lightest Fork expander

[dj97223]

I've used the Ultrastar 2, and now the 3, with success. I had no luck with the GumGum.

Just curious, what issues did you have with the GumGum?

Not enough grip/traction. I tried two different GumGums in two different forks. Same result each time. It may be that the inside diameter of these forks did not match the specs of the GumGum. I was able to get enough traction if I wrapped the GumGum in some electrical tape to increase the diameter. Both GumGums were made several years ago, so I can't speak to the current version, which appears slightly different from the two I have.

[pdlpsher1]

The expander isn't supposed to help with the clamping forces of the stem, it's just to preload the headsetbearings until you tighten your stem bolts.

False. Although some 'expanders' are designed to only offer a bearing preload, the OEM expanders are designed to resist the clamping forces of the stem. If the steer tube is made of metal then an expander is not needed. Carbon steer tubes are easily damaged by compressive forces.


Sent from my iPhone using Tapatalk

[esta]

Who told you that?

edit 1:Its basicly the same with handlebar. There is no expander in your handlebar nor is there need for one, even the torque you apply to your stemcap bolts is roughly the same as the stem bolts. Same goes for your seatpost, again roughly the same torque and no expander.

[pdlpsher1]

Who told you that?

edit 1:Its basicly the same with handlebar. There is no expander in your handlebar nor is there need for one, even the torque you apply to your stemcap bolts is roughly the same as the stem bolts. Same goes for your seatpost, again roughly the same torque and no expander.

The handlebar clamp area is reinforced. That's why almost all carbon bars are not approved for clamp-on aerobars. There's only one bolt on a seat clamp so only half of the force is applied on a seatpost compared to a stem clamp.

[esta]

Exactly the handlebar is reinforce and so is the seatpost, only the real light ones tbh. And the exact same thing has been done with the steerer tube, it has been build to resist clamping forces.
You can look at it from another point, if the expander would be safety relevant its exact position would have to be taken into account. Means if you have 3 cm spacers above your stem the expander won't completely sit in the clamping area.

[Tenlegs]

With 3T - Cervelo forks you get a kit like this to epoxy into to the steerer, only weighs 20g and is 80mm long,
the length adds support past the stem into the top bearing area, you should use what's right for your frame/forks, ie check first,
Canyons with Acros expanding type under stem headsets don't use anything - it all depends.

[esta]

They make you glue a pipe into your steerer so that you can use a regular starnut again?
That works no doubt about it, but its a really sad solution. The manufacturer doesn't want to glue a pipe in themself because its costly so they make the customer do it.

[Stockie]

No, they make the customer do it so that you can glue the metal insert in place after you cut the fork to the right length.
I think this is a good bullet proof solution (and lighter than an expander)

[Tenlegs]

Kits are supplied with 3T and Cervelo forks for installing after sizing and cutting!

[esta]

That's a cheap workaround.
Manufacturer could just glue in a pipe that covers for all possible headtube length. The pipe would be only be a little longer adding as much as 5g.

[Tenlegs]

Try clamping a stem to a bare fork-no insert, measure the steerer, notice how it goes out of round when torqued up.
yes you do need an insert to support the stem in *most* cases.

[esta]

Of course it does compress the steerer, it does with Al and it does with CFRP. Thats no sign of bad engineering or that it is faulty, it just deforms under load just as every other part or your bike.
Having a customer reinforce his bike so that it is safe to ride and masking it with "fitting" is ridiculous.

[Tenlegs]

It needs to round as poss for the bearing under it!
Light-Simple-Effective pick three.

[andreszucs]

I use the gum gum with tune cap 9g total. Worked well for me for years

How does that work? con you show assembled?

[UpFromOne]

I've had no luck with the Gumgum either. When I do use an expander it's the Extralite.
And if I read correct, this thread omitted the Schmolke expander:
https://schmolke-carbon.de/product/expander-tlo/

But my preferred solution is the Schmolke plug:
https://schmolke-carbon.de/product/carbon-ahead-plugs/

Precision made to fit firmly in your steerer. Once clamped further by the stem, no possible steerer crush.
And worst case if your stem bolt breaks, there's still some hold-down force such that the stem can't come off the steerer.

BTW, has an expander ever really saved anyone from injury by a broken stem bolt?