Alex: Welcome to the GCN Tech Clinic where we aim to answer the questions you've submitted using the
#ASKGCNTECH. We hopefully get through a good few today and straight to it. First up, we have got,
"Is straightening a bent derailleur hanger, is there a risk of damaging a carbon frame?" Well
there is always a slight risk of damaging a carbon frame but my first bit of advice is
always to avoid trying to straighten a bent mech hanger because it gets significantly
weakened and you do run the risk of it breaking then when you're out on a ride.
The best advice is to always carry a spare one with you for your frame.
If you are going to straighten that mech hanger out, it's important to make sure you
leave the wheel secured into the frame and that will avoid putting unnecessary stress
through the small bolts that attach it to the frame because that's the point where you
could risk damaging the frame. Keep it secure and then you shouldn't run into any trouble.
Next up, we've got David Hughson who's asked where can he buy the same touch up paint that
was used on his bike. That's a good question because, well, some brands will list that on
their website and you can buy that relative to the color of your bike and they'll also
list the paint codes that the bike is painted in. If you can't buy it from the company directly, you
can go to specialist paint shops that'll make up the color of paint that you need and you can buy
a little pot from it there. Also, many car body shops will be able to make up the paint that you
need. Even if you don't know the code, take the bike there and they'll be able to match that up.
Next up, we've got Keder Kulkarni with their question, which as I read it, I think is a bit
of a funny one but we'll see in a second. They say if they're running a 6-watt LED headlight,
are they losing 6 watts of power and if they run a 6-watt or higher power rear light, can they
gain that power back? They say they used to have such questions in their physics classes. Well,
I think it is a bit of a fun one because if you've got a headlight on the bike, it's not going
to slow you down. Equally, if you have a really bright taillight, it's not going to speed you up.
Even though the wattage of the light is written on the light, it's not going to slow you down.
Although, it does lead me to the question of Ollie does always have a rear light on his bike.
Maybe he knows something I don't and he's gaining that extra power from it.
Unfortunately, for most, I don't think it’s going to make any difference whatsoever.
Next in we've got JeiHeino who asks, "Hi. Do I have to disconnect my disc brake hoses
whilst changing the handlebar? Do I need to bleed brakes?" Also, they asked do they need to replace
the olives on the brake hoses? A few different questions in there but if you are going to break
the hydraulic system open you don't always have to bleed the system because providing you don't pull
the brake lever or lose any fluid, you can put it back together and sometimes get away without
needing to bleed the system, which is good. Unfortunately, though, if you do pull the brake
lever or lose any fluid out of the system then yes, you are going to have to bleed it and get rid
of all the air that's in there because otherwise your brakes just won't work very well. I've done
it quite a few times actually, where you can open the system up or even change the hoses round left
and right if you want to change the front and rear brakes round. You can get away with it, but
you're going to have to be a little bit mindful of it just to make sure your brakes are working.
Next up, we've got Will Richardson, who asks, they recently bought a Wahoo Kickr
for the winter and have noticed that they're actually feeling really uncomfortable on the
saddle or a bit of numbness when they're using it. They say this doesn't happen when they're
out on the road but is wondering if there's any reasons for this because out on the road,
all of the parts are the same, just when he's indoors, but he's not very comfortable.
This is actually a common problem that lots of people find when they ride it indoors on the
static trainers. It’s because you're in a static position so you're not moving about on the bike
anything like as much as you are when you're out on the road. Therefore, you quite often don't get
out of the saddle for prolonged periods of time and that’s why you're getting uncomfortable and
a bit of numbness on the bike, which, well, it’s just not great for anybody, is it? It's important
when you're riding indoors, try to be a little bit mindful of now and again to get out of the
saddle and relieve a bit of pressure, move around and it'll help your shoulders and your back too.
Onto our next question, we’ve got Crikky. Is that what their name is? Interesting. Recently
their chain fell off as they were cycling and they had a bit of a hard time putting it back on.
Can we give some advice and tips on how to put the chain back on fast and efficiently? When
your chain falls off, it is pretty rubbish, isn't it? No one enjoys that. It's worth
checking your front mech limit screws as well because they might be the reason behind that,
but sometimes your chain does just fall off for no apparent reason and it is very annoying.
If your chain has fallen off on the inside of the chainset,
in towards the frame, it's important to stop pedaling straight away, otherwise,
you do run the risk of damaging your frame when the chain gets
pulled all the way round and could at least damage the paint as well as the actual frame itself.
If the chain has fallen off on the inside, one little trick that you can sometimes get away with-
-is shifting the front derailleur into the big chain ring and very carefully, pedaling because
sometimes the chain will hook itself back onto the chain rings and you could get away with that.
If that's not going to work for you, the sure, tried and tested method of doing this is to
take the tension off of the chain with the rear derailleur cage. Push that all the way round
and then using your other hand, carefully guide the chain back onto the chain rings.
Your chances are you're going to get pretty grubby and greasy fingers so it is worth trying
to keep some nitrile gloves in your saddle bag, or using a stick, or if you want to go all out,
maybe use some leaves nearby because that will help keep your hands nice and clean.
Onto our final question this week, and it comes in from Savas Anibal,
so thanks very much. They're asking, they've changed their crank arm length from 172.5
millimeters to 165 millimeters and do they need to lift their saddle, and if yes, by how much?
That's a good question because obviously, changing your crank length is going to have an impact on
your position on the bike. You are going to have to put your saddle up. Because the cranks have got
shorter you're going to have to account for that. The difference in crank length that you've got is
7.5 millimeters but you're not going to have to adjust the cranks quite that much. I'd suggest
maybe a change of about 5 millimeters and then try that out. Then if you need to change it
afterwards, you can make some minor adjustments up or down as you feel necessary. One thing it is
important to note of is when you're changing the saddle height it will have an impact
on the setback of your saddle because obviously, the seat tube is at a slight angle. As you put the
saddle up, it's going to shift the saddle back slightly so it's worth checking that as well.
That rounds off another GCN Tech Clinic this week. Thanks very much for all your questions.
Please do keep them coming down in the comments section below using the #ASKGCNTECH. Thanks
very much. See you later. [00:06:48] [END OF AUDIO]