GullyFoylesbike

I got the dream deal last night, found a ratty, but complete / darn near stock '83 720 near me for a song. Picked it up today, only concern is a small dent in the downtube. Ive ridden the hell out of frames with a dented top tube before, and overall this looks very minor, but I wanted to share my find and get peoples opinions on it.


Deerhead RD, Sugino AT, Stronglight A9 headset, original Blackburn rack, cinelli stem, and the suntour bar ends are all keepers.

The dent - no paint cracking, tubes all look nice & straight besides this

Velo Mule

Damn. I don't think it would be a problem, but it would bother me. If it were mine, I'd get blocks and try to roll the dent out. I think it is small enough for this to work.

Wow, nice bike. It's worth a try to roll it out.

SurferRosa

Roll it out, take pics for the next owner, then put another Trek decal there.

polymorphself 

I definitely would roll that out, troublesome or not. It would bother me on such a bike.

sbarner 

This is why I put pipe insulation on most of my bikes when they are not being ridden, though rarely on the down tube. It's not a structural issue, but also not by a lot. It would bother me, too.

gugie 

It's cosmetic. If you roll it out, the paint in that area would probably be worse looking than the dent, and it still won't be completely gone. If you were planning on repainting or powder coating it I'd roll it out then fill it with something like JB Weld, which I've done seveal times. An exception would be if you've got a near perfect match in touch up paint. Semi-gloss black works well for that. Metallic paints are notoriously hard to mach, which is what the OP has.

Ride it, looks small enough not to affect the geometry.

GullyFoylesbike

Ty all for the advice - first step is stripping it down for a cleaning & rebuild, it needs new cables, tape, tubes, and tires anyways. So the question of whether to roll out / deal with the paint damage can wait for now.

I'm interested to see if there are noticable differences between this and my '84 Gitane Grantour, which is made from Vitus 181 and has very similar geo - will probably steal the wheel set from that initially as well. I'll update this as I progress with it.

davester

OMG, that looks serious. Also, you have many more serious problems with that bike. First of all, the splash tape on the handlebars is absolutely passe. Also, what's with the brake levers way down at the bottom of the bar curve. Those need to be moved up. In addition, there are no toe straps attached to the toe clips, a complete disaster. I strongly recommend that you ship this bike immediately to "davester lost cause bike disposal service". After that you'll be able to sleep more soundly at night.

jPrichard10 

I would say the same if it were 25.5".

dddd

Could some sort of "device" be fed up the downtube through the bottom bracket opening?

I'm imagining a piece of tubing, cut in two, about an inch long, with a cone wedge in each end.

Connected to a brake cable housing with a cable attached so as to compress the split tube from both ends, thus expanding it in the vicinity of the dent.

One could feed the device in, slide it up the downtube, apply cable tension to slightly expend the tubing until resistance is felt to sliding the device past the dent.

Once positioned, additional cable tension would wedge apart the tubing, pushing the dent flush with the inside of the tube.

The wedge cones would need a steep enough angle so as to assure their release of expansion when cable tension was released (a stiff compression spring could also be used to push the wedges apart from the split tubing).

Kabuki12

Well, a dent can be a bummer . It helps if you weren’t the one who put it there, yea , it would bother me , until I started pedaling along . You may come up with a way to smooth it out with blocks or something but if you got a good enough deal on the bike ride it . After you take care of the fixable stuff it will be a great bike, enjoy! Joe

Frkl

I've had a similar sort of idea, using a shortened stem quill with the extension removed.

These have enough mechanical advantage to expand steerer tubes, so as long as you could figure out a way to get enough torque on the bolt ... Probably would be a good idea to reinforce the area with blocks to counteract force on the opposite side of the dent. One may not need that much torque, actually, since the force would be very concentrated on the dent.

Would need to be really stubby to get around the corned from the bb shell into the down tube.

But with my luck, it would get stuck in the bike after...

Frkl

Whaddayano? so i might not even have to hacksaw up a stem.

