Compact - All rounder?

CRAIGO5000

Hi guys, I've searched and still can't find the answers I'm looking for.

I'm about to buy a Ribble and can't decide if I should go compact or stay with a double chainset?

I currently run a 53/39 double with 8 speed 12-25 cassette and on the flats it transitions quite nicely between gears allowing desired cadence to be achieved. However, on +20% gradient climbs I'm struggling in the 39/25 gear and need a few more cogs which led me to believe I needed a compact but other advice says I should get a standard double with a 11-28 cassette for the hills?

I don't know anything about ratios, but ultimately I want the cadence smoothness on the flats that a 10 speed double could provide but also don't want holes with a cassette range that is too much?

Can anyone simply say - you need a ??? cassette with a compact and you'll be fine.

I notice that Planet X only sell their RT-57 with a 50/34 compact and an 11/25 cassette. Would this make a good combo for fast flat speed, smooth transitions between gears and the ability to climb those +20% gradients!

Cheers,
Craig

nickel

I run a compact with 50/34 and a 12-25 cassette and find it's a perfect combination, the ratios are close enough on the cassette so there's no big gaps between cogs and 34/25 is plenty low enough for even the steepest of climbs. Switching to 12-28 cassette would be a cheaper option but would leave you with gaps between certain ratios.

logitech208

I also run a compact with 50/34 and a 12-25 cassette and find it covers all my needs perfectly, its low enough to spin up the hills if needed.

Wirral_paul

I'm running 53/39 and a 12-25 on both bikes but am watching a 50/34 compact at the moment on Ebay (finishes later this evening) for my winter / training bike. I personally want to keep the fairly close ratio's but simply lower the whole gearing. Cant remember the last time i used the 53-12 combo - even downhill!! A 50-12 is pretty much identical to 53-13 anyway so this will be high enough. Gain the extra lower gearing from using the 34 chainring, but still have plenty at the top, and close the ratios inbetween.

Seems ideal to me really!! Go for it - i doubt you (or I) will look back

ShutUpLegs

CRAIGO5000 wrote:

I currently run a 53/39 double with 8 speed 12-25 cassette and on the flats it transitions quite nicely between gears allowing desired cadence to be achieved.

You may lose this with a compact, constant shifting to get the right cadence.

CRAIGO5000

I get it now. The 50 big ring of a compact teamed with an 11-tooth cog on the cassette would give me approx the same top gear I currently have (53/12) BUT I'm also going from an 8 speed cassette to a 10 speed so should gain more cadence control so long as I don't go too extreme with the cassette range. If I go for an 11-25 10-speed cassette, I should have the ability to find smooth cadence gearing when on the 50 ring and flat roads. When I change to the 34 ring, I have the advantage of a 34/25 combo for really steep stuff.

So a 34/50 with 11/25 cassette should suit me well?

Wirral_paul

Changing to the 34-25 lowest ratio is equivalent to having a 29 tooth sprocket on with your 39 chainring

CRAIGO5000

Right that's settled it then. I've been reading some more about 11-25 cassettes on compacts and even semi-pro racers don't manage to get into 11 in all but the longest downhill stretches.

What's important to me is cadence, a smooth range on the the flats with the ability to climb steeper hills.

I'm going for the 12-25 10-speed cassette and 34/50.

Thanks alot for all your input guys, it's been a good read!

rolf_f

If I have a route with lots of big climbs (eg 25% ers), I run a compact with a 13-29 and am glad of it.

I never find the gaps cause me much problem. But then, on undulating countryside if you are trying to maintain an exact constant cadence you'll be forever shifting anyway as the gradient endlessly changes. I think there can be advantages of a standard but mainly if you are in flattish country.

oldwelshman

ShutUpLegs wrote:

CRAIGO5000 wrote:

I currently run a 53/39 double with 8 speed 12-25 cassette and on the flats it transitions quite nicely between gears allowing desired cadence to be achieved.

You may lose this with a compact, constant shifting to get the right cadence.

Why constant chnging ? with a straight through 12 21 you have narrow spaces so on the flat its perfect.
I use this to race and rarely use the small ring, only for climbs so only shift on the front rarely.

ShutUpLegs

oldwelshman wrote:

Why constant chnging ? with a straight through 12 21 you have narrow spaces so on the flat its perfect.
I use this to race and rarely use the small ring, only for climbs so only shift on the front rarely.

Useful for the Road Beginner

oldwelshman

ShutUpLegs wrote:

oldwelshman wrote:

Why constant chnging ? with a straight through 12 21 you have narrow spaces so on the flat its perfect.
I use this to race and rarely use the small ring, only for climbs so only shift on the front rarely.

Useful for the Road Beginner

Not sure what your point is? but if the op finds the transition smooth using existing gears withe quite large spacing then a compact with a cassette with one tooth differences would be better and easier to find natural cadence.

Pross

You could always go compact and use a 36 instead of a 34 as the little ring (just to add to your confusion )

Chris James

oldwelshman wrote:

ShutUpLegs wrote:

oldwelshman wrote:

Why constant chnging ? with a straight through 12 21 you have narrow spaces so on the flat its perfect.
I use this to race and rarely use the small ring, only for climbs so only shift on the front rarely.

