Okay. I just rode over 20 miles home on my flat front tire from the trails I ride. Took over an hour to get home since could not do more than 15-20mph on a flat front. This is the second time it happened and only the thrd time I had the bike riden hard on trails!!

The first flat happened with prior owners tube. Now this second flar happened with my new tube which was a heady duty $30 tube which should not tear. But this one and the last one tore just beneath the valve stem.

Why is this happening?

What can I do to prevent it?

Is this what people say the rim lock is for if you buy one? I'm not sure what a rim lock is, but do I need one?

 

Well, one of the flats was from a torn valve stem which the rim lock should prevent. The rim lock presses the tyre bead against the inside of the rim so that the tyre doesn't slip ant pull the tube (which rips the valve off). What were the other 2 flats from?

If they are from thorns, then that's just tough luck. If it is from pinching, then it's because your tyre pressure is too low for the terrain and style of riding you are doing. The obvious solution to that is to up the pressure a bit (13 to 15 psi is a decent starting point).

If the pressures are too low, the question is why. Are you running them low for traction or for comfort absorbing sharper bumps with the sidewall flex? If it's for traction, it might be time to try a new tyre with appropriate tread for your terrain. If it's for comfort, then your compression damping in the first part of the fork stroke is too high. Try dial the compression damping out 2 clicks and see how you go. If that doesn't work, you are clearly riding the bike beyond the capabilities of the stock valving/springs... time to get the right spring strengths for your weight and riding style, and possibly even valving.

Just my 2c.

 

Offroad bikes need rim locks. Tearing your valve stem out is the evidence.

Rim Locks

 

Are you snugging the valve stem nut up to the rim? If so then don't. This will give the valve no room to move if the tyre slips on the rim some. A common mistake for those new to off road riding. Secure the nut up to the valve cap. If running pressures less than 15 PSI then a rim lock is highly recommended.

 

You can't prevent flats. Best remedy is a repair kit, if you work on it, you can get it so it packs very small.

 

I had the same problem my first year, and went through 3 tubes before I realized what it was. I run 20 psi (I think-let me check) in my front tire now, and haven't gotten a flat in 2 seasons.

 

Yep, I would agree with zomby's assessment or the necessity to run a rim lock. Higher pressure assures the tire will not slip on the rim and so does a rim lock. If you absolutely must run lower pressure, use a rim lock or you'll continue to rip valve stems.

I'll plug the Neutech Tubliss system again and again here, as I'm on to nearly two years of hard use on this system. It continues to provide excellent traction because I can run lower pressure without fear of pinch flating or dinging my rims. And with some sealant in the tire, I haven't had a flat in the whole time period...unheard of on a dirt bike run in west Texas cactus and mesquite thorns.

 

Yep, I experienced this twice on my old bike as well. The tire pressure would get low, then it would rip the valve stem out.

On my KLX, the first thing I did was back the nuts off the valve stem (just like WestOz says) and always check the pressure in my tires. After backing the valve stem nut off and running 20 psi at all times, I haven't had a flat since. Heck, go look at a new KTM, they back off their valve stem nuts from the factory.

I used to just use my hand and feel the firmness of the tires and when they got soft I would throw some air them. THAT DOESN"T WORK !!! Your tire can still feel pretty firm with only 12 psi in it and you can do some damage to it.

 

I hate flats, they can totally ruin your day. Sometimes that means a waste of 100 dollars in fuel to truck your bike to the race, plus 45$ entry fee, etc. You make an investment to ride, invest in your equipment to insure that your ride won't be ruined by a stupid flat.

I learned from experience how to eliminate flats. First, I run 20psi at all times. You get used to it and good tread is more important than super low pressure. Remember that Kawi stamped a higher psi on the swingarm for these bikes. Even 20 is lower than the manufacturer recommends. Then use the HD tubes. I installed rim locks front and rear which is required and is why there are holes in your rim from the factory. Then the last step is to run SLIME in your tires. The slime is rated to plug 1/8" punctures from the inside which should take care of your punctures and even some snake bites.

 

Don't think it has been mentioned so Ill add that you get a puncture that is not a snake bite or ripped stem, check the inside of your tire in case the object is still in there as it will puncture the tube again.