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Dark Owl DXX (Fatigue testing vid page 6)

How long chainstay should be at SAG point?


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troy

Turbo Monkey
Dec 3, 2008
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Hawt.

Any idea when they'll be available?
We will probably do some kickstarter thing soon with the downhill frames so we will have some funds for new projects. We would like to make punkduro frames available before the next season for sure.
 

Muddy

ancient crusty bog dude
Jul 7, 2013
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We will probably do some kickstarter thing soon with the downhill frames so we will have some funds for new projects. We would like to make punkduro frames available before the next season for sure.
You've some solid interest brother! The IH 6POINT being the only frame(s) since 2009 has found and has reached it's limits. While it fits me well, the frames geo really needs more concentrated front-center while retaining it's back-half stuffs.

This fact you're choosing steel is a wad of cred' toward your company image; am wanting more specs once they're made ready for a 6- 7" travel bike / frame. I really like the 12x150mm rear-axle and the wide BB shell the Iron Horse train kept a' rollin' - but I know they're against other things to be considered ordinary and stable now.

Headtube badges for one.

Whatev's - you have an interesting, attractive offer on the upstart. Some Maple Syrup for your Bourbon, Dark Owl. :pilot:
 

4130biker

PM me about Tantrum Cycles!
May 24, 2007
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Is it possible to do 73 BB and 157 rear so there is better crank selection?
Maybe this is close to "super boost" (157 based) thing that pivot did?
The bikes are looking killer, by the way!
 

troy

Turbo Monkey
Dec 3, 2008
1,006
739
Is it possible to do 73 BB and 157 rear so there is better crank selection?
Maybe this is close to "super boost" (157 based) thing that pivot did?
The bikes are looking killer, by the way!
Sure, everything is possible. Summum had 73/150mm combo, but the chainline sucked iirc. Maybe with an asymetric rear end or dished bb shell? Anyway, why 150mm rear end when You can achieve the same with 73bb - 142x12 setup? Dh - enduro bike parts interchangeability?
 

troy

Turbo Monkey
Dec 3, 2008
1,006
739
7" frame, 12x150mm rear, 83mm BB. These are a few of my favorite-things...
Not sure about that 7" of travel. Punkduro frame has 6" with 3/4" of rearward travel. That missing 1" shouldn't be a problem IMHO :)

PS sorry for 2 posts.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
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Seattle
Yeah, don't make it 150mm rear. You're already going to be a small volume, niche brand, at least at first. Completely bucking convention on that kind of stuff is just going to limit your appeal. You can get away with goofy shit when you're Trek and can just shove it down people's throats, but as the little guy, make things easier on yourself.

Like you said, unless you either use am 83mm BB or offset everything and redish the wheel, the chainline will suck. If you use an 83mm BB, you severely limit crank options, particularly for ones that aren't boat anchors. If you redish the wheel, then you've lost your DH bike swappability, which is the only even vaguely reasonable argument I can think of for going 150mm rear. And I don't want to run the same wheels on my Endurbro and DH bikes anyway. DH wheels are heavy. I think most people would agree.
 

Muddy

ancient crusty bog dude
Jul 7, 2013
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Not sure about that 7" of travel. Punkduro frame has 6" with 3/4" of rearward travel. That missing 1" shouldn't be a problem IMHO :)

PS sorry for 2 posts.
The 7" travel figure would continue use of 26" wheelsets. Just something which has been getting it done for a good stretch.

Yeah, don't make it 150mm rear. You're already going to be a small volume, niche brand, at least at first. Completely bucking convention on that kind of stuff is just going to limit your appeal. You can get away with goofy shit when you're Trek and can just shove it down people's throats, but as the little guy, make things easier on yourself.

Like you said, unless you either use am 83mm BB or offset everything and redish the wheel, the chainline will suck. If you use an 83mm BB, you severely limit crank options, particularly for ones that aren't boat anchors. If you redish the wheel, then you've lost your DH bike swappability, which is the only even vaguely reasonable argument I can think of for going 150mm rear. And I don't want to run the same wheels on my Endurbro and DH bikes anyway. DH wheels are heavy. I think most people would agree.
12x142mm never displayed any true benefit at first, it may have been along time ago - but it happened.

