NiGoCo

I'm rebuilding a bike that I intend to commute on. It had a 48/38/28 set of chain rings with big heavy steel cranks and a 14-28 six speed freewheel. I had convinced myself that I was going to go to a 50/34 in the front with a 14-34 seven speed freewheel in the back.

Now I'm second guessing that. The route is mostly flat with some slight grades but nothing significant. If I stick with a 48/38/28 up front I would go with a 14-28 seven speed freewheel.

Would I be giving up too much going to a double?

old's'cool

My advice is suit yourself. You will get all kinds of differing opinions with your question.
Use logic and be prepared to experiment iteratively to find what suits you best.

caloso

If you go from a 48/38/28 triple with a 14-28 freewheel to a 50/34 double with a 14-34 freewheel, your lowest gear will be exactly the same (1:1). So, I don't think you're giving anything up.

NiGoCo

Right, I would keep the 1:1 low but have a slightly taller top gear @ 3.57 vs. 3.42. Looking at the ratios I don't see any real big holes missing between the two, just less overlap in the double vs. the triple. I guess the only real difference is slightly less weight by loosing one chainring.

Darth Lefty 

I usually love a good gearing thread but in this case it sounds like you're about to buy a crankset that costs more than your bike did.

SactoDoug

You will hardly notice the weight difference from one chain ring. You could switch to aluminum cranks and save just as much or more weight.

I recently switched from a 48/38/28 to a 46/36/26 with a 12-34 cassette. The main reason for my switch was to go from 170mm cranks to 165mm cranks. I like the slightly smaller gears with shorter cranks since it lets me use a higher cadence. It had the added benefit of being about a 1/2# lighter due to being a higher quality part.

CliffordK

What are you riding now? Previously riding?

I'd encourage you to start paying attention to what gears you actually are using.

So, if you are rolling in the 48x11 a lot, then consider something bigger. If not, then don't bother.

Likewise, if you're rolling in the big ring most of the time, then there may be no need for a triple or a 30+ tooth cassette.

Personally, I find that carrying or pulling cargo chews up the gears quickly. But, otherwise, I just don't really need or want extremely low gearing.

I suppose you might also want to consider if your commuter is a multi-purpose bike. For example, do you wish to take for loaded touring?

NiGoCo

Well the bike was $20 so it would be hard to find a crankset that costs less
It's getting changed for aluminum regardless.

I'm not riding anything now. My only other bike I converted to a single speed but it's broken at the moment.

clengman

I would just ride it as is and see what gears you use most before changing anything. I have had gearing setups that didn't look great on paper, but there was one ratio that was just right for cruising that I used 70% of the time. When I switched to a different setup (had to replace some worn out parts) that looked similar on paper, it jumped right over that ratio that I really liked, so 50% of the time I felt like I was either spinning out or bogging down. Also think about where your most frequent shifts happen. If, for instance, you like running up and down the gears in the middle ring while cruising on level ground, you might find that a compact double changes your shift pattern and will require more frequent shifts in the front.

Also... What kind of bike is it? Why do you need an alloy crankset? I have a bike with a pressed steel "tourney" 48/38/28 crankset. It may not be pretty, but it's pretty bullet proof. I'm not changing it for anything until it's damaged or worn out. Then I'll buy the same thing again for what? $25? It has worked fine for 20 years.

NiGoCo

The bike is a German bike by the name of Fischer. It was purchased in Germany by the gentleman I bought it from. And he used it for transportation around the various military bases he was stationed at.

The bike is currently torn down to the bare frame. So starting out the drivetrain will be all new components. I'd have to look in my notes to verify but the stock crank arms and chain rings are as near as makes no difference 8lbs, while probably indestructible I feel that's excessive. I'm putting a new crank set on it not only because the original chain rings are pretty worn but also to reduce weight. I'm more than fine with steel chainrings, maybe I wasn't very clear earlier. But it's getting alloy crank arms.

wphamilton

Even the spacing difference is mainly just the bailout gear, right? 14-28 vs 14-34. So unless that's important, and you have the same low gear ratio, why prefer a triple at all? Go with the compact double.

clengman

That makes more sense then. Sounds like a cool project!

