How To Cut A Road Bike Steerer Tube
ฝัง
- เผยแพร่เมื่อ 5 ก.พ. 2025
- Make your road bike look PRO by cutting the steerer tube. This video has the advice you need whether you have a carbon or aluminium steerer.
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If you look at a pro cyclist's bike, you'll see that they always have cut steerer tubes. Let's face it; no-one wants to have a large protrusion above their stem. Only cut your steerer tube if you have settled on your position on the bike!
To fix this, you'll need to cut the steerer tube. It's a daunting job, but provided you have the right tools; a hacksaw and a cutting guide, you'll be able to get that pro look.
GCN's pro tip is to leave enough for a 5mm spacer on top of your stem.
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Leave us a comment below!
I cut mine way too short, get back and arm pain, but would never admit it to my mates. Bike and I look bloody good which is more important
So low that you can't remedy it even with a stem. Or is a positive angle stem also not good looking enough?
@@TundralTV My comment is purely silliness, highlighting how important looking like a ' pro ' is to some.
@@freeagent8225 I thought it's bit a mix of reality and sarcasm!
Hahaha
Lol. So true
another tip: add a thin layer of superglue on the top of the steeringtube after you cut it. it will prevent any possible delaminating of the carbon shaft.
Hey gcn, I just found out that this 'special' blade for carbon is actually an ordinary blade for cutting ceramic materials. Both are made of wolfram steel and the cutting edge is layered with diamond particles. So if it says it's for carbon specifically, you just pay evem 5x more just for the name.
for cutting alloy steerer tubes, a tubing cutter works superbly... it makes a clean, square cut every time without needing to clamp it down or anything like that. Tubing cutters can be found in the plumbing section of any home improvement store
....or a suitably sized Jubilee clip as a cutting guide. 🤗🤗
Man, thanks for the idea. Appreciate it
Thank you so much for talking about the star nut.
Dan didn't mention it in the last video GCN did on cutting a steerer tube.
I use simple pipe cutter to do this with my alu tubes.
Instead of the special tool to hammer down the star nut, you can also use a socket that is the same size as the inner diameter of the steerer tube. Much better "bodge" than hammering the bolt.
Just putting it out there that with aluminum steerer tubes, theres a metal tube cutter that are available in local homedepot or tool shops, that does the job perfectly fine without needing a saw... I've done it with the tool and it does a fine job!
+GlobalCyclingNetwork the "thing" on the blade used for cutting carbon is called tungsten carbide. There are more expensive options coated with diamond carbide as well.
Please do a video on the steer tube stretcher.
I can't find any reference to this in the comments, although it may be there. Adding 2mm to the cut line is ok as long as the top cap has enough space. The compression sleeve can easily be 2mm resulting in 4mm of 'protrusion'. That only gives you 1mm of space with a 5mm spacer. I have usually therefore cut at the original cut line when cutting carbon steerer tubes. That gives you the 3mm you need.
If you've got one, secure a jubilee clip on the fork steerer tube just below your cut line, if you've got two jubilee clips put one either side of the cut line, you could even use a couple of zip ties above and below the cut line if you cut carefully.
Instead of using a file to finish the edge, use a sanding sponge. Press the end of the steertube into the surface of the sanding sponge, and twist. It will perfectly clean the cut edge with no fuss.
He took so much material off that he created a chamfered edge... Crazy. For anyone watching this, you just want to sand off any little burrs and leave the edges intact.
The chamfered edge is beautiful though.
you should have mentioned that you are not allowed to put any pressure on the saw, especially when working with carbon forks, as it might result in a carbon string ripping out, which will render your fork useless
The likelihood of this happening is nearly zero. If carbon threads actually come loose from the binding resin while you're cutting, then there is something very wrong with the manufacture of your fork stem, and you should throw it away before it fails in the middle of a ride.
If you have a compression sleeve at 4:05 due to how it expands and with there being a rather large support at either end, you are probably going to strip your threads in a head stem before crushing a steerer tube. Even if you go for the flush look.
I've cut many of my carbon steerer tubes with jus a dirty hacksaw blade and then sand down the inside and outside edges. Never had an issue. Definitely measure multiple times before cutting 🤪 and don't forget to service the headset bearings during the process
@gcn carbide grit tile saw blade 😀
A couple of tips after just doing this on a carbon tube:
1. No need for a guide. I used two stainless steel hose clamps - one on each side of where I wanted to cut, about a mm apart, tightened around the steerer tube.
2. Removing and reinstalling the fork on a bike with internal cable routing and hydraulic disc brakes would take forever and involve bleeding the brakes. No need. You can cut the steerer tube "in situ". Just lay the bike down on its side.
