Fair criticisms of compact chainsets?

[TheJDog]

I often wonder about that ... 50/11 is a big ratio (4.55:1). roughly equivalent to a 55/12! I rarely use even the 53/13 on my Cannondale so I am downgearing that to a 48/13 in search of more useful flat and uphill gears. (I can often freewheel downhill at 40+ mph round here.)

12-26 and a 50/34 was enough for me up _and_ down Leith Hill etc., top speed over 70 kph, bottom speed probably around 3mph on White Down.

 

[Venod]

This kind?

Are you stalking that woman ?

 

[cyberknight]

There are compacts and compacts. The two bikes I had previously were geared 50/36 and 48/34, the lower gears being on the winter iron. For general riding 48*12 is easily high enough for most people unless you like playing "How fast can I get my computer to record" on the descents. For the moment I have 50/34 on my bike but I plan to swap the inner to a 36, the 16t jump is just that bit too much.

I have done this on my compacts for exactly the same reason .
The commuter now has 50/36 with 12-25 and the weekender has 50/36 with an 11-28 , for some reason i spin faster on the weekender as its not got rack and panniers maybe so i am am going faster in the same gear ratios .I generally start on the flat in 36 x 19 and drop into the big ring as soon as i am going then up to 50x 17/15 on the flat .

 

[ColinJ]

Are stalking that woman ?

She did keep turning round and asking me not to take pictures of her ... I told her that I was photographing the hill but she kept getting in the way!

(Nothing sinister - we are old friends and were out on a walk.)

 

[vickster]

Do you need that 11 tooth small cog?

Possibly - I am old, heavy and with dodgy knees...barely ever used it though...what came with the bikes so...

 

[MrWill]

Finally the future is bright. Found a 5700 30/39/50 105 triple for £70.

Just need the other bits now.

 

[srw]

I won't repeat my thoughts on compacts - you can find them here if you're so inclined. And I see that I agreed with the OP's analysis back in 2011.

Do you need that 11 tooth small cog?

It's one of the most useful I/we possess - it means the middle ring can be used for fast as well as moderate, and the big ring can be used for very fast rather than just fast. An 11-tooth cog is 9% faster than a 12-tooth cog for the same cadence. Which is rather useful.

 

[Deleted member 1258]

I couldn't get on with 50/34, the 50 is to big the 34 is to small, very quickly after I brought my Verenti the 34 got swapped for a 42, I mostly ride on the 42, the 50 only gets used downhill with a following wind.

 

[GrasB]

I keep hitting the spot at 18/19mph were 4 cassette and 1 chain ring shifts are needed on the compact, which costs me speed. Whereas is 2 cassette shifts and on chainring on the triple seems better

I'd get a standard double but need a fairly low gear for some 20% but short climbs and the days after leg day in the gym. The 34-25 ratio is adequate though.

I like the idea of the triple being simple to use.

High 25mph+
mid 0-25mph
low, 0-15mph

For road bike usage I could level a similar criticism at a triple.

Take a 30/39/52 chain set and 11-26 cassette the bottom chainring is too low topping out at about 24mph but the middle chainring however is too high as it doesn't allow for much bellow 12mph at a good cadence. The result is I'm constantly swapping chainrings between the middle & bottom on rolling terrain. Sure the top chainring is good for longer mostly downhill sections but then again this makes it no different to a compact top chainring.

Compare that to a 34/50 compact. The bottom chainring takes me from around 8.5 to 29mph, from 16mph up it's on the lovely tight ratio section, & the top chainring starts at about 1mph higher than the middle on the double with the tight ratios being from 23mph up. Net result is that I do a lot less shifting on a compact than a triple.

Also worth mentioning that on a triple once beyond a certain chain line deviation you're looking at massive drive train efficiency reductions. These reductions simply aren't present on road double chainring setups due to the chain line deviation not being wide enough. Another bonus for me is that I can machine my own double chainrings without issue with doubles but on triples suitable for road bikes you really need to machine proper ramps in or shifting becomes very haphazard.

It's a very personal thing. My riding style & strength means a triple doesn't make much sense to me & the larger gaps in the sprockets at the bottom end of the cassette aren't a problem in my mind.

 

[T4tomo]

It's a very personal thing. My riding style & strength means a triple doesn't make much sense to me & the larger gaps in the sprockets at the bottom end of the cassette aren't a problem in my mind.

Or location: nr. Cambridge, rather than your style and strength, means you don't have many hills hence means triple doesn't make much sense to you.

I ride a compact, but hired a triple for riding up and around mont. Ventoux and was very grateful for the extra range it gave, particularly the granny ring on the way up!

 

[GrasB]

Or location: nr. Cambridge, rather than your style and strength, means you don't have many hills hence means triple doesn't make much sense to you.

Except for the fact I got REALLY picky about having compacts because of the 5000 miles/year of Alpine riding I do I used to ride on a 30/36/52 setup but with the Alpine riding in the mix I found I wanted a smaller middle chainring with a wider cassette so the bottom chaining became redundant.

FYI your gearing range is dictated by rear derailleur wrap & most of the time generating your extra gearing range on the cassette means you get a wider gear range.