CliffordK

Everything about your commute sounds pretty mediocre. A few gears are nice, but you really don't have to go overboard.

I suppose I grew up in an era when the average bike would have say 52/42 chainrings and a 13/21 freewheel.

As I've grown older, I had to cheat a bit, and went with a super small 41T chainring on my old bike.

Ok, so I do mash, and am not a strong spinner. I do believe my cadence is evolving. I still like to stand and power over those overpasses and small hills.

For my more modern bike, I would be riding a "standard" crankset, except for an intense hill ride up in Portland that forced me to a mid/compact 53/34 up front with a low gear of 23 in the rear.

I'll pull a trailer with most of my bikes, but have chosen to experiment with lower gearing just for heavy cargo and steep hills.

Anyway, if you are spinning 100 RPM at the slowest, then that 1:1 gearing may be good. Otherwise, it just seems awfully low.

Anyway, what I'd do is to build your bike back up with the parts you have on hand. Then experiment a bit, and watch what gears you naturally choose.

If you are always riding pegged in the top gear, then look for some more high end range. If you are riding a lot dropped down to the small triple, then work on the low end range.

An option is to use your triple as an escape configuration. Most of the time use it as a double, but keep the option open for that third sprocket once in a blue moon.

NiGoCo

I probably should have rode it more prior to tearing it down. Unfortunately once I aired up the tubes the tires started to split from being dry rotted. I rode it around the block once then called it quits. Everything was pretty crusty so I just tore into it.

The reason for the question and why I'm debating is that I haven't really been on a bike for close to fifteen years. I tore up both knees at work and had to give up riding. My green bike, which I have been riding for the past three years just gently around the neighborhood is a single speed. Now that I've got my knees back I want to get back to commuting. I'll start a new thread with more details about the bike.

noglider 

I say don't change anything until you've ridden it a fair bit. Unless your route is very hilly, you probably have far more gears than you need. But that doesn't mean you should change them.

wphamilton

FWIW when I've swapped a massively heavy triple for a standard or double, I did appreciate the difference in weight and felt it was a worthwhile, and permanent, change.

NiGoCo

I guess it wouldn't hurt anything to throw the original stuff back on it. Except the part of me that can't stand the thought of reusing parts I had already planned on replacing.

nfmisso

For my relatively level commute of ten miles, with 35-622 tires, I like a 44T chain ring with a 12-36 9 speed cassette. I need the 44-36 combination for on particularly steep but short grade. On the level, we a 15mph tail wind, the 44-12 combination is good, but could be a fraction taller.. Without wind, on the level I am down a couple gears from top.

noglider 

Sorry, I wasn't clear enough. Replace the freewheel/cassette if you're inclined, but use the same gearing until you know changing it makes sense.

Gresp15C

I think given the uncertain condition of your knees, you can't have too many gears, and you can change your gearing later.

NiGoCo

You know, that does make a lot of sense. I haven't really put them to the test so to speak.

Thank you everyone for posting. You've given me several things to consider.

I may just put it back together and test it out for a couple weeks just to see if it's actually going to be feasible or if my knees tell me it's a really bad idea over the long haul.

wphamilton

Imminently reasonable, but keep that compact double in the shopping cart. On some sites, the price sometimes drops to prod you to pull the trigger on it.

Bike Gremlin

I'd recommend this "tool" for figuring the gearing out:
https://gear-calculator.com/

From my experience, with a cassette that starts at 14 T, you're fine with a 50-34. If, however, you switch to an 8+ speed cassettes, they are expensive in such "exotic" setup. Usually starting with 11, or max 12 teeth. Such cassette with 50-34 cranks on the flats usually results in riding severely cross chained. Either using the few smallest cogs from the small chainring, or the few largest from the large chainring.

28-38-48 chainring setup is very versatile and I'd consider getting a good quality cranks with similar setup.

aggiegrads

NiGoCo

I'm in Temple. I live south and work North. I would call it flat but I came here from East TN, an Cincy before that.