Triple to Compact

AlanW · Post by **AlanW** » 18 Jul 2012 08:22

Let me start by saying that for audax events I love my triple chain set (sometimes a 28T but mainly 30/39/52) as it gives me the range I require both at the top and bottom. Furthermore I can maintain a smooth cadence thanks to a fairly close ratio on the 10sp cassette, either 12/23 or 12/25. So my normal combo will give me 31.5” at the bottom and 113.9” at the top.

BUT......times have moved and for what ever reason I keep eying up the compact chain sets, and I’ll be honest, I do much prefer the look and the less clutter of a compact over a triple.

Now of course I appreciate that compared to the triple you may lose a little at the top and bottom ends, but I also like the fact that you don’t have the duplication of ratios and only two chain rings to work with. These are a couple of interesting articles -

HERE

HERE

I have spent far to long on the Sheldon Brown gear calculator analysing the many different gear options and printing them of to compare. But the bottom line is that I’m looking at a 34/50 with a 12/27 10 sp cassette, this will give me 33.1” bottom and 109.5” top.

It is particularly interesting to note the percentage jumps between a 30/39/52 & 12/25 and a 34/50 & 12/27. So on paper it makes sense, but then again lot of things on paper make sense but are rubbish in the real world!

Like most things in life its all down to personal preference and what suits one will not suit another, but has anyone changed from a triple to a compact, if so what was your verdict?

However, please tell me to stop being stupid, if what I have works, then stop messing!

Andy Terry · Post by **Andy Terry** » 18 Jul 2012 10:18

I am a triple user, and what I find is that I spend 90% of my time in the middle ring, using the middle 6 cogs of the rear sprocket i.e. in the range 49 to 73 in. If I had a compact, I would be switching back and forth between small and large rings to achieve the same effect.

AlanW · Post by **AlanW** » 18 Jul 2012 13:33

My thoughts entirely Andy, but have you tried one?

Interesting read HERE

Andy Terry · Post by **Andy Terry** » 18 Jul 2012 13:47

"and it’s plainly obvious that the double requires less front shifting AND less rear shifting to find the right gear ratio."

plainly obvious? I don't think so

"Frankly, from a physiological standpoint, you’re better off pushing those larger gears uphill"

dear oh dear

I'll stay with my triple, thank you.

Kermit · Post by **Kermit** » 18 Jul 2012 13:57

I have been using both for about 3 years and just to confuse matters, love them both!

Triples on my Audax and touring bikes - I just have to have those low, low gears. And compact on my lightest racing bike for when I feel like flying. IMHO it's all about riding styles. If I ride my compact bike in a more casual style I'm constantly changing between rings, but as I'm usually riding it quite hard I spend 90% of the time in the big ring.

Grogz · Post by **Grogz** » 18 Jul 2012 19:28

AlanW wrote:... will give me 33.1” bottom...

What will I shelter behind?

I use a triple on my winter bike and agree with Steve that it's very comfortable in the middle ring.

On my best bike, it's a 50/36 compact. Like Paul, I spend most of my time in the big ring, particularly now I've fitted a 11-28 cassette. However, I've had a few issues with the front mech recently, meaning I couldn't select the middle few rear cogs from the 36 ring. That showed how important the cross-over is in the middle of the cassette!

Now I'm wondering whether to get a 53/39?

AlanW · Post by **AlanW** » 18 Jul 2012 20:18

Grogz wrote:
AlanW wrote:... will give me 33.1” bottom...
What will I shelter behind?

Cheeky.

Grogz wrote:I use a triple on my winter bike and agree with Steve that it's very comfortable in the middle ring.

On my best bike, it's a 50/36 compact. Like Paul, I spend most of my time in the big ring, particularly now I've fitted a 11-28 cassette. However, I've had a few issues with the front mech recently, meaning I couldn't select the middle few rear cogs from the 36 ring. That showed how important the cross-over is in the middle of the cassette!

