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Ok, all of you fixed-gear/ss freaks. Here's a question.(9 posts)

Ok, all of you fixed-gear/ss freaks. Here's a question.look271
Oct 9, 2002 4:59 PM
I am currently running a 42x17 but my wheel size is the old 27 inch wheels. I was thinking that I might be geared too low for a flat route, but I can sustain speeds of 18mph easily and 20-22 isn't too difficult. Think it's because of the larger diameter wheels? That would make sense, since 1 revolution would be a greater distance than a comparable 700c wheel,or should I just stop thinking and ride?=)
re: Ok, all of you fixed-gear/ss freaks. Here's a question.Mel Erickson
Oct 9, 2002 5:49 PM
That's exactly the gearing I'm going to use, except with 700c wheels. You're right, the 27" wheels make for taller gearing. Go to Sheldon Browns site,, and use his gear calculator and you'll see how different combinations compare.
Oct 9, 2002 6:04 PM
Something else for me to think about! Thanks. =)
re: Ok, all of you fixed-gear/ss freaks. Here's a question.rwbadley
Oct 9, 2002 7:58 PM
I ride the same fixed 42x17 with 700c. I think 27x1 1/4 will add about 3 inches per wheel revolution. Not alot, but some difference. If I were riding all flat without much chance of headwind I would probably look to go with 42x16 or even a bit taller like 44x16.

Think about this.MB1
Oct 10, 2002 4:24 AM
The tire matters too, and the inflation probably (and what about a worn tire vrs. a new tire).

I run big Conti Top Touring 700X25 tires on my 700C fixte wheels a lot. They appear (I have never measured it) to have a larger Outer Diameter than 27X1 tires. They sure have more rollout than the little Michelin 700X20 tires I sometimes run (and what if I run one size tire on the front and another on the back???).

Does air pressure effect O.D. and what about barometric pressure-does the change in the atmosphere change your tire size?

What happens to the tire O.D. as you wear the tread off? Does the tire get smaller as the rubber wears or does the casing stretch enough (or more) to compensate?

My head hurts....I think I'll go for a ride. I wonder what gear I am in?
It's too early in the morning for trick questions! nmdzrider
Oct 10, 2002 4:47 AM
My head hurts!!@!look271
Oct 10, 2002 7:57 AM
Ok, I just got back from doing errands on the fixie while my wife's car got inspected. Glad I wasn't thinking about this stuff then. =)
You're all ruining the simplicity of a fixie. Stop it! (nm)brider
Oct 10, 2002 7:02 AM
It's not even a 1% difference ...Humma Hah
Oct 10, 2002 1:42 PM
The rim diameter difference between 27" and 700c is something like .1 inches. There is probably more difference in tire diameter between 25 mm and 28 mm on a 700c rim.

Yeah, quit worrying and go ride. That's the beauty of fixed ... figuring out that the gearing barely matters. Adapt the motor.