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NAHBS 2015: Funk Cycles’ 20 lb Titanium Full Suspension La Ruta 29er, Plus Colorful Ti Anodizing

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Funk Titanium coombe pedals  (7)

Likely one of the most performance oriented mountain bikes you could find at NAHBS, Funk Cycles’ sharp La Ruta build was also one of the lightest. That is, at least when it comes to full suspension. Certainly one of the very few full suspension bikes at the show anywhere near 20 lbs, the La Ruta also features some incredible detail work including custom anodized graphics. The Funk team might not have gone home with any awards from the show, but they clearly demonstrated their ability to build incredible titanium bikes…

Funk Titanium coombe pedals  (2)

It might not look like it from the onset, but that is a 20 lb titanium full suspension bicycle. Funk points out that they could have gone even lighter with parts like a carbon seat post but they wanted to build a bike that was to their liking and 100% shreddable. Built by hand in the front range of Colorado, each Funk is crafted from seamless, cold worked and stress relieved titanium – in this case, 3AL/2.5V tubing and 6AL/4V for the flex plate.

 

Funk Titanium coombe pedals  (8)

Funk Titanium coombe pedals  (9) Funk Titanium coombe pedals  (21)

That carefully machined flex plate and flex points at the seat stays allows for 80mm of pivotless, bushingless suspension travel and sub-20 lb builds. Built with simplicity and durability in mind, the frame comes in at 4.5 lbs for a medium with shock. Built with Paragon dropouts, the 142×12 thru axle build shown here is optional.

Funk Titanium coombe pedals  (14) Funk Titanium coombe pedals  (6)

Funk Titanium coombe pedals  (15) Funk Titanium coombe pedals  (10)

Displaying the finish work of Dan Harvey, the La Ruta also takes titanium finishing to the next level. One of the few companies experimenting with titanium anodizing, Dan used his background in physics to figure out what was actually going on at the surface to allow for these custom finishes. According to Dan, anodizing titanium creates a layer of oxidation and it’s the thickness of that layer that determines the color. That means that the stronger the voltage that is applied through the liquid electrolyte, the thicker the layer. Colors start off as a bronze color and then change over to purple and then to blue as the voltages is increased. In order to anodize smaller sections of the frame, Dan uses an electrified paint brush of sorts that allows him to spot anodize sections and then mask off the designs so they can be blasted to make the final shape.

Those paw prints on the top tube? Those are recreations of the actual muddy prints Dan’s dog left through his kitchen. Good dog? The anodizing even extends to the titanium spring found on the XX1 rear derailleur.

Funk Titanium coombe pedals  (18) Funk Titanium coombe pedals  (22)

To help get he build to 20 lbs this La Ruta rolls on Kappius wheels and carbon rotors.

Funk Titanium coombe pedals  (26)

Funk Titanium coombe pedals  (1) Funk Titanium coombe pedals  (27)

Funk also had their new Curtana cyclocross bike on hand which features a completely anodized frame rather than anodized graphics. Built with adjustable vertical dropouts, the Curtana looks like a dialed Ti cross bike for single speed or CX1 use.

funkcycles.com

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andre
andre
7 years ago

too much drooling here!

1luvrasta
1luvrasta
7 years ago

I always liked his craftsmanship going back to when Funk was producing elevated chainstay frames in the early 90’s.

craigsj
craigsj
7 years ago

Remarkably light but also one of the poorest pedaling FS bikes you’ll find, and with the carbon rotors certainly one of the poorest braking. Despite their claims otherwise, this is a weight weenie build. It would be best shredded in a chipper. It’s pretty though.

It’s a shame that NOT ONE Ti manufacturer that builds flex plate designs has figured out that the plate needs to be elevated off the BB. I even tried to get James at Black Sheep to do one custom for me but could never get him to start the project.

I personally think Ti flex plates are great solutions for FS but it doesn’t mean you can ignore suspension kinematics. Custom builders are NOT suspension designers.

