Bianchi frame cracking

[pigman]

Re:

My mates bianchi split on the headtube as if the headcup had been forced in. He put a jubilee clip on it and carried on for years. Having said that he's not technically minded not fussy what he rides. He's out more for the exercise and camaraderie

Threads on a new frame might not be the same Italian v English threading

 

[Carbonmtb]

I'm not sure what aluminium Bianchi used but they all seem to crack, particularly on the seat tube. Aluminium frames from that era were light and stiff but honestly not as good to ride as steel or more modern carbon. As others have said, time to say goodbye!

Yes my trek madone is a different sort of ride , I believe the mega pro xl are scandium alloy , it has a short back end and feels good out the saddle , more racey geometry than the madone .

Never ridden a steel road bike to be honest .

I’ve had a prove to fix it but the weld will be obvious and will trash the paint . All the other tubes are much thicker than the hydro formed down tube .

 

[MartinB123]

Had a crack on a similar Bianchi around the downtube bosses. Fortunately I bought it like that and used the full Chorus groupset on another bike

 

[Carbonmtb]

Had a crack on a similar Bianchi around the downtube bosses. Fortunately I bought it like that and used the full Chorus groupset on another bike

Ha ha I don’t have much in it so could do the same with the ultegra group set which runs sweet as do the wheels , it’s just what to put it on ..... I have and old frame and forks but the forks aren’t wide enough to take the wheel !

 

[Carbonmtb]

Re:

I’ve spoke to a company Vernon barker cycles that specialise in aluminium repairs , sent some pics over and they said they have seen it before and repaired them , any one any experience of this company ?

 

[danson67]

Vernon's OK. but generally regarded as a bit 'agricultural' in his approach.

Easton's (and Dedacciai's) Sc7000 alloy required a special proprietary alloy filler rod, not just the normal 5356 used on 7005 frames.
Also, does not age naturally like 7005,(as would normally be done after a repair), it requires a different heat cycle post-weld. This from the Easton technical guide:



I do have some of the filler (as I still have a few sets of Easton Sc7000 left and also use Deda Aegis) and the oven to treat correctly, but it's really not worth the work, cost or risk in such a stressed part of the frame.

Bianchi should never have fitted bosses there on the downtube. The walls are probably only 0.7-0.8mm thick in the middle of the tube.
The headtube end butt is plenty thick for welding (2.5-2.7mm wall?) but is only 65mm long on the spec, before mitring, before it starts to taper down, so those bosses will be somewhere on the thinner end of the 120mm long transition ramp to 0.7mm walls...

Say goodbye and retire it.

All the best,

 

[Carbonmtb]

Thank you for that info !

Agricultural doesn’t sound what I’m looking for !!

The group set is mint on it so I guess it can be the prettiest turbo trainer bike until a frame pops up to swap stuff over !

It’s a shame and the rest of the frame is pretty tough , to Hydro form that down tube and make it so thin !!

I think if the bosses had been kept clean behind the corrosion wouldn’t have started ! Oh well !

Will look nice on the wall .

 

[MartinB123]

I'm sure someone in the BOCUK group would take it off your hands!

 

[Carbonmtb]

I'm sure someone in the BOCUK group would take it off your hands!

Possibly! It’s mint in everything other area , with original price tag and proof of purchase and original saddle has been kept in a bag !

 

[greencat]

I agree on Vernon. He's welded a couple of titanium frames for me. It'll be functional, well priced and quick turnaround, but not pretty. It is, of course, no guarantee the frame won't break somewhere else. I had a seat tube crack at the top, got it welded and six months later it cracked at the bottom. Personally, I liked his work as it gave a battle scarred appearance to the bike - but then I have a foot long scar on my torso anyhow.