Triple chainrings, what's the big deal???



Bob Ross said:
Here's an observation which rarely comes up in the compact double versus triple discussions:

Depending on your cruising speeds, a triple may actually allow more efficient shifting.

I'm riding a compact double (50/34) with a 12-27 in the back. For climbing it is awesome, and I can get up nearly anything I could get up in a triple with almost as much ease.

But on the flats when cruising between 18-20mph, I find I'm always switching between the 50 w/ mid-to-large cogs, and the 34 w/ mid-to-small cogs; at that particular speed (where a lot of the club rides I do happen to wind up) it falls right on the cusp between chainrings. Whereas when I ride a 52/39/30 triple I can pretty much leave it in the 39 to maintain that speed.

(Obvious solution: go faster!)

These are good observations. I think that for certain types of riders--one who can cruise in the 20 mph range and rides a high cadence (90+), that a compact means a lot of front shifting as a lot of the riding is done in that 60-80 gear inch range.
 
Then there's the old-fashioned way of getting a wide range of gears:

My 1980 Raleigh has 52 and 42 chain rings, and the five speed freewheel is a 14-18(17?)-23-30-34. (Or as they used to call it, an "alpine" freewheel.)

(Don't ask me why "2nd gear" wasn't more evenly spaced.)

Even with that low of a cog, I've still been tempted to change my 42 ring for a 40. (Hey, I live in a hilly area, my bike's not that light, and neither am I.)

Basically, when I'm riding in a more or less flat area, I'm in the 52 ring, and just using 2 or 3 of the cogs. With so few gears, my speed is adjusted in 5 mph increments... (The 42 ring is more or less used for starting up from lights, and for when I hit hills.)
 
Bikelyst said:
Ok, I am curious, why is a double better for racing?

This is from my own experience - it really does take longer to shift a triple, not so much that if you are not competing that it matters, but in a race it only takes a seconds hesitation for a gap to form and voila you didn't make the break. So OK don't use the small ring.... well then you are using a 42 as your small ring, which is a whole lot harder than using a 39. Until I got a new bike I took care of it by swapping my 42 for a 39 and locking out the 30. Now I have a new bike with a double and I'm much happier.
 
I always get a chuckle out of the road biker gang's gears. They have what look like fairly big chain rings AND really small cogs. Then I look at my touring bike. I don't even have to wipe of my 52 tooth chain ring. I can't imagine using it, and I have 11/32 cogs on the back. I try not to call myself slow, I say I'm enjoying the scenery ;)

Seriously, I do fully loaded touring so the more granny the better for me. I would have expected I would appreciate a wider gear range on a touring bike but I only use the smaller 2 chain rings in the front. Above 22 mph or so I don't ever pedal. If I pedaled up to 30 mph I would probably use teh 3rd ring.
 
Eden said:
This is from my own experience - it really does take longer to shift a triple, not so much that if you are not competing that it matters, but in a race it only takes a seconds hesitation for a gap to form and voila you didn't make the break. So OK don't use the small ring.... well then you are using a 42 as your small ring, which is a whole lot harder than using a 39. Until I got a new bike I took care of it by swapping my 42 for a 39 and locking out the 30. Now I have a new bike with a double and I'm much happier.
I actually prefer the 42 over the 39, seems to reduce the switching between rings. I assume you mean a hilly race, as with the flatter ones, I would be on the 53 all the way.
 
mikesbytes said:
I actually prefer the 42 over the 39, seems to reduce the switching between rings. I assume you mean a hilly race, as with the flatter ones, I would be on the 53 all the way.

Yeah - out here generally most of the road races have at least one good hill in them that splits the field and some are downright mountainous - which is good for me though cause I'm much better on the hills than I am on the flats and I prefer small sprints over huge field sprints..... I'm not big or strong enought to really want to push a 42 though I did it for most of the early season last year, before I got my new bike. I didn't hurt myself, but it didn't make climbing any easier or faster for me either. Now I can hold a better cadence - don't have to slog so much. We can get some pretty steep grades out on course here - 18 20%ers for short stretches at a few races.
 
I know what you mean on the road the 52 doesn't get used much. OTOH on the indoor trainer I use it all the time because shifting chain rings on the trainer causes a big drop in speed. Small cogs with close ratios is also helpful on the trainer when you improve enough in the 21T at 97rpm you don't want the next choice to be 18T at about 84rpm. That's why I have a custom cassette with fairly close ratios.


rcrampton said:
I always get a chuckle out of the road biker gang's gears. They have what look like fairly big chain rings AND really small cogs. Then I look at my touring bike. I don't even have to wipe of my 52 tooth chain ring. I can't imagine using it, and I have 11/32 cogs on the back. I try not to call myself slow, I say I'm enjoying the scenery ;)

Seriously, I do fully loaded touring so the more granny the better for me. I would have expected I would appreciate a wider gear range on a touring bike but I only use the smaller 2 chain rings in the front. Above 22 mph or so I don't ever pedal. If I pedaled up to 30 mph I would probably use teh 3rd ring.