Need to extend carbon steerer tube

Hey folks, got a cannondale system six and the steerer has been cut to accomadate 25mm of spacers ( 2 x 12.5mm). I need to extend it higher (the max is 55mm) so my options are 1 x and 2 x 7.5 = 27.5mm which i think I can get away with but ideally i’d like an extra 2.5mm or even more.

What are my options other than a new set of forks which I’ll never be able to find?

I tried 2 x 12.5mm and 1 x 7.5mm (32.5mm) but the top bolt on the stem has nothing to directly bolt to (the fork is 2-3mm too short)

Any help would be much appreciated

You can’t extent the steerer tube easily, but you could contact a carbon repair shop to see if they might be able to do something.

I’m guessing you have integrated bars, otherwise the easiest way to raise the bars is flipping the stem.

What I wouldn’t do is just building the height with spacers with no steerer inside! The sounds like a recipe for disaster.

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Yes I have integrated KNOT bars and as of yet, I can’t find any bars that are compatible with the bike that has a + riser :frowning:

I think 6 weeks of yoga classes might be a cheaper solution to your problem?


Zero options to extend a carbon steerer for an integrated system. Your only choice is to source a new fork and start from there.


Not with my bulged discs ha.

I didn’t think I had much options tbh. Bugger

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I generally don’t like used forks because it makes you wonder what happened to the frame it was attached to. Not sure if 203mm is enough.

How much is a new fork at the Cannondale dealer?

I see these and unfortunately mine is a high mod frame. I don’t think I’d be able to get a new set from a dealer would I if its a 2020 model? Its the champagne coloured one

Maybe try contacting Cannondale?

They may have some forks in a store room somewhere, a friend needed a part for a very old Cervelo, they emailed them and they replied saying they found the part and sent it to them free of charge (it was only a seat post clamp)

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You don’t know until you ask. They can often look up a part and order it.

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How do you contact them direct? I had a look and it just points you into the direction of dealerships

There are special steerer extender thingy that work like extra thicc anchor

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I only have small balls, but don’t think I would dare ride a bike with one of those installed and the stem clamped to the top


Yeah, that looks like an accident waiting to happen. It can vary, but most carbon fork steer tubes are built with the planned use of a stem clamping around the internal compression device. Sort of a system setup with combined strength to handle the various forces.

That plug seems simple at first, but the moment you mount a stem on the upper portion, with enough internal clamping to resist torque at the insert, that fork steer gets pure expansion with no constraint from a stem. Even with spacers under the stem, I doubt those are providing the support intended from a stem since spacers have gaps in all the cases I’ve used.

That insert seems like a risky option for carbon, IMO.

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Agreed, time to sell the frame unfortunately :frowning:


Has the fork changed between the 2020 versikn and now? Otherwise, you could get a new fork and have it re-painted to match the frame?

No its the same fork I believe, its getting hold of one that’s my issue as its a high-mod. UK marketplace is sparse

It seems easy enough to design a carbon fork extension that clamps around the outside of the fork instead of going internal. I must be missing something because none exist. I would suspect the additional moment loading to be a minimal factor.

They are going to want you to go through a dealership first, otherwise there is no point in being a dealer if Cannondale are going to deal direct, granted your problem may be needed to deal with by Cannondale, but they have to have some vetting process otherwise people will just go direct

I’m really surprised a dealer / Cannondale can’t help you out, I would have thought damaged forks would be a issue that they would have to deal with on a regular basis