tire pressure Q

[maillotpois]

This from Sheldon Brown, debunking a myth with some humor:

> 4) Deflating my tubulars after riding them will allow me to ride faster
> through curves the next time.

No,No NO! This is an old husband's tale!

Just as training at high altitudes improves your oxygen uptake capacity
for riding in the lowlands, you should pump your tubulars up 20-30 psi
(13.605-2.041 bar) _over_ their normal pressure for storage. This will
get them acclimated to high pressure. When you let the excess air out
to actually ride on them, they will be livelier and faster!

Carapace Completed Umber
Liège, Belgium

----------

And another, on a related topic, what to fill the tires with:

Re: CO2 tire inflators
rec.bicycles.tech 1997/02/15

redmist wrote:
>
> As far as weight and efficiency go these seem to be the way to go vs. frame
> or mini pumps. Any drawbacks?

CO2 is heavier than air, you will make your bike heavy and slow if you
use it. Helium is lighter, the only way to go if you want speed and
safety.

If you are willing to live dangerously, Hydrogen is lighter and cheaper
than Helium, but don't smoke while riding your bike if you use
Hydrogen...

Carapace Completed Umber
Lakehurst, New Jersey

[SadieKate]

It's also very important that you use CO2 cartridges filled with European air if you're using tubes made in Europe.

[CorsairMac]

It's also very important that you use CO2 cartridges filled with European air if you're using tubes made in Europe.

Wow - guess I need to find some French CO2 cartridges for my Peugeot then no?

[SadieKate]

Mais oui.

[madisongrrl]

Just as training at high altitudes improves your oxygen uptake capacity
for riding in the lowlands....

This statement is absolutely true, but what a lot of studies are pointing to now is "Train Low, Sleep High". Your recovery is severly slowed down at altitude. If you train low, you can get more training in, recover faster so you can get more training in etc.

I've been doing a lot of research on this topic because I live in Wi (flat as a pancake) and I'll be racing in at a Norba Nationals event in CO this summer (elevation 8500-10,000 feet...yikes) . So if anyone has any experience with this, I'd like to hear your stories. Perhaps I'll post this on another thread.

----------

CO2 is heavier than air, you will make your bike heavy and slow if you
use it. Helium is lighter, the only way to go if you want speed and
safety.

If you are willing to live dangerously, Hydrogen is lighter and cheaper
than Helium, but don't smoke while riding your bike if you use
Hydrogen...

Are there really people that fill their bike tires up with Hydrogen and Helium? I've never heard of this... What is the weight savings on a 40psi mountain tire Helium vs CO2 (If you are not sure, maybe I'll try to figure it out later....I on lunch, but gotta head back to work now...)

I've never heard of this, so it kinda blows my mind!

[maillotpois]

This statement is absolutely true, but what a lot of studies are pointing to now is "Train Low, Sleep High". Your recovery is severly slowed down at altitude. If you train low, you can get more training in, recover faster so you can get more training in etc.

I've been doing a lot of research on this topic because I live in Wi (flat as a pancake) and I'll be racing in at a Norba Nationals event in CO this summer (elevation 8500-10,000 feet...yikes) . So if anyone has any experience with this, I'd like to hear your stories. Perhaps I'll post this on another thread.

----------


Are there really people that fill their bike tires up with Hydrogen and Helium? I've never heard of this... What is the weight savings on a 40psi mountain tire Helium vs CO2 (If you are not sure, maybe I'll try to figure it out later....I on lunch, but gotta head back to work now...)

I've never heard of this, so it kinda blows my mind!

Um.....

As noted in my initial post, this was taken from the humorous part of Sheldon Brown's website. (I'm one for injecting a little smart aleckyness in whenever possible). I don't think any wrench would advise the Hindenberg effect on your bike tires...

[madisongrrl]

Um.....

As noted in my initial post, this was taken from the humorous part of Sheldon Brown's website. (I'm one for injecting a little smart aleckyness in whenever possible). I don't think any wrench would advise the Hindenberg effect on your bike tires...

I was wondering....I wasn't sure if the second part of your post was supposed to be humerous also or not. I wouldn't put filling bike tires up with helium past most of the weight weenies that I know!

[bcipam]

Ok checked with the "bike geek" squad. Skinny on tire pressure: Check the pressure recommend on the tire itself. Use the appropiate tubes (not all tubes are meant to be blown up to 140 psi). It is not necessary to let the air out between rides but it is important to check air pressure before a ride. A properly inflated tire means less risk of puncture and offers a smoother ride.

Mountain bike tires (wide, knobby tires between 1.9 - 2.4 " wide) generally take much less pressure. If using the bike on road or trail it can be inflated to around 40 - 45 psi but no more. On trail, singletrack etc. and depending on surface materials (ie sand, loose dirt, hard packed) use run at 25 - 35 psi. Where I ride there is alot of sand so I run my tires at approximately 30 psi. Less pressure gives you more trail "grip" but something you lose alittle control. Higher pressure gives you ability to ride faster but can be "squirrelly".

As to road bikes depends on the tire and tire size. Very high quality racing tires, at 21 - 23 cm can be run up to 140psi. normal tire pressure is 100 - 120. I used Gatorskin 25's on my road bike. I inflate them to 100 psi. They can go to 120 but I like the smoother feel of lighter pressure. Some tires, especially if they are 25's or 28's can run at 85 - 90psi. Basically the bigger the tire the lower the pressure.

Just alway remember to get a couple of things before a ride. 1) tire pressure, 2) condition of drive train and 3) proper adjustment of wheels, brakes etc.

I thank you "bike geeks" !

[DebW]

CO2 is heavier than air, you will make your bike heavy and slow if you
use it. Helium is lighter, the only way to go if you want speed and
safety.

If you are willing to live dangerously, Hydrogen is lighter and cheaper
than Helium, but don't smoke while riding your bike if you use
Hydrogen...

Carapace Completed Umber
Lakehurst, New Jersey

I did some numbers. For a 700x23c road tire inflated to 120 psig, you would add 5.5 g (0.19 oz) by inflating with CO2, and save 9.6 g (0.34 oz) inflating with helium, save 10.25 gm (0.36 oz) inflating with hydrogen (H2). Of course, one presume that if you inflate your tire with CO2 while on a ride, you were carrying the CO2 cartidge already and thus you have a net decrease in bike weight of 11 g when you use it (replacing the 11 grams of air in your tire with 16.5 grams of CO2 which you were already carrying). Compare these weight differences to carrying a pump which weighs several ounces to half a pound.