Ultimate puncture proof bike tires? testing Kenda K-shield and K-shield Plus

Just FYI on the Kenda Drumlin Cargo.

I have 150 cumulative miles on these tires and have picked out a few dozen goathead spines, and no flats so far.
Seems like the body of the goathead broke off in all instances except 1 where it was on the side of the tire.
I believe the hardness of the tire might be helping.

I have yet to see any goatheads longer than 7mm so far. No 11mm monsters yet. I'm actually kinda disappointed.

Will continue racking up the miles until it gets too cold to ride

neptronix said:

I have yet to see any goatheads longer than 7mm so far. No 11mm monsters yet. I'm actually kinda disappointed.

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Gosh, that's a shame.

Let's all wish neptronix dozens of 15mm goatheads!

Yes, for science!!!

They must all be in California goatheads seem like they are are getting bigger every year. Flatout is a requirement.

neptronix said:

Oh there ya go.
Tannus armor is 15mm thick, maybe 7mm when compressed, any tire will work with it.

What i don't like about the Tannus is that i'm told it has negative effects on handling and a 6 month lifespan... the manufacturer even recommends you depressurize the tire after riding. That makes it high maintenance.

I also don't like added rolling resistance. ( Tannus creates more than a sealant would )
Tannus HQ is about 30 miles from my house, go figure they invented the most hardcore anti-goathead solution.

With this thread i'm trying to see if we can get a single layer goathead defense - the tire.
I'll go to multimodal defense if i need to. The next step for me would be flatout ( off road formula, specifically ).
Why flatout vs any other sealant? it lasts a hell of a lot longer ( years ) and is said to seal larger holes.

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FWIW I live in the land of pointy things running fat tires (appropriator for our desert use)

I've run both stans and flatout and had much better luck with the stans. With stans I run 2-4x what they recommend and replace about once a year. Tried the flatout and while never got a flat on the road I have gone to go ride and the tire was flat from a not very significant sliver of metal. The flatout is super thick (viscosity), makes molasses look thin, and I don't think it coats as well as the stans which is about as opposite as far as being thin. The flatout is a lot less expensive though but in my experience I still think it needs replacing periodically.

With stans I've picked up numerous goat heads (see pic) and other very large thorns (some as large as 1/8" dia) in many thousands of miles no flats. Couple of points though... like scabs, don't pick the thorns or goat heads... let them break off while riding. And when using the sealants in tubes *any* time the air is let out from the tire clean out all the pointy things (I just use wire clippers) from the inside of the tire - there are times when doing the annual replacement that there are dozens which attests to the effectiveness. It seems as though if you try to inflate a tube with even one pointy thing still in there it just keeps poking/tearing or whatever and it will likely leak.

For my annual maintenance I remove the tube, rinse it out and refill. Then I'll turn the tire inside-out and clip all the pointy things. Easy peasy.

YMMV

Thanks for sharing your experience!

How many mm thick is your tire? is it a regular thickness, or a puncture proof of sorts?
I would guess this tire is kind of flat prone due to the super small coverage of tread area. That's more challenging than my abnormally thick, almost full tread tires i think.

I think any kind of sealant would be more effective in a thick tire vs a regular one simply due to the fact that there's more depth for any kind of sealant to grab onto. Stans is kind of like a liquid rubber

The thickest goathead i've pulled of my tires this year had a 5mm long spine.. instead of the 11mm monsters of yesteryear. I'd love to see one of your giga goatheads, 1/8" diameter of the poker sounds insane.

I'm told that flatout can last up to 10 years and local MTBers say stans lasts 6-9 months, so higher maintenance. At what point does stans become a solid mass in your tire, would you reckon??

The tire isn't anything special, 120tpi Maxxis Minion FBR - no longer available in this size, too bad too, it's been one of the best tries from a longevity, handling and traction (hard or soft) standpoint.. Don't know the exact thickness but I've had thorns that are close to an inch long and 1/10" - 1/8" in there... goat heads are everywhere out here and it would be an unusual ride where I didn't pick one up.

Doing my annual maintenance, the stans doesn't become a solid mass, it just turns weird, no longer white and not as sticky, more watery, so I pour it out, rinse out the tube with water and put in the new stans.

I tried flat-out in two bikes with stans in one tire and flat-out in the other.

The flat-out failure was very premature - only a hundred miles or so although admittedly the bike wasn't being ridden much since this was a particularly brutal summer so it had been a few months. Went to the bike and the tire was flat. Pulled the tube/tire and inflated the tube and put it in a sink of water to find the leak and patched it. I always put the stem at a point on the tire where it lines up with the rotation direction arrow so I can put the tube with the patch and find the offending object that caused the leak and all it was was a tiny sliver of metal, smaller than most thorns and only penetrated maybe 1/8". Cut it off, turned the tire inside out, nad ran my hand along the inner surface and found no other pointy things. Since I still had half a bottle of flat-out I put the entire half bottle in and we'll see but I'm not terribly optimistic. The stans tire was fine and I didn't touch it. The flat-out seems considerably heavier volume to volume compared to stans.

I've got about 10kmi on stans and never had an in-field flat although I did once have a similar experience with coming to the bike and a tire being flat however that stans was pushing a year in the tube (maybe more, I get lazy sometimes) and it had dozens of pointy thing in it...

Even if the flat-out makes it for a year I doubt I'll return to it and just keep with stans. The annual maintenance is super easy so I don't really care and I'm not so sure I believe the flat-out is good for more than that either and would replace anyway since flats suck. It is less expensive, but not that much...

