[andykrow]

Hey all,

So I have an e13 drs guide that uses the bb mount - no iscg tabs on my bike (Brodie Thumper.) After every couple rides it rotates back towards the swingarm, generally far enough so the swingarm actually contacts it a bit when the bike is at full extension. The other day I looked down and the swingarm had actually bent the plastic parts of the guide off to the side making my granny gear unusable. Fortunately the drs is pretty flexible so I could bend it back.

Anyway, how do I prevent this? I'm using a holzfeller/howitzer setup and cranking that bb down as hard as I feel comfortable doing. It's a 68mm width so the drive side has the spacer against the frame, then the guide and then the bb cup. I don't think it will line up right if I have the guide directly against the frame. Also, I'm definitely not hitting rocks or anything that would cause this to rotate.

Any ideas? (Other than welding on iscg tabs...)

 

[aenema]

had similar setup in past

And it did the same thing until I tightened that bb as snug as I could physically get it. pull the crank, lay the bike on the ground so you can put your weight into you bb tool and go to town. I was worried I would make it a permanent part of the frame but I was always able to remove when I needed to.

Give'r hell man.

 

[downhiller12345]

http://forums.mtbr.com/showthread.php?t=342481

 

[andykrow]

I saw that thread but it's mainly about assembly and I know how to put the thing together (I built the bike...) Those pics though look exactly like what mine swingarm was doing to the guide. The issue is no matter how hard I tighten it down it seems to rotate, and it's not from hitting rocks or anything. IDK, I'll try really laying into next time and see how that goes. Probably need a socket for the bb cup instead of a wrench... those don't look good for loads of torque. Should I worry about stripping my frame threads...??

 

[aenema]

frame threads should be fine, never had an issue there

Get the proper tool for the bb cup and just be careful not to strip the bb out. That is why you lay it on the ground and put your weight into it. Press the tool into the cup and keep it from stripping. You may get an 1/8 turn, maybe more but it should help if not solve issue.

 

[andykrow]

Yeah I have one of those wrenches for external bb but the sockets get a lot more contact on the splines. Meh...I'll try it with the wrench anyway and just be careful... I can definitely put a lot more torque onto that cup than I was before... Any technique for keeping the guide from turning while I do this? Tends to get turned too far from the chainstay.

 

[aenema]

Good question

I used a piece of plywood to wedge between the roller and the stay. Just look for something you can use as a stop to wedge in someplace.