How To Cut A Bicycle Fork Steerer Tube

[@gcntech]

Have you ever trimmed a bike’s steerer tube? How did it go? 🚴‍♂️

[@garysladek9110]

Yes, but I read and viewed as much as I could before attempting. Also check the manuals for all parts involved.

[@oplkfdhgk]

nah but i have swapped stem and it was really fun when all the headset bearing bits just went flying. 😀

[@paulgrimshaw8334]

Easy on a bike with a metal steerer tube. Use a pipe cutter, which is available from any decent hardware store.

[@alumal]

Yeah, I used a pipe cutter to cut a carbon steer too, the cut was very accurate. Anyone know if there are brand recommendations to cut the steers always flush to the stem or we can use a spacer over the stem?

[@billkallas1762]

Only when I installed the new fork on the new frame. 1mm under, and 2mm above. The stem was only a -6, not a -17. (130mm stem)

[@fede1275]

It should be pointed out that this procedure is valid only for Canyon 1 1/4"steerers fitted with that small bung (not a traditional compression plug). In this case the bike does not have a reinforcement for the steerer where the stem clamps, as the bung sits below and it's designed for the top cap to compress the bearings only. Other Canyon models would also have a reinforcement ring to support the stem clamping force. All other bikes with 1 1/8" steerers will have a traditional compression plug to both support the stem clamping force and bolt the top cap. In this case when you measure the fork you need to also account for the 2mm lip of the compression plug that overlaps the steerer tube.

[@screscenti]

The music at 6:35 was on point! Felt like I was watching an 80s action bike movie!

[@AMLay1234]

😆

[@ebikescrapper3925]

If you plan to sell your bike having extra stem length can it better for the new owner You also need to file the inner and outer rim of the cut stem, the best thing to use is a small round file. If you have a chrome steering tube, liquid engineering blue can help to see the cut.

[@zygmuntthecacaokakistocrat6589]

You mean 'steerer tube'. The stem is the forward extension. The best thing to deburr a metal tube is a deburring tool, the best thing for CF is sandpaper.

[@ebikescrapper3925]

My mistake.

[@ACMEpowersports]

Always leave extra steerer. Ride for 6 months and slowly lower as you get in better shape.

[@swites]

Another thing to be aware of, is what type of compression plug/top cap arrangement one has. I just did this job a few days ago. Took 3mm off below where stem sits. But my compression plug arrangement has a 2 to 2.5mm lip which sits on top of the steerer tube to stop compression plug falling into the frame. So now thats reduced the gap from 3mm to less than 1mm. So I should have cut 5mm off instead of 3mm to account for this. Still seems to tighten down alright, but only just!

[@sbccbc7471]

This is why an expander plug's flange thickness must be taken into account.

[@mattbockbrader2140]

Check with the manufacturer first. Some require that you use 3-5mm spacer above the stem.

[@GilbertTang]

Alex, you are excellent at your job and such a cool person. The world is so much better for you in it. Happy new year to you and yours.

[@toozydude2]

The compression plug thing... seems like its not as trivial.. is it not recommended to have the stem clamped at the same location as the compression plug? Then they are both holding the same bit of carbon. Otherwise you have some partially expanding forces from the plug and then compressing forces from the stem. I have seen many with the top step bolt done up where the 2 step sides are touching, because there is no support under it, sometimes even the steerer tube is cut too short. Therefore, i like to always have a spacer above my stem with the compression plug completely overlapping the stem.

[@sbccbc7471]

If you want to play it safe, you can do so. That's why my replacement expander plug is deliberately taller than my stem's stack height. I can still go a little lower without clamping unreinforced steerer tube.

[@jonathansanchez1305]

Sounds more like inferior carbon or over-toruqing

[@SergioCristancho]

Stage 1. get a proper bike fit. Stage 2. ensure that the measure is the proper one ... think about it IF you need room for adaptation. Stage 3. think one night 2 1 week even 1 month... will you have this bike forever? are you saling it 2 or more years from now? if yes... think leave 1 raiser of margin the next bike usser might need some room for bike fit. Stage 4. leave your bike in the hands of a good bike service mechanic that has a lot of experience and knows how to... and has the experience in the cut of the tube properly... * by the way be sure that the tube has the proper mark and leave the measurements as back up check. stage 5. back a few days hours and enjoy a no chimney top hat extra tube

[@blklex250]

i did this on my canyon ultimate last week.. i pulled the brake hose out of the fork without thinking.. my version of this video is 4 hours long

[@striZcepHotograaphy]

Please take your bike to your local shop to let their professional team take care if this for you! Its too easy to mess this up. A lot of helpful tips weren't said in this video that is only gained with a lot of experience. Pay the $50-100 in labor instead of the $500 for a new fork. Support your local bike shop.

