Chainguide on MKIII

[mfoga]

Anyone install a chain guide on a MKIII. I got a Blackspire dew lite for mine. I had almost never used the big ring on a trail and had bent a tooth already on a rock. So since I was going to get chain guard I figured I would get a guide too.

I was able to install it but the chain is rubbing on the guard unless I put the original spacer between the guard bracket and the bottom bracket cup. But then with the spacer there too the spindle doesn't stick out as far. Is this ok, is there a minimum amount that needs to be in the other crank. With the original setup the spindle would stick out so the whole splined portion is sticking out.

[Dino Brown]

1) A picture is worth 1,000 words ....
2) The IH, All Mountain (or) DH Forum on MTBR may be helpful sources of info
(*Yes, I did notice you posted a similar question in the IH forum)
3) The crew at The Path Bike Shop know all about MKIII's.... Call or visit them!

Nice bike.... Nice idea!!!

[CalEpic]

What type of cranks are you running?

[northshore]

Originally Posted by CalEpic

What type of cranks are you running?

'07 OEM is the FSA Moto cranks.

I currently have problems with chain drop as well in the middle ring when going down trails like Rock-It or Lynx.

[DBD]

I believe the MKIII does NOT have ISCG mounts, correct?

So you are using the BB mount system which means you need an E-type bb to get it to fit properly or you need to get a longer spindle in the bb.

[northshore]

Originally Posted by DBD

I believe the MKIII does NOT have ISCG mounts, correct?

So you are using the BB mount system which means you need an E-type bb to get it to fit properly or you need to get a longer spindle in the bb.

I believe that is correct, the MKIII does not have a ISCG.

[CalEpic]

I'm not familiar with FSA crank arm mounting. If it uses either a bolt or pinch bolts, I can't imagine that 2-3 mm would make that much difference but I'll have to defer to those in the know.

[northshore]

Originally Posted by CalEpic

I'm not familiar with FSA crank arm mounting. If it uses either a bolt or pinch bolts, I can't imagine that 2-3 mm would make that much difference but I'll have to defer to those in the know.

Uses a pinch bolt to hold the crank arms on and a through bolt type on the non-chain ring side to keep it together.

[Pato]

I'm not familiar with FSA crank/BB setup, but this is how outboard BB Shimanos work. They come with three 2.5mm spacers to allow for the compatibility with different BB shell widths and derailleurs. For a 68mm BB shell two spacers on the drive side (one if you are using an E-type front derailleur) and one on the non-drive side. For a 73mm BB shell one spacer on the non-drive side (none if you are using an E-type front derailleur).

If the FSA cranks use spacers like Shimano then you can just replace the inner most spacer with the chain guide arm then torque the cups to spec. What size BB shell does the MKIII have? If its a 68mm then no ISCG tabs or E-type specific bottom bracket required.

[northshore]

Originally Posted by Pato

I'm not familiar with FSA crank/BB setup, but this is how outboard BB Shimanos work. They come with three 2.5mm spacers to allow for the compatibility with different BB shell widths and derailleurs. For a 68mm BB shell two spacers on the drive side (one if you are using an E-type front derailleur) and one on the non-drive side. For a 73mm BB shell one spacer on the non-drive side (none if you are using an E-type front derailleur).

If the FSA cranks use spacers like Shimano then you can just replace the inner most spacer with the chain guide arm then torque the cups to spec. What size BB shell does the MKIII have? If its a 68mm then no ISCG tabs or E-type specific bottom bracket required.

73mm

[mfoga]

Originally Posted by DBD

I believe the MKIII does NOT have ISCG mounts, correct?

So you are using the BB mount system which means you need an E-type bb to get it to fit properly or you need to get a longer spindle in the bb.

Whats the difference between a regular and e-type BB? I look at the FSA site and I can't find it say it has an e-type extrenal but the install instructions say this about my BB.
Model No. / Model Name BB-7000 / MegaExo Bottom Bracket for alloy MTB cranks
o BB Shell 68mm / 73mm English (BC1.37”), including E-type

I have looked and can't find a bb-7000 e-type anywhere. If I can just change the BB to one that will work and can still use my cranks I have I would be happy to buy a new BB at this point.

[DBD]

Originally Posted by mfoga

...
I have looked and can't find a bb-7000 e-type anywhere. If I can just change the BB to one that will work and can still use my cranks I have I would be happy to buy a new BB at this point.

E-type bb have a lip that is used to hold E-type dérailleurs on and designed so the chain line is still good.

Going off what Northshore said, since you have the Moto cranks, set it up and take a pic so we can see how the chain is rubbing. Post the pic as Dino suggested or go to a shop.

The set up should be

1) BB shell (frame)

2) Guide - replaces a 2.5mm spacer

3) 2.5mm Spacer (if needed)- there should be enough spindle for the non-drive side to mount to but with out seeing the bike I could not say for sure

4) Cranks

You also need to be sure the chain line works or you will be getting miss shifts and could bend a cog or two in the rear.

If you are unsure hit the shop and ask them to set it up.

[Pato]

After checking the installation instructions from FSA and Blackspire, since you have a 73mm BB shell, there should be no spacers BB spacers used during the install.

Where is it rubbing and is it rubbing in all gear combinations with the small ring or just the small ring and the last few granny gears in the back? If it's just rubbing near the guide rollers, perhaps you can rotate the guide plate counterclockwise a bit to clear the rub. If it's a FS frame you may not get the rubbing once you actually get on the bike as the sag will cause the chain to rise up above the top of the guide plate.

Like others have said, pictures would help a lot here.

[mfoga]

Ok here are few pics.

First just with the non drive side off. .57 inches of shaft sticking out.


Now with guide plate on. This is with the small front ring and middle ring in the back.


Now with guide plate and original spacer. There is about .05 inches between chain and guide plate.


The Shaft now has about .45 inches sticking out


I know they say the chain line should be 50mm but is about 53mm this way.

[CalEpic]

Was there originally a spacer on the non drive side? If there was, I would ditch it as DDB said.

[mfoga]

Originally Posted by CalEpic

Was there originally a spacer on the non drive side? If there was, I would ditch it as DDB said.

No spacer on non drive side.

[northshore]

You sure you ordered the non-ISCG version?

Instructions for a Kona stinky (non-ISCG): http://forums.mtbr.com/showthread.php?t=269460

[mfoga]

Its a bottom bracket mount. I also pulled the whole bottom bracket out and the center section says 73E which is what they show on the FSA site as the 73MM E bracket designation and can mount a chain guide to. I am thinking the problem is with the bracket design not the bottom bracket. I may try and take my bike to a shop on friday.

[Pato]

If it's just rubbing on the top part of the chain guide you can either try rotating the guide counterclockwise a bit. If this is not possible then maybe grinding the plate down a few millimeters at the point of contact might work. I know some guides require a bit of custom modifications in order to work with some frames.

I wouldn't risk mounting it with the spacer in there. The non-drive side crank arm may not have enough contact to make a solid connection. At best it may keep coming loose on you. Worst case scenario it could strip the spindle/arm interface rendering the crankset useless or bodily harm if you wreck.

[northshore]

Originally Posted by mfoga

Its a bottom bracket mount. I also pulled the whole bottom bracket out and the center section says 73E which is what they show on the FSA site as the 73MM E bracket designation and can mount a chain guide to. I am thinking the problem is with the bracket design not the bottom bracket. I may try and take my bike to a shop on friday.

I was reading a short post on MTBR and one guy mentioned he switched from a BlackSpire to a DS-1 which worked out better for him but didn't mention a reason why.