GCN Tech Clinic: Power meters, tubeless sealant and carbon bike lifespan

Does chain wax still work in the wet and does carbon deteriorate over time?

Clock13:00, Wednesday 15th November 2023

This week in the tech clinic, Alex Paton is reunited with Ollie Bridgewood after a few weeks away. With normal business resumed the boys are here to give you answers to the burning bike-related questions that you have.

This week, wheels and sealants seem to be where the big questions are coming from, but we're also talking about power meters, brakes for gravel, and the lifespan you can expect from a carbon frame.

Do I need double-sided power meter pedals?

As far as the term 'need' is concerned, no, you don't. Single-sided power meter pedals work on their own by calculating the power produced on one side and then simply doubling it. What this means is that using a single-sided power meter does open you up to variability in the readings. If you have a dominant leg then a single-sided power meter will not be able to account for this.

For someone looking for the most accurate power data, a single-sided design is going to leave too much room for error which is where dual-sided power meter pedals come in. Not only do these measure all the power you produce but they also allow you to dive into the data and see the differences in your pedalling dynamics from leg to leg.

Will an aluminium rim brake road bike wheel be strong enough for gravel?

Yes, a modern aluminium rim brake wheel will be strong enough for gravel riding. It might not have the resilience of a gravel-specific rim, however for riding off-road, it will be more than up to the task. The biggest thing to consider with a rim brake road wheel is whether or not the rim and the rim brake can accept a high-volume gravel tyre. Before committing to getting a set of wheels make sure that the recommended maximum tyre width matches up with what you want to run.

Read more: If wider road bike tyres are better, why not go super wide?

Do I need to wax my chain before every ride if I am riding in the rain?

Simply put, chain wax doesn’t last as long in wet conditions as it does in the dry. This does mean that if you find yourself riding in wetter conditions you are going to need to reapply the wax more frequently.

The most important thing to make sure you are doing if you are applying a wax lube is giving it time to dry before riding on it. Most drip-on wax lubricants are water-based and need time for the water to evaporate. This is what allows the wax to dry and offer the lubrication and protection. Riding on a freshly treated chain means that it will wash off as soon as you head through a puddle.

Is a carbon bike the right choice for longevity?

Carbon fibre can be a material that some of us actively choose to avoid. The images of carbon fibre bikes that have been snapped in half often don’t take long to circulate the internet and we have probably all heard horror stories about frames or forks snapping.

We aren’t saying that these don’t happen, much the same as welds failing on steel and aluminium bikes or stress fractures on titanium. Like with everything, there is a big discrepancy between a good and bad quality frame of any material.

As far as the longevity of the material is concerned carbon fibre has no measurable degradation over time. This means that a carbon frame is going to be as strong after five or 10 years as it was when it was made. It is more likely to be damage to the frame from storage, crashing, or clamping that will fatigue the material and cause it to snap.

Is it actually okay to mix different tubeless sealants?

This is a tough question to universally answer and it really does depend on the two sealants that are going to be mixed together. Some are very similar in their chemical composition meaning that mixing them together isn’t going to be the worst thing in the world. However, some sealants will not mix well with others and can compromise the effectiveness of them sealing any punctures.

In an ideal world, any sealant should either be the same as the existing stuff that is in the tyre or the tyre should be cleaned out before having the new sealant added. If the old sealant has dried to the inside of the tyre then it is worth removing it for no other reason than the fact that it is added rotational mass that you do not need.

Can I set up a non-tubeless wheelset as tubeless?

A wheelset that has not been designed to be used with a tubeless tyre system should not even be considered for a tubeless setup. The simple reason is that the rim has not been designed for the needs of a tubeless system. If you are in any doubt whether the wheelset is or isn’t tubeless compatible it is always best to err on the side of caution and use an inner tube.

As far as brake performance is concerned with carbon wheels especially, the main thing is to make sure that you are using the correct brake pads for the wheels that you have. If you are concerned about the life of a carbon rim due to braking, keeping your pads clean and free of grit or contaminants will make sure you don’t prematurely abrade the rim surface.

What are the criteria for a good sealant, how do they work and are they worth it?

There is a lot to unpack with this question. Tubeless sealants are typically latex-based with some sort of coagulating particles within them. As the sealant is forced through the puncture hole with the rushing air it dries and plugs the hole. What really differentiates tubeless sealant performance is the types of particles used. Some brands use a variety of different-sized particles which better aid the plugging and drying process.

One of the downsides of a premium sealant that has these plugging particles in it is that they typically cannot be injected through the valve core. Instead, the sealant needs to be poured directly into the tyre itself before it is fully fitted. This is because the particles can be so good at plugging holes that they will clog up the valve core and make inflating your tyres almost impossible.

If you have any tech-related questions that you need answering, head over to this week’s Tech Clinic video on the GCN Tech YouTube channel and add your question to the comments along with #ASKGCNTECH. Or leave your question in the comments below.

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