Same Gear Ratio - Bigger/Bigger or Smaller/ Smaller (chainring/cog)
 

44/16 (ratio of 2.75)
47/17 (ratio of 2.76)
50/18 (ratio of 2.78)
52/19 (ratio of 2.74)

So all are almost the exact same ratio. If one wants to maintain the same gear ratio (skid patches don't matter as the bike would be freewheeling, not fixed), what are the pro's and con's of going Bigger/Bigger vs Smaller/Smaller for street riding?

Tests have shown larger rings and cogs to be slightly more efficient. They also last longer because they don't wear as fast as smaller ones do. The only drawback, and it's a small one in my opinion, is they are slightly heavier.

Other than the slight efficiency and wear advantages @AlmostTrick notes, if you do skid stops, a ring and/or sprocket with a prime number tooth count will give you the maximum possible number of skid patches, so 47/17 or 52/19 would be the preferred combinations of those you are considering.

Small: slightly less weight. Slightly less frontal area for wind resistance. Slightly less chance of clonking the chain ring if you ride across badly broken ground. Slightly more wear, slightly less efficient.

Big: slightly heavier, slightly more wind resistance. Less wear, and slightly more efficient.

Most of us in every day riding would not notice the difference, but might make the choice on aesthetic grounds, or just on the basis of what's available.

I run 47t on of my bikes, keeps it simple.

Thanks for all the feedback!

I run smaller. No real reason until I had my custom made. On it, I can run any cog between 12 and 24 teeth without messing with chain links. A 42 up front gives me the option of true mountain gearing; 42/24 = 47 gear inches and 42-12 gives 95". (At least this was true mountain gearing for my first 2/3s of a century. One century being one hundred years, not miles :))

Ben

Although it's probably rare, some frames don't have enough chainstay clearance to run big chainrings with a 42mm chainline. My FG-converted mountain bike limits me to a 45T ring, for example. Not the end of the world, though!

I run 48t/16t on my Aventon Cordoba, and 46T/16t on my State Bicycle. I prefer he 48t because I spin out too easily on the 46t. Even thinking of going to a 50t.

Do you live in a perfectly flat town? 46/16 @ 120 rpms is like 26 MPH!

Started out in Florida then moved to a small town on the West Slope of Colorado, and it's mostly flat with some small inclines and hills. In either place I actually get higher top speeds and average speeds with the 48T/16T. State Bicycle by default gives 46T/16T on their 4130 Cromo's but I spin out those eventually.

I’m with you, VS3! I started out 46:16 and spun out too. Upped the chainring to 48 and find this to be ok for now. Average cadence is 80. Keeps me around 20mph. I would like to try 50T chainring or 14T freewheel gear to up my average speed. I ride in and around Bradenton/Sarasota Florida

HLaudio, I've been curious about a 50T myself. Approaching the point where 48T may be too easy as well. But it's also good for moderate hills, so I've been hesitant. Stay safe. We both know Florida is not pedestrian or bicycle friendly for the most part. Although I moved last Winter after 14 years in Riverview, I recommend Critical Mass in downtown Tampa if you ever get a chance. Check them out on MeetUp. Friendly group of riders, with numbers around 140 cyclist.

You guys are spinning out at 26+ MPH for more than a few minutes at a time? For how long? I picked up almost 2 MPH by lowering my gearing and actually spinning out. My Max mph is lower, but I am faster by spinning than by mashing. Even onp perfectly flat terrain.

On certain descents yes, plus even on flats it's just too easy and I don't like my cadence that high. The 48T keeps me around 78 to 80.

For me it’s not about spinning out, it’s about higher average speed My average cadence is much like VS3, 78-83. Im fairly certain that if I up the chainring I’ll increase my average speed , IF I can keep the average cadence above 80. I ride flat with the occasional drawbridge approach. Before the virus lockdown I was riding 20miles round trip to restaurant job 5-6 days a week. Now I’m riding 20mile workouts 3-4 days a week. Basically I would like to up my average speed.

Do you guys have Strava or tracking data showing that your average speed is higher with such a low cadence? Your top speed might be higher, but at 80-90 rpm, you're at 21 mph. I'm at about 68 gi and at 120 rpm where I would be at 25 MPH. I believe this to be a "feeling" rather than actual speed. I average that 21 without spinning out and also can mange hills and unpaved terrain. I'm a large man, and can mash with the best of them, but if I track a ride on Strava or mapmyride I am never faster at 80 gear inches than I am at 68 gear inches unless it's a short ride with me sprinting the entire time on a flat route. Average would be higher with lower gi and higher cadence than with higher hi and lower cadence.

