Road bike gearing -...
 

[Closed] Road bike gearing - Std vs Compact chainset

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It's time I got the 'best' bike rebuilt for summer and have started scourcing parts. Last year I built a proper winter bike, bought new frame and forks, wheels, bars etc. and built it up using the drivetrain from my 'best' bike with the intention of then rebuilding it with upgraded parts. Basically just need the drivetrain for it, chainset, rear mech, cassette, chain, stem, bar tape and cables is all I need to complete it.

The chainset/cassette combo that came off this bike was a compact 34/50 with 12-25 cassette. I've just spotted a good deal on a chainset (on the classifieds here) but it's a std 39/53 and I don't know whether to go for it or hold out for a compact. Obviously I could go for this and just stick a bigger cassette on. I've done the Sheldon Brown calculations and to get the same lower end ratio I'd have to go for a 12-29 cassette which don't seem to be available, 12-27 are in stock at most shops but that changes the ratio from 2.6 to 2.8 (whatever that means). Will I notice the difference? Just a little worried about screwing up the gearing ratios that I know I'm happy with just a save a few quid.
Any thoughts from STW


 
Posted : 04/05/2011 9:34 pm
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unless your racing you dont need a standard


 
Posted : 04/05/2011 9:59 pm
 Bez
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If you like 34/50 then stick with it, there are plenty out there.

[i]unless your racing you dont need a standard [/i]

That's as valid and invalid as saying unless you're in the Alps you don't need a compact. Use what you like.


 
Posted : 04/05/2011 10:02 pm
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unless your [s]racing[/s][b]fat[/b] you dont need a [s]standard[/s][b]compact[/b]

FTFY

I've got a compact at the moment, will probably go back to 52/38 if I see something at a good price.

Reasons not to like compact:
-The gap is huge, feels like your going from one end of the cassette to the other when changeing gear, not enough clicks in the rear shifter to do it in one motion so you lose momentum too.
-The gears are low, I can do an entire ride in the chilterns in the big ring, I'm not that fit and the hills can be pretty sharp.


 
Posted : 04/05/2011 10:08 pm
 pdw
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27 vs 29 is not huge, but probably noticeable - just under 7%. Unless you make a habit of cycling up properly steep stuff, you should be fine with 39/27.

With 12-29, you might start pushing the capacity of a short cage derailleur.


 
Posted : 04/05/2011 10:11 pm
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Blimey what's happened have all the hills in the UK got bigger over the years. When I was a lad we were lucky if we had 42x18 to look forward to...


 
Posted : 04/05/2011 10:27 pm
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unless you're racing [b]or are a cycling god like spooney[/b] you dont need a standard


 
Posted : 04/05/2011 10:34 pm
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thisisnotaspoon - Member

unless your [s]racing[/s]fat you dont need a [s]standard[/s]compact

that's fattist 😛

I said my intention was the upgrade but funds a bit tight ATM so trying to do it on a budget and looking to the classifieds for bits.

Know what you mean about the gap which is why I'm tempted with a standard. But, a bit lumpy round here, regularly ride, Wadington Fell, Nick'o Pendle, Tathem Fell, Halton Gill and mostly anywhere around The Dales. I know I can climb anything round there with the 34-25. at worst i'd be going to 39-27 😕


 
Posted : 04/05/2011 10:36 pm
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Doesn't contador use a compact ?

[img] [/img]


 
Posted : 04/05/2011 10:50 pm
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triple it is the MTBers way


 
Posted : 04/05/2011 10:55 pm
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Doesn't contador use a compact ?

Looks like a 53T ring...


 
Posted : 04/05/2011 10:56 pm
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I do love the way these threads bring out all the cycling gods who ride up lots of steep hills without the need for low gears.


 
Posted : 04/05/2011 10:56 pm
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when you were riding with a compact how often were you in the very bottom gear? if the answer is rarely/very rarely then you'll be ok with 39 and 27

39 and 27 rear is a gear ratio of 1.4
34 and 25 rear is a gear ratio of 1.6

not that different in the grand scheme of things


 
Posted : 04/05/2011 11:07 pm
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not that different in the grand scheme of things

It is if you need that bottom gear. 39/27 is pretty close to 34/23 (2nd bottom gear), and if you do find yourself still reaching for the gear lever when in that - even occasionally - you'll find not having the option frustrating.


 
Posted : 04/05/2011 11:11 pm
 Bez
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edhornby, your calculator is broken.

Gear differences aside, the main thing about a compact IMO is the jump between rings. I'd definitely have one if I lived in the mountains but I like my standard for English hills. But that's me. I don't give two hoot what anyone else prefers.


