Compact v double

vespario

Just had fitted new ultegra 6800.

Had ordered compact but they sent double!

Only noticed on return from LBS. Has an 11/25 cassette. Will the difference between compact and double be massively different or will I just get used to it? I live on the edge of the Mendips and do hit a lot of hills!

sloppyschleckonds

Get a 26 or 27 cassette. Unless you do Draycott Steep regularly.

Speckled

Are you sure its a double, 53/39 chainrings?

My new ultegra sits in the middle of the compact/double with 52/36 rings and that came with an 11-25 cassette.

Personally if it is indeed a double i'd say send it back if you live near the hills, i stuck with a double doing most of my riding in the peak distict and it makes long rides hard work, its no fun having to get out the saddle all the time on the steep hills when you just want to sit back and cruise. Ive actually put an 11-28 cassette on and im loving the range ive got now

ai_1

The difference between a 34 tooth and 39 tooth small chainring will be very significant.
39/25 is a pretty big small gear.
Whether or not you can live with it depends on how fit you are, how heavy you are and the gradients you cycle.
I wouldn't accept a standard if I'd asked for a compact. If you don't know you want a standard then chances are you'd be better off on a compact.
You can put on a wide range cassette and reduce your small gear but a 39/28 combo still leaves you in with a bigger gear than the 34/25 you wanted and you lose the benefit of a close range cassette. Also you have nowhere to go if you need an even smaller gear which I would. I'd want 34/27 or 34/28 in the hills and you can't achieve that with a 39 chainring unless you changed the rear derailleur and put on a very wide range cassette with a 32 tooth sprocket.

Don't compromise if you don't want a standard double.
If you got a 52/36 it mightn't be such a disaster but still you should get what you bought.

imposter2.0

Speckled wrote:

Are you sure its a double, 53/39 chainrings?

My new ultegra sits in the middle of the compact/double with 52/36 rings and that came with an 11-25 cassette.

Personally if it is indeed a double i'd say send it back if you live near the hills, i stuck with a double doing most of my riding in the peak distict and it makes long rides hard work, its no fun having to get out the saddle all the time on the steep hills when you just want to sit back and cruise. Ive actually put an 11-28 cassette on and im loving the range ive got now

If the chainset has two chainrings, then it's a double, regardless of chainring size. If the cranks have 110mm BCD, then it's a 'compact double'. If the cranks have a 130mm BCD, then it's a 'standard double'.

They are all 'doubles' though - unless it's a triple, or a single.

Anonymous

Splitting hairs lol.

I thought it depended on BCD of spider.

It is technically a compact double, but most people shorten it to just compact as there is only compact double and not a compact triple or single.

Its better to call a compact double a compact and a non compact double a double.
That way if you say double, people know what you are talking about.

Mccaria

One minor point to Imposter's post. With the new generation shimano 9000 and 6800 all the chainsets work off the same 110mm BCD so either compact or standard rings can be fitted to the same chainset. It does mean you can start with one set of rings and then change later if the terrain you ride or your fitness changes. This is unlike the previous generation 7900 and 6700 where the compact and standard had different BCD as Imposter describes and so the whole chainset had to be changed. .

me-109

If you've got a written confirmation of the order that clearly states 'compact', then take it back to the shop and get the right one. They sold and fitted the wrong one, which is their problem, not yours.

Anonymous

I am thinking of getting 52/36 chainrings on my next bike .
Should be great with an 11 speed cassette.

Speckled

Carbonator wrote:

Splitting hairs lol.

I thought it depended on BCD of spider.

It is technically a compact double, but most people shorten it to just compact as there is only compact double and not a compact triple or single.

Its better to call a compact double a compact and a non compact double a double.
That way if you say double, people know what you are talking about.

Indeed, no point getting too technical!

And im really happy with the gearing i have now, i moved up from 10 speed 105 and this is so much smoother

imposter2.0

Carbonator wrote:

Its better to call a compact double a compact and a non compact double a double.
That way if you say double, people know what you are talking about.

You think it's better to be inaccurate, rather than accurate? You might think you know what you're talking about, but there's no guarantee anyone else will. Or just use the correct definitions, and remove all doubt.

The convention is (and always has been) 'compact' and 'standard' - not 'compact' and 'double'. As you said yourself, the definition depends on the BCD of the spider, not the size of the chainrings.

Anonymous

No I do think its much better to be accurate. I guess saying 'compact' or 'standard double' is the best solution these days* generally.

Thing is that a double was called a double (not standard double) before compact came along so there is an argument to say thats what it is called.
As there is only one type of compact it is not really necessary to say 'compact double' so that leaves you with 'double' and 'compact'.

* If all BCD's are going to be one size it will become irrelevant soon anyway as ultimately its that we are talking about, not the chainrings.

Some people think that compact is describing the smaller chainring of the two so I guess it depends on who you are speaking to and how the conversation is going as to how best describe gearing.

There are times I say 'standard compact' (50/34), but most of the time I just say 'compact' unless i am comparing it to 52/36 or 46/36 etc.
You could just refer to chainring sizes to be really accurate but that would be unnecessarily confusing to a lot of people a lot of the time.

cesco

Ai_1 wrote:

[...] you lose the benefit of a close range cassette.

Would you care to explain those benefits please?

