Some Thoughts on Drop Outs

At the moment there is a case going through the courts where Russ Pinder is taking a legal action against Fox Racing Shox. The story behind Russ’ situation is sad and dates back to a time shortly after this website was launched in 2003. I think many of people on the UK mountain biking scene know him or feel like we know him through various conversations, fundraising events and heartbreaking stories over the last couple of years. I wouldn’t wish his injuries on anyone, even if they are a total swine.

As I see it this is a test case. It’s logical for Russ to pursue Fox as he was riding their forks at the time of the crash. The other factors in the case might be considered consistent in terms of the disc brake – it wouldn’t have mattered what brand he was using for example – the effect described by Annan would have been the same, although the forces would have varied depending on the size of the disc rotor being used.

The other factor that isn’t certain is the QR being used. There has been a lot of experimentation (although this has been real world rather than in labs as far as I can tell) and discussion to try and ascertain if this is a sizable contributing factor. The only results I have seen from this indicate that certain expensive CNC machined QRs at the time were of inferior design and function in comparison to the high leverage cams in Mavic and Shimano QRs.

On the subject of QRs I think it’s been taken as fact by those in the know (i.e those in the trade and those who actually read mountain biking literature rather than just look at pictures and listen to gossip) that using anything other than a steel axle for a QR used in a suspension fork and disc brake setup has been a stupid idea since the late 1990s. Using Titanium QR axles in this application is asking for trouble*.

The other interesting thing is that since Russ’ case and Annan’s theory getting more press, manufacturers have in many cases reviewed their designs. Fox are one of them and I think this fact may have some bearing on the case. It’s almost like an admission that they’d done a bad design in the first place. If this case leads to other manufacturers being forced to change then I think this is a good thing.

I also suspect that this case may have been a contributory factor in the design of improved bolt-through systems – particularly the lighter weight QR15 standard. This is as far as I am concerned the single biggest step forward in fork design since the original QR20 standard because it brings a no-brainer sensible design to the lighter weight fork market. I’m surprised that it has been led by Fox, rather than a company with more of a motorbike heritage like Marzocchi, but then I suspect the latter’s MTB design division is now so far removed from the Motorbike division they may not be talking to one another.

So although no one may be a winner in this, if it leads to DT, RockShox, Manitou and others to follow Fox in a sensible dropout design, be it slotted or bolt through then this is a good thing. If this is through choice or because of revised legal precedents in some of their international markets then does that really matter either? I’d argue it doesn’t because at the end of the day we as consumers will end up with a better and arguably safer product design.

Although the press may in some cases be keeping quiet on this, if at the end of it all the major mountain bike magazines run some coverage of the case, then it may make people running forks that feature vertical dropouts and in some cases no lawyer lips (either rigid or suspension) with disk brakes to consider whether this is a good idea. It might also make some smaller manufacturers think about what they’re supplying to customers paying thousands for custom built designs.

And whilst we’re on this topic it probably isn’t a good idea to use any form of roof rack that clamps the fork drop outs to the rack either. The loading stresses this invokes probably doesn’t met the general riding use the fork was designed for. Still that’s a different can of worms…

* Given the amount of Titanium components** I’ve snapped over the last 20 years makes me think that using Ti is generally asking for trouble.

** Although thankfully not frames – if my IF breaks I’ll be very sad, but happy to know they’ll repair it under warranty.

Author: Cris Bloomfield

Usually mountain biking in the North.

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