- All right, welcome back to another episode
of the GCN Tech Clinic,
where I try and solve your bike related problems.
So if you've got something which is plaguing you,
and you can't go out on your bike,
make sure you leave me that question
down there in the Comments section below,
or alternatively on all forms of social media,
using the #ASKGCNTECH.
And with no further ado let's crack on,
with the first question this week,
and it comes in from Yo Brobeans.
All right, now they say, "I like the idea
"of the 10 tooth sprocket to increase the range
"of gears at both ends.
"However, I can't afforcd SRAM's eTAP AXS groupsets
"as the wireless technology makes them too expensive for me.
"Would the crankset, chain, and cassette be compatible
"with any other components from different groups?"
So, could they take the gearing
from SRAM's mountain bike range,
and use it with a different groupset?
"If so, any suggestions?
"Preferably mechanical gearing with hydraulic disc brakes."
Whoa, right, you're not asking too much there,
are you, Yo Brobeans?
Um, yeah, I guess you could actually make that work.
I'm not sure that the mountain bike components
could well work across with the road ones,
because they tend to have different pull ratios
on the cables and everything,
because that's what you're going through there.
And obviously you want to use mechanical gearing
with hydraulic disc brakes,
so importantly, you need to make sure
that you've got a rear hub which is compatible
with that cassette which has
that 10 tooth sprocket on there,
so you are going to need an XDR driver compatible freehub,
and I reckon probably the easiest thing
for you to go with here,
is the Campagnolo hydraulic cable operated derailleurs,
but obviously with hydraulic disc brakes.
That's probably the thing which could well work,
but I've not tried around with it,
but certainly something for you
to have to think about a little bit more,
because it's quite a complex situation
you could well get yourself into.
Next up is Avin Jansen.
Now they say, "Please help.
"I love putting on bar tape,
"and I've got it down to like a pro mechanic.
"And I've just got a new bike with Di2,
"and the Di2 junction box and the controller,
"what you set it up with is at the end of the handlebar.
"How do I do my bar tape,
"because it's got a cover that wraps
"around the end of the handlebar.
"Please help, a video would be great."
Right Avin, no video needed for this one, my friend.
As you've said, that Di2 junction box
that goes on the end of the handlebar
does have a plastic cover
which just slots over the outer circumference of the bar.
What you're going to need to do with your bar tape,
is essentially get it as far to the end as possible,
almost butting up against that sort of plastic housing,
and just wrap that tape as hard as you can
without actually snapping,
or risk breaking or tearing the handlebar tape.
I agree, it's probably not as good
as the original style of how you're going to fit bar tape,
where you just have a little bit of overlap,
and whack it in with a bung there,
but certainly this is what all the pro mechanics
out there do.
Next up is Colin Jones.
Now Colin says, "Hi Jon, I do a lot of work
"on friends bikes, which are all internally routed cabling.
"I've managed to get a few lengths of tubing
"from my local bike shop that are taken off
"of new bikes that they build from the box.
"This makes the job so much easier,
"so I would like to buy a decent length of it,
"but I have no way of knowing what size, diameter,
"to look for."
Right, go for something with at least an internal diameter
of two millimeters.
That way you can use it for both gears
as well as brakes, because of course an internal gear cable
is a lot thinner, well I say a lot thinner,
but it is a fraction of a millimeter thinner
than a brake cable inner is,
so go for something like two millimeters,
because the thickest internal brake cable you're going to get
is probably about 1.6 millimeters.
So two millimeter internal measurement.
It's going to give you enough room to chuck that cable in.
And importantly, don't loan out this bit
of internal tubing to anyone,
because people have a habit of not returning things.
And next up, we've got a question in
from 1000 Subscribers with no videos challenge.
That is such a weird user name.
Right, anyway.
Now they ask, "Hey Jon, I'm a junior racer,
"and I need seven meters, or slightly below,
"rollout for events."
So, if anyone doesn't know about this,
when you are riding in youth categories,
and junior categories, you can't use a humongous gear
during competition.
The reason being is that generally your body,
and your bones haven't fully developed,
and you could risk some extra stress on it,
so that's why exactly they have these rules in place.
Anyway, back to that question.
"At the moment, I have a 14 to 28 cassette,
"and 50/34 chainrings.
"I've calculated that I need a 52 tooth chainring
"to get the right rollout,
"however I'm asking whether I can still keep
"my 34 tooth small ring?
"Can my Ultegra 6700 front derailleur handle
"an 18 tooth gap between my chainrings,
"or will I have to get a 36 tooth chainring as well?
"Thanks, Flynn."
Right, a 34 tooth chainring,
if you pair that up with a 52 outer ring,
and unfortunately your front derailleur
is not going to be able to handle that very effectively,
meaning that probably, I don't know,
three or four of your harder gears in your small ring,
so if you're in the small chainring,
and the smallest sprocket in the rear,
the chain is going to drag over that front derailleur cage
at it's lowest pass.
It's going to create so much noise.
Really the gear shifting
is going to be absolutely terrible too,
so the best thing you can do though,
is actually get a 36 tooth chainring,
as well as a 52.
Have a look around though,
because you don't necessarily have to go
for the exact ones what you've got on there at the moment.
