View Single Post
Old 04-16-2010, 04:48 PM
mabman mabman is offline
Motorized Bicycle Elite Member
Join Date: Oct 2008
Location: In the wind
Posts: 258
Default Motorized Bicycle Specific Tire

I am in close contact with a principal of a bicycle component manufacturer. They would like to build a tire for the motored bike community, but because there are so many different tire diameter/sizes to choose from I felt that coming here to see what you all think is needed and why and if we are on the right track.

To get anything done at this level there will be only one tire to start so the idea is to make the one that will work for the broadest spectrum of the current motored bikes on the road today.

There are three ways that they build up tires. One is to just use the casing which is comprised of two thin layers that encapsulate the beads. This is the lightest way to build a tire but also the least reliable in the long term. This is the way most of the tires are made that you get cheap at the store and many of you ride on your bikes.

The second way is to add a protective layer under the casing from edge to edge of the tread applied between the casings that will protect the tread area better, but still has a single layer sidewall and is somewhat heavier and costs a bit more for the extra materials and labor but is worth it to many for the extra protection that it provides.

The third way is to run the same protective material from bead to bead bedded as the former in another layer so that you not only get protection from the tread area but also the sidewalls are protected and instead of single thickness they are 3 layers. This type of tire is used by the DH MTB crowd currently in knobby versions galore and is heavier yet and a bit more costly. But once again the protection that it provides is what some people need and so that is why they exist. Here is an example:

In looking at the above three options it is pretty obvious that the 3rd one is a good starting point for the casing. The tread is a whole different aspect of tire manufacturing and any tread can be put on any casing that meets its sizing criteria. For motored bikes it seems most ride primarily on the street so basically a street type tread will be applied to a downhill casing tire. Should be pretty beefy. But at some point in the near future we will be perhaps facing DOT compliance and is it going to be enough?

Another way to make a tire stronger is to make it tubeless ready or even UST which is very popular in the bicycle industry now and after 5 or so years of use the tubeless bicycle tire is here to stay. But in order to run tubeless reliably you need a TRS or UST tire. Rims are also a help with the tubeless system but there are what they call "ghetto" ways to make just about any rim work with a tubeless type tire. Here is a good way to see this happen. YouTube - Broadcast Yourself.

I guess the reason the auto industry went to tubeless years ago was because it worked well and that is also what the bike industry has discovered. It was kind of hit or miss at first but now it is very reliable and had some distinct advantages over running tubes. The first is that the sealant added is latex based and not as nasty as Slime to deal with but does the same thing by closing punctures off before you lose much tire pressure. But Slime won't seal a bead and the latex will so that is another advantage. Because you are eliminating the tube, but not the ability to run one if the need arises, the thicker wall tire will be more supple without the inner tube layer pressing against the casing. Arguably there is a weight savings but that is not as important for mab's in general as durability is. Anyway here is a pic of how the industry is set up for tubeless.

The last part of the tire puzzle is the tread pattern itself. The tread is applied in a mould under pressure and bonds itself to the casing. This is an example of a tread pattern that has a mould already and is being recommended by the designer as a good all around street tire that will handle some dirt also.
Graffiti from WTB.jpg

And here is another from the same company.

There are similarities between the two that along with that of the currently popular Schwalbe Marathon leads one to believe that pattern works well for street and some dirt use because contact patch is key in those environments.

Something you will notice about the Schwalbe is that it fits in to the 2nd category of the casing examples above which provides good protection to the tread area but nothing extra in the sidewall area which is the right way to do it for regular bikes. But the extra weight and speed of motored bikes should be better served by the #3 option?

In regards to size it seems like a 26x2.125 would work the best for this? Not wide enough to interfere with chain line but enough for decent volume for some extra cush. The second tire would be a 2.5 version and that is the one I am waiting for but have to go through the one to achieve the other as odd as that sounds?

Feel free to provide any input you may have to share about this and the sooner it will happen.

"The future is already here, it is just not evenly distributed"

Last edited by mabman; 04-16-2010 at 04:54 PM.
Reply With Quote