Triple vs. compact gearing?

loinnsigh

I'm looking to buy my first road bike - up to now I've been using an old steel frame MTB for my runs up around the Wicklow hills (which is where I live).
I'm 65kg and at a reasonable fitness level.

My question is - should I go for a triple or compact crankset? I'll be doing a mix of flat (commuting) and hills (weekends, sportives etc). There seems to be less choice of bikes available with triples, and all the bikes I prefer seem to be compacts.
Do I need the Granny ring?

I've been around a good few bike shops at this stage and have had conflicting advice from each one. Head is melted

Lumen

A 65kg man with reasonable fitness should not need a triple.

fat bloke

loinnsigh wrote: »

I've been using an old steel frame MTB for my runs up around the Wicklow hills ....I'm 65kg

Would it be fair to say those two things are not in related!?

If, at 65kg, you've hitherto been comfortable pushing an old mountain bike up-Wicklow-hill and down-Wicklow-dale, fcuk me man. That's impressive!

I was all set for a "triples make a lot of sense starting out" sort of post but Lumen is spot on there. Go buy the bike you like.

johnk123

I got a Giant Defy 3 as my first road bike and the front derailleur doesn't get much action on the small ring... and I'm a couple kilos heavier than you. I suppose it was nice to have when starting out, gives you and idea of the range of gears on your bike etc but I won't be going for one again.

Surveyor11

Like johnk123, I had a Giant SCR with a triple. Handy when starting out, but found myself more and more on the middle ring and that granny gathering dust as I got fitter. Have now got a compact - the gearing can be just as low as a triple anyway. The one thing that annoys me about triples is the amount of adjustment to keep them working. Looks like you would have no issues on a compact if you've been hoofing up in that tank!

happytramp

I don't know if it's true but I heard that girls find guys with triples are a MASSIVE turn off.

triggermortis

happytramp wrote: »

I don't know if it's true but I heard that girls find guys with triples are a MASSIVE turn off.

I know this to be true. My wife could barely stand the sight of me when I rode a triple but as soon as I got a compact..BOOM, she's pregnant!

Roadtoad

(a) I confidently expect that I'm in the second half of my life, and
(b) I'm 50% heavier than the OP
(c) I've walked up Mahon Falls once too often.

Done all the parenting thing too, so from now on all my riding is purely recreational.

kincsem

A triple is a 52/39 standard setup with an extra chainring. However, that small chainring weighs about 10 kg, and slows the switching between front chainrings significantly. Everyone knows you only change gear at the front rings. And a triple is embarrassing to own.
HTH.

Beasty

triggermortis wrote: »

I know this to be true. My wife could barely stand the sight of me when I rode a triple but as soon as I got a compact..BOOM, she's pregnant!

That's because you spent more time outside riding, and she spent more time inside ri...

smacl

I'd say go for the compact but get it with a large enough cassette, e.g. 28t, to make hills comfortable without having to get out of the saddle. I picked up a second hand road bike with triple at the from and 12/23t at the back which is actually ends up with higher gain ratio lowest gear (30/23 = 2.5 gain) than many compacts (34/28 = 2.4 gain). Check Sheldon browns gear calculator for more info.

Plan is to ditch the triple for a compact groupset once funds become available, but still keep a nice low gear in reserve for those ramps at the end of long days. I would have really liked a few more teeth in the cassette last weekend going up lovers leap.

T954

Go compact

youtheman

My first bike had a triple, and when I was going to purchase my second (carbon) bike I had a good look at the issue of gearing. It's not the number of gears that is important, it's the gearing ratios that is important. When you are in a given gear the ratio is (number of teeth on front cog) divided by (number of teeth on rear cassette).

For example my old bike was a triple with 50/39/30 teeth on the front cog with a rear casette with 25/12 teeth on the back. So the biggest gearing ratio (for speed) was 50/12=4.16. The lowest gear ratio (for climbing) was 30/25=1.2.

