Gearing
Gearing is a rider's preference. You will meet riders who prefer and short gearing, and others who prefer a taller gearing. Are you commuting, weekend-warrior'ing it or track riding? This will all come into play when deciding on how to gear your bike.
Switching to 17" wheels will require a little math. If you want to keep the same gearing as you had with the stock wheels, you'll need to get new front and/or rear sprockets. Changing from an 18" rim with a tall dirt tire to a 17" rim with a low profile sportbike tire will change your gearing 10-15%, so you need to adjust accordingly with the proper sprockets.
Your speedometer and odometer will also be out of calibration if the speedo drive is off the front hub. There is usually no way to recalibrate the stock speedometer to account for this, so you either have to do some mental arithmetic while riding or install a digital bicycle speedometer that can be calibrated for the new rolling circumference.
Tires for SuperMotos
SuperMoto street bikes usually use sticky sportbike tires, or SuperMoto Specific Tires. The most common sizes are 120/70x17 for the front and either 150/60x17 or 160/60x17 for the rear. The 160 size looks "meaner" in the rear, but many bikes can't handle that size due to interference with the chain. It's not uncommon to actually "shave" the edge of the tire on the chain side to provide some clearance, but for most people the 150 size will fit and actually handles better.
Why do the 150's handle better? This is mostly due to the commonly used 4.25" rear rim width. The 160 size is simply too wide for the rim, and because it's not designed for that size rim the profile gets distorted. The distorted profile results in what is actually a smaller contact patch than the 150 gets on the same rim. The 150 will grip better and turn in easier. Still, the 160 has a poseur factor that many like. I use a 150 on my SuperMoto because the performance is more important to me than the look.
Tire Types
SuperMoto racebikes usually use racing slicks that are custom grooved at the track for the particular conditions of the track they'll be racing on that day. Slicks are illegal on the street though, so please use DOT-legal tires on your street bike!
Sportbike Tires
Until quite recently, most street SuperMoto riders used sportbike tires like the Michelin Pilot Powers, Dunlop D208, Metzeler Sportec M1, or Pirelli Diablo or Diablo Corsa. Those tires are designed for sportbikes with their higher weight, horsepower and speeds. Who needs a 150MPH rated tire on a bike that will seldom see over 80MPH? SuperMotos often have a hard time getting them up to the temperature where they work best.
Rain Tires
Another popular choice is DOT-legal rain tires such as the Pirelli MT60R and MT60RS and Avon Pro-Extreme AV49/50 Rain. Some folks like them because they work a bit better in dirt. Not surprisingly, they are also absolutely awesome in wet / rainy conditions, so if you ride in the rain a lot you might want to consider them.
Rain tires are very soft and sticky, but unfortunately they wear out quickly on dry pavement. I got less than 800 street miles out of an Avon rain rear tire before it was almost bald and had lost much of its grip through excessive heat cycling. They're also pretty expensive and usually not available at your local dealer.
SuperMoto-specific Tires
Earlier, I noted the problem with the more heavily constructed sportbike tires. They're overbuilt for SuperMoto use, relatively heavy and hard to get up to proper temperature on a SuperMoto. Fortunately, due to the increasing popularity of SuperMotos on the street, some manufacturers are starting to produce SuperMoto-specific tire models.
These tires are usually "H" rated (130MPH), use stickier rubber compounds that come up to temperature more easily, and use a more flexible and lighter carcass. The lighter weight is important, because tires are "rotating unsprung weight". The more of that you have, the slower your bike can change direction, accelerate and stop.
Two examples of these new SuperMoto-specific tires are the Avon Distanzia in 120/70x17, 150/60x17, and 160/60x17, and the Continental Contiforce (available in the same sizes as the Avon).
Note that there may be confusion at your dealer about Distanzias. Until very recently, Distanzias were manufactured and marketed as a high mileage dual-sport tire. All of them except for the H-rated 120/70x17, 150/60x17, and 160/60x17 sizes still are. Rest assured that if you buy one of those three sizes in the H-rated version, you are getting the soft, sticky SuperMoto version I've described here.
Both the Contiforce and Distanzia are available from Motostrano and other tire vendors.
Tubes
Although all the popular SuperMoto tires are tubeless (ie: designed to be used without tubes), if you run them on spoked wheels you will most likely have to use tubes in them, because normal spoked wheels would let the air leak out around the holes where the spokes enter the rims. Tubes in the proper sizes for your SuperMoto should be available wherever you got your wheels.
