What is with this seatpost?
 

Hi: Just picked up my first road bike, sold without seat. Figured i could swap a saddle a/o seatpost off my MTB or hybrid, but it looks to be of marginally smaller diameter-- other seatposts I have won't fit in-- and the top is not clamp style, so I can't just attach saddles I have to it. The post says SR on it. Bike is a Univega Viva Sport ($20!!!-- post in Univega appreciation thread to follow).

http://bikeforums.net/attachment.php...hmentid=253516.

Does the post just need hardware for a seat with two rails underneath to attach to, and if so, can anyone tell me what that hardware is / where to find?

Or is this style post for some particular kind of seat that I would need?

Any info on it appreciated. Thanks.

Yes that post is missing all the hardware to attach a seat. Your better off just getting a new one. Does that one come out?

the hardware you are looking for can be found at a bike shop for a few bucks . just take the post to the shop with you and the staff will know what you need .

looks like the hardware from this should work http://www.amazon.com/Saddle-Clamp-P.../dp/B000AOA0T2

#1,is the seat post frozen in the frame?. or can it be moved , take it out an apply some grease so it will not freeze-up in the near future'


the teeth on those wear down and the saddle will slip.. angle insecure..

No, not at all!! That clamp requires a straight seatpost necked down on top to take the circular clamp. Just using the outer cups and bolt won't provide the inner rail clips. He can either find the missing pieces at a bike shop if he's lucky or buy a complete new Kalloy seatpost for not much money.

To the OP: The proper diameter for the replacement seatpost can be found by removing the current one and reading the diameter engraved at its lower end.

Actually this is sort of a hybrid seatpost. It uses the same clamp hardware as clamp-on saddle brackets, but not the center section which is integrated into the post. If the OP buys a decent saddle bracket and chucks the center section, he can make this work. It won't be perfect because the serrations wont match, but it will work decently enough if he doesn't change the saddle position often.

OK, maybe it will work but it seems it will clamp only the outside of the saddle rails. Perhaps that's enough. I still think a replacement post is worth the slight extra cost.

yea i was thinking of chucking the center section and using the outside bits

It clamps both sides of each rail. It works exactly like a standard saddle bracket. The only part that's different is the innermost U-bracket that would slip over the top of a pin type seat post. If you look at the photo, you'll see the post even has the square hole which keeps the bolt from rotating.

I think you are right but it is hard to tell from the pic if the top of that post is as wide as a standard saddle clamp. Looks a bit narrower (which could be an issue) but can't really tell from the angle the picture is taken at.

Thanks all. I was having trouble visualizing how the linked part would attach.

Can't get to more photos or measurements until tomorrow.

Problem is, I can't 'order' anything. This is my new-to-me, first ever in my life steel road bike, all ready to go except for the minor issue of having no seat. I need to go for a ride ASAP!

Checked one local shop for the hardware tonight and they did not have it, but did have a replacement seat post for $21-- 105% of the cost of the bike!

Will check the other 3 shops tomorrow and if I can't get the hardware locally, will just have to spring for a new post.

Thanks again, will report back on the outcome.

Yeah, that clamp reptilezs showed you only works on straight-tube posts.

Rest assured, the $21 post this shop showed you is a pretty direct replacement for the incomplete one you have on the bike.

I've cannibalized clamp parts for that style seat post many times from an old style round seat post clamp.

The OP's seat post was pretty common in the 1970s, I have had about ten Nishikis from the 1970s with that style post. All were on road/racing bikes.

At the same time, those posts were on the crappy side, and hefty, I would go with a newer style alloy post, with a traditional rail clamp. $21 at your LBS is about right. Want something cheaper? Measure your post, and head to the nearest co-op.

I've used MANY of those clamps reptilezs linked from Amazon on orphaned seatposts. Here's how you use it with the OP's partial seatpost:

1. order Amazon seat-clamp, or scavenge it from bike-shop's junk pile. Or local college student self-serv bike-shop.

2. unscrew two nuts from both sides

3. remove two cupped washers from each side (4 total)

4. slide out clamp part in middle and toss (keep the bolt).

5. slide square bolt through seatpost top

6. slide on larger of cupped clamp washers on each side

7. install seat, rotate clamp washer to hold rails

8. slide on smaller clamp washers, rotate so clamp goes over seat-rails

9. install nuts on each side, rotate/slide seat to proper position

10. tighten nuts.

Just in case my how-to steps doesn't explain it in abstract enough concepts. The Amazon clamp (and all Wald-type seat-clamps) uses two cupped washers per side. These washers have sections that holds onto the inside and outside of each seat-rail. The only thing we're tossing is the centre section that goes over a straight seatpost.

[edited to remove snarky comment... sorry!]

It doesn't matter what your original bike cost, $21 is cheap, even more so (in spades) when you " need to go for a ride ASAP!" You'd be riding now instead of making another post!

Don't get me wrong - I love to make things work, save money, not throw stuff away, and spend way too much time cruising used, cast out parts, specialty hardware/fastener stores, etc. etc. But $21, available immediately, riding immediately vs. spending another hour or a few days looking for a $5-10 alternative, to save $10 net .... come on!

better to just buy a plain seatpost made to accept the clamp shown in #4..

those old posts shed aluminum and the teeth went away.
at least using the whole saddle clip, the teeth are both steel,
and match.

I hate to break this to you but the fact that you bought the bike for $20 doesn't automatically lower the cost of whatever parts it needs. :)

Yeah, I know. But it's a 30 yr old bike with no seat, so obviously I wasn't able to test ride it. I was actually just looking to get it riding for as close to $0 additional as possible so I could make an informed decision on whether or not to have the shop overhaul it for me.

To that end, shop number 2 did have something like the linked hardware and put it on my post this afternoon for $4.87. They warned that the threading on the seat post (pictured) did not exactly match the threading on the cupped washers and that it might be an issue. Sure enough, it held tight for about 2 miles and then slipped. But the bike rode well enough otherwise that I have no hesitation now springing for the new post.

Thanks again.

Tighten the nuts to 15-20 lb*ft and it'll hold just fine.