Holy Exploding Tires Batman!

LI-ghtcycle

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Ok, so I have child carrier converted to a light cargo trailer (just tools enough to work on most things on a bike + electric components of an E-Bike) of undetermined brand (seems to be better than the bell's you get from department stores, and has until lately hauled bikes & tools with out trouble) that appears to have some weird defect of the rim.

(I will take pics tomorrow, my digi cam is charging)

Here is a stock online pic of the style of wheel:

s-l225.jpg


These are the typical 16" plastic mag wheels (converting to some skyway 20" UT Tough Wheels in the near future) but the WEIRD part is just today, having parked in front of the shop for work, the tire just exploded with maybe 20lbs of tools on it! :shock:

It has been very hot lately, (90 - 100F) so I am sure that factors into it, but with 110 PSI Maxxis Hookworms with pressure lowered to 50 PSI as an experiment (usually I was running around 70 PSI to give room for increases due to heat) this seems to have made little difference.

I have just given up on this wheel and replaced it, there are no sharp edges or any other obvious defects, other than some white stress marks (no cracks) inside the black plastic rim (not on the bead area just where "rim tape" would go if these were spoked) and at first I thought perhaps I was having the tires shift on the rim and pinching the tube, but it's a down right burst pattern on the tube, and not in the same place on the rim (this has happened 3x in the last couple of weeks, mostly while going down the road, but the one while parked in front of the shop just takes the cake! :roll: :lol: )

So my question to you who uses similar trailers with light loads (around 100 - 150lbs max) every day doing work or commuting duties, what wheels and tires are you using?

I am currently using 16" Maxis Hookworms.

Thanks!

Dayn
 
Pics of the damage on the tube?

Specific location on the tube each time?

Same tube brand/source each time? Or different?


On my trailers as on most of my stuff I'm just using whatever used stuff they either came with or off some other used bike or whatever.

For the bell-style trailers, they were mostly 20" wheels, and I've tried a few kinds, Not many flats, even when hauling the St Bernards or other even heavier (though less wiggly) cargo. All of them that I can remember were caused by thorns or road debris.

I *have* had one mystery explosion flat, on a bike, (CB2, IIRC) cause unknown, but leaving an asterisk-style hole in the tube. Long time ago.


Most commonly, though, is valve stems--either cheaply made and the rubber just comes off the brass, or damaged by valve hole issues in the rim, or too low a pressure and spins on the rim, etc.


Presently i'm using 26" wheels on the MkIV trailer (see signature link) with a tube, a slit-inner-circumference tube, then a tire liner strip, then a tire.
 
Finding a good tube seems to be getting harder. In 20",, it might be they just figure kids bike, and use the shit rubber.
 
If that's a Skyway Wheel, they have limitations to max pressure.
My 20" wheels have came with a sticker 60# max
my older 24"s have it molded into the rim.
 
This guy sells Skyway 16" wheels for his trailers:
http://www.bikesatwork.com/store/bicycle-trailer-parts

He's likely to have heard about it if its a phenomena.
 
If the tube has blown out, with radial splits at the hole, it blew when the tire crawled over the rim. Those are not hook bead rims. They can't handle much pressure. Plus they are slippery plastic. Add 100 degree temps to soften the plastic slightly, and you are asking for trouble.

Add several wraps of grippy, wide cotton rim tape to the bottom of the rim.

http://www.performancebike.com/bikes/Product_10052_10551_1168336_-1___

Tires come off rims when the bead slides down to the smallest diameter of the rim bottom, allowing the other side to clear the rim. This is what makes mounting and dismounting tires possible. If you add enough cloth rim tape to make it hard enough to require two tire levers to get the tire on, you will probably be OK.
 
Thud said:
If that's a Skyway Wheel, they have limitations to max pressure.
My 20" wheels have came with a sticker 60# max
my older 24"s have it molded into the rim.