M.C. Slammer
M.C. Slammer
7 years ago

Firefly and No.22 have some sweet anodized frames, and I have been a fan of Funk for years. I have always thought anodizing looked great and would love to make it part of my custom build. However advice I have received from builders I have contacted have made me think twice about this option. From Seven Cycles website:

“A small number of manufactures offer anodizing as a way of decorating the surface of titanium frames (or components). Basically, the process creates a dense, colorful film of titanium oxide, which adheres to the frame’s surface. Ironically, this is the same type of oxidation that any skilled titanium welder will prevent at all costs, because it will cause the weld joint to become extremely brittle. (This is why Seven’s expert welders bathe both the inside and outside of a titanium frame’s weld joints in an inert gas, thereby protecting the molten metal from the high levels of nitrogen and oxygen that naturally occur in the environment.)

The titanium oxide film created by anodizing is, thus, extremely brittle, so the frame’s surface cannot flex as it would during normal use. Cracks form through the anodized shell, which will eventually propagate into the tube wall, ultimately causing frame failure.

Seven strongly advises against anodizing titanium. Hence, we will void the lifetime warranty on any Seven frame that has been anodized”.

What do all the BR experts have to add?

Ligero
7 years ago

M.C. Slammer, I will add my 2 cents even though I am not a BR expert. What Seven says about the layer being more brittle than the regular surface is true but when they say “which will eventually propagate into the tube wall, ultimately causing frame failure” it should say ‘may eventually”. This is a case of something on paper not matching up to what works in the real world. Titanium bolts have been anozized for years and there seems to be no difference in longevity over those and regular titanium bolts. Having worked for a large titanium company I have seen many things that were supposed to be really bad practice with titanium work just fine and not have any failures.

So on paper it could be bad but in the real world it is no problem.

Martin
Martin
7 years ago

@ craigsj – curious have you ridden this bike ? Wondering what it is that makes it one of the poorest peddling f/s out there ?

M.C. Slammer
M.C. Slammer
7 years ago

@ ligero- thanks for your insight. I never thought about the Ti bolts.

Mike Smith
7 years ago

Mike from No. 22 Bicycles here. First off, gorgeous work from Funk. It was great to see this bike and Funk’s others at NAHBS this year.

As for anodizing’s impact on a tube’s strength, there’s a big difference between oxidization caused by welding and the “finish” anodizing done by Funk, No. 22 and a small handful of others. The layer of titanium that is anodized by electricity in finishing does vary in thickness, with different thicknesses causing different colours. These thicknesses, though, are microscopic: generally from 2-3 nanometers (or 0.0002-0.0003mm) deep. I’ve never seen any evidence that this has any measurable impact on any performance characteristic of a titanium tube.

I’d welcome test results showing otherwise, but to make the claim that anodizing weakens a tube is not based on any evidence that I’m aware of. Especially when we’re talking about around one hundredth of one percent of a bike tube’s wall thickness being impacted.

For those wanting to geek out further, here’s a paper that goes into a bit more depth: http://link.springer.com/article/10.1007/s11665-011-9860-0.

craigsj
craigsj
7 years ago

@ Martin – no, I don’t need to. I once owned a Moot YBB which took a similar approach and had similarly poor (in fact, worse) pedaling dynamics.

This design is a simple mono-pivot with a main pivot location immediately behind the bottom bracket. Such designs have grossly inadequate anti-squat characteristics that lead to massive pedal bob. These bikes count on a combination of limited travel to mask the bob and/or large amounts of pedal platform in the shock to hide it. You get poor suspension action or poor pedaling dynamics (or both). It’s unavoidable.

Suspension designs such as these failed in the market over a decade ago and are only carried on by boutique manufacturers that don’t understand suspension kinematics. There’s a simple fix for it but these guys are builders, not engineers and their customers don’t know better. They’re drawn in by the exotic materials and the minimal weight without realizing that a simple change that would affect neither of those things would produce a better riding bike.

James
James
7 years ago

@craigsj – My question is the same as @Martin’s. Have you ever ridden a La Ruta? If you have you could not possibly call it “one of the poorest pedaling FS bikes you’ll find.” My La Ruta is only hindered by one thing. My lacking abilities to explore it’s full potential. It handles better than “ANY” of the four 26’ers I have owned. Power to the ground is instant and spot on even over the rooted and rocky pacific northwest trails I ride. The beauty of the thing is that it made me a better rider than I was. Allowing me to ride for up to 6 hours at a clip, with rest and food stops of course, and not feel like I’m trying to unfold a rusty Buck knife of my body when I get off the rig at the end of the ride.

