capnjonny 

I am finishing the assembly on a 1972 Botteccia Special I have been restoring for the Bike Exchange and after trial fitting the beautiful Nervar crank I noticed that the chain rings wobble about 2 mm side to side.

Closer inspection indicates that one of the 3 spider arms is slightly bent. I am going to try to bend it back and am looking for advice on how to do it.

Has anyone had this problem before and if so how did you fix it.

Thanks, I will post pics when finished.

Cap'n Jonny

3alarmer 

Andrew R Stewart 

Crank arm spiders and rings are needing straightening frequently enough. All kinds of pry tools can be used, Large screwdrivers, pedal wrenches, hammers, adjustable wrenches are all pretty common methods. Bicycle Research (and others they likely copied from) made a special tool for bending rings.

Using two of these tools (or two adjustable wrenches with a screwdriver run through the wrenches' end hole for added leverage, placed on either side of a warp portion of a ring (where the wobble is not influenced by the spider arm) and levered in or out will bulge the ring this way or that way. Much like truing a rotor with a couple of disk forks.

Back in the day of steel cottered cranks we had to do this stuff on nearly all assemblies to one degree or another. Once straightened the rings tended to stay that way better then modern stamped (as in low cost) steel tings of today do. One reason is that with no specific shift gates or lift pins the rings didn't have the focus of forces on just a small portion of the ring. Also non shift enhanced rings required the rider to learn how to ease off the pedal pressures when shifting, a technique that still is a good method but seems to have been somewhat lost on many of today's riders Andy

dsbrantjr

A large box end wrench padded with leather might make an effective lever to nudge the spider arm back into line. Assuming a steel frame you could use a dial indicator on a magnetic base to monitor your progress.

Jeff Wills

As Andy noted, this was quite common back in the day. 2 millimeters isn't much- we would probably only "fix" it if the customer mentioned it. Ride the bike... if you can't trim out the front derailleur while riding then address the issue.

capnjonny 

I decided to try to fix the problem today . First, I found a couple of thin washers and slipped them between the spider and the rings. This didn't have an appreciable effect so I took the rings off and clamped the spider in my wood working vise( wood jaws) then using a large Jorgeson clamp, I carefully bent the arm . It bent enough on the second nudge that I called it good and bolted everything back together. Now the run out is about half what it was.

I am getting excited with the progress on the 1972 Botteccia. I found a crank spindle that fits and is un pitted and was anxious to get it installed. I had it dry fit while I was swapping out spindles and fixing the crank., then filing a new set of Cotters. With every thing finally dialed in I lubed up the bearings and assembled everything. Now all that's left is the cabling for the front and rear derailleurs.

One small mystery. this frame has no cable guide on the drive side at the bottom bracket. The non drive side has a cable stop at the bottom of the down tube , but the other side has nothing. I have looked at other Botteccia frames and they all have the guide for the rear derailleur cable. I have a bolt on Campi guide but it has cable guides on both sides so won't work. I have other guides but wanted to use the Campi. I know this bike isn't catalog perfect but it is close. It is at least era appropriate mostly.

No name aluminum bars with TTT open back stem
Weinman levers with hoods
Universal model 62 center pull brakes
Nervar cotter ed crank w/ 39/52 tooth rings
Campi down tube shifters
Campi piston style front derailleur
Campi Valentino rear derailleur
Campi small flange hubs
Rigida red lable narrow rims
Schwalb 700 x 25 Tires

capnjonny 

Drum Roll -------

And now , the 1972 Botteccia Special , with selected mods and upgrades.








And here is a donor frame giving up its mint head badge




I was even able to save and re use the spiral shank rivets!

One last minute hassle, when everything was complete and I had taken pictures I discovered that the stem was loose and I couldn't tighten it . This required removing the bar tape from one side, pulling the lever, then pulling the TTT stem and replacing it with an even nicer AVA (with closed back). Oh well.

Now on to the French mystery bike.