Just got a very gently used S5 and I'm getting the fit dialed in. Due to it's tall head tube, I'll likely need (and want ) to slam the stem all the way down with a 'Slam that stem' headset cap. The steerer tube is uncut and it appears from what I can see the insert is uncut as well. My question is this: How long is that insert? It look like I'll need to take 5-6cm off the steerer tube and as such the star nut will need to go in an equivalent amount. If that insert is short, I could just use an expansion plug I suppose, seems like people have done this before.

Any thoughts? Thanks in advance.

Make sure the insert is actually glued in first. many Cervelo dealers just wedge it in at first until the customer sorts their position

Also many have found out that putting a long bolt in the star nut and hitting it with a hammer often unglues the insert before the star nut pops down and out

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Cervelo S3 2011. Blinged 6.718 Kg

R5 insert 70mm.
Get extralite ultrastar, it will save you few extra grams.

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Cervelo R5 VWD 5637g/12.43lb
Cannyon Ultimate slx 5592g/12.33lb
Pronghorn XC SW Race 8284g/18.26lb

Very often the very bottom of the insert has little epoxy, so it won't stay if you cut off that much. It's SUPPOSED to be fully covered in epoxy, but that's how I've seen inserts that were glued elsewhere.
If you try to keep the insert, this may sound obvious, but lower the star nut first, then cut.

Add me to the list of people who have learned that the insert can be problematic due to insufficient epoxy coverage. My friend and I purchased Cervelos last winter during their promotion to buy 2 bikes, and both have had the insert come loose due to poor epoxy coverage. AS with previous advice, check to make sure that your insert is adequately secured.
Don't want to slag on Cervelo too much.... I love my R3 Team otherwise.
Good luck!

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The more you suffer, the closer you get to transcendence.
It's not the mountain you're climbing, it's yourself. If you don't want to know, stay at the bottom.

I just received my S5 too, this is the insert you guys are talking about correct ? Can I cut that inser into half ?

Hello guys,

I do have new R5 VWD, size 56. I assembled the bike and rode like 400km on it. The headtube area seems to me a little bit nervous, not very much stiff. I used to have an R3, 2007 model, size 58, so the lack of R5's HT area stifness surprises me...I expected stiffer HT from the R5.

So, it just came to my mind if the insert is bonded perfectly in the steerer tube or not (epoxy not fully covering the insert). If not, could it play any role in the overall stiffness of the system?
My understanding is that the insert is there to be a support for the steerer tube in cases of crash, not to be there for stifness, am I right?

FYI: I use only 5mm spacer under the stem, the bottom of the insert is deep under the upper bearings.

P.S Maybe I am too strong after winter (a lot of country skiing > my upper body is stronger so the bike seems not being stiff enough )

Thank You for any inputs.