I guess my question would be,… “If your comments are from a riding experience on a La Ruta that went bad, can you please give more details?”

Ride safe.

feldy
feldy
7 years ago

The thickness of the anodized layer is really, really small. See this chart http://web-o-rama.net/titanium/1anodization.html and note the exponent on the vertical axis. So there’s not much brittle TiO2 on the surface to stop the rest of the tube from flexing. E.g. the chart shows 1000 Angstroms for purple which is 0.1 microns which is 0.0001 mm (1 mm being about the thickness of a Ti tube, maybe a little on the thick side)

I’m not sure the discoloration that happens in the HAZ of a weld is a problem in and of itself or if it’s an indicator of issues within the weld.

Cornelius
Cornelius
7 years ago

Isn’t fatigue failure a problem with Ti? Seems like a very workable design for steel.

andre
andre
7 years ago

M.C. Slammer, does not sustain.

Jason
Jason
7 years ago

@MC Slammer I would be interested to see if Seven Cycles could produce an image of a anodized cracked titanium frame. I have even seen wheels built with anodized ti spokes.

bikeduder
bikeduder
7 years ago

20lb FS Ti bike is amazing. Haters gonna hate! :-/ Sorry its not an enduro bike @craigsj

NotAMachinist
NotAMachinist
7 years ago

@Cornelius
Short answer: Nope

Longer answer: Both steel and Ti have an endurance limit: a stress below which the material will never fatigue and fail. Keep the stress below that point and it won’t develop a fatigue crack. While eventually all metals will fatigue and crack, in practice you will wear out long before a well designed and made steel or titanium frame.

http://en.wikipedia.org/wiki/Fatigue_limit

carbonfodder
carbonfodder
7 years ago

I for one would be willing to ride the living sh!t out of that bike for as long as I could. Purely in the name of science mind you, not because it is one of the nicest looking bikes I may have ever seen. Just sayin’. Willing Science Tester

ascar larkinyar
ascar larkinyar
7 years ago

although a fantastic built and finished bike, the design makes this is a retro build and should be compared to vintage bikes.

the inherit design flaw can be some what tamed through shock over dampening, but to the sacrifice of suspension efficiency and ride quality. shortening the travel(80mm) and tightening the shock response makes it an average soft tail at best.

ecstatically i like non-pivot designs, but not for riding. most 4 link suspensions way out perform this design for climbing(pedal bob) “and” for bump compliance.

as far as comparing ti bolts to ti frames, apples and oranges, the flex parameters are quite different. and fatigue plays a higher role there. no doubt this would be a fun bike to ride, even with the extra long chainstays……

Rico
Rico
7 years ago

I would love to read what the lords of the weld at firefly say about the anodizing. If they haven’t already I bet tyler would test a tube out of curiosity.

Fan Boy
Fan Boy
7 years ago

for those carrying on about the position of the main suspension “pivot” (plate), chuck a Cane Creek INLINE in there and slightly dial up the low speed compression damping a little.

Shock technology can do a lot of things.

Drew Diller
7 years ago

@craigsj – have you ridden a pair of SiCCC rotors yet? What are you basing the poor braking performance on? I have no experience with them. They’re basically a carbon composite where instead of epoxy binding, it’s a ceramic binder.

I wouldn’t go in on the flex plate thing myself, but I 100% disagree that “frame builder” and “suspension designer” are mutually exclusive titles.

Dave D
Dave D
7 years ago

Saying a Moots YBB has poor pedaling dynamics is just…odd. the bike had barely over an inch of travel. I still have a Dekerf softail that has the identical Moots shock (basically just a spring) with ti chainstays mated to a steel frame and seatstays. You could barely even feel the suspension working. It certainly didn’t rob any any power from your pedal stroke.

Dan from Funk
Dan from Funk
7 years ago

Thanks for the feedback on the bike, particularly the positive, but also the negative because it brings up some interesting points.

First off a minor one… the chain stays on the show bike are only 17.35” / 440mm. I’d consider that to be on the shorter end of the scale. Our standard bike has stays that are 0.4” longer; we were able to shorten them on this bike by moving the flex plate to the top of the BB and bending and offsetting the seat tube.

