sportridertex

When I bought my Dawes Galaxy new in 1969, it had gumwall tires, what is gumwall exactly?

I have my 1986/7 Schwinn Traveler, and now I have black Specialized Tri-Sport tires it

arctangent

Yellow tire walls.

Ivandarken

It doesn't matter... you are going to sell me the Galaxy...YOU ARE GOING TO SELL ME THE GALAXY...YOU ARE GOING TO SELL ME...

bernardmarx

Carbon black is added to harden rubber - the normal color of rubber is pale to tan. The softer sidewall compound is supposed to decrease rolling resistance. It is, however, more vulnerable to damage from ozone pollution.

Ivandarken

That is true. So leaving your bike for years in the basement with the furnace and water heaters can make them break down and look terrible. This is internet hearsay. I don't know the science.

tatfiend 

Per Frank Berto in his 1988 book on upgrading road bikes, he differentiated gumwall from skinwall tires by the amount of rubber on the sidewalls. Skinwalls were high end road tires with minimal rubber on the sidewall and usually you could see the casing fibers through the rubber. Gumwalls were cheaper and heavier tires.

Gumwalls used thicker rubber on the sidewalls and were lower performance, and less expensive, tires. This was regardless of sidewall color. From what I have seen probably still true today. Most of the high puncture resistance tires and cheap tires would be considered gumwall construction while light weight performance oriented tures would be considered skinwall tires.

sportridertex

I wish I still had it,,,,,,,

Ivandarken

Doh!

zebede

My juinor college engineering instructor worked on PT boats during WW2. He told us of a rather difficult problem he had to resolve of why the rubber based wire insulation in one of the compartments would rapicly break down causing all kinds of erratic problems. After much research it was determined to be ozone (0sub3) which was formed from oxygen in the air passng over an electric arc. The cure was to ventilate. FWIW he told me he worked on JFKs boat.

Much later I worked at a facility that produced ozone for disenfection. They first distilled oxygen from the air and then passed it through an electric arc to produce ozone. O3 is short lived and rapidly decomposes to O2.

Is this what is happening in a basement with gumwalls - I don't know. However I would not put an ozone generator in my basement. They sale these things for the home for odor control.

USAZorro

Exactly correct. At a distance, gumwall and skinwalls look pretty much alike. There's a world of difference in weight, ride quality, and road feel between the two.

Chombi

+1 on the harmful effects of ozone damage on tires.
Some years ago, my Honda Hawk GT mororcyle's tires suffered from accelerated dry rot after just a little bit over a year parked next to our apartment building's mechanical room that had all sorts of big electric motors running in it all day long with their brushes producing lots of ozone. I knew that the damage was from the mechanical room ozone because only the side of the motorcycle that was always faced towards the door louvers to the room had ost of the rot damage. Bad thing was, the damage ususally creeps up on you and you susually notice things like this when it's too late. Had to replace both perished tires (but still with a lot of good tread left) on the bike to keep it safe.

Chombi

velo-orange

Does it bother anyone else that 'skinwall' is used to describe not only the amount of gum rubber on tire sidewalls, but also refers to the color of the tire? 'Blackwall' is black, 'skinwall' is- non black.
Last time I checked, skin color has a range of hues.

Barrettscv 

Yeah, I would avoid using "skinwall".

Older readers like me might not question the use of the term, but younger people could find the term to be incorrect or meaningless.

mkeller234

I dont think skinwall is a confusing term... to me it just means less rubber on the sides. If I saw skinwall tires that were red, I would probably say red skinwall.