Pogliaghi123

Hello there. I am looking for some help with my 73 colnago super. It’s a gorgeous bike and I’d really like to have it strait. The bend is so minimal it is more for my own personal satisfaction it does not effect the ride. It appears at some point a garage door came down on the handlebars pushing down on the head tube slightly bending the top and bottom tube directly behind the head tube. We are talking millimeters. I actually have taken care of most of the problem by using frame blocks. Clamped on a frame block where the tube is strait and knocked it back towards the bend. I just can’t get directly behind the headtube because of the protruding lugs. I need some help. I don’t care about the paint. I don’t want it restored. I just want the angles it would have had. Thank you for the help

dsaul

That sort of damage is typically caused by a significant frontal impact. It's not likely that a garage door coming down on the bars would cause that type of damage. It will probably never be straight again without replacing the top and down tubes. I'd just ride it as is.

Pogliaghi123

I’ve spoke with the guys at cicli in Italy and they say it can be easily fixed without replacing the tubes. I just don’t want to ship overseas with the way things are at the moment. Would like input from some USA frame builders

Pogliaghi123

there’s a sort of crimping that happens during front end collisions that I do not see here. I do not believe it was a front end collision

Andrew R Stewart 

Tube bending (as from a frontal impact) has differing amounts of crimping or deformations dependent on a few factors. The lack of ripples don't mean no HT angle shift happened. Andy

Pogliaghi123

(Dr. Evil voice) Riiiiiggghhhttttt
Well let’s have a look at some more creative ideas that doesn’t involve replacing the tubes

guy153

Well I guess a start might be to measure what the HT angle currently is to see if it has moved. You probably don't know what it was supposed to be to start with but if it's somewhere between 71 and 74 degrees that should be fine. If it's in the right range and not twisted then just fill the dents with car body filler and job's a good 'un.

Pogliaghi123

i do have the specs for a 73 colnago super and I have another super from the same year in the exact same size for comparison. I have made crude comparative measurements for myself as stated before we are talking millimeters.

unterhausen

Might as well ask in C&V, because that's where I see all the hack approaches to this kind of repair. I don't know if tube rolling will fix it. I think a framebuilder will tell you to replace the tubes or GTFO. Or send it to Italy, but they probably use bondo if they think it's easy.

If a garage door did this, it either fell unhindered or it really needs to be adjusted. And even then, I don't see how the bike could have been sitting on the ground in normal riding position and sustaining this damage. Maybe it was doing wheelies.

Pogliaghi123

yes maybe I have posted in the wrong place

Pogliaghi123

out of curiosity, why would bondo be used here? There’s no dents

'02 nrs

if you have a frame for comparison try using the angle finder app.https://play.google.com/store/apps/d...hl=en_US&gl=US

unterhausen

maybe I'm looking at the picture wrong, and it's not the best picture, but it sure looks like there are places where the tube is pushed in to me. I don't see how a buckled tube only sticks out, but if it does then you should be able to roll them successfully with tube blocks. I am theorizing that any "easy" repair involves a combination of tube block rolling and bondo. I am also suggesting that it might not be a fully satisfactory repair. I suggest consulting with an experienced painter if that kind of repair would meet your needs.

Sonofamechanic 

The angle measures are a better place to start if you don’t know exactly how the damage was done (per your original post). I recently straightened a frame with the same appearance of damage but an angle check revealed the whole front triangle was significantly out of kilter—best we can assess is the frame was mounted on a roof rack, locked in at the fork ends, and driven into a garage. Frame pivoted on the fork ends and the head tube went down by pivoting on the lugs with minimal visual impact to tubes (some wrinkles). In this case we mounted the head tube running a solid bar up through it (with steel end caps/races to help minimize deformity), locked the bar into a vice at approx length of fork, and then used a chain “come-along” (coffin hoist is the old term) attached (with cross pipe) to bb and to the base of workbench leg to pull down and in (at the same time) on the frame—-this let the “triangle*” straighten out. (*Technically its an irregular quadrilateral so the angles can change without bending/compressing the sides.).


Pink is prior to straightening (lengths are not to scale)

Pink is before straightening—shows direction of pull—head tube was held stable.

Pogliaghi123

The tubes are not pushed in and there are no dents. I have used frame blocks to take care of just about everything but directly behind the headtube as the protruding lug keep the frame blocks from going that high. As stated before

Pogliaghi123

YES!! this is the process I was thinking about attempting and it sounds like we have the exact same problem. I hear there is a discontinued park tool for this very purpose. Could you provide some before and after pics if you have them? I definitely want to talk to you about this more. I wanted to see if a frame builder could help me before taking this step first and as to be expected at this particular forum I was immediately told to replace the tubes. There’s only one solution to a lot of these guys. Thank you for your help

Andrew R Stewart 

There have been several HT "straightening" bike tools over the years. They all share the contact points of the BB and the HT's inside. They all try to push the lower HT away from the BB. Some use a big screw thread, others have used rack and pawl (car jack). Some use the OEM fork and an axle (and can bend that fork too...) others a big diameter bar running up through the HT. All can do significant work! Some tube damage can happen with clumsy use. The Park HTS-1 in my basement has been used 1 time in the last 10ish years. There was a time when we needed it a couple of times a month.

