(dramatic music)
- Welcome back to another episode of the GCN Tech Clinic,
where you submit you bike-related technical problems
down there in the comments section.
I'll do my very best to help solve them so you can get,
well, riding your bike again.
So, if you got one, let me know all about it.
And as ever, let's crack on with
the first question this week.
That comes in from Leonard, that has a Diamondback,
and every time they take a large turn,
the front wheel contacts the front of the foot.
Now, they use cycling shoes as well,
but what could be the problem?
Right Leonard, I don't know what size bike you're riding,
but this is a problem which tends to affect riders
using a smaller-sized frame than anyone else.
But, it can happen.
In fact, everybody out there,
if you're turning a larger radius with your handlebars,
which is not something we do that commonly,
so you don't tend to really ride like this.
You tend to just lean when you're cornering a lot, and yeah.
I reckon on my own bike,
if I was to try and do a 180 very slowly,
I would probably end up actually
touching the tire with the front of my cycling shoe.
But also, something to consider here,
it doesn't actually happen that much
when you're riding along.
If it's only when you're doing one of the big old turns,
don't worry about it too much; just actually be aware of it.
And also something to be aware of is
how far forward or back your cleats are on your shoe.
So if they're quite far back on the sole,
that's gonna give you a bigger toe overlap
than if they were in the center or, you know,
central of the mounting bolts or really far forward on them.
So, just think about that as well.
Hopefully though, you're not going to be plagued
with that problem when you're actually riding along.
And our next one is from yurimow,
who says, "Hi Jon, another rim brake conversion question.
I'm restoring an old Bottecchia and I'm considering
converting from cantilevers to side-pull.
The holes in the frame are present,
but I'm worried they might be meant just for mudguards,
and not be able to handle the stresses of a brake."
Whoa, a Bottecchia, or Bottecchia.
Absolutely brilliant bike.
Fond memories of Greg LeMond, 1989.
Yeah, he used one of those.
Anyway, what about this problem then?
Well, first up, it's very unlikely that that frame
is going to be compatible with both, I think.
I mean, I haven't actually seen
that module you're talking about,
but there's not many bikes out there
which were designed to take both cantilevers as well as
a standard brake on there.
So, personally, I wouldn't risk it.
I haven't seen the holes, but taking it into a,
like a shop maybe, they'd be able to advise you.
But, why not restore it to its original glory
of having cantilevers on there?
And when you've done with that,
send in a picture of it to me for the GCN Tech Show,
so we can actually use it in the bifolds,
cause it's gonna be a beauty there; an old Bottecchia.
But yeah, personally,
I wouldn't risk it if you're totally unsure.
Go and use those cantilevers.
Go on.
Now, next up is Dylan Kite.
Now, Dylan says, "I've got a question relating
to tire width versus rolling resistance."
Dylan understands that wider tires have
a lower rolling resistance, but they weigh more,
so where is the crossover point for where
the higher weight outweighs the benefits of
the lower rolling resistance?
All right, Dylan.
These questions are a can of worms.
I'm just gonna put that out there,
because, well, we're all riding
in different styles, different road surfaces,
different tire pressures, different tires.
So, there's no definite answer
for everyone out there, but don't worry.
I did in fact reach out to a wheel company
to ask about whether aerodynamic differences
actually make a real change when it comes to tire width.
And they reckon, once you go above 28 millimeters,
that's where the positives of using a wider tire,
so generally a better rolling resistance and also
you can, kind of, ride with ease over poorly-surfaced roads,
that kind of thing if that makes sense,
once you're above 28 millimeters,
they start to become less efficient.
So, less aerodynamic, increased weight, those things.
So, the positives start to turn negative,
so I hope that's a bit of an indication.
And I know that someone in the comments
is going to be giving me absolute grief over this.
But like I say, there is no one answer suits all,
cause it does depend again, what size tire you're using and,
well, all the other variables I've already mentioned.
Next up is Ali Yazdi.
Now Ali says they've got a cheap wheel
that they only use on a trainer,
and if they want to service it,
should they use grease for ball bearings
or can they use a thinner lubricant,
as it lowers the resistance.
Right.
Thanks for the message.
Use normal grease.
Yep, I know that thinner grease could lower the resistance,
but you're on a trainer; therefore, you're training.
And really, if anything,
you want to have the hardest ride possible,
but without actually damaging any components or suchlike.
So, go ahead.
Use that normal grease.
