3x10 conversion to 2x10 question

agent_red

Hi,

I have recently tried to replace my 3x10 Shimano FC-M552 42/32/24. I have replaced them with a bashguard + 36T Blackspire Middle and kept the Shimano inner 24T chainring. I am having many issues with setting up the gearing and front derailleur shifting and was wondering if this could be caused by running the Shimano alongside the Blackspire ring, would having a Blackspire inner help or should the mixing of chainrings not be an issue?

jimothy78

It shouldn't make a difference what brand you use, as long as the new ring has shifting ramps (those designed for single-ring setups don't).

Have you correctly set up the front derailleur for the new pairing? you'll need to adjust it vertically on the seat tube and then re-index it. May as well install a new cable while you're at it, unless it'd been changed very recently. Also make sure that the derailleur cage is exactly parallel to the chainrings - a little bit of a skew makes it almost impossible to get things working smoothly.

agent_red

Thanks for the reply, the middle chainring is ramped. I have got it shifting now, but its shifting onto the bashguard now and falling onto the middle chainring eventually. It also seems like the chain is rubbing on the slotted fittings that hold the middle ring and bashguard on when it is on the smaller ring. I guess its just a case of messing about with it until I get something useable, no quick wins here.

jimothy78

agent_red wrote:

I have got it shifting now, but its shifting onto the bashguard now and falling onto the middle chainring eventually.

Then you haven't set up the derailleur properly - the limit screws should prevent this.

It also seems like the chain is rubbing on the slotted fittings that hold the middle ring and bashguard on when it is on the smaller ring.

Do you mean the chainring bolts? There should be enough clearance unless you've got something out of place. Maybe take some photos to show us the problem?

I guess its just a case of messing about with it until I get something useable...

Don't "mess about" - follow the principles shown here to set it up one step at a time (I know this almost certainly isn't the derailleur you're using, but the principles and order are the same).

1. set vertical height so the cage clears the bashring by a couple of mm.
2. check outer face of derailleur cage is parallel to bashring.
3. set high and low limit screws (see pdf for more detail)
4. set cable tension (see pdf for more detail).

The Rookie

Have you used a double specific front mech with the ramped sections in the right place, or are you still using the triple one so that as it trys to shift into the 'middle ring' the chain is moving into the outer ring section of the mech?

paul.skibum

Have you got the Bash and middle rings mounted correctly? And as the others are saying, sounds like the limiters and positioning of the front mech are off.

You shouldn't need a 2 ring specific mech or shifter for what you are trying to achieve.

agent_red

It is still the original triple mech. By "mess about" I really meant repeat the setup procedure until it works, I have been following the Shimano doc as well as a couple of Youtube videos I have found. Everything is mounted correctly as far as I can see, the chainring bolts are tight a little proud of the middle chainring. I will have another go today and see what happens.

The Rookie

agent_red wrote:

It is still the original triple mech.

You'll probably need a double specific to align the ramps on the cages with the rings properly then, using a triple mech only works when you can align the ramps to the rings (so works fine for people who just keep the old ring sizes for example) so you may have some joy by raising or lowering the mech (ignore the nominal clearance to the big ring setting).