Okay it might be great for someone who doesn't want to ever go near 30mph but it doesn't work for me. I had to replace my rear cog(15t) a few days ago to a 16t(already had it). It's a dura ace cog and lock ring. Should I buy another rear cog and lock ring? Or should I buy a new 52t chain ring?

If you like 48/15, then I would go back to it. You will save having to change the chain.

Learn to spin.

In addition to what bmwjoe said, combining odd and even toothed cogs and chainrings gives you more skid patches if thats something that you get up to. So if you like to stick around 85 gear inches then I'd say 48/15 is better than 52/16.

If you use brakes then I think its actually the opposite (?). I think even toothed setups put more even stresses on the chain (or something like that, somebody help me out here).

In any case it shouldnt make a huge difference in practice.

Also yeah, 85 is uncomfortably high of you ask me. Maybe I'm just a wimp though .

48x15 (or 16 for that matter) might work for someone super crazy strong, or more likely, someone who only mashes.

30mph? I can top that with my 46x18.

I'd rather spin at 30mph+ than 20mph

48/15 brakeless is what I've ridden everyday for the past 3+ years

You need to find your "sweet spot" in terms of Gear Inches.

Use the calculator https://www.sheldonbrown.com/gear-calc.html

From experience, my sweet spot is around 60-65, any lower I'm spinning, any higher I'm mashing.

Good luck.

The ancient rule was that you never used a gear that was an integer ratio for a fix gear. 48/16 = 3; an integer. This means that the relationship between your chainring and cog comes up exactly the same every pedal stroke. 48:15, o issues. 49:16 is OK. 52:17 is virtually exactly the same gear as 48:16; just far enough off to be not exact.

I haven't ridden a gear that high since I was a first year racer 40 years ago. Listened to the club vets and moved it down the next year and got serious. So I have very l;imited experience on intrger ratios. A little on a 42:21 but that was virtually all on major climbs. Harmonic issues at those RPMs wasn't happening!

Ben

No use arguing over how someone likes to ride their bike. If a gear ratio that high works for you and you enjoy it then more power to you. That said, larger gear ratios don't necessarily mean that you go faster; and from my experience, faster is not always better.

In my case, I actually changed my gear ratio around quite a bit when I first started riding. I lived in Pittsburgh at the time (crazy hilly) and I wasn't a very strong rider so I went down from the stock 46/16 of my first bike. By the time I moved to Chicago (flat as a pancake), I was a much stronger rider so I initially thought my ratio was too low. However, winter came and the wind killed me on my commute (which was much further here than in pittsburgh). I ended up gearing down again just to get through the winter. I felt like an absolute slug at first, honestly. But by the time spring came I was making record time to work on like low 60s gear inches. I almost didn't even gear back up. Weirdly, it took until I tried that ratio, even after years of comfortably riding higher ratios, to find a cadence and rhythm that really made me feel one with the bike rather than just riding it (if that makes sense). Since then I've geared up again to the mid 70s but can still click into that magic rythm!

Long story short, changing your gearing always feels weird if you only ever ride one ratio. I think exploring smaller ratios can be super beneficial as a rider though, if only temporarily.

TLDR:

No way 85 gear inches is faster unless totally flat and never any wind. I picked up speed on one of my fixed gear bikes by going from mid 70s to just under 70 just this past summer. Spin to win!

When you are young or not experienced mashing a big gi feels faster but never is. Perhaps the op doesn't ride for distance or in the wind often so this setup works for him?

I live in south Florida. It's flat as can be. I do mash everywhere I go. I do have strong legs. I don't see the point of spinning out at 20 mph for no reason. Top speed is important to me. 85 Gear inches is literally faster. It's just math.

You're averaging 120+ rpms or so at 85 gi for extended periods of time with head/crosswinds?

Forget about any times for the fastest descent anywhere.

I like to mash a 52:16 but mostly stay on flat sections around DFW.
For sure need some other gears if Im doing any hills.
The SS forces me to get off the saddle often which my @@$ really enjoys.