[@justinjewell1043]

Fair, I guess, but how is it "easy" to mess this up? You draw a line around the steerer tube and cut there. This really isn't a difficult procedure, assuming you own the tools and/or would like to move away from spending $100 in labor when that money could be better spent on you acquiring your own tools and learning something new. For the average person watching this GCN vid I'm guessing they're fairly knowledgable about bikes and this is all just added knowledge and encouragement. Anyway, good luck with your steerer tube cutting escapades everybody and remember to always measure twice...er...10x (seriously get the measurement right, that's all that matters) and then cut ONCE

[@123moof]

I never deal with hack saws. Carbon steerer: Cheap tile wet saw cuts easily and avoids dust issues. The cuts are also clean everytime. Aluminum and Steel: Tubing cutter that spins round and round makes a very clean cut, and a little filing to soften the outside and debur the inside.

[@litespud]

I’ve cut a number of CF and metal steerers using a standard 32/inch hacksaw. I use a new blade for CF, do it outside and wet down the steerer before and during cutting to keep dust down. Regular hacksaw will do fine for CF if you don’t lean on it and let the blade do the cutting. Metal requires a bit more “lean”. I use an old stem clamped in place as a guide and cut 1-2mm below the scribe mark to give the top cap clearance (don’t like chimneys)

[@lawrencekelly5038]

My favourite trick with doing this is to put an extra spacer under my stem before I mark it, only a small one, then use the stem to mark to line as per the video. This means that when I come to cut the tube with my small margin of error in there, it's a flat line, rather than having to add a few mm to the line from the stem as per the vid. I just find it easier to get it nice & neat this way.

[@eduardocarvalhoneto909]

Awesome background music!!

[@ralfspenneberg2659]

Parktool cf-2 cutting fluid is only recommended for metals? Do you recommend it for carbon as well? I would rather use something like water. #askgntech

[@billkallas1762]

Measure three times, cut once.

[@andrewsutton1657]

why not use a pipe cutter instead of a hacksaw and cutting guide? Really simple to align and next to impossible to cut it at a bad angle. (not needed to do this on cf stems though)

[@BennoSattler]

Potentially fatal on CF tubes.

[@brucedeboer5671]

Better be pretty damn sure your bike position is correct.

[@MrJhockley]

I would advise against this. Get a bike fit 1st and even then injury and ageing will thank you for the extra stack height.

[@Joshuavoice29]

You should still wear a mask or respirator.

[@DrDubstyle]

For all the dust from power tools?

[@demand61]

​@@DrDubstylefor the carbon fiber dust. But feel free to ignore good advice

[@calmprn7165]

Why ?

[@fgoehner]

Because Carbon dust is bad for your lungs

[@JuanAsencio-jc2ms]

Is it true you can cut a carbon fork with a plumbers tube or Pipe Cutter?

[@oliverstevens4689]

Not to be done on carbon forks as apparently causes delaminating of the tube below the cut due to the force of the pipe cutter. Works for alloy and steel tubes only!

[@sbccbc7471]

​@@oliverstevens4689 I think it can't be done anyway. I've tried it on a scrap piece of steerer tube, the rolling elements of the pipe cutter can't even turn.

[@drooghead]

As usual, take GCN's advice with a grain of salt. Leave your steerer tube as is so you can adjust it later on for more comfort. A slammed stem is much more dangerous and uncomfortable than a "chimney". If you want to get lower on the bike just bend your arms.

[@tobynewman121]

Tell that to 'G', he crashed and lost his spleen due to the Chimney...

[@robinseibel7540]

@@tobynewman121 , yeah, tha'ts likely a rare case.

[@drooghead]

@@tobynewman121 Cyclists have no doubt come into contact with many parts of the bike and received significant injuries. The worst and most frequent injuries are from hitting things external to the bike and lowering the stem and using a smaller frame than you need increases the chance of this happening. Most cyclists aren't racers by a massive majority.

