I think I know the answer to this but I’m hoping there’s a smart solution I don’t know about.

I want to pop p-clips onto tapered fork blades to mount a front rack. The rack stay will force the clip down and the fork blade is a round tapered tube, around 22mm OD at that point with a gradual taper. A thin, hard rubber strip under the lower part of a Tubus p-clip might do it but it’s a bodge.

Any bright ideas?

Will the structure of the front rack not hold the p clip up assuming the bottom of the rack is actually screwed into something?

A cheap and cheerful option is to wrap a load of insulation tape around the fork leg just under the p-clip, enough to create a bulge that it can’t slide past. Looks ugly but I did it on my fat bike and the rack never slipped down in 2+ years of riding.

https://www.onbuy.com/gb/minoura-mt-4000sf-front-pannier-rack-for-mountain-bikes~c13070~p68163694/

These Tubus adapters look to have enough material to file a bit off with a round file to match the fork profile.

https://www.spacycles.co.uk/m5b0s215p2031/TUBUS-LM-1-Mounting-Set-T72100

Do you happen to know anyone with access to a 3D printer?
A bit of trial and error could make you a two-piece sleeve with a taper inside to match the fork leg and parallel dia outside, held together with a couple of small nuts & bolts. Done properly it could look quite slick.

I would use rubber lined P clips.

As leffeboy says, assuming there are eyelets at the drop out then the upper mounts have no significant vertical load so ought to stay put. I’m sure there are many folk running about with racks held in place entirely on p-clips, but the thought of a loaded rack dropping onto a front wheel at any sort of speed would be enough to send me running to the shop for a suitable fork.

Mtbfix, leffeboy – it’s a mid blade mount rack support leg. Got one eyelet at the dropout that has a guard attached. So a longer support is one possible fix. If it should ever slip the guard is between the tyre and rack platform and I was going to add a back up cord loop between bar and the rear platform to help limit any slip.

Bullandbladder, I was looking for a tapered sleeve of sorts to do that for a good p clip. It’s under a mm of taper over the area of a clip so some careful gaffer tape use might do it, combined with good rubberised p clips.

Flaming fatality coming up.

I would use rubber lined P clips.

Ditto.

Wondering if a hose clip might be more secure. Depends whether a p clip or a hose clip might take to a slight taper better. The eyelet of the rack support foot could fit via the clip’s bolt. Covering the hose clip strap part with heat shrink first and putting a tapered wrap of gaffer tape on the blade of it to sit half on, and limit slippage as steezysix mentioned.
P clip likely to look neater though.

I would use rubber lined P clips.

This.

I haven’t tried it on a front fork but I’ve been running rubber-lined P-clips mounted on my seatstays to mount my rear rack for a couple of years without issue.

Maybe a piece of rubber with a hose clamp mounted underneath the P-clip for a belt and braces approach given the taper and steeper angle of forks.

You could also put a support strut from the dropout eylet to the p clip for belt and braces

drill and cage nut?

Yeah drilling the blade and fitting a rivnut might be the more pro fix, want to be sure the rack is useful before going that far. Would prob be best to get a barrel eyelet brazed onto the front edge.

Could you not tie a short piece of ~3mm rope around the fork, then either put some heatshirink or tape over it? Might just be enough to stop it sliding down.

Cut and stretch over the fork leg a couple of pieces of inner tube – sounds like a ruined road bike sized inner to me. By that I mean a donut/ring of tube not a flat sheet of it.

Build up a couple of layers and then when you tighten the p-clip you should not only have some compression of the rubber at the fat/top end that allows the less compressed thinner bottom end to grip but also the added friction of the rubber.

Don’t load it up with a massive weight and I’d have thought it would hold reliably.

I have not tried this but I would if I needed to do what you do.

Could you adapt a Rixen and Kaul clamp? They fix a narrow stainless steel band and give a very firm fix. Maybe a couple of these or similar:
https://www.sjscycles.co.uk/lighting-spares/rixen-kaul-minimount-for-fitting-light-or-reflector/
Might be a bit neater than jubilee clips.

That Rixen Kaul clamp is a good idea. I have some rubberised P-clips on order and might also try the R+Ks, they’d be useful for other things anyway. Will add to the next SJS order.

+1 for the comments on a band of inner tube or similar, I used gaffer tape in that way to support a light mounted to a Cateye reflector bracket on the same fork blade before.

rubberised clip on top of a “wedge” of duct tape, here

… so definitely don’t do that