Bicycles on Planes - Stupid Question of Week

[A Squared]

If a 7psi pressure differential is enough to split open a Comet (even with the metal fatigue) then might it not also do the same to a bicycle tire?

No, very unlikely. Not saying it can't happen, but a bicycle tire is a little different than an airplane fuselage. A bicycle tire is tough and resiliant and a 7 psi change in pressure is *very* small compared to the ultimate load. When I was a kid, my friends and I took our bikes down the the local filling station and filled the tires to 120 psi, mostly because we didn't know any better. If I recall correctly, those tires were supposed to have 30 psi, so that was a 300 % overload. They didn't burst, although I wouldn't recommend trying this. Even a relatively low pressure mountain bike tire is intended to normally hold 40-50 psi, plus being continuously hammered on rocks. They can probably hold twice that pressure pretty easily. Many road bike tires are designed to run at 120 psi or even more. A change in pressure differential of 7 psi, is just small potatos for a bike tire. That small a pressure increase may happen merely by hitting a stone while riding, and certainly over inflating a tire by 7 psi is pretty common. It's equivelant to the difference between 40 psi and 47 psi on a mountain bike. trust me, a mountain bike tire is nowhere near bursting at 47 psi.

An airplane fuselage is a different story, entirely. 7 psi is the entire normal load. The margins are much thinner. I don't know what specs the Comet was certificated under, but Part 25 only requires aircraft to be designed for 1.67 times the max relief valve setting. There may be some other factors which are applied to this, I don't know, but all in all, it's a fairly low pressure assembly. It's quite possible that a correctly designed and manufactured fuselage would rupture at 15 psi. for sure, it would rupture long bfore the pressure got to 30 psi, so 7 psi is a much rgreater portion of hte ultimate strength of the fuselage than it is a bicycle tire. And remember, that the COmet fuselage wasn't a new structure in good condition, it was already compomised by a developing fatigure crack.

 

[Swass]

Also, don't put a gas station airhose up your butt to get high, you might explode like a Comet.

 

[CrimsonEclipse]

If a 7psi pressure differential is enough to split open a Comet (even with the metal fatigue) then might it not also do the same to a bicycle tire?

You're kinda comparing apples to oranges.
The comet was due to metal fatigue and square windows.
The square windows created a stress point (or focus) on the corners
which allowed cracks to form over time. The multiple cycles weakened
the metal by work hardening the material. Also the airframe wasn't
designed with damage control (crack propagation prevention) in mind.

Apples to apples.
Pump your tire to the normal pressure. For instance 30 PSI.
Now increase the pressure by 15PSI (if you can read 14.7 on your
floor pump, more power to ya!). Did the tire ASSPLODE?

If no: Put it in the airplane and don't worry about it.
If yes: quit buying tires at Walmart.

Remember, to OUTTER SPACE, it's only 14.7 PSI.

...and then there's this new trend of putting Nitrogen in auto and
bicycle tires....don't even get me started....

CE

 

[Goose Egg]

Frankly, anyone who feels they have to call a folding bike "gay", almost certainly has some maturity issues, at the very least.

Yeah, I get that a lot.

-Goose

 

[Goose Egg]

A more universal question, what is everyone out there riding?

Specialized Hard Rock FSA1 Comp c. 1999 - Cheap bike but love it to pieces. May be bumping up the componentry to LX. Well overdue for new pedals. I doubt I'll every own any mountain bike other than Specialized.

Cannondale R800 c. 1997 (so we're talking CAAD3), 105 everything except a Dura-ace shifter aftermarket. Good ride.


-Goose

 

[Caveman]

Ellsworth Joker X/C (all XT)
Litespeed Solano (all DuraAce)
Surly Crosscheck (singlespeed)

Bought all 3 framesets and spec built them myself. Just finished a road ride and I'm reading this thread all doped up on endorphines (sp?). Best high there is IMO.

 

[Goose Egg]

Is wierd that I still prefer hardtails and v-brakes on an MTB?

-Goose

 

[Caveman]

Hardtails? No that's not weird. I tend to agree with you. Disc brakes are another thing. I'm never going back to V-brakes in the dirt.

 

[Goose Egg]

Disc brakes are another thing. I'm never going back to V-brakes in the dirt.

Yeah, probably shouldn't knock 'em 'till I've tried 'em.

-Goose

 

[seethru]

I bought a Sherpa MTB (not even sure if they make 'em anymore) about 10 years ago. It mostly sat in my garage until a couple of months ago when I started riding with some partners.

I'm very delighted with the low impact cardio, and now I wish I had picked it up sooner. I've been slowly upgrading components and use the bike strictly for roads, although eventually I would like to try out some trails some time.

 

[Caveman]

I'm very delighted with the low impact cardio, and now I wish I had picked it up sooner.