There are currently some alternatives to using tubes. One company has tubless spoked wheels under development, but I don't believe they are for sale yet. You can also get a kit from Motostrano that will convert your spoked wheels to tubeless.
Before leaving the subject of tubes... because the spokes can abrade your tubes and cause flats, it's common on dirtbike wheels to use "rim strips", which are like big rubber bands with a hole in them for the valve stem. They go around your wheels and cover the ends of the spokes. It can be difficult to find rim strips of the right size to cover the spoke ends on the wider 17" diameter SuperMoto wheels, though, and because of that most people just use a couple wraps of duct tape around the rim instead. It's cheap, and it works... but if you don't do something, your spokes will tear up your tubes.
Brakes for SuperMotos - Lose the Dirtbike Brakes!
SuperMoto conversions are usually based on dirtbikes (enduros or motocrossers), and those bikes have woefully inadequate front brakes for SuperMoto use. Dirtbike brakes are designed to be weak and lightweight, because it is much easier to lock up your brakes in the dirt. On a SuperMoto, those brakes will overheat and fade in spirited riding conditions. So, if you are converting a dirtbike, you need to address upgrading at least the front brake. Also, good braking systmes is what allows SuperMoto riders to "back-it-in" (or slide the rear into a turn), which is defining riding style of these motorcycles!
Upgrading Your Front Brake - Using Your Stock Caliper
The cheapest way to upgrade your front brake is to use your stock front brake caliper with a bracket that offsets it so it can be used with a large rotor. 320mm rotors are the standard for SuperMotos, and they usually just use one, mounted on the left side. Manufacturers such as Motomaster and EBC offer kits containing an oversized (320mm) rotor and a billet aluminum offset bracket. These kits run from around $150 to almost $400, and are really quite adequate for street use as long as you use good DOT4 or 5.1 (not DOT 5!) brake fluid, stainless steel brake line and give it a good bleeding job.
Race Grade Brake Systems
For maximum braking power, you can install kits that include a 4 or 6 piston caliper (most stock calipers have only 2 pistons), a full floating 320mm rotor, and sometimes even a radial master cylinder. They're manufactured by such names as Beringer, Motomaster, Brembo, and Braking USA, and can be purchased through the suppliers listed on our Suppliers page.
These setups are much more expensive, and run in the $600-$1000 range. In my opinion, brakes like this are gross overkill for street SuperMotos, but they are definitely ultra high quality, have a huge "bling factor", and they will truly give you the capability for one finger stoppies. Just be careful and don't grab a big handful in a panic, or you will quickly learn just how well SuperMotos survive crashes. I recommend riding with one or two fingers covering the front brake lever so you aren't as likely to grab with all four fingers.
Brake Pads
You can further improve your braking power and "feel" by upgrading your brake pads. The high-end braking systems usually come with very good pads, but if you are using your stock caliper I recommend installing a set of EBC"MXS" sintered metallic pads. They provide more initial "bite" and better stopping power than the stock pads. The good news is that they are cheap (about $25) and easy to install.
Stainless/Kevlar® Brake Lines
Stock rubber brake lines can make your brakes feel mushy and soft even when the system has been properly bled. This is because under the stresses of hard braking, the rubber lines will actually expand, wasting braking power. I am a firm believer in upgrading your brake lines to use either braided stainless steel or Kevlar® lines that don't expand under hard braking. These lines are made by such companies as Galfer, Spiegler and Goodridge, and are available from the suppliers we've listed.
Make sure if you get braided stainless lines that they are covered with a plastic coating, because the stainless steel lines can act like a file and saw through things they rub against. I think nowadays all of the stainless steel lines have a coating on them (and you can even get them in different colors), but make sure the ones you buy have the coating / covering. Kevlar® lines don't have this problem. Once you try good brake lines, you'll never want to use the stock rubber ones again.
Brake Fluid
You should routinely flush your brakes and replace your brake fluid (once a year is a good interval), but most people don't. Brake fluid is "hygroscopic", ie: it absorbs water out of the air. That's why new brake fluid is usually a light amber color and old fluid turns black. As it absorbs more water, it gets darker and darker. When brake fluid has absorbed water, the water can actually boil in your calipers when they get hot under heavy braking conditions. When this happens, the water turns to steam, and steam is compressable (brake fluid is not), and you'll lose either some or all of your braking power just when you need it most!
