Wanted Plan To Make Downtube Shifter Boss / cable stop mounts

[Improve Part]

Hi, guys.

I'm a new member, but maybe some people known the new brand in vintage Cannondale community. yes, we are Improve Part team, we produced some vintage parts of Cannondale and hope to supply more parts.

It's appreciate to know Brian who contacted me to join the forums, he told me that in here all of people who into vintage Cannondale too. I focused on MTB parts, didn't realize there are many demand of road bike part too.

Get down to business, we plan to produce some part that many people are looking for, but before producing I need you guys' suggestion of the part, and the data that I cannot measure.

The first data: would you guys help me to measure diameter of frame downtube, I need to make the down side arc of washers fixing frame perfect. I don't know whether there are many kinds of standard in vintage road Cannondale.

The second data: would you guys help me to measure the diameter of hole where the part mounted on.

About the suggestions, I want to know whether you guys prefer to make the shaft with titanium, or still make it with steel? if you have more suggestion, please let me know.

BTW: my English is suck, hope I describe the part correct.

 

[black lightning 1987]

Since the diameter of the down tubes taper it depends on where you measure. I removed the shifter mount assembly from a CAAD2 frame and the down tube measures 41 mm at the mounting hole. Other frames that I measured were in the 44-45 mm range (without removing the shifter mounts). Since there are not many CAAD2 frames out there I would design the part for a 44.5 mm down tube. I can remove the shifter mounts from another frame or two to confirm the measurement.

I measure the large hole in the CAAD2 frame at 6.9 mm but the part that goes in the hole measures 6.4 mm. The small hole that indexes the boss measures 3.5 mm. It appears that you are not planning to have a pin that projects into the small hole on your part. That should work fine with cable stops but it would be nice to have the pin for down tube shifters.

I don't think it would pay to make any of the parts from titanium. The weight savings wouldn't amount to much but titanium would add quite a bit of cost for material and machining.

 

[Improve Part]

Since the diameter of the down tubes taper it depends on where you measure. I removed the shifter mount assembly from a CAAD2 frame and the down tube measures 41 mm at the mounting hole. Other frames that I measured were in the 44-45 mm range (without removing the shifter mounts). Since there are not many CAAD2 frames out there I would design the part for a 44.5 mm down tube. I can remove the shifter mounts from another frame or two to confirm the measurement.

I measure the large hole in the CAAD2 frame at 6.9 mm but the part that goes in the hole measures 6.4 mm. The small hole that indexes the boss measures 3.5 mm. It appears that you are not planning to have a pin that projects into the small hole on your part. That should work fine with cable stops but it would be nice to have the pin for down tube shifters.

I don't think it would pay to make any of the parts from titanium. The weight savings wouldn't amount to much but titanium would add quite a bit of cost for material and machining.

Hi, Thanks for replying. I‘m considering to make some plastic washer that easily be cut to fix more sizes of down tube. about the pin I have to need the accurate data, the part cannot work if the pin cannot be fixed perfect. my English is suck, hope I can describe it correctly.

 

[black lightning 1987]

I think that the plastic washer would work fine when used with STI/Ergopower cable stops. For use with down tube shifters I think it would be a good idea to have the 3 mm indexing pin added. It could be added to the machined aluminum part by drilling and tapping a hole for a 3 mm screw. The original part is only about 2.5 mm thick where the pin needs to be located but you could increase the thickness of the AL platform to achieve whatever is needed to retain the screw.

Let me know if you need more measurements. I have original shifter mounts from most of the series of frames that used them.

 

[CAP57]

Hi new user here, any updates on this project? I am looking to put a modern groupset on a late 80s cannondale frame and am in need of something like this.

 

[black lightning 1987]

Maybe PM Improve Part. Was hoping he would get the parts in production because there aren't many options out there.

 

[Brian]

Improve Part makes great products and is an approved vendor of Vintage Cannondale. I think he can help us with lots of projects.

 

[CAP57]

Maybe PM Improve Part. Was hoping he would get the parts in production because there aren't many options out there.

Thanks just sent him a message!

 

[Brian]

And your thread. :

different types of boss kits?

I found a doner frame and took out the boss kit on the frame however it looks like one side of this boss kit has some extra bumps where my frame only has a single hole for the screw that joins the 2 sides together. The other side fits on the frame nicely. Can I just shave this little node off...

community.vintagecannondale.com

 

[Improve Part]

I know my process so slow, but we're keeping going. today I received the spindle of downtube shifter boss, it's made of titanium, looks nice, right?

Next step, we will make the platform, but I have no data of the small bulges under the platform. would anyone help me to measure it?

 

[black lightning 1987]

Those are there to help prevent the bosses from rotating. They measure about 3 mm in diameter and are located in the center of the concave, approximately 8.75 mm on center from the center of the boss. Height doesn't matter much but it is about 2.5 mm on the original parts.

Looking at your picture it appears that they are located 90 degrees from the center of the concave, so that orientation may vary depending on the year of the frame. I have two originals here, one from the late 1980s and the other from 1997. Both have the 3 mm pins in the center of the concave.