Originally Published in the IAMC Newsletter, June 2013
Editor’s Note: The following is reprinted with minor revisions by permission of the author, Bill (aka BannerUp), from ThumperTalk at this link: http://www.thumpertalk.com/topic/671886-tire-selection-guide/
You’ve installed new springs to accommodate your weight and riding style, adjusted the preload, and spent three weekends out in the rocks and roots getting the compression and rebound dampening just right, then your buddy says you’ve got the wrong tires. Hey, maybe he’s right. What good are all those performance and handling modifications if the rubber that puts them on the trail isn’t getting the job done?
The number of brands, models and styles complicates choosing the “right” tire. It’s enough to boggle your mind. In the old days, tires were like ice cream, they came in three flavors: street, knobby or trials. Today, there are a lot more than 31 flavors, and trying to simplify your decision by visiting a tire-talk forum is like tuning into a “Church of Tires” broadcast. But there are criteria for making the right choice. Here’s a four-step process for finding a new pair of shoes for your bike and riding style. It won’t eliminate some trial-and-error, but it will help minimize poor choices:
Step 1: Understand the General Rules of Thumb…
- Knobbies provide more traction and are less prone to flats than street tires in off-road terrain; But some DOT approved dual sport tires work quite well in off-road situations;
- Trials tires provide more traction than knobbies on just about everything;
- But most feel wishy-washy on paved or hard-packed roads unless you pump them up;
- The more technical a trail becomes, the more a trials tire will out perform a knobby.
- Tires with soft rubber provide more traction but do not wear as well as hard-rubber tires;
- Wide tires provide more traction and straight-line stability than narrow tires, but less steering precision;
Step 2: Understand the “Knobby Versus Trials” Rules of Thumb…
Most off-road bikes work best with knobbies, but some riders have mounted one of the modern radial-ply trials- type tires for superior handling in certain conditions. The more technical a trail becomes, for example, the more a trials tire will out perform a knobby. With more power getting to the ground, a stock 250 can feel like a 300, and that’s good news! It’s controversial, of course, and perhaps always will be, but here are some things to consider when you’re looking for a new set of shoes…
- Knobbies get their “bite” by digging into the ground and pushing;
- Trials tires gets traction by wrapping itself around the rocks and roots and rolling over them;
- On slippery surfaces, such as dry weeds, wet rocks and pebbled roads, a trials tire flattens out more than a knobby to give you a better bite — the more “technical” a trail becomes, the more a trials tire will out perform a knobby.
- Trials tires do not, therefore, break loose as easily or as predictably as a knobby, so you probably would not choose one for sliding around corners or for any situation where you need some wheel spin
- But a rear trials tire will break loose in a more predictable and controlled way with a trials tire on the front, because the front will remain more firmly planted while you’re swinging the rear through a turn
- You should adjust your suspension to be stiffer for a trials tire than you would for a knobby
- Since trials tires flatten out more than knobbies, they give the rider more “cone effect” in turns. Take a paper cup — small at the bottom and large at the top. Toss it on the ground, and give it a kick. See?
- Knobbies have a stiffer sidewall, and therefore provide more protection against flats due to a slashed sidewall than do trials type tires
- But you can minimize “pinch” flats in a trials tire by installing a tubeless trials tire (which has a stiffer sidewall than the tube models) with a heavy duty tube, such as the 4 mil Bridgestone Ultra Heavy Duty tube
- You can use as little as 6-9 pounds for maximum traction, but 10 lbs is recommended to minimize flats
- Trials tires are easier to mount than a knobby, but the bead comes off the rim quickly with a flat — you won’t be riding back to camp on a flat trials tire, so be prepared to replace the air by one method or another.
- Keep a close eye on your spokes — the more flexible sidewalls on a trials tires seems to put more forces on the rim and accelerate loosening of spokes.
- Keep a close eye on the valve stem. Install the tube so the stem leans forward slightly when at the bottom position. If you notice it leaning backward, your tire is slipping on the rim. Try a wider rim lock or insert a small strip of inner tube between the bead and rim at the rim-lock location.
- Trials tires do not handle big whoops as well as knobbies do, and some are “squirmy” on paved or hard-packed roads, so they’re not the best choice for desert or dual sport events with easy trails and occasional highway riding.
- The trials tire with the best wear has the best traction but the worst side knobs and the least overall knobby feel…
Step 3: Compare the Rules with the Characteristics of Specific Tires…
Visit the websites of off-road tire manufacturers and browse through the different models they offer. Check out the fitment guide at each website for your bike, model and year — sometimes those guys at the factory really do know what they are talking about. Most tire sites provide a picture of each tire with a brief description of its intended use, but Michelin makes it even easier by providing a chart for each of its tires. Here’s the chart for one of their enduro tires…
BRIDGESTONE… http://www.bridgestone.com/products/motorcycle_tires/
CONTINENTAL… http://www.conti-online.com/generator/www/de/en/continental/motorcycle/general/home/index_en.html
DUNLOP… http://www.dunlopmotorcycle.com/default.asp
IRC… http://www.irc-tire.com/mce/top.html
KENDRA… http://www.kendausa.com/en/home/motorcycle.aspx
MAXXIS… http://www.maxxis.com/MotorcycleATV.aspx
METZLER… http://www.metzeler.com/site/us/
MICHELIN… http://teammichelin.com/
PIRELLI… http://www.pirelli.com/tyre/ww/en/motorcycle.html
SHINKO… http://www.shinkotireusa.com/
And here’s a chart to help you understand those designations on the sidewall of the tire…
Step 4: Visit Tire-Talk Forum and Read the Rider Reviews…
AMA: http://www.americanmotorcyclist.com/Riding/Street/Resources/TireDesignations.aspx
WEB BIKE WORLD: http://www.webbikeworld.com/Motorcycle-tires/tire-data.htm
PROCYCLE: http://www.procycle.us/info/guides/wheels-tires/tire-information-0211.html MOTORCYCLE.COM: http://www.motorcycle.com/rider-safety/motorcycle-tires-101-91339.html
Editor’s note: This article is republished by permission of the author, Peter Jones, and originally appeared in the September 2007 issue of Cycle World, pp. 72-73. For many it captures the inspiration of motorcycles and sums up “the why of riding.”