alxsmlv

Hello,

I have a Giant TCR that comes with an oversized steerer tube (OverDrive 2) which is 1-1/4 inch. I really like Zipp's Sprint SL carbon stem that is 1-1/8 inch, so it is smaller. Are there any options to fit such stem on the oversized steerer? Maybe expanding the stem clamp in some way so it fits on the steerer? Or use brute force?

I know it might seem a silly question (probably was asked ten times already) but I am curious what are the options (if there are any), in before changing the fork with the correct steerer or simply buying the right stem.

Thanks

Kontact

No. There is absolutely no safe or cost effective way of doing this.

HillRider

Agree. You really have to get the right size stem. 1-1/4" steerers (and headsets for that matter) are pretty rare so you are going to have to do some searching.

79pmooney

Or have someone make one for you. (I have bikes to common standards but arms that aren't and have custom stems on most of my bikes.)

TiCycles has made most of mine. For them it is pretty straightforward although not cheap. They outsource the clamp for 31.8 bars and they'll make any shim you need to go smaller. Steerer dimension, length, angle - whatever you want. But they aren't cheap.

Iride01 

If the stem means that much to you then you should sell the TCR and buy a bike you can use that stem with. Or maybe just set it up on the mantle so you can gaze at it in the evenings and dream about how much better that TCR will have been if Giant had only designed it for and put those stems on it.. <grin>


Welcome to BF!

Kontact

The OP can get 1.25" Giant stems, but likes the aesthetics of the Zipp stems. Are you suggesting TiCycles is going to make him a 1.25" Zipp stem? He wants a Zipp stem.

Shimagnolo

Years ago, when I attempted to install a new stem on a Cannondale M700, i discovered it had a 1.25" stem.
After much searching, I finally found what I needed from a tandem shop.
It is branded "Santana", but looking at Santana's site, they list "Control Tech" stems now:

https://santanatandem.com/components/

SoSmellyAir

Well, alxsmlv can buy a Zipp Service Course SL OS stem for 1-1/4 inch steerer: Service Course SL Stem | ST-SC-SL-B2 | Zipp (sram.com)

I am generally all for CF upgrades, but I don't see the point of a CF stem, which does not save any weight compared to light weight Al models.

Crankycrank

IMO it's a no-brainer to just get the right stem. Changing the fork brings up all kinds of potential issues such as finding another fork that has the same rake/trail, length, same disc caliper mounting, color, new headset bearings,etc.

oldbobcat

And getting a top bearing with a 1-1/8" ID and an OD and bevel that matches the head tube on the giant. And would cost $300-400 for the privilege of such a fishing expedition.

wheelreason

Don't listen to the nay sayers, use percussive brute force and make sure to post pictures and videos of the process, sanding your rims and drilling your tires will help it fit better...

FBinNY 

It may not be cost effective, depending on access to the required tooling, but it's not impossible.

A 1-1/4" steerer has a 1-1/8" ID. So, an expandable tube can be fitted and extended above the existing tube. You'd also need a structural washer to be a base for the stem and allow it to press a stack of spacers and load the headset. A long expander draw bolt would complete the job, doing double duty as expander bolt and headset loading bolt.

If I were doing this (not that I would) I'd also consider cutting the steerer down to reduce the overall stack height. So, while it's not ideal (or even close) is is doable if, for some reason or another, one is committed to using a 1-1/8" stem on this bike.

Now that the OP knows it can be done, and how, It's his decision whether he wants to or not.

Kontact

Where does one buy an expandable 1 1/8" extension tube?

Why would it be safe to put an expander in a carbon tube? The steerer would almost certainly split.

FBinNY 

FWIW, I offered this as a mental exercise, and thought I adequately I qualified it as such.

In any case, the reference to "adequate tooling" implies making rather than buying. Also, it's not at all difficult to use an expander to generate enough traction for the purpose without damaging a CF steerer.

Kontact

Stems have a hard time generating enough traction to keep aheadsets from working loose, and they have a considerable advantage in clamping than a tube that expands on the very end.

I guarantee you that an expander inserted and tightened enough to prevent the bearings working loose would cause the steerer to fail at the base of the expander, causing a horrendous accident. Carbon has very little crush strength, but we get away with clamping stems because that is compression and there's a plug. An unreinforced steerer being pushed out would yield almost immediately.


That's some extremely dangerous advice. It doesn't take much more than a few items from the hardware store make what you describe, so it wasn't a silly hypothetical that no one would do. Hopefully no one ever reads your post without reading the follow on, because your idea could get someone killed.

Please delete it.

FBinNY 

Every of your objections is surmountable. Also my closing sentence was an argument against it.

So, sorry, but I'll let it stand as is.

alxsmlv

Thanks for the thought, interesting. What about doing something to the stem? It's a carbon stem but I just thought maybe there is a way to expand its clamping area somehow? Could it be possible to use sandpaper or something similar to sand down the carbon? Do you think this would be a more practical or realistic way of fitting the stem?

HillRider

Instead of making a metal steerer extension/reducer why not make a carbon one and glue it in place using a strong epoxy.

FBinNY 

This is an example proving my no.1 rule.

There are no rules; it's always about the situation.

So, the answer depends on how much material and it's strength. Is there enough to remove 1/16th inch per side, and is there enough left to do the job?

It's fairly easy to make this call with metal, but with CF, you'd need to know where the CF is vs. resin.

Whether and how you opt to procede, keep in mind that there are other considerations, so it becomes a complicated judgement call. odds are you'll encounter unforseen issues to overcome. It's a case of whether there's sufficient reason to bother, and your own skill set.

As always, being able to do something, doesn't imply that you should.

squirtdad

as noted before, no practical options

Anything else is a theoretical kludge at best, more likely non workable in reality

failure in the area of the fork/stem is likely painful

Just use the right size stem

oldbobcat

And how many layers of structural carbon fiber do you think would be removed in reaming 1/16" of material from inside the clamp?

oldbobcat

Or JB Weld, right?

Kontact

Because the clamping force from the stem coupled with the bearing vertical load would destroy the bond.

Absolutely not. Reducing a lightweight stem's wall thickness by 1/16" means it will break. They don't include extra material for no reason.

Why aren't you taking the excellent advice to buy a 1 1/4" Zipp stem instead of inquiring about complicated forms of suicide? The people egging you on have zero experience with anything being discussed.

Kontact

JB Weld is epoxy. Just with less shear strength because of the filler.

Kontact

What does this mean? Carbon fiber composites put the resin everywhere there are carbon fibers, and nowhere else. Your statement is like talking about a cake having sugar in some places and flour in others.

Should you be advising people about modifying a technology you don't understand the basics of?