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Dark Owl available for pre-order! Steel is back baby!

troy

Turbo Monkey
Dec 3, 2008
1,026
785
So, as some of You know, I've been building custom bikes for quite some time. Everything started back in 2008 with the rectangular tubed DH01, and has evolved over time.

It was quite long refinement process. Meanwhile two of my riding buds joined the Dark Owl team. We went through many prototypes, but the amount of FEA work and extensive fatigue testing paid of. We make our frames in Poland with USA made, Plymouth Tube Co. - ProMoly 4130 tubing! The only exception is the 3D printed steel head badge, that we are making in Netherlands. All the CNC work, bending, welding is made locally. We do offer custom sizing and sell directly to the customers.

DH02 is the ultimate downhill race frame, designed with roughest and gnarliest tracks in mind. Perfect combination of aggressive geometry, slack angles and outstanding 4-bar, high pivot suspension performance. We do ship globally, so You can place a pre-order at www.dark-owl.com !

* No bottle cages
* Not enduro specific
* No FSR sticker
* No carbon
* No BS
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William42

fork ways
Jul 31, 2007
4,012
771
Can I put a motor on it for climbing and XC rides? Can I drill holes in the tubing for a bottle cage?
 

troy

Turbo Monkey
Dec 3, 2008
1,026
785
27.5"
150mm (5.9") rear travel
23mm (0.92") rearward axle path
65deg HA,
340mm (13.4") bbh,
420mm (16.54") static CS, 430mm (16.93") @ sag,
75.5 deg. effective SA.
shitload of room for big rear tire (possibly up to 29x2.5" if I will decide on removeable/swapable dropouts to lower the bb and make some more tire clearance), now it has 0.8" of space between the 27.5x2.5" tire and the top of swingarm and ~0.5" on each side.
1 bottle cage in the main triangle (hopefully 2)
FUN
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Happymtb.fr

Turbo Monkey
Feb 9, 2016
2,066
1,437
SWE
Nice!
I kind of like big wheels so make 29er possible if possible.
Then metric and non metric shock compatibility would be nice
 

troy

Turbo Monkey
Dec 3, 2008
1,026
785
Nice!
I kind of like big wheels so make 29er possible if possible.
Then metric and non metric shock compatibility would be nice
Punkduro frame will have bolted on/removable lower shock eye mount, just like the dh bike, so it is cheap and easy to "update" if needed.
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iRider

Turbo Monkey
Apr 5, 2008
5,686
3,143
Yup, short link 4-bar. PM180, yes.
Sounds interesting. PM180 not so much. There are folks that might once in a while want to run 160 mm discs. Could you do a solution like on the Last Ice DJ frame? Or better IS?
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,589
2,021
Seattle
PM 180 is great. Stays seem a little on the short side, what's the thinking there?
 

troy

Turbo Monkey
Dec 3, 2008
1,026
785
@iRider , why would You like to run 160mm rotor anywhere except xc and maybe trail bike? I don't want to sound like an ass, but if someone is running 160mm disc at the rear, then maybe 65deg HA bike is not what he should look for. I do not think that IS mount is such a bad idea after all, as it is actually the lightest and most versatile setup imho, although it looks kinda messy.

Short stays are more fun to ride. It is +10mm at sag and +20mm at 1/2 of travel, so it is close or even greater than most of vertical/forward moving axle path bikes that dominate the market. Why should I go with longer stays?
 

iRider

Turbo Monkey
Apr 5, 2008
5,686
3,143
@iRider , why would You like to run 160mm rotor anywhere except xc and maybe trail bike? I don't want to sound like an ass, but if someone is running 160mm disc at the rear, then maybe 65deg HA bike is not what he should look for.
Light rider, strong brakes, not much elevation (heat buildup), surface without much traction. Seriously, if you are living in places with little elevation but still ride for the downhills then you appreciate a good geometry but don't need the raw power and heat shedding capabilities of large rotors. Helps with modulation too.

