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- Welcome back to another
episode of the GCN Tech Clinic
where I try and solve your
bike-related problems.
So if you've got one,
leave it for me down there in
the comments section below,
or alternatively, on all
forms of social media
using the hashtag #ASKGCNTECH.
And with no further ado, let's crack on
with the first one this week.
Comes in from Sebastian who says, "Hi Jon,
"I'm thinking about
getting oval chainrings,"
The Osymetric ones.
"Is there anything that
I have to be aware of?
"I'm currently running SRAM Red eTap,
and I'm wondering whether I can keep using
my current cranks, etcetera.
All right then, Sebastian,
fancy yourself a little bit
of Chris Froome tech, do you?
Yeah, a couple of things really,
just be aware of with
those Osymetric rings.
They aren't the easiest
things to set up, I must say.
You have to have the front
derailleur absolutely spot on,
and it's pretty high up,
actually, on your seat tube
or on the front derailleur braze-on
just to be able to accommodate
the over-sized chainring size of them
because you tend to go up probably
four or five teeth on them, from memory.
Secondly, when you're actually using them,
you need to use your legs
almost like a clutch mechanism,
so you want to ease off
the gas a little bit
when you change the front derailleur
to allow the chain to find its
way onto the other chainring.
They don't tend to work quite as perfectly
as, you know, factory-fitted components
because they've got
shifting ramps and pins
and they've really been
designed for one another
and to work with those
specific chainrings.
They do work, obviously.
Tour de France is have been one on them,
but I have spoke to
Tour de France mechanics
and even they've said,
"They can be a little
bit for a pain them."
And yeah, like you say,
they will work absolutely fine
with your SRAM crack arms.
The reason being, the actual chainrings
are really quite cut away,
so the kind of mounting tabs,
they come away, there's
no filled in chainring
that's here or anything like that,
it's quite minimalistic.
All right, next up, Luke Benton,
who says, "I'm getting a new saddle.
"Using my bike to commute,
"anyway I can secure it when I lock it up?
"Or am I going to be taking the seat post
"with me on my shift?"
Right, Luke, good thinking.
You don't want to go
lugging around a seatpost
and saddle with you, do you?
So instead, get yourself a cable lock
and just loop it through
the actual saddle rails
and then join it onto either
the frame or some railings,
something like that, of course,
not forgetting to actually
lock up the bike itself.
Ultimately, though, and this
is really, really sad news,
isn't it in this day and age
that if someone really wants
something, they will take it.
But, unless it's a very,
very expensive saddle,
I'm guessing they're just going to pass by
and not bother taking it.
So just make sure you're lock it on them,
just a little cable lock.
All right, next up, we've
got a question from Bugboy.
I think Bugboy has put
some questions in before.
Either way, we'll answer this one too.
"Hello, love the show.
"I'm on a Canyon Aeroad
"that didn't come with integrated bars.
"Currently running a
pair of Zipp carbon bars.
"I've also recently had
a bike fit performance
"to which they flipped my
stem to a plus six position.
"Any recommendations on carbon stems
"and/or carbon bars
"that fits one inch
and a quarter steerer?"
Right then, Bugboy.
There are a few different
options for you there.
You've got Vision, Ritchey, and Giant.
That's just off the top of my head there.
But the Giant, from memory,
only comes in an eight degrees,
where as the other two are
in a six degree angles,
that would be fine for you.
Something, though, really
to consider with this,
they are pretty expensive.
You're looking probably
about 250 pounds, 250 euros,
300 dollars, something like
that, upwards for those.
So just have a little shop around,
and maybe you'll be able to find yourself
a little bit of a deal there too.
Now we have Han-Soo Cho who
says, "I'm fairly to cycling.
"I've just bought some
700c by 28 milimeter tyres.
"For the inner tubes, is it
better to get an inner tube
"where the maximum width 28 millimeters,
"or where there minimum
width is 28 millimeters,
"or are either fine?"
All right, then.
Both of these will be
absolutely fine for you
because rubber is nice and stretchy.
The wider ones, to start
with, so the 28 mil upwards,
they're going to be a
little bit more difficult
to get inside of the tires.
So it could well be a struggle
depending on what type of rim you're using
and also with tire and how
they match up with one another.
But, the other side, so the thinner ones,
well they're going to
work absolutely fine too
'cause rubber, like I
said, nice and stretchy,
so it will work,
and you're going to save
a bit of weight there too.
But if you want to find
an even better solution,
maybe 25 to 28, they're
going to be almost spot on
for those 28 mil tires.
Next up is Dennis who says, "Hi, Jon.