3. I didn't like the thought of using a file on the cut tube. Used some P40 sandpaper instead. Worked well.
4. Tube cut with a 32TPI blade. Worked well. Clean cut with no fraying. No need for a carbon blade.
a short tungsten carbide "blade" or "rod" is less than £2 at toolstation. Used for ceramics/tiles etc.
The blade you need is a tungsten carbide blade, the same type used for cutting tiles.
So clear instructions, thanks.
I am just finishing a fun bike build and totally forgot the star-fangled not! (felt like a dingus).. Great video!
I love these workshop-videos!! Keep it up! :-)
I used a pipe cutter. Job done in just a few turns.
I wish there videos showing the conversion from a short threaded tube with quill stem to a new longer fork which shows the details as far as wedges, nuts, spacers. Etc.
but don't ever file downward on a carbon steerer like that, as the individual carbon threads can be pulled down and unbraid. only go upwards.
Hypothetically yes, but the likelihood of that actually happening is nearly zero. If the carbon fibers are so loosely-bound in the resin that they can pull loose so easily, there is something very wrong with the manufacture of your fork, and you should throw it away before it fails in the middle of a ride.
Don't drag the file down like that...you can cause the problem you are trying to fix....just run the file upwards only. AND who put that hacksaw blade in the wrong way round.
This is what happens when you get presenters to do engineering jobs....its like Blue Peter on a bad day!!!
@@ChristopherDowningglad you mentioned it!
I used my index finger as a saw guide. Worked well.
I just used me teeth, didn't even get off the bike.
Just make sure you do it with old teeth (preferrably english teeth) because you cant damage the enamel finish any worse than it already is.
Rather than spend the money on a guide, I just tape two spacers either side of the cutting line and that gives you a perfectly straight guide to cut against.
Good idea.
wibblemania FACTS
Thank you
Si might be the only dude that can get away with that much vocal fry
I am a schoolboy racer, I have been lowering my stem every month or so until I have slammed it. I have one spacer to go. The. I have the decision, to cut my steer tube. Which, whilst I'm still growing (hopefully) I am not sure if this is a good idea or not? Any ideas, GCN or experienced riders welcome. 😃
Thanks in advanced
Question: Could you/should you use a compression sleeve instead of a star nut in an alloy steerer? I feel like the added grip afforded by a compression sleeve would be a bonus, regardless of the material used in the steerer.
yep, we've done it before and it works.
Haven't had much practice with a file have you, Simon?
Very instructive. Thx!
Thanks for the tips guys !
If you don't want to mess with a starfangled nut, you can still use a compression plug in aluminum steerers.
Ah...literally just asked that question. Should have scrolled down! Thanks.
Or you could use ur stem and imply put a thin spacer above it. Spacers are cheap, even if they get scratched just flip the scratched side down and you can still use it
I thought a star fangled nut was an overly patriotic American ?
tobortine wheeeeyyyyyyyyy!
Im American and that's funny 🤗 loosen up
Ha! That's pretty funny. XD
Not bad, not bad at all. Haha.
7:15--DJ Si putting down some old-Skool vinyl scratching.
I will only substruct 3mm even with that protruding expander?
I have always said, "No one likes an unsightly protrusion", it's reassuring to hear you agree.
Unsightly protrusions are not very aesthetic
@@gcn love you guys, such a great channel. Makes being an avid cyclist just some much more enjoyable. Cheers.
I just tape old spacer as my cutting line guide. 20mm will be straight enough. Too thin will wiggle around
"You should also wear a mask" then proceeds to not wear a mask. Set a good example Simon!
tbf you couldn't actually see his face during the cutting
@@SiRushBass Not for long, but you definitely could: th-cam.com/video/mU-I-Qd6hCw/w-d-xo.html
@@SiRushBass ............"to be fair" -Letterkenny
A mask! Why not use rubber gloves, goggles, pads and boiler suit too, just to be a full on pansy.. You might get something in your eye, knock some body part against something hard or get dirt/oil on your clothes.
@@Alan-75 omg, you're so right... Respirators ARE just for pansies!
I bet you're so tough you don't even wear one when dealing with loose asbestos.
I've Never cut carbon fiber on a bike, but I have for model aircraft. When ever I do though, I rub a thin layer of carbon fiber epoxy resin, or Cyanoacrylate to help protect the cut or filed areas. Sounds like it would make since to do that here too. Any thoughts?
Hi Reuben! Not to be the Grammer police here or anything but your last sentence " Sounds like it would make since to do that here too." I think what you meant was sense not since. Just want to point that out.
