- So this week is a very special edition
of the GCN Tech Clinic because, what can I say,
I'm on location here at the Dubai Tour.
Now I don't have my toolkit with me,
so I can go too in-depth,
but I still reckon I can tackle your questions.
Let's see.
(ambient music)
First up this week is a question from Sophie,
who's got a braking problem.
Yep, nobody likes braking problems
because, well, they help you stop.
So, the problem is that they're pulling the lever,
and despite re-greasing the cable, replacing the cable,
it's still not working well.
So the first thing I would check is make sure,
if you've ferrules on the end of your outer cable,
is make sure they're fully pressed all the way on.
But also, importantly, is that the end of the outer cable,
before you put the ferrule on,
is to actually make sure it's a very clean cut, very flat,
then put that ferrule on fully, all the way.
That way, you're not gonna get any slight movement
of the ferrule on the end of the brake cable.
So making sure there's no gap on the end,
and you're not braking, effectively, in the air,
if that makes any sense.
So make sure of that.
Another thing to also check is to make sure
that the callipers and levers actually match up.
So Shimano and Shimano, SRAM and SRAM,
Campagnolo and Campagnolo.
Reason being, they actually have
a different lever pull ratio to the brake.
So that's really important to remember.
Right, now next question is from Mark,
who wants to know when to replace a tyre.
Mm, well, like you say, obviously if there's
any nicks or cuts in the tyre,
then sometimes it's time for a new tyre.
Then other times, you can actually
just fill those holes in with super glue,
just to actually try and prolong the life of the tyre.
Now as for indicators, to let you know when
to replace the tyre, actually Continental,
who do supply us with tyres here at GCN,
they have two little indicator holes on top of the tyre.
Now, they're not obviously holes all the way through.
Those holes, they go just a couple of mil
beneath the surface of the rubber.
And essentially, once you can't see those holes anymore,
you know it's time to replace the tyre.
So that's one brand in particular
who are doing something about that.
Another thing to keep an eye on,
make sure the tyre still has a
rounded profile across the top.
Once it goes flat, basically, the tire's not gonna do its
job properly when you're going around a corner.
So just keep an eye on those things,
and you'll be good to go.
Next up is lonewolf, even giving me a name check.
Thank you very much.
Problem with a rim flexing against the brake pads
when they get out of the saddle for the first few strokes.
Now if your wheel is in straight,
actually check the spoke tension
because there could be some flex in there
that when you're putting a bit of weight
through the front end of the bike,
that rim is just moving over and touching the brake pads.
Also, maybe you've just got your brakes set
very, very close to the rim.
So naturally, you're gonna get that bit of movement.
Okay, so Stuart wants to know, how long do gear cables last?
It's a great question because I honestly don't know.
But do take care of them, so when you're washing the bike,
make sure you don't use any harsh degreasers
that are gonna get in there and wash out
any grease from the cables.
Obviously, use as well, once you're finished
washing the bike, a good water-displacing spray,
so that you're removing any of the water from inside,
and then preventing any rust of the inner
and also the inside of the outer cable too.
Keep a good eye as well to make sure that the cables
aren't frayed where they're clamped into the derailleurs.
Obviously, on this bike here, I've got electronic gears,
so I can't show you that exactly.
But also inspect the outer cable too.
So where there's any sharp bends
or where the ends are a ferrule, make sure that there,
the outer cable casing is not cracking at all.
But who knows?
They could last up to two or three years,
I guess, maybe longer, maybe less.
It all depends on the riding conditions.
Right, Christian wants to know, does vinegar help
grip on tyres or reduce the chance of punctures?
That is a brilliant question, 'cause you know what?
I actually know the answer to this, or kind of.
Firstly, I'm gonna let you know,
it's not the vinegar that you put on your fish and chips.
It's actually white vinegar, and I've seen this done
by the Great Britain mechanics inside of a velodrome.
They actually did it using a Dugast tubular tyre,
and that was one of the pink ones, which from memory,
it's quite a while ago now, is a latex-treaded tyre.
So essentially, they got that white vinegar,
coated a sponge in it, then went around the tyre,
and then the riders went out and rode.
Did it improve the grip?
I don't know, but there must be some logic behind it
because they were brand new tyres.
And sometimes brand new tyres
on a velodrome are quite slippy.
Whether or not they reduce the chance of punctures,
can't tell you, I'm afraid,
because inside of velodrome, it's pretty rare
we actually see anyone get a puncture.
But try it, and let me know how you get on.
Next up is this question from Hitesh,
who wants to know, how often should you
replace a bike helmet, and does foam degrade?
This is a great question, actually,
because I used to work for a helmet brand and manufacturer,
so I've got a little bit of inside knowledge.
However, most helmet brands, in fact, none of them
give a definite answer when you should replace it.
Obviously, the outer shell, so that polycarbonate shell,
can get damaged by UV rays, especially
if you're somewhere like this in Dubai.
Obviously, in the UK, we don't get that much sun.
We get a little bit.
But, yeah, it can degrade the foam
and the polycarbonate shell,
But what's also important to remember,
if you do drop your helmet, even from a very small height
or very gently, it can still damage that helmet,
and essentially render it useless because you may well
have some tiny, little hairline cracks in amongst the foam.
But basically, the helmet has done its job,
even if you weren't wearing it at the time.
(man whistles) (upbeat music)
(moves into tense music)
- No!
- Also, take care and try and keep the helmet clean.
I actually give mine a good old scrub in the shower.
I use some shower gel just to clean it off,
and I don't use any harsh chemicals at all
because you don't know what that's gonna do with the foam.
It may well react to it.
Also, remember those pads too.
Take them out, and give 'em a good clean
with some shower gel.
Rinse 'em out thoroughly because afterward,
if you start sweating, you don't want some soap
to come down into your eyes.
Final question this week is from Dan,
who is thinking about changing to tubeless tyres.
But what are the pros and cons?
Well, let's tackle the pros, first of all.
Obviously, there's gonna be less rolling resistance
'cause you're removing the inner tube,
and then, essentially, you're reducing that friction
in between a tube and a tyre.
Although it's not a lot, there is still some there.
Also, you're gonna do away with a high-risk
of pinch punctures because there's
no tube in there to pinch.
You can also run the tyres at a lower pressure too,
which is quite a trendy thing
or even scientifically proven to be a little bit faster.
And finally, one of my favourite pros about it,
is that you can put some sealant in there,
when you've set them up, and essentially, if
you get a bit of thorn or glass in the tyre,
once that's out, the sealant does its job
and seals that hole, so you can continue riding,
which, for someone who doesn't like to stop
at the side of road and change inner tubes,
that is pretty important.
Now the only cons really for me is
actually the tyre choice and the tyre availability.
At the moment, there's not a huge range out there,
so if you're particularly fussy
about your tyres and treads and brands,
then maybe it's not the thing for you.
But I'm sure that as we see tubeless tyres continue
to develop and evolve, we'll see more brands
manufacturing and releasing different types of tyres.
Right, I hope you've enjoyed that,
and I've helped fix your bicycles.
Remember as well to leave your tech problems
for me down there in the comments.
I love reading them, and most importantly,
I love getting you back out on your bike.
There's no excuse because Jonny Tech is here.
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