"Can you also put tubeless sealant
"in an inner tube to seal
the small punctures?"
Yeah, you can.
Now the easiest way to do
this is with a Presta valve,
so one that you can remove,
importantly, the valve core
because that's going to way easier
to pour that fluid in there.
I've done it in the past on my own bikes,
and it worked, luckily,
because I actually forgot
my spares that day.
I don't know what I was thinking.
Another time, I punctured
and it didn't work,
but, luckily, I had my spares there too.
Always does depend on the
actual size of the whole
which you've got there and
what's gone through the tire
and into the inner tubes.
Always do take some spares with you too
just as a secondary measure.
Right, next up in Vercin who says,
"Can you solve spongy caliper brakes?"
Right, well, hard to know exactly what's
going on here, Verci.
You've not given me the most information,
but, importantly, first of all,
makes sure that the actual
break pads are touching
both sides of the rim at the same time
so you're getting equal power there
and one's not biting and the other one is
slowly coming onboard.
And then, if you've towed in your brakes,
makes sure you've not
towed them in too much.
I mean, obviously, this
is a large exaggeration.
But you want to make sure that
the front part of the brake pad
is just a fraction
closer than the rear part
when you're actually
touch them onto the rim.
So it's going to be a millimeter
or even less a lot of the time there.
Another thing to consider here
is the actually brake cables
and housing, make sure that they're nice
and in good condition too.
A new set of brake cables
doesn't cost an arm and a leg,
and importantly, quite often
can make the difference
between a very poorly performing brake
and a really good performing one.
Make sure you use ferrules where needed
and good quality pair
of cable cutters too.
Next up is Gabriel
who's a GCN fan all the
way from the Philippines
and is new to carbon rims.
Want's to know, "Can I use
alloy break pads in carbon rims?
"What are the differences?"
Right, no in a word.
The reason being, those two
different types of brake pads,
alloy and carbon have different
levels of heat resistance.
So an alloyed one is much
lower than carbon one.
And in turn, it means that the alloyed pad
is generally quite a bit
harder in it's compound,
and when you try and
brake onto a carbon rim,
just doesn't give you the
same braking performance
'cause it's too tough against the rim,
and ultimately, it's
going to start wearing out
your carbon brakes surface,
which is going to be,
not only dangerous, but also costly
in the long run there too.
Another reason is that
many people out there,
they just swap between
carbon and alloy wheels
and leave the same brake pads in.
That also is a big no-no, the
reason being, when you brake,
quite often your brake pads
pick up tiny, tiny fragments
of aluminum, or alloy,
from the braking surface,
and from the road,
and they tend to embed
into the brake pads,
and that too can score rims
and render them useless.
For the low cost of specific brake pads,
I always recommend the use of them.
Final question this week
comes in from Andy Turner.
I once knew an Andy Turner.
Maybe it's you.
Right, either way, "Hi,
Jon, great show as always."
"I have a question,
"I have built up my new
Trek Madone nine frame set.
"The hardest bit of the
build was routing the cables
"through the integrated handle bars."
How many times have I
heard this about bikes?
"Something I was keen not to
have to do again anytime soon,
"but on the first test ride,
it rides like a dream,"
That's great.
"expect the cable rattling
inside the handlebars."
That is not great.
"Please help and suggest ideas
"other than expanding foam
would be greatly appreciated."
Right, yeah.
Do not put expanding foam
inside of you're handle bars.
It makes a hell of a mess, and,
well, it's not difficult to,
well, it's not easy to
get rid, should I say.
Right, easiest thing for you to do here,
get some bubble wrap, so
the sort of thing which you,
I don't know, comes in with
your mail order, whatever.
Just little bits of pockets
of air inside of some plastic.
Don't throw it away, cut
it up into small bits,
wedge it into the handlebars,
and then use, get this, an old coat hanger
and try to bend it bend it into place.
Try and get it so it goes
in between the outer brake cable housing
and the inside of the carbon bar
creating a kind of bed if you'd like
so it can't go, bru, rattle, and click,
and all that because those
noises are the worst.
If I have a noise on a bike,
I simply won't go out
and riding it until I try
and find out and solve that problem.
That will get rid of it.
You don't need to use expanding foam.
Keep that for your PVC,
doorframes and window frames.
Right, Andy Turner, hope
I've been able to help answer
and solve your problem.
Let know how you've got on
with that bit of advice.
Now remember as well,
like I said at the start,
if you got a problem,
leave it for me down there
in the comments section.
I love, love, love reading through them
and trying to solve them.
Remember as well to like
and share this video
with your friends.
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