– 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 And also remember to
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