QUOTE=ryan_rides;21289015]Okay it might be great for someone who doesn't want to ever go near 30mph but it doesn't work for me. I had to replace my rear cog(15t) a few days ago to a 16t(already had it). It's a dura ace cog and lock ring. Should I buy another rear cog and lock ring? Or should I buy a new 52t chain ring?[/QUOTE]

A lockring is a lockring. Cog doesn't matter. It just needs to match your hub threads. No need to get another. (Exception - if you are going to very small cogs, ie 12 teeth; then you need a bell shaped lockring so the chain doesn't ride up on it.)

Eur-Asian cogs are just as good as Dura Ace and might be cheaper or easier to get.

Ben

48/16 would suck for me as well, but for different reasons. I just prefer the way a smaller gear spins up faster after stopping at an intersection. Which I do nearly every time, like a lame normie.

So what kind of distances are you riding 30mph? lol

Are you riding brakeless? Locking your legs with big gears can mess you up, I suggest you to start spinning faster.

really depends on where you are riding....48 x 17 here, it's hilly where I have been riding lately and I am old.. If it was flat as a pancake I would go 15/16 Have done 600 +miles on the fixie this year.

If you can’t spin @30mph with 48:16, you don’t know how to pedal. Your problem is not your gear ratio, it’s your poor spinning technique.

Hello mihlbach!

could you please explain “If you can’t spin @30mph with 48:16, you don’t know how to pedal. Your problem is not your gear ratio, it’s your poor spinning technique.”

I don’t understand how “spinning” is efficient? I think I understand ryan_rides desire is like mine, to increase average speed. I ride to commute to work, 20 miles round trip and for exercise, 8 - 25 miles. And like ryan_rides, I too ride the flats of Florida. Our biggest challenge is wind and drawbridge approaches.

thanks!
H

Dang, total n00b here running 46/17. My lil legs would probably have a hard time starting from stop signs and lights at 46/16 or 15.
I've got a 48t Sugino RD2 I just took off another bike but I'm saving it for another SS/fixed build.

High efficiency isn't necessarily the reason for choosing a particular cadence and cadence is only one variable that dictates your efficiency. Pedaling smoothness and your own personal fitness are more important factors. A cyclist with good pedaling technique can efficiently spin a reasonably high cadence for a prolonged period of time. You aren't gonna find many experienced cyclists (including FG riders) mashing an average gear ratio higher than 48:16 unless they are very strong cyclists who are interested in maintaining very high speeds (e.g. racing). Your cadence is going to vary wildly with a SS or FG. Being able to cruise a higher cadences prevents muscle fatigue and trains your legs to work effectively at a wide range of cadences. Mashing a high gear increases your potential top speed, but your top speed is only sustainable for a tiny fragment of an entire ride. When you start adding traffic lights, traffic, hills and other variables that inevitably slow you down, a smaller gear ratio gives better acceleration, and allows you to keep on top of your gear when climbing. Lower gears also enhance your ability to modulate speed if riding brakeless.
Most experienced FG riders are going to recommend a gear ratio in the low-mid 70s for average riding conditions, with some small deviation from that range for exceptional conditions (hills, rough terrain, etc.). The ratio of 48:16 mentioned by the OP is approaching 80 gear inches. Its on the high side of the normal range for street riding. Any decent cyclist ought to be able to easily spin that gear @30 mph. Even at my physical prime when I could hang with the fastest of roadies, I never ran a gear higher than 80 gear inches, and most often rode 49:17 (which is about 75-76 inches depending on the tire size). Higher gears, while great for short bouts of speed, did not increase my cruising speed and they had a diminishing effect on my average speeds, again because I could not accelerate as quickly and could not maintain speed on steep hills.
No normal human is going to be cruising along at 30 MPH, except, as I said, in situations where the cyclist is intending to go fast for short distances. So if someone feels this gear is too low (as the OP has bragged), it is not an indication of strength. It is an indication that they don't know how to pedal.

Thanks! mihlbach!
Thanks for taking the time to reply. I appreciate your knowledge and I can now apply this to my riding technique.
Cheers! H