Fox Manufacturing unit has filed a patent titled “Strategies And Equipment For Lubricating Suspension Parts” detailing the usage of bushing-housed ball bearings coupled to a self-lubrication system. The patent provides us some perception into how Fox’s long-travel mountain bike forks such because the 36, 38, and 40 might evolve sooner or later, with the innovations described working to cut back binding at ever-slacker head angles, whereas additionally constantly lubricating the wiper seals throughout use.
Tucked away inside that exact same patent doc is an outline of a coil sprung fork, travel-adjustable over its full 80-125mm vary, indicating the potential of a brand new XC/Downcountry fork on the Horizon from Fox, or extra probably their sister-brand, Marzocchi.
Photos tailored by Cory Benson
Fox Self-Lubricating Fork
This newest patent from Fox (US 11566682 B2) describes what we think about to be the interior workings of the decrease leg channels that may be seen on the Fox 38 suspension fork. Principally, a reservoir of lubrication oil sits in a reservoir located within the decrease leg, and that oil is pressured right into a “fluid conduit”, or channel, when the fork is pushed into compression. The channel sends that lubrication oil up the leg to the wiper seal area, dropping it again into, or close by the froth ring.
This self-lubricating system works to make sure the froth ring is at all times saturated with lubrication oil, such that the wiper seal and the fork’s stanchions stay lubricated throughout use. That will assist maintain your suspension fork feeling easy off the highest of its journey. A test valve that includes a spring-backed ball bearing, pictured round half manner up the fluid conduit, ensures that oil can solely journey in a single path via the channel.
The patent then describes a bushing inside the decrease leg that options cup, lip, or chevron seals that enable lubricating oil to journey again down into the reservoir. The system is designed to repeatedly cycle the oil as much as the froth rings throughout regular use of the fork.
Fox Fork Sliding on Large Ball-Bearing Bushings
What’s possibly most attention-grabbing about this Fox patent is the embodiment that features use of ball bearing bushings. Whereas conventional bushings will be described as stable, low-friction rings… these bushings described right here use “linear movement bearings”.
The thought right here is to remove the undesirable results of bushing binding. Principally, when a fork compresses, it’s topic not solely to forces working instantly via the telescopic aircraft, but additionally forces which can be wherever between parallel and perpendicular to that. Such forces may cause the bushing to stay or bind, which may stop the fork from working easily. These linear movement bearings are described as as much as 6 circuits of ball bearings positioned on the within floor of the bushing, which ought to enable the fork to telescope extra freely with diminished friction induced by side-loading.
Right here’s how the patent doc describes it:
“In use, a suspension fork is usually positioned in a bicycle or bike at a rake angle. Extra particularly, the steering tube (and therefore the fork) is connected to the car at an angle from the vertical (e.g. rake), versus absolute vertical, to allow improved car dealing with. An artifact of that angle is that the load of the car (and related impulse load on account of affect) bearing on the entrance wheel imparts not solely compressive but additionally bending masses into the entrance fork and its legs. Such bending masses improve the relative sliding resistance between, for instance, the higher leg tube and the decrease leg tube (by rising the conventional/radial load on, for instance a facet of the bushing). A bonus of linear movement bearings is decreased obvious friction between [the] higher leg tube and [the] decrease leg tube on account of decreased friction between the higher leg tube and the inside of the bushing. Such decreased friction permits the suspension to maneuver extra freely, and higher take up shock regardless of the tube facet loading incident to the rake angle”.
Sounds smart, proper?
Now, check out the tables beside the drawings of the bushings. That implies that such a bushing can be 3.0″ in diameter. That’s so much wider than the decrease legs of forks which can be generally in use right now. No less than on bicycles, anyway. The final time we noticed a fork made for mountain biking that was wherever close to that chunky? The Cannondale Lefty Tremendous Max Carbon PBR, maybe. That single-sided fork used a hybrid needle bearing system that, equally, claimed to end in a smoother fork than conventional designs.
Possible, the scale of those ball bearing bushings would want to return down a good bit earlier than they may very well be efficiently carried out. Nonetheless, if Fox had been to make use of them instead of a plastic bush, we might see fork lowers develop significantly, with general fork weight closely impacted, too. That mentioned, the rider of a 30kg eMTB will not be too bothered in regards to the added weight, particularly if efficiency is considerably enhanced.
One other rationalization is that Fox is hiding expertise meant for a bike inside a patent that appears to be centered on bicycles. Who is aware of?
Rightly so, it’s possible you’ll marvel in regards to the sturdiness of such a design. The design from Fox doesn’t ignore this: “a floor hardness remedy is utilized to an exterior of the fork leg participating such a ball kind bearing to cut back the impact of excessive localized bearing stress on contacted parts of the fork leg”.
In a single embodiment, the Fork patent describes the usage of the linear movement bearings together with the self-lubricating system. Therein, the bushings additionally function gaps positioned periodically round their circumference to permit fluid to movement again downwards into the reservoir.
Is a Quick-Journey Coil-Sprung Marzocchi Fork with Adjustable Journey on the Horizon?
Elsewhere inside the most recent patent from Fox (US 11566682 B2) is the outline of a travel-adjustable coil-sprung fork. Journey will be adjusted over a variety of 80mm to 125mm by positioning one or two spacers both above or beneath the coil spring, very like we see on the Marzocchi Bomber Z1. A kind of spacers is 25mm tall, whereas the opposite is 20mm tall, indicating that doable journey lengths are 80mm, 100mm, and 125mm. With small journey numbers, such a fork would probably be geared toward XC or, provided that the load is unlikely to be competitively low, Downcountry.
For now, it’s a “no remark” from Fox on all the above.
They did admit to some new, longer light-weight dropper posts right now, although…
