﻿Welcome to the GCN Tech Clinic where
we aim to answer your bike and bike tech-related questions and issues.
If you'd like to get your questions into as you can do using the hashtag
ASKGCNTECH in the comment section
down below or on other forms of social media
as well, and we'll try and answer as many of them as we can.
First up we're not further ado, this week we have a question from Kevin
Timmons who says "Ollie, since you're the experts on marginal aero gains,
does sunscreen/sunblock make you more aero?"
Well, Kevin, if I could offer you only one tip for the future,
sunscreen would be it.
The long-term benefits of sunscreen have been proved by scientists,
whereas the rest of my advice has no basis more reliable
than my own meandering experience.
I will dispense that advice now. There you go.
The next question is from Darren Clare who says,
"Can you recommend a degreaser or hack or do I need to purchase
a specific kind of degreaser?"
Yes, I would say any organic solvent will pretty much work.
I'd avoid really potent solvents because they could potentially damage
your frame, but you should be okay with petrol and white spirit,
acetone is pretty polar might rip your frame, I wouldn't use that.
My favorites organic solvent, dichloromethane,
I'd quite like to try that, but it's another one for GCN
Tech after dark so we don't need to go into that.
However, if you are washing stuff down the drain
I would say purchase specific products because there are products
available now that are more environmentally friendly
and are designed to be washed down the drain.
A lot of organic solvents should be disposed of in dust really
in solvent waste, so I would say try and avoid using those.
If you can get your hands on proper bio degreaser or something do it.
Next one is for a Mads Buus Olsen who says "Hi, GCN, love your show.
I was wondering if it's possible to throw a Dura Ace rotor
on a Shimano 105 disc brake caliper.
What do you have to be aware of?"
That should be absolutely fine as long as the rotor diameter is the same
so that, the dark what?
Is that a 140 or 160, that's a 160 on mine.
You need to make sure it's also the same diameter.
Something to be aware of though is that Shimano when they knew,
they obviously we're down, but when they're new, they're 1.8
millimeters thick.
That's the rotor thickness, whereas SRAM start out at 1.85 millimeters
or even 1.9 millimeters in some of the smaller of like 140s.
In an emergency, if you were getting, I don't know
a neutral service weõll or something and you needed to put in a ceram
disc rotor into a Shimano thing, it could potentially work, but it might
rub because the rotor is that bit thicker
whereas the other way around it'll work.
The braking is not as optimal because the interface
for the pad and the rotor is not as good but it does work.
I've done that. There you go.
Cam packs narrower as well that's usually at 1.8 mil thick when they new.
Next question is from Random Asian
who says, "Hi Ollie should I get ceramic bearings
and ceramic jockey wheels is it really worth it?"
Well, Random Asian,
if you can afford it and you want to do
it and you want to bling your bike out go for it.
Why not, but if it was me, I see
ceramic bearings as the cherry on top of the Schwarz
of Al-bakr shorter Black Forest gateau.
In that respect, I'd say, ask yourself
or I'd ask myself, have you done everything else.
Have you got latex inner tubes, have you
got aero wheels power meter, have you optimized your position
on the bike and become as aero as possible
and clothing and things like that,
because they're all things that offer greater performance
more bang for your buck, so I'd probably
do those things first but it's up to you.
That's one of the great things about freedom of will.
Now, the next question is from Luke Jackson
"I was supposed to be doing the Fred Whitton
for the first time this year but it's been canceled. I live in the Lakes.
That's at Lake District in the UK, national park, beautiful place.
He knows how hard it will be but can I give him any advice on completing it?
I love that event, man.
I've done it a few times and I love the Lake District.
It's one of my favorite places and in fact, it's going to be
one of the first places I go to when the lock-down ends because
it's such a beautiful part of the UK.
I'd say, if you live in the Lake District, you have no excuse.
Sorry but I'ds they practice on the 30% hills as much as you can.
Get used to riding there's really steep climbs
and build the strength required for that.
Also, fit a 32 cassette but you probably knew those things already.
For anyone else that doesn't know, that's the best advice.
Next question is from Lukas Svendsen.
“Hello guys, love your knowledge.
As a student and always on a budget,
will it be smarter for me to buy a bike with Shimano 105
instead of Ultegra because of the savings when
certain parts start to wear out and need replacing?”
Yes, I think you're right like, when you look at the cost of, say,
a Shimano 105 chain over an Ultegra one, it's like twice the price.
Like, the cassette, it's like twice the price.
Is it twice the performance?
I'd say no. The Ultegra one, and that is slightly lighter.
The Ultegra chain, it's been shown to be slightly lower friction.
It's slightly faster, maybe like a watt or something but very little.
Yes, twice the price but it's not twice the watt saved.
If you're on a budget, I would definitely say get 105.
When I was a student and I was on a budget,
I bought a Cannondale SuperSix and I'd save up for ages to get it,
with 105 on it, and it was amazing.
It did everything I needed it to do and yes, I think
if I were to make that choice again, I would buy 105
at that point in my life again.
Also, 105 is so good, like we've done,
I don't know if you've seen it but I did a video with Psy,
where we did a blind test where we were trying to guess
if we were using Dura-Ace mechanical or 105 and genuinely,
can't tell the difference. 11 speed 105 is so good these days that
the shifting is absolutely, is brilliant, so I'll go for it.
Save your money and you can always put the money saved
towards something else like aero wheels,
which will probably give you a more bang for your buck
in terms of performance than the difference
from the step up from 105 to Ultegra.
Yes, I would think along those lines.
Plus, you can always potentially upgrade
your 105 shifters in bits and pieces further down the line if you
get a bit more money or whatever. Yes, go with that.
