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Are Cheap Chinese Carbon Frames Too Good To be True? | Ask GMBN Tech

September 11, 2019


(sword slicing against metal) – Welcome to Ask GMBN Tech this is our weekly Q&A session. So if you got any tech related
mountain bike questions, fire them into the email address at the bottom of the screen, or you can add those comments
in the description below. If you’re emailing us just use
the Ask Champion Tech hashtag in your subject header, just
to so we can identify them and chuck them in for next week’s show. So, first up this week is from Jake Evans. I’ve got a question, so if you’re setting a bike up tubeless the cheat way by using
extra layers of rim tape, could you theoretically
use Schrader valves like they use in cars? Not the tube ones, the
actual automotive ones, that you pull through the wheels. That’s a good shout. I want to run tubeless, but I want to run Schrader
valves as I prefer them. I mean, you can put air
and sealant through them, so it shouldn’t be an issue surely? One second, just gonna check one of these, yeah, as I thought, okay. All right, so on the screen now, you can see what I’m looking at here. So this is just an automotive
car tubeless valve stem. Not to far off the ones that
we have for mountain bikes. Now, all though this one is a Presta, not a Schrader one, the
principle is the same. When it goes into the rim, you have this little
rubber grommet or o-ring that sits up against the rim and then you have a retaining
nut just to hold it in place. And basically, if there are any air leaks it seals against that
and no air can escape and the valve can’t move, which of course if you can
move that valve accidentally, you can loose all your air. Now, with the automotive one,
unless there’s a threaded one that’s got thread all the way down, I don’t think you can, because you can’t fit a
retaining nut like this to it. However, if you were insistent on wanting to running Schrader valves, there’s nothing wrong
with that they work great. Stan’s actually makes a tubeless
specific Schrader valves and they are threaded all
the way on the outside. So you can just get those if you want to use your existing rims. But a good shout on the automotive ones. I might try to order a few sets just to see if there’s any variations. And if they work I’ll let everyone know. But I’m not sure they will as they are. All right, next up is
from Julian Grimaldi. Doddy loving the channel.
Thank you Julian. What difference in a bike
behavior would it make by putting of 140 mil fork
on a hardtail designed for a maximum of 120 mil travel? A friend of mine wants to
sell me his brand new 140 mil Pike RCT3 at basically half price I can find it anywhere else. My bike specialized Rockhopper Pro, it came with 100 mil Manitou Markhor. I find myself out of shock
travel pretty frequently. I would love to have a little bit more. Greetings from Argentina. Okay so, as a result of putting
a longer fork on your bike you will raise that bump
racket height slowly, you will slack in your seat angle, which means you won’t feel
quite as nice going up the hills because it pitches your
weight back further. You can compensate by putting
your saddle nose down slightly and running your saddle
slightly more forwards. And to the downside there’s also an upside and it’s slack in your head angle, raise the front end of your bike. So granted you could
lower your stem slightly or get a lower riser bar to compensate. But, on the upside it’ll feel
really good on the descent having that more control
on the front of your bike. Now, I was just looking at
some length of axles to crown, so that’s the measurement of
the entire length of the fork. So your back is a maximum of 120 mil, if I look at a 120 mil fork. So on-screen now is a little chart. So, 120 mil, 27.5 RockShox
fork axle to crown is 493 millimeters. Now, a 140 version axle to crown is 521. So that’s 38 millimeters higher. That’s quite a lot higher
than that 120 mil fork, which is quite a lot higher than the 100 you already have on there. So I would actually check out if you can shorten the
travel on that pike first. If you can run it at 120, happy days. Of course there’s nothing stopping you from running it a bit higher, but the extremity of going
from 100 mil to 140 mil won’t really change the
feeling of your bike. And I’m not sure it will be for better. Okay, so next up, this is really cool, this is from Didak Carbasa. Or Carvasa, sorry if I got it wrong. I’d like to know how a
freecoaster dirt hub works. I’ve seen many riders using these, so basically means they can pedal when they go fakie the hub doesn’t engage. Can you please explain how it works? I can’t show you because I don’t
have one here to take apart and show you. But essentially on a
traditional mountain bike hub if I get one of these out. The cassette of the hub,
basically your sprockets, they slide onto something like this and this will have pulls on it. When you pedal, they basically engage on serrated teeth on the hub. Turning the hub and propelling the wheel. When you stop pedaling the
