ttusomeone

I have the new twin bolt designed Enve seatpost and am having trouble with my seat rotating backwards. It only rotates down a couple mm but it's noticeable when it happens during a ride. I'll fix it and it's fine until I ride off-road again (I have the seatpost on my gravel bike). Does anyone else have this issue and have suggestions? Am I tightening the two bolts too tight, or not tight enough? It's slipped when torqued to spec.

WhyFi

I don't have this seatpost, but the clamp on my Domane is somewhat similar in design (clamp that rotates inside of a hollow in the post). I wonder if it would be worthwhile to add some fiber grip/carbon paste to the interface between the upper rail clamp and the top/inside of the post hollow? I'd try that first rather than potentially over-torque.

ttusomeone

I'm talking about the new design seatpost, which uses two bolts and a double wedge system versus the single bolt system Trek uses (granted I haven't looked at a Domain recently so it may be the same type of seatpost clamp style now). https://www.enve.com/en/products/seatpost-300mm/

Chi_Z

sideways bolt seatpost will slip unfortunately, same thing happened to my specialized pave sl, since then I have switched to front and back bolts

ttusomeone

Thanks for the replies - but I'm looking for experience from someone with this actual seatpost since the twin bolt wedge design is only used on this style Enve post (that I'm aware of). They designed it to not slip and as far as I can tell, no one is having issues with it slipping (except me), so I'm wondering if I'm doing something wrong.

jamesdak 

That's what Enve told me to do when I had trouble with mine slipping.

ttusomeone

Do you have the new model post with the two wedges and two bolts, or the older single bolt design?

WhyFi

Yeah, I understand that, but it still uses friction against the inside diameter of the hole in the post that houses the clamp. If you don't have enough friction, it's going to slip. You can add friction a couple ways: tightening the bolts, which pushes the surfaces together with more force, or adding grit. If you've reached your torque spec, that eliminates one of those options.

Pizzaiolo Americano 

My experience with the Domane is to do the opposite. It has to be greased. This allows you to torque it down to proper spec. Without the grease, the press fit (or cup/cone fit...) isn't as good. Can't comment on the Envy though...

WhyFi

They're different designs - as you say, the Trek clamps are slightly conical, so tightening the bolt draws them together, pushing on the inside bore of the seat mast clamp. The top of the ENVE clamp doesn't do that - two bits of hardware (with the tightening bolts) go under the upper portion of the clamp. Tightening those bolts presses the upper portion up, against the top of the inside bore. I think that adding grit to those mating surfaces (top of the top portion of the clamp and the top of the inside of the bore) makes more sense than grease.

ttusomeone

This is what I'm going to try. Based on the design, I'm not even sure how it's slipping but this is the only thing I can think of.

Mr.Maselan

I’am also having the same experience, did you fix it already? What did you do?

ttusomeone

Yes I was able to resolve it. My issue was that I was using a Sworks saddle, but my LBS gave me the 7x10 seatpost clamp (the top piece). After they called Enve, they were told they make a 7x9 that fits the specialized carbon rails. After installing the new clamp it's worked flawlessly.

Mr.Maselan

Im using a specialized power saddle and it has a 7mm rails. Hence im using the 7mm cradle but it keeps slipping upward/downward when i go offroad.

ttusomeone

And you have the new version of the seatpost that uses the two wedges that tighten together versus the old single bolt circular design? My issue was the wedges would bottom out against each other before getting fully tight within the cradle.

rndnrnd

Specialized Power have 7x9 rails. Use the 7x9 cradle.

ttusomeone

Thanks! I've spent these past 17 months since the last post trying to figure it out. In all seriousness, you are correct in that is what the problem ended up being.