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Messages - Jerryno

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16
Cyclocross Frames, Wheels & Components / Re: Belt Driven Carbon
« on: September 01, 2016, 04:53:02 PM »
Nope, you won't find a chiner frame for belted cyclocross bike.

I hope you plan a single-speed, I am against transmissions in the rear hub. The only thing that I would approve is http://pinion.eu/en/. The transmission is in the right place, there is belt option, it has great gear range, it is weather proof & maintenance free and they have some frame options in carbon (not sure if cyclocross though).

If you find anything share the bike on the forum, it would be very interesting to see such build.

17
Vendor Discussion & Reviews / Re: Bicycle Companies Selling Chiner Bikes
« on: August 10, 2016, 01:30:31 AM »
It is untold secret of many small bike companies that they only paint chiner frames and sell them as own. Sometimes they source frames from different places in Asia.

For example this Pells X99 (http://mtbs.cz/media/2013/12/18/PellsF99_celk1_cl.jpg) was a copy of HongFu FM036. This Pells Duke XTR (http://static.vpress.cz/koloroku/495.jpg) is a HongFu-FM136. Both are highly priced race bikes.

The same with Kellys bikes, Superior, CTM, and many other small bike companies that operate locally here in Europe. It's not only carbon, they source aluminium chiner frames also.

18
29er / Re: Workswell WCB-M-062
« on: August 01, 2016, 07:36:51 AM »
Quote from: tingle3003 on August 01, 2016, 07:24:16 AM
My normal Ratio is somewhat around 2,9. Highest speed should be okay with something around 4.0.

Yes, that is also what corresponds to my findings. For the low-end I found 0.8 is enough. If you cannot climb with 0.8 ratio you cannot walk and you need to rest. TO have this range you need a 2x10 or 2x11 setup or 1x12 setup.

19
29er / Re: Workswell WCB-M-062
« on: August 01, 2016, 04:06:22 AM »
Your best option is the CS-MB001 frame that can accommodate up to 40T 1x11 chainring.

http://xmcarbonspeed.com/Productinfo.asp?f=1392

http://chinertown.com/index.php?topic=650.0

Usual MTB frames allow up to 36T 1x11. There is a thread about this here: http://chinertown.com/index.php/topic,627.0.html (in those days fast-geared MTB bikes were not a thing so a lot of discussion is about why the hell I would need a bigger chainring)

To have 50T chainring you need a 3xsomething setup for sure. Or you need a cyclocross frame with some big tires.

20
29er / Re: Jar_head's WCB-M-062
« on: July 26, 2016, 09:23:05 AM »
Hi Jar_Head,

here are my 2 cents for the design and process:

The stress is only distributed in couple of the strands (highlighted), whole lot of them are not load-bearing. This is because the bolts and carbon piece are at an angle. This makes the design weaker. I don't also feel good about those open holes (marked circle). In that area the strands rub against the edge of the bolt which is imho not good.



Look at this clamp how it is designed, I like this design much much more:



Also I suggest to run some software simulations or tests, or to make many many test iterations. Put too little carbon and the part will fail. Put too much carbon and resin and it will end up heavier than a piece from thin spring-steel.

It is also very good to press the part (vacuum or other means) to squish the excess resin out the part. The less resin inside the better and stronger part. Also if you cure the resin with some heat applied to it, it will cure into better resin.

21
29er / Re: Chinertown's 10,000th Post Giveaway!
« on: June 09, 2016, 04:52:09 AM »
Enter  :)

22
29er / Re: Chainstay badly hit during a ride
« on: June 07, 2016, 05:26:56 AM »
In the video the guy is not wearing any protection when sanding the carbon. He is only wearing gloves when putting the epoxy on, which is a good idea.

Carbon dust is not good - it is the same kind of dust as asbestos or silica, so some dust mask, goggles or gloves are good to have.

One small exposure will not hurt, most of fine particulates are caught in the moist secretions of the nose mouth and trachea and pushed up via small motile hairs on each cell until we can cough them out. But generally it is not a good stuff to be exposed to.

I'll just leave it here for any dyi repairers.

23
29er / Re: Painting/Finishing your Carbon Chiner
« on: May 19, 2016, 09:54:50 AM »
Quote from: Eugene on May 19, 2016, 08:00:28 AM
I'm now sure if it's ok to bake a carbon frame?

The powder paint is baked at 200°C. At this temperature the epoxy holding the carbon together will start to soften. Epoxy has no melting point..it just gradually softens till becoming goo at about 400-600°C depending on epoxy type and quality. I you really want to bake it you should fix the frame in place so it does not warp and hope they used a good quality resin.

The carbon itself is pretty heat resistant.

Carbon fiber composites can be powder coated as long as the resin (epoxy) has a Tg greater than 220°C (with the exception of special ultra-low curing powders that will cure at lower temps). The problem with powder coating carbon fiber without the aid of a conductive base coating is ANY surface defect (minor scratch, area of irregular distribution of fiber to resin, knit line etc.) will be amplified post cure. So it requires very good surface pre-treatment. And because of this is very expensive.

