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Old 08-05-08, 10:14 PM   #1
shriver
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Internally clamping quill seatpost

I'm looking for a longer seat post for my bike. The current one I have is this weird quill that expands inside the frame to fasten it in. The frame itself doesn't have a clamp on it. So far everywhere I've asked has been pretty surprised to see that method used to hold on a seat post, and I've had pretty poor luck finding places I can get a replacement or extension for this *****.

Anyone here ever seen such a thing?
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Old 08-05-08, 10:28 PM   #2
Jeff Wills
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Originally Posted by shriver View Post
I'm looking for a longer seat post for my bike. The current one I have is this weird quill that expands inside the frame to fasten it in. The frame itself doesn't have a clamp on it. So far everywhere I've asked has been pretty surprised to see that method used to hold on a seat post, and I've had pretty poor luck finding places I can get a replacement or extension for this *****.

Anyone here ever seen such a thing?

Yep- there were a couple late '80's Schwinns like this, and some mid-'70's oddball Japanese bikes. You might want to get an accurate measurement of the diameter and then ask on the Vintage list about a replacement. Don't get your hopes up, though.
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Old 08-05-08, 10:49 PM   #3
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Don't get your hopes up, though.
I kinda figured, with the responses I've turned up so far. The bike I have is one of the aforementioned Schwinns, and it's a great bike, as long I don't lose the seat post.
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Old 08-06-08, 02:54 AM   #4
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Originally Posted by shriver View Post
I'm looking for a longer seat post for my bike. The current one I have is this weird quill that expands inside the frame to fasten it in. The frame itself doesn't have a clamp on it. So far everywhere I've asked has been pretty surprised to see that method used to hold on a seat post, and I've had pretty poor luck finding places I can get a replacement or extension for this *****.

Anyone here ever seen such a thing?
Yup, I have one of those weird bikes too. I am extra careful with the seat post because I know that if it is lost or damaged, it will be a real headache to replace.

If you need a fix and the bike isn't collectible, you can use a cutting tool to cut a groove into the rear of the post tube about 2" lengthwise. Then, put a seat clamp collar on the post tube (available at nashbar.com now on sale for $6.99). This approach will also give you a wider variety of seat posts and make seat height adjustment easier.

http://www.nashbar.com/profile.cfm?c...%20Accessories

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Old 08-06-08, 07:03 AM   #5
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Yup, I have one of those weird bikes too. I am extra careful with the seat post because I know that if it is lost or damaged, it will be a real headache to replace.

If you need a fix and the bike isn't collectible, you can use a cutting tool to cut a groove into the rear of the post tube about 2" lengthwise. Then, put a seat clamp collar on the post tube (available at nashbar.com now on sale for $6.99). This approach will also give you a wider variety of seat posts and make seat height adjustment easier.

http://www.nashbar.com/profile.cfm?c...%20Accessories

Good ideas but a couple of further suggestions:

If you cut a slot in the rear of the seat tube, drill a hole (say 1/8" or 3/16" diameter) at the bottom of the slot to prevent the tube from cracking further.

Get a seat tube clamp that has a bolt, not a QR skewer like the one shown. It will be lighter and more secure as your new seatpost and saddle can't be stolen as easily.
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Old 08-06-08, 07:11 AM   #6
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As much as it hurts to cut into a frame, if that's the only option you have, then you may have to. My grandma gave my parents her bike as well as my grandpa's when he passed away, and someone had modified the "girls" bike to lower the seat as low as it could feasibly go by cutting the seat tube off by a significant bit. I assume my grandpa did so that my grandma could feel safer while riding, but I don't know. My mom, while short, is much taller than my grandma, so she needed the seat higher. To accommodate this I pulled out the skill saw and cut a small grove in the back. It still had the clamp for tightening the seat down, but it didn't do anything before. Worked like a charm, and with the seat there no one can even tell without looking for it.
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Old 08-06-08, 07:58 AM   #7
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Originally Posted by HillRider View Post
If you cut a slot in the rear of the seat tube, drill a hole (say 1/8" or 3/16" diameter) at the bottom of the slot to prevent the tube from cracking further.
Just a suggestion: drill the hole before you cut the slot.

I've got an olderish Bianchi ladies bike hanging in the garage with a seatpost like that. I kind of like the look as it gives a very clean uncluttered look to the seattube on the bike. I've been meaning to post a pic of the bike and try to figure out how old it is one of these days, I'll probably do that this week and post it in the C&V section.

Defn: "Olderish": not new, not antique, but age as yet is undetermined.
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Old 08-06-08, 10:08 AM   #8
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Just a suggestion: drill the hole before you cut the slot.
Good catch. I thought about that after I posted and didn't correct it. I'm glad you did.
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Old 08-08-08, 01:53 PM   #9
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Good ideas but a couple of further suggestions:

If you cut a slot in the rear of the seat tube, drill a hole (say 1/8" or 3/16" diameter) at the bottom of the slot to prevent the tube from cracking further.

Get a seat tube clamp that has a bolt, not a QR skewer like the one shown. It will be lighter and more secure as your new seatpost and saddle can't be stolen as easily.
Absolutely great suggestion about drilling the hole at the end of the cut to prevent stress fracturing.

Might even be a better idea to drill the hole and then cut down to it if you have that skill.
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