Trek seat mast cap

shiznit76

Hi, I have a 135mm carbon seat mast cap on my Trek emonda SL6 (carbon frame). I want to swap this for the longer one at 175mm, but the alloy version is half the price than the carbon option, could I use the alloy one even though the post coming out the frame is carbon?

It isn't a very good system and leaves you tied in to Trek's own "seat masts"

Thanks

imposter2.0

As long as it is compatible, then I don't see any particular reason why not...

shiznit76

It is right size, comes in the aluminium SL5 version, just wanted make sure there would be no issue with aluminium cap and carbon post coming from frame

Matthewfalle

slap a load of carbon paste in there just to stop it all bonding together over time and it should be fine.

#pastey

imposter2.0

shiznit76 wrote:

It is right size, comes in the aluminium SL5 version, just wanted make sure there would be no issue with aluminium cap and carbon post coming from frame

Presumably the carbon & alu surfaces are painted or have some other kind of coating or finish on them? Assuming they do, then there will be no more issue than there would be in any other similar situation where a carbon post goes into an alu seat tube, or where a carbon stem fits onto an alu steerer. Same non-issue.

shiznit76

D 'oh this sounds such a stupid question now,

Cheers for info

Matthewfalle

shiznit76 wrote:

D 'oh this sounds such a stupid question now,

Cheers for info

don't be a lemon - no question is silly. its what this forum thing is here for.

#happytohelp

loobster

I have a longer grey one for sale (from an 2019 Emonda SL6) if you're interested. I had the same issue but needed a shorter one.

shiznit76

contacted the shop i bought bike from and they are getting me the bigger size,

cheers for help, and sorry Loobster or i wiuld have bought