Wire bead failure

[Fabian]

This time i managed to catch a wire bead failure before it failed when out on a ride:














unlike the time when this happened:

http://motorizedbikeforum.the-talk.net/t202-macgyver-ing-it

 

[grinningremlin]

Looks like something may be funky with your rim, with the parallel wear on the inside of both sides of the tire.

 

[Fabian]

The original failure occurred on a Quando rim, and this wire bead failure has occurred on a Shimano rim. Both wire bead failures have been on the rear wheel, and i put a heck of a lot more torque through the rear wheel than most people.

I also run my tyres at low pressure (20 PSI on the front and 24 PSI on the rear) because (for me) comfort is far more important than speed or longevity of the tyre.

 

[FurryOnTheInside]

Idk how you put up with the squirming when going around corners, and presumably alll the time when you're applying torque. I've run as little as 17.5ish in a front and about 22.5ish in a rear tyre (not that my pump's guage is accurate at that pressure range), but those were 2.5" and 3.0" tyres and the squirmy feeling was not comfortable at all and it was very hard work to pedal even just really short distances on the way back to where I got off to walk & push back uphill. It did also pinch flat going down the up escalator in the railway station (I was a very immature 21 year old haha) after getting the train back from the woods I rode in.

Actually now I'm wondering.. How the heck have you not ripped the valve stem off your inner tube yet?

Would you consider trying a tubeless-on-regular-rim conversion system and why/why not?

 

[butterbean]

Do you have such rough roads where you live, that it's absolutely necessary to inflate your tires to only half the recommended psi? Sorry, but I'm not understanding this. I run hybrid tires at 40 psi, and my bike rides smooth as butter. I would think that you would have a greater benefit in the area of comfort from an appropriate seat and/or suspension seatpost combo, than from improper (and yes, I would unquestionably call half the recommended psi improper, as also evidenced by your repeated sidewall destruction) inflation of a tire that's already designed for a smoother ride. Btw, the tires I run are Kenda K838's, and they ride much smoother than the knobby tires I used to run. I'm sorry, but with that low tire pressure, your tires must not last very long at all. I'm really scratching my head over this one.

 

[butterbean]

Inflating your tires that low can have no possible advantage, neither in comfort, power, mileage, stability, or any other way that I can think of. There is a point where tire pressure can be so low as to have no traction at all, and if you're not there, you're close. Even for winter bicycling in the most slippery conditions, 5 psi less is usually what's recommended, no more.

 

[Fabian]

Idk how you put up with the squirming when going around corners,

There was virtually no squirming at all. If there was i would have done something about it, and i am still surprised at how true the tyre was running. All it had was a small tread and sidewall deflect of about 1/8 of an inch when rotating, and i never felt any wobble when high torque was passed through the wheel.

I'm wondering.. How the heck have you not ripped the valve stem off your inner tube yet?

I run thorn proof tyres with slime; completely preventing pinch flats and flat tyres in general. I am surprised at how well they do their job.
I have had the valve stem rip out of two tubes in the 50,000 kilometers (31,000 miles) that the bike has traveled, and in both cases they were on the front wheel, which i run at 20 PSI.
I was typically getting 10,000 kilometers (6,000 miles) out of a thorn proof tube before the valve stem seperated from the inner tube. For that reason, i replace my front tube at 8,000 kilometers (5,000 miles).

Would you consider trying a tubeless-on-regular-rim conversion system and why/why not?

I think that going tubeless has many benefits, but i like the idea of a thick thorn proof tube giving the wheel rim some cushioning if the tyre may happen to kiss the rim.
In my situation, thorn proof tubes have proven to be so reliable, i just haven't bothered looking into an alternative method, because there hasn't been the need to do so.

the rim could have a flat spot by now of course, it must have hit the ground a good few times.

Your assessment is correct. There have been a few times when the tyre and tube has impacted the rim, but it hasn't been a forceful impact, and the wheel rim doesn't have any crush spots.
I happen to have a wheel truing jig; enabling a visible check for runout in all dimensions.

 

[Fabian]

Do you have such rough roads where you live,

Yes i do, and i spend good time finding them, but i match my speed to the road conditions. I would rather travel more slowly, yet do it in more comfort using lower tyre pressures.

Sorry, but I'm not understanding this

I prefer comfort to a rough ride. My preference is for the tyre to partially soak up the bumps. Unfortunately my bike frame only allows a max tyre width of 2.25". I would prefer to have proper balloon tyres in a modified GT LTS frame. That would be the ultimate in comfort, but the lions share of engine power would be used to overcome rolling resistance. That said, rolling resistance doesn't worry me, because speed is not my goal.

you would have a greater benefit in the area of comfort from an appropriate seat and/or suspension seatpost combo

My bike is installed with a super comfy gel-seat and the best suspension seat post on the market; fitted with the softest and most comfy long travel elastomer available: Cane Creek Thudbuster

they ride much smoother than the knobby tires I used to run

I need tyres with an off-road pattern because i spend a lot of my time riding off-road.
The lower tyre pressures assist with traction, especially when negotiating your way down hills on semi rocky surfaces. The tyre much better wraps itself around surface protrusions, giving more slow speed control when hard on the brakes on nasty (off-road) inclines.

with that low tire pressure, your tires must not last very long at all

Typically i get 3,000 kilometers (1,860 miles) out of a front tyre and 1,500 kilometers (930 miles) out of a rear tyre, and that's due to the tyre tread surface wearing out.
For the most part, wire bead problems aren't an issue, though this is the second tyre (in the many fitted to my bike) that's had a bead failure. Overall, it's not a bad number, however, you have no external indication that the wire bead is starting to fail from an outward inspection of the tyre.

Inflating your tires that low can have no possible advantage

Primarily advantage = comfort. 24 PSI is the lowest pressure i can go for my weight.
I will agree that low pressures greatly accelerate fatigue and premature failure of the wire bead. Having said that (and for the most part), the tyre tread wears out before the bead fails.

 

[butterbean]

I wouldn't want to spend that much on tires. I pay almost $20 a tire, and if they wore out after 1,000 miles, I would be upset. As it is, they look brand new after about 600 miles. They have a groove tread like motorcycle tires, designed to let water flow through the channels to avoid hydroplaning. They are 1.95". Best tires I've ever had. They can inflate from 35 to 85, and I run them at 40. With 35 being the lowest recommended, they are softer than the ones you run, so you could probably run them at 30 and get decent traction as well as comfort. But inflating a tire that is recommended at 40 to only 24 seems like it would do more harm than good.

 

[Fabian]

They have a groove tread like motorcycle tires, designed to let water flow through the channels to avoid hydroplaning. They are 1.95". Best tires I've ever had.

You are concerned about hydroplaning on a motorized bicycle when it's traveling at 25 miles per hour?

Are you regularly riding through deep water rivers?