OK, now that I've scared you into paying attention to your brake fluid and you're going to change it (you'll need to do this anyway when you install your new brake lines), you need to buy good fluid. First check the manufacturer's recommendations for your brake system and use what they specify. If they don't specify, use either DOT 4 or DOT 5.1 fluid from a new, sealed container (brake fluid will even absorb water from the air inside a closed container that's been sitting on the shelf). Do not buy DOT 5 brake fluid unless that is what the mfg of your braking system has specified. DOT 5 is silicone-based, and while it is not hygroscopic, it is not compatible with DOT 4 and DOT 5 fluids. Don't use it!
I'm not going to go into the specifics of draining and flushing and bleeding your brake system, as there are plenty of resources about that on the web. The important thing is to do it... don't ignore your brakes!
Rear Brakes
You can do all the things mentioned above to your rear brakes too (with the exception of using a 320mm rotor), but aside from flushing and bleeding them and making sure you have good pads and the above mention brake lines. More and more SuperMoto riders are starting to hone their rear brakes as much as their front brakes.
Accessories
Assuming you have already done the basic conversion of your dirtbike into a SuperMoto, there are some additional items you might want to consider adding or changing.
Front Fender
Standard front fenders on dirtbikes are well-designed for riding in the dirt and the muck. They're long and wide and are contoured to go above a 21" wheel. Problem is, they are really ugly on a SuperMoto bike with a 17" front wheel. Several manufacturers such as Acerbis, Maier and Cycra now make front fenders that match the stock plastic colors, but are shorter and are contoured to work with the 17" wheel.
Crash Protection
Let's face it... SuperMotos bring out the hooligan in all of us. When you start riding one, you'll be tempted to do wheelies, stoppies, backing it in to a corner, and generally going pretty fast. You'll become addicted to spanking sportbikes on goat trails. And at some point, you'll probably crash. SuperMotos do crash well, but there are some items you can install that will help to protect it even more.
Handguards
Your hands are very vulnerable in a crash. There are stories of riders getting their hand pinned under a handlebar end and sliding to the extent fingers got ground off. That's NASTY! You can provide some good protection for your hands by installing handguards on your handlebars. They cover your hands and levers in the event of a crash and protect them both as long as you remember to hang onto the grips when you go down.
Sliders
Sportbikes use frame sliders, and SuperMotos can use sliders too. At a minimum, you should consider axle sliders. Axle sliders will keep the ends of your forks and your swingarm from getting scratched up if you lay the bike down. Many racing organizations and tracks are REQUIRING the use of sliders for SuperMoto bikes due to the damage these bikes cause to the pavement as they are crashing. Don't be cheap... just get them!
Skateboard Wheel Sliders - There are two basic types of axle sliders. When SuperMoto first started getting popular, some bright soul figured out that by affixing skateboard wheels to the ends of his axles, he could provide some crash protection. If your axles are hollow (most are), all you need is 4 skateboard wheels, some washers and nuts, and a couple lengths of threaded rod. You stick the threaded rod through your axles and mount the skateboard wheels on both sides with nuts and washers. It works, but I think they're cheesy looking, and the nuts and threaded rod tend to be good for only one crash before they're all bent up and scratched.
SuperMoto Engineering Axle Slider - The hot setup is a set of the neatly designed sliders from SuperMoto Engineering. These sliders are lightweight and very strong. The slider component is made of Delrin®, which is a very tough yet slippery plastic material. They use stainless steel threaded rod and gold anodized aluminum nuts and spacers. The nuts are recessed so they don't get torn up if the sliders hit the ground. Yes, they cost more than the cheesy skateboard wheels, but they really work well (don't ask me how I know this).
When you crash (notice I said "when", not "if"), the parts of your SuperMoto that hit the ground are usually the front fork ends and rear swingarm & axle, your pegs, and the ends of your handlebars. SuperMoto Engineering has sliders for all those points of contact.
SuperMoto Engineering Peg Slider - They're made of the same materials as the axle sliders, and will protect your footpegs. They also provide a great sliding surface when you are at extreme lean angles. I've seen many "peg-sliderless" riders crash from gouging their peg into the pavement.
SuperMoto Engineering Bar End Slider - Same materials again, and they are available in black or white. These'll save wear and tear on your handguards and handlebars.
Radiator Braces
If you have one of the SuperMotos with a liquid cooled engine, your radiators are vulnerable in a crash and they're very expensive to replace if they get torn up.
Fortunately, Works Connection has the solution for you. Their stainless steel radiator braces will reinforce your radiators and keep them from getting folded up when you crash.
Misc. items
There are many dress-up parts that SuperMoto riders like to purchase. Acerbis Headlights, graphics kits, Clarke/IMS large capacity fuel tanks, big handlebar kits, etc. These are all available through your local shop.