Blowout down hill - is it dangerous?

markiegrim

Third ride on my new bike and I already have a flat

Front tyre popped going around 30 mph down a steep hill. I didn't lose control, but was I just lucky?

Can I expect to normally lose control when this happens down hill? What about if it had been the back wheel?

Also, once blown, will my weight damage the wheel - especially back?

Also, how often should I expect flats on a road bike...getting one after just 2 weeks seems a pain in the ass

Thanks all

M

topdude

was I just lucky?

very lucky, could have ended in A&E. You could easily lose control if either tyre burst.

will my weight damage the wheel

yes you could easily damage the rim.

how often should I expect flats on a road bike

it depends on so many things, start with better puncture resistant tyres. Look at this post http://www.bikeradar.com/forums/viewtopic.php?f=40042&t=12942240

desweller

Rims are pretty strong. Your weight won't permanently damage the rim on its own (i.e. you might get some burrs that you'd have to dress off with some wet'n'dry or a needle file), but if you hit a pothole with a flat tyre you could put a ding in the rim that you'd struggle to correct.

Losing the rear tyre is usually much more controllable than losing the front. It wants to follow the front wheel, so just do your best to travel in a straight line and you can bring the bike to a controlled halt. Front tyre failures, particularly fast deflations, are much harder to deal with. The principle is the same, though; stay upright (i.e. straight), don't snatch the brakes, try to come to a gentle halt.

What kind of puncture did you get? Road tyres are usually pretty good, but it does depend on where you live; round here the worst I have to contend with is stuff like occassional broken glass and thorns when the farmers trim their hedges. But if you live in a flinty area then the rain can wash all kinds of nasty rubbish into the road. It's important to keep your pressures up too, or you'll be at risk of pinch flats (where you hit a pothole and, because the tyre pressure is not high enough, the rim squashes the inner tube and tyre against the edge of the hole).

I have had one puncture this year, from riding into a big pothole at 25mph on my way back from work during the winter. Not too bad for 3000 miles.

MichaelW

I've had a sidwall failure going downhill. The tyre exploded and I lost a lot of control and traction but the bike kept rolling along.
Don't suddenly apply the brakes, try and keep rolling in a straight line, free of any potholes or bumps. Watch for a good runoff zone where you can bounce or skitter along the road or verge rather than slam against a wall, barbed wire fence, gate or bank.
Apply the brake of the good tyre and maintain balance.

You can fix a tyre blowout with a tyre boot, a large, tough patch material. £10 notes, ductape, plastic sweet wrappers can all be used but I carry a Park Tools boot.

markiegrim

I have the standard tyres that came with my Trek 1.5. They look very slick

I live in the Chilterns. Country roads have lots of grit and gravel. But not on the particular hill I was going down. Guess something may have got lodged. I already scratched a rim with somethinnasty lodged in the brake pad

Above posts make me pretty nervous I have to say! I do a lot of fast downhills around where I live

ianspeare

I had both blow out at about 35mph coming down the Great Orme. Hit a small rock & had very little control and felt myself drifting towards the kerb (only a narrow path, stone wall and then a steep drop) Managed to come to a stop by braking gently and very very gently steering. I had smoke coming from the tyres and I don't know how the hell I managed to stay upright. Needles to say I definitely had to was the shorts that night!

This was on an audax and I took a short cut to get back to the group with the help of one of the organisers. On the next major hill, I looked back to see the rest of the riders behind me!

The rims held up allright, just needed a little truing after.

Since then, I've been so careful on descents, especially when it's dark, such as a wooded area. You just can't see what's on the road in terms of debris or potholes. I used to have a fair few punctures, but have been told that my tyre pressure was too low. Got some gator skins and proper continental inner tubes and inflate to around 100psi+ to avoid the pinches

cougie

They're pretty rare. I blew a tyre in the alps - combination of too high a pressure, the heat and braking.
Luckily I was on a corner with a run off.

I've swapped to conti gp4000s and p******s are a thing of the past. Excellent tyres.

bompington

I too hit a stone coming downhill once - at 50mph :shock:. Front tyre blew completely with a loud bang, amazingly everything stayed in order as I shifted as far back as possible to brake gently to a halt. I think I was lucky.

pilot_pete

First thing to change on a new road bike purchase are the tyres, especially on a bike costing less than about £3k as they seem to increase their profit margins by fitting a bottom of the range tyre badged with their brand and call them 'special'.

I learnt this after a similar incident. Was descending and turning at 35+mph in the Peaks, in a group when my front went with a bang. I managed to lift the bike slightly more upright whilst braking with my rear wheel only as I started t head towards the verge. Luckily the verge was kerb less and about 8"" tall; just mud, stones, grass etc. I used that to keep the turn going as I slowed to a halt, some several metres past the exit of the corner. The sound of rim on road was horrible! However, new tube and tyre patch got me home and I went straight online and bought some Conti GP4000s tyres and have not looked back since.

PP

markiegrim

Am I using the term "blow out" incorrectly? The tire was fine, just an instantaneous deflation of front tube, with pop rather than a dramatic bang. Is that why I did not lose control...because tyre was fine? Or is a rapid deflation as good as a "blow out" and so should still count myself lucky? Inspection of the tube indicates a small hole

The reason I ponder is that, I am inclined to get better tyres, just not immediately. I wonder if I am taking too much of a risk by carrying on...the tyres are Bontrager R1...surely cannot be absolutely pants?!?

Otherwise, cheers for all these very scary stories!

Monty Dog

Front wheel blow-out can be one of the worst, particularly at high speed on a bend - bare aluminium has very little grip. One of the reasons to keep close attention on the condition of your tyres. With new bikes, they are often assembled in high humidity conditions and inner tubes stick to the outer - worth taking them out and applying talc to stop them sticking.

me-109

Road bike tyres are so thin and the sidewalls so soft that they deflate flat like a tubular tyre, forming a thin layer between the road and the rim (within reason). As long as you don't try any fast cornering you'll be able to bring it to a controlled stop easily enough. Big wobbly MTB tyres on tarmac or hardpack give you much more wobble. Just remember the longer you roll on the deflated tyre, the worse condition the tube and tyre are going to be.

racingcondor

There are plenty of rubbish tyres out there and you often find £10 RRP tyres on new bikes. Personally I would put some GP4000S on there and enjoy.

Re your flat. Glad you stayed up, it's not necessarily a bad tyre though. Could easily have just been bad luck, punctures happen occasionally and it's often not easy to see any reason for them (not always after riding through glass or anything obvious like that). If it helps I've never crashed as a result of a flat (around 8 years of riding).

700c

front tyre blowout on a fast descent is the stuff of my nightmares! or at least, it pops into my mind when I'm plummeting down a hill over 40 mph!

having a rapid front puncture (blowout)on a fast downhill descent is something that could well have caused a crash and if you had been going round a corner, even more so. so I do think you are both lucky to be fine and unlucky to have had a flat in the first place.

As others have said, better quality tyres can only help.

I am told that one of the reasons pros use tubulars rather than clinchers is that they are safer when you puncture on a fast downhill as they stay on the rim. This would seem to make sense, but I imagine you could still lose control quite easily regardless of type of tyre.