Double to compact

[MartinC]

Sorry for the confusion. It may not get any better!

Jimbo's suggestion has some merit but it's always different strokes for different folks so it may not suit you. Your options are (in increasing order of cost):

If you've got a medium cage mech on the rear (don't worry about how you can tell - yet*) then the easiest and cheapest way to get a lower gear is to change to a 13-29 cassette. This will give you a bottom gear of 2.8 metres instead of 3.3 (assuming 700x23c tyres). This is a significant difference.

If your rear mech only has a short mech you can't do this (according to Mr Campagnolo - some might take the chance). So you could:
- Change the rear mech (for a medium cage one) and the cassette as above.
- Put a Mirage compact (50/34) chainset on the front. You might have to change the front mech as well. This is complicated - Campag front mechs have varied a bit over the last few years and there are questions about whether it's a standard or a compact mech and whether it needs to be a QS one. This would give you a bottom gear of 2.9 metres - again a worthwhile difference.
- Put a cheaper (FSA, Stronglight) compact chainset on. Effect as above but you'll need to change the Bottom Bracket (BB) too.

If you want to go to a triple you'll need to change the rear mech, front mech, chainset and BB. This will give you a good spread of gears and a bottom gear of 2.5 metres with you current cassette and 2.2 meters if you changed to a 13-29. You could climb Alps with this.

* Campag mechs come in short, long and medium. It refers to the length of the cage plates that hold the jockey wheels. Look at the Campag catalogues online (www.campagnolo.com) for pictures of different length mechs - you'll be able to tell the difference.

 

[jimboalee]

What Bongo hasn't told us yet is what bike he's riding.

What does it weigh? This has a very large bearing on what gears are necessary.

1 in 4 gradients are rare, even on major tours. Only a very sadistic organiser would route an Elite class race up a 25%.

It has been done. The Tour of Britain once went up Constitution Hill in Swansea. Lo and behold... some of the Pros and Elite class riders got off and ran with their bikes up the hill.

Another slant on this is to steer clear of any hill that is steeper than the climbs on the pro tours. Ride them for training, but don't expect to dance up a 25%.

 

[MartinC]

Jimbo, good point. I sort of assumed what sort of bike it was 'cos it had a Mirage groupset on it. I know even less about what sort of riding Bongo wants to do.

If you're racing then you need the same gears as everyone else, otherwise you get dropped.

If it's for shortish fitness/sporty type of rides then better legs may be the right objective.

If you want to do Audax/Sportive/Day Rides type of riding then lower gears can make many journeys easier and pleasanter.

I have a feeling Bongo may come out of this knowing what n+1 means!

 

[woohoo]

I have a feeling Bongo may come out of this knowing what n+1 means!

… and to help him on his way….

MartinC is spot-on with his recommendations according to the Campag instructions but I've found that in practice there is some latitude and you can get away with changing less than the instructions suggest. This is what I've done/changed over the past couple of years.

Initial set-up: 9 speed compact (50/34) chainset, Campag CT (compact) front mech, Campag short cage rear mech, 13-26 cassette, 9 speed chain.

Moved to a Triple set-up: Campag triple (52/42/30) chainset, Campag CT (compact) front mech, Campag short cage rear mech, 13-26 cassette.

Components that needed to be changed: New chainset. New bottom bracket (my bike has a 34.9mm seat tube and for Campag this means a 115.5mm bottom bracket instead of the 111mm standard size),

Components that weren't changed: Campag CT (compact) front mech, Campag short cage rear mech, 13-26 cassette, 9 speed chain.

Set-up/Usage notes: Front mech needed really careful set-up but eventually worked with no rubbing. Small-small and large-large combinations had to be avoided (they should anyway) because the chain would be too slack (small-small) or would probably have burst something on the large-large combination. The chainline with the triple was horrible because the 115.5mm bottom bracket and wider nature of the triple chainset resulted in a badly skewed chainline with the two larger chainrings in all but the 3 or 4 smallest cogs.

Final (for now) set-up: Campag 10 speed compact (50/34) chainset, Campag CT (compact) front mech, Campag short cage rear mech, 13-29 cassette, 10 speed chain.

Components that needed to be changed from initial set-up: New chainset, 13-29 cassette, new chain (all only because I switched to 10 speed).

Components that weren't changed from initial set-up: Campag CT (compact) front mech, Campag short cage rear mech.

Set-up/Usage notes: the short cage rear mech works fine with the 29 cog and small-small, large-large combinations are possible but I never use them.


So, IME, the short cage rear mech will work with a triple set-up, as long as you are careful (i.e. must avoid large-large) and will also work with a 29 cog without any problems, despite what Campag says.

The question about having to replace the front mech if you go compact or triple depends, as MartinC says, on whether your front mech is a compact-compatible type. If it is then there there will be no problem going compact and you might get away with using it on a triple.

 

[jimboalee]

If you're racing then you need the same gears as everyone else, otherwise you get dropped.

If you're racing, you need to be able to use the same gears as everyone else, otherwise you get dropped.

More to the point.

If you're racing, you need to be able to use longer gears than everyone else, and they get dropped.

 

[willhub]

I'm guessing a 39:53 would be easier on knees than a compact? For the flat anyway?

I'm thinking of changing sometime.

 

[jimboalee]

Before you go spending lots of lolly on a new geartrain, get yourself on a long stretch of road ( like a by-pass ). Ride up and down with your hands on the hoods, trying not to stop and also try to keep 30 kmh average for the continual stretches.

After ONE HOUR, you should have got in a gear that suits your natural cadence.
Calculate that cadence.

A rough guestimate for this speed on a modern roadrace bike is 174 Watts, which happens to be 0.25 Horsepower, or one horse's leg.

Chart all your gears calculating the speed for your 'natural' cadence.
When you come to the gear which is (1/lb)x1000, that is the 10% gear.
At your 'natural' cadence, that is the speed you should climb a 10% at 0.25 Horsepower.

In reality, psycology takes over and you climb the hill on a much longer gear, except for the 'Spinners' out there.

 

[Domestique]

The lowest gear I have 25 on the back with a 34 front is just perfect for spinning up that last hill nicely where my old double compact was much more of a pain.

Thats pretty much the same set up as me. When I changed from a 53/39 to 50/34 I found it a revelation tbh. I find I can now get up most hills without having to resort to out of the saddle honking
As old age gets the better of me I am sure a tripple will play a part at some time.

 

[jimboalee]

Thats pretty much the same set up as me. When I changed from a 53/39 to 50/34 I found it a revelation tbh. I find I can now get up most hills without having to resort to out of the saddle honking
As old age gets the better of me I am sure a tripple will play a part at some time.

How steep are the hills? How heavy is your bike? Quoting gear ratios means NOTHING without knowing these.