 
Posted : 05/05/2011 6:28 am
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unless your fat you dont need a compact

Or live somewhere with proper hills like the lakes - I'm not fat and I need a compact, some of these hills I'd like a triple


 
Posted : 05/05/2011 6:37 am
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I was an advocate of the 53/39 is all you need. However a winter of high miles on a compact has changed my mind. The main reason being the 50 ring being so universal. I found that it made a difference especially on undulating terrain.
I will change my cassette to a 23 max when it needs changing though.

I also agree 53/39 is best for racing, say what you like about equivalent ratios my experience shows a 53 to be best.


 
Posted : 05/05/2011 6:38 am
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I really like the 50t on a compact - 95% of my rides are done in it with a 25t cassette - but you don't need a compact to have that.

Like having the option of a 34t for really steep stuff & the once a year ride in the alps. Don't really notice the jump between rings, just give it a thumbful on the right at the same time (Campag).


 
Posted : 05/05/2011 7:33 am
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[i]unless your fat you dont need a compact[/i]

I can't believe there's been 5 posts with variations on this in it and no one has said anything about the your/you're issue.

STW isn't what it was.

Oh, and compact is great.


 
Posted : 05/05/2011 7:38 am
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Ignoring discussions about which is best I would hold out for what you really want. It will come up eventually and if you get the standard now you'll always have one eye out looking for a compact.

As to which is best I think it comes down to personal preference, where you ride and what riding you do.

I race on my compact (it's what the bike came with) and I've never found myself lacking for top end gears and being dropped because of it.
Races are generally pretty flat, I like to spin rather than push big gears.


 
Posted : 05/05/2011 7:50 am
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I've started to hate the terms compact and standard because you always end up with people arguing pointless things like "I like a 50 so I always use compact" or what gear ratio is needed for what climb. If you like 50 then you can always put a 50 on a standard 130BCD chainset. Or a 46 for that matter. Or a 38, but you cannot go any lower than 38. Likewise, if you find a 50 too low, then you can always go for a 52 on a compact 110BCD and still use something like a 36. If you find the jump between 50 and 34 too big, run a 50 and a 36 or a 38 on a compact (I use a 36 inner ring). Life is full of options.
As for the original question, if it's a great price and you need it now, then go for it. However, a compact will come along if you can wait. I'd imagine you'll get over most things with a 39x27 though although it depends on how steep your climbs are.
Finally, climbs in the UK are often far steeper than those in the alps so all this talk about needing low gears just for the alps is missing the point. It's easier to pedal away for hours in the right gear than minutes in too high a gear.


 
Posted : 05/05/2011 7:53 am
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I've got a compact on mine


 
Posted : 05/05/2011 8:53 am
 Rik
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All this talk of 'I've live in an area with proper hills' therefore I need a compact. You don't need a compact, you WANT a compact to make it easier. Which is fine.

But compacts have not been around for that long, wide ratio cassette didn't used to be common place either and the hills in the UK have not got any harder or steeper. 39/25 used to be a winter or touring gear now its 34/29 or even 30/29 on a triple.

If you want a compact that's fine - but please don't talk about needing one!


 
Posted : 05/05/2011 8:59 am
 Rik
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Oh - 72 fixed used to be standard fair too in winter and you still got up and over every hill


 
Posted : 05/05/2011 9:02 am
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I didn't say I was a cycling god.

Yes you can change the chainrings to get some sort of comprimise, but asfter shelling out £100+ on a chainset I'd rather it was right than spend another £50 on rings.

Compact + 11-23 or 11-25 gives a really good combination of gears, but even shifitng as far as it allows doesn't result in the right gear when dropping down the front, up the back.

Compact with 12-27 gives a silly gear for climbing but the bigger jumps makes dropinginto the granny and shifting half a casette on the rear about right.

Standard + 11-25 and to drop down ~1 gear from 52/25 is simply push both cable release levers and it feels like one gear. That means theres more overlapping gears, but they're more usable IMO.


 
Posted : 05/05/2011 9:05 am
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All this talk of 'I've live in an area with proper hills' therefore I need a compact. You don't need a compact, you WANT a compact to make it easier. Which is fine.

But compacts have not been around for that long, wide ratio cassette didn't used to be common place either and the hills in the UK have not got any harder or steeper. 39/25 used to be a winter or touring gear now its 34/29 or even 30/29 on a triple.

If you want a compact that's fine - but please don't talk about needing one!

