- Welcome to the Tech Clinic.
Unfortunately, Jon couldn't make it today, because,
- I've been snowed in.
Can't even get out of my gate.
Although people are walking through my field
to go sledding, but don't worry,
normal service will resume shortly.
- However, fear not.
I have braved the treacherous arctic conditions,
and managed to get in to GCN Towers,
so I can answer your tech questions.
Now before we get stuck in,
remember, you can submit your questions
using the hashtag #ASKGCNTECH.
First question this week is from Mike Gapter,
who says, I have a Tommasini Tecco,
with Campagnolo Chorus 10 speed.
Gearing is 52/39, with an 11/25 cassette.
Well, my knees are as young as they used to be,
but I want to change the cassette out for an 11/30.
I've been told by my local bike shop
that I cannot use the derailleur cage
that's currently on it, as it's too short,
and no longer cage is available for it in Campy offerings.
Can you offer any options that might work?
Well, first thing, Mike, good to hear from you,
and a Tommasini, nice bike.
I happen to know Jon is a fan of those too.
The easiest and simple thing you can do,
is get a derailleur hanger extender,
and this will drop the derailleur
just a couple of centimeters lower,
and they're really easy to fit,
and best of all, you can get them
for just a couple of quid on Ebay usually as well,
so, yeah, sorted.
Next question is from Luca Bizjak,
who says, hi Jon, love the show.
As always, great info.
I've got a question: I'm thinking about
an upgrade/downgrade, meaning going
from old Ultegra 6500 to the newer,
but lower, 105 7000.
This would fit, right?
I'm uncertain, especially for
what concerns the bottom bracket.
Would you go for this upgrade, or downgrade?
The main usage of my bike at the moment
is on my indoor trainer,
but sometimes I also take it outdoors.
Thanks for the help.
Cheers, Luca, bye.
Cool, right, well, it would work fine.
And also, in terms of the older Ultegra
to the newer 105, I actually truly believe
that this is actually an upgrade.
The difference between those two groupsets is pretty big,
and the shifting performance of the new 105 is brilliant,
which you may have seen in the blindfold test we did
of 105 versus Dura-Ace.
If you've not seen that video, check it out.
It's a good one.
But yeah, the 105's really good.
Regarding the bottom bracket for your new groupset,
it will fit, because they're both compatible,
and you'll have a Hollowtech II bottom bracket as well,
which, that system, as opposed
to the octalink system you've got,
so that system will actually save a load of weight too,
as an added bonus.
So yeah, I'd say absolutely go for it.
Question from David Konecny now, who says,
any tips for winter cyclocross bike storage options?
Muddy conditions, plus having to park my bike
in my apartment, is not really an elegant solution.
I honestly can't be bothered to clean the bike
after every short ride.
Mostly it's just the wheels and frame
where the mud accumulates, not the drivetrain.
Well I think ideal for something like this
would be a turbo training mat,
as it's the right size and proportions of a bike,
and it will sort of catch any dirt
that falls off the bike in your apartment.
You can sort of park it on there,
and then you can also hose down turbo training mats as well,
and clean them later outside if you need to.
The other thing is, if you drive to a cyclocross race,
and you're on your way home,
and you live in an apartment,
and it's hard for you to clean your bike,
then something that my brother does
is stops, past a petrol station,
where they've got a jet washer,
and just quickly blasts his bike for a few minutes,
and it gets rid of most of the dirt,
obviously avoiding the crucial areas,
such as bottom bracket, bearings,
but yeah, it does a really quick job
of getting all the mud off
in a very short space of time.
Thijs Vanballenberghe asks, hi John, love the show.
Do I benefit a lot by buying a bike
with electronic shifting, instead of mechanical?
I don't compete in races,
I just ride 10000K a year, including some sportives,
like Les Trois Ballons.
The difference in price is 1300 euros,
between the bikes that I'm considering,
and one has 105 on it, the other has Ultegra Di2.
Thanks a lot.
Just 10000K a year?
I assume you mean 10K a year, but joking aside,
it's quite a tough one, this.
I love electronic gears,
and I really like racing on them,
because I never experienced a mis-shift at all.
If I wasn't racing on it,
then I'd be less bothered about using electronic gears,
but, ultimately the shifting performance with Di2 is superb.
Ultegra level as well,
it's better than any mechanical shifting, in my opinion.
It's absolutely brilliant.
And once you've experienced it,
it's very hard to go back to mechanical shifting.
And, I would say that, if you can afford it,
and will get enjoyment from it,
then why not upgrade to it?
And I'd also say that you certainly don't need
to be racing, in order to justify Di2.
We have a question from Doug Morley now,
who says, last year I bought a Ridley Fenix.
An excellent machine.
It is, good choice.
I found it harder going than my other bike,
which was a Ribble HF 83.
The problem seems to be the bottom bracket,
which is a press fit BB86,
and it's very stiff, but apparently smooth.
The Ribble has a 68 millimeter
external screw fit bottom bracket,
and spins very freely.
Why should the BB86 on the new bike be so stiff?
Well, the BB86 could have better seals,
or perhaps it's not yet fully worn in,
which is a thing that can happen.
So it could take a little while,
a bit of riding for it to free up.
The other thing to consider,
and this is probably the worst case scenario,
is that the BB shell is not perfectly symmetrical,
and this means that the bearing cups
are not perfectly in line,
and so the axle, as it goes through
from the chainset, is not able to turn
as freely as possible.
Threaded bottom bracket shells
are generally tapped out together,
so they're perfectly in line with one another,
and the BB's spin really smooth, which is great.
But, if it is the fact that the cups
are not perfectly symmetrical,
then it's worth probably taking it to your bike shop
where you got it, and getting them
to have a look at it and assess it.
