Boxerworks.com

Jean wrote:NOW we can debate what exactly "tube-type" rims really ARE!!
Were they solid rims before the DOT decided there needed to be safety beads near the outer edge,
or only rims with BOTH beads to prevent tires going to the center, or just what?...

vanzen@rockerboxer.com wrote: ... The difference between a WM2 (tube-type) and MT (tubeless) ?
Just inboard of the vertical part which holds the bead and sidewall of a tire
(virtually identical on WM2, MT, and MTH2 rims)
a WM2 will be horizontal, but an MT will have 5º of upward angle.
This will be the NHTSA / D.O.T. mandated design change intended to hold the tubeless tire onto the rim.
In addition to this 5º angle change, later MTH2 (tubeless) rims also had a "bump" or "bead" just before the drop center
to prevent the tire from dropping to the center of the rim.

Jean wrote:I think you have missed the sarcasim in my comments.
I also drive a Corvair...in addition to obviously obsolute, deadly motorcycles.

Ken in Oklahoma wrote:It would seem that a tubed tire has to run hotter than the same tire run tubeless. Stipulating that the heat is generated by the tire side wall flexing (with a possible addition from the tread flexing, i.e. the tube not actually generating the heat by itself) then the addition of a tube still will hinder the heat transfer to the inside of the wheel. It is, in effect, an insulating layer. If one asks where can that heat go once on the inside of the tire/wheel, I would say that the rim, whether steel or aluminum (or magnesium) would be a significant heat sink.

Ken

Native /5 wrote: The tube is not between the tire and its contact with the rim. I don't understand how it will impede heat transfer between the tire and rim. I can see heat being transferred to the tube and thence to the rim from the tube, thereby increasing the rate of heat transfer with its larger contact area on the rim.

Roy Gavin wrote:The tubeless tire in question had the notation on the side - "On tube type rims use a tube."
There was no mention of reduced speed rating.

Given that providing the speed rating on a tire is a mandatory requirement if fitting the tube reduced the speed rating then it would be mandatory to provide both ratings , but I have never seen a tire marked that way..

My recollection is that the the no tube ,err,theory originated when radial tires were introduced - the theory was that the flexible side walls would rub against the tube and heat the tube.

Over the years the story seems to have migrated to all tires, but I have never seen anything authoritative to back it up, and as I said, actual experimentation proves it doesn't happen, at least not with extra heavy thick tubes, and it would appear not with the tires that Metzler test and sell.

Native /5 wrote:

Ken in Oklahoma wrote:It would seem that a tubed tire has to run hotter than the same tire run tubeless. Stipulating that the heat is generated by the tire side wall flexing (with a possible addition from the tread flexing, i.e. the tube not actually generating the heat by itself) then the addition of a tube still will hinder the heat transfer to the inside of the wheel. It is, in effect, an insulating layer. If one asks where can that heat go once on the inside of the tire/wheel, I would say that the rim, whether steel or aluminum (or magnesium) would be a significant heat sink.

The tube is not between the tire and its contact with the rim. I don't understand how it will impede heat transfer between the tire and rim. I can see heat being transferred to the tube and thence to the rim from the tube, thereby increasing the rate of heat transfer with its larger contact area on the rim.