[EVRAC]

Built for my mech. eng. degree final project last year. Just got it assembled and tested for the first time.

7" Travel. Almost perfectly linear wheelpath, exactly like a normal fork, with standard rake and trail geometry.

Nice rising rate, floating shock arrangement.

Very stiff front-to-back, and torsionally.

Very smooth motion due to bearings throughout.

Weighs a tonne though.

Successful first prototype. Not sure if I'll bother with a second. Fun project.

https://picasaweb.google.com/101728978993585111636/Frankenfork?authkey=Gv1sRgCI6KqbPsh4XbyAE&feat=directlink

 

[UiUiUiUi]

holy sh!t it IS ugly, but oh well awesome project!

used to have a girvin fork back in 95
but yours reminds me of the para forks

have a look
they still exist

http://www.parafork.com/

 

[Pslide]

Awesome man, well done!

Having ridden it, do you think there is any merit in the design if it could be made at a competitive weight?

(I also had a few Girvins in my day...)

 

[Sandwich]

Looks amazing dude. Any compensation for brake effect? Any ideas on how to lighten her up? How does it steer?

 

[Manifesto]

if i see this at burke youve got to let me try er out!

 

[Huck Banzai]

fear and loathing!! lol, but who knows! Nice project, probably the only fork other than an Avy heavier than my 888.

 

[EVRAC]

if i see this at burke youve got to let me try er out!

Ha! The test ride was at Burke! Did Overtime Braap Hustler. Now I need some rougher trails.

Do I know you?

 

[EVRAC]

Looks amazing dude. Any compensation for brake effect? Any ideas on how to lighten her up? How does it steer?

Seems fairly neutral on brake induced front end compression.
Lots of ideas for weight savings. There is just way too much metal in there. Every web and edge could be half as thick. Maybe carbon legs?
Steering precision is excellent. The extra mass is out quite a way from the center of steering rotation, so you do feel the extra rotational inertia resisting steering input.

 

[EVRAC]

holy sh!t it IS ugly, but oh well awesome project!

used to have a girvin fork back in 95
but yours reminds me of the para forks

have a look
they still exist

http://www.parafork.com/

Yes I contacted Parafork for more info. They even had a model of a downhill/freeride version that they never produced.

 

[IH8Rice]

Maybe carbon legs?

theres a couple of custom choppers with similar front suspension designs made out of carbon

 

[Manifesto]

Ha! The test ride was at Burke! Did Overtime Braap Hustler. Now I need some rougher trails.

Do I know you?

shweeeet!
i'm just some random from the internet

 

[tacubaya]

Built for my mech. eng. degree final project last year. Just got it assembled and tested for the first time.

7" Travel. Almost perfectly linear wheelpath, exactly like a normal fork, with standard rake and trail geometry.

Nice rising rate, floating shock arrangement.

Very stiff front-to-back, and torsionally.

Very smooth motion due to bearings throughout.

Weighs a tonne though.

Successful first prototype. Not sure if I'll bother with a second. Fun project.

https://picasaweb.google.com/101728978993585111636/Frankenfork?authkey=Gv1sRgCI6KqbPsh4XbyAE&feat=directlink

 

[Honus]

Aww- you should have gone all out and built a Ribi fork.

 

[frango]

I'd call id Triple Maxle instead od Triple Clamp

 

[slimshady]

Aww- you should have gone all out and built a Ribi fork.

Is the company who made that THING somehow related to Brodie? Holy linkages batman!

 

[LOOnatic]

Far out man i think for a 1st proto its looks great

 

[marshalolson]

that is an awesome school project. check out the old school look fourneles, the ultra pimp version of the original AMP fork.

 

[Honus]

Is the company who made that THING somehow related to Brodie? Holy linkages batman!

I don't believe Brodie ever had anything to do with Honda's racing department.

 

[xy9ine]

I don't believe Brodie ever had anything to do with Honda's racing department.

nor does / did brodie build crazy-link bikes. i scratch my head.

oh, and rad work on that fork! still waiting for you to develop a mad gearbox bike...

 

[Vrock]

That's ****ing awesome!!!!!!!!!!!!

 

[EVRAC]

that is an awesome school project. check out the old school look fourneles, the ultra pimp version of the original AMP fork.

The Look and Parafork were definitely inspirations for the project. Those are some better pictures of it than I had seen before. Nice.

 

[EVRAC]

nor does / did brodie build crazy-link bikes. i scratch my head.

oh, and rad work on that fork! still waiting for you to develop a mad gearbox bike...

I had a complete solid model of a new gearbox and frame, but I've dropped it in favor of just buying a Zerode.

