Double/Compact groupsets

[twozeronine]

Hi

I've recently got a new bike with a 10 speed compact groupset (I've only owned triples before), and was wondering what gears people mostly use. It seems that the small ring at the front is only really suitable for climbing hills, whereas the large ring is for flats & downhill. I find that on flats I mainly use the 6th or 7th largest sprocket, any higher (or is it lower) and the chain line started getting dodgy.

Also, it seems that the largest sprocket is almost superfluous, as the chain line isn't great on either of the front rings. Does anyone use it?

Thanks for any tips.

 

[Will1985]

Too many variables here - it depends on the strength of the rider; cadence preference; terrain; wind; gearing setup.
I use very tight cassettes such as 12-21 for 9 speed and 12-23 for 10 speed which lets me use the inner ring (a 36t) more often, but then I'm a spinner.
You may think the largest sprocket is superfluous, but when you get to a mother of a climb you'll be thankful for it! For the national hillclimb I stuck on a 13-26 and crossed the line in 34x21 - far better chainline than if I'd left my usual cassette on, but then also had two unused larger sprockets.
Modern chains are capable of quite an angle with chainline - you should be able to use about 6-7 sprockets in each chainring...after that you need to think about shifting at the front.

 

[Garz]

Just to add to Wills post, particularly highlighting terrain and also load. My bike can use panniers and at some point I will use them on a light tour; this is when those seemingly unused largest sprocket or two will be utilised.

Two extremes as why you may/may not use them:

At peak fitness I find even on small hills I wont drop into the smaller front ring, so on this familiar loop I wont use it. However today when it's cold and quite windy on the same course I will utilise the smaller ring but with a smaller rear sprocket to increase my cadence without fatiguing the legs battling against the wind. This kind of re-enforces Will's other points.

 

[twozeronine]

OK thanks. I did go out today and faced a bit of a headwind, and did have to use the small ring a few times.

Regarding the chain line, maybe I'm just being a bit too fastidious about it. Are there any gears that you'd say are a complete no-no?

 

[gavintc]

Learn to spin more. I have a 50/34 chainset on the front and will typically use the small ring to start off and any gentle rise. If I am in a chain gang spinning along at around 32kph, I notice that I am in the big ring, but on a rear cog near the lower end (bigger sprocket) of the rear cassette. I do not like grinding out a gear and will usually try to keep my legs spinning at a decent cadence.

 

[twozeronine]

You're right, I don't really spin enough. What sort of cadence are we talking about?

 

[GrasB]

Given the SRAM compact chain line (SRAM place the large chainring more centrally compared to their racing double) you can use every gear on the large chainring but not the top 2 gears on the smallest chainring.

 

[gavintc]

You're right, I don't really spin enough. What sort of cadence are we talking about?

If I am lazy, it will be around 75 rpm, but if I concentrate and keep with the other club riders it is around 95rpm. It is one of the reasons, I like being in a group, the faster cadence becomes the norm and it makes it easier to keep with the pedalling pace.

 

[Garz]

Everyone will have their own cadence to suit their own comfort level, it is only when you analyse it that you start to pay attention to your real cadence. As a guesstimate I would say around 100 is the ideal 'high' cadence and below 60 is grinding. Other people will find 110+ their optimum depending on who they are but for me once I go past 100 it starts to become uncomfortable, it's each to their own.

 

[twozeronine]

I'd guess my cadence is a little bit over 60 most of the time. I tend to feel like I'm not putting enough power down if I go much faster than that, but maybe I just need to practice more at a higher cadence.

Also, thanks for the info about the chain line, Gras.

 

[Fiona N]

Given the SRAM compact chain line (SRAM place the large chainring more centrally compared to their racing double) you can use every gear on the large chainring but not the top 2 gears on the smallest chainring.

That's interesting as I was riding with a guy who had a SRAM compact and he was in the big ring much more than me (on a Campag compact) but I noticed that he used all but the largest sprocket whereas I only use 7 (of 11) at most.

 

[HLaB]

There's too many variables in the OP question. But I got a 12-25 cassette and a 30/36 chainrings and I like to stay in the big ring and only drop to the small ring when I need it. That's me though and it may be completely different for you.

My standard double on my other bike has the same size of cassette (12-25) and again that provides enough range for me mainly to prefer staying in the big ring (52). Having said that on Saturday my first club run I decided to mainly use the smaller ring (38) and spin my way round.

 

[andyhunter]

53-39 and 11-25(11sp), i find it works generally all round uk though certain races i will change the cassette and front chain rings to suit steep climbs or flat.

 

[iAmiAdam]

I don't use a compact, i'm on old school 52-39, but then there's no hills around that can't be done on it. I use the 52-16 most of the time, if there's a headwind for a long time, I might spin.