[@cophi501]

one more thing worth adding. with carbon forks, there's a MAXIMUM number of spacer height that is considered safe. usually only 30-40mm worth of spacers. anything higher than that is can be add more dangerous torque to the carbon fork. always refer to the fork's user manual.

[@litespud]

Nothing wrong with a slammed stem if that’s the best fit for you. I spend a few months tweaking stem height before cutting, but then I cut it a couple of mm below the scribe line (don’t like chimneys)

[@jn1083]

Did you lose any significant stem clamping engagement by cutting 5mm below scribe mark?

[@michaelmechex]

No. That's how it's intended to be.

[@cypis666]

Scribe mark was slightly above the stem, you need to cut it slightly lower so the top cap can compress on stem instead of fork tube.

[@BennoSattler]

If you want to play CF safe: Do not clamp directly on the edge/end of any tube. Use a LONG compression plug and a small spacer on top of the stem. A 5mm chimney never hurt no one, but saves the integrity of those lay-ups.

[@litespud]

5 mm is excessive. You really only need 1-2 mm*just enough clearance for the drop cap “lip” *assuming the expander plug doesn’t have a top flange- otherwise you need to allow for the flange height

[@zygmuntthecacaokakistocrat6589]

Slamming stems and cutting the steerer below flush with the top of the stem clamp is always a bad idea. As you age, you can't do the head down, bum up attitude any more, and need a bit of verticality at the front end. Good forks are £250 and up (£500 and up for suspension forks) so if you get this wrong, you will be calling yourself an idiot for a long time. Or be called an idiot by the bike's owner.

[@bitgeist_21]

I ALWAYS appreciate videos like this one. I'm getting ready to cut the steer tube on my new (model year 2022 SuperSix EVO frameset which I bought heavily discounted from a very reputable online retailer) fork and I was just about to start looking for "refresher" videos since it's been quite a while since I cut my last steer tube).

[@FelisSilvestrisBE]

In the world of cycling as a hobby I would advice against it: You can't really resell it anymore without telling your buyer they'll need a new carbon fork, which *hopefully* is still being made AND in the same colour. And if you don't sell it, I hope you don't develope back problems and stay flexible; but then again I believe carbon has a "best before" date? All this risk for looks? Seems not a financially concious decision. About the risk of injury: could you kindly point to such instances?

[@sbccbc7471]

Even if the replacement fork is of a different colour, it can always be repainted. Most importantly is to get one with a longer or uncut steerer tube.

[@litespud]

After I “garage doored” my bike and trashed the original CF fork, I spent years looking for a replacement (I fitted a steel fork in the meantime). Although it was long out of production, I finally found an NOS uncut example on eBay - a bike manufacturer used to spec this fork in their builds, but no-one was buying 1 1/8” rim brake forks with a 28mm tire max, so they were clearing out their obsolete fork stock. I got it for ~1/3 the original MSRP 👍

[@Backpacker8381]

#askgcntech Hello. I am replacing the bottom bracket on my Mongoose Envoy cargo bike. The information is CH52-73, 131.5L, BC 1.37 x 24T. I have not found an exact replacement online yet. Is a little variation possible such as getting a bottom bracket that is 127.5L or 140L? How much variation is OK?

[@billcodey1430]

Is there a realistic benefit to cutting the steerer tube beyond appearance?

[@litespud]

Aesthetics matter. Riding around with a big ol’ chimney is like wearing new jeans and not taking the tags off. Doesn’t affect how the jeans work, but looks goofy

[@tomahoks]

Under 5mm is ok.

[@lawrences1347]

It's dangerous in a crash. Your stem should be clamping in the same place as the expander plug not below it. Also weight, if you care about that.

[@apuldram]

Weight 😂

[@iberiksoderblom]

After more than six month, I havent desided what actual height I want for my bike... It goes up and down from time to time. Depends on how I feel, the weather, if I'm riding in the dark... Finding the ideal compromise takes time.

