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

[Cowardlyduck]

That's a fair point....no goatheads in my area thankfully!
That being said, another factor for me is that I use Tannus Armor as well. I did have lots of puncture issues on various ebikes over the years. That was mostly solved by using old tubes as tyre liners, then even more solved by using Tannus Armor more recently.
I also recently started adding some Stans no flat in my tubes which has helped a few times. Like you, changing a flat is a non-option for me so I do everything I reasonably can to avoid.
A more frequent source of flats for me is ripped valve stems (from too low pressure) or pinch flats from smashing into sharp edged rocks (again typically with too low pressure) or too much speed for the terrain.

Have you tried running something like tannus armor in combination with an old tube as a tyre insert? Just an idea and something I would try if I had those goatheads.

Cheers

 

[neptronix]

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.

 

[Cowardlyduck]

I would recommend at least trying Tannus armor. I 'solved' the high maintenance issues simply by getting 2. Just rotate them when changing tyres.
As for handling, it's not quite as simple as it only being worse. Running Tannus means you can run lower pressures....that in turn can improve some aspects of handling.
In my case it's a middle of the road solution. I typically run 35-40PSI with Tannus and don't get punctures. Without it I ran about the same pressures, but did get occasional punctures.

Cheers

 

[neptronix]

I'll try it but it's last on my list.

I like to run high PSI ( 50-65 ) for efficiency and use suspension to provide the compliance that the tires don't provide at that point.
Only time i had a pinch flat was on a roadbike with 23mm wide tires. just not a problem i encounter on an ebike.

I believe a harder compound is key. it might be the reason why i've never seen goathead remnants in motorcycle or a very worn car tire ( less than 11mm rubber remaining ).

 

[slaphappygamer]

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 have these inserts. I’ve had the same set for over 2 years. I don’t depressurize the tube either. I have Schwalbe motoX tires. I’ve only got a flat once and n the last 2 years. It was a metal clip that penetrated 2 inches into my rear tire. Im fairly certain that this would’ve popped most tires.



I just do regular tire maintenance. Check air pressure, look for things sticking in the tire.

The Tannis Armor set I got also came with smaller tubes. I keep those inflated to 25PSI. Doesn’t need much air since the overall volume is much less. The ride is softer than without Tannis.

 

[neptronix]

Slaphappy, i'm surprised you had a set last 2 years. MTB oriented local bike shops say 6 months.

What's your riding/ride like, in particular:
- are you pretty light?
- low miles? lots of miles?
- street, offroad, what?
- how fast?
- what size tires & what PSI?

Cowardlyduck, you got me thinking. I have a severe chatter problem on the front wheel of my Maxarya recumbent. I know low pressure or massive amounts of rubber solve the problem; but both come with compromises. Maybe a Tannus insert would have less added rolling resistance vs the massive rubber option? ( example: moped tire )

I hear Tannus' armor inserts deaden road imperfections to an extreme. The problem with my recumbent is that there's practically no weight on the front wheel. But maybe ~20% of the dampening capability of the Tannus is enough to make a dent.


According to bicyclerollingresistance.com, tannus armor produces a lot of rolling resistance at higher PSI than the company recommends for the longevity of the insert.


Ref: Puncture Resistant Tire Liners Test | Bicycle Rolling Resistance

Two sources say Sealants have very low rolling resistance addition. In this case on a skinny tire, we only add 5.5 watts at 45kph/28mph.



Again on a road tire:
Top 3 Fastest Tubeless Vs Latex (and Butyl) | Bicycle Rolling Resistance:


This is why Tannus is my last choice except for the exception case: my Recumbent's front wheel.

 

[neptronix]

Looks like super expensive tubes could help cut down some of the rolling resistance:



Small effect - a few watts per wheel - but should counteract ~50% of the negative rolling resistance of sealant; i'm surprised at the effectiveness of this.

