Gumwall Tire Question

Discuss light weight issues concerning road bikes & parts.
CAAD8FRED
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by CAAD8FRED

Hello all

What wheels can gumwall tires work on without getting cut up and which ones can they not work on. Is it TLR wheels that cut up gumwalls?

TobinHatesYou
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by TobinHatesYou

CAAD8FRED wrote:
Mon Oct 07, 2019 3:05 am

Is it TLR wheels that cut up gumwalls?

No.

Anyway it depends on the model of "open tubular" about as much as it depends on the specific rim. You might be able to find comfort in tires made for brands that have their own wheels/rims. Bontrager R4 320, Specialized Turbo Cotton, etc.

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Calnago
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by Calnago

It’s really got nothing to do with whether the tire is “gumwall” (tan in color), or black. It’s about
1)whether the rim has a sharp edged bead edge or not, and this is a lot more common with carbon clinchers versus alloy, be they tubeless or otherwise, and...
2) how susceptible the sidewall of the tire is to cutting. If it’s got a super thick casing, it’s likely to resist cuts but probably isn’t a very nice tire to ride. If it’s got a thin supple casing, it’s probably nice to ride but more prone to being cut by a sharp edge.
The best handling and nicest riding tires have pretty supple sidewalls. A quality tubular has such sidewalls enclosing a latex tube (generally) and has the best ride quality and doesn’t have to worry about being cut up by the bead of a carbon clincher. An “Open Tubular”, which is simply marketing speak for the best clinchers in an attempt to associate the qualities of a tubular with a clincher, are still clinchers, and as such are susceptible to getting cut by a sharp bead edge. Doesn’t have to be an “open tubular” and it doesn’t have to even be a carbon rim. Just happens that the most likely scenario for that happens with a thin supple casing against a sharp carbon edge. I’m sure you’ve seen the debacle ENVE has gotten themselves into with some of their rims. Although the issue isn’t limited to ENVE, it’s still an issue, and several manufacturers warn against using their clinchers on carbon rims in general. So use common sense when deciding on a tire/rim combo. Feel the edge of your carbon clincher bead where it meets the tire. Sharp? Rough exposed carbon fibers present? Etc.
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CAAD8FRED
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by CAAD8FRED

Do you know any specific rims that are sharp besides Enve and HED?

TobinHatesYou
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by TobinHatesYou

CAAD8FRED wrote:
Mon Oct 07, 2019 5:30 pm
Do you know any specific rims that are sharp besides Enve and HED?

It has happened on "smooth" rims and also on alloy rims too. If you look on these forums, it just happened to someone with Reynolds rims.

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by Junior Varsity

I would just like to correct some information begin discussed in this thread (and in a lot of conversations I see on the net and that I even have in person).

Gumwall is not a color just as skinwall is not a color; these are the main two types of tire types found on bicycles these days.

All of the tires we're talking about here are skinwall where an independent tread extrusion is placed on top of a calendered casing (120tpi nylon in a lot of cases) and then vulcanized. To create the casing, rubber has been 'pressed' into a nylon fabric sheet which is this folded over the beads. This is the only rubber found on the sidewalls making it very thin 'skin' hence the skinwall name. In most cases, the skinwall is black due to the use of carbon black which strengthens the rubber and also helps to retain air (in the case of a tubeless or tubeless ready tire). Tan skinwall has become somewhat popular over the past few years as it provides a classic look in reference to tubular tires which used a coated cotton casing with a pre-vulcanized tread glued on top. It should be noted that a tan sidewall lacks the carbon back and therefore a TLR version doesn't hold air nearly as well as a black skinwall tire. In addition, it's provides less cut and abrasion resistence.
Skinwall Tire.jpg
A gumwall tire is where there is a thick layer of rubber running from bead all the way to the other bead. They're easier to construct thus seen on much lower level bikes (think mass market or even baby jogging strollers.

It's also not correct that a supple sidewall tire is faster as there are so many factors to consider, saying one outweights the others is simply wrong. Like most if not all things in life, everything is relative to something else. Or with bicycle tires, many things.

An open tubular is not 'marketing' speak as it refers to a non-vulcanized casing with a tread glued (epoxied, etc) on top. The casing could be made from cotton, ploy-cotton, silk, etc. It is just a type of clincher.
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Calnago
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by Calnago

That’s good info @juniorvarsity, and yes, an actual “gumwall” is different than a colored skinwall. However, I think when most people refer to “gumwall” these days in the sense of a high quality road tire, they are really referencing the “look” they are after.