"I wanted to see if a frame builder could help me before taking this step first and as to be expected at this particular forum I was immediately told to replace the tubes. There’s only one solution to a lot of these guys." P123
Well different skill sets will see different solutions that they can do, hopefully do well with no secondary issues that can develop (like) when bending things, Andy

unterhausen

As a rider and a framebulder, there is no way I would happily ride this frame if it was just straightened. Other people have different risk tolerance. It's simply not possible to fully un-buckle a lightweight tube.

I never tried the Park frame straightener on a bike with thin tubing. People in C&V have said that it works a lot better on thin tubing and I believe them. I have tried it on cheap bikes and it's hard to get it to do anything at all. BB shells and head tubes will bend too, BTDT. I am not sure how it straightens a top tube though. Seems like you would need to mount the frame by the bb and seat tube and stretch it back by pulling on the head tube. The tool is really meant to fix issues where the force on the frame came through the front dropouts. It reverses the levering action that the frame previously saw from a strike to the front wheel. Of course, all the garage strikes I have seen were just like what happens when riding into a parked car, which is probably why this frame looks like it was ridden into a parked car.

I suggest that if it's important to you that you send pictures to Franklin Frames and ask what it would cost to have them fix it. If there is an easy fix, it will be cheaper than sending it to Italy, and they do good work. They might even replace the tubes for a reasonable price, but you can't know until you ask.

Pogliaghi123

very good advice and it does mean a lot to me. It’s not something I’m going to go in trying to fix not knowing what I’m doing or trying something for the first time. I will look into Franklins. Thank you for your comment and time

unterhausen

I think if there is such a thing as a "grail bike" for me, it would be an early '70s Colnago. Okay, it's really just the right Eisentraut, but I feel like I have a better chance of finding the Colnago.

Sonofamechanic 

I love this forum!...a fellow bike owner asks a pretty straightforward question and well over half of the responses either answer a different question or second guess the original one!! . (Not pointing fingers...I’ve done it too).

Sonofamechanic 

Pogliaghi123–the comments below are assuming you go the route of fixing this yourself:
Definitely first checking the angles will greatly help you decide how to best fix it. If its a “frontal collision” type accident the angles in the front “triangle” may all be mostly correct but the tubes will have compressed slightly (typically you see this more on cheap tubing or NJS track bike tubing, not on your Colnago-grade tubing)—if this is the case then un-wrinkle a few tube bubbles if you must but otherwise you could opt to ride it (as is as long as you have sufficient down tube to front wheel clearance.) If the top tube to seat tube angle is correct but the head tube angles are not (typical “I hit a pothole/car door” bend) then the Park tool (or a home-made equivalent using a pole jack) is exactly the tool you need and it will mostly fix the problem...but this specific type of damage is easily replicated when you hit the next pothole, or curb, or even by slamming on the front brakes and your already bent/repaired frame will undoubtedly have less than the original “resilience” to being re-damaged in that same way (that is where the “new tubes” option comes in). However, if the damage is from above, as you are guessing is the case for your frame and as was the case in the one I drew out above, the 4 angles in the front “triangle” will all be off and result in some variation of the drawings i posted above. If that is what has happened then the fix is easier and will not be as great a future liability as that type of stress/accident is not replicated in any way under normal riding conditions. Its hard for us bike-folks to wrap our head around that because we don’t often see this type of damage.

Pogliaghi123

My God...Thank you sir. I absolutely love vintage bikes and I collect vintage BMX too. Have two little boys I collect with. And I have some really rare birds. I deeply appreciate them and the craftsmanship. If I post a question it’s always an honest one with no ill intent. I have always thought this about the forum. There’s just so many bike snobs or just grumpy old farts I don’t know what the deal is.

Sonofamechanic 

Oh I’m definitely with all the grumpy old types as well but I get all my angst out complaining about how bad other people drive so I can stay positive for the biking brotherhood. .
Let us know what your angles come out as and we’ll all pool our experience to get you to a DIY solution and leave the “risk factoring” to you.

63rickert

Franklin Frames is very good.

Also possible is Andy Muzi/Yellow Jersey. His webpages are old and a mess, if you take a good look around you will find lots of repaired frames that look impossible yet turned out looking fresh. A practice makes perfect situation, when still in Madison they straightened literally thousands of commuter bikes no one else would have attempted. And then the nice bike comes in and they know what to do.

Either Franklin or Yellow Jersey should be able to give a quick appraisal from those photos.

My Cinelli was far worse than that, really far worse, Ron Boi brought it back for another 100,000 miles. He is sadly no longer available.

The wife rides a ‘73 Colnago Super. They were very special bikes. This job is worth the trouble.