyres don't aquaplane due to the low speeds they are used at) :wink:
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Re: Alarming ride in downpour today – braking advice

Postby Vantage » Fri Jul 25, 2014 7:43 pm

Have a look at your tyre pressures also, if they're too hard they'll slip more easily.
The recent heat and sudden wet conditions could have made the road 'greasy' too. I read about this, no actual experience of it though.
I tend to drag my brakes for a bit before I need to slow or stop, although this only works if you know when/where you're slowing/braking or can predict the future :)
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Re: Alarming ride in downpour today – braking advice

Postby brynpoeth » Fri Jul 25, 2014 7:58 pm

Try a back-pedal hub brake, you can't have too many brakes!
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Re: Alarming ride in downpour today – braking advice

Postby irc » Fri Jul 25, 2014 8:00 pm

It's well known that the first rain after a long dry spell produces a very greasy road surface as oil, rubber, and anything else deposited on the road mixes with the rain to produce a dangerously slippy surface. This may well be what caused your rear brake skid. Your braking technique was probably correct as favouring the rear in slippy conditions means a skid is likely to be a rear wheel skid which can be controlled.

The first rain is particularly dangerous at junctions as there tends to be more diesel spills while vehicles are stopped and more rubber left on the surface as vehicles brake/accelerate at the junction.

In wet conditions it's worth applying the brakes lightly every so ofte to dry the rims so that should you need to brake harder they are already dry and there isn't a delay while water is cleared off the rims.
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Re: Alarming ride in downpour today – braking advice

Postby drossall » Fri Jul 25, 2014 9:30 pm

But do use both brakes. Bikes are just like cars - braking throws the weight onto the front wheel and off the rear, so the rear skids much more easily.

It's basically a choice - front wheel skids are less likely, but catastrophic, whilst rear wheel skids are more likely but sometimes controllable. Using both brakes avoids putting either wheel into a skid situation (assuming it's not emergency braking).

Brake early and often, aiming to get the rims dry-ish before you need to brake hard. Brake well before corners, where leaning is going to increase the chances of a skid - if you can, don't brake at all in corners, and certainly don't brake hard. Keep off painted surfaces and drains, especially when leaning - they have no grip in the wet.

Braking much earlier allows time for the reduced performance that you get in the wet.
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Re: Alarming ride in downpour today – braking advice

Postby drossall » Fri Jul 25, 2014 9:32 pm

Slow Loris wrote:I have Deore V brakes, but they seem less powerful than the Tektro V brakes on my mountain bike.

More likely to be about how they are adjusted (or possibly the quality of the brake pads, if they've been changed) that the make of brake, I'd have thought.
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Re: Alarming ride in downpour today – braking advice

Postby Vorpal » Fri Jul 25, 2014 9:54 pm

+1 for what drossall said. Rear brakes are okay for taking some speed off on a hill, but front brakes work better for stopping and are less likely to result in a skid.

Try practicing someplace relatively safe, like the empty corner of an industrial estate car park, or something. Try stopping with both brakes and either. Dont send yourself over your front handlebars, but try stopping very quickly. Shift your weight back when you do it.

It may be more comfortable if you put the rear brake on ever so slightly before the front one, but if you can, practice in the wet, as well as dry conditions.
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Re: Alarming ride in downpour today – braking advice

Postby Vantage » Fri Jul 25, 2014 10:48 pm

All good advice, especially that of front and rear brake use. I will add one more thing which is easier said than done, learn how your bike handles.
I can pretty much guess how far I can push my bike in most conditions, how far I can lean before toppling off or sliding off, how much pressure I can put on the brakes before they lock or throw me off come rain or shine.
Here's hoping I never guess wrong :shock:
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Re: Alarming ride in downpour today – braking advice

Postby Neilo » Sat Jul 26, 2014 7:37 am

Had a front wheel skid when I was on a wet grassy slope on my mountain bike. Scared the life out of me, there was a wall at the bottom of the slope. First time I've used cadence braking on a bike http://en.wikipedia.org/wiki/Cadence_braking
I was fortunate that I was going down the hill square to the slope, so there was no lateral force to wash out the front wheel.
Something in the tool box for the future.