 

[Cowardlyduck]

Well in my case I use Tannus in the rear only as my front is 16" and they don't make an insert that small + I've hardly ever had puncture issues up front, and I carry (and can easily change) a spare 16" tube.
Interestingly, my rear rim is not very 'round' ever since I had a bad pinch flat about 18 months ago and tried to ride it home on the rim. I very nearly completely destroyed the rim, having to grind it back to a non-sharp/usable state and have an annoying flat spot I can't fully remove.
Point being, it wants to buck me off sometimes due to the amount of chatter at speed. The Tannus might be deadening that I'm not too sure. I did run the rim without Tannus for a brief period after the rim was trashed and do recall the chatter being worse, however I've tried truing the rim more and swapped tyres in addition to reinstalling Tannus since then so can't be sure the reduction in chatter is from the Tannus.
It's still bad enough mind you that I'm currently debating if I buy a new 20" rim, or switch to a small MC rim in the rear. 'That' would open up all manner of light moped tyres I could then switch to also.

Is that something you've considered Nep? The MC rim/tyre option that is.

Cheers

 

[neptronix]

No need for a MC rim to use moped tires. you just need decent width ( 28-36mm internal width ). 16" in moped/motorcycle world is 20" in bike world.

I've ran dozens of motorcycle tires over the years. You'll take a big hit in rolling resistance, but the ride will be very smooth. I recommend checking out the tire selection at treatland.tv - they specialize in mopeds and have a good selection of tires.

 

[slaphappygamer]

What's your riding/ride like, in particular:
- are you pretty light?
- low miles? lots of miles?
- street, offroad, what?
- how fast?
- what size tires & what PSI?

I weight 160lbs. With cargo, probably 180-190lbs.

Hard to say how many miles exactly. I’ve changed from the stock system, to the KT system, and finally the Grin system. I’d guess, in the last 2 years, 2500 to 3000ish miles. I really only commute to and from work. I won’t ride if it’s raining.

All my riding is street a very narrow 3 bike lane and there are potholes. I take one paved path that leads to a wooden bridge and I rarely go over 25mph. The bridge is probably 80’ and I go about 10-15 mph there. Probably average 18-20mph along my total 3.8 mile trip from home to work. Close to 8 miles a day.

I use these tubes with the stock 27.5 x 2.4 Schwable Super MotoX tires. I maintain 25psi. That was the recommended pressure. I’m trying to find where it said that. With the stock tubes, without the armor, I kept them at 50psi. The ride is dampened, but the potholes are less jarring. I avoid most of them, but I hit a few now and again.

I’ve come the conclusion that whatever the manufacturer says about product life and maintenance (such as don't hit me oil changes) can be greatly extended upon use cases. I drive my car a couple times a month and my oil is still good after almost a year. I believe I’m pretty easy on my things. I want them to last. I’m sure that MTB LBS says 6 months to “keep your warranty up to date” or simply to sell tires more frequently. The LBS may not know specific of your particular MTB usage so there is may be a blanket statement to cover their ass. I’m pretty sure MTB riders are harder on their bikes and ride more frequently than I do. I could be wrong. Each LBS is different. Im on the outside looking in and this is just my opinion, I don’t work at a shop.

 

[neptronix]

Very good information, thanks!

I've ordered a tannus for my recumbent front wheel.

I'm surprised the in-wheel pool noodle helps dampen potholes, and also, survives those potholes without deforming after such a long period of time.

I wonder if inside your wheel, it's flattened over the years, leaving you with ~5mm of foam - which is still 3x the protection you'd get from the world's best, thickest tire strip. Have you ever inspected it?

 

[Cowardlyduck]

Have you ever inspected it?

Yes. It's squashed pretty flat/hard when ever I go to change a tyre. I don't mind as I usually just swap in the spare that has re-expanded. I don't know how long it takes to squash....and don't care either....it still does it's job.

