How do I test my $120 full carbon ebay fork?

Hello there :slight_smile:

I’m gearing up for a gravel race and have decided to use my hardtail. Because it’s not super rough and I’d like to save some weight, I got myself one of those full carbon 700g forks from ebay. It’s not quite race ready yet…I need to cut the brake cable and run it internally…but it was enough to get out for some road riding today. And…no problem, the fork feels fine.

But how do I stress test this thing? I’m going mountain biking Thursday…if it survives some decent mountain biking then I should be good to go for gravel…right? I don’t have access to X-ray or ultrasound but the fork looks perfectly fine on the outside.

Thanks!

Joe
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Body armor, knee pads, elbow pads, full face helmet.

Full speed into a wall? :stuck_out_tongue: Take a few jumps at the nearest bike park?

Seriously, no clue. I think it’s just if you survive, then it’s good. That said, I’ve used “one of those” on mild terrain on my first groadie, with a carbon steerer no less. I didn’t have problems. It was always on the back of my mind that it’s going to snap, same with the handlebars.

I think for something like gravel, you’ll have probability on your side.

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I guess this brings up another question…does anybody know of anybody who has broken one of these ebay things JRA (“just riding along”)?

Joe

There’s no ISO testing on these things - often times what happens is that the molds from legit companies are used, illegally, after hours to pad someone’s “business” not all cheap carbon is the same and there’s no way of knowing if you’ve got a fork that has more resin than carbon strands. There are plenty of success stories and while I’d wager you’d probably be fine on this thing for gravel, there’s no way of knowing for sure. I wouldn’t run one.

You voted for “value” in place of peace of mind I’m afraid. Unless you know a buddy with an X-ray machine?

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Huck it to a flat PinkBike style

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I do have a buddy with an X-ray machine but I’m not going to be near her shop until after the race. Can you see the layers and such by X-raying it? I like your idea though…I might have to bring it along next time I see her.

Joe

LOL, I voted “available” in place of peace of mind! :wink:

Joe

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As someone who x-rays things for a living, the short answer is no. Or rather, if you x-ray it with enough resolution to see anything more than obvious damage, you can only cover a very small area of maybe an inch at a time. You might still miss delaminations for example. X-raying might show you if there is any of the tubes ir doam left they used for forming the part, or if there are larger impurities in the carbon.

One simple way to test a carbon part for damage is by tapping it with a coin or even just your knuckle. If the sound turns dull, in a place where it shouldn’t, something might be up. However that really helps more to find cracks under the paintwork after a crash etc. Another way to test is with ultrasound.

Also, not all cheap carbon parts are made illegally after hours. Quite a few simply come from smaller companies, using “open mold” design. Those are molds that have no patent or where the patent is expired. It doesn’t mean it’s wrong, it could simply be an older design. There is also a lot of carbon expertise in China, a lot of money (private and government) that goes into design and development, and a lot of those newer companies try to sell via ebay and Alibaba. It doesn’t mean all their products are bad.

(I’ve build me xc bike with a Chinese carbon frame, bars, and seatpost, it hasn’t broken yet.)

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Fair response. :slight_smile:

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Hey guys, I’m happy to report that the fork survived the Oregon Trail and, being an XC mountain bike, I was able to hammer it on some washboard descents. If I ever do that race again…which I won’t…I’ll leave the sussy fork on, it was that rough in places!

So tonight it’s late and ebay is just sitting there and one thing led to another and now I’m looking at one piece handlebar/stem combos. In the neighborhood of 260-ish grams for the piece. Like $50, some are cheaper.

Has anybody used one of these? Did it break? Has anyone ever known one to break? I know it’s probably a bad idea but…is it really another bad idea?

Joe

PS I won’t go back to the Oregon Trail because of me, not it. I’ve found…I like beds. I’m a fan of my bidet. I guess I’m not much of a camper. Oregon is a long way from Florida! But the route and especially the organizational team…really 1st class. We had some crazy heat out there, well over 100 on the last day, and they didn’t turkey out and shorten it, they just added a water stop and let us people just trying to survive start earlier. It was an epic experience in every way.

As someone who went down that rabbit hole a while back, I’d say be very cautious. Whilst I didn’t see specific examples of the Illicyc or other Chinese one piece stem and bar combos breaking, there were enough horror stories of Chinese Carbon bars and overly light stems snapping. Other parts (like rims and hubs which I’ve been very tempted by recently) are a little less catastrophic, but if bars go there’s little recovery from that. Tales of dental surgery etc abound.

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Relatedly to this and your post in the Epic Evo weight thread; have a look at Mt Zoom. Crazy light weight bars and stem. If you’re game enough to try lightweight stuff and have a budget in mind that’s where I’d look first.

Again, do your research and assess your own risk. I ride a bit more aggressively (my assumption only) which basically steered me away from a stem change for the time being. I’d still look into an upgrade in the future but most the lightweight stuff is XC only.

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Yeah, your choices are ultrasound or X-ray examinations. Or if the damage is egregious, you could also use a borescope. Otherwise, I don’t know any (destruction-free) methods to determine the state of your fork. With carbon you usually don’t see any damage with your naked eye.

But seriously, why would you buy gear you are not confident in? If I don’t trust my gear, I won’t ride or corner as hard. No matter how cheap that fork was, it seems it wasn’t worth it.

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I tested my new (at the time) knock off Chinese gravel bike (bike shop friend of mine built up) by sending it down the smaller jump line at a local bike park. It survived some harsh feeling (I normally ride 170mm travel bike) landings on some doubles, but a couple years later I am still riding it.

Anecdote of N=1.

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There is a ton of manufacturing expertise in China, however if the company you buy from has no US legal entity, there will be no way to hold them liable if there is a defect. When you buy brand names you are paying for the marketing, but also sub-supplier vetting, quality systems and an entity your family can sue if they get it wrong.

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This wins the thread. Thank you! :joy:

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Torque it till it cracks then back a 1/4 turn. :slight_smile:

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Wow that stuff is insanely light…119g bars. And weight limit is 110kg too, kinda amazing.

Would you have any links or places to look for horror stories? I’d like to read them.

Yeah I really do NOT want that!

Joe

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