Terry Butterfly vs Thomson seatpost

[Miranda]

Yea... what Andrea said. Finding a good bike fitter (yes, the kind you $pay$ to measure you etc.) is an enlightening experience if you have never done so. I'm getting a new ride to resolve the mystery of why all my stuff hurt on my TOO big bike. The fit was worth every penny!

My point is that the fitter will be able to tell you what geometery will give you the best KOP (knee over pedal) position. Like ok... maybe the Thomson (which are great post for adjustability & in general) is not enough set back. That's a limiting factor about them (they offer one set type of setback post). Plus, how far back you need to go depends a lot on the STA (seat tube angle) of the bike.

If you are smaller, like me, one thing that happens in an effort to shorten the top tube in smaller bikes, the STA gets steeper. If you try riding dead in the center on the saddle (like the mid point of that Terry saddle), your knees are all scrunched up and hurt. When you start pushing back to compensate for too steep of a STA to get your legs stretched out right, your reach increases... and body/pelvis rolls forward to get to the bars. Part of my issue--*all* the saddles I tried hurt cuz of this.

Sooo... short of the long answer is that of how close the bike geo on STA is to what your legs need--and is current combo of post & saddle enough set back +that (geo). Look at the bike specs (if not with your booklet when bought, google manufacturer on line for a chart) to see how steep it is. If you got both of the post & saddle all the way back, and your KOP is still cramped up/not right--it's not enough then. PLUS--what's the geo/STA on your old mtb? Compare the two (old mtb & new mtb) geos. Did everything feel ok? If so, try to match that???

This is not the greatest link, but the header line says that the Thomson Elite set back is 16mm (1.6cm). If you go to Thomson's web site, they state some info about the longer rails. Like it's to offer more strength support structurally.

http://www.bike-x-perts.com/en/produ...ucts_id/132908

Plus, here's a link to Thomson that talks about their rail length and design.
http://www.lhthomson.com/elite_features.htm

So I think 6cm sounds about right (5.6cm=4cm+1.6cm)... 4cm in the Terry saddle fore/after rail, plus 1.6cm w/the lay back of the Thomson seat post angle.