Useful for the Road Beginner

Not sure what your point is? but if the op finds the transition smooth using existing gears withe quite large spacing then a compact with a cassette with one tooth differences would be better and easier to find natural cadence.

My issue compacts is not that the gaps on a typical 10 speed cassette are too large, but that the 50/34 tooth chainrings are in no man's land. Specifically the 34 is too low for general riding. The fact you rarely use your inner ring would imply you agree, although hills are hard work on a 50 tooth ring! I don't know how hilly it is around you.

To the OP, use Sheldon Browns gear calculator see see what inch gears you use the most. Then check where they are lcoated (would it be a big/big or small/small combinatiosn on the compact?)

Also, it depends on how many hills you encounter. If you live somehwere very hilly and spend a lot of time climbing then a small chainring you can just sit in makes sense, but if the terrain is more rolling with occasional steep power climbs you might be better off with a standard chainset and a cassete that has a bail out low gear. Obviously any new bike with a 10 speed cassette with be closer spaced than the 8 speed you are currently used to and like.

I

morstar

My two penneth':

All of the different front ring combinations will give you lots of usable gears and have their advocates. The important thing is to work out which gears you need based on your riding ability and future plans and work out where on the set up they would be with each of the different chain sets. As suggested, use Sheldon Brown to do this. You want your popular gear choices to be away from the extremes of the cassette.


Standard:
Assuming you are of average fitness and not a pedigree racer, a standard will give you great gearing on flatter terrain but, it will be frustrating at certain times on hillier rides. You can force your way up anything steep but you will fatigue more quickly. This is less of an issue as you become a fitter and stronger rider. Fitting dinner plate rear gears is a load of faff to compensate for choosing wrongly now.

Compact:
Provides a huge range of gears but there is a good chance that you will find many of your most usable ratios are in the big big / small small cross chaining territory. Personally, I bought a compact in Feb last year and hated forever changing front rings for the first month. Once I blew off my winter cobwebs and got a bit of fitness under my belt, I was strong enough to ride mainy on the 50 tooth big ring and the small ring is soleley for climbing. I find this a perfect combination. I do not find it a waste of gears as I rarely used the large ring on a standard ( you don't need to use all the gears equally to keep your bike happy). The big but here is whether you will be strong enough to ride mainly in the 50 tooth front ring. If you're not, I'd actually say a triple is the best option or put a 48 tooth big ring on a compact.

Triple:
This is where snobbery kicks in. A triple is a very good solution that covers all bases at a tiny weight premium. You'll have super low climbing gears when needed but you can do most of your riding in the middle ring on the front. It's actually a very convenient solution to a common problem.

morstar

CRAIGO5000 wrote:

Would this make a good combo for fast flat speed, smooth transitions between gears and the ability to climb those +20% gradients!

In answer to this specific question...

Yes, it would, providing you mainly ride in the big ring on the front. I would suggest if your flat cruising is somewhere around 17-19mph you'll be fine. Less than that and I reckon you'll be forever changing the front ring. Of course, it all depends what sort of cadence you ride at.

ugo.santalucia

39 x 27 is a bit like 34 x 23, so if the former is not enough, a 28 won't make much difference and you do need a compact with a 27 (a 25 is not much difference).
That said, I don't like compact chainsets... the jump is too big and, while they are great up the Alpe d'Huez, they don't really work in the UK, where is all up and down, you'll have to constantly shift the front and trim the rear... a 39 gives you a bit more room, as you can keep it for that little flat before yet another small climb... with the 34 you end up spinning like crazy to go 15 mph and you constantly have to whack the chain up and down...
I started with a 39x53, went compact for two years, regretted it and went back to 39 x53

Bozman

ugo.santalucia wrote:

39 x 27 is a bit like 34 x 23, so if the former is not enough, a 28 won't make much difference and you do need a compact with a 27 (a 25 is not much difference).
That said, I don't like compact chainsets... the jump is too big and, while they are great up the Alpe d'Huez, they don't really work in the UK, where is all up and down, you'll have to constantly shift the front and trim the rear... a 39 gives you a bit more room, as you can keep it for that little flat before yet another small climb... with the 34 you end up spinning like crazy to go 15 mph and you constantly have to whack the chain up and down...
I started with a 39x53, went compact for two years, regretted it and went back to 39 x53

+1 After spending the best part of 20yrs on a 53/39, 12/25, I put a compact on one bike last year and then made the mistake of putting one on a new build. I just struggle finding a my natural cadence on a compact, i seem to be forever changing gear and using the trim, I put a 23/11 on one bike and that's helped a bit but I'll be swapping back for sure in the near future.

CRAIGO5000

Hmm. I've bloody ordered it now. :shock:

On my standard double I find I always ride in the big ring, even when setting off and slightly cross-chained. I steadily cruise at 17-20mph on that set-up but rarely use the last 3 gears on the flats. This is why I thought a compact 50t big ring with the same ratio rear cassette would work well as it's effectively lowering all of the gearing down. I was under the impression I'd be still sat in the big ring all day long but using more of the rear cassette ratio. I then have the advantage of the 34 on those +20% gradients.

