Thursday, October 30, 2008

Pinder v Fox

Russ Pinder's case against Fox Racing Shox (MTB fork manufacturer) is finally underway in the High Court. There are two brief articles about it here and here, and lots of ill-informed argumentation on the STW forum as usual, despite the best attempts of the proprietors to shut down any discussion (see 1, 2, 3, 4, 5). It is interesting to see that 5 years after I worked out what was going on and wrote it all down in simple terms, people still seem to feel the need to make up uninformed nonsense (although I'm sure all climate scientists will be familiar with such behaviour). As I mentioned recently, this stuff is not rocket science, it is just the way that bolted joints work (or rather, how they fail if over-stressed) and has been basic engineering knowledge for decades.

I don't know the details of their case, but for the background to the incident that underlies it you can look here and here. It seems like there should be a verdict early next week. I hope they have done their homework and wish them all the best.

14 comments:

Mark said...

James - Ive been following the case in court. Find my update from Friday's interesting session here: http://spoomplim.blogspot.com/

James Annan said...

Mark,

Thanks for posting about it. It's shocking that Fox say they only started thinking about the ejection forces in 2005 - that would seem to be prima facie evidence of negligence, whatever the details of Russ's crash...

Mark said...

James - I ought to point out that contrary to the sloppy BikeRadar article, Russ's counsel isnt going for a case of negligence. The point of law being argued regards the public's reasonable expectations of safety in a product under the Consumer Protection Act (1987 I think). In itself it's not sufficient simply to have realeased a safer design later to infer insufficent efforts to ensure safety in the earlier design. However, the fact that this one witness (Fox engineer and 40 degree forward drop out patent co-applicant) says that no testing was done to ascertain the effects of braking forces at the drop out area before that 2005 patent raises the question whether sufficient investigation was done at the earlier stage to meet the reasonable expectations of the public - expecially in relation to the Canondale force data, let alone the simple "right between the eyes" obvious fundamental importance of the issue. They showed a diagram in court, apparently from the Canondale study on which it was written "Max load found at axle 4,430N". I couldnt get a look at the piece of paper myself and so I'm not 100% sure it was from Canondale and from 1999, but that's what I recall from the hearing. Are you able to elaborate?

James Annan said...

First I heard about 1999 Cannondale data was your post! However, the numbers you are quoting seem pretty compatible with the 2nd half of Cannondale's tests in 2003 (bottom of this page).

Mark said...

in which case Im not confident at the timing so will remove it from my report. There was reference to 1999 in the court, but I must have misinterpreted as to what the date applied.

Mark said...

And for the avoidance of doubt, since I cannot edit my comment posted here at 11:55pm 01/11/08, the reference to 1999 above should be ignored.

James Annan said...

Ah, I wonder if that Cannondale testing may be the same thing I have then? But I don't think my copy (performed for the CPSC) mentions the axle force...the figure I gave of 3800N is my own calculation based on the torque values that were provided.

Mark said...

Its encouraging to see that your own calculations for the force at the axle are in the same order of magnitude as those mentioned in court. The figure of 4,430N was the max load recorded at the disk brake pad centre in the test exercise and written in the top left hand corner of an landscape A4 sheet with a rotor/calliper/axle arrangement diagram. The force at the axle was not specified accuratley but given the mechanical connection to the brake pads at that instant, the plaintiff counsel asked the Fox witness whether it would also imply "massive forces at the axle in the range of 3,000-4,000N" and he had to agree even without doing any calculations.

James Annan said...

OK, that sounds like it must be a different document to what I have. Mine mentions that it is part of some new testing regime that was under development, and only quotes torque values (from which it is easy enough to estimate the actual forces, of course). It wasn't really from any formalised test, just someone riding around in a car-park.

This test result was presented at Interbike in 2003 (at the ASTM meeting I've mentioned on my website), so it is hard to believe that Fox can have been unaware of these large forces at that time. Is that really what they are claiming?

Chuck said...

In other news, today British Rail has awarded a contract to Shimano to replace all their track fasteners with quick releases...
;)

Mark said...

james - my blog updated with tuesday's hearing. Had confirmation that the 1999 document was published by Hayes.

James Annan said...

Thanks! Are you going in again today?

James

Mark said...

posting this from outside courtroom. modern age eh? :)

James Annan said...

Wow. Liveblogging the trial - I feel almost like I'm there :-)

(Actually I was originally supposed to give a videoconference but they all agreed I didn't matter, which was a bit of a relief.)

I commented on your blog (first post) BTW.