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Setback amount of Easton EC70 post?(5 posts)

Setback amount of Easton EC70 post?Muskrat
Apr 21, 2003 4:28 PM
Does anybody know the actual offset of the Easton EC70 carbon seatpost? Easton says 43mm but that does'nt seem right. The Thomson Setback is only offset 16mm. Thanks.
re: Setback amount of Easton EC70 post?divve
Apr 22, 2003 4:05 AM
Due to the single bolt sliding clamp design the setback will depend on the following: angle of your seat tube, angle of seat rails in relation to seat surface, and seat angle. My bike has a 73deg. seat tube, seat is an SLR TransAm, top the seat set level, total setback is roughly 35mm.
not quite....C-40
Apr 22, 2003 4:58 AM
First of all there is no standard method of specifying setback. If you are comparing several seatposts to be placed on a given bike with a given saddle, all the other factors that you mentioned are irrelevant. The idea is to compare one seatpost with another.

The 16mm dimension in the Thomson specs merely compares their setback model to their straight-up model.

The Easton 43mm dimension is probably the distance from the center of the seatpost to the center of the seat rail clamp. By comparison, the Thomson straight-up model would have zero setback, and the bent model would have 16mm of setback. While this dimension has some value, the maximum setback is limited by the location of the front of the seatrail clamp. Differences in the length of the seat rail clamp will affect the maximum setback using this method of dimensioning.

Traditional seatposts locate the front of the seat rail clamp approximately at the center of the seatpost. If the seat rail clamp length happens to be 40mm, then the setback would be 20mm. The Easton post would have 23mm more setback than the traditional road seatpost design. If they have a drawing posted somewhere, it would help to clarify the dimension.
not quite....divve
Apr 22, 2003 6:07 AM
I happen to have both seat posts that you mention. The EC70 setback (center of post to center of clamp) will vary depending on the factors stated above. For instance a steeper seat tube will require you to fixate the clamp farther back in order to maintain a level saddle position.

Regarding the Thomson post, their system mounts the clamp exactly above the center of the seat post and allows you to adjust the seat angle without changing the relative clamping position.
All else being equal & going by their "standards"TrekFurthur
Apr 22, 2003 6:19 AM
I'm not disagreeing with any of the above posters, but just wanted to answer the question without the ubiquitous "it depends"--yes the offset they quote is correct, for their "standard;" as above, what happens when you put it on a bike will change how much setback you can get.

However, I will say that I can barely get the 5cm I like on the Thomson setback, have a cm to spare on my DA post, and can achieve 7-8cm setback with the Easton--its setback is huge. May be overkill.