Please tell me this all sounds reasonable given the above style of riding I do? I don't think I'd be ever changing the front on the flats and undulations of the country roads. BUT I will be using the 34t on steep climbs where I struggled with my old standard double!

morstar

CRAIGO5000 wrote:

Hmm. I've bloody ordered it now. :shock:

On my standard double I find I always ride in the big ring, even when setting off and slightly cross-chained. I steadily cruise at 17-20mph on that set-up but rarely use the last 3 gears on the flats. This is why I thought a compact 50t big ring with the same ratio rear cassette would work well as it's effectively lowering all of the gearing down. I was under the impression I'd be still sat in the big ring all day long but using more of the rear cassette ratio. I then have the advantage of the 34 on those +20% gradients.

Please tell me this all sounds reasonable given the above style of riding I do? I don't think I'd be ever changing the front on the flats and undulations of the country roads. BUT I will be using the 34t on steep climbs where I struggled with my old standard double!

It sounds perfect then. Compact is only a faff if you need to keep changing the front ring. You won't going by your last post.

Wirral_paul

morstar wrote:

CRAIGO5000 wrote:

Hmm. I've bloody ordered it now. :shock:

On my standard double I find I always ride in the big ring, even when setting off and slightly cross-chained. I steadily cruise at 17-20mph on that set-up but rarely use the last 3 gears on the flats. This is why I thought a compact 50t big ring with the same ratio rear cassette would work well as it's effectively lowering all of the gearing down. I was under the impression I'd be still sat in the big ring all day long but using more of the rear cassette ratio. I then have the advantage of the 34 on those +20% gradients.

Please tell me this all sounds reasonable given the above style of riding I do? I don't think I'd be ever changing the front on the flats and undulations of the country roads. BUT I will be using the 34t on steep climbs where I struggled with my old standard double!

It sounds perfect then. Compact is only a faff if you need to keep changing the front ring. You won't going by your last post.

Absolutely as above - if you're mostly on the big ring then you still will be - just you'll be typically one sprocket smaller for the same speed and road as you are now. As said, if the 34 is too small then its not dear to get a 36 chainring to raise the ratio slightly.

neeb

Bozman wrote:

+1 After spending the best part of 20yrs on a 53/39, 12/25, I put a compact on one bike last year and then made the mistake of putting one on a new build. I just struggle finding a my natural cadence on a compact, i seem to be forever changing gear and using the trim, I put a 23/11 on one bike and that's helped a bit but I'll be swapping back for sure in the near future.

Just swap the 34 ring for a 36, and with the 23/11 I pretty much guarantee you won't be able to tell the difference from a 53/39 with 12/25.

Bozman

neeb wrote:

Bozman wrote:

+1 After spending the best part of 20yrs on a 53/39, 12/25, I put a compact on one bike last year and then made the mistake of putting one on a new build. I just struggle finding a my natural cadence on a compact, i seem to be forever changing gear and using the trim, I put a 23/11 on one bike and that's helped a bit but I'll be swapping back for sure in the near future.

Just swap the 34 ring for a 36, and with the 23/11 I pretty much guarantee you won't be able to tell the difference from a 53/39 with 12/25.

That doesn't really help when the problem lies with the larger chainring, i generally spent most time on or around 53/19-17, i can see the issue with the 34 because there seems to be something missing between 34/12 - 50/23(minus crossover), there's a monster gap.

rake

Bozman wrote:

neeb wrote:

Bozman wrote:

+1 After spending the best part of 20yrs on a 53/39, 12/25, I put a compact on one bike last year and then made the mistake of putting one on a new build. I just struggle finding a my natural cadence on a compact, i seem to be forever changing gear and using the trim, I put a 23/11 on one bike and that's helped a bit but I'll be swapping back for sure in the near future.

Just swap the 34 ring for a 36, and with the 23/11 I pretty much guarantee you won't be able to tell the difference from a 53/39 with 12/25.

That doesn't really help when the problem lies with the larger chainring, i generally spent most time on or around 53/19-17, i can see the issue with the 34 because there seems to be something missing between 34/12 - 50/23(minus crossover), there's a monster gap.

whats the problem on big ring. 19-17 just equates to 17-16 and youve got the ability to go to 19 which is lower.

neeb

Yes, the 50 ring should give you almost exactly the same range of gears when paired with an 11-23 as the 53 does when paired with a 12-25, and the chain should be at about the same place on the cassette for a gear that feels the same.

CRAIGO5000

That's great to know. I honestly don't think I could personally have a better spec'd chainset now (barring triple, but let's not go there )

Staying in the 50 ring all day long using the whole cassette range on the flats with the ability to also pretty much climb anything in my region on the 34. 8)

juankerr

Yeah that's how to do it. Big ring all day long, just drop down to little on big climbs or if your knackered and riding into a big head wind!