Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Commuting Bicycle commuting is easier than you think, before you know it, you'll be hooked. Learn the tips, hints, equipment, safety requirements for safely riding your bike to work.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 08-02-09, 02:54 PM   #1
Cygnus67
Senior Member
Thread Starter
 
Cygnus67's Avatar
 
Join Date: Jul 2008
Location: The Flat Lands of Southern New Jersey
Bikes: Current Cannondales: 1999 F400, 2007 Road Warrior 800 . Gone, but not forgotten: 1991 SC600, 1992 M700, 1997 R500t.
Posts: 68
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
G.I. CO2 recommendation chart even close?

I had an opportunity today to use my Genuine Innovations Ultraflate Plus for the first time since I bought it a year and a half ago. It was my first flat since getting it though I'm not sure how I've managed the streak of fortune. It worked like a champ and I didn't have any issues except for (sort of) one thing. When I got home, I gave my bike the once-over and put a new tube and 12 gram cartridge back in the seat pack. Just for a wag, I checked the pressure on the tire I repaired and was quite suprised to see that it was at 60 psi. I run 700C x 25 front and back.

According to the G.I. website, a 12 gram cartridge will inflate a "27 inch road tire to 90 psi". 90 psi is about where I keep tire pressure so it seemed reasonable that this was the cartridge size of choice for my seat pack. Just to make sure I hadn't used the inflator incorrectly, I repeated the process in my garage, with the same results.

While I realize calling something a "27 inch road tire" is pretty broad and covers a lot of possible sizes, I didn't think a reasonably equivilant 700C x 25 was so much removed in size that I only got 2/3 the "rated" fill.

Where did I screw up my math?
Cygnus67 is offline   Reply With Quote
Old 08-03-09, 02:43 PM   #2
ChipSeal
www.chipsea.blogspot.com
 
ChipSeal's Avatar
 
Join Date: Mar 2007
Location: South of Dallas, Texas
Bikes: Giant OCR C0 road
Posts: 1,026
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Cygnus67 View Post
It worked like a champ and I didn't have any issues except for (sort of) one thing. When I got home, I checked the pressure on the tire I repaired and was quite surprised to see that it was at 60 psi. I run 700C x 25 front and back.
Well, now you know!

You may want to consider adding a presta/Schrader adapter to your patch kit so you can top the flatted wheel off next time.

60 PSI will get you home, won't it? I would be extra careful to avoid potholes and such to avoid pinch flats, but I doubt even that would be an issue.

I look at CO2 inflators as emergency tools, and thus rarely used. I don't expect foot-pump pressures, and adjust the post-flat part of my trip accordingly.
ChipSeal is offline   Reply With Quote
Old 08-03-09, 02:58 PM   #3
twilkins9076
TWilkins
 
Join Date: Mar 2005
Location: Springfield, MO
Bikes:
Posts: 352
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Unfortunately, I've had a bit of experience with that this year!

For me, a 12 gram cartridge will inflate a 7000 x 25 tire sufficiently to finish a ride, but not to the 110-120 psi that I normally run.

The other thing about CO2 is that it tends to leak or leach out of the tube faster than air does, so what may have felt like sufficient right after you used it may not seem nearly so by the time you get home. I think I read somewhere that the CO2 molecules are smaller than O2, but don't quote me on that.....
twilkins9076 is offline   Reply With Quote
Old 08-03-09, 03:23 PM   #4
squirtdad
Senior Member
 
squirtdad's Avatar
 
Join Date: Jul 2006
Location: San Jose (Willow Glen) Ca
Bikes: '89 Miyata 1400, '82 nishiski, 84 Torpado super strada (Cino someday)
Posts: 4,211
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 65 Post(s)
I have a frame pump, works with multiple flats and gets good pressure.


and I have probably now guaranteed I will use it on the way home today
__________________
Looking for Torpado Superlight 58cm
squirtdad is offline   Reply With Quote
Old 08-03-09, 03:31 PM   #5
Greg_R
Senior Member
 
Join Date: Jun 2008
Location: Portland, OR
Bikes: Surly LHT set up for commuting
Posts: 646
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
CO2 molecules are smaller than O2
Except you fill your tires with air, of which O2 is only 20% (almost everything else is Nitrogen).
Greg_R is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 03:09 PM.