My next projects are a few custom shop tools and maybe another version of the pedals.

 

[LMC]

I had a complete solid model of a new gearbox and frame, but I've dropped it in favor of just buying a Zerode.

My next projects are a few custom shop tools and maybe another version of the pedals.

a gearbox of your own design or a g-boxx frame?

can you post pics of this?

 

[monkeyfcuker]

That's sweet man, good work! What's the axle to crown height out of interest? I'd also be really interested in seeing your frame design.

 

[marshalolson]

I had a complete solid model of a new gearbox and frame, but I've dropped it in favor of just buying a Zerode.

My next projects are a few custom shop tools and maybe another version of the pedals.

awesome man. really cool project. what leverage ratio did you plug into that fork?

2.5" -> 8" ?

 

[EVRAC]

awesome man. really cool project. what leverage ratio did you plug into that fork?

2.5" -> 8" ?

The leverage ratio is about 2.7:1 in the first inch of travel, and rises to 2:1 in the last. 7" total travel.

 

[Arkayne]

 

[EVRAC]

a gearbox of your own design or a g-boxx frame?

can you post pics of this?

Full custom gearbox and frame.
I'll try to grab some screenshots.

 

[marshalolson]

how about a 6-7 speed planetary hub that is 150x12mm, disc compatible, and not stupid heavy.

come on man. get on it

 

[buildyourown]

I have long thought that this style of fork integrated into the frame design would be the wholly grail of stiffness and weight. The only reason is hasn't existed for a DH bike is it requires one company to build the frame/fork from the ground up. Still surprised Spec or Cannondale haven't tried it.

Nice work.

 

[SuspectDevice]

I have long thought that this style of fork integrated into the frame design would be the wholly grail of stiffness and weight. The only reason is hasn't existed for a DH bike is it requires one company to build the frame/fork from the ground up. Still surprised Spec or Cannondale haven't tried it.

Nice work.

 

[NoUseForAName]

I don`t know why it took this long for a picture of a tubby Brit on board one of those Marin/Whytes to be in this thread.

 

[eatmyshorts]

Its amazing how much time everyone debates how much/how little brake feedback there is through the back of a dual suspension mountain bike. No one really looks at the front..

Having a 64/71 deg head angle, with the suspension fork following close to that angle for a wheel path certainly encourages a lot of brake dive.. not to mention the mechanical friction of the rotational load applied through the lowers on the stanchions under braking..

 

[Steve M]

EVRAC - f**king rad. Really, really awesome.

Its amazing how much time everyone debates how much/how little brake feedback there is through the back of a dual suspension mountain bike. No one really looks at the front..

Having a 64/71 deg head angle, with the suspension fork following close to that angle for a wheel path certainly encourages a lot of brake dive.. not to mention the mechanical friction of the rotational load applied through the lowers on the stanchions under braking..

Agreed, however people are all used to the identical dive characteristic, axle path and steering geometry that you get with ANY model telescopic fork. Given how hard it is for the companies out there to get it right when axle path and steering geometry are fully constrained, introducing more variables would require so much R&D to get right that most companies just aren't willing to touch it. Linkage DC forks also have the issue of being unable to compensate for changing headtube stack heights, and leading link forks in fact generate MORE dive under brakes than telescopics.

I think there is definitely potential for a linkage fork to be built that makes good use of anti-dive characteristics and the ability to change the shock rate without messing the axle path or steering geometry though.

 

[eatmyshorts]

Agreed too.. Considering how long it has taken manufactures to get it right with rear suspension... Would be very interesting see the circus act if everyone jumped on the linkage fork bandwagon..

 

[fluider]

I think the suspension kinematics has been well explored over the past few decades. So, for suspension designers it shouldn't play some significant role.
I'd be much concerned about customers' (anti-)attitude ...

 

[yuroshek]

 

[Sandwich]

haha, shall we revisit the RM "open-source" linkage fork? I was just perusing that thread recently.

I still really want to make a small floating brake for a fork. I think that would be massively fun to experiment with.

 

[Steve M]

haha, shall we revisit the RM "open-source" linkage fork? I was just perusing that thread recently.

I still really want to make a small floating brake for a fork. I think that would be massively fun to experiment with.

haha, I have more than just a few ideas if anybody anywhere wants to volunteer manufacturing time... may or may not have been running numbers for the past 18 months

 

[Sandwich]

do you have a concept for a brake bar or linkage fork? The complete fork would be impressive but a massive challenge...I've been tossing around the idea of a mount-able brake bar for common forks, something that would just bolt on then attach above the crown. The problem is skirting the lowers, but I haven't really tried that hard. Should be easy on a dorado or other inverted fork.