jzm
10-19-08, 02:10 AM
Will running a thomson set-back post in a set-forward position have any effect on the seat tube angle - similar to the effect of a Profile Design fast forward seatpost?
Thanks:)
Thanks:)
Triathlon - Thomson Setback post for tri
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pjcampbell
10-19-08, 03:14 AM
It is not really that much of a set forward. I run the Thomson with my seat all the way forward, because I really like Thomson. The offset is only 16mm vs 40mm on the Profile... so huge difference.
jzm
10-19-08, 05:41 AM
Ok, thanks. But is there an effect on the seat tube angle?
johnopower
10-30-08, 03:12 AM
yes there is, you'll need to crank out some trig to know how big a difference (ie angle), but it does. Then again, moving your seat forward a millimeter also changes the angle at which butt sees the BB :)
That post is a good first step toward riding steep if thats what you're into :)
That post is a good first step toward riding steep if thats what you're into :)
jzm
10-31-08, 08:01 AM
Thanks, I got some info from Thomson - 10deg setback angle for all their setback posts, except for the 410mm post which has a 7deg angle. So, I figured the following (not sure though if this is correct)
90deg - (Seat tube angle 73deg + 10deg setback angle of post) = 7deg from vertical or 83deg effective.
90deg - (Seat tube angle 73deg + 10deg setback angle of post) = 7deg from vertical or 83deg effective.
johnopower
11-03-08, 04:32 AM
thats not going to add up. the 10degree will not change the seat tube angle 10 degrees... you need to measure the offset distance from the centre axis of the post. thimson probably has taht info anyway... i'll stay in touch about it.
jzm
11-03-08, 07:00 PM
thats not going to add up. the 10degree will not change the seat tube angle 10 degrees... you need to measure the offset distance from the centre axis of the post. thimson probably has taht info anyway... i'll stay in touch about it.
It has a 16mm offset from the center axis of the post.
It has a 16mm offset from the center axis of the post.
thehammerdog
11-04-08, 10:57 AM
I use one because it looks cool as far as fit & function when I had it facing forward I blew my knees apart...I now use it set back with seat more forward I have not clue about angles justthat I am comfy and faster:crash: