Chinese Carbon MTB Forums
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Re: Ultralight hardtails
could you share built specs to have a reference?I'll take a picture as soon as I can and post along with description of the main components. August 17, 2023, 09:44:04 AM |
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Re: Chinese Titanium Frames...
 I have about 2500 miles on my custom Waltly 29er frame. On my most recent adventure, I noticed that a crack has developed in one of the top rear triangle tube where it is welded to the seat post tube. I just wrote Sumi at Waltly, and asked what to do about this. August 18, 2023, 11:42:55 AM |
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Re: Recommendations needed on carbon fork cutting tool
I purchased a park SG-8 fork tube cutter about 30 years ago. Probably one of the best bike building tools I purchased. OF course, I paid maybe $25 for one and now they are close to $60
August 18, 2023, 03:12:22 PM |
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Re: Chinese Titanium Frames...
Wow that looks quite dangerous! I'm curious to see what will happen.I don't think it is dangerous leading to a catastrophic failure. It appears to be a stress crack right at the edge of the weld in the heat effected zone of the seat post tube. These types of cracks next to a weld are often due to improper purging of the area during welding where oxygen reacts with the metal causing it to become brittle. Sometimes this type of crack can be due to too much hydrogen in the area as well. August 18, 2023, 07:43:44 PM |
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Re: Opinion on these carbon spoke wheelset with dtswiss like hub
Hub story: I was thinking of having a lot of SuperBoost rear hubs manufactured. I contacted many "hub manufacturers" on Alibaba and discussed the hubs I wanted manufactured.. 1. I discovered that there are really only 3 companies in China that make 90% of the freehub bodies. I could select a "modular style" free hub that the hub designer would input the proper interface into the hub to fit the style I select. (Each style will let you also interchange between HG, MS SRAM, Campy.) 2. Almost all the hubs are CNC machined from Aluminum round stock. Many of the companies that design/manufacture/assemble/build wheels have access to common databases. All they have to do is modify a design from common proven hub design to meet their specific specification. (Hubs are a commodity these days.) 3. Very few hub bodies fail. What you have to watch out for is the hub machining and bearing fit into the hub, the brand/quality/class of bearings they install in the hub. (All cost driven) and that the freehub/cassette body is one that is of good quality. A lot of the stores/companies claim they manufacture and engineer their components themselves, but as I understand it, many of these companies have common ties to each other, common machine shops and source parts back and forth between each other. China is a communist country, and the government has set up a system based more on cooperation between companies rather than by individual competing businesses. I've found too that many smaller manufacturers in China are held by larger holding companies. These holding companies in turn are held by even larger companies, eventually rolling up to some sort of government backed entity. Its one way they can outfit smaller companies with the resources they need (like manufacturing equipment.) Based on all of the above, when they say they make their hubs "inhouse", this means to me that they purchase the freehub bodies, axles, bearings, and other hub parts, and that they may have modified an existing hub design, and farm out the fabrication of the hub to an affiliated CNC and finish shop. All they do is assemble the hub into a finished assembly. Thus, it is difficult to assess the quality of the hub set they are selling. I've been using Chinese "no-barnd" hubs for years, and have only had issues with the bearing on one front hub. I always ask them the specific brand of bearings they use, and who's freehub they are using. I also ask to see the machining specification of the hub where the bearing are fit into the hub body, and what quality control they have in place to be sure the bearing fit is correct. (Sometime it takes weeks before I am satisfied that the hub is actually being properly machined to the specification required for proper bearing fit.) I have also purchased a hub knowing I don't like the bearing brand they use and I have replaced the bearings myself to a better bearing once I receive the hubs. August 20, 2023, 12:20:59 PM |
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Cracked Waltly TI 29er frame Repair
I discovered that my Waltly custom 29er TI frame has some bad cracks in the seat stay to seat tube. Sumi, at Walty, has proposed 2 approaches. 1. Send the frame back to China for repair. 2. Split the cost of a new frame 50/50. I want what will be the most cost effective approach to either repair or replace the frame. I need input from the forum to help me figure out the best approach. - Does anyone know of a US shop that welds and repairs TI frames? If yes, what is the typical cost to weld/reinforce/repair the cracks? - Does anyone know a cost effective way to ship the frame back to China/Waltly. - Looking online I have found shipping estimates between about $400 and $1200 - I believe that a 50/50 split for a new frame could cost up to $700. Thanks. August 22, 2023, 04:30:40 PM |
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Re: Interesting Aliexpress finds! - good deals, interesting stuff, new products etc!
Articles I've read state that all carbon front chainrings last longer than expected. I read that one can get up to about 10K miles on the Road. Many have commented on how well they were wearing at 3K to 5K miles. I do not see many follow up reports on if the actually get 10K miles out of them September 04, 2023, 03:56:36 PM |
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Re: Running MTB wheels on gravel bike
This is where I began. Looking at a recommended ID rim width versus tire width chart. https://www.wtb.com/pages/tire-rim-fit-chart Depending on the generation of gravel bike frame you have, you may only be able to install up to 40mm wide tires. New generation gravel bike frames can be purchased that will fit up to 2" tires / 50mm tires. (Remember that the wider the rim, the less side wall bulge you might have. This can lead to rim damage if you run too narrow a tire on a wider rim.) I started out thinking I could use my gravel bike for gravel road bicycle touring and discovered that my gravel bike was limited in how I could configure it and that it beat the heck out of my upper body descending. If you want to participate in "bikepacking rides / events" where you carry a minimum amount of gear and are riding for fast "best known times" then you will want to ride on as narrow tires as you think you can get away with. You will want 700c rims with an ID between 22 and 24mm. It you want to bike pack on rough terrain where there is a lot of chunky, washouts, washboard, and overall crappy riding conditions, then you might think about a 29er hardtail with rigid fork that will fit 2 to 2.2 low rolling resistance tires. I built up a 29er hardtail that I run either a rigid carbon fork or a suspension fork, and use drop bars on this bike. It served me well for over 1000 miles of camping this summer. Take a look at what the 2023 Continental Divide riders were riding to get a feel for what will meet your needs. https://bikepacking.com/bikes/2023-rigs-of-the-tour-divide-breakdown/ September 04, 2023, 08:31:56 PM |
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Re: Running MTB wheels on gravel bike
Forgot, here are 2 Aliexpress stores where I have purchased carbon rims from. (Happy so far with the wheels I built using these rims.) https://www.aliexpress.us/item/3256802372131445.html?spm=a2g0o.order_list.order_list_main.615.6f7d1802HFG0Z2&gatewayAdapt=glo2usa4itemAdapt https://www.aliexpress.us/item/2255800282655021.html?spm=a2g0o.order_list.order_list_main.105.6f7d1802HFG0Z2&gatewayAdapt=glo2usa September 04, 2023, 08:40:15 PM |
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Re: Interesting Aliexpress finds! - good deals, interesting stuff, new products etc!
Fantastic find! I already ordered a pair. I found a link to an even lower price and with coupon paid $41.62 https://www.aliexpress.us/item/3256805804769674.html?spm=a2g0o.order_list.order_list_main.5.2b8d1802PPhYSb&gatewayAdapt=glo2usa September 05, 2023, 03:45:29 PM |
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