 

[PK99]

Except for the fact I got REALLY picky about having compacts because of the 5000 miles/year of Alpine riding I do I used to ride on a 30/36/52 setup but with the Alpine riding in the mix I found I wanted a smaller middle chainring with a wider cassette so the bottom chaining became redundant.

FYI your gearing range is dictated by rear derailleur wrap & most of the time generating your extra gearing range on the cassette means you get a wider gear range.

A friend who has ridden most of the alpine and Pyrenean TDF climbs, rides a compact in the alps and a triple at home in the surrey hills, where the gradients are often tougher.

 

[MrWill]

For road bike usage I could level a similar criticism at a triple.

Take a 30/39/52 chain set and 11-26 cassette the bottom chainring is too low topping out at about 24mph but the middle chainring however is too high as it doesn't allow for much bellow 12mph at a good cadence. The result is I'm constantly swapping chainrings between the middle & bottom on rolling terrain. Sure the top chainring is good for longer mostly downhill sections but then again this makes it no different to a compact top chainring.

Compare that to a 34/50 compact. The bottom chainring takes me from around 8.5 to 29mph, from 16mph up it's on the lovely tight ratio section, & the top chainring starts at about 1mph higher than the middle on the double with the tight ratios being from 23mph up. Net result is that I do a lot less shifting on a compact than a triple.

Also worth mentioning that on a triple once beyond a certain chain line deviation you're looking at massive drive train efficiency reductions. These reductions simply aren't present on road double chainring setups due to the chain line deviation not being wide enough. Another bonus for me is that I can machine my own double chainrings without issue with doubles but on triples suitable for road bikes you really need to machine proper ramps in or shifting becomes very haphazard.

It's a very personal thing. My riding style & strength means a triple doesn't make much sense to me & the larger gaps in the sprockets at the bottom end of the cassette aren't a problem in my mind.

I'm not so sure about what your saying. Just for example I'll imagine using the same 11-26 cassette. A 39 26 is really easy to push from a standstill, or even a slight gradient, and will get you to 33mph (with the same cadence you say for the 34 getting you to 29). Then the big ring is only really for descending, sprinting or trying to take off. And who climbs anything worthy of the name 'climb' at 24mph?

But yeah it seems personal. I like to start spinning at a set cadence and just click up through the gears, cadence doesn't change and before you know it, with no effort or tiredness at all your at 30 mph, slip into the 50 ring and cruise. I seemed to not really be able to do this with the compact. I felt like I was always chasing a cadence and using little bursts of muscle power in order not to loose speed when changing between chainset rings.

Have only used it a few weeks but it has left me thinking compacts are a sacrifice of something or other, be it close spacing of gears, efficiency, top end or low end.

Just to point out I am using 10 speed, and could imagine 7/8 speed would be a it pants with a triple.

 

[GrasB]

I'm not so sure about what your saying. Just for example I'll imagine using the same 11-26 cassette. A 39 26 is really easy to push from a standstill, or even a slight gradient, and will get you to 33mph (with the same cadence you say for the 34 getting you to 29). Then the big ring is only really for descending, sprinting or trying to take off. And who climbs anything worthy of the name 'climb' at 24mph?

What I'm saying is that for me there's a needless change on a triple that I don't have on a compact.

My comfortable cadence range is 60-150rpm which covers 5.5 to 34mph (or 37mph if I go to the smallest sprocket) on the bottom chainring, with the preferred cruising range of 100-130rpm it's 9-29mph. On the top chainring it's 9-54mph in my full range & 15-47mph in my cruising range. I've got 1t progression from 16mph to 29mph on the bottom ring & 23-47mph on the top chainring in my preferred cadence range. In short I have close gears where I want them but the range when I want it, I also don't end up doing shifting over 2 chainrings all the time on steep gradient rolling terrain.

A different rider with different cadence & power ranges will require different gearing which may or may not suit a compact setup. This means they'll be better off with a triple.

Just to point out I am using 10 speed, and could imagine 7/8 speed would be a it pants with a triple.

For me on triples on <8 speed make much more sense as you're starting to struggle for gear range & close ratio changes even with a triple.

A friend who has ridden most of the alpine and Pyrenean TDF climbs, rides a compact in the alps and a triple at home in the surrey hills, where the gradients are often tougher.

I'm climbing gradients in the low 30% range... considering the steepest roads in the world are in the mid 30% range it can't get much steeper until you go off-road.

 

[GrumpyGregry]

My comfortable cadence range is 60-150rpm which covers 5.5 to 34mph (or 37mph if I go to the smallest sprocket) on the bottom chainring, with the preferred cruising range of 100-130rpm it's 9-29mph. On the top chainring it's 9-54mph in my full range & 15-47mph in my cruising range. I've got 1t progression from 16mph to 29mph on the bottom ring & 23-47mph on the top chainring in my preferred cadence range. In short I have close gears where I want them but the range when I want it, I also don't end up doing shifting over 2 chainrings all the time on steep gradient rolling terrain.

I just ride me bike.

I've yet to find anything in the Surrey Hills so steep I couldn't climb it on my compact. I shall keep looking.