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New odyssey stampy video

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G:

--- Quote from: erenes on January 07, 2015, 08:12:59 PM ---The standard "industry" test setup for forks is: +-650N, with force set perpendicular to the fork, <25HZ, 100.000 cycles. Immagine attaching the front wheel to the wall, then pressing and pulling (only with 65kgs), few times a second, 100K cycles. Any entry level mtb 5us$ fork made of cheap steel should pass this test. Make no sense to test bmx forks this way.

Odsy setup looks good. Stampy jig with build resonable headagle, and force direction like real landings. Resonable 500-600kgs force. Love it.

G, it still weird to see so many competition forks snapped clean at the steertube. In real life I see them cracked mostly at the welds e.g. blades/steertube junction or sometimes dropouts. Not too many snapped steertubes around for the last few years. I hope the new forks are not too light/too thin in this critical point.

One more... G, I think I see different frequencies used [0:50-1:10]. I dont think the video is speed up... I'm guessing only. ?

--- End quote ---

The industry standard tests biggest problem is that they dont mount the fork in a headset, they clamp the steerer directly. This is absolutely ridiculous and makes the test almost completely worthless. Since we started testing this way several MTB companies have followed suit and now test using a proper headset mounting.

Dropout weld cracks are mostly due to peg use and landings off straight, although this may be a fairly common mode of failure it shouldn't be. We very rarely get forks back on warranty with this issue unless there is obvious evidence of peg use with a crappy hub axle (ie. heavy indenting and deformation of the inside of the dropout) the refinements to the 41 thermal process welding and the greater use of big female axles have fixed this for us.

The base of the steerer is where I always expected to see failure. This is where there is maximum bending moment and the unavoidable stress concentration of the headset seat, but different loading regimes will always have the potential to change the mode of failure. If a fork "sees" more side and torsional loads then weld failure is possibly more likely.

Yes in an ideal world we would test multiple scenarios, but we have to deal with the realities of the cost of testing.

:)
G.

dude...:
theres a few people around here still running 14mm front wheels, but the supply of 14mm dirt forks to go with are drying up as they all end up cracking above the dropout on the regular peg side.
not to say this is a fault of the forks, cos everyone still running 14mm forks is doing so because theyre pretty harsh on them. noone bothers warrentying them because most of the time theyre 3-4th hand anyway and thus the warrenty is void, plus theyre not gonna get a replacement set of 14mm forks even if they were able to warrenty them anyway.

ive personally cracked some dirts like that, i think the 06 versions, while using a 14mm odyssey hazard hub

but yeah safety wise its probably better to make sure they dont just snap off clean at the steerer suddenly, if the dropout snaps at least the whole front end isnt necessarily gonna fail and put you on your face. and yeah i can understand its already expensive doing the stampy as is without doing additional testing

JFax:
Is there any difference in strength between fork dropouts made for 3/8īs and those made for 14 mm? or is the difference neglectable?

dude...:
dirt forks had slightly thicker dropouts than the race forks. wasnt really about the fact that they were 14mm, only that people were cracking them then struggling to find replacements. everytime dirt forks come up secondhand they get snapped up really quickly

erenes:

--- Quote from: G on January 08, 2015, 04:55:05 PM ---(...)
The industry standard tests biggest problem is that they dont mount the fork in a headset, they clamp the steerer directly. This is absolutely ridiculous and makes the test almost completely worthless. Since we started testing this way several MTB companies have followed suit and now test using a proper headset mounting.
(...)

--- End quote ---

I would say there is one factor that is about 100x times more ridiculous than 'unreal industry standards'

It is.... to allow outsourcing R&D guys, engineers, agents, official EN testing center engineers - seting up your babies, your products, allowing them to install products into jigs before starting the test. Most of them never rode a bike. If they rode a bike, they never jumped. If they jumped, than maybe the curb, they never rode real BMX.

Of course you can prepare detailed guides about setting up position, angle, tightening torque for your tested products, sketches, drawings, video-guides, anything you want. But there are 10x more setups and cases possible with testing machine elements / jigs than with your products itself. Comparing bars of different width would you setup up them with same width or same distance from the bar ends? Both could be ok depends what you plan to compare/test.

Then easier one, but not always - setting up the machine program itself. I saw so many screw-ups.

I saw so many RIDICULOUS testing done. E.g. comparison fatigue test of saddle+seatpost set of two brands. But the setup, jigs used, and especially the way they bolted saddle + post togeother was so ridiculous, screwed up, upside down. You could immediatelly notice that certified testing center personal never rode ANY bike. They were under influence of HEAVY DRUGS, Im sure.

I think that if you are not there (in Taiwan or somewhere) playing with your babies and competiton products - the test does not count! Only testing done 'inhouse' make sens in long-term.

G: any comments on the different frequence ;) ?

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