Tire failure modes.

zerodish

10 mW
Joined
Nov 9, 2012
Messages
32
I'm a touring clydesdale I have done 100000 miles with 165 to 190 pounds on the rear wheel. Kevlar tires last 5 times as long as non Kevlar tires if the failure mode is glass cuts. There are 2 main types of these tires. There is the belt or fabric mesh under the thread used by most makers. There is also the chopped fiber used by Performance Geax brands. There is no reason why the 2 technologies can't be combined for a super tough tire. It's been my observation that tires 1.5 inch or 38 mm wide or less fail due to glass cuts. Tires wider than this fail from ripping at the bead. What we need if you want to run wider tires is an extra 2 plies. Attempts have been made to do this. Specialized Armadillo have have an extra 2 plies of flat plies. These tires were used by the Romp Family on their quad on their cross country trip. Details can be found on archive.org The problem with these tires is the rubber does not stick well to the flat plies and the tires delaminate. Continental has a light weight extra 2 plies called gator skins. The problem with these tires is the polyamide thread they use has a greater tendency to tear at the bead. We simply need to tell manufactures we want a tougher tire. They are making spokes for us now.
 
Your thoughts about a tougher tires has been a long held dream around here.
 
These are bicycle tires, and the wasted pedal power and poor ride quality inflicted by extra plies and thick armor belts are unwelcome among most cyclists. I don't think we can expect that overall market condition to change in the near term.

That said, there are some very thick, very puncture resistant tires out there, and not all of them ride as badly as Specialized Armadillo tires. On my 29er e-bike, I'm using Kenda Kwick Drumlin 700x50 tires that are especially hardy. They fall in the category of "tires I wouldn't enjoy on a pedal-only bike". On my pedal bikes, I like Panaracer RiBMo, which is very puncture resistant but also relatively fast and comfy.

Any of the Continental or Schwalbe "Plus" models, Michelin "Protek" models, CST "EPS" models, WTB "Flat Guard" models, or comparable products from other manufacturers will feature effective anti-puncture layers. However much protection, rolling resistance, and tire stiffening you can stand, there is probably a tire out there for you. Some of the most flat-phobic members in this forum have even switched to motorcycle tires.

P.S. - Continental Gatorskins are brilliantly marketed, but lame flat protection. They are only armored compared to completely un-armored tires. And "polyamide" is a generic term for Nylon, which is a trade name belonging to DuPont. Almost all tires are made of it.

I'm curious what spokes "they" are making for us now that you think may be more suitable for us? When I build a wheel to carry 700 pounds regularly and 1000 pounds occasionally, I use 14-15ga double butted spokes because that's what works best.
 
But is all that weight overtop of the hub motor, or are those setups front hub motors with all the weight on the rear?

Chalo said:
When I build a wheel to carry 700 pounds regularly and 1000 pounds occasionally, I use 14-15ga double butted spokes because that's what works best.
 
markz said:
But is all that weight overtop of the hub motor, or are those setups front hub motors with all the weight on the rear?

Chalo said:
When I build a wheel to carry 700 pounds regularly and 1000 pounds occasionally, I use 14-15ga double butted spokes because that's what works best.

They're not hub motors. They're 48 spoke pedicab wheels, and the loads I'm talking about are per wheel, not GVW.

I don't think a typical bicycle hub motor could do that duty, no matter how you build it. The flanges are too narrow and the side covers too weak.
 
The following information is from the Michelin truck tire data book. An 11R22.5 tire has a capacity of 6175 pounds and an 11R24.5 tire has a capacity of 6610 pounds. So a tire's capacity is proportional to it's diameter. Not much but I will take it. A tire's rolling resistance is inversely proportional to it's diameter again not much but I will take. However a larger diameter wheel is less strong unless you use a wider flange a larger diameter flange thicker spokes or stronger rim. Santana rates their 700c wheels at 700 pounds and their 26 inch wheels at 1050 pounds. No idea haw they came up with that.
 
I was shopping for a replacement tire for my cargo bike day before yesterday, and I found a tire that might interest you:

https://bicycle.kendatire.com/en-us/find-a-tire/bicycle/city-trekking/kwick-drumlin-cargo/

The regular two-ply version of the Kenda Kwick Drumlin is already one of the toughest bicycle tires I've ever seen, but now there's a four ply Cargo version with higher load ratings and multiple 20", 24", and 26" sizes available. It looks like 700c and 650b sizes are not made with four ply construction, though.

Like almost all tires right now, availability is poor at the wholesale distributors I deal with. Most sizes can be bought directly from Kenda on their website, though.
 
Chalo said:
.......
The regular two-ply version of the Kenda Kwick Drumlin is already one of the toughest bicycle tires I've ever seen, but now there's a four ply Cargo version with higher load ratings and multiple 20", 24", and 26" sizes available. .......