springs go in and out like this. And this little spring pulls,
enabling it to free wheel. So on a freecoaster hub you can free wheel in both directions. And it works completely differently. And in fact, I’ve got some spare parts to fix a walker of Jack and it came in this and I kept this because I thought this would
come in handy at some point. So a freecoaster hub is a
completely different kind of fish in the way it works. So let’s just say the sprocket
is mounted on to this piece, which has a thread on it. Now, the inside of the hub shell will have a cone like profile and it’s basically like
a clutch on the inside enabling it to engage and
grip so you can pedal. Let’s say that this is that piece, but it’s shaped like this also. So when you put it into
the hub it can grip. And the way it works
is simply as you pedal it engages onto this and
it pulls it into the hub. As you free wheel, it undoes itself and disengages enabling the free wheel to actions happen in both directions. Kind of a hard thing to explain without having one in my hand. But that is the essential of how a freecoaster BMX style hub works. And then you can take up
the amount of slack you have can be adjusted so you can have
it very close or very loose. Now something you will find
with the freecoaster hub compared to a typical mountain
bike hub is the engagement of a mountain bike hub can be
as little as three degrees. It can be almost instantaneous. A freecoaster hub you can have almost half a revolution
before it engages. And that’s because it has to
pull itself back in again. So that’s the basic principle of how a freecoaster hub works. As scary as anything, but they do enable you to
do some pretty cool tricks. But no one currently makes a
dedicated mountain bike version that’s got these sort internals in them. This sort of stuff you tend
to see most people using are the 50 to one guys. They’ll have a blank
sprocket on the cassettes, so they’ll take off say
the 11 two for the bottom, have a blank sprocket and a change gears, so the chain drops onto
that and the chain actually just revolves around that. So it’s effectively decoupled
from the cassette of the hub. And in fact Neal ran this exact set-up on his bike to do a
little test a while ago. He said he wasn’t doing
it to get the benefit of the freecoaster backwards concept. He was doing it to
disconnect the suspension from the transmission. To get an idea of how a bike feels basically when it hasn’t
got a chain on it. If you wanna watch that
video I’ll put a link to it in the description below,
because it really quite cool. And there’s actually a couple of videos going up on GMBN soon. Basically have to sell
freecoaster at Chris, he’s gonna show you how
to do all those tricks. So keep your eyes out for
those in the coming weeks. Okay, next up is from Philip Schmidt. I know that the Cannondale
Lefty forks use needle bearing packs to not only keep the
inner leg from twisting, but because it offer a much
higher torsional stiffness and reduces stiction. I can see that this is not
necessary on a conventional fork but wouldn’t it also stand to benefit from needle bearings or some
other sort of linear bearing? Is there a reason why no one does this besides cost or weight? I feel pretty much today the
cost and weight, I recon. The Lefty actually came
from a twin leg fork, originally called, I think, the Moto FR. Now, rumor is that it was so stiff anyway that the mechanics were like, you can probably run this with one leg. And that’s basically how
the developer left it. Because it was so stiff that
they only needed one leg basically to accomplish
what they wanted to do. But that fork was, honestly,
completely bomb proof. And it was a six inch
travel fork, I think it was. Now it’s really popular
amongst tandem riders, the runoff for a tandem because it’s the stiffest
fork you can pretty much get and it will never ever break. But it costs a fortune to develop because those bearings surfaces
have to be so well made. Whereas churning out stantures or forks is a lot cheaper by comparison. And fork bushings are a lot cheaper, they’re very easy to replace,
they’re very fast to replace. I know for a fact that a lot of mechanics that I’ve worked with in the past, as soon as you mention the
account of Lefty service to them you just hear ugh and hear excuses. I’m going over here… Literally people don’t want to know, it’s such a love hate product. I’m a huge fan as you
probably know, anyway. But I’d be interested if anyone has ever worked
on something like this. But I just don’t think
there’s a need for it. No need for additional complications that you can get from that system. Of course Lefty has mastered the Ocho, which has got the three-sided system, so it’s substantially
lighter, easier to work on. But still, it’s a very
very expensive fork. And I can’t see a way of making
it work on a twin leg fork despite how well it would work. All right, next up from Boomerang Freak, I recognize your name, I’ve seen you before asking
questions I’m fairly sure. Hi Doddy.