That's how I got into cycling. I was sick of running and started mountain biking back in the late 80's. I'm more of a roadie these days, but I still like riding in the dirt about once a week.

Anybody watch Landis today? Lance who? That was the best ride I've ever seen in the TdF and I've been watching it for many years. It was an amazing effort. Well done Floyd!

 

[Goose Egg]

That's how I got into cycling. I was sick of running and started mountain biking back in the late 80's. I'm more of a roadie these days, but I still like riding in the dirt about once a week.

I picked up mountain biking for the sole purpose of avoiding running for cardio workout. Danged if it didn't grow on me, and pretty soon I was out there just because it was fun, and a good cardio was just a secondary benefit. That's the way it should be.

Anybody watch Landis today? Lance who? That was the best ride I've ever seen in the TdF and I've been watching it for many years. It was an amazing effort. Well done Floyd!

I'm taping it as we speak. I still haven't seen all of yesterday's stage (taped that too.) I've seen every stage this year so far. I'm glad to hear that Floyd did well. I just don't want to hear how well until I've had a chance to watch it!

-Goose

 

[Immelman]

I have a cannondale xr800 - r800 but a 'cross bike (105 and hand built wheels).. have almost 6000 miles on it!! its treated me well, except for the stiff aluminum ride over bumps

and, just last this past saturday, I took delivery of a proper road/racing bike so that I can keep my cross bike for tail use: a kestrel talon. full ultegra and easton/veloace cicuit wheels... put about 80 miles on it so far this week, and am looking forward to putting on aero bars for triathlon use.

 

[shamrock]

Anybody watch Landis today? Lance who? That was the best ride I've ever seen in the TdF and I've been watching it for many years. It was an amazing effort. Well done Floyd!

Pretty impressive. I was hoping Sastre would get the Yellow for a day, but Pereiro has to go and screw it up. :angryfire

For supposedly being such a joker, Floyd sure is pretty damn dull interview.

And as for what I ride, a new Cervelo R3 (Campy Chorus) or a 2 year old Cannondale R1000 (Ultegra), depending on the weather, in ATL and a Trek 2300 when I'm at the folks house in CT.

Haven't gotten around to a MTB yet, but it's in the cards. I'm thinking a good old hardtail Stumpjumper.

 

[LearLove]

"For supposedly being such a joker, Floyd sure is pretty dang dull interview"

All us Pennsylvania Dutch are like that.

 

[Goose Egg]

Anybody watch Landis today? Lance who? That was the best ride I've ever seen in the TdF and I've been watching it for many years. It was an amazing effort. Well done Floyd!

And I'm lucky enough to have captured it on video tape. Awesome!!!

-Goose

Edit: I just noticed that the CSC of team CSC is the same as the CSC Duats that I use with semi-regular frequency. Sweet. Dave Zabriskie is from my home state.

 

[steveg]

Impressive nothing. That was downright incredible. Made me a big fan. I've hit the wall like he did, and it took a looooooooong time to recover. Considering his hip and all, Floyd is very impressive.

I'm on a Lyon sport touring bike with Ultegra/DA for my main ride, a low end Masi for the trainer/backup, and a Raleigh MTB that I don't use much.

That Cervelo is nice, how in the world can you afford that on RJ fo pay? I'm thinking about getting a Ritchey break-away to occasionally travel with and use as a race bike.

 

[mhcasey]

Landis is the freakin man.

Specialized mountain bikes are awesome.

Cannondale aluminum bikes could be better, but I'll deal with it. At least it came with Ksyrium Elites.

 

[shamrock]

That Cervelo is nice, how in the world can you afford that on RJ fo pay?

Misguided priorities and large credit lines are a dangerous combination.

I actually bought a Cervelo R2.5 Chorus (which cost less than the R3 does now) and the frame broke. Because Cervelo isn't making the 2.5 anymore they had to replace it with an R3, so I made out pretty well. Now I'm "that guy", the one you see out on rides who's abilities will never come close to matching those of his bike. Then again, that would probably be true on a $500 bike too. :0

Cannondale aluminum bikes could be better, but I'll deal with it.

I second that. I didn't realize how harsh a ride my Cannondale was until I got my Cervelo. In hindsight I should have bought another Trek instead of a Cannondale but, as you said, I'll deal with it.

 

[steveg]

Yeah, I hear you about C'dales. I rode a Century with a guy last year that had one. I swear it made me sore just being close to it!

Let's not even start the discussion about being close to our bikes abilities. I'm pretty sure I'd have everyone beat ( or is it lose to everyone? ) on that. I'm thinking about starting up a side business hiring myself out to bike companies as a tester. If their bike can hold up under me, then it is one tough freakin' bike.

Gonna' miss the TT tomm. I'm thinking it'll top LA passing Ulle, and possibly LeMond and Hinault. Can't believe I'm going to miss it.