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Re: Alarming ride in downpour today – braking advice

Postby Slow Loris » Sat Jul 26, 2014 10:15 am

Many thanks for all the helpful replies. I use both brakes, with the rear one fractionally earlier than the front. I do need to be more skilled, though, so will practice somewhere quieter. I hadn't realised about squidging them often on the road – I usually do this to clear off mud from cyclepaths in the rain.

The brake pads were new a couple of months ago and I thought they'd bedded in by now, but they could very well need adjusting as they sometimes make a noise in the dry and feel slightly less effective than those on my MTB. Haven't had a skid for a very long while so I was quite unnerved.

Vantage - Interesting point about tyre pressure as I'd inflated the rear to 1 bar below max that morning. Ditto for bike handling - this is a relatively new bike and lighter than what I've been used to, so I'm still familiarising myself. It's noticeable that there is much less room for error than on the heavy duty MTB.

As for front wheel skids - I certainly hope I can avoid those :shock: :shock: :shock:
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Re: Alarming ride in downpour today – braking advice

Postby drossall » Sat Jul 26, 2014 2:10 pm

Certainly not all brake pads are created equal. If you aren't happy with the performance of your brakes, try to establish what pads you have. Either get what you've got on the other bike, or get some recommendations here (which may depend on the type of riding you do, and what rims you have).
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Re: Alarming ride in downpour today – braking advice

Postby Vorpal » Sat Jul 26, 2014 11:02 pm

Tyres can make big difference, too. The Marathons on my hybrid are more likely to skid or lose traction than the Continental 4 Seasons on my road bike.
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Re: Alarming ride in downpour today – braking advice

Postby Tonyf33 » Sat Jul 26, 2014 11:49 pm

This might seem harsh but the simple solution is..SLOW DOWN, you openly admit to not being able to brake enough to stop at a crossing yet you still continued on at a speed far in advance of a safe amount that it worried you. Yet there are multiple pedestrian crossings and you still chose to go at an uncrontrollable speed, that's massively irresponsible!

what aspect of going too fast for the conditions did you not understand, you not only put other road users (especially pedestrians) at risk but yourself, IF there had being someone there legitimately crossing and you crashed into them with the potential for serious injury, then as a cyclist you may end up doing time in prison (As happened last year).

'Bombing' down a road even in the dry has its dangers especially since it is 'busy' and from the phrase you use to describe your cycling down the hill it seems to me you are an accident waiting to happen in the wet or in the dry.
I would hardly call someone able to bomb down a busy road as timid :roll:
That might all sound really harsh but it's meant as a wake up call because you either start to understand your and your bikes limitations and slow down or you'll end up in a shed load of bother and probably drag an innocent person into it.
The advice above regarding use of brakes is to be heeded BUT NOT tested at the limit of your ability in the wet OR dry especially on a busy road!!
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Re: Alarming ride in downpour today – braking advice

Postby Slow Loris » Mon Jul 28, 2014 2:39 pm

Appreciate the comments regarding brake pads and tyres – I remember seeing Kool Stop salmons recommended here before. My rims are Mavic X517. Not sure what pads are already fitted but I can find out.

I normally bomb down here in the dry, taking care when approaching the crossings.

I can see this could have been phrased better and misrepresents my riding style, so to clarify: I fully agree that one should cycle according to conditions and visibility, and take care to do so. I know this road well and keep my speed under control, slowing well in advance of all the crossings. I've mentioned elsewhere in a different thread that motorists often accelerate to overtake me at such points. Aggressive driving is commonplace and outside of approaching crossings, it is necessary to keep up with the traffic and stay in primary. The rear skid happened on another road earlier on, and at slow speed, while I was preparing to stop at a junction. I understand now that there could be a number of causes for this. On the described downhill stretch in heavy rain, I was on the brakes all the way but was still concerned about the rear wheel locking up and throwing me off – hence my request for advice in the original post.

All replies taken on board - thanks again.
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