Every year, as sure as leaves turn and fall, the perennial debate of "what are better butyl or latex tubes?" rears its head in the store. This year is no exception, brought to life by a group of riders traveling across the country and looking for a mediator. Now I have learnt long ago when to keep my head down and look busy and this was one of those times. The rest of their trip gives me a headache just thinking of it. Anyway I thought that I might offer my thoughts on the subject here, where it is quiet…
Firstly a little history, back in the day, the only game in town was latex rubber, basically latex is the stuff you pull out of trees and plants that can be formed into a rubber. Most plants exude some form of latex when they are cut or injured in some way. One tree in particular ‘Hevea brasiliensis’ was found to have great potential for commercially made latex rubber. Now I am no chemist so I will cut the lesson short on manufacturing natural latex, suffice to say it is produced from trees. I should say that natural latex is, as it can be synthetically manufactured as well but originally everything from gloves to tires to condoms were made of natural plant based latex. Now everything was progressing fine until the advent of WWII. Amid worries about supply of rubber for everything from tire tubes to condoms a push was made for a substitute. Along came butyl, proper name Isobutylene Isoprene Rubber. The basis for this compound was developed by the German company BASF in the early thirties but was developed into what we know as butyl today by a couple of guys at Standard oil just before the onset of the war. Anyway I think that covers the how and the why but what is the difference and benefits of the 2 when it comes to your bike.
I will agree that there are benefits to a latex inner tube and paired with a suitable tire they can be felt by most competent riders. The benefit comes in the form of better rolling resistance due to better or faster elasticity. When rolling, the tube is compressed and then, as it rolls along it springs back to its original profile. At the contact point the tire has a portion of its profile squashed to the road, obviously tire pressure and profile all factor in but as it is rolling the section that is leaving contact has to bounce back, the quicker this happens the less contact patch there is and by default the less drag. Latex is like a huge tight spring and it snaps back quickly. Butyl on the other hand acts like a hydraulic shock and bounces back slowly and in a controlled way, the energy is absorbed along with the heat.
Other benefits include better feel when generally riding, for the reasons mentioned above, the tube also benefits cornering and basic feel.
A few things to consider when running Latex tubes.
· Compared to butyl air leeches out quicker from a latex tube. Get used to pumping them up before the event to ensure proper psi.
· Because of the high permeation rate, as mentioned above, do not use CO2 to inflate them. CO2 permeates through latex much quicker than regular air which is predominantly nitrogen.
· They are lighter than a regular butyl tube, although some of the ultra-lite butyl are comparable. I have never been a big fan of the ultra-lite butyl tubes, they are extremely flimsy and the failure rate on them is very high which in my opinion negates any gain, especially on race day. Latex tubes in comparison, despite their delicate nature are surprisingly durable. They will shrug off lots of abuse. They will find any weaknesses in your rim tape though so be careful to install good tape well.
|A standard Latex tube.|
A latex tube will be beneficial to any good road race tire to a certain degree. That gain can vary from about 1.2 watts to about 2.8watts. Using a supple, high thread count tire makes a big difference. On tires utilizing some form of protective aramid belt or a thicker rubber tread the benefit will be considerably less.
Over the years latex has been definitely pushed under a rock when it comes to bicycle inner tubes and, honestly, that is probably the best for most riders. Butyl is much more suitable to the needs of most cyclists. It is thick and offers a little more protection and durability than latex. Butyl holds air better, it still needs topping off regularly but compared to latex it is significantly less permeable.
Latex still has a place though, for those riders looking for ultimate performance from body and machine latex tubes can be a benefit. At this level any performance gain is always minimal but it is there. Running a quality latex tube in a quality race tire on race day is another of those gains.