(Pete Cresswell) said:I've got two Thompson posts.
The straight one says "0-Degree" on the clamp
The setback says "12-Degree" on the clamp.
I thought the meaning of each was pretty obvious until a
framebuilder sent me a spec that included the phrase:
"Requires a center mount post with 12 deg clamp."
Called them on the phone...and I *think* they said "Yes,
this is a straight post
(i.e. no setback) but Thompson shipped their posts with two
different kinds of clamp. Old ones were zero-degree
and newer ones are 12-degree."
But I still think I'm not getting it. Eyeballing the clamps
on the two posts I have, I can detect no diff except for
what's printed on them.
From lhthomson.comSP12X.htmlOpen ↗ :
"Thomson now offers only 12° Seat Clamps on all new seat
posts. This has been the case since April, 2002. Thomson
also offers 12° clamps as replacement clamps that will fit
any Thomson Seat Post ever sold. The 12° clamps are direct
replacements for the 0° clamps in every way.
The 0° clamps are good in every way and should not be
replaced unless you need the one thing the 0° cannot do that
the 12° can. That is, the 12° clamp can bring the nose of
the saddle down 12° more than the 0° clamp. As rear
suspension was developed and became more popular the seat
tube was laid back so much on bicycle frames that the 0°
clamps would not allow the nose of the seat to be adjusted
down enough.
The 12° clamp has "FRONT" printed on one end. In the vast
majority of cases the word "FRONT" should be placed toward
the front of the bike. But, if the front of your seat will
not come up high enough, it is perfectly acceptable and
safe to install the clamp with the word "FRONT" toward the
back. This will allow the front of the seat to be raised
much higher.
Set back seat posts may be mounted with the offset backward
or forward. The 12° clamp may be mounted with the word
"FRONT" facing forward or backward. Mount the seat post and
clamp in the direction that fits your riding style.
Bicycles with seat tube angles of 70° and above (70° thru
90°) work well with 0° clamps. Bicycles with seat tube
angles less than 70° (63° thru 70°) require the 12° clamps.
The customer has had the option to buy either 12° or 0°
clamp for about five years. But, not since April, 2002.
There may be some seat posts with 0° clamps in the supply
chain. If you require the 12° clamps, you should request
your bike store supply a seat post with 12° clamps. If you
have a seat post with 0° clamps and want to use it on a
bicycle with a seat tube angle less than 70°, you may
purchase a replacement set of 12° clamp for your Thomson
Seat Post.
If you order 0° or 12° seat posts from an old price list you
will only get a 12° seat post from the factory. The new
price list only shows one model for each size. It will come
with the 12° clamps from the factory. Remember a 12° seat
post clamp will do everything and more than a 0° seat post
clamp will. A 0° clamp will do everything a 12° clamp will
do except bring the front of the seat down enough on
bicycles with laid back seat tubes (less than 70°).
TO TELL THE DIFFERENCE IN 0° AND 12° TOP CLAMPS: Look at the
clamp from the side. 0° clamps have the seat rail groove
parallel with the top of the clamp. The 12° top clamps have
the seat rail grooves sloping at a distinct 12° angle in
relation to the top of the clamp. Also, see sketches on
intruction sheet. Instruction sheet is available on web
site. (www.lhthomson.com) "