24
29er / Re: Design flaw/quality issue IP-036
« on: May 13, 2016, 03:18:26 AM »
@ PeterXu

The customer has business with you, not with the factory. If you set your business quality to be dependent on the factory, then you cannot control this and will be bad for your business.

You have $100 bigger margins than your cheaper competition. I suggest from this buy some frames to have for spare parts or when customer needs replacement. Also there are not that many things to check on a frame to see if it is good quality - you should check every frame and not send any that has flaws. You should know the product you sell well and you should know what to check on it. If you send a frame with short bolts it was your responsibility, not the factory.

If you only relay the problem to the factory, you are only a middleman, you have no extra costs (other than communication) from such customer service and ultimately you are not financially motivated to send good product.

I believe you provide the best communication experience, you probably get the better frames from the factory, but you only provide the same customer service as the factory when something goes wrong. For people in US, Europe, etc. such service is not enough and they are willing to pay more to have a better one.

25
Sales & Classifieds / Re: 256SL Frame * with problem *
« on: April 18, 2016, 02:56:46 PM »
How is it a warranty replace when you have to pay for it? Doesn't make sense.

26
Vendor Discussion & Reviews / Re: xmiplay warranty?
« on: January 25, 2016, 03:58:36 AM »
You are not the first and will not be last with exactly this failure. I am surprised they still sell this frame.

If contacting the seller does not help you can place a dispute with Paypal and hopefully get a refund for the frame. Then tell everyone how you were treated so nobody or less people will buy from that seller. That's how it works. The price is a lot less but the warranty is questionable.

Next time you buy you should research sellers reputation, for example I know Peter from XmCarbonSpeeds has a stellar reputation.

27
29er / Re: Deciding between 057, 256, or 041
« on: January 20, 2016, 03:04:07 AM »
I know you have reasons for every gram put off from your bike, but sometimes it can grow into obsession.

I can't feel 200g difference on my bike frame at all, but I can feel every 10gram on my rims and tires for example (and their stiffness too like you said).

Let's put that aside, we have different opinions here. What bothers me are the bolts.
Quote from: cmh on January 19, 2016, 11:36:25 AM
If you think "yeah but still, 6 bolts are safer", I'll ask why you don't safety wire every bolt on your bike, because that's clearly even more saferer. Maybe apply red Loctite 271 before assembling, then safety wire for the saferest! It's only a little more weight. ;D
It's not about making it safererer than designed but about not messing with the engineering of the guy that designed it. If the rotor would be designed for 3 bolts (there are discs like that - even designed for 4 bolts) I would put 3 bolts in. The argument shouldn't be "I am half the weight of a heavy rider so I can cut half the carbon from my frame, use half the spokes in wheels and half the bolts in brakes." The result of less weight is truly less stress but that means just less component wear. I've seen plenty bolts to wear out and snap (not on bikes though).

Forces in brakes are enormous even for light riders - the kinetic energy to be stopped depends on half the mass but quadrature of velocity! And I would ques that lightweight rotors are not exactly over-engineered. Even using 6 Ti bolts should be monitored with care because titan is not that strong as steel. I hope you are not using 3 Ti bolts, that would be just stupid even for light rider.



There are spokes in the brake disc and there are usually 6 of them (or more, never less) and they push against the bolts. If some bolts are not there and anchorage points are missing then that creates bending inside the disc that can add to the bending from thermal expansion and the forces on the remaining bolts can be in different directions than designed for.

28
29er / Re: Deciding between 057, 256, or 041
« on: January 19, 2016, 05:36:57 AM »
Is 200grams of weight really that much? If I eat a snack or take a dump my weight changes by +-0.5kg.

I always don't get weight weenies that for example are usually running just 3 brake rotor bolts instead of 6 just to save couple of grams. I would always go for safety and durability even if it's a little more weight.

The question I don't know the answer to is the durability of the 057 vs the 041. Searched about it and not much about the 041 out there. I would take the more sturdier frame. And if the more sturdier just happens to be also lighter that would be a bonus for me.

29
After The Ride / Re: Chinertown Strava Group?
« on: August 06, 2015, 03:26:50 AM »
I would join, but I gave up on GPS tracking some time ago. My phone always loses GPS signal in a forest and catches it back only when I stop. It's assisted GPS (most phones have this).

What do you use to track yourselves? A phone works for you or do you have Garmin's or other GPS cyclo computers?

30
29er / Re: IP-036 29er Full Suspension Carbon Frame Build
« on: August 03, 2015, 09:29:28 AM »
@Polo7

Did you consider putting your money into better wheels rather than better frame?

I bet you will feel every gram saved from wheels more than frame weight saving. If you need more comfortable ride go for the frame obviously.

Consider some carbon rims with tubeless light tires and the bike will fly.

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