A question from Igic Dacic now.
Sorry if I've completely mispronounced your name there.
But he says hi Jon, I've bought a BMC SLR01,
with Ultegra R8000 on it.
Sounds like a really nice bike that.
And after a few months, I converted it
to SRAM Red ETAP.
After he's done all this, he says I notice
that the dropout didn't match,
and I have to buy a new one,
the one that matches for the SRAM groupset.
Why is this the case?
Why did Shimano do that?
Thanks, which is spelled t-n-x.
Well, there is an answer to this,
and it's that they, the dropout,
is designed for the new Shadow design rear mech,
which enables the rear derailleur
on the newer Shimano groupsets
to sit closer into the cassette,
and this means that you get less flex in the system,
and more precise gear shifting,
as the derailleur is moved inwards.
And it also means that the whole system
has a slimmer profile as well.
And at the moment, SRAM is different from this,
and that's why you need a different hanger
for SRAM and Shimano on that generation.
Varga Pal asks, Hi Jon,
I have a problem with indexing my rear gears,
which run Shimano 105 5800.
I follow the instructions from your related video,
and it works fine on the stand,
but in real action, when I try and select the smallest cog,
usually I fail.
The chain stays on the second smallest cog.
Should I change the cable?
Thanks.
Hi Varga.
I would say, by all means, try another cable,
and see if that resolves the issue,
because that could be the problem.
But something else that could be causing it,
is that when you're riding in the smaller sprockets
on the block, you're generally putting more flex
and strain through the system.
You might even be out the saddle,
and that can sometimes mean
that the chain can't get into
that tiny sprocket at the back.
So one other thing you can try,
is to undo the H screw a tiny little bit more at the back,
and see if that resolves the issue.
Jimmy Liao asks, are there any rules
on the size of disc rotors that you should run?
140 millimeter all around, or 160 millimeter all around?
Is there any reason why anyone would run a 160 front,
and a 140 millimeter rotor rear?
Hi there Jimmy, there are no rules
regarding the size of rotors that you run,
but something worth thinking about, I guess,
is that most of the pro riders
that we're seeing at the moment
are running 160 front, and 140 rear.
Now the reason many would have a 160 at the front,
is because most of your braking forces,
especially when you're going downhill,
are at the front.
The front brake does more of the work.
And by having a larger rotor,
you can dissipate more heat,
more quickly than a smaller 140 rotor.
There's a slight weight saving as well,
by having a smaller rotor at the back.
But, if you're a lighter rider,
then there's no means really, I'd say,
with why you can't have a 140 at the front as well.
So, yeah, there are no rules.
Karl Pan has a question on keeping his bike
looking nice and clean.
He says, do you recommend waxing the frame, and fork,
so you always have that shiny new look,
and it protects it from grime?
If yes, would car wax do?
My bike is fully carbon.
Karl, yes, I do recommend you do this.
I've done it before, and I know that Jon does it,
as soon as he gets a new bike as well,
and periodically does it a few times throughout the year,
to keep his bikes looking absolutely tip top.
If you're gonna do it, car wax is absolutely fine,
but if you've got a matte finish on your bike,
then make sure you go for a specific matte product,
as on a microscopic level,
the surface of matte finishes are full of little gaps,
and some waxes can get clogged in those gaps,
and reduce the matte appearance of that finish.
Another thing to think about,
is ceramic coatings that are applied
increasingly to fancy cars these days.
These are really hydrophobic,
so they're excellent at stopping dirt
from sticking to your frame.
Makes it easy to wash it off as well,
so, you might want to look into that as well.
David Rynda has a question now.
I wonder if he's related to Judge Rynda?
Nah, spelled differently.
Anyway, he asks, hi GCN,
I recently acquired a Trek 5200 with Dura-Ace 7700,
a nine speed groupset.
I'm interested in upgrading the crank
and bottom bracket, rather than doing maintenance
on the ocatlink spindle.
Some sources say I could use a 10 speed crank,
but I'm worried that will cause compromises
in the shifting/general functioning.
What current cranks would work well with this setup?
Thanks.
Well, hi David.
Those octalink adjustable spindles are very fiddly, I agree,
but you can get the fully sealed ones still,
and you could continue to use your Dura-Ace chainset.
Those old 7700 chainsets, they look really nice,
so that would be cool,
but you would be okay using a 10 speed crank,
and even an 11 speed crank too.
I've done it.
It works totally fine.
Last question this week comes from Zac Snow, topical.
Now, Zac asks, love this segment on GCN.
Thanks Zac.
And then he asks Jon,
what is the most efficient pedaling system?
Shimano, Speedplay, Look, or Time?
Right, Zac, dude, this is a can of worms.
Every single brand of pedals
makes their own claims about them being the most efficient,
and the truth is it's very hard
to scientifically properly test this,
because it relies on people,
and peoples' biomechanics are generally very different.
That said, if you've got a worn out cleat,
that can affect your efficiency,
as it can cause your foot to rock on the pedal.
Something else is cleat position.
Very important for maximizing efficiency.
And if you're not convinced about your cleat
being in the most efficient place,
then a bike fit is really useful at fixing that.
The other thing to consider,
is that Speedplay and Time pedals
generally offer a bit more float in them,
than Look and Shimano pedals.
Now this isn't something that's necessary for everyone,
but some people really like it.
Right, that's it for this week.
I hope you've found these questions and answers useful,
and if you have, then give the video a thumbs up,
and please subscribe to our channel.
Let's hope that Jon makes it out the snow alive,
in time for next week.
And in the meantime, why not check out his excellent video,
where we went to visit Rob Hayles,
to see some homemade, custom carbon fiber tech.
It's a good one, down here.
Right, bye.