- Welcome to the GCN Tech clinic where I aim to help and
solve your tech related problems.
So if you've got one, make sure you leave it down there
in the comments section below.
If not, well, leave it on social media
using the hashtag
#askgcntech.
As ever, let's crack on with the first question this week.
And it comes in from Dennis Flakla.
Now Dennis says, Hi Jon I would like to change all of my
group set for Ultegra Di2 for the new Dura ace Di2 9150.
Do I need to change the wires
or can I just replace the components?
Dennis, good news here.
All Di2 group sets are totally compatible
other than the first ever one, which was the 7970.
Because that group set, the 7970,
used a five wire connecting cable system
as opposed to the new setups that all use a two wire
control area network cable.
So you're, well, ready and willing to go really.
And just upgrade all those components
without having to change the wires importantly,
particularly if you've got internal cables which,
sometimes be a little bit fiddly.
Next up is John Park.
Now John Park has a question which I'm going to
shorten down a little bit.
He wants to know can he use a mountain bike group set disc
brake calipers with road bike brake levers, all hydraulic.
Yes, you can John.
Because while they're all cross compatible,
there's a little bit of a pun there,
because they all use mineral oil
to actually control the system.
And in fact, Matthew Van Der Pol,
the Cyclocross sensation, he used to use XTR disc brake
calipers with road brake levers.
So yeah, it worked absolutely fine.
If it's good enough for Matthew Van Der Pol,
it's good enough for you John.
Go ahead and try it.
Right. Next up we've got Mike Davies who's from Australia.
A place I love because I've just come back from there.
Right, anyway, Mike wants to know.
He's got a question.
On his bike he's running Ultegra 8070 Di2 and he's looking
to replace the disc rotors and has a couple of questions.
Firstly, will the DuraAce SM-RT900 rotors be compatible with
the Ultegra 8070 calipers?
And secondly, the bike comes with 160 millimeter rotor
on the front and rear and where he lives is not very
mountainous and wants to know
should he use a 140 on the rear.
He believes it is as simple as just removing a spacer
on the rear hydraulic disc brake.
Right. Firstly, those rotors
will work fine with the calipers. No problems there.
As for the 160 and 140 conundrum that you're talking about,
that is probably what most people are opting for these days.
In an ideal world, 90 percent of your braking is going to
come from the front brake levers so 160 millimeter rotors
is gonna give you adequate stopping power on a road bike,
I think.
Especially as you're not on the mains in this area,
like you say.
As for having a 140 on the rear,
that's not a problem either.
In most cases, all you're going to have to do is just
get yourself a slightly smaller rotor.
And then where the caliper mounts onto the frame,
either you're going to have a shim on there or a spacer
which can be reversed or rotated in order to get that
caliper slightly further around
to work with the 140 millimeter rotor.
Or alternatively, there's just a different
spacer you're gonna use.
If you're unsure pop along to your local shop,
they'll be able to help you out.
But a 160 front, 140 rear,
that's what all the pros are going for.
And well Mike, well, be like a pro.
Okay, next up we've got the Shoten Zenjin
or maybe the Shoten Zenjin,
I'm not quite sure how to pronunciate that one but, well,
I gave it a go.
Anyway, they've got themselves, or about to get themselves,
a new carbon road bike from the internet.
Nothing like a new bike days there.
Anyway, they want to know what sort of precautions should
they be taking care of.
So, should they be using grease or no grease?
Special carbon paste?
That's for the seat post.
And also the bike comes with Mavic tubeless wheels,
not carbon.
And also tubeless tires
but they've got inner tube installed.
Is it okay to run such a setup without going tubeless?
Thanks from Eddie in Osaka, Japan.
Love it out there. Right, so.
Personally, I would use carbon paste with your seat post,
where it goes into the frame.
And also, get yourself a torque wrench.
That's probably the best bit of advice I can give
because carbon components are, well,
a little bit fragile, I guess, in the wrong hands.