Too bad Kenda doesn't offer a tubeless 26" tire:

(Check under "Tire Style" in the link below to see what tires Kenda offers in tubeless)


For something like a goat head thorn the interaction between tire and tube can't be a beneficial one.....even if the tube has sealant in it.

Yes I know the Drumlin Cargo and the other tires you chose offer the highest level of puncture protection Kenda has to offer.....but once that goat head pierces that protection layer the inner tube is going to be a detriment to continued inflation pressure.

See to me that is the irony of a tubed tire in a case like yours. It's because you use a tube that your tires have to be extra thick.....and then on top of that the presence of the inner tube further increases rolling resistance (re: inner tube rubs against inside of tire when the wheel is turning creating friction which increases rolling resistance.)

That's why i talked about adding a sealant in the beginning, but so far, no punctures on either of these tires this year.

azebikeguy might have convinced me to switch to stans and just deal with the maintenance aspect. I want to try flatout first though ( if needed )

AZeBikeGuy said:

The tire isn't anything special, 120tpi Maxxis Minion FBR - no longer available in this size, too bad too, it's been one of the best tries from a longevity, handling and traction (hard or soft) standpoint.. Don't know the exact thickness but I've had thorns that are close to an inch long and 1/10" - 1/8" in there... goat heads are everywhere out here and it would be an unusual ride where I didn't pick one up.

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Let me know when you have a depth figure. If they don't weigh 2-3 pounds i'm doubting they are deep.

I've bought puncture proof tires from a lot of brands over the years, never measured more than 7mm of thickness on anything, so i think these tires with 8-9mm of depth are special because most 'puncture proof' bike tires have substantially less material and are close to useless in my area.

The drumlin cargo is also the hardest bike tire i've encountered and i think the hardness of the tire is a plus for goathead resistance but i can't prove it yet.

neptronix said:

That's why i talked about adding a sealant in the beginning, but so far, no punctures on either of these tires this year.

azebikeguy might have convinced me to switch to stans and just deal with the maintenance aspect. I want to try flatout first though ( if needed )



Let me know when you have a depth figure. If they don't weigh 2-3 pounds i'm doubting they are deep.

I've bought puncture proof tires from a lot of brands over the years, never measured more than 7mm of thickness on anything, so i think these tires with 8-9mm of depth are special because most 'puncture proof' bike tires have substantially less material and are close to useless in my area.

The drumlin cargo is also the hardest bike tire i've encountered and i think the hardness of the tire is a plus for goathead resistance but i can't prove it yet.

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I'd be interested in others that have tried both. My one anecdotal experience with the flat-out isn't terribly relevant but it soured me anyway since I've got so much time and mileage on the stans. It's also handy that they carry stans at pretty much every LBS out here (that tells you something?). They are night and day different though. Stans super thin and smooth and flat-out incredibly thick and chunky.

I doubt the tires are all that thick, tubes definitely standard. When I bought them supposedly they had "EXO Protection" available (cut- and abrasion-resistant material added to the sidewalls) but I don't think I got that and not like it would make a ton of difference since 95+% of the pointy stuff is in the treads. Regardless, there is no doubt in my mind that plenty of stuff pokes well into the tubes...

I just inflated my tires with Spanjaard Tyre Fix and that was that for flats.

This stuff:

I've also heard good things about Green Slime.
Probably this stuff:

green slime is ok as a short-term get you home solution, putting it in only if you get a flat, it'll plug a lot of pinhole flats pretty quick as you air up the tire and spin it around.

the ones it doens't stop it's going to fill your tire with green stuff and coart the tube so youc annot patch it until you clean all the slime off everything really well with soap and water, so don't expect to be able to do roadside repairs if you use it. if it doesn't work you're chanigng that tube out or walking home or riding on your flat.

If you ride with it in your tires it's going to ball up in there and clog up the valve too. it's probably worse here where everything cooks in the sun, but... back when i rode plain bicycles, i used it for a really long time and just lived with the fact that i'd have to take the innertube out every so often, fill it with hot hot water to soak the lumps of slime and squish them around with my hands until they dissolved enough to force them out thru the valve stem (after removing the valve to get the water in there). usually this was several hours of screwing around, so i would put it off and then end up getting a flat that the stuff couldn't plug because it wasn't liquid anymore. and if you already have chunks in there, they seem to catalyze the process to happen faster than normal; the bigger the chunks and the older they are the less likely that adding new slime will work for more than a few weeks. and the longer it's in there as a chunk the less likely you'll be able to dissolve it to get it back out.


they have stuff with chunks of rubber in it too, but that doesn't work on normal bicycle tubes/tires, as it is meant to get into the tire rubber and fill the bigger holes. the thinner bicycle stuff flexes so much that even if a plug occurs it will not stay in there long enough to be useful.


i find it mroe useful to try to prevent the flats in the first place by using thicker rubber to start with to keep the pointy crap from touching my air.

Yeah i've had bad experiences with slime; that's why we're here, talking about tires with 8-9mm thickness... plus sealant!

Well... do try the Foam.
I fixed a car flat with foam temporally.
~5 years later it was still running the temporary fix.

In the BMX days we'd club together and buy one for a couple of bikes.

Thx for the heads up on the slime. I never did try it. Just the foam.

Used slime many years ago and at least in my experience in the land of pointy things far more hit and miss than the tubeless sealants.... even in thick moto tires/tubes... Don't recommend it and neither do the LBS's here...