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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

troy

Turbo Monkey
Dec 3, 2008
1,026
785
So yeah... my 3-roller bender destroyed the tubing. Had to use too much pressure to achieve desired bending radius... I've made some custom tooling for the CNC mandrel bender. Here is a pic of it, making some downtubes for the DH02 frames :)
gięcie 2.jpg
 
troy

troy

Turbo Monkey
Dec 3, 2008
1,026
785
laggard said:
have you tried using Cerrobend?
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We have tried packing the tubes with a very fine sand and welding the tube ends. It helped a little bit, but it was still looking quite terrible. This Cerrobend sounds good for a 1 time job, I cannot imagine using it for bending like 100 of tubes tho. I'm not the biggest fan of beeing anywhere near cadmium, bismuth and lead either... :twitch:
 
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troy

troy

Turbo Monkey
Dec 3, 2008
1,026
785
TrumbullHucker said:


clean as fuk, mate!!

what are you using for clamping? as you know, death to weld distortion!!
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Thanks man. 1st frame will be clamped to a standard duty welding table. 1st/next batch of frames (for sale) will be made in a special jig/tool :)

rpet said:
Why the bendy down tube?
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For much stiffer headtube and shock resi clearance ;) *





*and for the lookzz ofc
 
Westy

Westy

the teste
Nov 22, 2002
56,237
22,267
Sleazattle
tacubaya said:
I demand leverage ratio graphs drawn with a crayon and an explanation of why the linkage would've been chosen by Jezuz.
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Quoted for truthiness. Not necessarily in regards to this thread. This thread is awesome.
 
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troy

troy

Turbo Monkey
Dec 3, 2008
1,026
785
@Kevin, You have mistaken me for a guy from Tantrum Cycles :D Even tho my company is not building gazillion frames in taiwanese factories I have hired proffesional graphic designers to make my website, frame painting and whole branding stuff (unlike mentioned fella). Website should be up in a couple of days.

Everything is painted on the frame, no decals. Sorry bro ;)
 
Udi

Udi

RM Chief Ornithologist
Mar 14, 2005
4,918
1,213
Hey @troy I just noticed the frame weight is 8.6lbs without shock, is that still correct? That's quite impressive for a steel frame and competitive with a modern alloy frame. Did you end up going 650b or staying with 26"?

Do you think it will get even lighter in the future or is it likely near the limit of optimisation?
Any concern for denting of tubes in crashes or do you think it'll be pretty good?

I'd love to have a ride one day, I feel this fits within pretty much all my ideal values for kinematics and geo. I'll take a 650b version with 48.5" WB / 13.8" BB / 63* HA. :D
 
norbar

norbar

KESSLER PROBLEM. Just cause
Jun 7, 2007
11,506
1,722
Warsaw :/
Udi said:
Hey @troy I just noticed the frame weight is 8.6lbs without shock, is that still correct? That's quite impressive for a steel frame and competitive with a modern alloy frame. Did you end up going 650b or staying with 26"?

Do you think it will get even lighter in the future or is it likely near the limit of optimisation?
Any concern for denting of tubes in crashes or do you think it'll be pretty good?

I'd love to have a ride one day, I feel this fits within pretty much all my ideal values for kinematics and geo. I'll take a 650b version with 48.5" WB / 13.8" BB / 63* HA. :D
Click to expand...
Wasn't that the problem with the superCo?
 
troy

troy

Turbo Monkey
Dec 3, 2008
1,026
785
Udi said:
Hey @troy I just noticed the frame weight is 8.6lbs without shock, is that still correct? That's quite impressive for a steel frame and competitive with a modern alloy frame. Did you end up going 650b or staying with 26"?

Do you think it will get even lighter in the future or is it likely near the limit of optimisation?
Any concern for denting of tubes in crashes or do you think it'll be pretty good?

I'd love to have a ride one day, I feel this fits within pretty much all my ideal values for kinematics and geo. I'll take a 650b version with 48.5" WB / 13.8" BB / 63* HA. :D
Click to expand...
Had to beef it up a little for EFBE DH specific testing (MUCH higher loads than EN testing), it should weight ~ 9.4lb w/o shock (w8ing for it to be painted). There is a room to shave it down to sub 9lb for sure, but we want to keep the price ~2000 USD with DVO Jade shock, so even more CNC work is not an option right now (when we will scale up our buisnes, and buy some machines, we will make it lighter for sure).

Frame will be 650b and 26" compatible (2nd shock eye). The geometry stays roughly the same, with 650b CS goes from 16.34" to 16.57" (1"/0.8" of rearward travel).

We are using straight gauge tubing only, so dents shouldn't be an issue. Silencer was built on True Temper double or tripple butted tubing - those tubes help to shave some weight but have REALY thin walls at the same time.

CS is 16.57" WB is 48.1", 13.5 BB and ~62.5HA (depending on the headset for 650b setting with 0.4" tire clearance from each side (with a 2.5x650b tire - 28.15" dia., 2.6" wide). You can use 26" setting to get it a little bit higher & steeper but there will be slightly less space between the CS bridge and the tire.
 
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troy

troy

Turbo Monkey
Dec 3, 2008
1,026
785
sikocycles said:
Since 29 is cool again will the be a 29" model?
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HOO knows?

I have ridden couple of 29"ers this year and I kinda liked it. Kinda is the key word here, because suspension on those bikes sucked and geometry was not so great either (for DH use ofc). But the rollover abilities were there and I can see some potential. The problem is with the availability of proper DH tires and rims. Correct me if I'm wrong.
 
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