Is it just me or is there so few
centerlock hubs out there? It seems that most brands
don’t bother about centerlock and go for traditional
6-bolt disc mounting. Would there be any reason for this? For I don’t know or care from
a maintenance perspective. Is centerlock the better option? I’m looking for a set of hubs
so I can use to build wheels. I’d love to have centerlock discs as most my other bikes also use those. And it’d be easier than simply swapping out
damaged rotors between bikes. I’ve got mixed feelings about centerlock. I love how it looks, it
looks nice and simple. I love the way you use a cassette tool to crank them on there, it’s really good. But they can rattle loose. Of course you can get around that using a little bit of thread lock. But it doesn’t help when you’re
riding someone else’s bike that’s got one that ends up
rattling loose, a bit of a pain. I had a quick look online, it’s actually quite a few brands out there that do offer centerlock hubs. Starting first up is a Hope RS4 hub, so they’re centerlock compatible. Next up I’ve got DT Swiss. Very much being the best for Shimano from the beginning of the
whole centerlock thing. So to have that one on
most of their wheels. Of course there’s Shimano, there’s another one on the screen. Then comes the cools stuff. Industry Nine, they’ve
got their hubs available at centerlock, super nice hubs. In fact their wheels are lovely as well. Then you’ve got White Industries, another sort of premium brand. Onyx or Onyx, the brand that made the silent clutch type super
fast engagement BMX hubs. They also do centerlock. And perhaps my favorite and if I could have any
hub right now on the list, probably the Chris King’s to be honest. But you do need a lot of
money for the Chris King hubs. They’re very expensive. I’m gonna be looking at some
Chris King hubs soon actually and the headsets next
and I want to explain why exactly they’re so expensive. Because they are insanely expensive when you look at them
compared to other products. Those in the know, know
why they are expensive and I want to share that with you guys. So from Angus Mclean. This question is for Doddy. I was looking on Pinkbike the other day, I found a post on Chinese Carbon frames. They look really nice and
seem to be really cheap. Are they too good to be true? If so, what are the downsides? You know, I was actually
looking online at AliExpress the other day and some of the other sort of direct sites like this
and it’s pretty funny some of the stuff you can see on there. I saw a set of forks,
they were 120 mil travel, they look, at a glance, like
a pair of forks three two’s. Extensions on them were like, they look very similar
should we say to Kashima, but slightly different color. And it had one appear to be
RockShox stickers on them that said fork shocks. I doubt what was inside those things. And actually, I think I wanna start buying some of this stuff. I’m gonna have to get a bit of a budget so I have enough for that. But I wanna buy a bunch of
stuff and actually check it out. Because it’s so easy to buy this stuff that I do know people that do it. And I actually worry about
the safety thing myself. So when you’re buying from a brand that’s already established
they’ve had their stuff tested to standards, so you know it is safe and it’s fit for purpose. When you’re buying this other stuff, you might get a really good bargain from a direct Chinese brand. But at the same time you don’t really know what you’re getting. So, you can get something really good, or you could get something that you’re gonna need a
new set of teeth afterwards. So honestly, I don’t know. I’m staying out of this, I don’t
want to recommend anything. But I want to find this out for myself and I want to do a feature
on buying this sort of stuff. Because this is something
that needs to be addressed, because in the past there’s
been lots of problems with fake components on the market. I know for example that
Specialized has a whole division of people and staff on
their team to take care of counterfeit products
which is a big problem for a brand like that. So in all seriousness, it is something that we’re
gonna look into doing here at Champion Tech. So I think it’s a really
good feature, it’s fun, we’re gonna see what it’s
all cracked up to be, and if it is as good as
it sounds like it is. Gimberli you know the saying, if it looks to good to be
true then it normally is. So I’d be cautious on that one my self. But you might get yourself a bargain. Okay, and last up this
week is from Joseph Tinsay. Is there a difference between
the Teflon coated cable compared to the stock cable? You’re obviously referring
to the gear in the cables. Yeah, basically a Teflon coated cable is going to remain operating
a little bit smoother for a little bit longer in typical usage. So most cables are stainless steel and they will slide nice and smoothly through that outer housing. But the outer housing can ingest gunk, which hampers that. And then of course you
get the non-stainless, the cheaper inner cables and they can actually corrode slightly so you get yourself in
rather a pickle with those. Over time with the amount
of crap they ingest into the system. So a Teflon cable will definitely
last a little bit longer and go a little bit smoother. All that’s nice. I use stainless ones, I
just look after my bike and make sure I’ve got
ferrules on everything. And I think really the only way to make it totally maintenance free, is get a dedicated sealed system. Now, Fibrax makes them, there’s
one on the screen there. Gore used to actually make them, I’m not sure if they still do. But they make completely
sealed cable systems. And they’ve got an inner
liner, they’re amazing things, and they cost quite a lot of money. But if you really suffer from that problem with cable shifting in, let’s just say, winter conditions, then maybe a system like
this is really good for you. I used to run the Fibrax system, I was amazed how long it stayed working while jet washing the bike, generally not paying much attention to it. No problems with shifting whatsoever, so that’s fundamentally the difference. Stainless cable will do
the job just as well. You might just need a
little bit more maintenance. So there we go, there’s
another Q&A session in the bag. If you’ve got any questions or comments, leave them in those comments below. Let us know what you think. Let us know what you want to know. For a couple more Tech raid videos, hit them up right down there
on the bottom of the screen. And of course, don’t forget
to give us a thumbs up if you like the channel and subscribe if you haven’t done so. Cheers guys.

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