• Howdy! we're looking for donations to finish custom knowledgebase software for this forum. Please see our Funding drive thread

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

neptronix

Administrator
Staff member
Joined
Jun 15, 2010
Messages
18,330
Location
Utah, USA
Howdy.
If you've known me for a while, you know that i'm off my bike due to increasing amounts of goathead thorns in my area. It's caused me to use motorcycle tires which suck because they're nearly impossible to get off a bike rim.

The offending object in question:

1710305173468.png

The problem is, the pointy part of goatheads in my area get up to 11mm in length. A marathon plus is not adequate because it has a total of ~7mm rubber. About 1 out of every 50 goatheads punctures the tire. In a single ride, i can pick up dozens, so my odds of a goathead flat are basically every other ride.

I went looking this year to see if there were any improved bike tires, sealants, etc, and came up on the kenda k-plus models, the Kwick Drumlin and Kwick Journey. The Drumlin was out of stock, so i settled for the Journey model:

1710303832060.png

Weight for a 26 x 1.95" tire is listed as 1335g, or 2.9 pounds. Heaviest bike tire i've seen on the internet! I figured there'd probably a lot of rubber on this thing, which is a good sign for puncture resistance.

I decided to order a k-shield ( 800g much lighter ) and k-shield plus version for comparison in the name of science.

Both tires had a harder than regular compound, closer to a motorcycle tire. They also have a marking for moped on them. We're off to a good start.

pop_kenda-moped.jpg

To compare the tires' total thickness, i have a special 11mm thumbtack, and use a section of a Mitas MC2 ( average moped tire ) as a comparison point.

In the Mitas poke test, it's quite difficult to get the poker all the way in with my thumb. We have a very stiff compound, but only 8mm of rubber.

pop_mitas-mc2.jpg

Note: in the proceeding pictures, i am holding the pin in with a thumb to max out the amount of puncture. In the above picture, the pin happened to stay in at max puncture, probably thanks to the hardness of the tire.


Okay, let's poke the k-shield tire from the top. The tire itself is slightly easier to poke than the moped tire, but much harder than a regular bike tire. This is good, except we don't have a lot of rubber here.. we get a puncture from an average length goathead for sure :/

pop_kshield1.jpg

The side poke is equally unimpressive. We have an about equal amount of protrusion.

pop_kshield2.jpg

OK, in reality the harder rubber may make up for the less than stellar depth. But this just seems like a totally average puncture proof tire overall, basically it lives in the shadow of the Schwalbe Marathon Plus for having around 1-2mm more protrusion than in my last test.


What about the k-shield plus?

Tire compound was also hard while poking but the overall tire was much harder while handling it; it really felt like a moto tire. Obviously there is a damn lot of material in this tire.

Holy smokes, we only have 1-1.5mm protruding! This is about as thick as a mid size motorcycle tire i've measured in the past!

pop_kplus1.jpg

Same deal with the side poke, nice protection while turning too!

pop_kplus2.jpg

I have to say.. with a tire liner or sealant or thick tube, this tire could easily be made immune to these demon goatheads. I'm extremely impressed with the sheer amount of rubber here, it's more than a moped tire and as much as a light-medium motorcycle tire.

The only downside is that both tires are quite warped in all dimensions upon recieving, probably from sitting bunched up in a hot warehouse..?
I imagine a couple summer rides in salt lake city would probably even them out.. but.. i never received such warped/bent tires before.

Ordering another k-shield plus to complement the other so i can ride this in real world conditions without any additional protection and let you know exactly how much extra i need. Plan to experiment with Flatout sealant and thick tubes first..

Will report back on that, but i just had to share this hot tip :es:
 
I'll be interested to see how the sidewalls hold up, given what i've seen happen to every Kenda tire I've ever looked at or had.
 
Have you ever tried any of the Cushcore-type foam inserts that allow you to run flat? Some of the downhillers here run those with sealant. What a nightmare. In socal the goatheads seem prevalent mostly in the fall (October), but lie quietly the rest of the year.
 
Cush core won't do anything to prevent flats, i think your rotating weight budget is better spent on something that fixes the original problem, not the symptom of it.
 
Have you ever tried any of the Cushcore-type foam inserts that allow you to run flat? Some of the downhillers here run those with sealant. What a nightmare. In socal the goatheads seem prevalent mostly in the fall (October), but lie quietly the rest of the year.
Note that if you use those, Tannus Armour, mousse, or whatever foam nonsense inside the pressurized space, the foam will compress to a fraction of its original thickness unless you're also using very low squishy tire pressure. There's a place for that, but on the street isn't it.

My experiment with Tannus Armour showed that it didn't prevent the kinds of punctures I face most often (construction fasteners and metal debris), but it did adversely affect handling and rolling resistance, and it made the tire treads crooked. On top of this, whenever I pulled it out to deal with a problem, I found it to be much thinner than when it went in (like less than a third as thick).

Tannus says the liners will fluff back up if you let the pressure out of the tires for a while, but that isn't a practical solution for me (nor effective, if pressurizing the tires again squishes the liners flat immediately).
 
Yeah, that.
Everything i've read indicates Tannus is an option of last resort.
Local bike shop says the inserts last 500-1000 miles on a non-powered bike.

It would probably work for my goatheads, but i really want to get my extra protectiona better way.

I think that the extra depth of a tire like this would help make a sealant work better, because there's more distance which a plug can form, even if it's just a few millimeters.