Hummm now you got me thinking Kenda for my next set of tires.......

k1216.JPG

:D :bolt:
 
There are three different versions that all look the same: K-Shield (2 ply, 3mm aramid/ceramic belt), K-shield Plus (2 ply, 5mm aramid/ceramic belt), and Cargo (4 ply, 3mm belt).

I want the Cargo version for the front hub motor wheel of my cargo bike.
 
this one?
26x2.40 (60-599)
Part No. Compound Protection Tubeless Ready Bead TPI PSI WT (Grams)
214230 SINGLE K-SHIELD/4-PLY CARGO NO WIRE 60 80 1346±67

I wish they made it in a 29", and wider.

I don't see whether it is a "grippy" compound or not; so far all the Kendas I have had were pretty hard and skidded rather than gripping on many road surfaces in cornering and braking. :(
 
amberwolf said:
this one?
.......so far all the Kendas I have had were pretty hard and skidded rather than gripping on many road surfaces in cornering and braking.....

At what speeds? Any added inertial force due to weight?


:D :bolt:
 
e-beach said:
At what speeds? Any added inertial force due to weight?
Typically at 10-15mph or less, occasionally up to 20mph, on anything from a regular pedal bike with just me on it (back when I weighed only about 120-130lbs...feels like a LONG time ago!), to the first version of DayGlo Avenger, a mostly normal bike but with various motors on it (up to a 9C DD in front), with just me on it or up to a few dozen pounds of cargo in the rear cargo pod and deck.

The CST tires I've used in the same situations have all been softer compounds than the Kendas and gripped much better, even when they have very similar shapes and treads. They wear out a lot faster...but they keep me upright and on the road, whcih is worth it. ;)

The hardness of the Kendas and the problems I have had with their sidewalls disintegrating (in cargo situations, so probalby overstraining them...but other brands did not fail like that in the same circumstances!) drove me to stay away from them as a brand, for my usages.
 
Check out the new 2-ply Schwalbe Pick-Up, similar to the Kenda Kwick Drumlin Cargo but I'd obviously trust Schwalbe over Kenda, and it's available in 27.5".
Rated 5/6 for road grip and 6/6 for protection.
 
When I first got into eBikes it was with a folding Silent Force.
Within a month I was tuning it up, bigger motor, controller battery pack.
Along with the extra speed and weight came punctures. (Nearly all road and cycle path riding).
I tried all sorts of make for tyres including some BMX ones and self sealing inner tubes.
But still managed an average 2 to 4 punctures a month and for a few makes of tyres, they just wore out.
So I checked with a local bike shop, if they had any suggestions. They said I should use the Schwalbe Marathon Plus. These were more expensive to what I was buying before, but gave them a go and in a Year never had a puncture.
So I have stuck with this make since. Using Marathon plus on my MTB (26" wheel, 3000w rear hub).
Now using a Big Ben Plus on the front of my Stealth type build.
Never a problem for me with this make. But of course that also depends on the type and quality of roads you ride on.
These tyres do not seem to want to wear out and yet I find the grip very good wet and dry (and snow).
However, I think it is difficult to say if the grip is good or not as this depends on your riding style, bike, weather, road surface etc.
But wear rate and resistance (Flat battery or controller shut down, requiring pedal power) has me pleased and that includes my weight and bike weight being mostly over their recommendations.
They also handle speed well (again, over their recommendations).
 
I took a 21 inch motorcycle tire and covered it with ink. Then placed it on a piece of paper to print the contact patch. The contact patch indicated the tire had 37 PSI in it even though there was no air in it. This tire would ride like a tire with 37 PSI in it if you could keep it on the rim. It is not obvious to me that a stiffer bead has more rolling resistance. The harshness would come only from the fact that it rides like a tire with a higher pressure rating in it. What I am saying is a tire with a Kevlar belt greater than 1.5 inch wide will fail by ripping along the bead before it gets enough glass cuts to fail at the tread. A lower pressure tire is more resistant to glass cuts. The extra bead does not have to run the full width of the tire it could only run near the bead or you could run it the entire width and reduce the thickness of Kevlar.
 
I rode with a flat 19"x3 knobby motorcycle tire and really did not notice a big difference. The tire is a normal dirtbike knobby tire, very stiff, very heavy. I will look into 22" bmx rim with 18" moped tire, but I wouldnt want to go much smaller then 24" bicycle wheel size. Going 21" motorcycle rim and tire will put the overall diameter more then 26" bicycle, closer to 27.5 or 29" bicycle. Might be good for my needs for the front.

