Rolling resistance of wide tires

shiggy wrote:And offered in 30mm and 36mm, no 34mm. Bikerumor is a poor source, and that is 6.5 years old

Yes, I'm tracking that they've updated their lineup. The example may no longer be correct but the principle still applies that construction may change across a model depending on size.

pushstart wrote:

Yes, I'm tracking that they've updated their lineup. The example may no longer be correct but the principle still applies that construction may change across a model depending on size.

MAY change? Can you give one example where the construction used in the “same” model is unique to the size simply because of the size?

As stated before, WTB offers ALL of the casing constructions in BOTH widths

pushstart wrote:

Yes, I'm tracking that they've updated their lineup. The example may no longer be correct but the principle still applies that construction may change across a model depending on size.

Some do. Most don’t. I guess the most likely exceptions would be when a manufacturer decides to jump a model by an unusual number of sizes, say expanding a 33mm cross tire up into gravel range of sizes.
Some of the WTB stuff described was swapping the tread pattern onto a completely different carcass. In many cases where manufacturers change the build across a model, its usually less radical, more along the lines of adding or removing a layer or so of puncture protection.
Schwalbe, who knows. It would be a lifetime of work just trying to sort out and explain all the compounds and protection belts and sizes etc. "Evo blah blah blah MonsterSkin TLE...” I like many schwalbes but hesitate to buy because its so freaking hard to figure out what you’re getting.
Riddler is a slow tire BTW, even compared with some tires that are more robust. Not sure why someone would use them.

shiggy wrote:
MAY change? Can you give one example where the construction used in the “same” model is unique to the size simply because of the size?

As stated before, WTB offers ALL of the casing constructions in BOTH widths

Sure, here's another example, more relevant for this forum:  Panaracer GravelKing.  Different tread thickness in the 32mm vs. the 35 and 40.  And the 32mm is a lot slower -- shocker.

https://www.bicyclerollingresistance.com/specials/gravelking-comparison

And, heck, another example where construction changes when you might not expect is the Rene Herse Barlow Pass vs. Snoqualmie Pass (yes, technically they have different names, but the only thing that is supposed to be different is the size).  The Snoqualmie Pass has thinner tread -- and is lighter than the EL BP.  I'm not sure that was intentional, but it's a difference in construction that means you can't compare crr for BP and SP.

I'm not claiming this is common practice, but just that it happens and one should make sure you're comparing apples to apples.  

pushstart wrote:

Sure, here's another example, more relevant for this forum:  Panaracer GravelKing.  Different tread thickness in the 32mm vs. the 35 and 40.  And the 32mm is a lot slower -- shocker.

<a href="https://www.bicyclerollingresistance.com/specials/gravelking-comparison" target="_blank">https://www.bicyclerollingresistance.com/specials/gravelking-comparison</a>

And, heck, another example where construction changes when you might not expect is the Rene Herse Barlow Pass vs. Snoqualmie Pass (yes, technically they have different names, but the only thing that is supposed to be different is the size).  The Snoqualmie Pass has thinner tread -- and is lighter than the EL BP.  I'm not sure that was intentional, but it's a difference in construction that means you can't compare crr for BP and SP.

I'm not claiming this is common practice, but just that it happens and one should make sure you're comparing apples to apples.  

Yet the casing construction remains the same

shiggy wrote:
Yet the casing construction remains the same

I'm really not sure what point you're trying to make.  The sidewall material may be the same, but if it's not the same tread then the tire construction is obviously not the same ...  and this is born out by measured rolling resistance numbers (e.g. in case of GravelKing) that demonstrate the risk of comparing tires from the same model lineup when the construction has changed.

pushstart wrote:

I'm really not sure what point you're trying to make.  The sidewall material may be the same, but if it's not the same tread then the tire construction is obviously not the same ...  and this is born out by measured rolling resistance numbers (e.g. in case of GravelKing) that demonstrate the risk of comparing tires from the same model lineup when the construction has changed.

 

First, it is the casing material and construction, not just the “sidewall material”.
Yes, tread rubber thickness can make big differences. That thickness also changes with use.
Add in there are manufacturing variations in the rubber that are difficult to control, largely from the relative humidity of the air in the factory. Rubber absorbs water during production. Higher humidity, the more the rubber weighs and affects how it vulcanizes and the performance. 

And it is not uncommon for the tread thickness to vary around the tire.

You can ignore him, he's just arguing for the sake of arguing at this point.

Ted King and Jan Heine discuss the real world reasons for tire size and pressure choices, including if 32mm tires will ever become the norm in the World Tour.
https://overcast.fm/+NWXK4gBh0

Another example of construction differences with width, from BRR:
-----------------------------
The 40 mm Terra Speed is not just a slightly larger version when compared to the 35 mm Terra Speed, but the construction also has been beefed up. The obvious difference can be found in the thickness of the tread (+ 0.4 mm) and the thickness of the sidewalls (+ 0.1 mm). This extra material results in a stronger and more durable tire, which also shows in the tread puncture test where the 40 mm Terra Speed performs ~ 30% better.

Luckily, this somewhat heavier construction hardly affects the performance in the rolling resistance tests. The low rolling resistance indicates the compound is the same (fast) version of the Black Chili compound and not a slower, grippier version that they use on some of their other off-road tires. All in all, the 40 mm version of the Terra Speed looks like an even better tire than the 35 mm version if you don't mind the increased weight.

Jump over to our comparison section to fully compare the 35 mm and 40 mm versions of the Terra Speed: Terra Speed 35 vs Terra Speed 40

https://www.bicyclerollingresistance.com/cx-gravel-reviews/continental-terra-speed-40