[@litespud]

I spend months tweaking the stem height and living with the final position before I make the final cut. Time well spent, IMO

[@carlobrigante881]

Where’s the final retro restored steel Italian bike video 👀

[@adadinthelifeofacyclist]

If you have to move the compression plug in cf forks it's well worth using cf jointing compound to make sure it grips; worth bearing in mind if you keep getting a loose headset and wondering why it never stays adjusted correctly.

[@sbccbc7471]

Yes, some expander plugs I've worked with don't have as much bite as others, so I do use carbon paste on those.

[@Bazza1968]

The compression plug and top cap are only for adding preload to the bearings. If your headset is becoming loose you are not tightening the stem bolts enough and if it's carbon stem to carbon steerer maybe needs some paste to add friction without having to go beyond specified torque settings...

[@sbccbc7471]

@@Bazza1968 The steerer tube is the only place that doesn't need carbon paste. In fact, it's unadvisable. The particulates could get into the headset assembly and should the bike be involved in an accident that knocks the cockpit about, the bite provided by the carbon paste has a chance of causing the stem to shear the steerer tube.

[@TomDeLombaerde]

Dangerous in case you fall....how?

[@midhc5072]

My advice, don’t. One day you’re fit and agile and suddenly you aren’t after realising you aren’t as young as you think and the bike is no longer comfortable for you.

[@stuartmisfeldt3068]

Also, if you’re not planning on keeping the bike very long, you can resell it easier.

[@billkallas1762]

You might need a higher position, after you turn 80.

[@chrisdelaplante5515]

@@billkallas1762 No, you will be dead before 80.

[@rashedalshamsi7615]

It happened to me, I had surgery and it took me time to come back, almost three months of course, I came back and found that I didn't expect it to happen and it was my worst days on the bike At least don't do it with an expensive frame

[@TheTonicro]

I can't agree more. It's been 3 years since my last ride. Back injury and lack of time. There's no way I can ride my bike. Slammed and -17 stem on bmc teammachine. I try next summer to fit 2mm spacer and standard -6 stem and go for it. Might be OK.

[@oplkfdhgk]

4:47 any cable pull brake fans here? i love mine.😀

[@Jay-hg2ec]

I say leave it sticking out, as you get old (as I have) you will be grateful you can raise the bars back up

[@oplkfdhgk]

why not just get new stem? i got myself a new stem for like 20€ and raised my handlebar like 70mm with it.

[@JamesSmith-qs4hx]

@@oplkfdhgkYou Millennials like wasting money, don't you🤨

[@morlamweb]

@@oplkfdhgk Raising the stem height costs no money if you've left extra height on the sterrer tube.

[@oplkfdhgk]

@@morlamweb yes true.

[@sbccbc7471]

There's a limit on how much of it can stick out, no more than 20 mm worth of it.

[@333wheeler]

The one aspect where the good old quill stem has the upper hand.

[@morlamweb]

Not really, if you're OK with having a bit extra steerer tube length above the stem. He's overplaying the danger here of having a too-long steerer tube. And with a mechanical setup and non-fully-integrated cables, then changing the stem height is as easy as loosening a few bolts and changing the order of spacers, stem, and top cap.

[@apuldram]

Or just go to a good traditional bike shop. Emsworth Cycles (Hants) is mine!

[@fredsirvalo1904]

#askgntech - I was checking my chain for wear today and wondered the following. If we made an assumption that a WT pro uses the same equipment and same maintenance as I do, would the WT pro wear out a chain in less kilometres ridden, on average? Full discloser: I am an average cyclist with above average equipment.

[@sbccbc7471]

Since they ride faster with a higher average power output, their consumables would wear out quicker than ours.

[@fredsirvalo1904]

@@sbccbc7471 That's my assumption, too. W/kg is not linear with kph given a flat, even surface. I assume W/kg has a relationship with wear rate. I assume someone with more than double my FTP would wear their chains on fewer kilometres than myself. The Zero Friction website tests only at 250 watts, so I can't tell what the relationship may be at variable power.

[@Navigator-v9z]

This is pure science once again on GCN and without forgetting the funny way of speaking!ahahah!

[@iberiksoderblom]

Crash risk? No, thats not backed by any evidence. But people getting severely cut by brakedisks are a thing !