Why so many cranksets? All that'd be needed is one set... :homer:
 
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HAB

Chelsea from Seattle
Apr 28, 2007
11,580
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Seattle
The 7" travel figure would continue use of 26" wheelsets. Just something which has been getting it done for a good stretch.



12x142mm never displayed any true benefit at first, it may have been along time ago - but it happened.

Why so many cranksets? All that'd be needed is one set... :homer:
Yeah, I agree that 142 isn't much better technically than the 135x12 that it replaced, but using common parts still has value.

And with the cranks, again, options are good.
 

troy

Turbo Monkey
Dec 3, 2008
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12x142mm never displayed any true benefit at first, it may have been along time ago - but it happened.
What is the benefit of using 150/157mm hub? Hope Pro hubs (I think they are quite common along enduro and dh bikes) have exactly the same flange spacing (150/157 is symmetrical, 135/142 version is 5mm (0.2") off center). I guess it is not that much different with other manufacturers.
 

iRider

Turbo Monkey
Apr 5, 2008
5,648
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150/157 is symmetrical
And that is what makes the wheel much stiffer. There are two theories amongst hub manufacturers to use the extra width of a 150 mm hub. The one from Hope and others is to build a symmetrical wheel to keep spoke tension even between L+R. Other manufactures use the width for a wider triangulation of the spokes but continue to accept uneven spoke tension between L+R. Both can work if executed correct. Personally I prefer the symmetrical setup because it seems that the wheel stays true for longer that way (at least for me).
 

Muddy

ancient crusty bog dude
Jul 7, 2013
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What is the benefit of using 150/157mm hub? Hope Pro hubs (I think they are quite common along enduro and dh bikes) have exactly the same flange spacing (150/157 is symmetrical, 135/142 version is 5mm (0.2") off center). I guess it is not that much different with other manufacturers.
The 150mm axle I've found to offer a more-damped experience. This, and having a wider frame at the mounting point - to me - tract better than the other options.

157mm is only the other-option to be had with 150mm. The first consideration is to me the balance of the frame. Hub Flanges are the benefit which follows. Symmetrical design as something to be touted would have to have equal length spokes for it to be implemented as a true improvement. Unsure if this is a part of any wheelset, but is far from rear axle choices as a supporting structure.
 

Mo(n)arch

Turbo Monkey
Dec 27, 2010
4,441
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Yeah, actually a new hub width that makes actually sense.

In what sizes will the DH-frame come? Do you have a geo sheet somewhere?
 
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4130biker

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May 24, 2007
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Yeah, actually a new hub width that makes actually sense.
Or, even a stock 157 hub without revised flange spacing appears to offer similar flange width to 148. Wider flange spacing was supposedly the driver for the boost BS. I can't remember Treks excuse for not using 157 spacing, not that it matters...

Unfortunately, a lot of us buy complete bikes (and wheels for that matter) and are kind of along for the ride when it comes to this stuff.
I agree with Hab that something as main stream as possible is probably the smart choice for a small company like this.
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
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Seattle
The 150mm axle I've found to offer a more-damped experience. This, and having a wider frame at the mounting point - to me - tract better than the other options.
I don't believe for second that you could tell a difference on otherwise identical frames.
 

dump

Turbo Monkey
Oct 12, 2001
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I don't believe for second that you could tell a difference on otherwise identical frames.
Oh come on... mtbing today has become a sport of .0005% optimization – gloriously wasting time, money and resources. Look at us here discussing it!

But I'm with you – you'd more likely feel the difference of 0.25psi in your tire.
 

iRider

Turbo Monkey
Apr 5, 2008
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I don't believe for second that you could tell a difference on otherwise identical frames.
Been there, done that. Intense Uzzi VPX and Socom have replaceable dropouts 135/150. The only increase in stiffness came from the evenly tensioned symmetric wheel.