Also of note, I had a moped tire that took a lot of abuse. It was on the same 19" motorcycle rim, 1.40" rim width. It would have lasted a very long time if it had not gouged into the rim brake mount and ripped the tire apart. I still got home with zero issues riding on the bare rim with tire off. Normally you'd go ultra slow and be ultra careful riding on a bare bicycle rim, but doing the same on a motorcycle rim I could be far less careful and still rode on the grass mostly.

zerodish said:
I took a 21 inch motorcycle tire and covered it with ink. Then placed it on a piece of paper to print the contact patch. The contact patch indicated the tire had 37 PSI in it even though there was no air in it. This tire would ride like a tire with 37 PSI in it if you could keep it on the rim. It is not obvious to me that a stiffer bead has more rolling resistance. The harshness would come only from the fact that it rides like a tire with a higher pressure rating in it. What I am saying is a tire with a Kevlar belt greater than 1.5 inch wide will fail by ripping along the bead before it gets enough glass cuts to fail at the tread. A lower pressure tire is more resistant to glass cuts. The extra bead does not have to run the full width of the tire it could only run near the bead or you could run it the entire width and reduce the thickness of Kevlar.
 
I'm with MarkZ and Zerodish. Flats are a real pain in the butt on ebikes with substantial batteries and motors. You have a motor, so just use tires made for motor vehicles. So what if it adds a few pounds and a couple extra pennies a day in electricity. It's definitely worth it to me, even if the only benefit was not having to add air nearly as often. Plus they're often cheaper than bicycle tires, since the manufacturers and shops treat cyclists like they're a bunch of suckers with their larcenous pricing.
 
John in CR said:
I'm with MarkZ and Zerodish. Flats are a real pain in the butt on ebikes with substantial batteries and motors. You have a motor, so just use tires made for motor vehicles. So what if it adds a few pounds and a couple extra pennies a day in electricity. It's definitely worth it to me, even if the only benefit was not having to add air nearly as often. Plus they're often cheaper than bicycle tires, since the manufacturers and shops treat cyclists like they're a bunch of suckers with their larcenous pricing.

There are other factors besides pricing and weight. It's a nuisance to mount and dismount motorcycle tires. You can encounter problems integrating hubs for thin spokes with rims for thick spokes.

Bicycle wheel parts can cost much more or much less than motorcycle wheel parts, but dollar for dollar, motorcycle parts are of lower quality. For instance, MC rims are single walled, without bead hooks. That's 1970s stuff in the bicycle world.
 
Chalo said:
John in CR said:
I'm with MarkZ and Zerodish. Flats are a real pain in the butt on ebikes with substantial batteries and motors. You have a motor, so just use tires made for motor vehicles. So what if it adds a few pounds and a couple extra pennies a day in electricity. It's definitely worth it to me, even if the only benefit was not having to add air nearly as often. Plus they're often cheaper than bicycle tires, since the manufacturers and shops treat cyclists like they're a bunch of suckers with their larcenous pricing.

There are other factors besides pricing and weight. It's a nuisance to mount and dismount motorcycle tires. You can encounter problems integrating hubs for thin spokes with rims for thick spokes.

Bicycle wheel parts can cost much more or much less than motorcycle wheel parts, but dollar for dollar, motorcycle parts are of lower quality. For instance, MC rims are single walled, without bead hooks. That's 1970s stuff in the bicycle world.

When it ain't broke, don't fix it. Sure moto tires are a bit harder to change, but once every 20k km or so is no big deal. My biggest issue with bicycle stuff (other than needing air all the time and much more prone to flats that can't even be rolled at the weights of my ebikes, much less ridden) is safety. ie Tires that last a long time have rubber that's so hard they easily lose grip. I've eaten asphalt a number of times, all on bicycle tires with stuff on the road (sand and dust or moisture) with which all of my moto tires have retained far more grip.

Sure you can be more careful in turns to avoid it, but one of my times was in a straight line on my long low (low makes the CG lower and things happen faster) cargo ebike. A dog being chased by another dog started to dash in front of me. It had rained earlier and the asphalt was almost totally dry with moisture visible between the pebbles. Out of instinct I hit the brakes and maybe turned the handlebar very slightly doing 30mph at the most. The bike instantly slipped and ended up on its side with me on top of it sliding to a halt with only a scrape on my ankle from the pedal and a slightly bent crank and scratched handlebar end as a result. It must have been quite a sight to the driver in the oncoming lane who luckily was distant enough to stop as I did all this and the sliding action made me and ebike drift slightly left of the centerline. He sees all this with a fat gringo (not a derogatory word down here) coming a meter or so from his bumper on top of a bike laying down in the road, who then gingerly gets up and checks himself before a thumbs up, and "gracias" for stopping and pushes the bike to the side of the road.
One of the dog owners was outside at the time asking if I wanted and ambulance, to which I said "no...gracias" and rode the bike home, straightened the crank and went ahead to the bank as originally intended.

If you have input on a ranging of slippery road conditions in your experience that would be appreciated. My only advice is to never ride around a pothole on the low side. I did that once directly in front of the emergency entrance for the nearby clinic. The road had been made with some tiny round rocks as a layer before asphalt. I went around such a pothole on the low right side and the bike went out from under me immediately like I hit ice. Nothing was even visible, and it wasn't until I rubbed my foot on the road in that area that I understood just how slick it made the road...like ball bearing spread on a smooth surface and it truly wasn't visible on the perfectly dry road.
 
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