Triple / double trade-off

[Willo]

Conscious of igniting a double/compact vs triple debate, but in considering getting a new bike I just want to try and quantify the real difference if I move from my current triple (52/42/30) to a double (50/34).

In short, how much will I materially lose, particularly at the lower extreme where, while I seldom use the small front ring nowadays, I sometimes resort to the the lowest gear to keep me spinning (well, just moving!) towards the end of longer rides when really suffering going up a hill?

 

[Fiona N]

Well if your wheels are 27inch (700) and the rear sprockets are the same - say 27 as largest, you'll end up with 4 gear inches 'missing' from the low end with a compact. While this doesn't sound much 34 inch v. 30 inch, it's more than 10% difference so if you're at the limit with 30inch on a hill, it's likely the 34inch will be too high for you.

However, if you combine the compact with a bigger block (say you had 23 tooth as largest with the triple and went to 27 with the compact) you could get the same gear or a bit lower (e.g. 34 with 27 on the compact v. 35 with 23 on the triple).

Most people find the big/little switching is the problem with the compact rather than the lack of low gears. personally it doesn't bother me and a like my Campag compact on the Hewitt but others will be along to tell you just how dreadful they are

 

[SquareDaff]

Have recently made the same switch and I can't say I notice the difference. I still rarely use "top" and "bottom". I felt a lot of the gears on a triple were just too similar - having a compact for mean literally means small ring on front for hills / spinning into winds etc... big ring on front for downhills / flats. The mech at the back then controls how much spinning I have to do to get to a speed - or how easy I want to make it to accelerate.

 

[Willo]

Thanks for the replies. I'm pretty dumb when it comes to calculating gearing and it's been a long day but, looking more closely at the specifications, the 2012 Felt Z85 comes with a 12-30T casssette versus a 12-25 on my triple. Therefore, l assume that will provide as low a gear as my triple (lower?) but just without as many steps between highest to lowest gears. Am I missing something?

 

[hondated]

Willo I have just carried out this experiment on my bike by removing my triple and fitting a 50/34 mainly because I see far more people riding compacts than I do triples so I thought give it a go.Anyway I cycled one of my usual routes and yes I climbed the hills that I normally do but as someone has already stated it was far more like hard work than when I am on a triple.

So even though I prefer the look of a compact and many people ride them for me it was a no brainer why suffer unnecessarilly when you do not have to so now the triple is back on.

Perhaps one day when I lose some weight I may give it another go but until then its a triple for me.

 

[YahudaMoon]

I have a compact 48 x 34. If you love climbimg hills all day as I do get a triple

 

[totallyfixed]

Well if your wheels are 27inch (700) and the rear sprockets are the same - say 27 as largest, you'll end up with 4 gear inches 'missing' from the low end with a compact. While this doesn't sound much 34 inch v. 30 inch, it's more than 10% difference so if you're at the limit with 30inch on a hill, it's likely the 34inch will be too high for you.

However, if you combine the compact with a bigger block (say you had 23 tooth as largest with the triple and went to 27 with the compact) you could get the same gear or a bit lower (e.g. 34 with 27 on the compact v. 35 with 23 on the triple).

Most people find the big/little switching is the problem with the compact rather than the lack of low gears. personally it doesn't bother me and a like my Campag compact on the Hewitt but others will be along to tell you just how dreadful they are

Had to say it......they are dreadful. They seem to have arrived about the same time as sportives and sportive bikes - whatever they are. When I'm not riding fixed I ride a triple 12x25 or 12x23, in Cornwall on holiday did a 33% and boy was my granny gear useful then. The chain line on compacts tends to be awful because most people [at least in my club] that have them stay in the big ring for all but steeper climbs and this means a lot more wear on chain, cassette and chain ring. Ok shoot me down

 

[Willo]

Thanks again. Notwithstanding the fact that a compact obviously has less gears overall and noting the wear and tear cons flagged, regarding low gearing for the hills surely the example of the Felt with a 12-30 cassette offers a gear at least as low as my current triple, if not lower?

 

[aberal]

Thanks again. Notwithstanding the fact that a compact obviously has less gears overall and noting the wear and tear cons flagged, regarding low gearing for the hills surely the example of the Felt with a 12-30 cassette offers a gear at least as low as my current triple, if not lower?

It does. What you will find with this argument (compact vs. triple) is that a lot of people really don't understand gearing.

I have a triple with a 30 front and 25 rear. A compact with a 34 front and 28 rear gives a virtually identical low gear. So is there any point in having a triple if you can get as low a gear on a compact? Well, yes. If you regulary spin out your highest gear at 40mph+ then the larger chainring on a triple gives you an advantage there. And the ratios are closer together on a triple which can help with your cadence, although there is overlapping of gear ratios. OTOH the chain line is better with a compact (therefore less wear and tear, contrary to that argument ) and the mechanism in the shifter is simpler, the rear deraileur is a shorter cage and the overall weight is less. So all in all its all about pros and cons, but to be honest, although I ride with a triple I don't believe that its really necessary and on rolling, switchback terrain a total pain in the derriere.

