Road Cycling - High pressure, worry!

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View Full Version : High pressure, worry!


willic
02-14-02, 02:00 AM
Hi all!

Having just aquired myself a spanking new road/racing bike, and looking foward to the spring , attacking all the hills around my neck of the woods, doing 50 miler`s, with the odd (i hope) century thrown in.

It has been many years since i have road/owned a similar cycle.
In the interveening years of course cycle tyres have progressivley decreased in width , tyre pressures have become much higher, so! a thought rather perturbing me when i stare at the 21mm , 120 psi tyres on my new machine .
What happens? if i get, a say 25+mph blow out in the front wheel . Have any of you guys/gals experienced such a scenario , im sure you have , I fully expect there will be a loud crack as th`o someone has just fired a gun near you .
What i am unaware of is the reaction from the bike, is there a sudden loss of control of the bike , can it be dangerous!
the idea of being pitched off the bike in this situation, especially with lots of motorised traffic around seems quite scary or maybe I am just being a little paranoid about it.

regards Willi`c


D*Alex
02-14-02, 05:15 AM
Buy decent tyres, then you don't need to worry so much. I normally ride tubulars, and they stay glued even when flat.

DnvrFox
02-14-02, 05:20 AM
As Alex says, get good tires, and learn how to mount them properly so you don't get pinch flats, check them often. I have had one blowout in 6,600 miles and kept control just fine. The high pressure will actually help prevent blow outs. I keep mine at 120 psi and check the pressure weekly or more often. I ride clinchers.


chewa
02-14-02, 06:14 AM
I've had one blowout on a 120 psi tyre in the past, and it didn't feel any worse than on a 90 psi. It was a bit louder.

MichaelW
02-14-02, 06:18 AM
You can proof test tyres at higher than recomended pressure. This is a good test for worn rims as well, but wear safety specs in case the rim or tyre explode. just remember to deflate to normal pressure afterwards.
Ive had front blow outs at 90psi. Just dont panic or brake on the front wheel.

willic
02-14-02, 06:26 AM
Thanks guys!

The tyre`s that came with the bike are Michelin Axial Pro`s ,(tubed) are they a quality type.
Tyres were not a major concern when I was picking and choosing components for the new cycle , just left it to the bike shop to come up with something appro`e.
If they are not to good should i change them to help aleviate my fears!

regards Willi`c

MichaelW
02-14-02, 06:46 AM
The tyres are fine in terms of quality. The pressure specs on the tyre walls are always conservative to please the lawyers.

If you are not racing, it may be better to switch to a wider tyres. 25mm will probably fit your bike, and provide a more comfortable ride, esp on longer rides.

pucci
02-14-02, 07:10 AM
If you keep your tires inflated right, modern tires will blow out less frequently than old fasioned ones. If you overinflate, they can blow, though.

I blew out a rear (tubular) tire on a descent off a mountain pass at 70kph. The tire blew right off the rim and caught between the wheel and the stays. @That locked the wheel up and I ground about 2mm. off the bare rim as it dragged on the asphalt. The guy behind me said he saw the sparks coming off the wheel.

It took about 10 meters to stop, but somehow the bike stayed upright. It turns out that the gauge on my pump was reading low and I had actually overfilled the tire to 135psi.

Anyway, make sure your gauge is right and use it.

Greg
02-14-02, 07:47 AM
Originally posted by willic
What happens? if i get, a say 25+mph blow out in the front wheel.

Thanks for reminding me of my worst fear.

I've never actually heard of anyone dying from this senario, but it always seems to haunt me.

Before each steep decent I always do a quick visual scan of the tires for low pressure. On a few occaisions, I've pedalled away from the bottom of a huge hill and found a tire flat. On these occaisions I give thanks to anyone that'll hear.

An actual all out blow out would be hairy.

I think the Axial Pro is rated at 110psi.

ljbike
02-14-02, 08:01 AM
You shouldn't have any trouble with those Axial Pros unless you make a habit of running through broken glass, or falling into pot holes and other kinds of debris.
I've got over a thousand miles on mine with no problems. As stated above you need to stay relaxed, without panic, if you should get a flat.
For peace of mind you might consider a tire liner that goes between the tube and the casing. I, personally, don't think you need them, but you have to be the judge.

MichaelW
02-14-02, 08:14 AM
If you are going to come off your bike, then downhill is the best palce. You will slide down the hill, decelerating slowly, with a few cuts and bruises, and road rash to bare skin.
It is sudden stops which do the real damage.

Last year in the TdF, one guy came off his bike during a fast descent, and flew right off the side of the mountain. He bounced down the hill, on scrub and bushes, and walked back up to the road.

a2psyklnut
02-14-02, 09:41 AM
Yeah, I think that was Jan Ulrich (sp?) trying to catch Lance! Yeah Right!

lotek
02-14-02, 09:42 AM
Michael

I believe that the guy you're referring to
is Jan Ullrich. Pretty spectacular crash.
However, these guys are pros, I doubt that us
normal folks would have the presence of mind
to not panic and ride it out....

Marty

MichaelW
02-14-02, 09:59 AM
I wonder what was going through Jan's mind as his bike left the road and headed out over the mountainside.
"Im a pro, a lean, mean winning machine; I can handle this"
or
"Holy f****ng s**t, Aaaaaaaaaaah"

Louis
02-14-02, 12:44 PM
"Holy f****ng s**t, Aaaaaaaaaaah" gets my vote. :D

Back in the 80's, I rode Specialized Turbo R's, which were a very lightweight 20mm tire. I had a few blowouts at speed with no disasterous results.

Those Michelins on your new bike are fine. Just keep the air pressure up, as mentioned above.

Congratulations on the new bike.