Serious question, as I am in the market for a new bike. I remember switching from an 80's 6-speed to a 8-speed Sora (triple chainring, ugh) and I could never picked the right gear, especially in the beginning. I will now go to 10speed with standard double, so the idea of a wide range cassette sort of appeals to me. Cheers.

meanredspider

I'd get the compact. Going for a different cassette just spreads out the gears to overcome the problem with the small ring. I nearly ended up riding around Limburg (Amstel Gold) country with a standard double and a 25T cassette - despite being very used to hills (from the Highlands) I'd have been in some trouble as some gradients reached 20%. Fortunately the guy at my Amsterdam LBS warned me in time and I swapped the compact off another bike. Even then, I'd have been happier with a 28 at the rear on the steepest slopes. Normally I'm running a standard double and 23 cassette around Amsterdam/Utrecht as it's pancake flat.

meanredspider

cesco wrote:

Ai_1 wrote:

[...] you lose the benefit of a close range cassette.

Would you care to explain those benefits please?

Serious question, as I am in the market for a new bike. I remember switching from an 80's 6-speed to a 8-speed Sora (triple chainring, ugh) and I could never picked the right gear, especially in the beginning. I will now go to 10speed with standard double, so the idea of a wide range cassette sort of appeals to me. Cheers.

Just a smoother transition between gears so you will always be pedalling at a cadence and resistance that suits you. With a wide spread cassette, changing down May move you to a point where you are spinning from a point where you felt you were mashing. It's the difference between early automatic cars that always seemed to be in the wrong gear to modern 7 or 8 speed automatics where you hardly notice them shift.

Anonymous

meanredspider wrote:

Just a smoother transition between gears so you will always be pedalling at a cadence and resistance that suits you. With a wide spread cassette, changing down May move you to a point where you are spinning from a point where you felt you were mashing. It's the difference between early automatic cars that always seemed to be in the wrong gear to modern 7 or 8 speed automatics where you hardly notice them shift.

Good way of explaining it ;-)

ai_1

cesco wrote:

Ai_1 wrote:

[...] you lose the benefit of a close range cassette.

Would you care to explain those benefits please?

Serious question, as I am in the market for a new bike. I remember switching from an 80's 6-speed to a 8-speed Sora (triple chainring, ugh) and I could never picked the right gear, especially in the beginning. I will now go to 10speed with standard double, so the idea of a wide range cassette sort of appeals to me. Cheers.

What meanredspider said!

If you don't need a wide range of sizes then you can keep the steps between gears small.
So, for example: If you like to ride with a cadence in the low 90s and you find you're cruising at 87rpm you may want to change down one gear to raise your cadence a little. If you had a close range cassette the next gear might get you to say 93rpm. Whereas on a wider range cassette your next gear down may put you at say 98rpm. It's not a big deal just a nice to have.
I have two cassettes for my bike (it's a 9 speed triple). A 12-23 and a 12-27. I use the 12-27 most of the time because I ride in the hills fairly regularly, this will get me up a 20% gradient and I'm usually too lazy to switch cassettes between rides. However the 12-23 is nicer to use on the flats because most gear changes are only a single tooth increment at the back so you can choose your cadence fairly accurately. A 10 speed 12-25 would give similar gaps.

iron-clover

I would definitely go for the compact- I've always ridden with a compact 50-34 chainset with a 2300 8 speed 12-25 cassette, and has seen me through lots of hill climbing, but can also cope with TTs and racing. I'd happily ridden up to 30% inclines, although 20% and over are always hard, and Hardknott's 33% hairpin did defeat me as I couldn't keep the front wheel on the ground.

When my first BB wore out, I had a spare standard chainset fitted, and yes, I did fairly well in a couple of flat TTs with it fitted, but when climbing a fairly simple 20% hill I could barely keep the pedals going. If you do have a standard chainset with a maximum tooth size of 25, unless you are a very good climber you will probably struggle with most hills.

wotnoshoeseh

Mccaria wrote:

One minor point to Imposter's post. With the new generation shimano 9000 and 6800 all the chainsets work off the same 110mm BCD so either compact or standard rings can be fitted to the same chainset. It does mean you can start with one set of rings and then change later if the terrain you ride or your fitness changes. This is unlike the previous generation 7900 and 6700 where the compact and standard had different BCD as Imposter describes and so the whole chainset had to be changed. .

So does this mean I can get 52/36 rings to fit to my 6700 series Ultegra compact 50/34?
Or even keep the 50 and run a 36 inner chain ring?

imposter2.0

wotnoshoeseh wrote:

So does this mean I can get 52/36 rings to fit to my 6700 series Ultegra compact 50/34?
Or even keep the 50 and run a 36 inner chain ring?

110mm BCD rings are available in sizes bigger than 34/50 if that's what you mean. I have previously run 52/38 on a compact crankset..

Pross

EDIT

Ignore me, I was talking crap! Seems the latest Shimano stuff does somehow accommodate 110 and 130 chainrings!

Mccaria

wotnoshoeseh

The 6800 and 9000 rings will not work with 6700 (4 arm spider vs 5 arm spider)

Praxis do rings for Shimano 7950 5 arm chainset in 52/36, expensive but don't see any reason why these wouldn't fit on 6700. Being 7950 compatible they must be BCD 110 fitting, but not cheap !

http://praxiscycles.com/integrated-sets/

Pross - latest stuff is all 110

Pross

Damn, didn't need to do my edit then . Basically, if they are 110 BCD they are compact no matter how many teeth they have.

markhewitt1978

If you've ordered a compact, then take it back and get the compact fitted! Not your problem if they've done it wrong.

All depends on your strength as a rider, most non-racers do better with a compact rather than a standard.

Vandiesel

If the words Mendips or hills come into this, go compact mate

vespario

Took advice and exchanged chainset for compact 50:34. Also swapped out cassette to 11:28. What a difference.
Loving the 11 speed ultegra groupset. Well worth the upgrade from 105!