Do you think inflating tyres of bicycles with Helium instead of air would make them significantly lighter?
2006-10-12 11:44:36 · 10 answers · asked by Alexis (From France) 1 in Science & Mathematics ➔ Physics
Yes, actually! The air in a tire weighs around 250 grams for a road tire, and 1000 grams for a mountain bike tire (depending on the pressure and exact dimensions). Helium weighs 2/7 what air does at any given pressure. If you're trying to get your bike down to 15 kg (Tour de France level), that may be a good way to do so for less money.
This might not be a good idea, though, because helium is able to leak much more easily (a helium atom is much smaller than your average molecule of air), so you may have a problem with needing to inflate more often. This is a fascinating idea though!
Don't worry about the comments about the effect on stability. The tires and rims should weigh more than enough to give you the gyroscopic effect (angular momentum) that makes the bike stable. (note that the momentum has nothing to do with "efficiency")
2006-10-12 12:33:56 · answer #1 · answered by Gabe 1 · 1⤊ 0⤋
"In fact, if a bike tire was filled with helium, the rotational inertia would be less and your performance would actually suffer."
In fact, lighter rotational inertia is a much sought after performance enhancement. Otherwise cyclists would be installing lead weights on the rim.
Using the perfect gas law, at 100 psi, helium weighs about 2 lb/ft^3
same conditions, air weighs about 16 lbs / ft^3
the volume of a 700 mm dia tire... about 16 in^3
so 16 lbs/ft^3 / 1728 cu in / cu ft = .0093 lbs / in^3... x 16 in^3 = 0.148 lbs of air or 2.37 oz and then 0.29 oz for He.
looks like you'd save 2 oz per wheel.
2006-10-12 12:38:48 · answer #2 · answered by Holden 5 · 1⤊ 0⤋
If you filled a bike tire with helium...yes it would be lighter. Would you be able to tell the difference? No. Think about how big the Goodyear blimp has to be to be able to float in air.
In fact, if a bike tire was filled with helium, the rotational inertia would be less and your performance would actually suffer.
2006-10-12 11:55:40 · answer #3 · answered by Professor 3 · 1⤊ 0⤋
Not much volume to make a difference.
The other problem with Helium is it's much harder contain. Helium really leaks since the H2 molecule is much smaller than N2+O2 (air).
2006-10-12 11:52:30 · answer #4 · answered by Morey000 7 · 0⤊ 0⤋
you additionally could have observed that He crammed balloons rapidly deflate (over an afternoon or so) on the grounds that He somewhat in basic terms diffuses for the period of the rubber. so which you will get insignificant weight saving in return for top value, sensible issues bodily filling the tires to the mandatory rigidity, and despite in case you would be able to desire to do it, the tires would bypass flat fairly at as quickly as. in case you rather need to leave from air an enhanced decision would be Nitrogen because of the fact that's inert. That suggested, the clever benefit is small ... and that's plenty extra no longer common to get Nitrogen right into a tire (besides the undeniable fact that a Volkswagen or Audi broking probable has the kit on the grounds that they do it for motor vehicle tires.
2016-12-26 17:47:52 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Not significantly, and helium leaks out faster.
2006-10-13 10:59:02 · answer #6 · answered by Nomadd 7 · 0⤊ 0⤋
Yes, it would; but the tires are where you really want MORE mass! By building up momentum in its wheels the bike can travel more efficiently.
2006-10-12 12:24:54 · answer #7 · answered by poorcocoboiboi 6 · 0⤊ 0⤋
Not much lighter, but by a little bit.
Helium is much less dense than air.
2006-10-12 11:51:51 · answer #8 · answered by S.M. 2 · 0⤊ 0⤋
By about 1 lb or less
2006-10-12 11:49:00 · answer #9 · answered by Anonymous · 0⤊ 1⤋
no way. not even close to enough volume to make a difference.
2006-10-12 11:49:01 · answer #10 · answered by BigTime 2 · 0⤊ 0⤋