Double to compact

[Bongo]

After the huge struggle up Honister pass i am looking to change from my standard 53/39 to a compact.

I have a camagnolo mirage 10spd, will i need any specialist tools for replacing the chainset?

Thanks

 

[bonj2]

Yes.


I'd think twice before doing it though, as you aren't going to be going up honister pass every day are you?
Compacts are iffy, as you have to use small-small and large-large to get the full range of gears. You often have to keep changing chainring all the time. Not good.

 

[woohoo]

Yes.


I'd think twice before doing it though, as you aren't going to be going up honister pass every day are you?
Compacts are iffy, as you have to use small-small and large-large to get the full range of gears. You often have to keep changing chainring all the time. Not good.

Bollox. The full range is gained by using small (chainring)-large (rear cog) through to large (chainring) - small (rear cog) combination.

A small-small will fall somewhere in the large chainring range and a large-large will fall somewhere in the small chainring range, thus in no way extending the total range of gearing.

 

[gbb]

There is a compromise with compacts...
If it were me, and i had an occasional route that was a barsteward, i'd fit a compact and get a spare 40T inner ring.
The 40T would be my standard inner....then when i was going to really need it, fit the 34T. It only takes 15 minutes.

Thats assuming i wasnt going to be doing it every couple of days...you'd soon get fed up of changing them. But...if it were an occasional ride up a big one ?

Bonj is right tho...the change from 50 to 34 isnt smooth. I always used to have to double shift on the back..pain in the rear. Ideally, you want to be shifting from one to the other as rarely as possible.

 

[gbb]

Bollox. The full range is gained by using small (chainring)-large (rear cog) through to large (chainring) - small (rear cog) combination.

A small-small will fall somewhere in the large chainring range and a large-large will fall somewhere in the small chainring range, thus in no way extending the total range of gearing.

There may be better cassette ratios with compacts that aid shifting, but i found on both my compacts that where-ever i was on the rear...as soon as you shift onto the small chainring, you spin like the clappers.
I tried it in all the gears across the range...certainly on mine, there was NO easy shift without spinning like a madman, thus requiring a double shift.

To that end, i dumped the 34 and fitted a 40. Instantly better. But then, my terrian doesnt require a 34 anyway.

Perhaps (i'm guessing here) that some compact chainset / cassette combo's are better than others...cos mine were cr@p.

 

[Tel]

I wondered how the compact gearing set ups worked. I figured that the cassette spacing must be something like an 11-20 (10spd) giving you reasonable gears on the small ring.

34t is what I would expect to find on the inside of a triple chainset, which I think I'd prefer to a compact set up. Or perhaps you could have a granny gear via your cassette set up 39x28 gives you a gear of about 36.7" which is equivalent'ish to 34x25 but it will always be there and you can keep all your other gears for the rest of your ride...

 

[woohoo]

I wondered how the compact gearing set ups worked. I figured that the cassette spacing must be something like an 11-20 (10spd) giving you reasonable gears on the small ring.

A 20 would give you a bottom gear of 46 (with a 34 chainring) which many people would consider to be a high bottom gear.

34t is what I would expect to find on the inside of a triple chainset, which I think I'd prefer to a compact set up. Or perhaps you could have a granny gear via your cassette set up 39x28 gives you a gear of about 36.7" which is equivalent'ish to 34x25 but it will always be there and you can keep all your other gears for the rest of your ride...

30t is the normal/typical size of a triple's inside chainring

 

[Sittingduck]

I was worried about getting a compact on my road bike but so far it's been okay. Manage to keep it in the large chainring the vast majority of the time (just don't use the largest 2 sprockets). Shift down to the smaller chainring for hills mind...

Only a couple of times have I really wished I had a triple (so far)!

p.s. I have a girlish 13-26 10 speed Mirage cassette, which may explain the above.

 

[Marin Maniac]

I have a 36/50 compact with a 12-25 cassette and I have to say when changing up to the big ring from whilst in the middle of the cassette the change is smooth alomost like as if I were staying on the small ring but changed down to the next smallest sprocket at the rear.

 

[GrahamG]

I'm a big triple fan for the reasons mentioned above regarding double changing and chainline which both drove me nuts for the short while I ran with one. I think, if for some reason you don't want a triple, a standard double set up but with a 12-28 (or is it 29?) like campag offer is a better way of getting lower gears.

 

[MartinC]

After the huge struggle up Honister pass i am looking to change from my standard 53/39 to a compact.

I have a camagnolo mirage 10spd, will i need any specialist tools for replacing the chainset?

Thanks

Bongo, assuming it's an Ultra Torque chainset and you're just going to replace it with another one (so you can leave the bearing cups in the bracket shell) then all you'll need is the special Allen key to undo the the Hirth joint in the middle of the crank axle.

If you want to change to a different chainset you'll need the socket/spanner to undo the Campag bearing cups and tools to install your new BB.

To summarise the Standard/CT/Triple debate:

A standard won't give you the lower gears you want.

A 13-29 cassette with a 50/34 compact chainset will give you pretty much the same range of gears as a 13-26 cassette with a 50/40/30 triple. The triple will have more and closer spaced gears. The compact will have a simpler, lighter set up with a slicker front shift (compared to a triple which will also need to be trimmed as the chain moves across the cassette). With the compact when you change at the front you'll probably need to make a rear gear change too. A triple with a 29 rear sprocket will give you the lowest gear.

So you pay your money and you take your choice. It's worth working out where the gears you use most will be on the new setup and whether using them will involve a lot of double changes

If you've got a short mech on the rear changing to a compact is the cheapest option top get what you want. If your mech has a medium cage you could change to a 13-29 cassette if you're not already using one.

 

[Bongo]

Okay guys thanks for confusing things for me even more.

Without looking i think it is 12-25 on the back, will changing to a compact even make that much difference?

What about a triple?

 

[Sittingduck]

Why not get a compact chainset second hand and give it a try - I'm sure there will be quite a difference. A triple would mean a new bottom bracket and front mech - I think!

 

[Joshgav]

Go for the compact if you want lower gears, it's the easiest and simplest way to do it.

I find I rarely need to come out of the big ring when on the flats and slight uphills, then drop down to the smaller one for those times when I am tired or going up a larger hill. 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.

 

[jimboalee]

Without looking i think it is 12-25 on the back, will changing to a compact even make that much difference?

What about a triple?

So you've got a 53/39 chainset and a 12 - 25 cassette. What's wrong with that?

So the gradient goes to 25%.

Don't change your bike, that's defeatist in my book.

Go back next week and do it again. Then again the week after, and the week after that.
If you still struggle, spend some money on a smaller inner ring. If you start finding it easier, then spend the money on trousers with legs big enough for your new quads.