 

[2Loose]

It does. What you will find with this argument (compact vs. triple) is that a lot of people really don't understand gearing.

I have a triple with a 30 front and 25 rear. A compact with a 34 front and 28 rear gives a virtually identical low gear. So is there any point in having a triple if you can get as low a gear on a compact? Well, yes. If you regulary spin out your highest gear at 40mph+ then the larger chainring on a triple gives you an advantage there. And the ratios are closer together on a triple which can help with your cadence, although there is overlapping of gear ratios. OTOH the chain line is better with a compact (therefore less wear and tear, contrary to that argument ) and the mechanism in the shifter is simpler, the rear deraileur is a shorter cage and the overall weight is less. So all in all its all about pros and cons, but to be honest, although I ride with a triple I don't believe that its really necessary and on rolling, switchback terrain a total pain in the derriere.

+1 Well Said

 

[Willo]

Really appreciate the replies and, aberal, that makes perfect sense and confirms my logic. I like my Allez triple and it servces me well. However, I only really need a fraction of the gears and, if I have the low gear for the occassions when my skinny legs can no longer push me up the hills, am sure a compact would serve me just fine.

Now just have the more complex decision of whether I can justify a new bike to use as a 'Sunday Best' (through C2W so could argue it's too good an offer to refuse versus I have a road bike already!)

 

[fossyant]

Had to say it......they are dreadful. They seem to have arrived about the same time as sportives and sportive bikes - whatever they are. When I'm not riding fixed I ride a triple 12x25 or 12x23, in Cornwall on holiday did a 33% and boy was my granny gear useful then. The chain line on compacts tends to be awful because most people [at least in my club] that have them stay in the big ring for all but steeper climbs and this means a lot more wear on chain, cassette and chain ring. Ok shoot me down

Hmm this has been my thought. I've always used 52/53 and 42.39 - All road bikes are on a 53/39 now. The road bikes have either a 21 or 24 on the back. This is where my problem is. I'm looking at possibly getting a new bike, with a compact and a 12-25 or even 27 rear as my left shoulder isn't too good anymore, and I can't grind up the very steep stuff without pain.

Anyone want to comment about compacts in day to day use. Some folk say you are always changing between chain rings, others say they are great.

 

[tigger]

Anyone want to comment about compacts in day to day use. Some folk say you are always changing between chain rings, others say they are great.

I've got a triple 53/39/30 13-23 and a compact 50/34 11-28. The overall range of gears is pretty similar, although the compact actually has the highest and lowest gear of the two. I live in the peak district, so its hilly and rolling. I don't find I change between the chain rings any more on the compact, possibly less in fact as I have a bigger spread of gears across the cassette. The change from small ring to big isn't quite as smooth as a triple but nothing to worry about, change from big to small very quick and smooth.

For me its compact all the way. The real question for me surrounds cassette choice on a compact and cadence. Mine is 11,12,13,14,15,17,19,22,25,28. Its a little gappy as you can see from 19 upwards, so from a cadence point of view its not always a perfect progression, sometimes a little spinny or grindy than you'd like in the ideal world. Having said that, I'm 90kg, average ability and theres lots of hills so the overall range is good for me. If your lighter and stronger you might not need such low gears, infact I rarely use the 28 sprocket anyway (but nice to have as a bail out / mental thing!) and the 11 is a pretty big gear that isn't essential either. A 12-25 would possibly be the best spread and more even progression. 12,13,14,15,16,17,19,21,23,25 would be very good if you don't need the really big dish

 

[Sleeper]

I've just gone to a 53/39 double from a 44/32/22(!!) triple. With 12-25 out back a spread from high 1:4.5 to low 1:1.6 will see me over everything the tyres can handle! If you're in the Market for a std double crankset, check out CRC's FSA team issue package- it's about £140 off right now :-)))

 

[andrew_s]

So is there any point in having a triple if you can get as low a gear on a compact?

Another point is that if the 34x30 bottom gear on the compact isn't as low as you want (eg for an alpine holiday), it's a lot more expensive to do anything about it, and you can't do as much.


With compact, the lowest you can go is 34x34, which requires that you swap your existing rear mech for an MTB rear mech (That's assuming Shimano/SRAM - with Campag you are already at the limit on 34x30).
With a triple, as well as swapping the cassette down to 30T, you can also swap the 30T chainring down as low as 24T. Also, a 28T, 26T or 24T chainring is cheaper than a new cassette.