GCN Tech Clinic: Power meters, thru-axles and chain wax

We are back in the workshop with Ollie and Alex for this week's GCN Tech Clinic, taking a look at some of your tech questions from cleaning your bike to the efficiency of power meters.

Can I use car brake cleaner on my bike?

Car brake cleaner is designed to remove the same sorts of contaminants, oils and particulates that a bike specific cleaner is. In terms of its properties as a cleaning product any brake cleaner will do a similar job, however it is worth checking what the warning labels on the cleaner say.

They are intended to be used on car-specific brakes and can be more aggressive and concentrated than bike friendly ones. This could cause damage to decals and bar tape if it is particularly strong.

Will a power meter still work with an e-bike?

This is a really good question that has been raised by one of our viewers. With the mechanical assistance provided by the motor, will a power meter still read accurately in regards to the power produced solely by the rider?

Luckily both crank and pedal based power meters only record the effort put in by the rider and neglect the input of the motor. It currently isn’t possible to record a total output figure of the motor and your own input combined however e-bikes do offer different levels of assistance so you can tailor their input to meet your needs.

Also, if you have a power meter that records your own output, just focus on sticking to outputs that you are happy with and use the motor to aid this when you get to tough sections during a ride.

Why is my cassette making a clicking noise?

If you are experiencing a clicking noise coming from your cassette there are a couple of things that could be causing the annoying sound. Firstly start by looking at the rear derailleur and making sure that the gears are meshing correctly - if your gears need a tune this could be the culprit for the clicking.

Pedal your bike by hand and watch the cassette - if the chain is trying to jump up or down the cassette this is a tell-tale sign that the cable tension may need adjusting. If that doesn’t look to be the issue, the next place to check would be the actual mech hanger itself. This is the small piece of metal between the frame and the derailleur. If this is loose or bent this can be causing the issues with the cassette. If you are unsure if your hanger is bent, a good local bike shop will have a tool for checking its alignment.

Lastly if none of the above have helped, it could be that it is time to replace the drivetrain as worn and tired parts will start to degrade their performance and develop these clicking sounds.

Is there any loss of power by using a power meter?

It is understandable to think that anything that measures an output of some description must also consume a little bit of that energy in order to measure it. When it comes to power meters on bikes this is not the case and there is no loss in power.

The way power meters read your output is with a very small strain gauge that is laid along the crank or pedal and measures the natural microscopic deflections in the material as you generate force. This process of deflection will happen regardless of the presence of a strain gauge so rest assured there is no loss to running a power meter over not running one.

How can I prevent my thru-axle from seizing?

Depending on how you travel with your bike and how you store it, taking your wheels out might not be all that frequent of an occurrence. It is important that when the time does come for the wheels to be removed that the thru-axles are not seized into the frame.

It is recommended that regardless of whether it is necessary, you should loosen, remove and refit your thru-axles from time to time to ensure that they aren’t seizing. A good practice to adopt with thru-axles is to apply a small amount of grease along the length of the axle - this acts as an anti-seize compound that should allow for the axle to be removed without stress.

The other thing to note is that thru-axles will have a recommended torque range, and this should always be followed. If you over tighten a thru-axle you run the risk of the expansion bolt getting forced into the frame or fork with such force that it becomes stuck and therefore seizes your axle.

Do waxed chains rust?

Chain wax is an incredibly good lubricant, with marked and significant performance benefits to drivetrain efficiency. It does this by smoothing the surface of the chain on a microscopic level to allow for the rollers and pins to work seamlessly with very little friction losses. Unlike a conventional oil based lubricant, chain wax does not have any intrinsic properties as a corrosion inhibitor.

The only real way that wax can protect against corrosion is with full coverage and acting as a barrier to moisture. If the chain has gaps where the wax does not have coverage then this is where corrosion can begin to build. If this is starting to happen, firstly try and remove any corrosion with a wire brush before going through the process of re-waxing the chain.

How many times can paraffin wax be reused?

Chain wax has a theoretical endless lifecycle, as long as it remains within the specified environment. For most waxes that would mean not exceeding 70 degrees Celsius, however it is always worth checking with the individual manufacturer on this exact figure. It is more likely that over time some contaminants build up in the wax and that marks time to replace it to prevent introducing contamination to the system.

Have a tech question you need answering? Head over to this week’s Tech Clinic video over on the GCN Tech YouTube channel and add your question to the comments along with #ASKGCNTECH.

Alex Paton

GCN Tech Presenter

Impressive sprinter - quite possibly the fastest member of the GCN team