[@eirikkristine]

The compression plug is supposed to be where the stem clamps. I take it out when cutting the fork and put it back at the top after cutting

[@fede1275]

It is different on Canyon 1 1/4" steerers, that small bung is there only to compress the bearings and for the top cap bolt to screw in. Other 1 1/8" steerers will have a standard compression plug, to reinforce the steerer where the stem clamps. And when measuring where to cut it needs to be included in the process as the compression plug lip will also be 2mm or so

[@GokkunGuru]

And if you had to remove spacers from below the stem, oh boy, with headset cable routing, it would be more involving.

[@sbccbc7471]

Many such spacers can be split open or in half.

[@buggen819]

I prefer a longer steerer. Easier to change height if I have looong rides where comfort is important or if i want to feel racy i just lower it.

[@sbccbc7471]

Make sure you still have enough reinforced steerer tube to clamp and that there's not more than 20 mm worth of steerer tube sticking out.

[@stephang.5225]

I never noticed that you have the front brake on the right.

[@litespud]

That’s standard setup in the UK

[@stephang.5225]

Okay. Nice to know. Thanks

[@apuldram]

Also puts the front brake (the one that stops you) in your strongest hand (assuming that you’re right handed). This certainly applies to rim brakes, but probably disc too…?

[@litespud]

@@apuldramsince your front brake does most of the actual braking, it makes sense to assign the front brake to your dominant hand - left or right - for the strength *and* control

[@ancientrouleur]

The biggest take away for me from this video is appreciating that Alex has mastered a skill I have completely failed at my entire life- saying the word 'bung' without laughing hysterically

[@fredrickkun]

Where here to make money not lose money you all understand that now

[@ACMEpowersports]

This blows me away that someone (GCN) can’t give a clearer explanation on this. 🤦‍♂️

[@red2lucas]

This is a bike shop one for me. $35. Done.

[@DamnMyNickIsTaken]

What happens if they fuck it up?

[@sbccbc7471]

​@@DamnMyNickIsTaken Exactly, I've seen crooked cuts before.

[@red2lucas]

@@DamnMyNickIsTaken they have to buy you a new one. Plus take it to a decent bike shop.

[@10ktube]

I'm waiting for durianrider to jump in here and then do a video showing how easy it is to do this on a rim brake bike. Where are the DA cranks too? 😂

[@regsmith5972]

Why do you need to reset the star nut on an aluminium tube at the top of the forks. Why not just use a shorter bolt or use a die set to cut more thread and cut down the bolt if needed?

[@sammyVicious]

yeah, this is an LBS thing for me. no thank you.

[@jayare8424]

Good luck selling that bike now, with short length steer tube you now have a higher chance of not re selling that bike , comfort is everything , we are passed the times of slam your stem ..👀🤦🤷

[@BaBaast]

This is why i love my Fairlight Strael 3 😁

[@Handletaken4]

Cut it as short as possible for extra aero!

[@Andy_ATB]

Not everybody is racing (in fact most people aren't).

[@joaoabreu132]

And not everyone​ is super flexible either @@Andy_ATB

[@AndrewBroadbent-dr8wb]

Why is it potentially dangerous in a crash? Probably more dangerous to have bars set too low. Thank you.

[@MooseBoy99]

You could impale yourself on it?

[@andrewsutton1657]

You should see what a raised steerer did to my mates teeth when he came off.. basically punched a circular hole through top and bottom set. Not sure what the difference would have been if it was all flush, but it's enough to put me off and keep it all as flush as possible...

[@ItzMe3224]

No one said to slam the stem, just make it so nothing sticks over the bars

[@daniel_001]

That is so not worth it.

[@jakebrakebill]

I always like watching videos of how to correctly do things to your bike, just to see how far off I am, on just using a hammer and chisel.

[@richardharris8538]

A steerer tube cutting guide is an unnecessary luxury. All I do is mark where to cut, then make a shallow hacksaw cut all the way around the tube, then keep repeating until I've cut right through.

[@fredrickkun]

i never cut at all Or allow any one else to cut If it comes from the factory 🏭 That way leave it be The lines that they put on it doesn’t Say cut it it is designed for proper alignment Way to many people’s destroy there bike and them selves will the helmets are pristine shape That is the difference of reasons why there is so many motorcycles accidents mistakes on alignment’s use the extra tips for lights or radar systems and navigation 🧭

[@sbccbc7471]

Don't go crying if your steerer tube cracks from being clamped without internal reinforcement.