KDXRIDER.NET

What a bummer!!, this past Sunday I had my 17 year old son race single track for the first time on his '06 KDX200 (so please bear with me as we're beginners at this racing stuff). His bike has the kx fork conversion & most of the mods suggested by you guys in this forum with the exception of the RB head & carb mod. He got out 2nd on the start & kept that position for an hour (the race lasted hour & a half) until he got a flat ending his chances to finish. It was a rocky terrain & we were running 15 psi front & rear (although I have to say we were running a standard tube so most likely it was a rookie mistake on our part). Can anyone give us some directions as to what can we do to minimize flats?. Any help will be greatly appreciated.

Thanks,
Roger

A few suggestions:

• -More pis (ride and traction will suffer however)
  -Heavy Duty Tubes
  -Talcom powder on tube
  -Old tube slit and wrapped around new tube
  -Avoid rocks

Bummer on the flat.

Here is my opinion, and what works for my terrain where we have few rocks but lots and lots of roots.

I run those super heavy tubes. They aren't just thick, they are really thick!
I use duct tape instead of the rim liner.
I make sure the rim lock is in good shape.
I leave the rim lock nut loose until the tire is mounted and inflated and the bead set. I tighten the rim lock down last.
I leave the valve stem nut loose and run a bead of silicone around the valve stem and the rim lock bolt. I'm trying to keep gritty water from getting in between the tire and tube.
I run 8 psi front, 8-1/2 rear. Any more than that and traction and handling go to sh&t.

I haven't got a flat in a long time. I used to get flats using standard tubes from the valve stem getting torn off or grit scuffing a hole through the tube.

Despite the prevailing internet wisdom, 8 psi front will not result in a pinch flat on my bike. 15 would be slip and sliding around.

Bridgestone Ultra-Heavy-Duty Tubes are the thickest and toughest tubes by far. There are others (Moose, Micheline, etc.) but they all cost about the same, and the Bridgestones are superior. After a while you may here something rolling around in them. That is the rubber as it gets balled up inside. Don't worry about it. Tire changes will be a bit tougher, though.

The wheel had:
-the powder
-duct tape
-wheel lock & valve stem loose until the the tire was mounted & inflated

So what I gather is to keep the above & add:
-Old tube slit and wrapped around new tube (I've heard that one before)
-I leave the valve stem nut loose and run a bead of silicone around the valve stem and the rim lock bolt. (This is a new one for me. Makes sense though 'cause when I usually remove the tube, the stem area is rusty)
-Run 8 psi front, 8-1/2 rear. Any more than that and traction and handling go to sh&t. (Have you tried this pressure on rocky terrain?. I mean, I wish i could run this with no problems).

Thanks for your prompt responses!
Roger

what about a bib mose, or whaterver that foam insert that takes the place of a tube is???

Tubliss

tennis ball...

scheckaet wrote:tennis ball...

yea!!!!!!!!! tennis balls. how many does it take for a 21" wheel?

I run ultra heavy duty tubes and I change them out with a new one every tire change. Some people say they are harder to install but I've never noticed any difference. It's all in your technique

I usually always run 10 - 12 psi

in 8 years Ive had 2 flats on the KDX

When I can afford it, I'm going to go tubliss

i run michelin comp 3 & 4 tyres as these have a good strong carcass ..combine these with a `ultra` heavy duty tube along with tyre slime or gloop (puncture preventitive) & you can rest assure you`ll be able run a low tyre pressure between 10 - 14 psi without the fear of a flat....bib moose are expensive & dont last more than a tyre change or two before they start to break down due to chaffing inside the tyre/rim..if you can afford this expense then they are the solution to your puncture probs, if not then stick with a good tough tyre with a heavy duty tube & run the tyre between 12/15 psi on stoney/rocky ground depending on your weight..

Ultra HD TUBES or go TuBliss

I have been using TuBliss for two years. I got one flat and was able to finish the ride no problem. Now I use TuBliss + slime.

Thank you guys for all the responses!

-Run 8 psi front, 8-1/2 rear. Any more than that and traction and handling go to sh&t. (Have you tried this pressure on rocky terrain?. I mean, I wish i could run this with no problems).

A couple of enduros north of here are pretty rocky and I had no problems.
When scootng along I doubt the tire can tell the difference between a 4" root or a rock.
Tire pressure has a lot to do with rider/bike weight, also. I'm only 170 lb.

I judge good pressure for me by a few measures:
Good traction
Good handling
A 1/8" to 3/16" wide shiny band on the rim right at the tire bead. That tells me the tire is flexing and conforming.

A couple of pounds can make a big difference. A good tire gauge is hard to find. I made one out of a 0-20 psi mechanical gauge