Replacing rear dropouts

[Flowta]

Recently I got hold of an old frame and built it up into a really nice singlespeed. The only problem is that it has vertical dropouts. I have gotten hold of a half-link and managed to get really good chain tension using the sprockets and stuff I have lying around.

 

It rides really well but it would be nice to be able to have track dropouts on there. It would enable me more options in terms of gear ratio as well as potentially enable me to put a 29er wheel on the back. I currently have a 29er on the front and am very happy with the way it rides. I'm also able to fit a 35c cyclocross wheel/tyre in the back with quite a bit of space.

 

So my question is what would it take to replace the dropouts? They look like they're brazed/sweated in there.

 

Where would I be able to get some?

 

Also thinking making some bolt on type track dropouts, kinda like this guy

http://forums.mtbr.com/showthread.php?t=468451&highlight=socom+29er

 

Is it possible that it would actually work?

 

 

[Flowta]

This what the left dropout looks like.

 

 

[dollar]

I am sure it will work - the brazing may be an issue. I do a fair amount of brazing in my trade, but have not brazed any bikes. It's not generally not difficult.

 

All I can say is that you must have enough heat available and everything needs to fit nice and snug. Its fairly easy to "sweat" things together with braze but its a bit harder to fill. Get someone who has done it before? Let us know how it goes - I would also like to give it a bash

 

[Flowta]

Will do

[Johan Bornman]

The biggest problem will be sourcing the drop-outs. Contact a local framebuilder, even if they don't trade anymore, they may have some. These drop-outs are iron castings and were made by companies like Cinelli, Campagnolo and Reynolds. Framebuilding is still alive in the UK and US, search there.

Brazing them is not an issue. Ideally you need a jig to keep the dropouts (and frame) in exactly the right place until the brazing has solidified. However, you could use a wheel instead. Rig the frame into some rigid fixture, heat the existing drop-outs and remove them.

 

Clean the drop-out receptive area in the frame with a file and make sure the new drop-outs fit nicely. Now, borrow a nice carbon wheel somewhere and fit the new drop-outs to the wheel and insert the whole caboodle into the frame. Do whatever you have to do to get the wheel into position and use clamps, ropes, whatever, to keep it there and keep it rigid. Pay attention to where the tyre sits in the top of the seatstay triangle and at the bottom of the chainstay triangle. Equal gaps everywhere.

 

Braze the new dropouts in with the wheel in position.

 

Remove the wheel, return it to its unfortunate owner, clean and paint the drop-outs and go for a ride.

 

Easier said than done.  Find the new drop-outs and then worry about the details.

 

[Johan Bornman]

Here's a pic of a naked drop-out, albeit not a horizontal one.

 

Perhaps a machine shop can make you one, it's quite simple.

 

[Flowta]

Thanks JB.

 

I'll try get hold of Francois du Toit of Du Toit cycles on Monday. It appears he still does some custom work.

 

If I can't get hold ready made dropouts what material should I get the machine shop to make them out of? Stainless steel? 4130? Would mild steel be ok (I assume not)?

 

I can probably get them made at the University.

 

[Flowta]

Ok, I'm not receiving any email notifications so I'm not sure if it's just me.

 

What materials can I use to make track dropouts?

 

[AndreZA]

Ok' date=' I'm not receiving any email notifications so I'm not sure if it's just me.What materials can I use to make track dropouts?

 

[/quote']

 

 

 

take a nice thick piece of steel and cut it out.

 

 

 

http://www.novacycles.com/catalog/images/COL_DO_FVT_LRG_NEW.jpg

 

 

 

http://www.bikecult.com/works/dropouts/campagPTEth.jpg

 

 

 

http://www.youarefrank.com/blog7/trackdrop.jpgMampara2009-06-22 02:45:30

[Flowta]

That's what I was thinking but what steel?

 

eg Would Mild steel be OK?

 

[AndreZA]

Buy some here

 

 

 

http://www.bikelugs.com/store/index.php?strWebAction=item_detail&intItemID=80

[dollar]

I would go with mild steel - its easier to machine and braze? I am sur you could use EN36B or Stainless but is the nut going to know?