Streetfighter Motorcycle Frame Designs

In the wonderful world of Fighterdom, you are onlyto the engine mounts. Honda has also adapted this
limited by your imagination. In the grand scheme ofstyle frame on their Hornet line. This setup is not only
things, we are working with 3 main elements: thevery rigid but also allows to showcase the engine.
wheels, the engine and the seat. The way in whichThe down side is the frame has to go over the
these elements are connected, to work as a whole,engine witch can make the bike rather tall.  
are practically limitless. Chassis design, suspensionTwin-Spar or Twin-Beam Frame:
components, and body design are all key factors ofThe twin spar or twin beam frame is one of the
what makes a motorcycle unique. Each part that ismost commonly used frames among sportbikes. If
assembled with the machine not only adds in itsyou've owned a GSXR, YZF, CBR or ZX of the last
function but also to it's style.10 years you've ridden a twin spar. They are very
One thing that has always intrigued me was framerigid, and strong frames. They can be heavy and
design. With out a frame we basically have a pile ofbulky compared to other examples but in recent
random parts, but there's more to it then just ayears the manufacturers have come up with new
place to bolt it all together. This is the beginning andtechnologies to help cut the weight while still
end of how well your bike is going to perform. Youmaintaining the strength. Arguably not the prettiest
can put the best suspension, biggest brakes, andof designs but can be made to work as eye candy if
lightest wheels you can afford on your bike, but ifdone well. Another advantage of this design is the
the frame is weak and twitchy all those killer partsability to hold or hide some of your components or
are for nothing. In the day and age we live in, it'sfluids. Case in point the Buell XB series with its fuel in
hard to beat the quality and construction of theframe design.
latest and greatest factory superbikes. Let's face it.Monocoque Frame:
They have the time and money to put all the R&DOne of the most unique designs is the monocoque.
and design into them they want until you have aThis can be done a number of ways. A number of
super light, super rigid frame. Now that doesn't meanpanels that bolt together, tubes that mount in
we have to swear off the idea of designing our own.triangulated shapes, even just bolting everything to
This is kind of the crème de la crème of building athe engine. It's a complex structural design that pulls
special. A truly one off frame separates the menthe machine together in a very unorthodox way.
from the boys so to speak. For those of us withAs for materials these frames can be made from,
older bikes this can greatly help overall performancethe range is also large. Steel and aluminum being the
and handling by making the bike much more sturdymost common, although there are examples that
and responsive. But also on a styling note this ishave been made of carbon fiber, stainless steel and
where you can really start laying out the look of atitanium. All these materials require a certain amount
bike. The chopper crowd has been stretching andof skill to work with. Steel is probably the easiest and
raking frames for decades. This was for a mater ofcheapest although is the heaviest of materials. The
style. But when you start building your own frameup side is it is the most resilient to flexing forces and
you can make it all work together. You can have theif designed right can weigh in very close to an
style and performance in one package.Aluminum frame. Aluminum would be next up the
Different Streetfighter Motorcycle Frame Designs :scale but takes more skill to work with. Welding
Trellis Frames:aluminum can be tricky. It melts faster then steel and
For those of you that have been around the fighteryou have to have a good working knowledge of this
scene, you no doubt have seen the beautifulmaterial for it to weld right. It is very rigid and strong
examples built by Spondon, Harris, RAU and some ofthough and also half the weight of steel to gain the
the later builders such as Martek, Steelheart andsame strength. Titanium is very expensive and hard
PEST. The most common design of these frames isto get in large quantities but is the lightest and
a trellis format, similar to Ducati and MV Agusta. Builtstrongest of the more common metals. Carbon fiber
from either large diameter aluminum tube or chromolyis also getting harder to get and requires a totally
steel, they offer a very light and rigid construction,different set of skills to work with. It also requires
but also give the builder a range of adjustability inquite a bit to gain the same strength as the
component placement and over all layout. Mountingaforementioned metals. It is brittle though and has
points can be made to fit many different enginebeen known to shatter under the right forces.
configurations and also allow for a range ofSo how do we lay all this out and make it work?
suspension locations.  Well, like I said earlier, that's what you have to figure
Backbone or Cradle-Style Frame:out. I will say this. Start drawing lines from the
The next form of frame configuration is thesteering head to the swingarm pivot and go from
backbone style or cradle frame. Most commonlythere. Look at some new bikes and how they are
found in older bikes and traditionally styled cruisers.laid out. Specifically, look at there mounting points;
RAU has adapted a version of this to act as asteering, engine and rear end. Break out your
stressed member frame. Instead of a full cradleimaginary pen, A.K.A. your finger, and start drawing
frame that has mounting points for the engine to sitlines from one point to another. I'm interested in
into, they use the engine to mount the frame. Thiswhat you'll come up with. There's a lot more to this
style does away with the lower frame rails. Itas well, such as component positioning, center of
incorporates a large diameter tube for thegravity, rake, trail ride height etc., but we will attack
"backbone" and a section of down tubes to connectthese issues another time!