Rear Rack Mounting

[Vetteman61]

I'm looking to put a rear mount on a 1964 Space Frame bike (1964 Foremost). I've noticed that the rear seat clamp uses a carriage bolt and that the original racks mounted to this bolt. I've looked online and seen that the original racks just have a round hole here, but I don't understand how a rack mounts to the bolt and does not interfere with the carriage bolt going through the bike to hold itself in place.

would anyone have some close up pictures on how this works?

thanks,
Brandon

 

[Vetteman61]

Anyone?

 

[AndyA]

I'm away from home so I can't check this right now, but I think that my Flightliner has a carriage bolt on the seat clamp.The rack support has a round hole but the seat clamp has a square hole. Maybe the square shank of the carriage bolt is long enough to extend into the clamp. When I get home, I'll take a look and confirm (or not).

 

[Roger Henning]

The seat post clamp has holes on both sides for the bolt to go through. One is square to hold the the bolt from turning and the other side is round for the threaded part of the bolt to go through. Tighten with a nut. I have had a bike(s) with this system all were low end K Mart quality bikes. Roger

 

[Rivnut]

I have some Murray made bikes with the "carriage" bolt in the seatvtubevclamp. Just take a small triangle shaped file and open up the hole in the rack to match the hole in the clamp.

 

[Vetteman61]

Thank you for the reponses. I'm curious, did any of the bike with the carriage bolts come with a rear rack?

 

[AndyA]

Oops, memory failure. Flightliner (red bike below) has a hex bolt thru the rack support and seat clamp. Same arrangement on a Spaceliner (silver bike). I can't say for sure that this is the original setup. They work fine; the only drawback is that adjustment requires two wrenches.

 

[Sven]

This is what's on my '59 Flightliner , a carriage bolt

 

[AndyA]

Uncle Sven:
Does the square shoulder on the bolt fit into a square hole in the seat clamp?

 

[Rivnut]

These are racks that are on "in process" bikes - ones that I did not have to disassemble to photograph

Prewar Elgin - one of two but I only took one picture. Came as part of the original bike, not added-on.

Post war JC Higgins. Againg, part of the bike as it came from the factory

These line up with the carriage bolt square hole in the seat post bracket.
I looked at a Schwinn wire rack and it has the same hole in the rack as in the seat post clamp. A hole with a couple of reliefs at 3 and 9 o'clock where ears on the AS bolt lock in and keep the bolt from turning as you tighten the nut. Hope this helps.

Ed