Lucky Seven seat post with a modern(ish) seat clamp

[RetroSpec]

CABE Members:
I am building a Path Racer Replica of sorts- Is there some way I can use a lucky seven seat post with say-a modern brooks / persons saddle or copy of a brooks / persons saddle single rail ( round) with a modern clamp? is there a shim or way to do this to make it safe/usable? So the lucky 7 is 5/8" and most of these modern bike clamps are 7/8". What can be done to make this work? Alternativley- can I fabricate a "lucky 7" seat post out of 7/8" round stock? Would that be too much weight added to the frame? The attached pic is from a mid 1960's Schwinn Racer. Could I take the inner clamp (5/8" dia) and use it with the outer clamping pieces of a modern post clamp to use with a modern(ish) double or single rail? Any ideas, suggestions or advice would be appricated. Thanks

 

[Chadillac]

Yes I do it. Cut yourself a shim like this.

 

[J-wagon]

Could I take the inner clamp (5/8" dia) and use it with the outer clamping pieces of a modern post clamp to use with a modern(ish) double or single rail?

Yes, I've done this on double rail.

 

[Chadillac]

I had to do the shim because my saddle has three rails. I wanted to keep the original hardware so I didn’t have to pinch the rails.

 

[Archie Sturmer]

Maybe something off-the-shelf.

5/8" to 7/8" x 3" Shaft Adapter Pulley Bore Reducer Bushing Sleeve & Keystock | eBay

Adapts larger wheel bores to smaller axels. Sleeve length is about 3”. Sleeve Keyway slot 3/16”.

www.ebay.com

What I don’t like about some shims, is that they are sometimes just long enough to fit a seat post clamp’s pinching length, making installation or adjustment more challenging.

I would prefer shims that are wider than the clamps by more than 1/4 inch on either side, (but that is just me).

Welcome to the CABE.

 

[J-wagon]

Yes, I've done this on double rail.

I've also done on single rail too

 

[juvela]

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there have been replacement saddles sold in the past which came with an optional shim for for clip

these purpose made shims usually come with little tabs which fold over the top of the clip collar to make mounting and adjustment easier

so this is very much a routine thing


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[RetroSpec]

This is awesome- thanks for the tips, ideas and advice. By far this site ( CABE) is one of the greatest communities of sharing information on the web! I'm happy to be a member. Now if I can only get my bike done before summer is over!

 

[RetroSpec]

To continue with Archie Stumer's post above, I found this ( long split steel spacer) at my local Lowes- So in essence, it would make sense to use a shim such as this one and remove the tab at the perimeter of the interior clamp housing so that I have the adjustablity of using a Luck 7 seat post. Do that sound reasonable?

 

[Archie Sturmer]

The tab might catch the 7/8” OD shim, but not the 5/8” post, (with a little tweaking?);
and sometimes clamps might be found without the tab, (just for a cleaner look).

Also, for seat post clamps like those, I like to add AN960-L ‘thin’ flat washers under the fastening nuts, (5/16 or 3/8, as applicable).