grizzly907la

I got my hands on a 1985 Cannondale ST 400 road bike frame. It's either a large or extra large frame. I'm going to build it up or I might just repaint the frame. The issue I'm having is with the missing downtube shifters. That's not problem in and of itself. The problem is that I have two threaded holes. I know they sell cable stops that screw into the frame, however I don't which ones I should get. I know it's a stupid question, but I am just getting into this the first time. Any assistance would be appreciated.

Thank you.

The frame itself.

Where the downtube shifters used to be.

fietsbob

Was a shift lever there .. someone stripped it off a creative frame builder may be able to make something to go on there ..

arch stop on the seat stays suggests they took off rear brake posts too .. a Fixie hack Victim?






...

Miele Man

Are the headset cups parallel to each other? The top one looks to be a quite and angle.

Cheers

rccardr 

Not an 85; plastic top tube cable guides mean at least an 86. Check the serial number stamped into the chainstay for manufacture date.
Bracket on seat stays is meant for a rear rack and/or cable stop depending on which model. This is a caliper model, so for a rear rack.
You need a special through-the-frame downtube mount. Hard to find, but you may be able to locate something suitable through a co-op or frame parts supplier.

Ronno6

Your ST500 is at least an '86 but could be as late as 89.
Could be a 27" (68.5cm) frame.
The s/n will tell.....first 2 or 3 digits will be size in inches for the ST frames.
What you are missing are the shifter mounting bosses which were held onto the frame by a threaded fos theu the down tube.

Downtube Shifter Boss / cable stop mounts | Vintage Cannondale Community

Used to be available, but may be hard to find these days,
You can probably get a set of the cable stops which would have attached with screws to the original mounts

Or....just go Dl2 and not worry about cables......
and attach with a long screw and nut or threaded rod w/nuts.

HillRider

That is correct, the downtube shifter mounting bosses were removed or just fell off when the threaded rod failed or unscrewed. You can fasten a pair of Shimano downtube cable stops through the existing holes using a long #10x32 or M5 bolt and nut after drilling out the holes in the cable stops. You will not be able to use downtube shifters after this repair but barend shifters or brifters will work fine.

I made the same repair to a late '80's Klein frame that used the same downtube boss mounting method.

grizzly907la

Thank you for all of the replies! I got an idea of what to do. I don't plan on using downtube shifters. As I said I might repaint the frame and sell, if I don't build it up. The existing holes are threaded and I might use some of these Housing stops to improvise, adapt and overcome. If push comes to shove I can drill out and tap the holes again. At least I have a better idea on how to proceed now. Thanks again!

rccardr 

That simply won’t work. Even if the holes are threaded, the downtube is thin aluminum and won’t securely hold anything.
You might want to try using a piece of threaded rod between two downtube cable stops, but A) I can’t figure out how to properly tighten them, and 2) concave Shimano stops won’t work, you need to use flatties.

HillRider

A) You enlarge the holes in the cable stops to clear a long #10 or M5 bolt and secure the other end with a nut. B) Concave cable stops can become flat cable stops by judicious application of a file or sanding disk.

grizzly907la

Just an update. I'm going to use JBweld and bond some steel braze on cable bosses to the frame. I know its ugly as sin, but I am going to strip the frame, paint and prime it. I'll smooth down the compound before painting and priming it. I might even post pics. Thanks again!

mitchmellow62

This is what I've done in the past. Works fine with the friction thumbies I use. One might need a little more creativity for a cable adjustor if using index shifters.

grizzly907la

I am thinking about using something like this https://www.ebay.com/itm/153750156762 with JBWeld and cover the holes up, so water doesn't seep inside of the frame if I should be riding out in the rain.

Ronno6

This would be perfect if they only made one to fit a tube as large ad a Cannondale downtube.
31.8 ian even close..............

mitchmellow62

You're right. Even though I had a 3.0 back in the 90's I had forgotten how large they are. I doubt there's any clamp ons large enough. My bad.

Crankycrank

No, JB weld isn't strong enough to hold those bosses to the frame for shifter stresses. As mentioned in post #5 from the linked forum thread you'll need this. https://www.cycle-frames.com/NOVA-LE...tegory_id=1068 Instructions are provided on the web page on the correct epoxy and fitting tips. The cable stops in your link will screw into this setup and be plenty strong but may need some sanding to get the inner, concave mounting surface to match the Cannondale sized tubing or go with flat mount cable stops like these. https://www.ebay.com/p/1303432996?ii...kcid=28&chn=ps

rccardr 

Sadly, the item mentioned in the link above to NOVA is out of stock.

grizzly907la

I am not using downtube shifters. I want put the bosses to place cable stops on them. I plan on using either brifters if I go with banana bar or flat bar shifters If I make it into a hybrid bicycle.

It's a shame that nova is out of those boss fittings, because I would rather get those instead.

rccardr 

If you can wait until I get home next week, may be able to cobble something together with actual Cannondale bits that would work with cable stops.
If so, shoot me an e-mail at rccardr@cox.net.

dedhed

Some 8-32 or 6-32 threaded rod, shimano cable stops and, and acorn nuts on the ends.

https://www.homedepot.com/p/Hillman-...0997/202242413
https://www.universalcycles.com/shop...s.php?id=16733
https://www.homedepot.com/p/Everbilt...0251/204274070

grizzly907la

Thanks. I'll check it out!

grizzly907la

I'll check that out! My other issue is that I want to make sure that those holes are properly protected, so water doesn't get inside of them. Call me paranoid, however I want to make sure that the frame is protected, as best as possible.