- Welcome to another GCN Tech Clinic,
this week I answer your questions
on persistent punctures through axles
and rebuilding wheels.
Don't forget, if you want to have
your question answered here on the channel,
drop it in the comments box below and use
the hashtag ASKGCNTECH, and in fact,
you can throw that onto any of our social media platforms.
Right, first question is from Manas Deshpande.
He has a Cannondale CAAD12 with 105,
with a fulcrum racing sport wheel and hub.
He wants to buy a PowerTap G3 hub,
and build it into his current wheels.
He wants to know, is this possible?
Well, yes, assuming the hub and the rim
have the same amount of holes, imagine they're 24,
then yeah, you could go and do that
and get your local shop or mechanic to build it up for you,
but, I would actually recommend going out
and sourcing a brand new rim, or the spokes
and the nipples for it as well,
because then you'll have a completely
bespoke custom-built wheel
that was designed specifically for that PowerTap.
The other reason for doing this,
is inevitably, during the lifespan of a power metre,
it will need to be sent off for a service
or some sort of maintenance work,
and if you don't have a spare wheel,
then you'll be stuck without a bike to ride
for however long that takes, could be a week,
or it could be up to a month depending
on which manufacturer or service centre you send it to,
so, having that spare wheel will always be invaluable.
If you have spare wheels already, I still recommend
actually going out and buying a new rim,
because I just think it's better
to have something that was purpose-built.
Good luck, and enjoy your new wheel.
Paul Hatcher writes in with, "I have recently acquired
"a frame with 12 mil through axles.
"Why are through axles using a right hand thread?
"Wouldn't a left hand thread be safer,
"as should the through axle become loose,
"the rotation of the wheel would likely
"be to tighten the through axle rather than loosen it?"
Well, Paul, I think that's a really good question,
certainly as we move forward into this new era
of bikes, which are predominantly
gonna be coming with through axles.
However, take your through axle,
stick it through the hub of your rear wheel,
and spin the wheel, and you'll notice,
that assuming your bearings are in good condition,
there isn't actually all that much drag on the axle.
That coupled with the fact that you actually
need to do them up reasonably tight
in the frame means that there is really
very little risk of them ever coming undone,
thus negating the need and complication
for a left hand threaded axle.
Richard Isaksen is asking, "I've recently been wondering
"how often I should be cleaning and lubricating
"my chain whilst I've got my bike set up
"on the indoor trainer.
"Its obviously not gathering much gunk,
"but I'd still like to know,
"should I be applying lube frequently?"
Well the question is, what are the conditions like
where you're using your bike, is it quite a damp area,
or are you using air conditioning, or big fans,
which are perhaps drying out your chain?
I think the best way to go with this one
is to play it by ear, have a little feel
of your chain before you use it,
and then listen out to the noises
it's making as you're warming up.
If it sounds a little bit dry,
or it isn't sounding sweet and smooth like it should be,
then add a little bit of lube in between
all of the rollers, and this will help
keep it in top condition for you.
John Mac up next, "Hi guys, quick question.
"Is there a way to repair cuts to tyres?
"My commuter's front tyre has a decent nick in it,
"and I'm worried something else sharp may
"find its way in and give me a puncture.
"The tyre has loads of life left in it,
"so I want to save it, I've tried super glue
"and gorilla glue, but they both come out
"over the course of a ride."
Well John, there's no need to worry,
because there are a few tricks you can use,
and the first thing I would start with
would be trying a tyre boot,
a purpose-made sliver of rubber
that was designed for patching holes in tyres.
Stick this on with some vulcanizing glue,
that's if it's not self-adhesive.
Vulcanizing glue works because it has
elasticity built into it, and it will expand
as you pump up your tyres, and as they deflate.
If that doesn't work, though, you could try
a piece of an old inner tube, I'd probably
double it over, and then stick that in place again
with the same glue as I mentioned before.
If that's not good enough, then try a piece
of an old tyre, so cut out a thin part of the old tyre,
maybe where the centre tread was, where you've
ridden it the most, and insert that up into the tyre,
and glue that in place as well.
Remember, though, when you do this,
to leave a good overlap so that
you're covering the hole completely
as the tyre is more likely to expand,
that split is likely to grow over time,
so make sure you give yourself a good bit of coverage.
Henry H is up next, with a question about through axles.
"I have three different bikes with through axles,
"and all of them have different size rear wheel axles.
"Is it possible to convert the axles so I can use
"the wheels on different bikes, or are the wheels
"going to be bike-specific?"
Well that's a brilliant question,
because as we mentioned before, through axles
are becoming more and more prevalent
across more and more bikes.
And the answer is yes, there are adapters available,
but not every combination is gonna be out there,
so for example you might have a 135 millimetre
rear wheel, and you wanna put that
into a 142 millimetre frame.
That will be possible with an axle spacer
or a new end cap on your hub.
But, if you have a 142 hub, and you wanna squeeze that
into a 135 frame, that might be difficult
and you may find that it's
not gonna work for your combination.
So, with a bit of Googling, and a bit of time
invested online, you should be able to find
what combinations you have,
however, at the end of the day, you may also find
that only two of your three wheels fit in the other bikes.
Good luck, and let us know how you get on.
Next up is Keyller Gonzalez, who is having
problems with punctures, riding their 1982 Benotto
they're having one puncture a week,
pretty much, on the back wheel.
