Will Your Rim Brake Road Bike Be Obsolete In 5 Years? | GCN Tech Clinic #AskGCNTech


(metallic whooshing) – Welcome to the GCN Tech Clinic. If you do have a question
that you’d like answered on the Tech Clinic, drop it
down in the comments below underneath any of the
shows throughout the week, using the hashtag ASKGCNTECH. That is the best way
to have your questions answered on the show. Right, first up is Al Francis. What is worth buying? A full carbon wheelset or a
carbon wheelset with aluminum braking surfaces. What are the advantages
and disadvantages of both? Well, first up is good
question because it’s one that many people would have had
to have asked over the years. Certainly 10 years ago it
was a really big topic. If it was me, I would always
opt for the full carbon wheel, but I probably wouldn’t
want to ride it in the rain purely because the braking
performance is wildly diminished in the wet. And that’s because carbon just
doesn’t really have a great surface for braking unfortunately. Manufacturers have tried
many different things but it will never be
quite as good as aluminum. So, if it was in the rain
and you’re going to ride in the rain a lot, imagine if you live in the UK,
then you probably want to opt for the aluminum braking surface. Though, this is neither a here or there, it’s kind of like a halfway house between two different types of wheel. It’s simply an airless strip
that’s been glued onto a rim. And I’m not sure that it’s
necessarily the best design. It’s going to be a little
bit heavier and potentially not quite as strong, and it could over time
peel away from the carbon. It has happened, I have seen it before, but you will definitely
have better braking. It’s up to you I guess. Do you prefer weight? Or do you prefer braking performance? You see, it’s quite a conundrum really, and it’s a difficult one to answer. So I would probably try
and get a bit of a test on both sets of wheels if you can. Or meet some of the local people
out and around in your area and see what they prefer to ride. That’s probably the best
gauge that you’ll get. Jockdoc07 is up with a
question which I quite enjoy answering or thinking about,
because it is something that I’ve experimented a lot
with over the years. Now, he wants to know what is
the physiological difference between a 170 and a 175 mil crank. Now, scientifically speaking,
the difference is only… Or mathematically speaking, the difference is five millimeters. That means from top to
bottom of a crank stroke, that’s a whole centimeter. And that’s quite a big
difference and it adds up. Imagine you’re calculating that cadence around 60 to
80 for an entire race, so five to six hours, that means your muscles going to
be traveling that much further on those longer cranks. Which will add to muscle fatigue. It’s also going to be less aerodynamic, and that also adds up as we know. Thank you Ollie for your efforts in the wind tunnel recently. It’s also going to affect
your bike fit and position. If you have a shorter
crank, you can afford to get more rotated into a more
aerodynamic position which is something a
lot of people are after. Now, for me personally, I found
actually that shorter cranks are much more comfortable, I
have much less muscle soreness, and I seem to recover from
efforts without losing any power. Shorter cranks are
supposedly more efficient, though this is somewhat,
I don’t know okay, the studies are quite inconclusive. A lot of people seem
to argue for or against when it comes to the efficiency. So perhaps that’s more dependent on the style of rider you are, or the body type you have. If it was me, I would always
go for the shorter crank. You’re very unlikely to
see any disadvantages from using a shorter crank. You’ll also get to spin
that little bit faster because your legs be
traveling short distance. On those Penny-farthings that we rode, we had 100 millimeter cranks. And they were tiny, but
it definitely helped. And you can really notice the difference on a Penny-farthing. If you had longer or shorter cranks. And based on that experience alone, I would always use a shorter crank. Sticking with a braking
question for one second, and Martijn is looking at a fantastic deal on a rim break bike,
DI2, sounds very nice, but the bike does need
to last a good few years, ideally about five years
by the looks of it. With everyone switching to
discs, he’s a little bit worried that there won’t be any
availability of spares or different wheels in the future. Now Martijn, I really
wouldn’t worry about this. It’s about five years ago
that discs started to be more widespread on the road anyway, and you can still buy
an absolute abundance of spare parts right now. And I really cannot see this changing in the foreseeable future, namely
because there’s going to be so many rims out there,
so many hubs out there, that are currently on the
market that simply won’t be purchased because a lot of people have already gone to discs. Meaning you’ll be able to
find yourself some absolute bargains over the years going forward. And in some markets, discs
just really haven’t taken off at all. Especially in the racing market. It’s quite rare that you
see an entire bunch full of amateur cyclists racing disc. So I don’t think you’re
going to have any problems. Enjoy your bike and make
the most of that deal. Sina Shahidi. Hi John, thanks for the great show. I’ve recently purchased a