Good point! I think I will probably just stick with what I have and/or switch up to 20" in the future after it's time to replace these hookworms.
 
gogo said:
This guy sells Skyway 16" wheels for his trailers:
http://www.bikesatwork.com/store/bicycle-trailer-parts

He's likely to have heard about it if its a phenomena.

Thanks for that link!

I hadn't thought of looking for 16" ones, I will have to ask him if the Skyway rims also have more of a rib than just a slick wall for the bead, that I am sure is my main culprit!
 
amberwolf said:
Pics of the damage on the tube?

Specific location on the tube each time?

Same tube brand/source each time? Or different?


On my trailers as on most of my stuff I'm just using whatever used stuff they either came with or off some other used bike or whatever.

For the bell-style trailers, they were mostly 20" wheels, and I've tried a few kinds, Not many flats, even when hauling the St Bernards or other even heavier (though less wiggly) cargo. All of them that I can remember were caused by thorns or road debris.

I *have* had one mystery explosion flat, on a bike, (CB2, IIRC) cause unknown, but leaving an asterisk-style hole in the tube. Long time ago.


Most commonly, though, is valve stems--either cheaply made and the rubber just comes off the brass, or damaged by valve hole issues in the rim, or too low a pressure and spins on the rim, etc.


Presently i'm using 26" wheels on the MkIV trailer (see signature link) with a tube, a slit-inner-circumference tube, then a tire liner strip, then a tire.

I will have some pics later today, heading to church shortly, but most of the bursts have been near the stem, however one was opposite, so I just decided to junk that rim (cut it in half at the valve stem so no one would accidentally use it) and replaced it with another used rim from a kid toting trailer in the shop.
 
Warren said:
If the tube has blown out, with radial splits at the hole, it blew when the tire crawled over the rim. Those are not hook bead rims. They can't handle much pressure. Plus they are slippery plastic. Add 100 degree temps to soften the plastic slightly, and you are asking for trouble.

Add several wraps of grippy, wide cotton rim tape to the bottom of the rim.

http://www.performancebike.com/bikes/Product_10052_10551_1168336_-1___

Tires come off rims when the bead slides down to the smallest diameter of the rim bottom, allowing the other side to clear the rim. This is what makes mounting and dismounting tires possible. If you add enough cloth rim tape to make it hard enough to require two tire levers to get the tire on, you will probably be OK.

That makes perfect sense!

I suspected something along these lines, but now that you mention it, I was thinking of going spoked for that very reason, I will try the grip tape!

I had a tube burst while installing a new tube, and adding the heat on those slippery plastic wheels, would absolutely allow for that!

I wonder if there are similar mag wheels that DO have a pronounced lip, I was only considering buying the Skyways as they are well known for taking a lot of punishment, the low maintenance of mags, and increased ability to take a load.

I had burst "asterisk" shaped hole just like you describe AW, and this has happened at least 2x on the left rim (which seems to be the main suspect) but I wish I had written it down, but I am pretty sure the right one has burst once too.

I will try the grip tape asap, for now the trailer will be parked in the cool garage.

The MOST annoying thing the other day, I had JUST come home from work, was preparing to visit a customer who needed a minor repair on his E-Bike, and then discovered I was running on a flat!

I suspect it had gone flat as I went up my driveway, but I never heard the "pop" usually it's pretty loud! :roll: :lol:

Anyway, by that time (around 6pm) it had cooled down to around 80F and I was able to poke along at around 10 mph and be ok, but MAN! what an annoyance!

What would be the MPH you all would recommend to cruise with 16" wheels? I generally would like to average around 15 MPH, but the bike is of course capable of much more, just want to avoid being harder on them than as I realize they are spinning much faster than my bike's 24 x 3.0 tires. :)
 
Oh wow, I feel dumb, I have another kids trailer just parked along the garage that I used to use to hold 3 car batteries years ago when I was testing out the first E-Bike I ever built for my dad ... I bet THOSE rims won't have any trouble lol!! :roll: :lol:

Or at least might work as spares!

