GCN Tech Clinic: Patching TPU tubes, cornering speed and bib shorts

Your questions about groupset compatibility, TPU tubes, and cornering answered by Alex Paton and Si Richardson

Clock10:04, Thursday 2nd November 2023

Joining Alex Paton this week in the tech clinic is Simon Richardson. They're pooling their collective knowledge to answer any questions and queries you have regarding your riding and bike. From component compatibility through to getting the most out of yourself as a rider, the guys are here to help.

Can you mix components from different tier groupsets?

As long as you stay within the same brand and speed that you are replacing, mixing components across a brand's hierarchy is fine. Not only is it acceptable, but it is also a great way to save some money when it comes to replacing components as they wear out. Often for items like chainrings and cassettes, the main penalty is weight. Swapping from Shimano Ultegra to 105 for example won't cause any issues, in fact it's something we've done multiple times.

Is it possible to repair a TPU inner tube?

When TPU inner tubes were first released to the market one of the main gripes was that they weren't repairable. This was understandable, especially after paying a high price tag for what is a premium product. Luckily things have now changed and you can patch up and repair TPU inner tubes.

Essentially it's very similar to repairing a typical butyl inner tube, however instead of roughing the area up before fitting the repair patch you wipe it over with an alcohol wipe. Once the area is clean you can then fit a specific TPU patch with the corresponding contact adhesive.

What is the best all-round configuration of wheels and framesets?

There is a lot of choice out there when it comes to selecting the right bike for you. There are climbing bikes, aero bikes, endurance bikes, and bikes that seemingly bridge them all. On top of that, you have lightweight wheels, aero wheels, and all the types of wheels in between. But what configuration is actually the best for all-round performance?

Alex thinks it's best to go fully aero with an aero frame and aero wheelset. The weight penalty for aero kit is relatively small, especially when considered in the context of the weight of the rider. Aero benefits can still be experienced at relatively low speeds with tangible benefits on offer for most people. Unless you live in an area with long and steep climbs an aero bike is probably going to be the choice for you.

Can you apply a drip-on wax lube without degreasing the chain first?

The short answer to this is no. By the very nature of how a wax lube works, it needs to have complete contact with the links and rollers on the chain. If you leave the original grease on the chain and just apply the wax on top of this, it will never be in contact with the chain itself. This means it won't be acting as an effective lubricant but it will also come off very easily.

The best thing you can do is to give a new chain one really good degrease before applying the wax. This way you know that it is going to have the correct treatment to allow maximum adhesion to the chain and provide you the benefits that wax can offer.

What is the difference between a budget and a premium bib short?

This can be a confusing topic and it can depend on who you ask as to the answer. As a general rule the more you spend on a pair of bib shorts, the more technology will have been used in their design and manufacture. So a more expensive bib short will have a higher-tech fabric that can be more aerodynamic or better at helping to regulate your temperature. You'll also get a higher quality chamois pad that offers more in the way of anti-microbial protection and comfort.

The most important thing when selecting a new set of bib shorts is that they fit you well, regardless of the cost. There's no point in buying a premium pair of shorts only to find that they give you saddle sores or the straps don't sit well on your body. There is, however, a point when you reach a state of ever-diminishing returns – where spending more doesn’t really get you all that much more in terms of performance. So finding something comfortable is the best place to start.

Read more: Why you should invest in cycling bib shorts

How fast should I be able to go around a corner?

The answer to this is wrapped up in so many variables that it is impossible to give an exact answer. Not only do the tyres you use and your body weight play an important role but so too does the road surface, your tyre pressure, temperature and your body position.

The best way of finding how fast you can go around corners is through practise. As you practise your body learns how the bike feels at different speeds. Over time you'll begin to develop a sixth sense for how quickly you feel you can take a corner relevant to those conditions we mentioned before. One of the best ways to improve your cornering is to follow someone who has a bit more experience. They can tow you into corners at a higher speed and you'll be able to follow their line.

For more information on cornering, why not check out our very own documentary on GCN+ where we take a deep dive into the science of cornering.

How does a waxed chain hold up in British gravel conditions (mud)?

A waxed chain will suffer more in wet and muddy conditions, this is because the water paired with the grit and grime that will inevitably coat your drive train will wear down the wax coating.

On a recent coast-to-coast gravel ride that Alex and Si completed they used different methods of chain lubrication for the ride. Alex had opted for an immersion wax coating whereas Si had chosen to stick with a traditional wet lube. At the end of the ride, the waxed chain was almost bare of wax and needed to be re-treated. Si’s chain also required a complete degrease to clean it of all the mud and dirt that had accumulated over the ride.

Although the process of waxing a chain might be slightly more involved than a traditional lube, you are going to need to tend to the chain at similar intervals regardless.

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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