A bent frame or fork set is an issue!  An issue, that might well be a "deal breaker", when it comes to restoring a vintage road bicycle.  A "deal breaker", in the sense that the restoration will definitely cost considerably more to implement.  The bent top and down tubes are worth repairing on this very old French Rochet Paris, simply because the bicycle is old.  In most instances, a bent frame would cause me to pass on the purchase.  If I am going to go to the expense and hassle of serious frame work, the final result had better be something pretty special.  And because the Rochet is old, it is pretty special.

A bent tube (or tubes), could well mean tube replacement.  Tube replacement demands heat application, followed by painting and/or re-chroming requirements.  The price for restoration goes up.  One needs to decide if the effort and cost involved is going to be cost effective, for the bicycle at hand.  In the case of this very old French Rochet, the bent frame set is a problem but not a "deal breaker" - for me.  The Rochet, because of its age alone, is worth the extra cost and effort, to repair.  But I might be able to do the repairs myself.  If I had to farm the work out, there is no way that I would take on such a project.  I simply cannot afford to spend large sums of money on an old bicycle.  But what a nice restored bicycle this old Rochet will be when finished.

Generally, I will not sell a frame or fork set that is bent or even suspect of being bent.  If that is the case, why bother with a damaged frame at all?  I have dragged bicycles home that were bent and bent badly!  Why?  Trading material!  I never did build the Rochet even though I fully intended to.  The Rochet was traded, two weeks after I found it, for an incredibly nice top of the line vintage Canadian road bicycle - my 1976 Marinoni Quebec.

All that said, there are some situation that are minor when it comes to bent frame damage.  Most rear ends on vintage road bicycles are bent but ever so slightly.  This situation is not all the difficult to repair.  If you cannot do the work yourself, most local bike shops can do it for you and for very little cost.


The most common bend damage encountered occurs at five locations: the rear drops, the chain/seat stays, the top and down tubes where they meet the head tube lugs, the front forks and finally, the most common of all, the seat post lug.  However, the damage at the seat post lug rarely, if ever, impacts ride quality.

The rear drops have a very tough job to do.  They support well over fifty percent of the load most of the time and are frequently subjected to maintenance issues.  Proper maintenance is not a problem but not all bicycle owners are familiar with proper maintenance procedures.  With frequent removal and installation of the rear wheel, the possibility of damage soars.  These fragile axle attachment points, sooner or later can be knocked out of line with each other.  And this bend problem is extremely common on vintage road bicycles.  Rare does an old road bike that still has parallel drops find its way into The Old Shed.

The rear drops, particularly the pressed steed ones, are frequently misaligned.  They are no longer parallel to one another, as they should be.  Special tools are available to help determine degree of misalignment, and these same tools are used to realign the drops.  A misaligned set of rear drops can negatively impact both ride quality and gear changing opportunity.  This late sixties Italian bike shows typical rear drop misalignment. If you do discover some misalignment, don't get all upset.  With the proper tools and know-how, repair is quite easy. You might even be able to effect repair without the proper tools if you are mechanically inclined and creative.

Closely associated with rear drop misalignment is the spacing of the rear drop-outs.  For most vintage road bikes, the rear drops will be either 120mm or 125mm apart.  If either of these numbers is off, even by a millimetre, then there is the probability of bent chain and seat stays.  Spread or squashed stay spacing is very common and virtually every bicycle needs to be checked for this incredibly common malady.  Dealing with bent stays is not a "deal breaker".  Often times with the simplest of tools, the problem can be rectified and in fairly short order.

Bent main tubes are an issue!  An issue that might well be considered to be a "deal breaker".  The bend usually occurs in both tubes and very close to lugs that join each to the head tube.  If you suspect that the main tubes are bent, back off on the deal.  Unless you really know how to straighten a vintage road bicycle frame set and have the special tools to do so, the task will require the attention of an expert.  The top and down tubes on my 1963 Peugeot PX-10 are bent, as are the fork blades.  Though I am not an expert in this area, I do intend to have a go at repairing the problem.  I have always wanted my French bicycle to be an early PX-10.  If it were not for the rare and collectable nature of this early top of the line Peugeot, the frame set would be in the metal pile at the Dump already.

It is pretty unlikely that the top and down tubes would be bent without the forks experiencing damage also.  Front forks, once again can be straightened out, if not bent too badly.  However, special tools and know how must come into play to effect the repair.  And the repair must be considered carefully.  If too much repair is necessary, the forks might be weakened to the point of being dangerous to use.  Best advice - leave this task to the experts.

The seat tube lug is frequently bent but the problem here will rarely impact ride quality.  The damage to the seat tube lug is usually a product of over tightening the seat post clamp bolt.  The repair is fairly easy to implement and will present little of no danger when the bicycle is being ridden.  That said, if the repair is not done properly, the seat post might slip and create a problem.  Understanding how to install a seat post in a pretty fundamental task that all riders should acquaint themselves with.  And it is not all that difficult to do it right, if you know how.

