replacing triple slx with double xt crankset help please

everydayimriding

Have bought the double and am about to try and fit it. Changed from 42-32-24 to 40-28.

With the triple on, if I toggle the switch on the shifter to double it moves between the 42 and 32 only, it doesn't go down to 24.
So when I put the double chainset on, presumably the 40 will be where the 32 currently is and the 28 will be where the 24 is. Should it then be a case of adjusting the high limiting screw to prevent it going to where the 42 currently is?

Or do I need a spacer to get the right chainline? What else should I consider? Chain length?

Also, the diagram on the instructions shows rings Y1F316000 between the BB and both crankarms. However, they don't seem to be in the package from CRC. Do you think I need these?

Thanks

nicklouse

Yes you will need to totally reset the mech.

everydayimriding

Thanks for the response. I've no idea how to reset a mech so its off to the LBS I go.

Twelly

Save yourself some money and time: http://www.parktool.com/blog/repair-hel ... djustments

everydayimriding

Thanks for the link, I'll have a stab to save money. Won't save time though lol

Still concerned that I was supposed to receive those two rings in the package. It's number 5 on this diagram
http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M785-3165A_v1_m56577569830800932.pdf
Can I get away without them or do I need to contact CRC?

Thanks

Twelly

You should have recieved both external bearing cups with bearings fitted, a plastic tube that connects the two and 3 spacers (plastic, black, 2.5mm I think). If you have no spacers then you could contact CRC but I would just pop into LBS and see if they have any spare knocking about.

If you have a 68mm BB shell (on the frame) then you install the cups with 2 spacers on the driveside and 1 spacer on the non drive side. If your BB shell is 73mm, you put 1 spacer on the driveside, no spacers on the non driveside. Remember the cups are driveside/non drive specific as the threads are opposite. All of this is on Parktools of course..


EDIT: just realised what you think is missing. Part of the crankset rather than BB, I dont have that ring on either of my HT2 cranksets.

cooldad

everydayimriding wrote:

Thanks for the link, I'll have a stab to save money. Won't save time though lol

Still concerned that I was supposed to receive those two rings in the package. It's number 5 on this diagram
http://bike.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FC/EV-FC-M785-3165A_v1_m56577569830800932.pdf
Can I get away without them or do I need to contact CRC?

Thanks

They should come already fitted to the cranks.

Chunkers1980

Bet you do smellytwat

cooldad

This^^^^^^^^^^

Twelly

Ignore me I have no idea what im talking about rings there, very small and in a little groove on each arm, so barely noticeable.

cooldad

TwellySmat wrote:

Ignore me I have no idea what im talking about

No worries. We do.

mark~p

HI there,

I have just been through this on my Cube, replacing the 10 x 3 SLX with an M785 2 x 10. I also replaced the Shimano BB with a Hope at the same time.
1) Bottom bracket, the spacings are regardless of the number of chain rings, but are configured based on the width of you BB housing.
2) Front mech changer, I replaced the SLX changers to XT as well, but as I have then on another bike and the are super slick. The XT also have a selector to provide 2 way instead of 3 way. With the both the SLX and the XT, the 2 x 10 configuration used the inner and middle ring positions on the changer.
3) Front mech, depending on the size of your original large ring you will probably need to move the front mech down the seat tube a few mm. You will also need to reset the high and low stop screws. It is not difficult, it just takes time to get it changing nicely. For what its worth I am using a 24 to 40 combination with an 11 to 36 cassette. This has been great so far. The next step is to replace the standard rear mech to a Shadow+ to reduce chain slap.

Hope that helps.

taffygriffiths

the 'double' setting on the front shifter uses the "middle" and "outer" ring positions.

you have to put it into the "middle ring" position, change the shifter into double mode, and then reset the mech, so that it is on the inner ring.

basically.. what used to be positions for 32 and 42 rings, are now positions for 28 and 40.

get my drift? lol

Ofcourse, you can just use the limit screws to stop you using the 3rd position... saves some faffing!