A new take on front suspension tech I am experimenting with which could be a simple bolt on conversion.
Specs:
Fox 36 140mm travel with custom one piece Upright/fork crown.
Girder fork type link suspension with Fox DPS shock giving 53mm travel.
193mm total travel.
This system gives the front wheel two different wheelpaths....the more vertical of the Telefork and a more rearwards wheelpath of the Link suspension....each seperately tunable.
A more dynamic range of change for offset and trail.
This adds a third level of suspension compliance ( first being the tire...then the Telefork..then the link suspension ).
I plan next to fit a BYB Telemetry system to get some real world performance data...if I dont get rubbished for this to much I may post some of it here ...along with some Vids of it in action.
ate those stanchions pressed in or clamped?
This is so awesome, I love experimental stuff.
Did you manually mill the parts or do you have a CNC?
I love exciting new ideas. In principle, this was used in one of the first Whyte FS bikes, although I recognise this is not using a frame that was geometrically designed to accommodate this (and, of course, the suspension and damping were combined in the Whyte).
But, to me, this looks like it might well feel like somehow turning a long 1990’s stem round backwards and by some mechanical miracle sticking the forks, but not the handlebars, way out ahead of the frame.
Perhaps I’ve misunderstood — nothing new there! — but if not then ‘delivery bike’ comes to mind.
Sorry, but I don’t feel too guilty as this is a paid ‘advert’ seeking feedback.
Nice stack bro
Seriously though, good on ya for having a go.
Cool project
looks like a development challenge/set up nightmare
I always find it funny that bikers go deep into the weeds on rear suspension layout but are ok with a pogo stick up front.
This seems cool but VERY complicated to tune properly.
Impressive work! Kinda like the old school AMP Research forks and FOX had a kid…
Id be interested to see data riding with that set up. Not sure if you'd need multiple sensors. Like one measuring the whole travel, then one on the short shock and one on the lower fork?
Ideal would be something on the front axle that could record fore/aft and vertical. Then record the same trails on the same bike with a traditional fork. Not sure such a thing exists, at least not one intended for this use case.
A tight press fit with Loctite retaining compound and 2mm of extra overlap compared to the original crown.
yes manually milled....I reduce some of the work by having the profile of the part waterjet cut from plate...7075
yeah if this setup catchs on it will keep the "how do I " Forums going for years :-)
This adds another dimension to setup possibilities and less compromise in tuning options....in my experience once you have a solid foundation on what it takes to make it work/how it works....its relatively easy.
It will just have a regular travel sensor on the fork and one on the front shock....I have done this before and it is very insightful in to how well this setup can work...stay tuned.
Just because you can do something, doens't mean you should.
If we don't explore things then how will we innovate
Girvin parallel link forks and similar have been tried off and on throughout the years and they proved garbage almost every single time. There are a few motorcycle applications out there I'm aware of. However, those applications are not as weighed conscious and can do it right.
What about just building a long travel girder fork? Would simplify tuning.
This way more sophisticated than just a Girvin/girderfork....its combining the best characteristics of a link and telefork suspension into one....its how they are combined that is the secret sauce....as I previously mentioned it gives two different wheelpaths to the front wheel....think about that for a minute and the implications it gives on force vector sensitivity etc.
Re: my previous post reply.....also this system adds a lot to the basic capability of the front suspension especially in very rough trails..hence setup and tuning isnt as critical for a great setup...But....dial it in and it has the potential to be incredible.
I say this becaue it gives a tuner/rider the option of seperately tuning small/medium bump response and seperately tuning big hit and bottoming control....so there is less compromise and cross talk between the two....its sweet spot can be much wider.
Never said it's a carbon copy of the Girvin. That said, if there was any benefit to off-road bikes outside a telescopic forks, the motor industry would have figured it out years ago. Experiments, outside the box engineering, tankers are what gets us where we need to go. That said, this is a dead end in my eyes. Feel free to invest your time with it.
Can't wait to see thing thing out and about
Ask any suspension guy with half a brain and they will agree that linkage forks can have HUGE benefits, and yes turning them in to a marketable product is a massive hurdle but I think its very much worthwhile that people keep plugging away at the concept. Although this isn't "just" a linkage fork either but it does provide a good way of combining both types
Very well said :-)
Wonderful how someone spends their time and effort making something and people shit on them. Good on ya for trying this! Looks cool.
stupid question - do they compress at the same time, or with different impacts? Does the fork have to bottom out first then the linkage kicks in? Or does it kind of create an area/zone of suspension use, as opposed to linear travel? this concept was talk of the town years ago, when BCD made his two shock bike where each shock would activate based on different forces.
The motor industry didn't work out 90% of the tech in MTB's we ride today. Why would we use them as a benchmark for what's possible.
Anyway I think it's absolutely rad to see DIY innovation, and I love this hybrid fork. Can't wait to see it progress. There's no reason to wait for innovation from the big brands, just look at Frameworks.
Heres a Vid of a downhill bike I built a few years ago....this is a different type of dual suspension but the concept is the same....the bike is beng ridden through a gnarly rock garden and the 200mm Ohlins dual crown forks are working nicely...setup for plushness right through the stroke as bottoming control is now on the secondary suspension which gives an additional 75mm travel.....so 275mm total.
Note the secondary suspension links at the top of the picture is moving also as the Telefork is moving....the level of plushness and control has to be felt to be believed and as a result the bikes forward momentum through succesive rocks is better preserved.
https://youtu.be/93iEL3b3E68?si=VkIAn7KX86dnnhPC
A few more Pics to wet peoples appetite :-)
How does the effective head angle develop throughout the travel of the shock?
Man. Good on you for the experiment, but I have so many questions.
Not about what you’re trying to do, but how I’d even manage to ride something like this. Trying to dial in two separate air chambers with volume spacers and pressure, etc. Then the multiple compression and rebound settings? I know for a fact I wouldn’t be able to wrap my head around that shit.
Also having two different wheel paths on the front of the bike? The traction-geometry changes and weight transfer dynamics make my head spin.
I won’t make the Proflex comparison like I did in the other thread. If we are comparing linkage forks, I guess I see some benefits over a Trust but not when it comes to adjustments and maintenance.
Good luck in your adventure, and don’t let curmudgeons like me bring you down.
This is the key question about the geo.
Looking at the vids on the builders’ YouTube site for a similar, but definitely not identical product for an Enduro style motorbike, you can start to see the complexity of the arc that the front axle will travel.
I hope the builder replies to you as this is the best question here to date.
My take is that the head angle steepens as the shock at the headset compresses. So, at full compression of the fork and the shock/damper, the bottom bracket is lower (as always with a front fork) and the axle is proportionately higher.
But the key point you ask about is that the wheelbase is visibly shortened which is why it looks to me like the head angle steepens.
On the motorbike vids (with a somewhat different arrangement) this is clearly seen and it would be interesting to hear how that effects handling, especially immediately rolling over an obstruction after a bigger hit. For example, after more significant ‘drops’, a hole often develops immediately in front of where most riders’ front wheel lands (several reasons for that).
I’m interested to hear how this suspension deals with such holes during major compression of the system. Another example would be encountering a sharp-edged rock or shelf at the point of full or near full compression of the system.
We enjoy slacker front-ends these days as it mitigates rowdiness when the going gets rough, as compared to the more upright geo used in ‘the old days’. The sense that in the steps especially that the bike will roll over stuff with a slacker angle — and which a 29” front also helps with.
I see a risk this will hang up more than one would find with a correctly set up ordinary fork offering the same overall travel (using the same frame, obvz). The drop in the bb will be roughly the same. So, it is front to back movement, not up and down movement that is my concern.
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