Now I'm wondering whether to get a 53/39?

I have 39/52 and 12/23 on my everyday bike and it is very rare that I ever use the 52 outer. Most of the time I spend on the 39/14 (73.2") and its pretty rare on most of my rides that I have to use the 39/23 (44.6")

On the flip side, on my best bike I have the exact same gearing but hardly use the inner ring.

So in theory and looking at the figures on a piece of paper, a compact is not for me and probably not for a lot of other people as well.

So why is it that compacts are so popular, or is it just a case of no one wants to be seen with a triple as its perceived as not being cool and trendy?

Post by **CakeStop** » 18 Jul 2012 20:22

Shirley, as others have suggested, the wise choice depends on what you'll use the bike for and where rather than any calculation or aesthetic consideration.

AlanW · Post by **AlanW** » 18 Jul 2012 21:01

CakeStop wrote:Shirley, as others have suggested, the wise choice depends on what you'll use the bike for and where rather than any calculation or aesthetic consideration.

Yes, but you have to do the calculations first in order to understand the comparisons.

In truth I really think that I don't "need" one, but as a compulsive fiddler I do like to explore other options in just about everything.

After all, it could be the best thing that I ever bought, who knows?

I recall Greg doing some pretty mean leg spinning on the last Beacon Audax when he was going from the outer to inner.

In saying all that, from an engineering point of view it all seems to stack in favour of a compact, but I am very mindful of the need to double shift in order to get your appropriate gear ratio.

So its also helpful to get a feel from other peoples experiences, good or bad

Andy Terry · Post by **Andy Terry** » 18 Jul 2012 22:33

http://bikehugger.com/post/view/the-ris ... act-crank/

and in particular

"Component manufacturers would rather offer compact double cranksets instead of triples. Even if they could produce a triple version of a standard double with minimal changes to tooling, the complexity of producing triple shifters and derailleurs to match far outweigh the cost developing the molds or dies for the compact crank. And for companies offering complete bikes, they know that they can often get away with offering road bikes only with compact cranks, particularly in the entry- to mid-level segments. Reduced variation means easier stocking, which leads to better profitability."

GrahamGamblin · Post by **GrahamGamblin** » 19 Jul 2012 14:47

I had a triple in the past and never ever used the inner ring. Now I have 50-34 compact and it suits me fine - with 12-25 I have the right spread of gears, low enough to get up any hills round here, high enough for a bit of speed. Changing between rings is a bit of a big jump though and usually needs a shift up/down at the back to make it comfortable. I think compacts have become popular because they suit middling cyclists like me who don't need very low or very high gearing.

AlanW · Post by **AlanW** » 27 Aug 2012 13:26

Well in the end curiosity got the better of me and I bought a 50/34 compact chain set.

I fitted it last night together with a 12/27 10sp cassette and I have just tried it out this morning on a 55 mile spin out. I have to say I have rather taken to it, although that said I'm not to sure what I was expecting?

But it all works well, and I love the fact that for 90% of the time the chain line is near enough perfect. Okay, so you may have to double shift from time to time, but you have to do that anyway what ever chain set you have.

Its early days I know, but after my first ride out this morning, I can now see the attraction with the compact over a triple.

I have lost out a little on my bottom gear compared to the triple, 33.1" compared 31.5" but what's 1.6" between friends.

To be fair, I could fit a 12/28 which would give me 31.9", but the ratios in the middle are more important to me to be honest.

laurence_cooley · Post by **laurence_cooley** » 27 Aug 2012 13:37

I see you took a couple of Strava KOMs - can't be bad.

AlanW · Post by **AlanW** » 27 Aug 2012 13:59

laurence_cooley wrote:I see you took a couple of Strava KOMs - can't be bad.

Both KOMs back to back within about 1/2 mile of each other and after a 50 mile ride to. I was going for a third. but as I turned the corner and started to wind it up, a flipping tractor appeared in the middle of the road cutting the hedge......

