[Closed] Moving to a Compact crankset - Questions

why do you want to swap?

no the rings are not interchangeable due to BCD

dont [i]need[/i] to shorten chain, but may be neater if you do.

I went from a double 53/39 to a compact 50/34, as I was struggling on the local steep hills. I also changed the cassette from 12/25 to 12/27 and it's made a massive difference.

The downside to this is I'm quite often running 50 front to 12 rear on the descents, but I'm hitting around 40mph and probably couldn't go much faster.

This has suited me, although my riding is very hilly. If it was flat, I wouldn't have changed.

I prefer it, the 50t seemed more usefull, expecialy with a 12-27t cassette I could do an entire day in the chilterns and only use the inner ring on 2 or 3 hills. So that's an advantage in a flat area where you would spend a lot of time in just a few gears without the long decents to make big gears an advantage. My car doesn't have the engine from an F1 car, so isn't geared for 200mph, my legs aren't as big as Caverndish's* so I don't need that big a gear either!

Yes rings are available, but the smaller BCD means they wont be as stiff as normal chainrings obviously.

Chain will be a link longer than nececary (assuming it was long enough before), I prefer leaving an extra link in the chain so that it's long enough to re-join without a quick link in an emergency, just press out an inner/outer link and re-join.

*well they probbaly are, but it's mainly blubber

I have a 50/34 ultegra on my bike. I don't like it at all - there's a massive jump between the rings which necessitates two shifts at the back at the same time. It really should be something like a 48/36, which combined with an 11-26 cassette should still give enough at the top and bottom end. For the OP, I can't see any reason to change from a standard.

The reason I'm changing is that the current cranks are bit of an antique - same as the ones below. The rings are getting to the point of being worn out so I bought some 105 with an external BB from the forum, I neglected to check if they were standard or compact :oops:. So I've got them now and I thought I'd givem them a go.

I'm running at 11-23 cassette and my most comfortable gear is 53 - 17. So my thinking is with a compact I'll ride more on the smaller cogs and have more in reserve. Until I fit it and do some rides I won't really know.

[img] &res=landing[/img]

I ran a standard, then a compact for a few years, and have been riding a standard again for the last 12 months or so.

Pros of the standard is the nice gap between chain rings, and the 39 is useful in a fair amount of situations. Cons are that I spend a lot of time in the 53/21 53/19 53/17 sort of area. 39/27 will get you up anything but can be a bit of a grunt. And of course it looks like a proper bike.

Pros of the compact are that you can basically stay in the 50 all day, and a lot of the time you'll be on a nice close ratio bit of the cassette with a better chainline if you are not generating monster power numbers. Cons are when you shift down to the 34 you feel like road runner and the bike stops unless you double or triple upshift. And they look rubbish.

That said, I'm changing back to a compact, mainly for the 50. I'm going to swap out the 34 for a 36 or 37 to get rid of that big drop in gear. That should cover all bases for a reasonably fit rider. You'll not be spinning out 50-11.

Cheers Ianpv, I was thinking the same of getting rid of the 34 for a 36.

What you really need is a triple. Lots of big gears, enough in the middle and plenty of tiny ones to winch you up the steepest climbs.

What? What did I say?

😀

50-36 works well for proper riding. for commuting (which is invariably slower) i find it massively annioying because i spend a lot of time hovering arround between the rings. seem to change at the front a lot.

I've never ridden a standard but can +1 what the above have said regarding the need to upshift 2 or 3 when dropping to the small ring.

I spend most of the time on the 50 and went 11-23 on the back, hadn't considered a 36 on the front...

ourmaninthenorth - Member
What you really need is a triple. Lots of big gears, enough in the middle and plenty of tiny ones to winch you up the steepest climbs.

What? What did I say?

I'll get a triple when I'm 60, but until then a double will do me just fine.

I've gone back to a double for the above reasons of annoying gearing between 50/34. I'm now running 53/39 with 12/25 and now find the gearing a lot more user friendly.

I don't really utilize the higher end gears on the 53 ring but that's better then forever changing between rings IME.

What you really need is a triple. Lots of big gears, enough in the middle and plenty of tiny ones to winch you up the steepest climbs.

I have a triple on my audax/ winter bike. IME, it's the only way to get close ratios and a wide range at the same time.

Trying to put a triple on my GF's bike at this moment, but the Ultegra STI's are only for a double. Sorry for the thread hijack, but anyone want to swap for some triple STI's?

I've got 105's triple, I'll be happy to swap

I used to have a triple on my road bike but stopped using the inner ring - now use a standard and have a compact for long hilly days. Quick swap.

Have a triple on my winter/commuter/do everything bike. Have no issue with them.

fourbanger - might be interested. Mail me.

I'm going to swap out the 34 for a 36 or 37 to get rid of that big drop in gear.

Don't know what chainset you have or are thinking about, but in my case I've just read that Shimano don't do a 36T ring in 110mmBCD.

Don't know what chainset you have or are thinking about, but in my case I've just read that Shimano don't do a 36T ring in 110mmBCD.

Pretty sure TA and Stronglight do...

Haze - Member
I'm going to swap out the 34 for a 36 or 37 to get rid of that big drop in gear.
Don't know what chainset you have or are thinking about, but in my case I've just read that Shimano don't do a 36T ring in 110mmBCD.

[url= http://www.wiggle.co.uk/fsa-super-road-shimano-7900-46-53t-chainring/?utm_source=google&utm_medium=base&utm_campaign=uk&utm_content=FSA-FSA_Super_Road_Shimano_7900_46-53T_Chainring-Titanium ]FSA do some[/url]

Cheers for the links, will try one out 🙂

You can get a Stonglight 38T for around a tenner. My latest geared commuter is running 50/38 compact with 12-25 cassette and it's pretty much spot-on. I spent ages experimenting with 52/38 standard and tried the usual 50/34 compact etc etc, but the bigger inner ring on the compact helps reduce the gaps and the lower BCD gives massive scope for changing both ring sizes over a (relatively, compared to standard) huge range.

I changed the cranks over last night andhis mornings ride in I was using 50:14 and it felt very comfortable. It's a pretty flat ride in so there was no need to change. My work rate didn't seem any different to riding in a 53:17.

So I'm getting more inches and it's easier to turn the cranks, bit of a win so far. 😀
[img] http://farm8.staticflickr.com/7176/6985321434_e5899555e4.jp g" target="_blank">http://farm8.staticflickr.com/7176/6985321434_e5899555e4.jp g"/> [/img]

So I'm getting more inches and[b] with the massive tailwind[/b] it's easier to turn the cranks

To go at the same speed with a higher ratio you must have been turning the cranks slower..... if that feels easier/fits your natural cadence better, then great, but you're not getting something for nothing.

Triple FTW!

Enables a big enough gear to go fast, without any big gaps in the ratios/between rings.
Plus, it has the advantage on not destroying my knees on 15%+ hills.

eyerideit - Member
Morning all,

I'm about to swap my Standard cranks for a compact set and I'm not sure it. [b]Mainly ride in and around London/Essex[/b] so I'm not sure if it will benefit me - only time will tell.

I've got a few questions for the collective.

Have you done it and how was it for you?

I ride the same as you (I live near M25 J25) and some Herts as well I have a compact double, no issues at all.

Thing is... 50/11 is still a monster gear, it's a serious rider who finds that inadequate.

I think I'll go compact on my next road bike, the winter bike is compact, the summer bike is standard. I'd always preferred the standard, but having swapped back this time I'm not sure I do anymore, always seem to be in the 'crossover' bit.