Now, they've checked the tyres,
they've checked the rims, the brakes,
and they haven't found a reason for it happening,
they keep their pressures controlled at 90 to 100 psi,
and they weigh around 100 kilos.
Is there something they're missing?
Well, the first place I would check is your rim.
So, you say you've checked the rim and the tyre,
but what I mean is check the rim tape,
so if it's that hard, plasticky rim tape,
really have a good dig down where the nipples are,
because you may be missing a few cracks,
which could be snagging your tube.
If that doesn't work, then I would try
adding an extra 10 psi to the tyre pressures,
because with 100 kilos on top of the tyres,
an extra 10 psi could really
make a small difference for you.
If that doesn't work out, then the next consideration
is to replace the tyre, because once a tyre has punctured,
and you've run it even briefly flat for a few metres,
then it's kind of weakened the outer structure
of that tyre, and you will find
that is gonna be more susceptible to punctures.
But, if you don't want to replace your tyre,
or you can't replace your tyre,
then picking up a protective rim strip
is a good next port of call.
You can pick these up really cheap,
just for a few dollars, and they can be
really quite effective in keeping any
small sharp objects out of your tyre.
And then the next fail-safe I would recommend
is actually filling your inner tube
with some sealant, not filling up,
but around 50 to 60 millilitres of sealant
can be really quite effective.
It won't be quite as good as a true tuber setup,
but it will still work really quite well.
Good luck with that!
Paul Ferguson up next, with "Can I get some tips
"on how the Shimano trim function works?
"I have a new bike that's only done around 60 kilometres,
"and I'm getting a bit of chain rub on the front derailleur
"when in the large ring and the smaller rear cogs.
"I keep reading about trim, but just want
"to understand how it actually works, thank you."
Well, Paul, trim is actually as you shift
the front derailleur across,
you can use it in stages, there's a ratchet mechanism
inside of the shifters, and to trim
would be to go one click or two clicks or three clicks,
as opposed to just all the way up onto the big ring.
I think the question you might be asking, though,
is how to actually adjust your front mech a little,
because, as you have a new bike,
now that things have settled in, the barrel ends
have gone onto the outer cables,
and any excess plait in the new cables has gone,
and they've stretched that little tiny bit,
it's all very precision work, so you're gonna want
to take up any slack, and what you want to use
is the barrel adjusters, and these will either be
in the cable somewhere on the outer cable,
or on the down tube or something like that,
and what you want to do, as you're stood over the bike,
is just give them a few short turns
anticlockwise, probably not even a full turn to be honest,
and this would just take up a little bit of slack
that you might be finding in your cable,
meaning that when you're on the big ring,
and further down the block,
you're no longer getting that rubbing.
Gulf City Nicholas Danca, "I want to swap my rear mech
"out to a Shimano Deore one without changing the gearing.
"It's an eight speed block, will it work?"
Well, yes, simply, as it's a Shimano part,
there is no foreseeable reason why
the rear mech won't just do what the
front shifter is telling it to do.
They're indexed to the cassette, not to the rear mech,
so you should have no problems whatsoever.
The penultimate question comes in from Lod Vaessin.
"Hi guys, this coming July I'm going to France,
"riding my bike in the mountains.
"I'm considering using my full carbon wheels
"because they're light, I also have some
"mavic carbon wheels with an aluminium braking surface,
"and I have a set of full alloy fulcrum wheels."
Which set should he take to France,
because of the heat buildup during a long descent?
"I'm a good descender, but I'm not a pro."
Well, Lod, I would honestly take
the set of wheels that you think you're gonna
enjoy riding on the most.
If it's your lightweight carbon wheels
riding up the mountains, then I would absolutely
encourage you to take those.
I would have no concerns about them overcooking,
as it were, on the descent, because
you're not going to be racing the cars down the mountains,
you really shouldn't be, anyway.
And the heat built up on the entry
into the corner will soon be gone
by the time you're halfway down the next street.
If you're worried about the weather,
and you want to have a better braking surface
in wet weather, for example,
then I would take the aluminium wheels,
but yeah, it comes back to taking the set of wheels
that you're gonna enjoy riding the most.
JH Janson with the final question of the week.
A few days ago, on his first ride outside this year,
he experienced a chain snap whilst
accelerating out of the corner.
Managed not to crash, luckily.
The chain was a 105 chain and still in good condition,
but it snapped on the plates.
He's heard this is quite unusual, what is our opinion?
Well, yeah, this really is quite rare.
In the past, you maybe had the joining pins
that would snap, and it wasn't that unheard of
for a chain to snap, but these days
they're much more sturdy than they used to be,
and it in fact is really quite rare
for a chain to snap, you also maybe heard
of manufacture defaults in the past,
in chain recools and things like that,
but after a good search online,
we cannot find any evidence of those happening anymore.
So, it comes down to installation and maintenance,
but, as you said the chain was in good condition,
I find it hard to believe either of these are the cause.
So, you're left with a freak incident.
Luckily, it's a very rare thing to happen,
and you're unlikely to experience it again.
That's it for this week, so if you want to get
your question answered on the GCN Tech Clinic,
make sure you use the hashtag ASKGCNTECH,
and you can leave that on any of our social media platforms.
For another tech-related video,
why not check this one out over here?