Why TPU for bicycle Inner tubes
A comprehensive guide comparing TPU (Thermoplastic Polyurethane) and standard butyl rubber inner tubes. This guide will delve deeper into each material’s performance in terms of rolling resistance, air retention, weight, and more!
While it’s not a noticeable bike component (not until you have a flat tire), a bike’s inner tube plays a significant role in its overall performance. There’s a lot that goes into choosing the right bike inner tube, even if you’re riding a bike with a tubeless tire, you want to ensure that you have the best spare inner tube in case you get a flat tire which don’t fix with sealant.
Butyl rubber inner tubes
Butyl rubber is the most common type of inner tube used by bikers. Butyl rubber inner tubes are most common and readily available than other inner tube types.
Butyl rubber inner tubes are also durable and have a good air retention rate, meaning they hold in air for longer periods, so you don’t have to inflate your tires often.
What’s more, they can be repaired. If you have a puncture, you can patch up your butyl rubber inner tube using a standard puncture repair kit sold in every bike shop.
However, butyl inner tubes are heavy, creating more rolling resistance affecting your bike’s overall speed.
TPU (Thermoplastic Polyurethane) inner tubes
TPU inner tubes made their way into the inner tube market the last 10 years, and they have won over many riders quite quickly. Known for being lightweight, TPU has become a preferred inner tube option, for bikers keen on performance such as rolling resistance, acceleration, and weight.
TPU inner tubes are highly elastic, which not only reduces rolling resistance but also increases its puncture resistance. What’s more, it also has impressive air retention despite its light weight and can be packed incredibly small as when carried as spare tube. Naturally TPU inner tubes can be patched up in the event of a tire puncture with a specific repair kit that are also sold bike shops.
However, this inner tube type is a bit more costly, but bikers argue that the price is compensated by its reduction in rolling resistance and weight, which is vital for riders keen on their bike’s overall weight and speed.
With that being said, here’s a detailed performance comparison between butyl rubber and TPU inner tubes.
Weight
The main difference between butyl rubber and TPU bike inner tubes is their weight. TPU inner tubes are incredibly lightweight, weighing as low as 20g (Eclipse Ultra tubes).
On the other hand, comparable butyl rubber inner tubes weigh approximately 100g, which is 3 times the weight of an average TPU inner tubes. Now, this mean a lot, if you are focused on your bicycle’s weight and the wheels’ rotational weight.
Rolling Resistance
Speed is a significant factor regarding your bike performance, rolling resistance is something you ought to want to look at. When it comes to rolling resistance, less friction results in less energy loss when the tires are rolling (rolling resistance), and the faster you ride.
An important detail affecting rolling resistance of tires is the inner tube. TPU inner tubes absorb less energy while rolling than butyl ones, meaning they have a lower rolling resistance, which ultimately increases your riding speed.
Air Retention
When it comes to air retention, TPU inner tubes have an excellent air retention, impressive considering how thin and lightweight they are.
Reparability
Butyl rubber and TPU inner tubes can be repaired in the event of a flat tire. Butyl rubber inner tubes can be patched up using a standard puncture repair kit while TPU inner tubes can be repaired using a specific TPU repair kit, both are available in bike shops.
Cost
TPU inner tubes are more costly than butyl tubes, yet compared with other performance set ups, like tubeless tires the cost is even lower if you look at all involved parts like tire, tube, valve, rim tape and sealant. On top a tire + TPU tubes have in general lower total weight than tubeless tires.
Puncture Resistance
TPU inner tubes are highly puncture-resistant due to their high elasticity and material strength compared to butyl rubber ones, on the other hand.
Environmental Impact
TPU inner tubes use just one raw material when being manufactured, unlike butyl rubber ones. Both inner tubes are sustainable since they can be recycled. However, TPU inner tubes can be 100% recycled into raw material for making other TPU inner tubes, while butyl rubber is mostly downcycled to carbon black and process oil with lower properties.
So why TPU Inner Tubes?
While butyl rubber inner tubes are more affordable, TPU inner tubes offer the “entire package” for riders who look for performance of their bicycles, making their price tag reasonable. If you want to enjoy lighter weight, low rolling resistance, high elasticity, puncture, and air resistance, then TPU is an excellent inner tube choice for your bicycle.
Blog post by Olivia Kosiro