Cheers

 

[offGridDownUnder]

I've ran dozens of motorcycle tires over the years. You'll take a big hit in rolling resistance, but the ride will be very smooth.

Is there a thread or a site you can point me at that discusses using moped/motorcycle tires on a bicycle (trike in my case). Information about what rim sizes correspond, other details to help make choices?

Thanks.

 

[offGridDownUnder]

the spare that has re-expanded.

This is key. You find it re-expands consistently?

 

[99t4]

Rolling resistance. We have a tendency to get hung up on rolling resistance. It's appealing to use components that test best and provide the best "numbers" but are those tests actually measuring what we encounter in our actual cycling environments?

If the rolling resistance is measured on a dyno with an ultrasmooth drum, does that really correlate to riding on a rougher road? Apparently narrow hi pressure tires inflated to max recommended pressure win the rolling resistance test but what happens IRL when that tire is on the rear, ridden on a rougher road which causes the tire to bounce off each nonsmooth imperfection, becoming momentarily airborne? Wasted energy due to wheelspin each time the tire bounces up in the air. It is not propelling the bike forward So the (tested best) LRR tire wins the (lab) test but loses in overall efficiency when run on the road in real life conditions. Didn't Rene Herse Cycles test this numerous times?

Then, there are other aspects that should have higher priority. In Nep's case, it is goathead thorn resistance. Harder compounds might be the answer. For me, better traction in wet and cold conditions is more important. Harder compounds would have me sliding all over the place. I've taken too many diggers riding over wet manhole covers so gladly prefer softer stickier compounds that may happen to give up a few rolling resistance percentage points.

Just as we on our motorized ebikes can slack off a bit in the usual biker quest for ultralight everything, we should be able to relax a bit in the quest for ultimate (as tested?) (what test conditions?) LRR tires, and tubes, in order to satisfy some of the other important priorities.

 

[neptronix]

Is there a thread or a site you can point me at that discusses using moped/motorcycle tires on a bicycle (trike in my case). Information about what rim sizes correspond, other details to help make choices?

Thanks.

I've posted a number of threads on that topic:
Search results for query: motorcycle by neptronix

 

[slaphappygamer]

Have you ever inspected it?

Well, after that clip penetrated the tube, through the armor, the foam was still doing its job. I recently pulled this out.





This did not pierce the tube. I noted the tire pressure, then checked the next morning and no air leak. I was just randomly checking for anything stuck that could be pushed in further. This was angled away from the middle of the tire. It was all the way in. This was in August. My last flat was that metal clip (pictured with the lighter). That was in March.

I haven’t measured the thickness of the foam, but it’s still doing its job.

 

[Cowardlyduck]

This is key. You find it re-expands consistently?

Yeah, seems to be fairly consistent and they seem pretty robust....funny story about that...

When I had the episode described above where I ended up riding on the rim, it was not a good time. I had problems with my phone so couldn't call for help, texts were barely getting through and I didn't know if I was going to have to make my own way 10-15km back home. So I started disassembling the rear to swap in a special tube I carry called Gaadi tube that is non-cylindrical and can be installed without removing the rear wheel.
Anyway, after stuffing around for over 45min, trying and failing to ride on semi-repaired setups multiple times and eventually got picked up. In the kerfuffle of the whole episode I somehow ended up leaving the Tannus Armor by the side of the road and completely forgot about it.

I swapped to another bike to ride until I could fix up the busted rim of the one with Tannus Armor. That ended up taking over a month and by the time I did fix it, I completely forgot about using Tannus Armor as when I went to swap in a new tube/rim it wasn't there so didn't think about it.
Anyway, about 4-5 months later I was riding further along from where I had all the previous issues (an area I don't normally ride) and low and behold, I find a 20" pre-cut Tannus Armor sitting by the side of the road.
At first I just rode past it, but wasn't until a few days later I realised.....hey that's mine!
So I swung back past and picked it up of the ground a few days later. This was in a populated area, next to a foot path/busy road so it's amazing it sat there so long.