Okay, next up is Ivalio, who says they've got a problem
with their front inner trigger on their gear levers,
so when they shift to the big ring,
the inner trigger sometimes does not return
to the original position, but instead,
remains kind of stuck out there.
They have to give it a little bit of help and it goes back.
It's not a big deal, but they want it to be right.
Right then, Ivalio.
What I would do is have a look at that inner lever,
and the little bit of plastic on it, it tends
to be attached to a thin bit of metal on the inside,
just behind the main break levers.
So, I make sure it's not become bent or twisted at all,
because when we're gear onto the big chain ring,
we tend to use a little bit more force,
and it's quite often actually,
you can use a different motion from the other hand
because of using a little bit of additional force.
And in turn, that can bend that bit of metal plating,
which the lever is essentially attached onto.
And in turn, that can just become slightly out of line,
and then not pop back into place.
It is an issue which plagued me on
the old Shimano Deore A-17900 shifters,
and I had exactly the same.
For some reason, my left hand,
it tends to just slightly warp it,
and yeah, I used to have to do the same.
Just gently bend it back and it
should spring back into place, A-OK.
Right, next up we have Hutchinson,
who says, "Hi Jon. Is it okay to clean your bike components
in a stainless steel kitchen sink
if using bio-degreasers and washing liquids?
I promise I won't tell the missus."
Hutchinson, love this question.
The kitchen sink: absolutely fine.
But, be aware though,
actually where that wastewater is actually going,
because yeah, you may well be using bio-degreasers,
but if you're washing oil from a bike,
where's that going to end up?
If it goes down the kitchen sink,
is it going to end up in the local water source
or something like that?
So actually, just think about that.
Personally, I wouldn't bother doing it.
Plus also, you run the risk of being caught, don't you?
I know you're not going to tell your missus, as you say,
but what if you get caught?
Naughty.
So, I wouldn't bother doing it.
And next up is Cristian.
And now, Cristian says they've just bought
their first road bike.
It's a mid-90s Ribble 653 steel frame
with the original two by eight Campagnolo Athena groupset.
Wow, I remember that.
Those Ribbles were so popular back then.
And also, that Campagnolo Athena
from back then was absolutely beautiful;
polished, engraved logos, all that.
Anyway, right, what about the question?
Now, if they were to change the brakes to dual pivots,
would they have to replace the levers?
And also, what am I better off upgrading next
to more modern components: the wheelset or the drivetrain?
Right, brake levers.
What we've got to think about here is if you're going
to be putting on a new set of brake calipers,
is that the cable pull ratio is likely
to have changed over the years,
so in order to get the best possible braking,
you are gonna need to put some
new brake levers on there too.
As for the best thing to upgrade,
don't take off that drivetrain.
Please, don't.
It's absolutely fantastic.
It's one of my favorite eras of Campagnolo,
so please, please, please just don't do that.
Instead, get yourself some nice, classic-looking
wheels on there instead because normally,
the wheels are what make the big difference
on a bike when you hop on it.
Yeah, keep those downtube shifters too.
It's an absolute classic, that.
Can't get enough of it.
And then, send in a picture to me as well.
Right, and the final question this week
comes in from durgimstingetium.
I hope I've pronounced that correctly.
"Hi Jon, I'm using a Tiagra 4700 long cage rear
on the back of my bike with an
11-34 cassette and a 52-36 crankset.
Can I change my sprocket into 12-28?
Do I need to change the rear derailleur into a short cage?
Do I also need to change the chain?"
Right, yep.
You can use that rear derailleur on
the 28-tooth cassette, no problem at all.
Something also worth considering here is that now,
you've actually got slightly more chain-fitted
than you necessarily need, so you could, in fact,
remove a pair of links if possible to.
So, therefore, if you've got a spare joining pin
on the chain or a master link, for instance,
that's a really simple thing to do.
Yeah, in turn, by doing that,
you're actually going to have a more tension setup there,
because you're going to be getting rid of
just that extra little bit of slack in the chain.
Go ahead and do it.
It's a nice, easy thing to do.
Right, there we are.
Another GCN Tech Clinic done and dusted,
but like I said at the start of the show,
if you've got a bike-related problem,
leave it down there in the comments section
because I want to help solve it.
Don't forget too to like and share this video
with friends, and also, check out
the GCN shop at shop.globalcyclingnetwork.com.
And now, for another absolutely amazing video,
click just down here.