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Seat posts without set back(4 posts)

Seat posts without set backandydave
Jan 24, 2003 4:13 PM
Can anyone explain why a few seat posts (the standard Thompson for example) offer no set back? Most seat posts do have back set, but there a few that do not. With my current bike, there is no way I could ride a seat post without back set and have my seat in the proper position. Do some people have body geometries that require their seat to be much more forward? Thanks.
re: Seat posts without set backweiwentg
Jan 24, 2003 5:27 PM
Thomson machines their posts out of a solid block of al. this may have something to do with it, but I don't know for sure. so, before I verbally shoot myself in the foot, I'll answer the second question: you probably have long legs and/or prefer a rearward position (this probably due to lower cadence). some people (like me) have shorter legs (in my case, very short) and/or prefer a forward position (I prefer fast cadences).
Jan 24, 2003 7:07 PM
...Thompson's relatively recent crossover from mountain biking componentry (where setback is not an issue) might have somthing to do with the straight post design.
re: Seat tube angleMike Prince
Jan 25, 2003 5:38 AM
A big factor is seat tube angle. If you have long femurs and a steep (74 deg) seat tube, the straight post is probably not for you. More and more framebuilders seem to be going to slacker seat tubes (72 degrees or so) which can make setback less of an issues.

For what it's worth, I have quite long legs/femurs but my Steelman has a 72 deg STA and I use the non-setback Thomson with no problems. In fact, the saddle is not even all way back in the clamp. I have an older (1985) steel bike with a steeper STA and there's no way I could even use the setback Thomson and get the saddle back far enough. I have an old Campy seatpost on that one and it has tons of setback (at least compared to the Thomson).

So, there are a few factors in play here. Kind of like asking what is the right length/rise stem.