The second k-shield plus tire is on it's way.
 
Those are quite heavy.. I am running a 26" Schwalbe Big Ben Plus at 2.15 wide, it lists as under 1 kg. Tough enough for me so far, no flats.
 
I wish they were heavier!

If you live on the east coast, you don't have to contend with anything like this. You can disregard this entire thread. This is mostly a desert/high desert problem.

1710381199929.png

( BTW, these ones in the picture are smaller than the ones in Utah )
 
Thanks for this Nep. I've been having problems on and off for years with my BikeE's. My main problem is pinch flats though, and I'm constantly looking for the best balance of tire pressure and flat prevention to compensate.
For the last few years I've been running Tannus armor with mixed success. Yes, what Chalo say's is true about them compressing, but the big/main advantage I find with them is I can still ride home at slow speed following a puncture without trashing my rim (too much). I have managed to get a few pinch flats even with the tannus installed, but that was partially because I was still figuring out what pressure I needed to run.
I find with smaller diameter tires I need to crank up the pressure to around 40PSI while using Tannus in order to keep things in place. With larger tires (over 2.1") the pressure can be dropped to more comfortable levels while retaining most of the benefits.

Glad I don't have to deal with those goat heads, they look nasty. I just have to deal with my tendencies to smash into rocks and gutters at way to high speed. :p

Cheers
 
Pretty sure my tires are Kenda K Shields and 2 flats in a couple of weeks. Looking at Schwalbe pickup

So.. not k-shield plus models? ( it'll say KS+ on them if they are )

If so, schwalbe pickup should be a little better but the k-shield plus would be better than anything Schwalbe has to sell.
 
Thanks for this Nep. I've been having problems on and off for years with my BikeE's. My main problem is pinch flats though, and I'm constantly looking for the best balance of tire pressure and flat prevention to compensate.

Interesting, i never get pinch flats on a recumbent, but i also like to run 50 PSI. On the bikeE, you may want to inflate the tire more than usual to counter compensate for the fact that 80% of your weight sits on that back wheel.

TBH, my recumbents never exceeded 60kmh, so maybe some degree of your issue is related to speed.

Glad I don't have to deal with those goat heads, they look nasty. I just have to deal with my tendencies to smash into rocks and gutters at way to high speed. :p

..last statement confirmed 😅

Maybe a cargo bike tire, which tends to be harder than usual, high PSI, and as fat as you can go is the answer?
 
Maybe a cargo bike tire, which tends to be harder than usual, high PSI, and as fat as you can go is the answer?
Yes! I tried going smaller (1.75") as I had load of issues with some fatter tires....that was before I finally realised what the difference between folding and wire bead tires really is.
Now I have these two on order:

I'm hoping at least one of them works better. Ideally there would be a 20" tire that is around 2.5-3" with thick sidewalls and built in puncture protection and decent nobs. I really need them nobs as the smoother tires just slide all over for me currently.

Cheers
 
So.. not k-shield plus models? ( it'll say KS+ on them if they are )

If so, schwalbe pickup should be a little better but the k-shield plus would be better than anything Schwalbe has to sell.
My mistake. They’re CST’s. The bike model comes with Kendas now.don’t think K Shield plus is an option for me with 24”, Schwalbe pickup looks like decent option for cargo bike
 
Cush core won't do anything to prevent flats, i think your rotating weight budget is better spent on something that fixes the original problem, not the symptom of it.
Good point! Also, what Chalo said ; these guys are off road only, downhill chargers.
 
OK, FYI..
Kenda's store is incredibly flaky.

Two support tickets not responded to over the course of a week, one which prevents me from making additional orders.
I found a way to make my second order for the 26 x 1.95" KS+.
I also received a duplicate of the original order today.
Time to file another support ticket to see if they'll pay for me to return it - don't need it.. don't feel confident that i'll hear back.

Wouldn't recommend buying from their store.
 
Nope, didn't get charged twice. Just checked now.
No answers to many of my messages. They either literally don't have customer support or their outgoing email is broken.
No phone number to tell them about that either.

I did get the 26" x 1.95" tire in a few days ago, an ounce shy of 3lbs, just beautiful, can't wait to ride it through a place locals call 'goathead gulch'
 
I felt so weird ordering Kenda tires, I have heard the back and forth with puncture issues etc. not a lot ot add to tat.. but hte boy hit me up and he wants next years "commuter ebike" he is starting Jr High, he wants it to be "More stylish, so I talked to Uncle Tony, he knows more about dressing nice and style than you (for the record, I only wear cargo shorts because they are timeless and awesome). Consequently... he wants blue tires on his bie ::hangs head in shame:: and those from what I ahve seen are only Kenda.

But, boy wants blue rubber, boys gonna get blue r=ubbah...
 
Consequently... he wants blue tires on his bie ::hangs head in shame:: and those from what I ahve seen are only Kenda.
I've never tried any pre-colored tires besides black, so I don't know if any of these are what you're after...but there are ones that don't appear to have Kenda molded into the rubber, so they are probably made by other makers. Whether those are any better than Kenda, I couldn't say....


The only serious problem I have had with Kendas is that the sidewalls disintegrate, rubber flaking off the carcass threads, weakening the tire. I still wouldn't buy the brand on purpose, but I'd rather have Kenda than most of the really cheap or "noname" "brands", some of which don't even have a real weave inside the rubber to keep it together. :/
 
Back
Top