Weight Weenies

You don't actually get the mast with the frameset. It's a separate purchase. I chose the buy the SLR version!

I did it on my 2014 Madone6... I was not original owner of frame... so trek said pound sand ... I carbon repaired it myself with multiple layers on the inside.

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Calnago wrote:Yes, certainly.... I understand. The clamp itself is smooth. But when it's mounted on the double slotted seat mast, the barrels seem to wanted to push right down on the edges of the two slits, so it's actually the edges of the two slits that I believe creates a stress point on the mast itself. This one seems to have cracked in the same place as the other one, which appears to be right where one of the slits is.

Ok; thanks for explaining. Looking at the single-slot cap and the original clamp, the clamp lines up with the slot edges. This is what I suspect caused cracking in the original design.

If the two-barrel clamp lines up with the edges of the double-slot clamp, that may well have caused the same problem with the new design. The rounded portion of the two-barrel clamp would help spread clamping force over the a large-ish area on cap, but using that clamp with the two-slot cap may effectively cause exactly the same problem as using the conventional clamp with the one-slot clamp.

In other words, it may be that the one-slot cap works with the barrel clamp and not the conventional one, while the two-slot clamp works with the conventional clamp and not the barrel clamp.

At any rate, I'm eager to hear what Trek's warranty department has to say.

I've spoken to the shop who in turn spoke to Trek. The warranty is registered but not confirmed. Shop is pretty certain they will warranty it.

No explanation yet to the cause.

TobinHatesYou wrote:I did not get the weight weenie seatmast cap with my 2018 Project One Emonda SLR. I got the single-slot version.

I did. You didn't miss much (9g).

Geordiepaul wrote: ↑

Fri Aug 11, 2017 6:02 pm

I've spoken to the shop who in turn spoke to Trek. The warranty is registered but not confirmed. Shop is pretty certain they will warranty it.

No explanation yet to the cause.

This just happened to me today. I ordered the sl10 mast because the stock one was too short. What did trek say/do?

Replaced the frame and seat post with the non slr one. Been fine since

Ah, such a frustrating issue. I assumed Trek had figured this one out by now. I've had my 2014 Madone frame replaced 3 times because of this. Waranteed each time. Got the SLR frane last week, with the SL seatmast. Torqued it to the max 8Nm and seat keeps sliding down when riding. Went back to the shop as I didn't want to ruin this frame by going over 8Nm. They're gonna have their Trek expert look at it and possibly send the bike back to Trek. Really, after over 5 years of development of this frame/seatmast construction, the issue is still there.

happened with a Madone6... I was second owner so expected and got "pound sand" from Trek. Carbon repaired my self on the inside..been good for a couple years. I've ridden it a few times but it's my wife bike and she's only like 100lbs

If you have to go over 5nm on a m5 bolt on carbon I'd rather turn to carbon paste or even a few drops of loctite.

The seat mast cap on my Domane SLR kept sliding at ~6-7Nm as well. I added a generous amount of carbon paste and no more sliding.

My lbs contacted Trek about the issue and Trek mentioned they've changed their paint process, which makes the surface of the frame very smooth/slippery. So, they suggested to use some sand paper and roughen the inside of the seatmast, use carbon paste and of necessary, roughen up the frame as well. As of now my lbs did the seatmast and paste and sais this fixes the issue. I'll pick up the bike soon as test it myself. Quite surprised the paint is the issue and I really wonder how Trek test their products before making them available for the public.
They did mention they could roughen the frame beforehand, but they don't like the aestetics of it. Hmm, I prefer a solid contruction over aestetics at all times....

i guess regular seatpost is not good enough for trek?