– 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?