Shifting- compact vs normal cranks

I’ve got a compact crankset on my CX bike and I have to say I was keen to try out a compact crank for the first time. I’ve got a standard Ultegra 6700 39/53 on my road bike and the front shifting is awesome- click, bang it changes without fuss. The thing is, I’m finding the shifting on the CX bike to be really crap compared to the road bike- really crunchy and sometimes struggles with the huge difference in chainring size.

I’ve never ridden a compact before so I was wondering whether this is normal since the chainring size difference is larger? Perhaps if I went hardcore CX and got a 46T chainring it might help.
Another thing I was thinking is the cable routing is different from a road bike- does that pulley thing on the seat-tube introduce more friction perhaps?

Thanks

Yes to the cable run thing- had all kinds of issues on a Kinesis CX frame i got a few weeks ago- ended up using some very NOS stock outer to make up for the sharper curves the rear cables are put through for top tube rear cable run.
You’re in Brisbane aren’t you?

I was trying to run nice alligator teflon cable casing but they have no bend in them at all- a mate is having a very similar issue with his TT bike and crap gear change- we were going to try some of the old casing on that too

What groupset are you running & what rings up front (50/34)?

Do you have a compact-specific derailleur up front?

I have a compact on both the roadie and cx bike. Zero problems.

Shitmano 105 5750 crank 50/34T with DA 7900 front derailleur. No compact specific derailleur for Shimano.
On paper it should work no problem. Maybe I’ve been spoilt with the awesome Ultegra 6700 hollowglide chainring…

I have almost the same set up on my commuter 2011 105 compact cranks but with a 2004 DA 7800 front derailleur and it works fine.

Maybe get a new bike?

Could be that simple, doubt that a 105 derailleur would work any better? I had a low-end FSA compact setup on the commuter pig for a short time, it was pretty ordinary. I sometimes bung a carbon chorus compact on the old paconi and it’s silk.

The shifting does work- it’s more that it’s ‘slow’ ie it requires sometimes more revolution of the crank to get the changeover to occur. It’s like the higher end cranks have more shifting pins and the 105 crank only has one. The Ultegra shifts in what seems like a quarter revolution of the crank, whereas the 105 sometimes you need to completely revolve the crank.
I’m just guessing here :slight_smile:

Shimano Front Shifting is generally good across the range so I don’t think it’s the quality of the cranks. Could be set up i.e FD height angle but it sounds like a sticky cable run try some gore inner and outer it’s awesome.

Yeah heard lots about the Gore cable. Some people say it’s a rip off, others saying it’s amazing etc. Maybe I could buy one length and give it a shot.

I think what I really need is Di2…

Yeh, that’s probably your best option at this stage.

Any excuse… Or else Campag or SRAM

I hear single speed drive trains often remove the hassle of cables and shifting.

You again?!

Mr

I have a compact on both the roadie and cx bike. Zero problems.
How helpful

Next time your SRAM chain falls off I’ll have something smart arse to say… :slight_smile:

I await with bated breath Horatio. Make sure you wear a shirt. I don’t think I’ll be able to contain myself otherwise.

LOLZ

You cant deny, He’s got a point.

Can’t someone just agree with me that shifting on a compact crank is shitter than on a standard crank? I’m sure I’ve read it somewhere…

I had 50/34 and now 48/34 FSA cranks and Ultegra mech/STIs, shifts perfectly, even covered in mud.

Shimano are doing CX front mechs to suit the different chainring setups now too btw.

Yeah compacts dont shift as nice as far as i’m concerned.
FSA compacts are the pits. I use a 36t lower ring which improved it heaps.
You could also change to a 46t or 48t big ring if you are going to use it for cross only.

On the front mech’s, I so looking forward to fucking off the stupid pulley as soon as my top pull mech arrives.

E

just leave it in the big dog and grind!