I do not think that IS mount is such a bad idea after all, as it is actually the lightest and most versatile setup imho, although it looks kinda messy.
Agree on light and versatile. Advantage is also that you don't have threads in the frame that can strip out.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,589
2,021
Seattle
Really I'd love to see someone varying chainstay length with frame size. I get that it's more engineering work and more, different parts to make and distribute, which is why nobody does it, but keeping the ratio of front center to chainstay length fairly consistent across frame sizes makes a lot of sense. That ratio has a lot to do with how the two wheels weight up relative to each other, and how the bike balances.
 

troy

Turbo Monkey
Dec 3, 2008
1,026
785
Light rider, strong brakes, not much elevation (heat buildup), surface without much traction. Seriously, if you are living in places with little elevation but still ride for the downhills then you appreciate a good geometry but don't need the raw power and heat shedding capabilities of large rotors. Helps with modulation too.



Agree on light and versatile. Advantage is also that you don't have threads in the frame that can strip out.
Those are some good points.

I will probably end up integrating those alu dropout inserts into my design anyway:
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
1,213
Light rider, strong brakes, not much elevation (heat buildup), surface without much traction. Seriously, if you are living in places with little elevation but still ride for the downhills then you appreciate a good geometry but don't need the raw power and heat shedding capabilities of large rotors. Helps with modulation too.
Keep in mind while (from memory) you still run/like 26" stuff, many people are on at least 650b these days, and there's a 4% braking force deficit when you do that - so in my experience for most scenarios a 180mm rear rotor is a minimum with today's wheel sizes.

For your application though, there's some seriously light 180mm rotors available and the extra leverage over 160mm means that you could achieve a net result that isn't any heavier than an average 160mm (unless you're already using ridiculously light rotors). Some ~100g options on ebay are reasonably priced and work fine - no worse than a 160 anyway.
 

iRider

Turbo Monkey
Apr 5, 2008
5,686
3,143
Keep in mind while (from memory) you still run/like 26" stuff, many people are on at least 650b these days, and there's a 4% braking force deficit when you do that - so in my experience for most scenarios a 180mm rear rotor is a minimum with today's wheel sizes.

For your application though, there's some seriously light 180mm rotors available and the extra leverage over 160mm means that you could achieve a net result that isn't any heavier than an average 160mm (unless you're already using ridiculously light rotors). Some ~100g options on ebay are reasonably priced and work fine - no worse than a 160 anyway.
Fair point, didn't think of that. And yes, I am still on the tiny wheels. So for now I am good as all these frames have IS.
Not a fan of the crazy light rotors. While they produce enough stopping power they seem to eat you brake pads in no time (Ashima and clones).

Just curious: how did you come up with the 4% deficit? The weight of the system (bike + rider) doesn't change much, so the overall weight that has to be stopped doesn't change. Only thing is that you have more rotating mass further out in 650B/29" wheels, so more kinetic energy?
 

Flo33

Turbo Monkey
Mar 3, 2015
2,135
1,364
Styria
Fair point, didn't think of that. And yes, I am still on the tiny wheels. So for now I am good as all these frames have IS.
Not a fan of the crazy light rotors. While they produce enough stopping power they seem to eat you brake pads in no time (Ashima and clones).

Just curious: how did you come up with the 4% deficit? The weight of the system (bike + rider) doesn't change much, so the overall weight that has to be stopped doesn't change. Only thing is that you have more rotating mass further out in 650B/29" wheels, so more kinetic energy?
The leverage of the bigger wheel the brake has to work against is 4% higher compared to the smaller one.

The ETRTO numbers give you this:
584/559 = 1.044722 ≈ 4%
 
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troy

Turbo Monkey
Dec 3, 2008
1,026
785
Really I'd love to see someone varying chainstay length with frame size. I get that it's more engineering work and more, different parts to make and distribute, which is why nobody does it, but keeping the ratio of front center to chainstay length fairly consistent across frame sizes makes a lot of sense. That ratio has a lot to do with how the two wheels weight up relative to each other, and how the bike balances.
Yeah, it makes sense, but such a move comes with some drawbacks. I've seen Norco and Liteville doing it on some of their bikes. It may sound stupid at first, but giving customers too many options becomes PITA at some point. Sliding dropout inserts, like those I've shown above, are better option imho. +10mm (~0.5")of adjustment and a second slot for 29". Clean & simple.