105 is a mint, probably.
Anush LTI. Yes, Anush.
“Could I use a pinch of salt in water while
training indoors instead of using salt tablets?”
Yes, you can or you could also do it when you're training outdoors
if it's a hot day. It doesn't really matter.
If you're feeling particularly middle-class, may I recommend
Maldon sea salt flakes?
It's quite a nice salt that.
Yes, also bear in mind that if you're making food, a lot of food does have
salt in it as well, so you are actually getting quite a bit of sodium from.
If you have rice cakes there's quite a bit of salt
in the cheese that you would put in the standard recipes.
You're getting salt there. Even if you're having
energy bars, a lot of them do contain salts and gels and things but yes,
it's a cost-effective thing, bit of salt in your water bowl, go for it.
Next question is from Jabin Lim, who says, “Hey there.
I recently changed my KMC X11 SL DLC chain,
and the chain keeps skipping on the smallest sprocket.
Is it possible that my smallest sprocket has worn out
or is it just that the chain needs to stretch a bit more? Thank you.”
Oh, well, it's not down to chain stretch. You don't want your chain
to stretch, and someone pointed this out correctly.
We often talk about chain stretch and chain wear.
It's not technically the chain stretching.
It is the wear within the chain links.
It could be that your cassette
is slightly worn, so if you've just replaced your
chain and your previous chain worn out a lot, it's
like worn out, the cassette as well, at which point, you do then need to
change your cassette and your chain at the same time usually.
You can usually get away with the chain rings though.
They should be okay but it could also be down to the set up if you reenact.
I'd pay attention to this.
Whether it being the smallest ring at the back, it could be that your
lower limit screw needs adjusting.
If you turn the lower limit screw or move
the derailleur inboard and outboard
and you need to get that perfectly in line with the smallest cogs.
Check your lower limit is set properly.
We've got videos that can show you how to do that as well
or if it's not the limit, the limit's fine, it could just be the indexing
needs to be just tweaked and sorted out.
While that wasn't a problem with your old chain running,
now you've fitted a new one, it just needs to be tweaked slightly.
It could just be that.
Let us know how you get on and if you have any issues with that
just drop us another comment in the comment section.
Next question is from Marcus Antonio Emia who asks,
"Hey, is it possible or okay to ride fixed gear
or track bikes in a busy or traffic street?" I would say no.
[chuckles] Don't do it. I don't know what the rules are
in every country in the world but I do know what we have in the UK
and that is under the Highway Code. Your bike has to have brakes.
If your bike doesn't have brakes, technically it should be
fitted with lights at night as well and reflectors during the day.
The issue you've got is if you are in an accident
which is probably the likelihood of that is
going to be increased by not having brakes especially when you want to
run on a busy street, then you become liable in the eyes of the law
and culpable for causing the accident because your
bike wasn't properly fitted with brakes.
I would say, don't do it.
Some people think they're cool and it's a hipster thing to do and ride
fixies in the street but unless it's got a brake on it don't do it,
I would be what I'd advise.
The next question is from JPLSenpai who says,
"Hey guys, quick question regarding cleats.
I recently noticed that one of mine is way more worn out that the other
possibly because that's the one I disengage with when I come to a stop.
If this is the case what's better, swap it with the other side shoe
[scoffs] or swap them over, or just buy new
cleats and replace both at the same time?"
I would just buy a new pair and just replace both at the same time.
It's important you do this and it's something
that I've fallen foul of in the past, years ago.
A lot of people don't realize how much their cleats have worn.
Once your cleat has worn lots, what you'll find is that the shoe
will move a lot more within the pedal and it'll be a lot looser.
What this can cause then is bad
knee alignment and then that can cause knee issues
and aggravation further down the line as you're peddling along.
Yes, always replace your cleats because they do become loose.
Anyway, just replace both at the same time.
The last question this week is from Zachary Starkey who says,
"I'm riding on tubeless tires for the first time." Nice one.
"From the look of your other videos there are a lot of great benefits.
However, I'm wondering, is it okay to put tubes
in them if there's a puncture and it won't seal?
Any downsides to running tubes inside of tubeless tires?"
Well, the downside is that you don't get the benefits of the tubeless system.
You don't have that puncture protection of the sealant.
You don't the lower weight of sealant compared to a new tube
and you don't have the lower rolling resistance
of a sealant compared to running tubes which adds a bit more
friction although some people say that's more down to the construction
of the tire than the inclusion of the inner tube,
but that's another story altogether.
The other downside is that trying to get the tire off,
trying to get a tubeless tire off requires a bit more effort
than getting a normal clincher off and that's
usually because the bead is stiffer. This is because it needs to
create an airtight seal against the wheel
so it usually has a stiffer construction.
That can be a bit more difficult but if you really
need to put in a tube then that's what you do. It can be done.
I've done it in the past but very rarely does it happen because
tubeless is if you use a good sealant that seals most punctures.
Then, if you get a puncture that won't seal you can out a tire plug
in there as well and that usually gets it to seal most of the time.
Very rarely do you get to the point where you've to
put an inner tube but in my experience, it can happen.
There, now you know but I would say tubeless is great.
Keep up to it.
Well, I hope you've enjoyed this edition of the GCN Tech Clinic.
As ever, if you want a sports channel, GCN shop.globalcyclingnetwork,
and grab yourself a mug and give this video a like
if you enjoyed my Baz Luhrmann reference right at the start of the video.
I'd like to say I got that right in one take but that would be a lie.
[laughs]
All right. See you next time.
AskGCNTech, that's how you get your questions in.
Ciao.