Most of my bike rides go over some sort of steep hill like Hardknott, Wrynose or some other 25+ percenter. Doable on a double, but faster on a compact.


 
Posted : 05/05/2011 9:08 am
 Rik
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Hardknott and the like are hard steep climbs - but I don't see why its faster on a compact. Steep climbs like that you would not want to ride in the saddle - so out of the saddle why is a compact faster??

Doable - of course it's doable as for many years you didn't have any choice.


 
Posted : 05/05/2011 9:15 am
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I just find it faster being able to turn the cranks over a bit quicker rather than having to grind a really hard gear.


 
Posted : 05/05/2011 9:32 am
 aP
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compacts have not been around for that long,

Oh, I've been using lower gears on my road bikes for over 15 years based on 110BCD chainsets, I must be mistaken.
Ride what you want, I find that having a nice reasonably sensible low gear means that I can ride more for longer than I would with something like 42/23 so that's what I have. Other people I know like to ride huge gears - I don;t say anything because everyone's different.


 
Posted : 05/05/2011 9:36 am
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Agreed with above about being faster in the lower gears. On the steep parts of Hardknott, you feel always feel over geared whatever you have. Having lower gears, for me at least, just means you don't have to pace yourself as much and keep fresher legs.

But like I said above, it's whatever works for you.


 
Posted : 05/05/2011 9:45 am
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Don't really notice the jump between rings, just give it a thumbful on the right at the same time (Campag).

I do wonder if most of those who prefer compact are on Campag - as you say, the jump between rings is a complete non issue when you can dump a few gears on the back at the same time as shifting the front.


 
Posted : 05/05/2011 11:49 am
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Cheers you lot,

I've decided, cos I'm not racing and I am fat, I'm going to get a compact. 😛
It makes a lot of sense to stick with what I know.


 
Posted : 05/05/2011 2:33 pm
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For me as a reasonable biker but no great climber, I find a standard a bit of a handful on steep stuff even with a 27T rear. Compact allows you to spin more efficiently instead of mashing great big gears for the same speed, and is hence much easier on the legs allowing you to ride more. If you like punishment though (or are training for hill climbing maybe, or like 50rpm cadence) then double would be ok.

Personally I like a triple for hilly areas. I can hammer when I want in bigger gears or spin away. I've got the standard on now however because where I am currently is pancake flat.

Don't see the disadvantage of triples myself 🙂


 
Posted : 05/05/2011 2:38 pm
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Don't see the disadvantage of triples myself

I heard that your cock shrinks everytime you use the granny gear.


 
Posted : 05/05/2011 2:47 pm
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Triple = best of both worlds.

p.s. davidtaylforth - only someone with a tiny todger in the first place would be worried about that 🙂


 
Posted : 05/05/2011 2:54 pm
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p.s. davidtaylforth - only someone with a tiny todger in the first place would be worried about that

Thats why I alternate between a triple, and a 65tooth single ring with an 21-11 cassette, keeps it in check.

Depends how you ride though, if you just like a leisurely cruise out then a triple is fine, but if you like brayin' it up the climbs then its not worth it.


 
Posted : 05/05/2011 3:05 pm
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I have a triple on my bike. Tiny weight penalty, and in return you get close ratios and plenty of range. The 30/ 25 was very welcome when hauling up Symond's Yat last Sunday, a 1:4 climb near the end of the 90 mile Forest of Dean Spring Classic. Plenty of people were reduced to walking...


 
Posted : 05/05/2011 3:07 pm
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but if you like brayin' it up the climbs then its not worth it

It gives you the option. Plus, some climbs are so steep that you need the triple even if you are giving it the beans. At least some of us do.


 
Posted : 05/05/2011 3:12 pm
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I've never used a triple but I find my compact with a 27tooth ok for steep climbs, but you cant ease up. I guess with a triple you can sit down and rest for a short while?


 
Posted : 05/05/2011 3:15 pm
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Don't see the disadvantage of triples myself

I had real trouble getting the front mech to not rub at some point and found the 30 was too low, hence I'd grind up stuff in 42/25 rather than change down.
Compact solved both issues, and as I wasn't really troubling 52/11 very often it made more sense. To be honest it was the rubbing that really got to me.


 
Posted : 05/05/2011 3:16 pm
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Compact is similar to triple in spread really. Only reason I don't like compact is the jump between the rings.


 
Posted : 05/05/2011 3:17 pm
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Triple STIs usually have a trim function to solve front mech rubbing. And in my book, a 10-tooth jump between chainrings is much more sensible than 16.


 
Posted : 05/05/2011 3:21 pm