On a motorcycle, you select a tire based on the type of surface you will be on. You will select a tire with grooves if you are going to be dealing with any road debris or water. You select a tire without grooves if you are going road racing and you are not in the box-stock class. (Box-stock has to use standard street tires).

Unless you are in the Grand Prix, you can choose from any number of tires which will give you excellent traction, and will last a long time. Some tires will not handle slides too well. Other tires will handle the slides, but they will breakaway suddenly. Other tires will stick like glue, but only last about 2 hours. Since most competitions are about 45 to 60 minutes, none of this tire selection is a real concern. Generally you will choose that which you are most comfortable with.

On a motorcross bike you choose a tire based on the terrain. Like a MTB, you can choose from the major category of HARD or SOFT rubber compounds. Unlike a MTB, you can use the wrong tire as a way to gain an edge. In other words, a soft tire is not the best tire for ALL soft terrain.
With a motorcross bike you have a larger tire cross-section than an MTB. This means that the traction and cornering characteristics are more affected by the tire pressure and the rigidity of the rim than the type of rubber you are using. Many times I would take a soft compound tire with a high amount of tire pressure. This allowed me to use the tires in the mud and water better than the guys that had a hard compound setup. Yes, I usually got smoked by everyone, but when we hit water or mud, they would always be eating my chocolate roost. This was my strategy, and it was the only way I could finish without being in 100th place out of 40 people!

So what about MTB tires?
Unfortunately technology has made MTB tires an absolute mess of options that no sane person dare attempt to make sense out of.

First the basics:
You have a choice of four basic tire types when it comes to the materials used to make MTB tires:

• Standard rubber, wire bead.
• Standard rubber, foldable Kevlar bead.
• Rubber/Kevlar compound, wire bead.
• Rubber/Kevlar compound, foldable kevlar bead.

• Soft compound, cornering. This is usually a 2.1 tire.
• Hard compound, rocks, road carnage. This is usually a 2.1 tire.
• Soft compound, multi-terrain. This is usually a 1.7 to 1.9 tire.
• Hard compound, "urban tread". This is usually a 1.9 tire.

If you consider all the possible combinations, you can see that you would need about 10 rims with the various tires and treads that you could interchange as the terrain changed. Of course, most people will not do this.

So, whaddua do?

Probably the most important thing in determining tire selection is having a place to ride which you can go to consistently. When I lived in CA, I used to go to the Campbell park and play with my tires there. Now I have a MTB "track" I carved into the field behind my house.

The point is that you need to take the bike to the same place everytime you want to learn something about your tires. Even if this is not the place you would go to "RIDE", it needs to be a place that you can go easily. Break down your decision to two factors at first - do I use a hard or soft compound, and what is the best tire pressure?

If you have a hard-compound tire, then fill it just above the minimum recommended tire pressure. Note this somewhere so that you do not have to remember. Go out to your place and ride. Note the following:

• Does the front or rear tire slide? If so, what are you doing at the time?
• Does the front or rear tire hop? If so, what are you doing at the time?
• How does the bike corner? Can you take a nice line, or do you have to fight to keep on the line. Believe me, you will know. If your hands hurt, you are probably having to fight the bike on every turn.
• What happens to the rear tire when you are pedaling up hill??

To be sure, go home, and come back another day with the same pressure and see if you still get the same results.

How to read your tires:
Front Tire: This is partially a preference thing. I like my front to predictably slide, but I do not like hopping off my line when I hit a rock or something. Either way, if your tire hops, you probably need less pressure in the tire. If you cannot do this, you probably have the wrong tire compound or the tire width is incorrect.

If the tire slides, see of you can make it more "useful" by adjusting the tire pressure. The compound is not as important here, because a slide is the best you can hope for. No MTB tire is slide proof. If you find that you are having problems only on turns and you cannot affect it with the tire pressure, then try a wider tire (2.1) or a narrower tire (1.9). Sometimes the tire profile is not correct for the rim. This can be because the rim flexes a lot, or because your wide tire is hammering on your front hub and causing the rim to spin off of a true center when you are leaned over.

If you can get the front working the way you want, you have solved about 70% of your handling problems. The rear tire is not as important. Yes, a front fork will make life easier.

Rear Tire: Personally, the only time I REALLY use my rear tire is climbing. I want my rear tire to hook up when I have to haul my bike up a hill. I also want the tire to last more than 3 rides. Either way, the rear tire selection is easier than front tire. First you have to consider the rear rim you have. If you have a 2.1 rear rim, then you should use a 2.1 tire. If you have another size, you want to EXACTLY match the tire to the rim size. DO not put a 2.1 tire on a narrow mavic rim with frenchie valves. You will find that the bike will not corner predictably. For some reason, it seems that the large tire on the narrow rim results in the tire having too much lateral movement. Thus, when you go into a corner, you will be fine to a point, and then suddenly the rear will just let go. This is because the tire is actually flexing side-to- side as you lean. At first this is not a problem, but the more you lean the more the tire gets deflected off the rim center. At some point the tire is no longer directly under the rim, and you start to slide as the tire gets farther and farther off rim center and tries to get back under the bike. Next is compound. I personally recommend a hard compound with good center tread. (Like the Specialized tire I had on the rear of my purple beast). This way you can climb to your hearts content, and you will still have a tire after the ride. Yes, there may be better setups for cornering, but this is useless when you have to climb a hill and you are sliding like whale snot in an iceflow. For cornering you will need to adjust your tire pressure. Do not let this be something you do religiously. Try to create a set of guidelines that are simple like:

40PSI: Wet, not climbing and/or climbing in soft terrain
45PSI: Dry, climbing on medium to hard terrain
47PSI: Dry, Monster rocks (protect your rim! All you have is your air!)

You may in fact wish to start with these numbers!

Tire material:
There are those which say that Kevlar tires are better for traction and thorn- proofing. Some also swear by them because of the weight. When you consider the difference in cost from a regular rubber tire, you better be sure you are getting something for the extra cash.

Foldable tires are really not all they are hooped up to be. They have the advantage of being folded, so you can take them with you on a ride. On the other hand, it seems that the flexable Kevlar bead does not work as well as the wire bead. Earlier I talked about checking your tire pressure after a test ride. If you have tires without a wire bead, you may see some loss of pressure when you are on the low end of the tires' inflation pressure. This can pose a problem on long rides. I read in one magazine where people are starting to think that tire pinching will only happen after you have *lost* some air. In other words, if your kevlar bead tires are losing air, then you are destined to true rims often, or replace the tire after a pinch-out. I believe this as it makes sense. Most of the guys here have to have serious tires that carry serious pressure. I would guess that many of them are using wire beads or I would not see them so often. We ride on rocks - big rocks. Most Kevlar tires you will see are more costly than the rubber counter- parts. Get the tire that suits you the best. Do not buy hype. Most bike shops here will recommend the ole Panaracers as the best all- around tire. Panaracers spoil you when you want to corner.

Time, Time, Time:
Yes, this all takes a while, but the rewards are well worth it. Also, knowing your limits *and* the bikes limits will help you ride faster and safer. You will also know your limits when the ca ca hits the fan. We tend to panic and do the wrong things when we screw the pooch. Wouldn't it be nice to KNOW you could make the turn instead of hitting the brakes and trying to not hit the fence OR a horse?

Flyin Al

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