[el_gordo]

I purchased a 2005 MkIII frame earlier this year and built it up. I've gotten probably 5 rides on it but am having two huge issues:
Issue 1) Chain suck from the day I built it. With both the Evolve and Atlas cranksets, any shifts to the small ring when under pressure (i.e. climbing) results in the chain wrapping up under the front ring. The entire drivetrain is new, including the chain. I set the chain length at the standard big ring/big cog +2 links based upon the suspension at full extension (top of travel).
Issue 2) Running the big ring and shifting to the 26/30/34 cog makes the chain into a chainsaw on the bottom chain stay. I know cross chaining is bad, but no one told me it would saw my bike in half (see pictures).

Setup (all parts are NEW) --
2005 IH MK III Team frame, medium, bb chased and faced
Cranksets (I've tried two sets) --
Race Face Evolve DH w/ bash X-type (no chainsaw issue here, but then again no big ring)
Race Face Atlas X-type (spec on IH MkIII Team), currently dialed with the chainline at max out (50mm I believe).
Front derailleur -- SRAM X.Gen (spec on IH MkIII Team)
Rear derailleur -- XT
Chain -- SRAM 990
Shifters -- XT
Rear cassette -- XT (same size as spec)
Wheelset -- Mavic Crossmax XL

Chain on big ring and 26 tooth cog

Results #1

Results #2

This has pretty much driven me nuts. I am not even worried about how it shifts right now, I just want to be able to climb a hill without eating sh!t when I shift.

 

[w00dy]

Chainsuck, given the new condition of your parts, is just strange. I'm stumped on that.

The chainsaw effect might be solved by a longer bottom bracket spindle. Hopefully that wouldn't throw everything else off.

 

[el_gordo]

Chainsuck, given the new condition of your parts, is just strange. I'm stumped on that.

The chainsaw effect might be solved by a longer bottom bracket spindle. Hopefully that wouldn't throw everything else off.

Unfortunately it is an X-type BB, longer spindles not available. What I did do is throw an extra spacer on the drive side. It seems to have helped a little. I still seem to get contact on big ring/big sproket (I.e. really cross chaining the system) but I will live without one gear -- it is when I grind on three gears it doesn't work. Contact might also be an issue of bobbing -- Ska Todd mentioned that the chainline is set up to work when you inlcude sag, which means if I am going into negative sag/negative g's, I will have chain/frame contact in the problem gears.
I changed the chain to an older XT I had lying around, still getting a little bit of chain suck. I was going to give both chains a good cleaning (new and old) and try a different lube and go from there.

 

[ska todd]

Gordo, drop Iron Horse customer service a line and we can send you a THE Jet Pro to slap on there and stop the sawing effect.

-ska todd

 

[el_gordo]

Gordo, drop Iron Horse customer service a line and we can send you a THE Jet Pro to slap on there and stop the sawing effect.

-ska todd

Do you have a direct e-mail address??? I used the website interface for the orginal problem and never heard anything back from the service dept.
thanks-

 

[ska todd]

email tomb at ironhorsebikes dot com or call 800-645-5477 ext 214.

-ska todd

 

[dejacky]

I'm on the verge of buying a 2005-2006 Iron Horse MKIII and was worried when I read this first post. It's nice seeing Iron Horse support their product with good customer service, so I'm continuing with my purchase .

 

[el_gordo]

I cannot bash IH customer service -- this is my 2nd bike from them and they have always treated me right. BUT I have a issue that I believe that should not be happening in the first place -- in my mind, the engineering should not allow for continuous chain contact with the chainstay while riding (chain slap is normal), and the solution doesnt solve the problem, just covers it up (literally). FWIW, I would make sure I bought from a local dealer and ran the bike through all the gear combos with the suspension dialed in correctly to ensure my problem is an isolated one (which it appears to be).

 

[nato]

for the chain suck.. although the ring is new, I'd check for any small warping or odd looking teeth... it sounds like the chain ring is the issue, not the chain. good luck

 

[el_gordo]

for the chain suck.. although the ring is new, I'd check for any small warping or odd looking teeth... it sounds like the chain ring is the issue, not the chain. good luck

Installed two different brand new crank sets -- and two different chains, with the same result. :mumble:

But, I'm planning on installing a e13 DRS, so I suspect that will solve the problem.