The shop I work with is now completely out of 16" tubes ... wonder why? :p
 
WOW!!!

I just called the guy from "Bikes at work" expecting to just leave a message, and apparently, I should have just held out for the Schwalbe Big Apples I wanted in the first place!!

Apparently, Maxxis Hookworms are known for NOT holding onto the more slippery plastic rim, but the Schwalbe marathon & Big Apples do fine!

I am SOOOOOO tempted to use the company card right now to just order some Big Apples!!! :lol: :twisted: :mrgreen:

Well, off to church for now, thanks everyone!
 
dogman dan said:
Finding a good tube seems to be getting harder. In 20",, it might be they just figure kids bike, and use the shit rubber.
The Walmart here in Alamogordo has loads of 20" super thick slime tubes.
 
If you can modify your trailer to hold the wheels above the deck, I can highly recommend rebuilding it to use 26" wheels--there's a lot of ride improvement, and a much larger selection of tires and tubes than you may find for 16" bicycle rims. ;)

It will go over bumps better, be less likely to get a tire / tube pinched upon hitting the far edge of a pothole or curb, etc.

Plus the wheels themselves will be stronger, with more spoke length to soak up the abuse, etc.

The MkIV trailer so far has been much better than previous ones, in all of the above. I used 26" wheels in one prior trailer (Hachi's MkI version) but it was tippy because I put the bed above axle height---Yogi's MkIV doesn't have that problem mostly because the bed is down as low or lower as if it were 20" wheels, but also because it is wider (only because I needed more space for him and his kennle/crate).

In between I used 20" wheels for MkII and MkIII, and while they weren't tippy they had terrible ride quality for doggy-carrying and heavy cargo. :/
 
amberwolf said:
If you can modify your trailer to hold the wheels above the deck, I can highly recommend rebuilding it to use 26" wheels--there's a lot of ride improvement, and a much larger selection of tires and tubes than you may find for 16" bicycle rims. ;)

It will go over bumps better, be less likely to get a tire / tube pinched upon hitting the far edge of a pothole or curb, etc.

Plus the wheels themselves will be stronger, with more spoke length to soak up the abuse, etc.

The MkIV trailer so far has been much better than previous ones, in all of the above. I used 26" wheels in one prior trailer (Hachi's MkI version) but it was tippy because I put the bed above axle height---Yogi's MkIV doesn't have that problem mostly because the bed is down as low or lower as if it were 20" wheels, but also because it is wider (only because I needed more space for him and his kennle/crate).

In between I used 20" wheels for MkII and MkIII, and while they weren't tippy they had terrible ride quality for doggy-carrying and heavy cargo. :/

Good point!

I will probably build or have built a custom trailer at some point, but for now, I will use the better tires for these rims, and I have a set of spare ones on an old trailer I will modify, I will try just making some groves on the inside of the rim for the bead to hold onto until the better tires with some coarse sand paper and see if that helps.

I will take pics if anyone is really interested, but at this point after talking to the guy from Bikes At Work http://www.bikesatwork.com/about/history earlier this morning, he confirmed my suspicions that the tires were simply slipping out of the rims.

I do believe that one rim was particularly at fault however, since the tubes broke at least 3x on that one rim, and I have lots of used wheels to modify for this purpose, so that will be the cheap route for me at this point, until the tires are delivered at least.

Thanks again for all your help everyone!
 
Mag wheels of all kinds lack a hook bead-- the raised lip on the inside edge of each rim sidewall that interlocks with the wire bead on the edge of the tire. This limits the usable pressure of the tire to less than the tire's rating. As an example, 27 x 1¼" tires are usually rated for 90 to 100 psi, but on a steel 27" rim without hook beads, over 65 psi is not recommended.

The elasticity and slipperiness of the material in nylon mags only exaggerates the limitations imposed by the lack of hook beads.

If I remember correctly, Skyway Tuff mags are rated for 40 psi.
 
Makes sense, thanks for the tip! I will keep the pressure lower and see what happens.
 
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