bkbkr

I just got a late model Pista with a suspicious repair to top tube off CL for very cheap. After asking around, I stripped away a bunch of solder and metal tape which I originally had hoped was a welded repair (I'm no expert), to find a clean cut all the way through the top tube. It seems likely the bike was stolen. I've checked stolen bicycle registry to no avail, and I don't think the guy I bought it from is the thief. Not sure how to proceed, but I would like to repair or salvage the bike and am seeking practical advice for this. Is this something that can be repaired? I am not a professional cyclist, I mostly use it to get around my neighborhood and infrequently cycle over the main NYC bridges. I can't really afford a market priced chromoly bike, so it is either repair the Pista or get a heavy ol' beater. I've put up some pictures, hoping someone can steer me towards professional repairs. I have a novice welder pal, but I wanted to ask true bike experts about the feasibility and any recommendable methods.







Thanks!

B

fietsbob

wonder if the Lock was good, so they hacksawed through the frame.. IE Stolen Property.

It could be sleeved inside and then the TIG welding join all 3 pieces together ..
add a outside tube . Tig its ends, for good measure cost for US skilled welding,
is probably same as buying a whole new frame made overseas.

might be chrome plated, then, the chrome would have to be ground away
to reweld to just the bare steel

Airburst

Repairing that isn't a job for a novice welder. It'll be made from such thin-walled tubing that it would take a skilled TIG welder to fix it, and that's if it's not a butted frame (i.e made from tubing that has thicker walls at the ends than in the middle, to save weight). If it is, the tube wall at that point is likely so thing that nobody could weld it, especially not end-to-end like that. Any repair will involve welding some kind of patch over it, and will likely be quite heavy and a potential failure point due to the fact that it'll act as a stress concentration whatever you do.

Bear in mind that the frame basically now hasn't got a top tube as far as structural rigidity goes, so I wouldn't ride it at all, as most of the bending forces on the front triangle (mainly the one that results from your weight) are now being taken by the downtube alone, which doesn't bode well for its long-term fatigue life. It does look like it's got something inside the tubes at the joint, but I don't think it's enough to restore structural integrity to the bike.

A decent used bike of Craigslist doesn't have to be a "heavy ol' beater", many very nice, lightweight bikes can be had on Craigslist for not that much money in most cities.

HillRider

Cut your losses and scrap it.

FBinNY 

You actually have a number of options, from down and dirty to truly sexy.

Before going there, I'm curious. Are there collars on either side of the cut, or is that a trick of lighting.

So here are the choices best first.

Seize the opportunity, and saw the down tube the same way and fit a pair of couplers (or have a frame builder do it for you. This is pricey but you'll end up with a nice come apart bike. Instead of dealing with a patch on problem, it'll be as if you wanted this all along.

Find a piece of thin wall tubing with a 1" ID, or have a a 1-1/6" tube bored to 1". trim the ends as you might a lug, either to a point, ora fancy scroll. Slip it over, center it and braze it in place.

Same tubing concept, but bonded rather than brazed.

Same tubing idea, but split, and clamped with hose clamps at each end.

A key consideration here is cost, vs what the bike is worth, but if you can do the work, or have a local guy who likes crative challenges and works cheap, you can end up OK.

radeln

The deformation at the cut looks like they used a tubing cutter on it. Wouldn't think that would be enough to get a lock out of the frame. Is there another cut?

FBinNY 

Once it's cut, it's easy to get clearance by flexing the long end of the tube sideways.

sreten

Hi,

There are no collars, it is a trick of the lighting.

Wouldn't you have to get the extra tube inside the top to braze it ?
So your brazing steel to steel rather than the presumably outside chrome ?

rgds, sreten.

Kimmo 

Dodgy.

bradtx

bkbkr, Welcome to the forum.

It can be repaired to as strong as new. It will require a collar that is either brazed or tig welded. The collar can have holes drilled into it to provide more area for welding the collar to the tube. Either method will require an experienced craftsman, will cost some money, but less than a replacement frame.

Brad

FBinNY 

The plating would have to be removed in the braze area either way, plus there'd be a heat affected zone where the chrome would be compromised on either side.

If this were mine, I'd make a connector, fitted either inside or outside and bond it, to avoid the issue of heat. Alternately a connector could be fitted inside, and the saw gap is perfect for a weld joining both parts and the sleeve.

Top tube stress isn't that high, and it's compression with a bit of torsion, so the repair needs are fairly light duty for a serviceable city bike.

wphamilton

Would it be crazy to put a pipe inside and use seat collars on both sides of the cut to clamp it down?

HillRider

Assuming the cut is in a suitable location, and I'm not sure it is, fitting S&S Couplers to an existing frame is about a $500 job. Do you really think it's worth it for a CL frame with an unknown but highly suspicious history?

FBinNY 

Probably not, but OTOH, there are builders fitting couplers for less than $500.00, and I only listed it as an option, along with others at the opposite end of the spectrum. I don't make decisions for people, I just try to open eyes to possible options to consider.

No, but collars would work better with a split sleeve on the outside. The problem with collars on an internal sleeve, is that you'd have to slot the frame tubes so the collars could clamp the tubes to the sleeve. Given a choice, I'd rather not slot the frame, so collars and external makes more sense to me.

reddog3

If it were mine I'd strip the chrome two inches on either side of the cut, and do as FB suggested and fashion a fancy sleeve to join the pieces.

I'd make the sleeve 6 inches long- Drill two holes in the bottom to feed some silver. You'd have a good joint with a good bond. Paint the sleeve and polish the bluing out of the chrome. You'd never know it wasn't original.

woodcraft

The finish in the patch area is less scratched, suggesting that the bike was used in it's repaired state for a considerable time.

If that is so, then one of the simpler repair strategies would probably also work OK.