Yes, it makes sense to seal the cut edge with CA glue -- not to prevent fraying (the binding resin can do that on its own), but to prevent water from soaking in and potentially de-laminating the carbon fibers over the years and decades to come.
@@MarshWaha: *GRAMMAR* police, not grammer police.
Shawn Elliott 🤣🤣🤣
Yup it works
I can't even imagine trying to ride at that seat/bar angle. Crazy....
Pro tip: Carbon specific saw blades are quite expensive. You can buy a tile cutting blade for less than half the cost which is essentially the same thing as a carbon blade.
Parks Tools carbide blade is only $8.
Does the hacksaw blade have to be in backwards or will it work the correct way round too? :)
WillEyedOney what do you mean by barcwards?
the 'back' of the triangle will be towards you.
The teeth were facing backwards, the arrow was pointing towards the handle.
WillEyedOney sorry, didn't spot the arrow.
It will cut if in the wrong way, but not as well. Pulling pulls the blade down towards you and into the material, pushing takes more effort to do the same thing (and is less controlled). so the teeth should always be at the back.
NO! Hacksaws are meant to cut on the PUSH (most saws for that matter) but some people like to flip the blade for personal preference. Literally 99% of the time the hacksaw blade will be set for cutting on the push, i.e. the vertical side of the triangle (the tooth face) facing AWAY from you.
Doesn't matter with a carbide grit saw blade like Simon used to make the cut.
Search for Raoul Luescher and his channel ''Luescher Teknik'' if you wanna learn about carbon.
Third time he says "now there is a risk" I said fuck it, I'm definitely taking it to a shop
If you don't trust yourself, or you don't have the skills take it to someone who does, even as an engineer i sometimes o that.
Unsightly protrusion....I got the joke. Haha - Si's mini pump.
I thought poeple in this channel know alot better than any other else on cutting an aluminum tube.. I just laughed hard at him cutting it with a hacksaw... This explains about none of them had thought of an aluminum pipe cutter which cuts an aluminum tube evenly and precisely without worrying that you might cut them unparalleled. 😂
I have just cut my unsightly protrusion off!
That's a Tungsten Carbide grit hacksaw blade in case you wanted to know Si :-)
This is why I have never seen the attraction of the Ahead stem system. A quil stem is so simple to adjust to any height required, and can be done at the roadside if necessary - even a girlie-girl like me can do it!
There is no cutting in a workshop, no need for special no-good-for-anything-else tools, no toxic dust and no bother. And a quil stem is neater and more elegant.
Will someone please tell me if I am wrong...
annoyingly had to replace my road bike fork so moved to a threadless carbon one from a threaded steel one.
The big issue I have is the dumb ugly ass stem, unlike my wonderfully elegant & slender alloy quill stem. And I just know with threadless I'm always going to be wondering if I've got the headset bearings pre-tensioned properly - and if they're not then it'll cut rings into the carbon steerer which then has to be thrown away!
Now I have to strip off my handlebars of all its furniture just to get them out of the quill stem too. It's gonna be a shock for those bits since they've spent their entire life there!
I also had to source a 1" threadless headset for the conversion from threaded, which was not easy. Fortunately I found a Tange nice and cheap at Condor Cycles but it wasn't easy since no one touches 1" anymore.
Does this make me a girlie-boy ??
my bike as three 1cm spacers and I want to remove two of them, so I cut 2cm off, no need for those extra 3mm, right?
I will be ordering the parts for my new bike soon. I have decided on the scott addict frameset, Enve 4.5 ses wheels with chris king hubs and red bar tape. i was hoping to get your opinion on groupset though, si. I like the look of the Rotor Uno hydraulic system but dont know whether i should just play safe and go for Di2.
i know you did a couple of reviews a few months ago on the rotor uno, si, and wonder if they are as great as you made them seem. cheers.
Star FANGLED nut? I believe that's star-flanged, a nut with a star-shaped FLANGE:^)
Torque of expander insert?
Get that bike reviewed asap! I assume its your new steed?
Can Simon show us his new orbea orca
Eoin Mellon m
Use the whole saw blade Si!
hi i have 2 pinarrelo F10 and my size about 5'6.5 tall.how i can measuring my arms and my back so i can know for sure closed headset length so i can cut it to make it's close fit what ever i can.......can u help me thanks??
Instead of using an old stem as a guide use a simple hose clamp. Much easier to get a hold of if one doesn't have a stem lying around.
I wouldn't recommend filing the carbon steerer tube with the back-forward motion.
Note, when you file you should only file in the direction away from the tube so you don't start demamination...
