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I scored a cool sierra brown, 1970 Schwinn Tandem 5 speed bike on craigslist (one owner even). I grew up in the 70s and loved the look of this bike, but I guess I had to turn 45 before I got one.

So to my question, my wife wanted a new rear seat, she said the 70s era seat technology is a litte rough on her behind. I put a new rear seat on and slide it as far back on the rails as possible. But when my small, petite wife rides the bike her knees are close to the handlebar. I can't ride on the back now without my knees hitting the handlebar.

I stopped by my local bike shop, and the mechanic pulled out a post that had a nice angle on it. The problem is the diameter of the post, it was larger then the frame could handle.

They said they couldn't get a post in such a small diameter with any type of angle on it.

What options do I have to get the rear seat moved back away from the handelbars?

Any ideas would be appreciated!

Thanks,

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Aww man I'm jealous - can you please add a side-photo of the whole bike?

70's tandems were renouned for being quite short, and most of the length is lost in the stoker's area. Mine's a 80's model and one of the touted features is "2 inches more stoker room!" So if you want the full 70's look, embrace the aero advantage of being so close. And don't eat gas-inducing foods before a ride!

So you've done the first thing, of replacing her saddle. Next is to look for a seat post with a bit more set-back. Make sure you get the right diameter, it could be a 25.4mm pole or a 26.something odd. Use a vernier to measure, and read all over it for an engraved measurement.

Setback seatpost

Handlebar style - I'm not sure what handlebars you have, but it may be possible to rotate them, or replace them. I'm planning on putting some BMX style bars on my tandem for my 12 year old, because he dislikes the dropbars.

You could also replace the bars with cut-down flats. The stoker doesn't (shouldn't!) be trying to steer, so the handlebars are as handles only.

As an aside, your stoker doesn't get to see any of the road ahead, so they get all the bumps without being able to anticipate. So consider a seat post with a bit of built-in suspension. Your stoker will totally appreciate this.

Thudbuster

This style is great, but reasonably pricey. It induces a setback when still and a little more when compressed. Photo is a Cane Creek Thudbuster, but there are many others.

Cheaper

This one doesn't have a name, but its the cheaper tube-in-tube sort. It does take the edge off, but doesn't give you any setback.

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    Hi @Criggie! Thanks for your detailed response. Yesterday we had the misfortune of crashing on the tandem :(. We had helmets so we will heal. The bike is a tank and took no damage! The current seat post is 20.66 mm wide, an odd size for sure. It looks like current bike posts diamater are in the 25mm range. I will continue to hunt around. When I heal up a little more this week I will post pictures. I have it all shiny. I wlll look at different handlebar configuration. Do you know what year they started to add the extra two inches for the stoker?
    – RDotLee
    Apr 5, 2016 at 0:26
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    The built in suspension looks awesome! If I can find the right post, I will be adding that!
    – RDotLee
    Apr 5, 2016 at 0:27
  • 20.66 mm is really small - Wrap a tape around the outside and if your measurement is correct, the circumference would be 65.0mm. On a 25.4mm diameter seatpost, the circumference would be 79.8mm. Is the seatpost made of super-thick steel or something? I'm sorry to hear of your accident - its said that a team needs 500 miles before they're comfortable together on any tandem. There's no specific year for longer stoker areas, it just seems to be a 80s thing.
    – Criggie ♦
    Apr 5, 2016 at 8:17
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The english measure is 13/16" for regular Schwinn seatposts . What may be called a gooseneck post was available to push the seat back 1.5"ish but has a top diameter of 5/8" which was normal then , odd now . Is the seatpost clamped ahead of the bolt under the seat?

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