My new bike is a 'compact' with 50/34 on the front and 28/11 on the back. So the highest gear ratio is 50/11=4.5 and the lowest is 34/28=1.2.

So the compact is better for speed (4.5 v 4.16), and no worse for climbing (1.2 v 1.2). The triple has 27 gears and the compact has 20. So with the compact you don't have the same ability to change gears by just a 'smidge'. But then you only have to worry about two cogs on the front, and you are not changing as often.

All 'compacts' (to the best of my knowledge) have 50/34 on the front. You can pick whatever cassette you need for the rear, but if you are struggling on the hills (like me) then specify a 28/11 on the back (and the bigger the number, i.e. 28, means the lower gear ratio you have).

PM me if you like, I put all the gear ratios into an Excel spreadsheet to work it out before I made the choice. I'm an average cyclist and I would never elect for a triple again, Compact all the way.

Lumen

youtheman wrote: »

My first bike had a triple, and when I was going to purchase my second (carbon) bike I had a good look at the issue of gearing. It's not the number of gears that is important, it's the gearing ratios that is important. When you are in a given gear the ratio is (number of teeth on front cog) divided by (number of teeth on rear cassette).

For example my old bike was a triple with 50/39/30 teeth on the front cog with a rear casette with 25/12 teeth on the back. So the biggest gearing ratio (for speed) was 50/12=4.16. The lowest gear ratio (for climbing) was 30/25=1.2.

My new bike is a 'compact' with 50/34 on the front and 28/11 on the back. So the highest gear ratio is 50/11=4.5 and the lowest is 34/28=1.2.

So the compact is better for speed (4.5 v 4.16), and no worse for climbing (1.2 v 1.2). The triple has 27 gears and the compact has 20. So with the compact you don't have the same ability to change gears by just a 'smidge'. But then you only have to worry about two cogs on the front, and you are not changing as often.

All 'compacts' (to the best of my knowledge) have 50/34 on the front. You can pick whatever cassette you need for the rear, but if you are struggling on the hills (like me) then specify a 28/11 on the back (and the bigger the number, i.e. 28, means the lower gear ratio you have).

PM me if you like, I put all the gear ratios into an Excel spreadsheet to work it out before I made the choice. I'm an average cyclist and I would never elect for a triple again, Compact all the way.

...but as you've indicated yourself, you've gone from a nicely spaced 12-25 cassette on the triple to a gappy monster of an 11-28 on the compact, and the jump at the front is now a huge 47% rather than the nice 30% you had with the triple.

How is that better?

loinnsigh

This is great, thanks all.

I've worked out the gear ratios for the bikes I'm looking at:
The lowest ratio on my favourite compact is 34/30=1.13 (gear ratio using online calculator = 2.2).
The lowest ratio on my favourite triple is 30/25=1.2 (using online calc = 2.4).
Highest ratios are pretty similar on both.
So the compact would actually be better for climbing.

Choosing a bike just got a lot easier - compact all the way

on_the_nickel

Be careful, you are now liable to impregnate women at a single glance.

youtheman

Lumen wrote: »

...but as you've indicated yourself, you've gone from a nicely spaced 12-25 cassette on the triple to a gappy monster of an 11-28 on the compact, and the jump at the front is now a huge 47% rather than the nice 30% you had with the triple.

How is that better?

It's hard to explain. With 27 gears on the triple I don't have the same ability to 'fine tune' as I do with the 20 gears on the 'compact'. This is offset by the fact that if you want to go down the gears in a triple, with the mimimum change in gear ratio, then you will end up going from top cog to middle cog, then back up to top cog for a gear or two, then back to the middle, then eventually down to the bottom, then up to the middle again and so on (if you put it into Excel you'll see what I mean). So when I want to change gear in the 'compact' I have to elect for a slightly bigger change in gear ratio (not necessarily a bad thing), but there is less frigging about with the levers as I only have two settings on the front cog (and this is what takes more effort to change).

