GCN Tech Clinic: Tubeless spares, wireless brakes and heavy tyres

This week Ollie Bridgewood and Alex Paton are back to take a look at some of your tech questions to offer the answers and advice you need to keep you enjoying riding your bike in fine working order.

What spares do I need for tubeless?

Tubeless systems are great. They prevent those annoying pinch flats when you hit that pothole you didn’t spot, as well as working magic for plugging holes in the tyre from thorns or road debris. This being said, they are not completely puncture-proof and in the event of a puncture that even the tubeless system cannot seal, there are a couple of things you need to carry.

For starters, a good pump or CO2 inflator will come in handy, for times when you need a large volume of air quickly to get a tyre to reseat on the rim. A CO2 inflator will do this better than a mini pump. Another thing to carry is a tubeless plug tool, but make sure you know how it works before you need to use it. This can help with any holes that are too big for sealant alone to fix. In case of a total system failure, an inner tube and self-adhesive patches should be carried as well as some tyre levers.

Carrying this kit will get you out of almost any puncture situation whether that is with a tubeless system intact or running a tube as a backup.

Do the pros use inserts?

It's not a blanket answer, but yes some pros do use inserts for certain races. For those that are unsure as to what an insert is, it is a foam ring that goes inside the tyre to offer a run flat property if a puncture does happen on a tubeless system as well as protecting the rim if that were to impact something like a cobblestone.

Is anyone working on wireless brakes?

This is a natural question to ponder on; we have wireless shifting so why wouldn’t the logical next step be to include wireless brakes as well? Some companies have dabbled with the idea, and we've seen a few prototypes popping up, however there is no real chance that wireless brakes will ever be something we can buy.

The issue with wireless brakes is that there is no physical hard-wired connection between the lever and the brake, so in the event of a battery dying or a connection failing you would be riding a bike with no brakes. If this were to happen on a shifting system, there is no real safety concern; it can be annoying for the rider but ultimately it will not cause any harm.

Wireless brakes are something that just are not worth the risk for riders or manufacturers, and really there is nothing wrong with a good hydraulic disc brake system.

How do you clean a bike with a waxed chain?

If you want to give your bike a real deep clean, it is probably best advised that the chain is removed from the bike to prevent any degreasers or cleaning products from removing the wax coating on the chain.

If you are just doing a general clean to keep on top of things the chain can be left on the bike however you should avoid cleaning it with any products or water.

When the chain is dry, use a clean microfibre cloth to run the chain through, this will remove any surface contaminants and dust as well as give you a chance to inspect the chain to see if any more drip-on wax is needed.

Will we see a change in how climbing bikes are marketed?

With aero bikes being marketed more and more based on facts and figures on how much time they will save you at a certain speed for a certain distance the logical extension of this would be to see the trend extend to climbing bikes too, right?

Due to the nature of climbing, it is far harder to quote these facts and figures as there are too many variables to offer anything meaningful. Due to total system weights having a large effect on the savings of a climbing bike, it makes giving exact savings almost impossible. It is for this reason why climbing bikes are still typically marketed based on how lightweight they are rather than as an expression of efficiency.

Can I run GRX Di2 and Ultegra Di2 together?

The short answer to this one is yes. To be double sure for the specifics of your configuration, Shimano has a handy compatibility chart on their website that details what can and cannot be used together.

The most important deciding factor on whether they will work together is if they have matching etube cables and if the generations are compatible, for example running 11-speed GRX with 11-speed Ultegra rather than trying to mix groupsets and generations as this will not work.

Could heavy tyres be faster?

The principle behind this question is using the tyres increased mass as a flywheel that once up to speed will have more inertia that will help maintain speed. For very steady state efforts where you are riding at a fixed speed, there may be some truth in a heavier tyre being faster.

There are however a lot of drawbacks to using a heavier tyre as this is what is known as a rotating mass. A heavier tyre is going to take a lot more energy to get up to speed, as you are trying to spin a heavier mass, this means that if you ride somewhere that requires lots of acceleration out of corners a heavy tyre is going to cost a lot of energy.

The same also applies for braking as well. Because you get that flywheel effect from a heavier tyre, it will take a lot more input on the brakes to slow down. A heavy tyre’s inertia will fight the braking force as it tries to maintain its speed. Once again, if you ride somewhere with lots of descending or corners a heavy tyre is not going to be advantageous.

Although there are some isolated situations where on paper a heavy tyre could offer a slight performance benefit, the negatives greatly outweigh the advantages of this and we'd say you're better off looking to select a lighter tyre that accommodates your riding needs.

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.