Canyon Endurance AL8.0 Disc with Shimano Ultegra 8000 group set. So far, loving it, and so you should be, it’s a lovely bike. However, there’s something
a bit irritating. Most of the time when I
paddle out the saddle, I hear a disc rub noise
that I think is coming from the front wheel. Is this because of flex in the fork? Is there anything I can do to stop it? Could it be because of my
weight as I’m kind of a heavy, heavy rider for the road. Thanks for the help in advance. Well (clears throat), it could be a very slight
misalignment of your caliper and your pads inside your caliper. So, if you want to check
that out straight away, make sure you’ve watched
the video that’s just about to pop on your screen. It could also be that one your
pistons isn’t quite returning back into the caliper
meaning that it’s sitting ever so slightly out, in which case you could use something like a tire lever, which
fortunately I happen to have on the desk here, to prize the calipers back in. Don’t push on the pads,
push on the caliper itself and use something soft like a tire lever. If that doesn’t cure it, then it could be that
your thru-axle is in quite opposite correct torque setting, meaning that there’s a
little bit of play there in the wheel. You could also check your hub
bearings to make sure that they again have no
sideways movement in them, any lateral play. But I would imagine that
it’s probably the alignment of the caliper. George Duffy up with, hi John, I have a carbon
steerer and a carbon stem and I found that when torqued
to the specified level, that my stem can still
slip and I end up with bars pointed to the side. I was trapped standing
at some traffic lights, and I nearly came off
when the light went green and the bars turned sideways. I had a multi tool in my back and tightened the bolts by hand so I was able to finish the ride. But obviously I’m uncomfortable
going over max torques I think on this steerer tube. What do you think about fiber grip on the steerer-stem connection? The internet seems a bit
conflicted on this one. I was also thinking maybe
it’s the bolts coming loose and some thread locker is the answer. Now, George, what I would
do is take the bolts out of the stem completely,
give them a good clean and then grease them up properly. Because it could well be
that any extra resistance that you’re experiencing was tightening those bolts up is causing your torque
wrench to over read. And on that note about your torque wrench, are you sure that your torque
wrench is 100% accurate? And if you are, then the next
step I would use would be to in fact use a little bit of Gripper Paste. Because that is fantastic
things like this. It’ll stop any subtle slipping
no matter what amount of torque you’ve managed to put on to those. So ,it could well work
really well on your bars. I know exactly the issue
you’re experiencing. I did it on a bike. And, I’ll be really honest,
it was a team bike at the time and because I don’t pay for
them I did over torque it a little bit. And it was absolutely fine. Honestly, I didn’t go crazy with it. Just one or two Newton Meters
will have the desired effect. But if you’re paying for your bikes, it’s probably not the best
recommendation, is it? So address all those other issues first, and if intact, take it
to a local bike shop and see what they say as well. Good luck with that. It shouldn’t be too big
an issue to get on top of and hopefully it won’t happen again. Danny up next, right. Danny has a 2017 Cannondale Super Six Evo. The front is a thru-axle but the rear is still a quick-release. He’s currently happy with the wheel set. However, when he does want to upgrade, is it going to be difficult to
find a wheel set that going to align for both the
quick-release and a thru-axle on the same bike. Moreover, being at this wheel set, will he even find a
quick-release rear hub. Can I change the rear hub
to allow for a thru-axle. Well we’ll start at the end first. No, you can’t change the hub because your frame doesn’t
allow for a thru-axle. However, what you can do
is buy different end caps for almost every wheel set out there. And that will allow you
to use either a thru-axle or a quick-release in the same wheel set. So these end caps they are
effectively the last part of your hub before it meets the frame. And they wedge up against
the end of the frame and then they’re clamped in on thru-axle, the thru-axle goes right
through the middle of them and it rests on them on the quick-release. There’s a little bit of
play between the two because your bike doesn’t actually
sit on the quick-release. It’s these things that
you will need to replace on the rear wheel to
allow for a quick-release when you’ve got a thru-axle rear hub. It’s normally easier to
get a thru-axle down to a quick-release than it is to
do it the other way around, because reverse engineering
is often the case with these things. There are many available on the internet and no matter which wheel
set you choose to buy, you shouldn’t find it
too hard to find a set. If you are worried though, before you go to buy the wheel set, make sure you actually check first, that you can indeed use these adapters. That’s it for another
week on the Tech Clinic. If you do have a question
that you would like to be answered, don’t
forget where to drop it, down in the comments below
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