Really tough inserting a 25.4mm Di2 seatpost - should I be worried?

daniel_b

Should it be really difficult to insert a 25.4mm seatpost into a Carbon Cannondale Synapse?

As Evans supplied it with the wrong length (300mm) seatpost, I had to replace it with a 350mm one, and bought the circlip tool to change the battery over.

It went in the first few mm with no issue, but then became really tricky to get to go down far enough so the saddle would be at the right height - I did put Tacx carbon grease on to aid grippiness, but this was bizarre, as I have done the same on other non Di2 bikes, and had zero issues

Is there anyway the Di2 cable could be getting caught up as it is being pushed down?
I do of course make sure it is not getting caught at the top!

I'm loathe to take it out to look in case it's a right pita to get it back in, but then equally I am worried it might have caught and crushed the cable.

Having said that, if it is a right pita to remove and replace each time, that limits it's used for me, as I was hoping to use it to, on occasion, ride to friends and family, whilst the family goes in the car, and then pop it in the boot with the saddle and front wheel removed for the journey back.

sungod

it may not have needed the tacx compound if it's a tight fit

i'd remove it, clean post and seat tube, then retry, if it goes in easier but doesn't slip then there's no need for the tacx

daniel_b

sungod wrote:

it may not have needed the tacx compound if it's a tight fit

i'd remove it, clean post and seat tube, then retry, if it goes in easier but doesn't slip then there's no need for the tacx

That is a good call, I will give that a go tonight

daniel_b

Update!

Finally had a proper go at this today, along with fitting the Shimano D-Fly unit into the top tube, and we found that conclusively it is the di2 cable that was stopping the seatpost going down far enough.

I popped the bb cover off, and located the power cable coming from the seatpost, and with a helper, was able to have this cable pulled out of the way as the seatpost then descended without any trouble whatsoever.

The law of sod now dictates that as I have already wiped off all of the carbon paste I put on that the seatpost will now probably slip!!!

Anyone else had this?

Seems a bit like p1ss poor design of the seatpost, in that the silver part at the base is ever so slightly narrower than the actual seatpost tube, and the edge of this is in turn slightly bevelled - are other Di2 seatposts the same diameter ALL the way down - that would seem to be the sensible solution.



It's not like there is excess of cable sticking out the top either, maybe 6cm at most.

Oh and for anyone interested, this is the method I found and worked a treat:
http://belgianwerkx.com/2015/06/installing-shimano-d-fly-internally/