tara1234

Hey so I have to replace the chainrings soon on my road bike as the big ring is bent meaning I have to use the "small" ring which is 42t.

However what i have noticed after learning to spin is that even on the small ring I am rarely needing a higher gear.

Now should I go for a compact road or mtb double or triple as my 42t is high enough for me or will I outgrow it soon, meaning a compact double or road triple.

Also wondering if triple with a closer ratio would allow me to maintain a better cadence.

My shifters: downtube full friction.

My rear gears: 11, 12, 15, 18, 21, 25, 28, 32

52telecaster

42-11 would always be high enough for me, but i am 60 years old. so ymmv. a compact double with 34-42 or more would give you much lower gears for climbing. its difficult to say if the derailleur would work with the new crank.

supton

For a while I thought of not fixing the FD on my road bike; the 42T chainring did 95% of my riding, and I could deal with the other 5%. I still like having a triple on it, with a narrow range cassette. The 30T is rarely used--but when it's needed, it's needed!--and the 52T is for bombing down hills.

Really depends upon what you want, and where you ride. You might want a more narrow range cassette (freewheel?) if you want better control on cadence (less change between gears). If you don't have big hills to contend with you could try doing a half-step setup, with a 36-42 (for example, or 42-47?) set of chainrings, with the idea being, you can fill in the gaps on your existing cassette by using the front.

I did recently try out a compact, and it's definitely different, as a front shift is 3+ gears (compared to the rear). But it's not as bad as I feared: as long as I am maintaining a good clip, I really only need the small ring for hills above a certain level. But I think that's the trick: on a slower bike it might not be so hot. YMMV.

Retro Grouch 

I think that the trick to a compact double has to do with your favorite flat road gear. You'd like for that combination to fall in the middle of the cassette. That way you have a couple of trim gears in each direction without having to make a front gear change.

grayEZrider

After a couple of years riding several ten, twelve and 24 speed road bikes I think I might be able to do a 1 X 9 or even 1X8. I like the idea of the simplicity of it. I'm thinking of changing out an '82 Nishiki to maybe a 44 x 11 > 34. Any experience or thoughts on this?

supton

What does it cost to try? Might be a deciding factor for both questions.

Only thing issue I can think of is chainline (for the 1x). Which may work either way: you could center it, or you could offset in the direction of most use (like reusing an existing crank). Only problem is, running 1x's is chain retention. Have to use a specific chainring, or leave the FD on.

grayEZrider

Thanks. I've got a sixties Royce-Union (later named American Eagle- later still Nishiki) I can fool around with to test gearing range first as a 1X5 then worry about alignment. At 66 I'm not too concerned with cadence.
Just getting up the mountain and home without pushing is a good day.

BlazingPedals

My gearing strategy is like Retro says. In addition, I believe that if you can obtain identical gears in both chainrings, the one using the bigger ring will be the most efficient. So I usually stay in my big ring and stay away from the 11-13T gears in back since they waste power. They're only for downhills or all-out (short) sprints. If you're 'surviving' your 42T-only system by using your 11 and 12T gears, you'll see an improvement in overall speed by giving yourself back a big ring and using it.

What gears you get depends on how unhappy you are with the current setup and how much you're willing to spend. Just replacing your big ring with a 50T leaves you with duplicates in lock-step for all but first and second in the small ring and the 11T in the big ring. That would be Bad. Replacing the 52T with another 52T only leaves you with a couple of duplicates (having some is almost unavoidable.) Going to a compact will give you a nicer spread of gears but will cost a lot more $$$ since you have to buy a new crankset. A triple may be the costliest since you may have to also replace the front derailleur, too.

Phil_gretz

So your downshift steps are 9%, 25%, 20%, 16%, 23% 25%, 14%. I really don't like this cassette much. Why not a 13-26T, with 13.14.15.17.19.21.23.26. Now the jumps would be 8%, 7%, 14%, 13%, 11% 10%, 12%...tighter. That way, you can position where the overlaps are. I'm not using a gearing calculator, but I might try 42T and 46T on the outer ring. Nearly half step gearing and a 94 to 42 gear inch range. Perfectly serviceable. Play with a calculator and minimize wasted gears...

berner

This arrangement makes sense to me also. Tara, I think you are on the right track looking for gears that promote spinning.
Bern

WizardOfBoz

One thing to note (admittedly pretty minor) is that chain efficiency is lower when the chainrings and cogs are smaller. So a 42-11 has lower efficiency than a 52-13, even though the ratio is the same. If you have the big front ring, you can sometimes choose the more efficient pairing.

I don't know your demographics (age, sex, weight, etc.) or your genetics (descended from a family of Swiss Mountain climbers who later all became Olympic champions?, etc.) or your history of bike riding. But I'm older (near 60), heavy (240lb) and my legs aren't what they once were. I ride a 52-36, and use both fronts. My personal land-speed record is over 43mph. That would be hard to spin with a 44.

tara1234

What exactly is chainline efficiency? Will it be that a 42x11 will wear the cogs down quicker than a 52/13 or will the 52/13 be easier to pedal?

alcjphil

Both actually. 11 tooth cogs wear much quicker than 13 tooth cogs, almost twice as fast. As well, a chain has to bend more to fit an 11 tooth cog than a 13 tooth cog, and using the small ring/small cog combination means that the chain will be engaging the teeth at an angle causing friction

BlazingPedals

In addition, your legs provide the energy to wear down the 11T - and your chain - faster. You see it in extra effort to go a particular speed as well as prematurely-worn parts.