I took it home, cleaned it up, and used it the next time I changed a tyre again. Been using it ever since....works fine still.

So yeah....they are pretty robust.

Cheers

 

[slaphappygamer]

Yes. It's squashed pretty flat/hard when ever I go to change a tyre. I don't mind as I usually just swap in the spare that has re-expanded. I don't know how long it takes to squash....and don't care either....it still does it's job.

Cheers

Are you using the same size tube as without the armor? I think using a smaller tube helps the armors longevity.

 

[Cowardlyduck]

Are you using the same size tube as without the armor? I think using a smaller tube helps the armors longevity.

No. I want all the protection and choose to live with the downsides so I still run a full sized, extra thick tube, and then also add sealant.

On the road, I don't notice the handling negatives that much cause I'm not turning heaps. Off road, the confidence of smashing into rocks/roots and other obstacles, knowing I won't get a puncture far outweighs the minimal impact on handling performance.

Cheers

 

[neptronix]

Rolling resistance. We have a tendency to get hung up on rolling resistance. It's appealing to use components that test best and provide the best "numbers" but are those tests actually measuring what we encounter in our actual cycling environments?

No, but i've done the test IRL.
On my recumbent with a 1kw mid drive, it's the difference between 32 and 35mph.
On a pedal bike, the amount of additional effort needed is massive; makes the bike unrideable. That's with a rear MC tire, and a front bike tire.

I was a big proponent and user of motorcycle tires when i was in the 4-8kw club. Now i'm in the 1-2.5kw club, i'm a lot less of a fan.

If the rolling resistance is measured on a dyno with an ultrasmooth drum, does that really correlate to riding on a rougher road? Apparently narrow hi pressure tires inflated to max recommended pressure win the rolling resistance test but what happens IRL when that tire is on the rear, ridden on a rougher road which causes the tire to bounce off each nonsmooth imperfection, becoming momentarily airborne? Wasted energy due to wheelspin each time the tire bounces up in the air. It is not propelling the bike forward So the (tested best) LRR tire wins the (lab) test but loses in overall efficiency when run on the road in real life conditions. Didn't Rene Herse Cycles test this numerous times?

I've heard of this before & also observed it on roadbikes. That's why i like to top out at 60 PSI. I find myself slowing down to lower NVH on our crappy pavement at PSI higher than that.

For me, better traction in wet and cold conditions is more important. Harder compounds would have me sliding all over the place. I've taken too many diggers riding over wet manhole covers so gladly prefer softer stickier compounds that may happen to give up a few rolling resistance percentage points.

I can see that. I had a couple year stint in the Portland, Ore. area and now live in the high desert where the heat does a great job of softening up rubber.

I dunno though, this tire has a lot of meat on the sides, and nice grippers at the edges. They look like they're designed to roll fast but also help you recover from slippage. We have a lot of dust/dirt here and i don't feel uncertain traveling over it. But yeah, wet world is different. I'll have to try them in the snow.

 

[neptronix]

ps great discussion about the tannus. I learned more here than i did in 45 minutes of scanning reddit and the wider web.

 

[offGridDownUnder]

Wasted energy due to wheelspin each time the tire bounces up in the air

Not disagreeing with what you wrote, but pointing out another aspect.

Higher tire pressure is heading towards a hypothetically rigid tire - that is, one with no give. Lower pressure heads towards a tire that does all the giving (absorbing movement) in the body of the tire.

A perfectly rigid tire will lift the entire weight of the bicycle and rider on each bump - including all the tiny bumps in a 'smooth' asphalt pavement. Energy does not 'disappear' - this is actual work that comes from somewhere, it is accounted for, and on a bicycle it comes from the rider pedaling. It will dissipate as heat, but it comes from the rider.

The energy to flex a tire over a small contact patch is much lower than the energy to lift a rider the same deflection distance and it is real and it adds up even if we don't think about it.

