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I've recently bought a new frame and having never built a bike up before I didn't realise the forks would come uncut.
I really have no idea where to start with the job and it's stopping me from working on the rest of the bike (cable routing etc) any help greatly appreciated.
Measure many times!!
When I’ve cut one in the past I’ve used an old stem as a guide, put masking tape on the steerer with a line drawn to show where to cut and used a new fine hacksaw blade. Best to cut outside so you have less chance of breathing in carbon dust and file the cut end smooth and the run some superglue over the cut surface to prevent flaking. And measure many times!
Or pay a bike shop to do it.
I tend to leave them a bit long for 1st cut so you can place a few stem spacers and play around with stack height. You can then cut your steerer again or just leave the spacers on top of the stem.
For a carbon steerer, you need to cut using a fine hacksaw blade and wear a dust mask!
You also need an 'expansion bung' or 'expansion nut' for carbon steerers, the longer the better and some carbon friction paste to fit it. DO NOT USE A STAR FANGLED NUT!!
Also only torque steerer bung and stem bolts to whatever torque it states on them.
Get a Tungsten Carbide sawblade, about £3 from Screwfix, less dust, a cleaner cut and doesn't splinter as you get to the end. If it has to be metal then at least 32t per inch and use masking tape. Obviously, as above measure twice!
You will die if you cut carbon fibre. It is well known to be instantly toxic to every living thing within a 15 mile radius. You will find an exclusion zone bigger than Chernobyl round your workbench. Even thinking about cutting it will bring down the wrath of the Elfin Safety milennials.
Do us all a favour and buy some forks with a shorter steerer.
But not quite as bad as a banana skin then?
I ended up measuring 13 times, cutting. Little bit off the end to practice and then going for the full cut whilst holding it in the jaws of my bike stand....
Feel free to call me a cowboy 🤠
Also neglected to wear a dust mask because carbon fibre lungs sound pretty robust.(I'm not allowed to use them in work as I'm not tested or something so I didn't have one available to 'borrow'.
Seems to fit fine my only concern is that the bearings don't seem to be pressing together and holding the steerer in place. Is that normal? I'm afraid of torquing it up to far as my calibrated arm doesn't do 5nm.
Seems to fit fine my only concern is that the bearings don’t seem to be pressing together and holding the steerer in place
Do you mean the fork is dropping out without a stem on? If so then that is normal. Or that you can't compress the stem down with the fork bung to stop any play? Or something else
For carbon steerers you need to add a 5 mm spacer above the stem. This needs to be factored in before you cut it, obviously. It avoids crushing the steerer with the stem clamp. It will also provide some clearance for the preloading top cap ) normally these are not flush underneath) which is probably why you are unable to preload the bearings properly now you have cut the steerer.
Do you mean the fork is dropping out without a stem on?
Yes that's what I was worrying about. My previous fork didn't have sealed bearings they were the ring assembly type and everything seemed to be pressed in and then the fork was held in place with the compressions ring on top of the top bearing.
I cut and assembled with all the spacers I had as I wanted to have the bars as high as possible so I may try putting the 5mm on top like TiRed suggested. It does seem nice and solid though and im.awaitijg a few more parts before I can get it test ridden.
I assume you've fitted the crown race to the bottom of steerer before installing the forks into the frame?