In terms of Seven’s take on anodizing, as Mike said, if they have evidence to back up their claim, I’d love to see it, but as far as I’m aware it’s without real basis. Sure, Ti oxide is detrimental within a weld (inhibits grain formation), but it’s an issue there because the metal is molten and the oxide can migrate around within the HAZ and lead to a weakened structure. But that doesn’t mean it needs to be kept off a frame for the rest of it’s life, nor in fact can it be: the surface of a Ti frame will oxidize on it’s own over time, albeit a thinner and less visible layer than when anodized. That’s why an old brushed Ti frame tends to take on a slightly bronze-ish hue after many years. Last I knew Seven had a lifetime warranty (as do we), so they’re clearly not worried about THAT oxide layer.

In terms of the pedaling efficiency of the La Ruta, online forums have made me well aware that it’s not a design that makes sense to everyone on paper. All I can do is try to encourage people to try riding one before criticizing too harshly. @craigsj, I have owned a YBB myself for many years, and while I love the bike in many ways, I agree that it has a tendency to bob. My La Ruta is a completely different animal though, and frankly I’ve ridden it back to back with a buddy’s Tallboy and I honestly don’t think I am sacrificing anything at all in terms of plushness or efficiency… in fact I think he might be. I’m no doubt biased, but I’m a new addition to Funk having bought a bike from them as a customer a couple years ago; I’ve worked my way in more and more over the past year because it’s a company and a design that I really believe in.

Madm3chanic
7 years ago

i like that the builder is responding here! very refreshing.
i would like to further the comment about the flex-plate location that Craigsj brought up- seeing as this is almost a concentric BB pivot location, the bike must have almost no anti-squat built into its suspension at all. my question is, have air shocks progressed to the point that we can tune to low-speed compression enough to almost negate pedal bob? or are you relying on a lock-out lever or something like that?
in theory i fear i must agree with his statement tho- if you are relying on shock tuning or platforms to prevent pedal bob, you are realistically creating a fairly serious compromise in the performance of the shock.
ps i’m a builder too, i feel the love in the frame- not trollin’ just feeding the conversation 😉

Martin
Martin
7 years ago

@craigsj – that’s what I figured you’d say. It’s kind of pointless to
Debate the bike seeing youve never even thrown a leg over it and are
Still going to compare it to a soft tail. But that aside and speaking about to soft tails what about Castellano ? He’s a MIT engineer I believe are you saying his suspension platform sucks too ? Come on Craig you can do better than those blanket statements.

CLancelot
CLancelot
7 years ago

Gotta say that is the best looking flex plate I’ve ever seen.

Kovas
Kovas
7 years ago

Hey there Bikerumorers… I own a LaRuta. Two of them (one is my wife’s). And yes – we pedal the crap out of them all over CO. Front Range to Fruita. Unlike other soft tails (like Moots YBB), the LaRuta uses a true air shock – of your choice. In my case, a high volume-canned Fox. It took a ride or two to dial in the dampening & rebound, but since then its been set-it and forget-it. Whatever bobbage is there, it’s negated by the shock’s platform setting. Best part: no bearings means no maintenance. Less time in the garage, more time on the trail.

Sure there’s plusher, longer-travel rigs out there. But let’s be honest folks – It’s 80mm of travel (at best). You can’t compare it to a four-bar linkage, DW link or VPP. Apples to pumpkins. As custom soft tails go, it sets the benchmark.

If your definition of enduro riding is 3 hours up for every 1 hour down (you earn your turns baller style), the LaRuta is hard to beat. My 2 cents.

andre
andre
7 years ago

How about comparing this frame with a cannondale scapel 2010-2011 (around that)….also pivotless. Just don’t tell that scalpel was a softtail.

Drew Diller
7 years ago

I also like that the builder is responding, refreshing indeed. And @Kovas, thanks for your candor as well.

If that’s the answer (“yes, modern air shocks and short travel makes up for a convenient but simple suspension design”)… okay. Yeah. I find that acceptable. I mean, I find the travel on a Thudbuster useful for its intended purposes, and it has no damping whatsoever.

Tom
Tom
7 years ago

Wouldn’t moving that flex plate up an inch or two really help out? Isn’t that why the Cannondale Scalpel changed it’s design from pivotless to a pivot 2″ above the BB?