As I said before, I'm an average cyclist and there is no way I would ever go for a triple again.

loinnsigh

on_the_nickel wrote: »

Be careful, you are now liable to impregnate women at a single glance.

Duly noted - was unaware till now of the serious threat that a triple ring poses to a man's virility. Phew.

Lumen

loinnsigh wrote: »

I've worked out the gear ratios for the bikes I'm looking at:
The lowest ratio on my favourite compact is 34/30=1.13 (gear ratio using online calculator = 2.2).
The lowest ratio on my favourite triple is 30/25=1.2 (using online calc = 2.4).
Highest ratios are pretty similar on both.
So the compact would actually be better for climbing.

Almost nobody uses 30t sprockets on the rear of a road bike. You need a mid- or long-cage rear derailleur for that, since most of the normal short cage derailleurs only go to 28t. So the shifting will be worse and you're ignoring the gappiness issue.

At your weight a compact with a 11- or 12-25 cassette should be fine.

dermur

loinnsigh wrote: »

The lowest ratio on my favourite compact is 34/30=1.13 (gear ratio using online calculator = 2.2).

I'm just impressed that you've found a cassette with a 30-tooth sprocket! What's the range...30-11?

My only advice would be to consider the size of the derailleur cage with a cassette like that 'cos it could limit your upgrade options.

Edit - Lumen made a good point while I was typing away...unless you're going to be cycling up walls or plan on adding another 30Kg in body weight anytime soon, you probably won't ever use a 30 ring. Don't try to get a "one cassette fits all" becuase you'll sacrifice too much in terms of gear increments and reliability with the longer cage.

Lumen

youtheman wrote: »

It's hard to explain. With 27 gears on the triple I don't have the same ability to 'fine tune' as I do with the 20 gears on the 'compact'. This is offset by the fact that if you want to go down the gears in a triple, with the mimimum change in gear ratio, then you will end up going from top cog to middle cog, then back up to top cog for a gear or two, then back to the middle, then eventually down to the bottom, then up to the middle again and so on (if you put it into Excel you'll see what I mean). So when I want to change gear in the 'compact' I have to elect for a slightly bigger change in gear ratio (not necessarily a bad thing), but there is less frigging about with the levers as I only have two settings on the front cog (and this is what takes more effort to change).

A triple is just a standard double with a granny ring. So you're basically saying that a there is "more frigging around with levers" on a standard double than on a compact. I can't dismiss your anecdotal experience, but almost everybody would disagree with this statement.

A triple should be ridden like a standard double, with the granny ring used only for really steep bits.

loinnsigh

dermur wrote: »

I'm just impressed that you've found a cassette with a 30-tooth sprocket! What's the range...30-11?

My only advice would be to consider the size of the derailleur cage with a cassette like that 'cos it could limit your upgrade options.

Edit - Lumen made a good point while I was typing away...unless you're going to be cycling up walls or plan on adding another 30Kg in body weight anytime soon, you probably won't ever use a 30 ring. Don't try to get a "one cassette fits all" becuase you'll sacrifice too much in terms of gear increments and reliability with the longer cage.

It's a Shimano Tiagra 12-30T - new for 2012 apparently.
The bike I'm looking at is a Felt Z85, and the spec states that the rear derailleur is a Shimano 105 SS short cage.

ROK ON

loinnsigh wrote: »

It's a Shimano Tiagra 12-30T - new for 2012 apparently.
The bike I'm looking at is a Felt Z85, and the spec states that the rear derailleur is a Shimano 105 SS short cage.

At 65kg you are very lucky. You will be fine on a compact, but to be honest unless you plan on spending life in the Alps or Pyrenees that you probably should use a standard double and put a 12/27 on the rear.

At your weight if you cannot get up the climbs in Wicklow on a standard then you are simply not as fit as you believe you are. But that will come with time on the bike.

