I’m gonna tag on and offer to people who bought new iwonders and are scared to use them, I will help you dispose of them for free and you will get a rebate for 50% of the original purchase price. 
3 Likes
I have 2 and a half wheels for you!
2 Likes
One thing that you could try, which I think was suggested earlier in the thread, is to fill the spokes with something like this Window Weld or some other similar PU adhesive goo. I think this stuff is around 90A hardness, and at worst it would probably slow the catastrophic failure long enough to safely stop, and at best reinforce the core so it never happens in the first place. Obviously, front wheels would be easy to fill, back ones a little more challenging unless you wanted to basically glue a pulley in, but I’d rather have a rear wheel fail than a front wheel.
https://www.amazon.com/3M-08609-Window-Weld-Urethane-Cartridge/dp/B000FW61EW
Thanks for the response
Should of bought 110s in the first place? 
USA made wheels even cheaper then China thane.
12 Likes
This wheel is same wheel form iWonder or SR. IWonder make mold for these. Core material is PC/ABS. Original ABEC is Nylon+25GF.
4 Likes
Update.
I had not checked this before…
One of my Zealous bearings I had taken out of the cloud wheels was totally seized up.
I can’t say for sure it was from the front wheel that broke. But it is from the board…
3 Likes
Is it harder to bond urethane to nylon? Is that why they used PC? I can’t imagine it is for material cost…
Do you mean a mix of PC & ABS? I guess a high density nylon might be significantly stronger than PC.
How do you know these things? Spec Sheets? A contact at the factory?
Ironically polycarb has a higher tensile strength and impact resistance than nylon. but gf nylon should be stronger and more flexible…
PC+ABS.
I been to factory before.
1 Like
Pc+ABs is cheaper than nylon+gf.
It is, but not massive difference given how much material is in the core vs cost of the wheel?
For mass scale and tooling is cheaper. Tooling nylon+gf is more expensive than PC/ABS.
Injection molding? What’s their scale of production? I didn’t think there was a mass market for gigantic 120mm urethane wheels 
For nylon+gf it need harder tool steel. They make more than 15k of this wheel already.
I also see prototype for 140mm version. But they no let me taking photo.
3 Likes
holy shit
Holy shit again…
Makes sense I guess. I was guessing it was gf nylon, wasn’t sure. Since it’s PC abs it kind of makes sense its more brittle in cold
2 Likes
No friend 
3 Likes
I see no reason not to take Jeff at his word, that he’s been there and that he knows the ingredients. His facts seem credible. Conventional Cores are injection molded with glass fiber reinforced Nylon. Iwonders cores are injection molded with a Polycarbonate/ABS mixture because it is less expensive to manufacture the molds with softer steel.
So those facts certainly line up with the pictures of the failed cores. Depending on the ratios of PC and ABS, the cores might shrink more after being removed from the mold. This would explain the inconsistent fit with wheel pulleys. The ABS content also explains the poor resistance to the cold and the stress fractures.
So I think it would be fair to say that the i-wonder wheel cores are manufactured with materials that are significantly weaker than conventional wheels–at they same time as they are likely subjected to higher loads due to the large diameter and curved profile. Conventional wheel cores are supported by a relatively dense PU wheel body. I-wonder Cores don’t get that extra support because their wheel bodies are spongy. So we would expect higher loads at the outer edges of the I-wonder cores.
All in all it does not add up to a product that will last. The time to failure would be much shorter with heavy riders, rough terrain, higher speeds and cold weather. Two months and 200 kilometers looks like the shortest time to failure.
Due to inconsistencies in the core thickness and perhaps also the PC/ABS mixture, some wheels may fail much earlier.
Is that a fair summary?
2 Likes
If correct cooling is not apply when moulding the core it will shrink at different rate. Because they make core in different batch and is now finish winter in China I think this can also be effecting result.
I think it can be fix with some mould change to add some thickness to core. Is easier to adding material to mould than removing so no need new tooling.