I remember the good old days when you could adjust the handlebars & stem up & down as many times as you wanted just by using a Alan key.
palmer3977 still possible duh
I have a Specialized Venge that has a glued steerer nut. Is this a normal S-Works setup?
Instructions not clear enough. Accidentally dropped my car up stairs.
Hi guys! My problem is exactly the opposite, I would need to add some cm to the stem of my road bike. Do you know that BBB BHP-22 extender is safe enough? Thank you for your help!
You can also swap for a stem with a bigger angle to get up higher. If your stem is flipped down too you could just flip it up if you haven't already tried that. Specialized makes handlebars with a 15mm rise built in too. All of these are certainly safe. I have wondered your question myself but don't know.
Yes, I flipped it up. But the first owner cut too much (for me), and now I see I have to do something because there is much pain in my neck. Thanks for the answer!
I would get a 17 or 20 deg stem then, it's a lot easier than changing handlebars.
The saw guide should be sg-8, thats the right one for carbon saw blades. The sg-6 is for aluminium/smaller blades.
I adjust my stem by undoing the allen bolt at the top, moving it up or down, and tightening the allen bolt. Quill stems rock. What is this "carbon" that you speak of? Sounds crude and ungainly.... (but I do agree that no one wants to see an unsightly protrusion...like Dan).
I don’t have any hacksaws, but my university does have a plasma cutter, does that work on carbon?
Is the added space on top necessary with an aluminum steer tube as well or just a carbon steer tube?
Cristal clear as an unmuddy lake.
#torqueback. You should team up with the slow mo guys to do tech videos. Slow mo if a derailleur working would be cool. You could show difference between good shifting techniques versus shifting under load.
if the expander is correctly installed there shouldn't be a problem with putting the cap flush on the stem.
What if the road bike steerer tube is made out of steel can I still chop it off🔥
Does anyone know if it's recommended to use an alloy stem on a carbon fork?
Is it normal for a carbon fork steerer to chafe when installing a stem?
That's nice
my roadbike has a threaded steerer, I know it's an ancient frame but I'd like to cut my threaded steerer down from some similar but equally antique forks
What would the difference between a race bike that isn't slammed and an endurance bike that is be? How similar would a slammed endurance bike be to a race bike?
+Calum Neill it depends on the size of course for comparison, giant for example has the same top tube sizes across TCR and Defy, but propel is slightly bigger. A full rise TCR (race) will overlap with a slammed Defy (endurance) in the same size. The TCR will still have a longer reach if you keep the same stem. You could never get the max height on a TCR that you could on a defy, but with +17 deg stem you can get a lot of height if you want, same with a -17 on a slammed defy you can get way low. You can also get a smaller size frame for endurance and a longer stem and achieve the same position as a race bike.
thanks
"Use an old stem..." *pulls out $200 carbon stem*
wrap the post in tape.. for a cleaner cut
i wouldn't have gottin it flush if I didnt see this!! cheers
which pinarello is that @ 1:30
Please please align the FSA branding on the headset. Either in line or square to the stem, just not skew whiff how you've left it now. ta.
Yeah, that's definitely the important part. _[rolls eyes]_
Oh say does that star fangled
Why not use a pipe cutter? I’ve used one on all my bikes since i was a kid using my dad’s tools. Depending on the material being cut, it’s faster and cleaner than using a hacksaw
agree, on steel/alloy steerers they are fantastic.
Hi guys,, I have a carbon steerer tube with an expansion plug. I've been told it is unsafe to place spacers above the stem. Is this correct? I believe Specalized in their buff advise this.
Yes this is quite possible as the expansion plug is being used to support the clamping force, therefore depending on how long it is may determine how many if at all spacers you can put above the stem.
Why a hacksaw instead of a pipe cutter?
Timothy Fish I'm late to the party but... a pipe cutter has the potential to compress the tube, deforming the cut.
Who makes those compression sleeve? Anyone know please link it
Pretty much any bike retailer sells them. I got mine from PlanetX. Search "Carbon Steerer Fork Bung". They're £4.
so... What was that nut called again?
isn't this kind of a rerun? I swear I've already seen them do this.
this one is more well informed though.
I cut it 4 mm to short. Fml. What to do now?
Its carbon full slammed
Is there any tangible benefit of doing this beside look factor?
Maybe worth doing this vid again, been a while.
GCN used a right tool to cut that stem :p Only joking Si
A while ago I saw a laser pointer to turn your handlebars straight. can you please give me a clue where I can find one?
hi, thats made by Tune.
thanks
Jon
Never cut mines, makes selling the bike much easyer, and i always have to sell old bikes if want another one :c
Not setting your bike up to suit you is like not having sex with your significant other to keep them in good nick for the next bloke 😅