I weigh 50% more than you and I use a compact with 12/27 when on Wicklow type climbs. I get up slowly, but other wise fine.
Think about the advantages that you have climbing at your weight. That should guide you.

youtheman

Lumen wrote: »

So you're basically saying that a there is "more frigging around with levers" on a standard double than on a compact. I can't dismiss your anecdotal experience, but almost everybody would disagree with this statement.

No. This is not what I'm saying. All my comments relate to Triple v Compact. And I'd argue about the use of the word 'anecdotal' also (but that is for another day).

dermur

loinnsigh wrote: »

The bike I'm looking at is a Felt Z85, and the spec states that the rear derailleur is a Shimano 105 SS short cage

Nice bike! I had a Felt Z80 myself and it still ranks as one of my favourites.

I can't understand why they're offering a short cage with a 30 tooth sprocket on the cassette.

Typical cage size capacity would be as shown below...

Cage Size (Capacity)
Short (30T)
Medium (33T,37T)
Long (43T,45T)

You can use the formula: (big ring - small ring) + (big cog - small cog) to see which gear combinations won't work with a particular cage size.

For example, a medium-size cage might give you problems with the gear combos in red below which exceed the recommended capacity. The idea being that the longer the cage the more chain slack can be taken up.

Gear ratios are handy for quick calculations but if you really want to answer a question like "what difference will a 30T granny ring make over a 39T ring" you should be looking at gear inches (how far will one revolution of the pedals take me?)

smacl

dermur wrote: »

Gear ratios are handy for quick calculations but if you really want to answer a question like "what difference will a 30T granny ring make over a 39T ring" you should be looking at gear inches (how far will one revolution of the pedals take me?)

Very true. Alternatively, take the bike for a trial run up a rampy hill like Kilmashogue, just to make sure you can make the wheels revolve at all

cdaly_

loinnsigh wrote: »

I've worked out the gear ratios for the bikes I'm looking at:
The lowest ratio on my favourite compact is 34/30=1.13 (gear ratio using online calculator = 2.2).
The lowest ratio on my favourite triple is 30/25=1.2 (using online calc = 2.4).
Highest ratios are pretty similar on both.
So the compact would actually be better for climbing.

Choosing a bike just got a lot easier - compact all the way

Just to throw a spanner in the works, you can very easily change the cassette on the triple to give you a lower climbing gear and the bike shop should do that FOC at purchase time...

dermur wrote: »

Gear ratios are handy for quick calculations but if you really want to answer a question like "what difference will a 30T granny ring make over a 39T ring" you should be looking at gear inches (how far will one revolution of the pedals take me?)

What you're talking about there is 'development'. Gear inches is a virtual number giving the diameter of a directly driven wheel which corresponds to your gear ratio.

C3PO

Recently changed from a Compact to Standard on the race bike and I'm much happier with the ratios on the front with the Standard. I always found that, with the Compact set-up, a change up or down at the front always had to be accompanied by a change at the back to get the gear you wanted!
So, apart from the uncool factor, I think I would go with the Triple!

smacl

Uncool is also a relative term. Triples may not be cool, but they're way cooler than pushing a bike up a hill.

Hungrycol

Buying a bike with a compact chainset and don't really want it, would prefer a standard double but no choice in the matter. Can you change the chainrings to make it a standard or do you have to buy a new chainset? It's Shimano 5700. Appreciate I may need a short cage RD also.

Lumen

Hungrycol wrote: »

Buying a bike with a compact chainset and don't really want it, would prefer a standard double but no choice in the matter. Can you change the chainrings to make it a standard or do you have to buy a new chainset? It's Shimano 5700. Appreciate I may need a short cage RD also.

I'd leave the 50t and just change the 34t ring for a 38t.

Don't know much about Shimano but this is the sort of thing...

http://www.artscyclery.com/descpage-SRCRRF3811B.html