Steve Cox | February 9, 2017
The AMA Production Rule (first instituted for the 1986 season) states that any motorcycles raced in AMA Pro Racing Motocross or Supercross events must be homologated, meaning that a certain number of the machines must be available for purchase inside the U.S. prior to anybody competing aboard these motorcycles in said AMA Pro Racing events.
David Bailey’s works Honda RC 250 of the early ‘80s is one of the most iconic MX race bikes ever.
Photography by Steve Cox
And a number of things must remain unchanged from a production motorcycle even on a full-factory race machine like you see under Ryan Dungey or Eli Tomac. But in order to conserve space, I’m not going to go on and on about all of the production rules. In this column, I’m speaking purely about the chassis. This is how the chassis is addressed in the AMA rulebook:
- Frames must remain stock, as can be purchased at a dealer, along with the rear swingarm. (Exceptions are made for adding strength to these chassis members.)
- The engine-mount locations, along with the steering-head, swing-arm pivot point, and rear suspension linkage point must be the same as the homologated model.
- Subframes can be replaced, but must be made of steel, aluminum or titanium (not carbon-fiber, unless the stock machine comes with a carbon-fiber subframe), but the subframe must be of a similar design and use the same mounting points as stock.
Back when this rule was made, it seemed to make sense, as the machines run by the manufacturers—especially Honda—were so different from stock that it seemed as if nobody could compete if they weren’t on the factory team. However, the case I’m about to make in this column is that I believe the production rule—at least in terms of the chassis—may have outlived its usefulness for a number of reasons (at least in the 450cc class).
Here’s my reasoning:
This sport has taken some amazing leaps, especially over the past 15 years or so. Modern 450cc four-strokes are so incredibly powerful that even the best racers on the planet tend to detune them. Even Ryan Dungey, Chad Reed, Ken Roczen, Eli Tomac, etc., choose to have less outright power than they could have, and instead choose to try and customize how their motorcycles deliver the power.
While the motorcycles have gotten so much better, the tracks have struggled to keep up. The distances between jumps have increased since the two-stroke days simply because 450cc four-strokes can jump so much farther, and it was actually dangerous to leave the gaps the same because the racers are going so much faster through the jump transitions. Feld Motorsports and Dirt Wurx have cut down a lot of the traditional Supercross bowl turns, too. In the beginning, it was because a couple of guys ended up in the grandstands (again: higher speeds), but now it likely has just as much to do with trying to slow the racers down in general.
The problem is that today’s elite racers, on today’s unbelievably gnarly racetracks, are stressing their production-based motorcycles beyond what can ever possibly be tested prior to creating a motorcycle for homologation. In terms of the Big Four Japanese manufacturers, they do the bulk of their new-model testing with Japanese racers on outdoor tracks in Japan, or on the outdoor tracks of the MXGPs (which do not have any sort of production rules). The same is true of manufacturers like Husqvarna and KTM, whose steel chassis are almost entirely tested on outdoor tracks in Europe.
Simply put, nobody testing out these pre-production motorcycles can possibly stress these chassis the way they need to be stressed in order to guarantee they don’t do anything “funny” underneath a guy like Eli Tomac on a supercross track. When Honda spent the years necessary to develop their new 2017 CRF450R, there was no way for them to stress the pre-production stock chassis even remotely like Ken Roczen could stress it on a Supercross track.
To give you an idea of the kind of stresses I’m talking about, I’m going to tell you a quick, true story:
In 2009-2010, Kevin Windham was out at the test track with the Factory Connection team trying to sort out settings, and the team had brought two supposedly identical motorcycles for Windham to go back-and-forth between. Problem was, he kept complaining that one of the two was acting way different than the other, and he didn’t like it. The team poured over the machine to double-check everything and make sure all the suspension settings and whatnot were identical. They couldn’t find it. It wasn’t until Windham’s mechanic, Brian Calma, had the offending bike laying on its side to change the clutch, that team manager JC Waterhouse noticed that one machine had a carbon-fiber skid plate on it, and the other was aluminum. In order to control against the placebo effect, Waterhouse occupied Windham inside the box van long enough for the team to switch the skid plates on the two machines. Sure enough, the next time out on the machine Windham actually liked, he came back in after only a lap or two screaming, “Now this one’s doing it!”
That’s what I’m talking about here. None of us are going to be able to tell a difference between skid plates like that, but the top guys in the sport can literally tell if a single spoke is even a little bit loose.
When you’re on that much of an edge, and stressing the motorcycles to that sort of extent, I think the production rule—again, at least as far as the chassis is concerned—can actually be dangerous. The motorcycles simply aren’t adequately tested in that kind of environment, under those kinds of racers, and the production rule actually prevents it from happening.
What I’d like to see is doing away with the production rule as far as chassis are concerned, and even make exceptions for where the engines mount to the frames (as long as the internals of the engines still meet homologation standards), too. (After all, if Windham could tell a difference between skid plates, you bet it would make a difference how the engines are mounted to the frames, as well.)
One factory-team manager I talked to even suggested that they would be willing to make these full-factory-tested chassis available for purchase by other pro racers. But bigger than that, I think that it can only make the sport safer for regular people like us to have guys like Eli Tomac fully sussing out our production motorcycle frames in those kinds of environments.
I think this idea is good for everybody. CN
