i use a CO2 inflator with two cartridges because it can inflate a tire to around 120psi in mere seconds. i don't carry a back-up pump because if i have more than 2 flats on a commute (it's never happened, knock on wood), i can simply hop on the el or hail a cab and throw my bike in the trunk to get to work on time. i live in a city with a very comprenhensive public transit system; the idea that i would ever have to walk home with my bike because i was out of air is absurd.

I like the smaller size of the Mini Morph. It doesn't need a gauge at all. When I have to press down really hard, it's at about 90 psi, good enough for the rest of the ride.

The big advantage of the Morph pumps is their hose. The end of the pump rests on the ground, so I can press down hard, and yet there's no stress on the inner tube's valve stem. Riders have ripped the stem loose from the tube with normal pumps.

The last time I used it, I sort of counted along, and it took a lot more than 100 pump strokes to fill the tire. So it does take a few minutes at least. I only need it once or twice a year, so that's ok.

http://images.jensonusa.com/large/pu...l_______16.jpg

I live in the same city and it is not absurd. If you are at 3200N on the Lake Front Trail and have to go to 4400N/4600N, why would I walk to the street, wait for a bus/cab (A Cab can take just as long to hail sometimes) and waste more time? I can walk a mile in 15 minutes and at a little over 20 I would be home. The CTA isn't always reliable and on time. Now, if I am on the street, you are most certainly correct, and I would never consider walking because it would be counter productive.... even though I have had a few days where a walk is enjoyable but not necessary/forced. The El and cabs are also options in those situations where you have to be somewhere quick, you're a 4-5 miles away from your destination and you are even on the Lake Front Trail.

You are not left without an option if you get a flat and have no way to pump it but the comment about it being absurd to walk home in Chicago with your bike is most certainly not absurd when considering your situation.

i meant absurd in the sense that i would never be forced to walk with my bike if i didn't want to. yeah, if i got a 3rd flat on my commute and i was only 6 blocks from home, i'd just walk 10 minutes and be home instead of waiting for a train/bus or hailing a cab. but many of the other commuters in this thread say that it's necessary for them to carry a pump as a back-up in case they burn through their CO2 cartridges and are forced to walk the rest of the way to their destination. in chicago, the notion that i would ever be forced to walk with my bike to a destination because i ran out out of CO2 is absurd. there are ALWAYS other transport options that can fill the gaps in a pinch in a city like chicago.

I agree 100% and couldn't imagine living some where that I didn't have those options.

"there are ALWAYS other transport options in a city like chicago."

Must be nice.

Yep, it sure is.

+1. Practice at home. Even using four $3 cartridges is cheap compared to sitting on the side of the road staring at an empty cartridge and an empty tire. If you go with the pump, try it in the store before you buy it. All small pumps, including Road Morphs, require more effort than a floor pump. It's easy to snap a valve stem off using a pump without a hose.

I just bought a RoadMorphG and did a dry run in the comfort of my garage. Using only the tools in my seatbag kit, I dismounted the front tire, took the tube out, re-inserted it, and inflated using the minipump (my trusty Zefal Husky beckoned four feet away :) ). I even managed to remount my front tire without using the irons.

I found the Morph pump pretty good, and it inflated my mountain slicks to 70 PSI in a few minutes. It wasn't as nice as using a floor pump, but I like being able to pre-inflate the to get its shape correct before inserting it in the tire, etc. I'm willing to make the slight weight trade off.

Best of all, I am now confident I _can_ change a flat in the real world using what I carry. If anything I could probably get away with just carrying one tire iron, but they're small and plastic so I carry two. My kit includes a multi-tool, one tube, one patch kit, the morph, a chunk of old tire to use as a boot if necessary, and two $20 bills folded and taped to the top of the bag (when all else fails).

I carried CO2 carts until I got a flat on the coldest day of winter and got stuck (i.e. the dispenser froze and it wouldn't dispense - between that and my frozen hands, I couldn't get enough pressure to the tire and ended up walking).
CO2 won't give as much pressure, so you'd need to carry a few of carts.

I'd go with a regular size pump, if possible, or a mini-pump if you want to conceal it.