Saddle angle

[bunky]

I recently got a new frame. The seat-tube angle is fairly extreme--akin to that of a downhill bike. I have a thomson (non-setback) post in there and it does have the 12 degree head. The word "front" on the head is set in the front facing position. Nevertheless, even with the front bolt all the way in and the rear bolt all the way out (but still tight) I still can't achieve a perfectly level saddle position--in this position, the saddle is still pointed up a few degrees. I am used to riding perfectly level--i.e. with a level positioned across the saddle from the tail to the nose it is perfectly level and the nose sticking up that little bit is making me unhappy.

Anybody got any advice? I assume there is no "shim" kit one might use to get the nose down as it would make the saddle dangerously unstable, right?

[Dirt]

Thomson makes seatposts with the regular clamp and a 12 degree clamp. I was reading about these last month because I was shopping for a post for my unicycle. This is how Speedgoat describes the Thomson Elite seatposts:

Thomson Elite Seatpost
• Post and cradle machined from a single piece of 7000 series aluminum
• Accomodates seat tube angle of 62° or more
• 41mm seat rail grip length
• Available in five lengths and most seat tube sizes
• Finished in gloss black or silver
• Available with 12° clamp for hard-to-fit saddles


If the seat tube angle is such that it is at less than 62 degrees at the top, then you'll need a different seatpost.

The example of one that I found was a Moots, but I'm sure you can find something with a clamp like this for a bit less coin.

http://www.speedgoat.com/images/products/125585-t.jpg

Hope that helps.

Pete

[Dirt]

Race Face DH seatpost has a similar clamp.

http://www.speedgoat.com/images/products/118365.jpg

My guess is that if you look for a DH seatpost, you'll find the adjustability you need.

The more obnoxious and less helpful solution would be to just raise your handelbars 12-14" and have a much more relaxed riding position. That might be better done with a slightly different style of bike though.

http://lowriderbike.com/events/05winlrb_supershow_09z.jpg

Pete

[bunky]

Strangely, the frame mfr says the seat tube angle is 69 degrees. So the Thomson should work. Could it be that my saddle is whacked? It is a Crapformance saddle--I know--but I got used to it and either it now fits my butt just right, or my butt has molded to it--whichever, I like it a lot.

I was thinking this might work, but I guess I would have to check with Jenson to make sure it has enough range:

http://www.jensonusa.com/store/product/SE402A08-Titec+El+Norte+Seatpost.aspx

[bunky]

The more obnoxious and less helpful solution would be to just raise your handelbars 12-14" and have a much more relaxed riding position. That might be better done with a slightly different style of bike though.

Who you tryin' to get crazy with, ese? Don't you know I'm Loco?

[Dirt]

Strangely, the frame mfr says the seat tube angle is 69 degrees. So the Thomson should work. Could it be that my saddle is whacked? It is a Crapformance saddle--I know--but I got used to it and either it now fits my butt just right, or my butt has molded to it--whichever, I like it a lot.

It may actually have an effective seat tube angle of 69 degrees. My wording was specific... the seat tube angle at the top of the seat tube. Frames like the Maverick ML-7 have an effective seat tube angle that is relatively steep, but the curved nature of the seat tube makes it so that the seat tube angle at he top is quite slack.

http://www.maverickamerican.com/i/frames.ml7-over.jpg

If you drew a straight line between the center of the BB spindle to the base of the seat clamp and measured the angle of it, you'd come up with a seat tube angle of 73 degrees (Just a total guess on my part. I don't know what the actual angle is) even though the measurement of the angle of the seatpost might be significantly slacker.

Does that make sense?

Pete

[Dirt]

You might also find that asking the frame builder for a seat post recommendation might be the best way to find what you're looking for. I know it isn't always possible.

Pete

[CountZero]

Thomson claims compatibility with frames having seat angles as slack as 62 degrees. And, in fact, on each seatpost you can see hash marks up to the complementary 28 degrees.

Something's funny about your saddle, I think.

I was just looking at my bike, which is almost the same as yours, and with a Terry Fly there's plenty of room for adjustment.

If your saddle rails are at a comparatively wide angle to the plane of the seating surface, then there will be a problem.

Assuming that Thomson measures according to a standard saddle with rails parallel to the seating surface, if your seattube is at 69 degrees, then your saddle rails can be at no more than 7 degrees from parallel.

The easiest solution is to get a new saddle.

If you really want to get a different seatpost, I would suggest either a Bontrager or Race Face.

The Bontrager posts are very hard to find afermarket. The "Race" is what you want.

The Race Face posts are nice but relatively heavy. The "Evolve DH" is what you want.

[bunky]

Not to worry--the Titec El Norte is in the mail (at half theprice of the Thomson :mad: ) and in keeping with Pete's Low Rider Bike shots it says "El Norte" on it in "Vato" script/font.

Thanks all.

[bunky]

Geez Pete--you must be clairvoyant--that Maverick 7/5 is the same COLOR as mine!

[Dirt]

Actually, the ML 7/5 is the exact frame Bunky has.

Hahaha. That is kind of weird/scary. The Maverick was the first frame that popped into my head when he was talking about slack frame angles.

Pete

[joep]

Bunky,

This (http://www.betterbikeseat.com/) should solve your problem.

You're welcome, in advance.

[bunky]

Bunky,

This (http://www.betterbikeseat.com/) should solve your problem.

You're welcome, in advance.

It's a good start, Joe, but I would want the "donut" version.

Bunky<----has hemorrhoids REAL BAD!

[BikerMiker]

Is the clamp that says 'front' on there backwards?

Just a guess.

mike

[CountZero]

Bunky said:

"The word "front" on the head is set in the front facing position."

[DaveG]

Bunky<----has hemorrhoids REAL BAD!

TMI, TMI. :eek:

[pirate]

Bunky,

This (http://www.betterbikeseat.com/) should solve your problem.

You're welcome, in advance.

Ha! I thought that was a joke at first. Did you see the guy in full on leg armor flying through the air?!

[CRAIG2]

I dare someone to show up at Gambrill with one of these... heheheheheh

[BikerMiker]

Is the clamp that says 'front' on there backwards?

mike

What I meant was, is the seatpost in backwards and the clamp that says front facing the actual rear of the seatpost? Front is front unless front is back.

Man, a brother has to be pretty specific around here...

mike

[bunky]

What I meant was, is the seatpost in backwards and the clamp that says front facing the actual rear of the seatpost? Front is front unless front is back.

Man, a brother has to be pretty specific around here...

mike

I see what you mean. You know, I don't know--I'll check. I thought the posts themselves were symmetrical so that the through-bolts would pull from the same position regardless of whether the post were situated in one position or 180 degrees from that position in the seat tube. I did look at the post itself and it seemed pretty dead-on symmetrical--with the only difference being whether you wanted to look at the Thomson degree reading from the drive side or the non-drive side. Since it's not a setback, I figured I could just slap it in there one way or another and it would be all good. But I'll check.

Thanks for the idea, Mike.

[riderx]

edit: nothing to see here

[middle-ring]

Sorry to chime in so late...I was trying to ignore this thread. I had the same problem with my Thomson last year. The post itself, as you already described has a "front" to be sure, but the clamp on the top does too, and the bolts are different lengths too. Take it all apart, switch-a-roo the clamping hardware with the post in your hand prior to re-installing it, and you will see. I finally figured all this crap out on ride, and set everything corectly in the middle of the trail. Now the seat is in a cross country position rather than the DH position it was in prior. (It wasn't supposed to be like that.)