Is 50mm of spacers above the headset dust cap safe on carbon steerer tubes?

[Velovelo]

Just wondering if anyone here is safely running 50mm spacers above their headset dust cap for a carbon steerer tube on any bike?

Asking because I would need 50mm spacers on the Falath EVO, to fit the frame to my liking.
Aesthetically, only 20mm out of the 50mm of spacers would pop above the top tube level of that frame.
(Side note: The dust cap is about 10mm already, so altogether, 60mm stacked above the "C-ring")

Basically just want to know what is the max spacers (above 40mm) anyone here is safely using and for how long now?

Thanks!

[JohnnyRabbit]

Most of the time it's no more than a 40mm distance from the top of the upper headset bearing to the bottom of the stem so around 35mm of spacers if you take the headset bearing cover into account.

I think the best bet would be to send an email to Elves and ask what are their recommendations.

[Sebastian]

I’ve never heard of any manufacturer setting a definite limit to how much spacers you can stack.
Also, how much stress this puts on your fork steerer depends just as much on your body weight and on your stem length.
For me personally, I don’t like it when the expander plug in the fork steerer does not expand into the upper headset bearing because I feel this significantly reduces the support that the steerer has against bending stresses at that point.
If I needed to stack that much, I’d rather go up a frame size and shorten my stem. If that’s not possible, I’d look at another frame instead.
However, if you check some of Trace Velos builds, he’s running quite a few spacers below his bars and seemingly has no issues.

[jonathanf2]

Just wondering if anyone here is safely running 50mm spacers above their headset dust cap for a carbon steerer tube on any bike?

Asking because I would need 50mm spacers on the Falath EVO, to fit the frame to my liking.
Aesthetically, only 20mm out of the 50mm of spacers would pop above the top tube level of that frame.
(Side note: The dust cap is about 10mm already, so altogether, 60mm stacked above the "C-ring")

Basically just want to know what is the max spacers (above 40mm) anyone here is safely using and for how long now?

Thanks!

If you want to be safe while running that amount of spacers, you can purchase a longer expander plug. It's a bit more weight, but it'll give you more support to run 50mm spacers safely.

[Sebastian]

If you want to be safe while running that amount of spacers, you can purchase a longer expander plug. It's a bit more weight, but it'll give you more support to run 50mm spacers safely.

I don’t know of any expanders of that length. The long ones I’m using from Deda are 70mm, 40 of which is usually taken up by the stem. So if you got 50mm of spacers and top cap below it wouldn’t suffice.

[Wet Noodle]

expanders of that length

I think I have seen 80 and 90 mm expanders from Chinese vendors (Ali/Ebay). Maybe there's even 100(?)
Google says there is also a 91 mm one from Colnago.

[keno190]

I’ve never heard of any manufacturer setting a definite limit to how much spacers you can stack.
Also, how much stress this puts on your fork steerer depends just as much on your body weight and on your stem length.
For me personally, I don’t like it when the expander plug in the fork steerer does not expand into the upper headset bearing because I feel this significantly reduces the support that the steerer has against bending stresses at that point.
If I needed to stack that much, I’d rather go up a frame size and shorten my stem. If that’s not possible, I’d look at another frame instead.
However, if you check some of Trace Velos builds, he’s running quite a few spacers below his bars and seemingly has no issues.

Attached is the specialized Crux stem spacer allocations. This is manufacturer guidance but I've def seen chimneys ridden hard all over.

https://media.specialized.com/support/collateral/2022_CRUX_USER_MANUAL_ENGLISH.pdf