Re-routing 49cm '04 Bianchi Axis rear brake
While awaiting the arrival of my new '04 Bianchi Axis, I went to my LBS to take care of something on another bike and took a gander at the 44cm they had in stock. On these frames (44 and 49cm only) it's my understanding that instead of welding a cable stop to the seatstay bridge for the rear brake cable, they instead route the rear brake cable through a cable guide that is attached to the seatpost. It looks like this cable guide is removable. On the top tube the deralleur cables look they're routed the same as the larger frames, although there appears to be one empty cable stop near the seatpost on the top-tube, which would normally be used for the rear brake on the larger frame sizes (52cm and above). I'm wondering if I can use a bracket, such as DiaCompe BR1235, which mounts to the center of the seat-binder bolt, instead of this seatpost cable guide. This way I'd be able to route the rear brake cable more like the larger frames and use that third cable stop on the seat tube. Anyone else have experience with this? Would this help avoid the rear brake from pulling to one side, etc...? Also, does anyone know if the 49cm Axis sports the same seatpost pulley system for the front derailleur as the larger frames?
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My 49cm '04 Axis rear brake doesn't pull to one side. You may have to play with the spring tension on the cantis (the little screw on the side of the canti arms).
The front derailer on the 49cm frame also uses the pulley to convert a top-routed cable to use a bottom pull front derailer.
My girl friend's 49cm 2003 Axis came with two dificiencies which I can share info about:
o Rear brake cable routing (2003/2004 frameset)
The rear brake routing is horrible for the smaller sizes (49cm and smaller, 44cm?). I believe the same is true for 2004 frames. Bianchi opted to use a nylon sleeved cable guide which attaches to the side of the seat tube (just below the seat post binder); instead of the usual cables stop on the seat stays and top tube. Note: the third top tube cable stop at the seat post is also missing. Most likely Bianchi chose this option due to the limited space for straddle wire clearance on the smaller frames. Anyways, since the cable guide is offset to one side, the brake calipers have uneven pull. You can offset the caliper tension to compensate for this somewhat, but the package in it's entirety is still klugey.
What we've done is installed a seat binder cable stop, and ran the external housing all the way through to the brake levers. The housing is held down to the top tube with disk brake cable hold downs (self adhesive style). For a long term solution we plan to rivet a cable stop to the top tube. Yes, this means drilling the frame, etc. Then we can route the brake cable as originally intended (something Bianchi should have done). Note: Bianchi should at least have included the third cable stop, regardless of whether they used it or not. Shallow thinking. On the other hand we don't understand why they chose the option they did, as we've not found any issue with straddle wire clearance. It's a little tighter than with the larger frames, but mostly adequate.
o Front derailleur cable routing (2003 frameset only)
The 2003 frame used a mountain bike front derailleur with a double crankset. Even though a mountain triple front derailleur requires more cable pull than a road, the Shimano 105 shifters had no problems moving the stock Shimano LX (mountain triple derailleur) to span two chainrings. However the LX derailleur would not span triple rings when used with the 105 levers (mountain derailleurs get more cable pull via flat bar shifters).
So when we wanted to convert to a triple crankset we needed to use a triple road derailleur to match the cable pull of the 105 levers. Since road derailleurs are usually bottom pull, and the front derailleur cable routing was top pull, we needed to add a conversion pulley. This unit mounts at the bottom of the seat tube and wraps the cable back up to the front derailleur. The unit costs about $20 - $25. Bianchi Axis 2004's are configured with triple cranks, therefore already come with a road derailleur (Shimano 105) and a conversion pulley mounted to the frame.
Last edited by dessert1st; 09-27-04 at 02:34 PM.
Thanks for the detailed reply! I asked my LBS about this and of course they were completely clueless and looked at me like I was crazy... They also couldn't find an '04 Axis in my size so now I'm waiting for my '05 to come in. I've been mulling over this and had been thinking exactly along those same lines - I have already purchased the seat-binder cable hanger. I just wasn't sure how to get the cable back there. Ideally, I'd like to find a seat-tube mounted cable stop, which would function just like a third top-tube mounted cable stop, except back a little farther. This way I'd have the three cables running along the top tube, as nature intended. I haven't had any luck finding such a part however (although I did see one on someone's old bike parked on the street the other day), even on loosescrews.com. They do have clamp-style top-tube mounted cable stops, but of course the top tube of the Axis ain't round back near the seat tube. After I get the bike I'll be able to figure out if I could use one of these, mouted maybe half-way back towards the seat tube, where it's still round. Then I'd run cable housing from there to the cable hanger, then to the breaks. Or, if/when I switch to linear-pull brakes I'd run housing from the cable stop directly to the brakes (via a Travel Agent brake pulley, of course). I'm not totally averse to riveting a cable stop into my frame as well...
I'm pretty sure the clamp style cable stop won't work because the Bianchi's top tube just isn't round enough. The V-brake option is a good idea as that eliminates the cable stop need, but you still need to hold the cable housing down (tie wrap will work or a self-adhesive hydraulic line hold-down). From what I've read using travel agents may be tricky as they put a lot of stress on the cable (due to the sharp bend). Using higher quality cables such as Dura-Ace can help. Dura-Ace cables have finer strands.
Originally Posted by SAB
If you're interested in one of the rivet style cable stops, I can mail you one (I bought an extra). They're inexpensive, wound up costing about $4 each after shipping/handling. The cable stop requires a little bit of filing on the bottom to flatten it and fit the flat contour of the top tube better (it's designed for round tubes). It's also an alloy silver color but it can be painted. We haven't figured out how to rivet it on yet, have to consult with the local frame builder. My direct email address is email@example.com for more info.
Last edited by dessert1st; 09-27-04 at 02:35 PM.