You could look for an aftermarket alternative,
which is going to serve you just as good.
Next up is mikeylp03.
Right, there we are.
"Hi Jon, love the show.
"I'm restoring an old Trek 1000,
"and I would like to convert it
"from a seven speed down tube shifter,
"to a one-by 10 speed down tube shifting.
"My question is two-fold."
So really you got two questions.
"Can I fit a 10 speed cassette?
"I've measured the rear dropout to 130 millimeters,
"and secondly, is the down tube shifter capable
"of being indexed for 10 cogs?
"Thanks."
Good news here.
Right, 130 millimeters is what you need for 10 speed,
so absolutely fine, just make sure of course
that the cassette is going to fit
on the freehub and everything.
As for your gear lever being indexed for 10 speed,
no it's not going to be, I'm afraid.
You could put it into friction mode,
if that's possible on your shifters,
but friction mode is really quite hit and miss,
to be honest.
It's just something more to faff around with down there.
The good news is, though,
Shimano actually still do make a down tube 10 speed shifter.
I think it's the SL-7900.
That's what I've got on my old Eddy Merckx
that I sort of rejuvenated into a modern day equivalent
of an old-fashioned race bike, if that makes sense.
So yeah, it is totally possible.
Go ahead and do it, and then submit it into the bike vault.
Right, next up is Al Val,
who says, "Hello from Barcelona."
All right, "Congratulations on the channel
"I ride an aluminium Cannondale CAADX.
"I'm going to replace my aluminium fork
"with a carbon one.
"I'd appreciate any advice about the correct installation
"of the compression plug
"Carbon paste needed?
"Torque of the bolts?
"How to avoid galvanic corrosion
"between the frame and the fork?"
Right, okay.
So you could apply some carbon paste
around the internal of the steerer tube,
before you put the expander bolt in place.
I've never done it.
I don't think I know anyone who actually does that,
but I guess it couldn't do any harm.
As for the torque of the expander plug bolt,
well it does depend on what you're using.
So, some of the really lightweight ones,
they don't recommend torquing them up too much,
whereas some of the beefier ones actually recommend
up to eight Newtonmeters, believe it or not.
Now you mention about avoiding galvanic corrosion.
Well really you need to keep on top of your maintenance,
so make sure the bike's clean,
and you're using grease and lubricant where necessary.
Really, if you're going to start sweating all over it,
you are going to get a little bit of corrosion,
so yeah, just make sure you wash the bike
as and when it's necessary.
Next up is Michael Field, and Michael says,
"Jon, when climbing and swing the bike side to side,
"I can hear the front disc rubbing
"when it's at full tilt.
"Is this normal, or can I stop it happening?
"I've centered the caliper.
"Thanks."
Right, it's not totally normal,
but it is normal to have a little bit of flex
in between a frame and a wheel,
or a fork and a wheel, in your case.
Something here to consider really,
is that with disc brakes the tolerances
are way closer than with rim brakes.
In rim brakes we tend to have a few millimeters
either side of the rim, where the brake pads are,
whereas on disc brakes, it's a lot, lot closer,
so any discrepancies are much easier noticed.
I mean we hear it on rim brakes, for instance, too.
Normally a lot more when the weather's actually wet,
rather than in the dry.
Something here to consider
is that maybe your disc brakes need bleeding,
to try and get the pistons to retract fully.
Alternatively they just need cleaning a little bit,
to try and help them move in and outwards.
Just give it a blast with some disc brake cleaner.
But yeah, it's not that normal,
but it is something that can be picked up
with someone with very good hearing like you.
And the final one this week comes in from Glenn Fullwood,
who says, "Hi Jon, I look forward
"to the GCN Tech Clinic each week."
That's good to hear, Glenn.
"I have a compact chainset, 50/34,
"that came with my Bianchi.
"I live in Southwestern Australia,
"where it's almost as flat as a pancake.
"I very rarely use the 34 tooth chainring,
"but when I do, it's always in smally smalls,
"50/12, 50/13."
Ah, I reckon they mean 34/12, or 34/13,
but it's acceptable.
"As I feel that the 34 tooth chainring is wasted,
"can I change it for a 42 or 44?
"will an inner chainring as big as 44 not work
"with the 50, or is this not a wise idea?
"Look forward to hearing back, Glenn."
Glenn, lovely part of the world out there in Australia.
I look forward to my annual visit each and every year.
Right, okay, it's absolutely fine
to put a 42 or 44 inner ring on there,
and if anything, you're going to get even snappier shifting
from your front derailleur.
Something to consider though,
44 tooth chainrings aren't generally that common,
so it could be a little bit more difficult to find,
but a 42 is going to be a piece of cake for you.
So you go ahead, fit that.
No more smally smalls out there for you at all.
Right, I hope I've been able to help answer
or solve your problem this week.
If not, leave it for me down there
in the Comments section below, using the #ASKGCNTECH,
and I'll do my very best to answer it
in an upcoming episode.
As ever, remember to like and share this video
with your friends too,
and don't forget to check out the GCN Shop,
at shop.globalcyclingnetwork.com.
And now, for two more great videos,
how about clicking just down here,
and just down here.