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Bike Check: Kova Bikes #2 Is A Machined & Bonded High-Pivot Engineering Project

May 8, 2024 at 6:18
by Seb Stott  
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Most students leave university with a piece of paper, a pile of debt and a hangover. But mechanical engineering students from Finland, Jere Laine and Tommi Riite, have something more tangible. Two years ago they decided to combine their passion for mountain biking with their engineering know-how to create a rideable and innovative enduro bike for their thesis project. By the looks of it, this isn't just another homemade bike but something made with impressive craftsmanship and attention to detail.

The foundation of their Kova Bikes Number 2 prototype is a lugged design - something that's becoming more popular, with Atherton, Specialized, and Pivot all using it at the highest level - with CNC-machined aluminum lugs bonded to carbon tubes. This method doesn't require heat treatment during manufacturing, which Jere and Tommi claim results in tighter tolerances compared to some mainstream manufacturers. The lugs are machined out of 7075-T651 aluminum (this is very different from the 3D-printed titanium lugs used by Atherton) and the carbon tubes are sourced from a European manufacturer.

The suspension kinematics are based on the Kavenz VHP (virtual high pivot) platform, subtly modified. The geometry, with a 485mm reach and 640mm stack, is based on bikes the pair have owned and enjoyed. The dropouts and seat stays are modular, enabling customization of chainstay length and rear triangle stiffness. A modular lower shock mount further enhances versatility, accommodating rear travel figures from 120mm to 180mm. The bike shown here is running 162mm of travel and a 425 mm chainstay length (438 mm at sag).

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A BB/downtube/seat-tube lug taking shape on the CNC machine.
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The improvised glueing jig on a welding table.

The engineers used Fusion 360 and Siemens NX software for the computer-aided manufacturing process. The bonding jig, for accurately glueing the carbon tubes into the machined lugs, was made by simply modifying a welding table with parts they custom machined to hold the lugs in place. This worked well enough for the run of four frames they made but would need to be improved for bigger batches.

To complement the frame, a full set of silver Hope components and a Fraezen cockpit were chosen, along with EXT suspension. The bike as shown sneaks under 17 kg (37.5 lb).

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Lugs and machined parts for four frames.

The pair are grateful to have benefitted from unlimited access to machine time and almost unlimited amounts of aluminum. Even so, these four frames represent around 2,000 hours of work. They don't recommend their approach to first-time frame builders.

Kova Bikes doesn't have any commercial plans. "We just love it as a hobby and are looking forward to a full summer of field testing with the prototypes," says Jere Laine. "Maybe after summer, we will find ourselves back at the drawing board again. However, we both graduated as mechanical engineers in January and we hope that this project will be helpful in getting to work in the bike industry or something related to machining."

You can follow the project on Instagram.

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Buid Details
• Frame: CNC machined 7075-T651 aluminum lugs bonded to custom made carbon tubing from Europe
• Fork: EXT Era V2.1
• Shock: EXT Aria
• Wheels: DT Swiss FR541 with Hope Pro 5 Hubs, Mullet
• Tires: Continetal Kryptotal with Pepis R-Evolution
• Drivetrain: Hope Evo cranks with 32T Hope chainring. Sram GX AXS derailleur
• Brakes: Hope Tech 4 V4 with 200mm floating rotors
• Cockpit: Fraezen stem with Title AH1 Handlebar
• Pedals: Crankbrothers Mallet E Silver
• Headset: Enduro Bearings Maxhit ZS44/ZS56
• Bottom Bracket: Enduro Bearings Maxhit BSA30



Photos: Jere Laine / Kova Bikes

Author Info:
seb-stott avatar

Member since Dec 29, 2014
321 articles

58 Comments
  • 120 0
 Considering its a prototype the level of Finnish is very impressive
  • 115 1
 Do you know why the Finnish navy has bar codes on their ships?
Its so they can Scan-da-navy-in.
  • 5 0
 They will definitely be worth a lookova once released
  • 21 10
 @ratedgg13: Finland is part of Scandinavia the same way that Canada is a state in the US.
  • 49 2
 @Nygaard: I'm sorry my stupid joke wasn't geographically accurate. I will note that all further jokes must be 100% accurate.
  • 24 2
 @Nygaard: also they don't have barcodes on their ships.
  • 5 0
 @RonSauce: Yes they do, it's how they open the door to get into the bar!
  • 6 0
 It was a bit dull of a joke, you should polish a bit more next time.
  • 5 7
 @ratedgg13: except Finland isn’t part of Scandinavia….
  • 7 2
 @Nygaard: To be fair, Wikipedia does list Finland as "sometimes" being included as part of the Scandinavian Peninsula.
  • 3 1
 @Bollox64: American humor doesn't always translate well. Sometimes we think it's funny just to be stupid.
  • 1 0
 @Nygaard: message retracted.
  • 3 0
 @Nygaard: we are, just not treated as well as say, Puerto Rico
  • 1 0
 They use QR codes these days, duh.
  • 40 1
 When cove and kona are already taken...
  • 8 0
 Kona, not so much...
  • 11 1
 “Kova” means “hard” and “tough” in Finnish. Also it can be used to mean “cool” or “rad” or along those lines anyway. Not that anyone wanted to know this. But the bike is super nice, and the guys have done an amazing job down to every detail. Discussed the gluing process a bit with one of them, and they know what they’re doing. Pivot should hire them.
  • 2 0
 @FIN599: the Kova name is already taken by a custom Goalie accessory and equipment maker... they make incredible neckguards and a few other things.
  • 7 1
 What’s next? Trev? Specialived? Cannondave?
  • 19 0
 EXT on a student budget. Hella jelly.
  • 6 0
 its not the us so they can probably get most of the cost of all parts and materials covered by their schools engineering program.
  • 15 0
 Seriously impressive work for two students, well done!
  • 11 1
 Hey PinkBike we get a lot of these stories about home spun proto bikes (which is awesome) but it’d be rad to see what’s required from a testing standpoint before a frame can go to market. Also, how much modification can happen after that testing is complete without triggering a do-over? And do they test all sizes? Please and thank you.
  • 8 1
 At least for small builders, there are no testing requirements. There are various testing standards out there that would be smart to meet, and no guarantee that someone won't try to sue you if the bike you built them breaks, but custom frames would be prohibitively expensive if they had to test every design before selling.
  • 1 3
 @MTBLegend92: wow that’s scary AF. Might explain why I keep breaking frames
  • 2 1
 @Blownoutrides: Plenty of frames from big brands fail too, great example is the Commencal Headtube fiasco from a few years back
  • 5 0
 Kavenz has some nice videos showing the testing process, here's one:

