Posts tagged #Tubes

To Powder or Not to Powder...

          

A recent post on inner tubes "Latex v Butyl" has created interest in another of those topics which can stir passionate debate, whether to use talcum powder on inner tubes. So I shall offer my views on the subject and you can make your own decision.
           I shall state from the outset that I do not usually use powder when installing tubes. That being said I have customers that do and I have a canister of 'Johnson's' in the cupboard so, if requested, I can powder up a tube to keep everyone happy.
           Firstly, what are the reasons behind some people’s choice of using powder? Well, powder can make the tube easier to glide around against the tire when you are trying to wedge everything together. I know many people have trouble when trying to poke a tube into the tire and pinching the tube under the bead of the tire is a common problem for some. Also, when removing a tube from a tire, it is easier when dealing with a tube that was powdered. I have also heard the argument that when a tube is powdered there is less friction between tube and tire and less likelihood of failure from abrasion. Finally people see that there is often some trace amounts of powder when you get a new tube out of the box so therefore powder must be good.
            Okay, I think that covers most of the arguments that commonly get mentioned for the use of powder, now for my rebuttal.
            Starting from the bottom of the list, the reason manufacturers use powder is actually during the manufacturing process itself, it is not as some suggest them pre-powdering the tube for you. When the tubes are made the rubber becomes very hot, even by the time the process is over there is still considerable heat left. The powder is actually used on the inside of the tube so that when the tube is folded flat and pressed into the packaging the two sides of the tube will not bond together. Next time you have an old tube at hand cut through it and you will see a fine white powder coating the inside.
            Friction. I have never quite got my mind around this one. If anything you are creating a scenario to create more friction by using powder. When a tube is correctly inflated inside of a tire there really is no room for any movement between touching surfaces. Also we have all seen how a tube bonds slightly to the tire, if there was a need for any movement it would be very slight and the tube would be much better flexing instead of sliding against the surface as the powder argument suggests. And before the cries of tubes completely bonded to tires rises to crescendo, this never happens to the extent of tossing a tire away because of a tube that cannot be removed. I have replaced more tubes in my life than I have eaten hot dinners and never have I had a tube that refused to “Part Company” with anything more than a sharp tug. In fact that slight bonding helps out in another way too. When a puncture does occur, due to an errant thorn or some such, having the tube attached to the tire means that the air only comes out through the hole at that spot around the thorn, if you powder the tube and there is no bonding the air will escape from the tube into the cavity and be gone much quicker.
             Lastly, the installation. Here at least I do see a benefit for those who struggle with tube replacements. However, if you follow a set of rules such as, inflating the tube enough to give it body, make sure to get it seated up into the tire before popping the final bead on and never sticking tire irons in there, you should be fine. Most issues come when popping the last 6 inches of bead on and no amount of talc is going to help you there.

Posted on October 20, 2012 .

Butyl versus Latex. The Great Debate



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.
Posted on October 15, 2012 .

Tire Sealant, Our Recommendations.


       Tire sealant has been around for a good many years now and has certainly improved greatly in that time. What started as a thick sludge suitable only for a lawn tractors or wheelbarrows has now progressed to a foaming lightweight liquid suitable for a race wheel tubular. When I was mountain biking regularly in England I had great success avoiding punctures by using a bottle of the green slime in each tube. When the tires wore out and were removed from the rims there had been so many punctures sealed that the tubes had welded themselves to the tires, made me a fan of the stuff for life. It is still sold today and is still Martian green and still works great in a tube setup.
        Basically all the sealants work in the same way. When the casing is breached air rushes out through the hole taking the sealant with it, as the sealant flows through the hole, particles in its formula seal the gap. Although the principle is the same throughout the range of products on the market we have found some of these potions are more successful than others at getting the job done.
        For a comfort on hybrid bike or even a fat tire mountain bike running regular tubes Slime is still hard to beat. It is easy to install in a Schrader tube and, with a little patience and a removable valve core, it can be used on skinny valves too. Although it can be put in road tubes I find that it does not work quite as well under high pressure. Although Slime is about the beat of the bunch when using a tube, making the switch to a tubeless system can offer up a whole new set of possibilities.
       When using a tubeless system, such as the one offered by Velocity or the similar Stan's method, we prefer to use the Cafe Latex brand of sealant and the Stan's sealant. When putting a tubeless mountain setup together we prefer the Stan's sealant. This stuff works great on big tires, it seals quickly almost any puncture from thorns to nails and helps seal any areas around the valve and along the beads. It will not seal a cut or slit, none of the brands will, and like other makes, it does lose its effectiveness over time. Any punctures sealed stay sealed but after around 3 months the mixture dries up considerably and ceases to work sealing new holes and needs replacing.
      When it comes to tubeless road systems we prefer the Cafe Latex brand. This stuff is great on high pressure skinnies and seals quickly and permanently any punctures. Like the Stan's it also helps seal values and beads however we do find that it tends to keep its effectiveness a little longer.
Posted on August 29, 2012 .

New Tubes From Michelin.

          The good folks at Michelin recently added a new tube to the line-up and this is not just another round piece of rubber but a completely new, very profiled design with a square shape to the top and raised sections. It is designed, apparently, so that instead of the rubber being pulled apart it is compressed. This makes a big difference in the event of a puncture, the pressure works with the tube to help seal the hole. Add some sealant to the design and you are good to go, in theory. In practice I have not had much feedback yet but it sounds like a good idea for a trail tube to me.
          Check out the video for a more detailed explanation.


Posted on August 13, 2012 .

It's Hot Enough To...

The other day we received a call from a couple on the trail, about 5 miles east of Jefferson City. They were suffering from a serious attack of flats and finally a split tire. Through the wonders of Google and an I Phone they came to us.
       10 minutes later I am in the pickup heading over the river. Now I don't mean to whine but, it seems the only time I get called out is when the temperature is about 30 degrees above or below my comfort zone. Today's temp of 105 put it quite handsomely in the above category.
       Luckily they were in the open and easily spotted, unluckily they were in the open and I was about to get cooked. By the second handshake my eyeballs are sweating and I'm eager to get started. Without further ado the problem bike is flipped over and I'm pulling wheels.
       Now I'm not new at this tire changing thing and, whilst I'm not professing to being the faster tire changer in the west, I ain't the slowest either and my thumbs have pushed so many errant tires onto rims they have developed callouses. So you can imagine my surprise when, after pushing the front tire on, my hands and, especially my thumbs, are not just sore but downright painful.
        The rims were so hot both thumbs had developed large blisters. By the finish of the rear tire and tube change the skin had all but gone on one.
        Anyway, the job got done and the couple was very happy, although being happy in 105 degrees did make me question their sanity somewhat, but it takes all sorts. By the time I got home I figured I'd need a skin graft and a week off, Pam settled on a small band aid and told me to get back to work.
        So, here's the thing. I brought the old tires and tubes back to dispose of them and, on closer inspection those tubes suffered in the heat. The rubber definitely felt different and the valve stem needed next to no encouragement to eject itself. In this triple digit heat of late and bikes being left inside cars we have had quite a run on tubes. So try and be careful when leaving bikes in the heat. Maybe let some pressure out of the tires and be careful when removing the pump head after inflating them.
        Now, excuse me while I go and soak my thumbs...
Posted on July 29, 2012 .