January 17th 17, 03:48 PM
posted to rec.bicycles.tech
external usenet poster
Stronger rubber cement?
On Monday, January 16, 2017 at 11:38:15 PM UTC-8, John B. wrote:
On Mon, 16 Jan 2017 21:51:38 -0800, Jeff Liebermann
On Mon, 16 Jan 2017 23:05:43 -0000 (UTC), Duane
The idea of two pounds worth of tubes to avoid putting air in my tires
doesn't parse at all.
Let's do it by the numbers.
The tubes I usually buy are these:
26x1.5" for $4.79ea. They weigh 176g (0.39 lbs) and they leak air.
The proposed leak proof tubes:
26x1.5" for $15.36ea. These weigh 572g (1.26 lbs).
For two tires, that a difference of:
2 * (1.26 - 0.39) = 1.74 lbs (789g)
Not quite 2 lbs but close enough.
The average 26x1.5" tire
seems to weigh about 550g (1.2 lbs). Ignoring the weight of the
wheel, with these tubes the rotating weight will increase by:
1.74 / (2 * (1.2 + 0.39)) = 55%
Offhand, it seems a bit too heavy to be worthwhile.
Please note that my original problem was not to find the best thorn
proof tire, but rather one that doesn't leak out of the box. I don't
seem to experience any sudden releases of air, but instead get slow
leaks. On the wheels in question, I ride on pavement.
Inner tubes come in a myriad types and prices. If you buy the absolute
lightest, thinnest, tubes, they will leak, but if you buy thicker
inner tubes they will usually be cheaper and may leak a bit but not to
the "pump them up every day" extent.
It used to be that "sew ups", or "tubular's", were the last word in
bicycle tires and, as I remember it, they did require pumping up
practically every time you got on the bike. (and I don't remember
anyone complaining about it :-)
Tubulars are still the last word in bicycle tires and what the pros ride, but they have professional support staff who are physically fit and skilled in the complex operation of floor pumps and other precision machinery. Most of us do not have the intelligence or fitness necessary to operate a floor pump -- and certainly not on a daily basis. My wife and I have more robust tires on our bike that we have professionally pumped once a year. http://www.loupiote.com/photos_m/796...re-bicycle.jpg
-- Jay Beattie.