Disclaimer: I know, bad example, because VPP and unridabru. ;)
 

troy

Turbo Monkey
Dec 3, 2008
1,006
739
But the Super boost 157 is not symmetrical, so how can it be stiffer? #trollface

Correct me if I'm wrong, but the 135/142 hub can be tensioned evenly too, by using different length spokes on each side? Difference between the Hope 150 and 135 is roughly 1.4 deg in spoke angle so come on...

The only frame You can actually compare it, is a Demo or an Intense. IIRC there were 2 versions back in the days. One with 150 mm rear end, and some premium, Sam Hill edition with 135 mm hub. Comparing 2 different bikes or even 2 different components wheels is not very accurate.

@iRider were those wheels identical? Like same spokes and rims, laced by the same person etc.?
 

HAB

Chelsea from Seattle
Apr 28, 2007
11,580
2,005
Seattle
Correct me if I'm wrong, but the 135/142 hub can be tensioned evenly too, by using different length spokes on each side? Difference between the Hope 150 and 135 is roughly 1.4 deg in spoke angle so come on...
You're wrong :D

I'll go into more detail later when I'm not at work.
 

iRider

Turbo Monkey
Apr 5, 2008
5,648
3,089
Correct me if I'm wrong, but the 135/142 hub can be tensioned evenly too, by using different length spokes on each side? Difference between the Hope 150 and 135 is roughly 1.4 deg in spoke angle so come on...
You have to use different spoke lengths anyway. But the spokes on the drive side have a steeper angle, so they need a higher tension to keep the rim in position. Similar to you lifting a weight: not much force needed when it is close to your hip, but if your raise your streched-out arm to a horizontal position it is way harder to keep the weight in place.

@iRider were those wheels identical? Like same spokes and rims, laced by the same person etc.?
Deemax Ultimates, so yes. Spoke tension on the disc side of both wheels was similar as verified by a spoke tensiometer.

BTW: Demo is a bad example as it had an off center swingarm to keep the spoke tension even on a 135 mm hub.
 

slimshady

¡Mira, una ardilla!
Demo is a bad example as it had an off center swingarm to keep the spoke tension even on a 135 mm hub.
Si how comes this solution is not moar spread across the industry? Cannondale did it in their FSI XC bike, and back in the day Iron Horse applied It too. I owned a couple of asymetrical frames and I didn't get any odd feelings from them.

I liked the DMR Revolver and SRAM hubs too because they had asymmetrical flanges which helped to mitigate the uneven spoke tension issue.
 
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HAB

Chelsea from Seattle
Apr 28, 2007
11,580
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Seattle
So, like iRider said, when you lace a wheel, the rim is going to end up moving laterally until the lateral components of the spoke tensions balance. Tweaking the spoke tension on one side is how you dish a wheel. In practice, on a typical rear wheel with asymmetric spoke angles, that means that you have higher spoke tension in the drive side spokes.

Increasing this lateral component of the force applied to the rim from the spokes will make a stiffer wheel. You can do this one of three ways:
  1. More spokes
  2. More spoke tension
  3. Wider flange spacing, and therefore a shallower spoke angle
This obviously doesn't mean that more spoke tension is always better though. Tension is limited by what the rim and spokes/nipples can reasonably hold up to (and will increase/decrease around the wheel as you load the wheel and things flex). An asymmetric wheel isn't inherently weak exactly, but it does mean that the side of the wheel with steeper flanges is the limiting factor in how much tension you can put in the spokes. If there's a big difference between spoke angle left to right, you'll need to run substantially less tension in the side with a shallower spoke angle to get the dish right. This means that the component of the spoke tension forces that's in plane with the wheel is lower, because you've got lower tension in that half of the spokes.
 

troy

Turbo Monkey
Dec 3, 2008
1,006
739
And what if I told You that IN REAL LIFE neither spoke tension or wheel dish doesn't really matter in terms of wheel stiffness?

 
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StiHacka

Compensating for something
Jan 4, 2013
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In hell. Welcome!
And what if I told You that IN REAL LIFE neither spoke tension or wheel dish doesn't really matter in terms of wheel stiffness?