So make sure you don't over tighten any of those bolts.
Moving on though, to the actual tubeless tires and wheels
where the inner tubes fit it.
Yeah, you can run that.
In fact, a few people if they are out riding and they
get a big slice in a tubeless tire,
it's beyond repair and they can't get home.
Well, the way they get home
is by putting an inner tube inside.
But, alternatively, one will remove that inner tube
and actually run it
and unleash the tubeless benefits to their maximum.
Give it a go and let us know how you're going with
that one Eddie, and enjoy that new bike.
And well, invite me back out to Japan, because I loved it.
Next up is Harry Look.
Now Harry says they've bought themselves a gold chain.
Welcome to the club chain Harry. Love a gold chain.
But it needed cleaning and well they decided to actually
remove it by the quick link and submerge it
for 10 minutes in some degreaser.
Well after doing that apparently,
Harry's chain is super noisy and rough.
I'm afraid to ride with it.
Did I destroy my new chain?
Right then Harry.
Oh, well. You've taken it off, you've submerged it.
So, of course you've probably likely to have washed out
every single little bit of lubricant
from within the rollers and the pins.
So what you're going to have to do,
well, sounds like you've already refixed it onto the bike.
Possibly, not lubricated it quite enough.
So, go around each and every single roller
and pin of that chain.
Start at the quick links, you know where you've started.
Apply a couple of drops from little bottle of lubricant
with a nozzle on it, cause I find that really easy to apply.
Once, you've gone around the whole chain,
simply start bending and flexing those chain links
to try and work all that lubricant inside of the chain.
Wipe away any access. Back pedal.
See if that makes any difference.
If not, apply a couple more drops of lubricant of course
removing any excess and you should be good to go there.
Because when you submerged that chain
in the bath of degreaser,
essentially you washed out all of the lube.
Next up is Andrew Howard.
Now, Andrew is looking to swap out the chain rings
on their cranks from 52/36 to 50/34.
Andrews wants to know though,
will they need to lower the front mech to accommodate the
reduction in diameter of the new outer chain ring.
Right Andrew, in order to get the best possible shifting,
then, yeah, I would certainly recommend it,
because, well, we all strive for perfection. Don't we?
So, once you've fitted on those chain rings,
simply drop that front derailleur down, a very small amount.
You want the derailleur cage to be about one to three
millimeters higher than the outer chain rings.
Pretty important to get that.
Too low, obviously, and well you're not going to be able
to change gear and too high you're not going to be
able to change gear either.
So make sure you do that.
It's worth keeping an eye too,
because you are also going to want to,
if you're using cable operated gears,
so a traditional mechanical setup.
You are also going to want to pull through the cable
a little bit and reclamp it up,
because once you drop it
cable tension will be affected there too.
Right, next up is Mr. Sparky Aprillia.
Sounds like they've gotten themselves a fancy motor bike.
Anyway, Mr. Sparky says,
Jon are you able to run a compact 34 tooth inner ring
and a semi or standard 52/53 outer chain ring?
Lots of steep climbs around Torbay and up on Dartmoor,
so the compact chain set is useful but I find myself
sometimes spinning out on the flats.
Right then.
Providing you've got yourself a suitable chain set,
then yes there is a solution for you.
It comes from a company called Wick Werks
who makes some chain rings that all work absolutely fine.
They run a 34 and I think it's a 53 outer there.
So, you're going to be
certainly catered for on the steep climbs
with a 34 inner ring and a 53 outer ring.
Well you're not gonna be spinning on the flat with that,
I reckon.
And also, I'm pretty sure I did read on Wicks Werks website
that they reckoned the shifting performance is just as good
as the standard 39/53 for instance.
Now obviously, it's quite big gap so that is good to see.
Right, next up we've got Nick Edmondson.
Nicks says that he loves the show.
Be grateful for some guidance.
They've got FSA crank set at the moment
with Shimano front and rear derailleurs.
Bottom bracket is square taper.