Dave Cox · Post by **Dave Cox** » 27 Aug 2012 15:07

I mostly switched to triples after doing my knee in on Edge Hill on a Beacon Audax years ago: But then only standard sets were available: Tried a compact nine speed for a while and didnt like it at all always on the edge of the big front gap:

Andy Terry · Post by **Andy Terry** » 27 Aug 2012 17:16

Don't bin that triple, you might be glad of it when you get a bit older

I had offers to swap compacts for my triple on the Bwlch y Groes yesterday.

Tim · Post by **Tim** » 27 Aug 2012 19:55

Is it just me or is there anyone else who just doesnt get the gear ratios!?!

Ive read articles on it in bike magazines, Alistair from BCC tried to explain it to me a few years back (he said go for a compact), have read this thread. And I still dont get the numbers!

I had the dilema when getting my first road bike 3 years ago, triple or compact? and after much thought and posting the question on bike radar which came back with around 50/50 answers in favour of each, I went for a compact.

I got around the etape which finished at the top of the tourmallet a year later (slowly in 11 hours for 113miles) and have never had to get off to walk on any climb (although came very very close on this years little mountain time trial). So I feel I made the right choice. But have never ridden a triple or standard double.

But can anyone explain in complete idiots language! What the number mean when describing the gear ratio, i know its the number of teeth I think?!, but dont get whether a higher number means easier to climb/faster to sprint or whatever??????????

And what set up do people have when racing?

Thanks!

Tim

Andy Terry · Post by **Andy Terry** » 27 Aug 2012 21:32

http://www.sheldonbrown.com/gloss_g.html#gearinch

Ed Moss · Post by **Ed Moss** » 27 Aug 2012 21:38

Can only really help with racing

Road racing I use a 53/39 with 11-21 rear or 11-23 if its a bit hilly
Time trialling 55/39 with 11-21 rear, or 11-23 for the LMTT.

Don't know much about the numbers, best way to find what suits you is to go out and ride.

AlanW · Post by **AlanW** » 27 Aug 2012 21:44

Tim wrote:Is it just me or is there anyone else who just doesnt get the gear ratios!?!

Ive read articles on it in bike magazines, Alistair from BCC tried to explain it to me a few years back (he said go for a compact), have read this thread. And I still dont get the numbers!

I had the dilema when getting my first road bike 3 years ago, triple or compact? and after much thought and posting the question on bike radar which came back with around 50/50 answers in favour of each, I went for a compact.

I got around the etape which finished at the top of the tourmallet a year later (slowly in 11 hours for 113miles) and have never had to get off to walk on any climb (although came very very close on this years little mountain time trial). So I feel I made the right choice. But have never ridden a triple or standard double.

But can anyone explain in complete idiots language! What the number mean when describing the gear ratio, i know its the number of teeth I think?!, but dont get whether a higher number means easier to climb/faster to sprint or whatever??????????

And what set up do people have when racing?

Thanks!

Tim

See if this helps Tim

Origin of the term

When the high wheeler was the "ordinary" bicycle form, the comparative diameter in inches of the driven wheel was an indication of relative speed and effort. A 60 inch wheel propelled a bicycle faster than a 50 inch wheel when both were cranked at the same cadence. The technology of the high wheeler imposed a natural limit -- a 60 inch wheel was about the maximum size that could be straddled by ordinary sized legs. When "safeties" replaced "ordinaries," chains and sprockets allowed small wheels to be turned faster than the pedal cranks. As result, a 28 inch wheel could be made to move a bicycle at the same speed as a 60 inch wheel. Such a bicycle was then said to be geared at 60 gear inches and pedalled similar to an ordinary with a 60 inch wheel. Thus on a bicycle geared at 72 gear inches one revolution of the pedals advances the bicycle the distance that a 72 inch wheel would in one revolution.

So in simple terms the lower the number in inches the easier it is to climb. But it all depends on the person, as some people like to spin while some people like to slog, only you know what suits you best when climbing.