Yes, I Strava and Samsung Health when I do turn them on. But why does it matter? What are you, the cadence and sprocket police? Each rider has their OWN comfort zone, regardless what some chart says about gearing size, cadence and MPH. I don't like 46T because it's too "easy" for me and gives me a higher cadence. Or a slower cadence and therefore slower speed. My comfort zone is my 48T. It also depends on what I feel like doing when I ride, and if my wife is with me, which means I am definitely going to be riding slower for the most part. You're size and who YOU can mash with is irrelevant to me.

​​​​Yet to make you feel better, the first image is 46T/16T with my State Bicycle Pardi Boi. The next two are 48T/16T on my Aventon Cordoba Polish:

https://cimg6.ibsrv.net/gimg/bikefor...430dec1f67.jpg
https://cimg3.ibsrv.net/gimg/bikefor...177e75bd38.jpg
https://cimg9.ibsrv.net/gimg/bikefor...29821a050b.jpg

I've done a timed 45 minute event at an average speed of 18.6 mph, (twice) on my 46-18 (68 gear inches) with NO drafting. This meant an average 92 rpm cadence. A higher gear would have been slower for me. YMMV

I understand that everyone's preference differs, but I'm convinced that many, maybe even most SS/FG riders are over geared, and can often be found lugging that gear at relatively low cadence. (and speed) Most riders are not averaging 20+ mph.

Senrab62... full disclosure about me and my bike!

I am 65yrs young, 175lbs and 5’10” tall. I ride a Pure Cycles steel single speed with WTB 700-28c ThickSlick tires, front & rear Tektro rim brakes, levers mounted on 420mm bullhorn handlebars. Cranks are 170mm with Wellgo platform pedals driving a 48T chainring to a 16T freewheel gear, chain is 1/8” x 1/2” link.

I am not allowed to post photos just yet because I don't have enough posts on BF. So I will quote my info from my Wahoo as shown on my iPhone ...today I rode 7.86 miles, ave speed 20.8 mph, top speed 25.4mph, moving time is 22:42 min, ave cadence 86rpm max cadence 107rpm, wind was 14mph out of the NW. Half of my ride was into the wind.

Although I’m ok with the 48T chainring, I’m thinking 50T maybe a bit more comfortable. My goal is consistent cadence with best average speed. I use my bike for two purposes, transportation to and from work and quick simple workouts. I rarely ride for pleasure, unless my brother should visit once in a blue moon!

I’ll gladly post photos when I reach the 10 post mark.

H

BTW... I use BikeCalc.com for estimates only. However, I have found it to be fairly accurate. My 107rpm = 25.4mph. My average cadence of 86 = 20.8mph same as BikeCalc!

Way to move man! Outstanding!

Here's shots of my Aventon Cordoba when I first got it, and now. Plus my State Bicycle Pardi Boi.

https://cimg2.ibsrv.net/gimg/bikefor...c4911f60b7.jpg
https://cimg9.ibsrv.net/gimg/bikefor...482438e146.jpg
https://cimg1.ibsrv.net/gimg/bikefor...690e4afc4f.jpg

Thank you. The lower gi is faster on that similar route if I am understanding correctly.

I am not trying to cause an argument here, just wanted to ensure that we are not relying on anecdotal evidence as facts. I understand top speed, but again, I have much more versatility with a moderate go versus a high gi. Add any hills, and moderate is faster every time. I have never seen any evidence of anything else, 3rd party nor personal experience so I just am trying to keep this fact based.

Ultimately, go ride your bike! I was not trying to be negative. 👍🏾💪🏾

Apologies bro. Offense is often taken and not given. Taking my IT WFH workload out on you as I send User's home. I appreciate your time and input.

No need for apologies! We're all here for the same reason. Another reason I advocate so strongly for appropriate gearing is also because I have had ACL reconstruction on both knees due to football injuries. Long term knee health is a huge consideration for me as well.

Spinning is not for everyone, and I am still trying to improve every time I ride. I am extra fat and slow so take my advise with a grain of kosher salt 🤣