And also, I don’t notice any difference between say, a Veloflex Arrenberg (Black sidewall) versus a Veloflex Roubaix (tan sidewall). Granted they are both tubulars with latex tubes so acting as a tubeless that is meant to keep air from escaping is irrelevant anyway. But I also notice no difference in durability either. As far as I know, they are the same tire, except for the color of their sidewalls. The Specialized Turbo Cotton clinchers have the most lovely tan color of any non black sidewall I’ve seen. I seem to remember someone saying (and I have no idea if it’s true or not), that Specialized actually patented that color. Good for them if they did because it’s very nice, so much prettier then the Edsel Whitewall look of the Vittorias.
And agree that a supple tire doesn’t necessarily make it “faster”... if straight line speed is all that counts in a tire then we’d all be riding stiff walled clincher tubeless at fairly high pressures (on good roads). But it’s not, far from it... I’d much rather be riding a supple tubular all day any day than the best clinchers.
And understand that an “open tubular” is often just a name given to the best clincher that a manufacturer produces. They may be largely constructed the same way, with one very important and significant difference. They are “open”, and they have a bead. And thus, they are clinchers. And have to have a supporting rim to mount on, with two relatively high sidewalls, versus an actual tubular which rests uniformly across a shallow rim bed of much the same radius. So yes, I’ll continue to say that the term “Open Tubulars” is marketing speak for “These are really nice clinchers, so nice in fact that we’ve decided to call them “Open Tubulars”.

But tell me, when you refer to “Carbon Black”, what exactly are you referring to? And who is using “carbon black”. Take Veloflex for example... they have a tire called the Carbon, it is black. It is the same construction (as far as I know), as the Arrenberg (also black, just bigger), and the Roubaix (tan sidewalls, but also bigger).
I’m sure all the manufacturers have their “secret sauce” they like to talk about, but you speak of “Carbon Black” as if it’s some generic compound used by many that somehow makes black sidewall tires more durable than the tan sidewall tires.
Last edited by Calnago on Mon Oct 07, 2019 6:39 pm, edited 3 times in total.
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by XCProMD

Carbon black is the filler that you mix with SBR o NBR (styrene-butadiene or nitrile-butadiene rubber, the rubber used in tyres) to modify some of its properties, like abrasion resistance.


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robertbb
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by robertbb

@Junior Varsity

So, if one were to compare two "open tubular" clinchers from the same manufacturer, one with "gum" coloured sidewalls and one with black coloured sidewalls, the black one would be inherently more resistant to cuts?

A good example would be the Veloflex Master vs Veloflex Corsa. Same tyre, different colour sidewall.

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LouisN
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by LouisN

In a conversation I had with Francois Marie, owner of FMB tires, I was asking about their long awaited "carbon" (black sidewall) tubular models. That was 5-6 yrs ago.
He replied that he was always disappointed with the black fabric he got from the manufacturer', that it wasn't as strong as his usual beige one.
When I look at their actual "carbon" models now, I'm guessing he never obtained satisfaction, and decided to simply dye the beige sidewall with black ink :
http://www.fm-boyaux.com/produit.php?re ... ubrique=23

Louis :)

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by Junior Varsity

robertbb wrote:
Mon Oct 07, 2019 11:48 pm
@Junior Varsity

So, if one were to compare two "open tubular" clinchers from the same manufacturer, one with "gum" coloured sidewalls and one with black coloured sidewalls, the black one would be inherently more resistant to cuts?

A good example would be the Veloflex Master vs Veloflex Corsa. Same tyre, different colour sidewall.
Open tubulars are not a vulcanized nylon tire. My previous comment was with regards to tan sidewalls found on vulcanized tires vs. their black counterparts. For open tubulars (non-vulcanized), the color is simply the color.
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robertbb
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by robertbb

Junior Varsity wrote:
Tue Oct 08, 2019 9:11 pm
robertbb wrote:
Mon Oct 07, 2019 11:48 pm
@Junior Varsity

So, if one were to compare two "open tubular" clinchers from the same manufacturer, one with "gum" coloured sidewalls and one with black coloured sidewalls, the black one would be inherently more resistant to cuts?

A good example would be the Veloflex Master vs Veloflex Corsa. Same tyre, different colour sidewall.
Open tubulars are not a vulcanized nylon tire. My previous comment was with regards to tan sidewalls found on vulcanized tires vs. their black counterparts. For open tubulars (non-vulcanized), the color is simply the color.
Got it, thank you!

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by Junior Varsity

Calnago wrote:
Mon Oct 07, 2019 6:39 pm
That’s good info @juniorvarsity, and yes, an actual “gumwall” is different than a colored skinwall. However, I think when most people refer to “gumwall” these days in the sense of a high quality road tire, they are really referencing the “look” they are after.

And also, I don’t notice any difference between say, a Veloflex Arrenberg (Black sidewall) versus a Veloflex Roubaix (tan sidewall). Granted they are both tubulars with latex tubes so acting as a tubeless that is meant to keep air from escaping is irrelevant anyway. But I also notice no difference in durability either. As far as I know, they are the same tire, except for the color of their sidewalls. The Specialized Turbo Cotton clinchers have the most lovely tan color of any non black sidewall I’ve seen. I seem to remember someone saying (and I have no idea if it’s true or not), that Specialized actually patented that color. Good for them if they did because it’s very nice, so much prettier then the Edsel Whitewall look of the Vittorias.
And agree that a supple tire doesn’t necessarily make it “faster”... if straight line speed is all that counts in a tire then we’d all be riding stiff walled clincher tubeless at fairly high pressures (on good roads). But it’s not, far from it... I’d much rather be riding a supple tubular all day any day than the best clinchers.
And understand that an “open tubular” is often just a name given to the best clincher that a manufacturer produces. They may be largely constructed the same way, with one very important and significant difference. They are “open”, and they have a bead. And thus, they are clinchers. And have to have a supporting rim to mount on, with two relatively high sidewalls, versus an actual tubular which rests uniformly across a shallow rim bed of much the same radius. So yes, I’ll continue to say that the term “Open Tubulars” is marketing speak for “These are really nice clinchers, so nice in fact that we’ve decided to call them “Open Tubulars”.

