Friday, October 22, 2010

Bad tread streak

Can anybody identify this object? It is about the size of a quarter.

It is a growth of sorts.
It is not a cat brain.
It is not cauliflower.
Nor a cancerous tumor.
It isn't even biological.
Give up?

Riders who run Stan's sealant in their tires have probably seen these before. These are the growths that seal around leaks in tubeless tires. It seems once a leak is plugged and there is a wad of Stan's there, it just keeps growing.

I've had an exceptionally bad season for tires. I've nearly gone a whole season without a road flat before. Now I'm making up for it.  I've suffered four road flats since coming out of my cast in July. Two were the result of hitting things. One was several weeks ago when I hit a submerged pothole in a rain storm. Today I don't know what I hit. Had my head down going into the wind, when suddenly both hands were nearly ripped from the bar and the rear wheel kicked over a foot. I momentarily skidded. Very close. Thought for sure that was good for a double flat. Had no idea what I hit. It must have flown off into the ditch, as there was nothing there when I looked back. I soft pedalled for a bit, bouncing on bike, fully expecting a squishy tire or two. Seemed ok. But a minute later I got that squirmy feeling in the back. While changing the tire along busy Continental Blvd, the wind blew my bike over, the wheel tipped while I was pumping it, driving my knuckles into the cassette, then I could not pull off the pump nuzzle and completely broke off the presta valve nut. I carry only one spare. Amazingly, it held air for the three miles back to work.

Off-road, I've had two failures in the last couple weeks. I noticed on my Dean hardtail a 1" long slice in the rear tire where some Stan's had leaked out. Have no idea what ride this happened on, it was proably that way when I did a 50 mile loop last weekend.  It was this tire the Stan's tumor above came out of. I plan to ride that bike this weekend while waiting on dualie fork parts. The tire was cut so badly I didn't trust it and put a new one on. I have a bunch of WTB Mutanoraptor UST tires on hand I bought for $19.95 each. The Mutanoraptor's go on easily without using a lever and inflate readily with a hand pump.

While riding my Superfly in Mine Falls on Wednesday, I went through the gnarly section by the dam pretty hard. I ran the onion skin Stan's Raven tires pretty soft and felt them bottom out hard a few times. Sure enough, when I popped out in the parking lot by the dam, I heard the tell-tale sign of psssssssssss. I pinched through the rear sidewall. For the first time ever riding tubeless tires, I went into a frantic shake the tire around routine to get Stan's sealant to plug the whole. It worked just in time, but I had to re-inflate the tire. I was skeptical of those tires to begin with and had ridden them only one other time. They are wicked fast on gravel and hardpack, but I doubt they would have gotten me to the finish of the Ironcross race without a catastrophe. Spent big bucks on them, now I don't know what to do with them. The Raven's are "Tubeless Ready," not UST certified tires. This means the side walls are super thin and porous and sealant is require to hold air. In the last six years, I've never flatted or burped a UST tubeless tire. It's a love hate thing. Full UST compliant tires are heavy and often not the fastest rolling tires, but they so friggin reliable.


Paul said...

So these tyres don't have the official UST bead, and have highly porous sidewalls. How can they be "tubeless ready"? Isn't that blatant false advertising?

To put it another way, isn't every tyre ever made "tubeless ready"?

As an engineer, nothing Stan's has ever done impresses me. Sticky tape and goo is not a good solution.

Hill Junkie said...

I swear by Stan's sealant in UST tires. I haven't had a flat on the trail in many years, and that includes many trips to Arizon, the cactus capital of the world.

"Tubeless Ready" implies that the tire bead has a modified shape to it and the bead reinforcement is stronger than a traditional tire. Many traditional tires do not work in a tubeless configuration, as the bead breaks seal frequently, called burping. The idea behind tubeless is to run low pressure such that the tire can pinch to the rim and there is no tube to flat. You get better traction. Weak bead designs are not compatible with tubeless setup because the bead does not stay put at low pressure. It is understood that tubeless ready means you MUST use sealant, while it is optional with a UST tire. I have never run UST dry. Not worth it. For tiny amount of weight, any puncture, up to screwdriver size, will seal quickly.

The Bontrager tubeless ready 29-3's I used for a while seemed like a pretty reliable tire. They are sluggish climbing hardpack though. That is why I opted for the minimalist tread Stan's Raven tires for Ironcross. Most buyers of this tire understand it is a limited use tire, not suitable for typical New England gnar. I pushed it a bit outside its useful envelope. It would have been risky to used at Ironcross, as there's a gnarly 2mi singletrack descent in the course.

Anonymous said...

The trilogy theory of bike components states good parts can have only 2 of the following 3:


Hill Junkie said...

I guess the Stan's Ravens don't even pass this metric; they are neither durable nor cheap. The only thing they have going for them is their lightweight construction lets them roll with minimal resistance.