IMO a flex plate built above the BB (2″ or whatever the optimum is) with no other pivots, and Ti would be the ultimate XC FS bike. Almost no maintenance, and about the same pedaling efficiencies as pretty much every single pivot XC race bike out there.

me
me
7 years ago

Dan from Funk, This blue/purple anodizing color is a perfect match with some PROTI Fully Forged Titanium Bolts. Not only the best in the market, but they have a very nice Blue color available. Consider that for your future projects. Congrats on the bike!!! VERY NICE.

Kevin Hodgson
Kevin Hodgson
7 years ago

I’ve ridden SICCC rotors. They’re absolutely awful. Everything works brilliantly, after from them having about half the braking power.

Dan from Funk
Dan from Funk
7 years ago

The Kettle rotors are certain contentious… I had a pair lying around so I thought I’d throw them on for the show since they’re light and look cool. Certainly it’s an easy swap if they aren’t up to par. I was surprised that there were a number of gravel road bikes at the show with Ashima AiNeon rotors which are also crazily light (Moots, Boo among others).

We don’t build the La Ruta claiming it to have the most advanced suspension design. Our claim is merely that it’s the simplest, the most reliable and easiest to maintain, and yet still extremely effective. I think the bike is a soft-tail done right, and it excels on long cross country rides. It’s not built to be an all-mountain or enduro bike. Despite what one might think about the pivot location (this is actually hard to pin down somewhat because the bike doesn’t flex at a single point, or even in as a simple a way as one might think), it is an extremely efficient pedaling bike with the shock set to pro-pedal. Yes, it does get a little more plush if one opens the shock fully, and yes it does become more likely to bob under hard pedaling. But as I alluded to before, with my La Ruta in pro-pedal, it bobs less than my friend’s Tallboy in the same setting, and I think the rear is just as active. If I’m riding the bike on smooth terrain, I forget I’m riding a full suspension bike because it feels almost like a hardtail, and yet when I hit rougher trails and technical sections, the suspension makes itself felt.

To address Craigsj, Tom, and Madm3chanic’s points about the pivot location, and why we don’t try to raise it… this isn’t a new idea, and in theory it’s obviously a good one. The trouble is that doing so becomes quite difficult without greatly complicating the design and fabrication, and in so doing losing a lot of the great things about the existing bike. The flex plate takes a LOT of stress, and the attachment of it’s leading edge to the frame has to be very strong structurally. That’s why we build it with the thickest walled BB shell that Paragon make, and it has a triple-pass weld to make sure it’s as strongly attached as it can be. It’s just not possible to mount the plate to a thin-walled tube like the seattube or the downtube – it would tear the tube within 100m of riding. To raise the plate would require building up a structure to raise it above the BB shell, and that’s going to add a lot of weight, complication, and frankly visual complexity to a design that is at present elegantly simple. The other issue is that plate needs to be close to parallel to the chainline, otherwise the forces from pedaling will over time cause it to buckle. That presents an issue if the plate is raised up above the bb, but then needs to avoid the chain (angle up or down) as it moves to either side of the tire. Basically, the plate can’t do this, the chainstay tubes would have to. But that wouldn’t leave much room at all for the plate, especially since as it gets higher, the tire is further forwards and eating up space. I’m not sure that any of these issues are entirely insurmountable, but in combination I think it isn’t possible to get around them all and preserve the elegance and simplicity to the design that we value so highly. And frankly, given how well the bike rides in it’s current form, I sincerely question whether it needs it.

One more comment on this subject: not sure whether people noticed, but the flex plate in the show bike is mounted onto the top of the BB shell rather than it’s center, which is the way we (and everyone else) normally mounts it. Admittedly it’s only about 0.875″ higher, but this ought to be a somewhat better pivot location, and yet preserves the visual simplicity. At least that was my thinking.

Dan from Funk
Dan from Funk
7 years ago

@me (Andre Szucs?) those Proti bolts are indeed lovely – nicest around, and the blue/purple ano is definitely nice. In the end the main factor was just that I wanted to do all the anodizing on the bike myself, and I had trouble justifying the extra cost for the proti. I went for a mid range blue on all the bolts that matches the color in the center of the fade on the headbadge and the downtube logo.

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