seatpost blues

[Glenn Larson]

OK, so I am riding with my seatpost extended 1/4" past the max
insertion marker...

what's going to happen?

I have a weird size seatpost (30.4mm) on a cro-moly Stumpjumper. The
best path I see is to get a longer seatpost in a 27.2mm size and use a
seatpost shim to make up the difference.

Any comments on seatpost shims (adaptors)?

thanks,

- glenn

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[bfd]

Post by Glenn Larson
OK, so I am riding with my seatpost extended 1/4" past the max
insertion marker...
what's going to happen?
I have a weird size seatpost (30.4mm) on a cro-moly Stumpjumper. The
best path I see is to get a longer seatpost in a 27.2mm size and use a
seatpost shim to make up the difference.
Any comments on seatpost shims (adaptors)?

I don't get it? You willing to risk injury by raising your seatpost a 1/4"
past the maximum insertion point just because *you think* there isn't a
30.4mm seatpost available in your size ?

If you did any sort of search, you would find that there are 30.4mm seatpost
readily available. Where? Any LBS can order it.

No LBS? Check out Sheldon Brown:

http://harriscyclery.net/site/page.cfm?PageID=49&Category=1465


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[Kevin]

30.4 is a weird size, are you sure it's not 30.0 or 30.8 (two standard
sizes). You can cause your frame to split if you land on the seat hard and
the seat is extended past the maximum point. Most of the good seatposts
come in all the standard sizes. Thomson is one of the best.
www.lhthomson.com , they're light and strong.

Kevin

Post by Glenn Larson
OK, so I am riding with my seatpost extended 1/4" past the max
insertion marker...
what's going to happen?
I have a weird size seatpost (30.4mm) on a cro-moly Stumpjumper. The
best path I see is to get a longer seatpost in a 27.2mm size and use a
seatpost shim to make up the difference.
Any comments on seatpost shims (adaptors)?
thanks,
- glenn
--
rec.bicycles.off-road is moderated by volunteers. To find help solving
posting problems, or contact the moderators, please see http://rbor.org/
Please read the charter before posting: http://rbor.org/rbor_charter.txt

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[James Thomson]

Post by Kevin
30.4 is a weird size, are you sure it's not 30.0 or 30.8 (two
standard sizes).

It's an unusual size, but it was used by Specialized for their oversized
steel Rockhoppers and Stumpjumpers. It corresponds to a seat tube with a
31.8mm outside diameter and 0.7mm nominal wall thickness.

RooX make a good (and very long) though expensive one - the S4. KAlloy also
make long, cheap 30.4mm posts in several styles - they're often rebadged.
Ritchey used to make one, and so did Syncros.

James Thomson


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[justen]

Post by James Thomson

Post by Kevin
30.4 is a weird size, are you sure it's not 30.0 or 30.8 (two
standard sizes).

It's an unusual size, but it was used by Specialized for their oversized
steel Rockhoppers and Stumpjumpers. It corresponds to a seat tube with a
31.8mm outside diameter and 0.7mm nominal wall thickness.

My 94 Stumpy has a Syncros 425mm post that size. It cost a bunch, but
it has lasted a decade without problem. The stock Specialized seatpost
on those bikes was pretty short, probably 330mm. That was the first
thing I replaced. I don't think Syncros is around anymore, but the
Thompson post is probably a decent follow-on.

Justen

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[Ryan Cousineau]

Post by justen

Post by James Thomson

Post by Kevin
30.4 is a weird size, are you sure it's not 30.0 or 30.8 (two
standard sizes).

It's an unusual size, but it was used by Specialized for their oversized
steel Rockhoppers and Stumpjumpers. It corresponds to a seat tube with a
31.8mm outside diameter and 0.7mm nominal wall thickness.

My 94 Stumpy has a Syncros 425mm post that size. It cost a bunch, but
it has lasted a decade without problem. The stock Specialized seatpost
on those bikes was pretty short, probably 330mm. That was the first
thing I replaced. I don't think Syncros is around anymore, but the
Thompson post is probably a decent follow-on.

http://www.mountainbike.com/community/article/1,4823,3961_621,00.html

Syncros more or less stopped existing for a while, but the brand has
been revived by Ritchey. It does run as a separate, Vancouver-based
design house. That's not a snipe: what with the outsourcing of so much
manufacturing, a great number of bike and component makers act more as
design houses, or in some cases, assemblers, for a great majority of
their bikes and bits. There are several exceptions.

This isn't to denigrate these production methods, either. The design
expertise can be usefully separated from the manufacturing, for the most
part, and the result is better, cheaper bikes.

Syncros calls its new lineup of parts "generation 2." They have some
carryovers from the old designs, but they don't have a 30.4 seatpost.
Shimming should allow you to use a close size. The Thompson post is the
benchmark in the field these days.

http://syncros.com/seatposts.htm

[Mike Jacoubowsky]

Post by Glenn Larson
OK, so I am riding with my seatpost extended 1/4" past the max
insertion marker...
what's going to happen?

You might cause a seatpost failure or, perhaps worse, damage the frame.
I've seen many failed frames from too-high a seatpost, and it's pretty easy
for the manufacturer to tell what happened (and thus not consider it a
warranty).

Post by Glenn Larson
I have a weird size seatpost (30.4mm) on a cro-moly Stumpjumper. The
best path I see is to get a longer seatpost in a 27.2mm size and use a
seatpost shim to make up the difference.

I'm pretty sure you can still get that size and, if not, a proper shim can
take care of it. Don't improvise the shim if you can avoid it though, as
even a slight mis-match in size can cause the frame to fail (if you err on
the too-small size, the slot closes up and creates a likelihood of the frame
cracking at the slot's base).

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

Post by Glenn Larson
OK, so I am riding with my seatpost extended 1/4" past the max
insertion marker...
what's going to happen?
I have a weird size seatpost (30.4mm) on a cro-moly Stumpjumper. The
best path I see is to get a longer seatpost in a 27.2mm size and use a
seatpost shim to make up the difference.
Any comments on seatpost shims (adaptors)?
thanks,
- glenn
--
rec.bicycles.off-road is moderated by volunteers. To find help solving
posting problems, or contact the moderators, please see http://rbor.org/
Please read the charter before posting: http://rbor.org/rbor_charter.txt

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