The left crank arm thread to the pedal
connection have sheared.
So, that's the pedal thread.
They can't find a replacement arm, the correct length
and with a square taper.
Is it possible to fix the thread
or would I advise to buy a new crank?
If so, do I have to go for Sora or would Tiagra work too?
And also, would I need to change the bottom bracket?
Right, let's tackle these one by one.
First up, I would have a look on something like
Ebay for instance, try and find a replacement chain set.
It's likely to be sold in a pair,
but if you can get one at a bargain price well you can have
a spare right hand crank but you can decent left hand crank.
Do that.
Alternatively, you could possibly save that crank that
you've already got because you could drill out the
grooving thread, I guess I can call that, and you then
insert a helicord inside, which is bonded in place.
And then you can simply thread your pedal back in.
However, that sort of thing might not be
that suitable for yourself.
I don't know quite you're mechanical skills.
But a local bike shop should be able to help you out.
And then, the last option, yeah you could well fit a
Sora or a Tiagra chain set on there.
Both are going to work absolutely fine
with what you've got on the bike currently.
You are likely though too to get an
oversized bottom bracket axle,
which is built into the chain set.
Which means different bottom bracket too,
but you are gonna save quite a bit of weight
over a square tapered bottom bracket.
Those are your options, I reckon,
so the choice is up to you.
An ultimate question this week comes in from Patrick Kelly.
Now Patrick has just bought a 10 speed Ultegra Di2 groupset,
but they noticed the junction box is different to the one
on the Ultegra r8000.
How do I charge this old 10 speed Di2?
Right Patrick, sounds to me like you've got the old
A junction box there, as opposed to the one that goes
in the handle bar or inserted into a frame.
But, how are you gonna charge it up there?
Well have a look at it and you're going to see a
couple of white lines or a couple of grayish lines on there,
and those are your charging indicators,
or battery indicator.
On the other side, so laterally wise, have a look and
there's a tiny little flap there
and you're going to need a sharp nail or a little pick,
something like that, and you can open up that flap
and that is your charging port.
Go ahead, put the charger in there
and recharge that battery.
And the final question comes in from Jacques Swart who says,
they've been considering upgrading the bottom bracket on
their bike with a Shimano SM-BBR60.
According to the online specs the bike should be fitted
with a BBR-S500, so compatibility should be fine,
according to Shimano.
However, when they checked the actual bottom bracket
in the bike they found out it was
fitted with a mountain bike model.
The question is, therefore, two fold.
Why would a mountain bottom bracket
be fitted to a road bike?
And also is it worth upgrading the
bottom bracket to the SM-BR60, if it's compatible?
The Shimano chart doesn't show it.
Right.
One bracket, first up, is going to be totally compatible
because they all use a 24 millimeter inner diameter for
the spindle of the crank,
which is essentially your bottom bracket axle.
As for why is it fitted with a
mountain bike wall bracket,
I don't know.
I wasn't in the factory installing it
but generally those bottom brackets are all very
similar with one another.
The only difference comes from possibly the seals,
they could have some extra seals on there to prevent
mud and water getting in.
It's very common to find these on mountain bikes
and Cyclocross bikes.
There's little upgrades that people do.
But the real difference is certainly
the plastic inner liner,
which separates the two
screw in cups.
It doesn't actually do anything structurally,
it simply prevents water from getting in
and ruining the inside of the bearings there.
So it is going to work absolutely fine
with the mountain bike bottom bracket on there.
I guess the only difference is a
possible extra resistance from having extra seals
or thicker grease inside the bearings.
Is it worth upgrading?
I wouldn't do it unless you really need to do it,
because it's very unlikely you are going
to notice those differences.
The time that I would think about doing it is if I was going
for a record attempt or something like that and you
wanted to squeeze out every little watt from your leg
into the drive train.
Right, I hope that I've been able to help answer
your question this week on the GCN tech clinic.
Remember if you've got a question,
down there, comments section, leave them
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