funbuffalo24

Hey guys, I've got a mid eighties Bianchi Sport SX frame and a complete Shimano 105 groupset I'd like to put on it. I'm aware I need to cold set the current dropout spacing from the current 126 mm(124.5 as measured) out to 130 mm, readjust the dropouts, install down tube cable stops etc. My question though is this, there's two cable guides brazed onto the top of the bottom bracket... can I/should I use those to route new derailleur cables, or should I drill and tap the BB shell and run them underneath through a plastic cable guide? My biggest concern is that id be putting a new guide directly through the SN on the bottom of the BB.

On a second note, the square taper spindle it had originally would be replaced with a hollowtech style English thread one, would it be in my best interest to reface the BB, or leave well enough alone?

rccardr 

Over the BB cable routing works fine for STI, no need to change it. I would use a short section of cable liner there to minimize friction, but that's just me.
Use the new style BB with your newer crankset, it will work fine.

alcjphil

The bottom bracket type you use has to fit the crank. A square taper crank will not fit a Hollowtech bottom bracket of any description

funbuffalo24

Yeah I understand that, perhaps I should have clarified. The only thing I really intend to reuse on the bike is the frame itself, and possibly the quill stem and handlebar. I have a new crank new set of wheels brakes Etc

Litespud

won't the Bianchi have an ITA-threaded BB shell? If so, the English-threaded BB won't work

Homebrew01

I use a quill adapter on my old steel bike, with a modern stem. Doesn't have the same "look", but easier to swap stems if needed.

Use the existing cable guides.

fietsbob

Just there is a need for the RD cage lower tip to not snag on the cable
as it passes over the BB, on its way back to the RD..

On my bike that means a 52t chainring..

same crank & FD, on my under the BB cable route, bike frame, I have a 50 t big ring..

fietsbob

Bianchi USA has been getting pac rim factory made frames on their bikes
for over 2 decades..
so it's then not Italian.. but in name...

funbuffalo24

Correct, this is a Japanese built frame using Tange chromoly 'superset' tubing and has a "Made in Japan" sticker just above the BB on the seat tube. The BB has an overall outside width of 68.1mm, ID of 33.7mm, OD of 39.4mm, and lastly the outer cup is marked 1.37x24T, so I was mostly confident that this was an english thread. Thanks for the help folks, once I find the time to build this up I'll give an update.

jlaw

You mention needing to cold-set the frame to go from 124.5 to 130mm. Before you bother doing that (and potentially creating other issues) you might want to try simply spreading the stays by hand to insert the new 130mm rear hub.

I have a mid-80's Trek that measured 126mm originally and I was able to get a 130mm hub into the frame by hand without a problem.

fietsbob

one thing.
simply spreading the chain/seatstays,
the dropouts will not be parallel any more..

once the wheel is in, at least check the derailleur hanger alignment
(with shop tool)

jlaw

Good point - after I got the bike together (the mid-80's Trek previously mentioned) I couldn't get the index shifting the adjust properly. I took it to my LBS and they put their alignment tool on it and found the RD hanger was significantly out of whack. A little tweaking and all was well.


However, I think the RD hanger had been bent by impact whereas the spreading of the frame by 4mm to fit the 130mm hub didn't account for much - but I can't be certain.

funbuffalo24

thanks for the reminder, I do have a Park derailleur alignment tool, drop alignment set, as well as the frame alignment gauge and their straightening tool. This is exactly why I have steel frames.

On a secondary note, my 1" headset is worn enough to where I'd like to replace it now too, the bearings are far too gone and the races are ok, but they could use a refresh. Any recommendations? The bay has a bunch of old OEM stuff, as well as ritchey and a few others. Dunno if I'm ready to cough up Chris king money just yet on a cheap(er) old bike I plan on using for my rainy day/all around backup.

Thanks again for all the help guys, it's been close to a decade since I really biked much or even wrenched on my bikes, it's good to get back in the saddle again literally and figuratively.

jlaw

[QUOTE=funbuffalo24;20598662]thanks for the reminder, I do have a Park derailleur alignment tool, drop alignment set, as well as the frame alignment gauge and their straightening tool. This is exactly why I have steel frames.



Wow! With those kind of advanced bike tools I'm not sure why I'M giving YOU advice!

funbuffalo24

Hahaha, no worries man. Back in the day when I was young, had a lot of time and a lot of fun money available to me, I didn't take the advice from the movie Tropic Thunder and I went 'full ******' when buying all possible bike maintenance tools for my bikes(don't even ask me about my spare truing stand I bought a few weeks ago though). Flash forward to now and I hemmed and hawed for almost a month before pulling the trigger on a new rear gearset for my backup rims.

Andrew R Stewart 

funb24- I'm only an hour away in Rottenchester, in case you want help with your frame work. Andy