But tell me, when you refer to “Carbon Black”, what exactly are you referring to? And who is using “carbon black”. Take Veloflex for example... they have a tire called the Carbon, it is black. It is the same construction (as far as I know), as the Arrenberg (also black, just bigger), and the Roubaix (tan sidewalls, but also bigger).
I’m sure all the manufacturers have their “secret sauce” they like to talk about, but you speak of “Carbon Black” as if it’s some generic compound used by many that somehow makes black sidewall tires more durable than the tan sidewall tires.

Hi Calnago-

Your comments, while understood, are a bit off base and incorrect. All of the tires you're talking about are cotton casing based tubulars or open tubulars (Vittoria Corsa, Spesh Turbo Cotton, etc.) and not vulcanized clinchers (GP5000, Schwalbe Pro One, Goodyear Eagle F1, etc.) . In that case, the black color is merely an aesthetic. The use of carbon black as an additive in SBR greatly increases the strength of the rubber. All of those tires have a vulcanized tread but not a casing. To be clear, everyone used carbon black in the tread whether an open tubular, tubular or clincher (vulcanized).

Carbon black is not a compound per se, as it is a component in the compound which is a mixture of many, many different additives including silica and graphene in some cases. So yes, I speak of it as it's used by everyone who makes tires that are black. https://en.wikipedia.org/wiki/Carbon_black In 2016, 14 billion tons of carbon black was produced and used.

Open Tubular isn't a marketing name given to a manufacturer's best tires, it is a specific type of consturction for a clincher tire where the casing is generally cotton, or poly-cotton based and not vulcanized. Vulcanized clinchers tires are generally constructed with a nylon casing fabric from 27tpi up to 170 or 180tpi. The tpi in a vulcunized tire does not directly correlate to that of cotton etc. In a vulcanized clincher tires, lack of carbon black in the SBR of the casing rubber will cause it to be more fragile and not hold air as well. I just want to make sure you understand that in this case, you're incorrect and that I would like to provide you the actual information to help you better understand what is arguably one of, if not the most technically advanced and important components on your bike.
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Calnago
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by Calnago

Ok, I think I’ve got it. Carbon Black is simply one of the components that goes into the mix of rubber that ends up as part of the tire tread compound. Got that. They all do it. As for the sidewall color, it’s an aesthetic. Yes, like the difference between the Veloflex Areenberg (black) vs the Veloflex Roubaix (tan). Same tire, just different colored sidewalls. That’s what I was trying to say. And they have cotton casings. The tread is what contains the carbon black component.

But the marketing aspect of calling a clincher an “Open Tubular” is just something we’re going to have to disagree upon. By your logic, if it’s vulcanized, it’s a “clincher”... but if it’s got a nice cotton casing, then it can be a called an “open tubular” by virtue of the fact it’s casing and tread are very similar, if not the same, as the corresponding tubular made by the same manufacturer. Hence the marketing value in calling it that. But at the end of the day, it will not perform the same way as a tubular mounted on a nice shallow rim bed with no abrupt walls to contend with. If it’s open, and it’s got a bead that needs to be “clinched” between two rim walls (i.e., a clincher rim), it’s a clincher, regardless of its construction. It may be a very nice clincher, but it’s still a clincher. “Open Tubular” is 100% a marketing moniker.
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by Junior Varsity

Hi Calnago-

Open tubular is a type of clincher not based upon the level but by how it's constructed. It has a (generally) non-vulcanized fabric casing that has vulcanized tread affixed to it (they're flat when folded). A vulcanized clincher is where the full tire is cured (vulcanized) at one time which gives it its shape. One method is not inherently better than the other, they're different approaches to build a tire to work with a clincher rim towards an intended usage.

Sorry for the horrible effort of an explainer graphic, just hoping a visual may do a better job than I can simply writing it out.
Capture.PNG
But going full circle to the beginning this thread, it's good to see the understanding of gumwall vs. skinwall is understood with respects to clincher tire types! I'm more than happy to continue the conversation on tires, construction methods and types; I just don't want to see it be reduced down to internet arguing where no one wins and we all get annoyed with each other. I understand where you're coming from as generally open tubulars are more expensive and have historically performed better than their vulcanized competitors, but times are changing and new technologies (tubeless ready) are allowing vulcanized clinchers to out perform in both Crr and puncture resistance.

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by Weenie


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