It does matter as you can never get the non-drive-side spokes tension anywhere near the rim limit, and the moar tensioned a wheel is the moar stiff, plus the moar robust and less prone to going out of true.

I've just built a 142x wheel with asym rim, and while the tension is not 100% even, it feels like a massive improvement over standard rims. I am quite confident this wheel will significantly outlast my other (otherwise similar) wheels.
 

squiby

Chimp
Jul 26, 2010
91
13
I dunno about stiff lasting longer... seems if I lace carbon rims too stiff they bust the edge a lot easier. That's on regular 147 hubs.
 

mtg

Green with Envy
Sep 21, 2009
1,862
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Denver, CO
And what if I told You that IN REAL LIFE neither spoke tension or wheel dish doesn't really matter in terms of wheel stiffness?

Spoke tension, as you say, does not matter for lateral wheel stiffness, as long as the spokes are tensioned. That's because (as you know), E is E, and does not change with tension. For non-engineers: E is the Modulus of Elasticity, a nerdy name for the material property that is stiffness. Think of it as the spring rate of a block of material.

However, on dishing, the data from Sheldon Brown didn't test different rim dishing to measure differences in spoke angle. It tested loading the same wheel from both sides and noting on differences in stiffness in left turns vs right turns.
I haven't seen any data on measuring wheel stiffness vs spoke bracing angle, but would expect it to be quite influential. The spoke stiffness in tension is fixed at E, and the closer to horizontal it gets, the larger component of E is being used to resist lateral deflection. A caveat could be that bending stiffness could matter, as spokes don't have ball joints on both ends; those connections have some bending stiffness, especially in designs like I9 system wheels.
 

StiHacka

Compensating for something
Jan 4, 2013
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In hell. Welcome!


I admit I mistakenly used stiffness and strength interchangeably. However, all those tests in the article were fairly static. How about effects of tire pressure and dynamic loading of the wheel during big hits etc, can't that get the spokes past the threshold when they are not properly tensioned any more? (even if for very brief periods of time)
 

Muddy

ancient crusty bog dude
Jul 7, 2013
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And what if I told You that IN REAL LIFE neither spoke tension or wheel dish doesn't really matter in terms of wheel stiffness?

Spoked wheels are hardly contained explosions in barely reusable containers.

If all spokes were equal length, there'd be a quantifiable factor to meet and / or exceed in regard to a stiff wheel and it being repeatable in production.

A wheel which has physically exploded like dynamite would be - besides difficult to identify - it'd also be loud. If the wheel blew up from the exact bullseye center of the Hub, the sound oscillations would extend to the Spokes and then to the Rim. The longer the spoke, the more time whatever resonance causing sound vibration needs to make the full exploding wheel sound.

The Moto Mag, Skyway Tuff Wheel 20- & 24" from BMX racing retained the wheel upon mag spokes. Deflection and transfer of torque were of equal vector point-of-origin. Skyway's being the 2nd-iteration of Mag Wheels only found larger-use within Freestyle - too stiff for racing.

I'd built Syntace W35 rims with a heavy drive, light(er) brake and then even lighter non-brake and the same spoke gauge on the front's brake-side. Very compliant wheelset with Hope Pro2 EVO hubs (26") only when including the soft-nature of the Rim. This was pre-ProCore and a time when I was destroying rims often. Ride quality was... something awesome.

Likely an overall inception of symmetry should be found and had with equal length spokes locating hubs square to the rim. There'd also be potentially more structure-failures (drop outs, stays, etc.) and / or overall wear of fasteners and pivots.

The 'dish' of a rear wheel invites slight rear-steer moments which benefit when cornering properly; outside crank arm down with the top side ready to pedal out the corner. Yes Claudio - we're sorry for doing this as no one who exits a corner while racing is cornering the right way, it is how to accelerate a bicycle however. Sorry. Having those moments of compliance to enable traction make traction.

As I rebuild 26" e.thirteen LG1 wheels this winter using staggered spoke gauges I will not be concerned with wheel dish or where my hub flanges are not. How the wheels track and how they respond under load is all that matters and, is able to be dialed in on any bike.

...which is why the 12x150mm rear wheel wins the race. :D