I found them in diameters from 19mm on up. this is actually an expander for attaching stuff to the end of a tube, but in principle it is precisely what you describe above. Some modification would be necessary, of course (that huge washer at the end would obviously need to go, shorter bolt would needed).

So the question is, could it make the turn from the shell to the tube? And how would you turn the bolt? this might do the trick:



of course the only tubes it would work on really are the down tube and seat tube since they have nice openings at the bb shell. In my experience the vent holes at the top tube junctions are just too small. but who knows.

polymorphself 

Let's see the Grantour, that's not a bike we see around here often. Although if you're on Flickr I may already follow you and have seen it.

curbtender

Bought my Miyata 618 from a damaged storage vendor with the same type of dent. I wouldn't fool with it. Nice ride.

GullyFoylesbike

Posted this elsewhere here - truly such a similar build to what the 720 came with. Only difference since this photo was taken was adding a mini front rack & storing the lock up there, as it really does prefer a little weight up front vs in the back. The rear brake bridge was rusted / split when I bought the frame, so I took it to a local framebuilder who replaced that & widened the canti posts as well for more flexibility in brake/rim choices.

sloar 

Good spot for a flick stand.

randyjawa 

If a frame is damaged, in any way (dent, bent, rusted, cracked, etc.) I will buy the bike for the component group only. I don't have any interest in a damaged frame set. That said, as a rider, that dent is a non-issue in my mind. If the price is right and the bike fits, buy it and ride it, ensuring first that it is road worthy and safe to ride.

zandoval 

Ride On Stud... Nice FIND!

The Golden Boy 

Congratulations!!!

Welcome to the 720 club!!!

The Golden Boy 

I dented a frame. I mean, I stowed stuff in the rafters of the garage that happened to work it's way out as the garage door was opened and closed over and over again, and it just happened to fall on my Voyageur SP. It's *just* in my peripheral vision as I'm riding and it always catches my attention. It bothers the living **** out of me.

Trakhak

Similarly, I picture drilling a hole in the center of the dent, installing a steel Nutsert, threading in a long bolt, and pulling out the dent. A hollow wooden cylinder could be shaped to follow the curve of the down tube, with a washer on top for the bolt head to pull against. (Wood, so that it wouldn't mar the finish, one hopes.)

The bike would be left with a Nutsert in a weird location, unless it was drilled out so that it could fall down into the bottom bracket for removal.

Of course, that would then leave a pretty good-sized hole in the down tube that would need to be filled, and might be a structural worry, so the cure might be worse than the disease.

dddd

Using cable and housing to both actuate the device and to act as a handle for getting it into the right spot along the tube, no problem with having to turn any bolt.

As for the vent hole in the seat tube, it could be all but cut away to the full ID of the top tube (using a ball stone on a die grinder, or perhaps a Dremel or a cylinder/head porting tool), allowing some sort of cable-operated device to feed in.
I designed in my head a slim leverage device for this purpose, no cones to wedge, just a pair of brake cable-operated lever arms with mandrels attached, making for entry into a relatively small hole, at an angle, from the seat tube opening.

I have a mint, original, silver-black 1975 Raleigh Pro with a small TT dent, and a 1984 Trek 520 with a bigger dent. Both could be fixed without messing up the paint.

davester

Note that there are many automotive dentless repair vendors who slide their tools into all sorts of difficult to access cavities in cars so that they can massage dents out that look like this. We have had some dents that looked worse than that massaged out in spots that had very tight access. They usually have a very large and varied assortment of massaging tools and some of them have mad skills. You might want to see if one of those guys has some tools that will reach that far.

Frkl

Ah, I see what you mean with the cable and housing. Basically just have a brake lever attached to the end and squeeze hard. Cool idea. something like this:

It would be important that the places where the levers actually push against the tubes not too thin and pointy. I see a problem in that these things need something to push against, and might end up causing a bulge if the area isn't reinforced externally with blocks, or if the contact points are too small. Although any bulge that did happen inadvertently would be a lot easier to fix than the dent that would have just been fixed.

I find myself suddenly in the weird position of wishing I had a frame with a dent in it. I don't think I currently have one.