This is why Schwalbe can measure lower rolling resistance in their 'balloon' tires as compared to high pressure tires. The 'balloon' aspect means the tire has enough volume for the flex to encompass all of the movement imposed by the ground without transmitting any of it to the rim and the rest of the bicycle. This also happens to mean that there won't be rim damage as the impacts never reach the rim.

 

[amberwolf]

Yes. It's squashed pretty flat/hard when ever I go to change a tyre. I don't mind as I usually just swap in the spare that has re-expanded. I don't know how long it takes to squash....and don't care either....it still does it's job.

Someone needs to stick a wireless camera inside the tire to see how long it takes and how far it compresses initially. You can get very small ESP32 wifi cams for cheap, add a tiny battery, and IIRC there's code out there already to make a wifi image taker / server that can be accessed from a phone.

Would be funny to see that it compresses fully upon initial airing up, which would then mean that there isn't a "lifespan" for them regarding that part.

 

[amberwolf]

It's still bad enough mind you that I'm currently debating if I buy a new 20" rim, or switch to a small MC rim in the rear. 'That' would open up all manner of light moped tyres I could then switch to also.

No need for a MC rim to use moped tires. you just need decent width ( 28-36mm internal width ). 16" in moped/motorcycle world is 20" in bike world.

I've ran dozens of motorcycle tires over the years. You'll take a big hit in rolling resistance, but the ride will be very smooth. I recommend checking out the tire selection at treatland.tv - they specialize in mopeds and have a good selection of tires.

As Neptronix says, if you go with a 20" BC rim you can use 16" MC tires. I've been using the Shinko SR714 2.25" on SB Cruiser for years successfully, with none of the usual BC tire failures or flats. The flats I have had were either straight up tube failures or punctures that would ahve taken out any of the protections I've tried on BC tires.

Note there are at least two common sizes of 20" rim, so make sure yours are the right one (406? don't recall ATM but I'm sure it's in one of my posts somewhere). Whatever BMX is is probably the right one.

I use MC tubes, too, CST if I can get them (most consistent brand of those I've tried that actually had a manufacturer on them). I usually order the BikeMaster Motorcycle Tubes 2.25/2.50-16 TR6 valve type. (those fail far far less than rubber-covered valve stems)


Disadvantages are that while much thicker for puncture resistance, they are also much heavier. They also add more drag, so the motor is pretty well necessary. (It's already necessary for me, as I am not able to ride even a regular bicycle (or trike these days, balance issues) very far or fast, so me being unable to ride this trike on these tires more than down the neighborhood street doesn't say as much as you'd think about how much drag is added...but it's more than enough to notice. I'd guess a better rider with correct gearing could ride the SB Cruiser unpowered at <15mph (where aero drag really becomes an issue) easily enough even with these tires.

Like various other tires I've had, they are also not a *perfect* fit for the rims, and if installing new ones I let them just sit wherever they are when first inflating, they will be out of round. So I use zipties to hold their beads centered during initial install and inflation, and after they've sat for a short time (less than a day in the typical heat here) the beads seat in to the rims and I can remove the zipties, and the tire will seat itself correctly in the future if removed and reinstalled.

They are a pretty soft compound, so while this makes them very grippy, it also makes them wear out faster. I require grip so it's a compromise I have to make with all tires.


OTOH, I have been able to ride (slowly) much of the way home (out of 2.5-ish mile commute) on a totally flat tire without destroying the wheel, and the tire was still apparently ok as well. Given the weight on either rear wheel with the SB Cruiser, that's saying something about the tire itself.

On my small trailer that I nowadays use mostly around the yard to carry tree limbs, etc, I use the old worn tires from SBC, and the sidewalls are stiff enough to hold up the trailer and let it roll normally even when the tires are actually flat (usually from a bad valve or tube patch failure, as I use SBC's old tubes in there too, after patching them when possible).