youtu.be/oHqJA_HrzYs?si=zepQxXfop0YlQHJj
  • 1 0
 @KolaPanda: Don't forget the Supreme DH v4.3 to v4.5 cracking near the BB
  • 4 0
 ISO 4210 and ASTM F2043 describe a lot of the testing requirements that frames and forks should meet as a minimum standard. Having frames tested to meet or exceed those benchmarks isn't actually all that expensive, but is a level of cost and effort that almost nobody except major brands goes to. I can think of a single-digit number of custom frame builders who test their frames at all, let alone to those standards.

That being said, the world of actual brands and manufacturers is vastly different, and testing in that world (even for small brands) is rigorous and intensive. Passing testing is no guarantee that something won't break, but is a good check that real engineering has happened with an eye toward performance and safety.
  • 6 0
 Go follow Ministry Cycles on IG. He's been posting for a year or two daily about what it takes to get a bike from testing to the market, including footage of it getting tested and pictures of the failure points and the steps it takes to address the stress areas.
  • 2 0
 @miniondhr: ISO standards aren’t law, and thus not mandatory.
  • 1 0
 @MTBLegend92: won't try to sue you if the bike you built them breaks

It's Europe so maybe they're not as dead-ass broke as a student here, but maybe get their used futon or a MC Escher poster in the settlement?
  • 12 1
 Wow 5 axis and a pro welding table? With a prototype batch of 4? This was a cakewalk for them, definitely pros at work. Far cry from the typical “shed” prototypes haha
  • 11 0
 Looks like the love child of a Kavenz VHP 16 v6, and the Pivot lugged carbon prototype DH bike.
  • 10 0
 Definitely not a lugged Kavenz
  • 3 0
 Pretty badass bike to base their design on.
  • 8 0
 Kona is back!!!! Oh….
  • 7 1
 I thought it read KONA. Ha! Should have known better. KONA hasn't been that creative/innovative in a decade
  • 1 0
 I read the same at first
  • 3 0
 "The bike shown here is running 162mm of travel and a 425 mm chainstay length (438 mm at sag)"
This "438 mm at sag"!
Big brands (every brand) you can all add this real world useful piece of information to your geo diagrams henceforth please so I can actually compare an apple to an apple rather than an apple to a cumquat.
And you could start using averaged effective reach, also at recommended sag, (centre of seat post/ saddle to centre of bar; with saddle at averaged saddle height for the inseam of the size of rider that the frame size is aimed at) to help the consumer too whilst you are at it.
  • 6 0
 Bondage is so hot right now
  • 2 0
 Yeah,lots of us would like to spank the rear on this one
  • 6 0
 Nice Thesis project.
  • 4 2
 "(this is very different from the 3D-printed titanium lugs used by Atherton)"

And is very much the same as the machined lugs used by Atherton on the A-series.
  • 4 0
 Kova Stinky Dee-Lux
  • 5 0
 Kova Stinky Dee-Lugs
  • 3 0
 Kova Sticky Dee-Lugs
  • 3 0
 Wow. Awesome so far. Great work!
  • 3 0
 You're all wrong. It looks like a Giant NRS
  • 2 1
 Pretty rad. In 20 years we'll all be able to design and build our own bikes like this.
  • 1 0
 A full 3d-printed metal main triangle with internal isogrid would be fun to make, assuming good material properties and decent cost at some point, someday.
Design and send to a 3d print / proto shop, then final assembly at home using catalog hardware.
Will be a great way to get custom geo exactly the way you want it.
(and then realize "oops I should have made the chainstay longer by 3mm" lol)
  • 2 0
 Is this not proof that we already design and build our own bikes?
  • 1 0
 Looks like the new trek slash
  • 1 0
 That bike looks very much like the Rocky Mountain ETSX!
  • 1 0
 Wow! Impressive Good luck guys!
  • 2 0
 Grade A work.
  • 2 1
 Huck to flat!
  • 1 0
 Love the Buid details!







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