10 Common Mistakes Made When Replacing A Mountain Bike Fork | How To Fit A New Fork

From cutting the steerer tube too short to using a track pump to set the pressure; there are a few common mistakes that can be made when fitting a new set of forks. Heres Doddy showing you how to avoid them 🔧

When did you last upgrade your forks?

Watch more on GMBN Tech...

🎵 Music - licensed by Epidemic Sound
JuiceBox - Dylan Sitts
Just My Luck - Mattias Hedbom
Midnight Vibe - Yomoti
Motor Town - Da Tooby

Submit your content here:

Brought to you by the world’s largest mountain bike channel, the Global Mountain Bike Network (GMBN), GMBN Tech goes deeper into the bikes, kit and technology stories that help fuel your rides.

Our mission is to help you discover, dial-in and get the best from the latest cutting edge bikes and technology available.

With news and rumours, first ride exclusives, how-tos, the weekly GMBN Tech Show wrapping up and showcasing the week’s biggest tech stories, and more besides, if it’s off-road tech, it’s in.

Every week, of every month we seek out, showcase, and ride the newest gear and innovations from across the globe in an authoritative, inspiring and entertaining way to help you get the best from your rides. And when we’re not riding, we get geeky in an accessible, easy-to-understand way about forks. And shocks. And more to help you setup and maintain your bikes perfectly.

Engage with us every week on the channel and across social media – we’re here to answer every question you’ve got on mountain biking tech.

[glenvaal]

Great video. Especially the bit about not cutting the steered tube too short. My tip, before cutting, compare the length of your old fork to the proposed length, if the latter is shorter, something's not right! I'm my case, I forgot to accommodate the handlebars....really stupid I know, but thank goodness I remembered "measure twice...."

[GlidingTobster]

I diligently followed your recommendation not to use the old tube as a measurement datum.
Instead I measured the crown spacers; three times, to be absolutely sure.
I then cleanly cut the tube with a pipe cutter.
...And then remembered that the handlebar stem is supposed to go on as well 🤦‍♂️

[mtbboy]

another mistake with Star Nut, is to install it on a carbon steerer tube, only compression plugs can be used on carbon steerers.

[herculesmclovin]

Re: star nut; use the topcap.
Once you hammer it 2mm in, unscrew the bolt and fit the topcap in, rescrew the bolt back in, hold the topcap in place and start hammering again. Not magical but certainly helps a little 👍

[Dan_]

An adjustable pipe cutter from the plumbers merchant is better than using a hacksaw to cut your steerer tube, plus you don't get burr at the cut 👍🏻

[FalcoBikes]

Tip on lining up the stem angle: place the bike over some floor tiles, and use the square seams between tiles as reference.

[Ricochetmex]

No thanks, I’ve already watch enough Sam Pilgrim videos, and he is a pro...

[BarryJTaylor]

I recently put 180mm bombers on my 150mm Trance. Best move I ever made. Fixed the low bb and slackened off the head. What a weapon now. I cant see a use for anything under 160 now lol.

PS. I used Sam pilgrims vid as an example of what not to do.

[newttella]

If you buy your own forks, listen to Doddy. If you get free forks, listen to Sam Pilgrim.

[JOE-huqk]

'Filing streerer tube'
Sam pilgrim: a pavement will do

[martinjflanagan]

I use a ruler for aligning the handlebars, gently lay it across the fork stanchions and eyeball the handlebar with the ruler.

[desmond]

Thank you so much for making this video so easy to follow and understand. Looking forward to rebuilding my bike of 20 years old ( sentimental value).

[MPH]

From experience I can say always use a hacksaw and get yourself a cutting guide from park tools or x-tools. As long as you don't screw up the measurements you can not do wrong using those 2 tools. 4:35 After spending a few hundred quid on some forks £20-£30 for a guide is always justifiable when the consequences for screwing up are so high. Sure you can go to the the LBS but they will charge you more than £30 to install some forks.


5:24 A dremel on the lowest speed with the grinding bit inserted also works. Just don't press very hard at all and dab it on to the surface, only making contact for a tiny fraction of a second each time. Works fine. Also works great at getting surface rust of cast steel steerers.


6:30 I lay mine out flat on a work surface with the part i'm working hanging off the end. So the filings/shavings can only end up on the floor.

[j_white]

Perfect video to pair with your How-to video, I'm glad I found it. Thanks!

[mtbboy]

3:02 I also recommend using lube, so the saw can move smoother, the particles don't fly everywhere.
also having fork in a repair stand, and cutting using a saw, is a good idea, this way things don't go anywhere near the seals.

[timndel]

The best way for most of us, is to have a knowledgeable and experienced bike mechanic do it. That will remove the idiot factor.

[MrJakeepooh]

Doddy, my brother, I freaking love your videos! I just have a small quibble with this one. You got me all excited to learn the best way to install the star nut if you don't have the specific tool, but you just showed how not to do it? Did I miss something?

[matteobettola]

Guys there was an even easier way to fit the star nut!
Just use a suuper long screwdriver that fits inside the thread of the starnut itself and start hammering!
Love the channel, got me into mountain biking!

[stiingya]

Good tips! when you use a stem as your cutting "guide" if you put a spacer on it you can keep from scratching up the stem. Plus the spacerr "spins" as you cut and works well. (still gets all scratched up and you won't want to use it again! :)

[geraldmaybebaby]

Please make a vid on fork purchasing errors.
Variations in steelers, tapered, etc.
Extra costs of compatible headsets.
Whether fork travel suits frame geometry, etc.
I have an old marin quad Tara.
And an adjustable travel fork to match the rear travel adjust is a perfect match.