On the top end of the scale, the higher the number the faster you go, well in theory that is. 53/11 for example gives you a whopping eye watering 130" gear, and unless you are a top pro is a complete and utter waste of time.

Most club riders will only need around a 100" gear which is 52/14 or a 50/13(14) and gear ratios in the middle are of much more benefit. Even then, you still need to be a strong rider to keep a good pace pushing a 100" gear.

AlanW · Post by **AlanW** » 27 Aug 2012 21:54

THIS explains it all very well, plus a gear calculator.

But THIS gear calculator is nice and easy.

rdleaper · Post by **rdleaper** » 28 Aug 2012 09:28

When I'm pedalling I only understand speeds (mph), which seems to make for a tricky conversion:
Let's say I'm in a low gear for a hill such as 32/24, and am pedalling at 80 rpm. My tyres are 29" diameter which is about 736mm or 0.736m.
With each pedal stroke I am travelling 0.736 x pi x 32/24 = 3.08m. At 80 rpm I am doing 3.08 x 80/60 = 4.11 metres per second. Rough conversion to mph = 4.11 x 9.25 mph.
Does this sound about right? If so from now on I'll stay well away from talk of gear ratios. I'm comfortable with maths but this is making my head hurt!

AlanW · Post by **AlanW** » 28 Aug 2012 09:34

Andy Terry wrote:Don't bin that triple, you might be glad of it when you get a bit older

Don worry, I have no plans to bin my triple. The compact is for one of my other bikes just to give it a bit more flexibilty and the compact route was the cheapest way to do it.

Tim · Post by **Tim** » 28 Aug 2012 19:46

Brain is in pain but thanks, think I understand a little more.

Think I will just stick to the ride and see how I get on tactic for the moment though.

Andy Terry · Post by **Andy Terry** » 28 Aug 2012 21:15

rdleaper wrote:When I'm pedalling I only understand speeds (mph), which seems to make for a tricky conversion:
Let's say I'm in a low gear for a hill such as 32/24, and am pedalling at 80 rpm. My tyres are 29" diameter which is about 736mm or 0.736m.
With each pedal stroke I am travelling 0.736 x pi x 32/24 = 3.08m. At 80 rpm I am doing 3.08 x 80/60 = 4.11 metres per second. Rough conversion to mph = 4.11 x 9.25 mph.
Does this sound about right? If so from now on I'll stay well away from talk of gear ratios. I'm comfortable with maths but this is making my head hurt!

Dead right - not sure about your 29" diameter though - 700c wheel with 23mm tyre is 26.3" (0.668m)

With 32x24 gear, the 'development' in metres is 2.8

At 80 rpm, 13.44 km/h (8.35 mph)

rdleaper · Post by **rdleaper** » 28 Aug 2012 22:20

Andy Terry wrote:
rdleaper wrote:When I'm pedalling I only understand speeds (mph), which seems to make for a tricky conversion:
Let's say I'm in a low gear for a hill such as 32/24, and am pedalling at 80 rpm. My tyres are 29" diameter which is about 736mm or 0.736m.
With each pedal stroke I am travelling 0.736 x pi x 32/24 = 3.08m. At 80 rpm I am doing 3.08 x 80/60 = 4.11 metres per second. Rough conversion to mph = 4.11 x 9.25 mph.
Does this sound about right? If so from now on I'll stay well away from talk of gear ratios. I'm comfortable with maths but this is making my head hurt!
Dead right - not sure about your 29" diameter though - 700c wheel with 23mm tyre is 26.3" (0.668m)

With 32x24 gear, the 'development' in metres is 2.8

At 80 rpm, 13.44 km/h (8.35 mph)

OK cheers - that was a half-guess! The slightly lower speed makes a little more sense anyway.

WARNING - GEEK ALERT

I think I'll use a constant of 0.668 x pi x 9/4 = 4.722 and work out speeds from there by factoring in rpm and gear ratio - if I feel that way inclined

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