Buell’s Firebolt radical? We’ve seen it all before

When Buell released its new Firebolt two weeks ago, it came with a host of unusual features. But how many of these are actually new? Is the bike a radical machine bristling with 21st Century concepts, or just a rehash of old ideas?

More importantly, do Buell’s concepts actually have any real benefits? Are they the sort of things we can expect to see other firms copying, or are they so outlandish that ” sensible ” manufacturers like Honda have already written them off as a waste of time?

One of the most striking things about the Firebolt is its massive aluminium beam frame. Nothing new here – most modern sports bikes use them. What is new is that the Buell’s frame also doubles as a fuel tank, while the engine oil is stored in the swingarm.

But according to Bob Stevenson, boss of British engineering specialist Spondon, storing fluid in the frame isn’t that radical. He said: ” We’ve been putting oil in frames for years now. I see no reason why you can’t do the same for petrol. ”

In fact, the idea was used in speedway bikes way back in the 1950s, when famous frame builder Mike Erskine experimented with putting the fuel in the frame. The idea never caught on, even though his bikes won races.

But why would you want to? The main reason is weight distribution. On the Buell, the fuel and oil are both located near the swingarm pivot point, helping keep the centre of gravity low and working to counteract the marque’s traditional top-heavy feel, caused by its upright, heavy V-twin motor.

The firm’s boss, Erik Buell, said: ” It enables the very tight packaging and compact dimensions of the bike. Putting the fuel and oil anywhere else wouldn’t allow it to be as compact. ”

Steve Harris, of tuning firm Harris Performance, thinks the idea could take off. He said: ” Design is heading towards parts with more than one function. Automotive design is featuring more in bikes. The car people think very laterally. The motorcycle industry traditionally does not. Automotive designers think nothing of ideas such as fuel in the frame, and modern casting processes are now making it possible. ”

However, Harris isn’t as sure about the idea of putting the oil in the swingarm. He said: ” You want to keep the unsprung weight as low as possible, I think they would have been better advised to keep the oil reservoir in a more conventional position, but as it is near the swingarm pivot it may be OK. ”

Another aspect of the new Buell that is sure to attract attention is the rim-mounted brakes. This is the first time the design has made it to a production bike, despite appearing on race bikes and hundreds of concept bikes over the past few years, so they really are at the cutting edge.

Because there is a greater diameter at the rim than at the hub, the discs can have a larger surface area than conventional ones. This provides a larger contact area for the pads, boosting stopping efficiency. It also means they cool down more quickly. In addition, the braking forces are transferred directly into the rim and not through the spokes, so the spokes can be made less braced and therefore lighter. This reduces the wheel’s weight and the gyroscopic forces acting on it, meaning the bike turns quicker.

But V&M Racing boss Jack Valentine isn’t sure it’s worth the effort. He said: ” They will work very well and will certainly get people interested, but the benefits for road use are marginal. ”

Another part of the new bike that will make an immediate impact is the geometry. With a wheelbase of just 1320mm and a 21° head angle – 75mm and 3° less than the R1 – some people have voiced concerns about its stability.

” It will be a lively ride, ” admits Harris. ” It is a very short bike, but Buell will have done its homework, so it shouldn’t be too bad. I bet it wheelies well! ”

Jack Valentine agrees. He said: ” It will be sporty, but the wheelbase shouldn’t cause any problems. The smooth power delivery will help stability. ”

Buell reckons he’s on to a winner. He said: ” Once you’ve ridden the Firebolt, you’ll see how the innovative engineering really works. ”

We’ll have to wait until our first ride in October to find out if he’s right.

There’s more on this in MCN, on sale on Wednesday, August 8, 2001.