Those are the five most common points on a frame set to consider when attempting to evaluate a frame set's geometric integrity.  Having this knowledge at hand will make it much easier to see problems immediately, rather than later when the Street Restoration project is completed, only to find that the bicycle will not ride correctly.


When considering a bicycle and attempting to evaluate its geometric integrity, look at the bicycle from a distance.  Eye the bicycle from different angles.  Does anything look bent?  Does the front wheel sit in the middle of the forks?  How about the rear wheel's position?  If you see anything that is even a little bit  suspect, look closer.

An early seventies Mercier looked just fine at first glance and rode all but perfectly.  However, just after test riding the bicycle and while taking pictures of it, I happened to glance at the left fork blade.  It was curved where no curve should be.  The forks were bent.  When I took the time to stand back and have a look, sure enough.  The center line of the fork set did not run parallel to the center line of the head tube.  Further investigation revealed a front wheel that did not sit centered between the fork blades.  How did I manage to miss this major frame deficiency issue?

In all fairness to me, I acquired the Mercier several years ago before I had learned how to properly inspect a vintage road bicycle.  The bicycle had belonged to a lady who said that she rode it rarely and the appearance of the bicycle supported her claim.  The Mercier was nice and shiny.  What could possible be wrong with such a little used bicycle?  As it turned out, plenty!  But I didn't bother to investigate at the time.

If, after observing the bicycle from a distance, you feel that there is cause for concern, look closer.

Look closely at the paint, when looking for “is it bent?”.  The paint at the bend will most likely be cracked and/or even starting to peel.  If you see cracked paint, especially if the rest of the paint is good, look closer at the spot.  You might see a wrinkle in the tubing itself.  WATCH OUT!  If the tubing is wrinkled, you will most likely be taking the frame set to an expert for a very costly repair.

If possible, take the bicycle for a test ride but be very careful!  Test riding can be dangerous!  These days, I do not test ride any bicycle until I have thoroughly inspected it.  However, if a bicycle looks to be reasonably well kept and there is sufficient air in the tires, I will test ride a bicycle without a full inspection.  I do, however, ensure that it is safe to ride.  But I will not go fast…  And a good thing that I don't go fast.

A gorgeous Olmo Grand Prix dumped me on my right shoulder with-in the first five feet of riding the bike.  The Olmo looked to be in excellent condition, except for the inadequately tightened rear axle quick release skewer which I was unaware of at the time.  In my backyard, I mounted the Olmo and pressed on the right pedal.  The rear wheel popped out of the rear drops.  The back end of the bicycle went up.  And over I went, landing hard on my right shoulder.  I hurt for several days after.  Always check a bike over carefully before trusting it!

While test riding a bicycle, I get up a wee bit of speed.  With balance established, I slowly try to remove my hands from the bars.  This does not mean that I throw my hands above my head in a Tour de France victory salute.  It means, one finger tip at a time, I relax my hold on the bars.  I am trying to determine if the bicycle wants to pull one way or the other.  A tendency to pull will become immediately apparent!  The very next thing I do, if "pull" manifests itself, is stop letting go of the bars and get off of the bicycle.  The frame set is likely bent.  Or the forks are bent.  Perhaps both have suffered damage.  The point is, the bicycle is not safe to continue riding.

There are, of course, other ways to determine if a frame set is bent or not.  However, the hands off is definitely the quickest and easiest.  That said, the hands off method is also the most DANGEROUS.  I do not recommend that you actually try it even though I am stupid enough to do so on a regular basis.

Ride the bicycle slowly through a puddle and beyond for a short distance.  Stop, get off and look at the tracks left by the tires.  It there are two sets of tracks, something might be bent.

Or you can hang the bicycle from two thin but strong strings.  Begin by making sure that the wheels are properly mounted and secured in the drops-outs.  Using a single strand for each wheel, hang the bicycle upside-down.  Ensure that the knots on the wheels are in the middle of the rims.  Now look at the bicycle.  Do the wheels remain parallel to each other and to the center-line of the bicycle?  If so, chances are that all is well.  If the front wheel cocks this way or that, repeat the hanging process a few times.  It the wheel persists on cocking, the frame or forks are probably bent.

As mentioned, there is a pretty good chance that any vintage road bicycle found these days will have suffered from a bang or two over the years.  Little bends at certain places are not all that difficult to deal with and most Local Bike Shops should be able to help with repairs.  Some frame issues will create the "deal breaker" situation, unless you really want that particular bicycle.

With dent and bend issues addressed, what else could possible be wrong with an old frame or fork set?  Mother Nature and oxidation (RUST) can certainly be an issue and so can the guy who decided, for whatever reason, to modify his ride.