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'Over' bottom bracket cable routing

Posted: Sat Oct 13, 2012 1:38 pm
by Lots of steel bikes
Hi everyone, I'm putting together my first 'over' bottom bracket build. The cable is touching the seat tube. Is that unusual? Shimano 600 FD. Cage in line with chain ring.

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Re: 'Over' bottom bracket cable routing

Posted: Sat Oct 13, 2012 3:26 pm
by Crittski
I would not ride it like that, you will saw through the seat tube quick smart. I think that you should look at a low clamp derailleur instead. It will pull from a lower position on the seat tube and may create a cable angle of pull that doesn't cut your bike in half.

Re: 'Over' bottom bracket cable routing

Posted: Sat Oct 13, 2012 3:39 pm
by GaryF
I think the rear section of the cable guide may have been bent upward at some stage which results in the cable rubbing on the seat tube. I would investigate and perhaps it could be bent downward to its original position if that is the problem. It may need to be re-brazed in place which would require a paint touch up.

Re: 'Over' bottom bracket cable routing

Posted: Sat Oct 13, 2012 3:46 pm
by munga
GaryF wrote:I think the rear section of the cable guide may have been bent upward at some stage which results in the cable rubbing on the seat tube. I would investigate and perhaps it could be bent downward to its original position it that is the problem. It may need to be re-brazed in place which would require a paint touch up.
+1.

you can even see where it's lifted up (probably before the repaint).

Re: 'Over' bottom bracket cable routing

Posted: Sat Oct 13, 2012 7:31 pm
by BRLVR.v2
Yeah thats bent to buggery.

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for reference

Re: 'Over' bottom bracket cable routing

Posted: Sat Oct 13, 2012 7:47 pm
by rkelsen
To get it running, I'd just run the cable under the BB shell. Use a nylon cable guide. They're found on hard rubbish. Otherwise, they can't be more than a few bucks at the shop.

Other options: Bend it back or use a short length of cable housing to protect your frame.

Re: 'Over' bottom bracket cable routing

Posted: Sat Oct 13, 2012 8:51 pm
by Lots of steel bikes
Hmmm, after seeing the guide on the orange frame I realize just how bent it is. I'll try giving it a careful bend. It looks very solid though. Thanks all.

Re: 'Over' bottom bracket cable routing

Posted: Sun Oct 14, 2012 8:39 pm
by Lots of steel bikes
I carefully bent the guide and now all is good. I didn't go too far just in case. There is now a couple of mm between the cable and the tube.
Took it for a run and didn't get far. It has a terrible case of auto shifting even under minimal pressure. Will investigate next weekend.
Apart from dropout adjuster screws, cable end crimps, nicer cranks and an Aliante saddle it's done. Here's a couple of pics. Odd sized unknown makers name frame with 61 ST 56 TT. Suits me just fine.
9 speed Ultegra shifters, brakes and rear D. Shim 600 front D. Suntour dropouts. Nice neat lugwork.

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