On 2/22/2024 9:26 PM, Jeff Liebermann wrote:
> On Sun, 11 Feb 2024 10:30:11 GMT, Roger Merriman <roger@sarlet.com>
> wrote:
>
>> Gatorskins even have skaterskins as a name, it doesn’t take much digging to find others who find them slippery!
>>
>> They are quite a different beast to the 4 seasons which are just GP5000 with extra protection layer and apparently softer rubber.
>>
>> That Gatorskins have long life expectancy should indicate that the rubber is hard, while can add stuff to try to mitigate soft rubber doesn’t last and hard rubber doesn’t grip still holds.
>
> I have a durometer (Shore A rubber hardness tester)
> <https://www.ebay.com/itm/355478019585>
> <https://www.ebay.com/sch/i.html?_nkw=shore+a+hardness+tester>
> How it works:
> <https://en.wikipedia.org/wiki/Shore_durometer>
>
> I just measured an old Nashbar Slick ATB Tire NS-SBT.
> 26 x 1.25 and not mounted on a wheel.
> Shore A (sA) hardness = 65 to 68 depending on where I measure.
> It really should be mounted and inflated when doing this test because
> the tire hardness will vary with how much the rubber is stretched by
> air pressure. I can try measuring the tires mounted on my two
> bicycles, but that will need to wait a few days.
>
> "Know Your Rubber: A Quick-Start Guide to Mountain Bike Tire Design"
> <https://www.bicycling.com/bikes-gear/a20024960/know-your-rubber-a-quick-start-guide-to-mountain-bike-tire-design/>
> See section on "Tread Compound":
> "For bicycle tires, 70sA is usually considered a harder, more-durable
> compound and 40sA is a supersoft DH compound."
>
> Hmmm... If that's true, then the Nashbar Slick NS-SBT that I just
> tested should have been at the softer end of the sA scale. It wasn't.
> Maybe testing a mounted tire will produce different numbers.
>
>
>

How old is that tire?
The rubber compound gets harder with age.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971

On Thu, 22 Feb 2024 21:37:10 -0600, AMuzi <am@yellowjersey.org> wrote:

>On 2/22/2024 9:26 PM, Jeff Liebermann wrote:
>> On Sun, 11 Feb 2024 10:30:11 GMT, Roger Merriman <roger@sarlet.com>
>> wrote:
>>
>>> Gatorskins even have skaterskins as a name, it doesn’t take much digging to find others who find them slippery!
>>>
>>> They are quite a different beast to the 4 seasons which are just GP5000 with extra protection layer and apparently softer rubber.
>>>
>>> That Gatorskins have long life expectancy should indicate that the rubber is hard, while can add stuff to try to mitigate soft rubber doesn’t last and hard rubber doesn’t grip still holds.
>>
>> I have a durometer (Shore A rubber hardness tester)
>> <https://www.ebay.com/itm/355478019585>
>> <https://www.ebay.com/sch/i.html?_nkw=shore+a+hardness+tester>
>> How it works:
>> <https://en.wikipedia.org/wiki/Shore_durometer>
>>
>> I just measured an old Nashbar Slick ATB Tire NS-SBT.
>> 26 x 1.25 and not mounted on a wheel.
>> Shore A (sA) hardness = 65 to 68 depending on where I measure.
>> It really should be mounted and inflated when doing this test because
>> the tire hardness will vary with how much the rubber is stretched by
>> air pressure. I can try measuring the tires mounted on my two
>> bicycles, but that will need to wait a few days.
>>
>> "Know Your Rubber: A Quick-Start Guide to Mountain Bike Tire Design"
>> <https://www.bicycling.com/bikes-gear/a20024960/know-your-rubber-a-quick-start-guide-to-mountain-bike-tire-design/>
>> See section on "Tread Compound":
>> "For bicycle tires, 70sA is usually considered a harder, more-durable
>> compound and 40sA is a supersoft DH compound."
>>
>> Hmmm... If that's true, then the Nashbar Slick NS-SBT that I just
>> tested should have been at the softer end of the sA scale. It wasn't.
>> Maybe testing a mounted tire will produce different numbers.

>How old is that tire?
>The rubber compound gets harder with age.

Good point. I don't have any receipts on the slicks, but did find
some 2004 receipts for some tubes crammed into nearby boxes from the
same era. Sounds about right. 20 years old. The tires are in good
shape, have had no UV exposure, feel very flexible, no surface
deterioration and no cracks. They've been hanging in an isolated
closet for most of the 20 years.

If I dig enough in my mess, I think there are two more identical slick
tires mounted on wheels. Give me about a week to clear a path to the
bicycle mess.

I just checked the tires on my mtn bike. They're very similar to the
Nashbar slicks, but have a tread pattern instead of a smooth surface.
The tires are flat, I forgot to eat dinner, the wood burner
extinguished itself, I'm tired, etc. Another day please.

--
Jeff Liebermann jeffl@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann <jeffl@cruzio.com> wrote:
> On Thu, 22 Feb 2024 21:37:10 -0600, AMuzi <am@yellowjersey.org> wrote:
>
>> On 2/22/2024 9:26 PM, Jeff Liebermann wrote:
>>> On Sun, 11 Feb 2024 10:30:11 GMT, Roger Merriman <roger@sarlet.com>
>>> wrote:
>>>
>>>> Gatorskins even have skaterskins as a name, it doesn’t take much
>>>> digging to find others who find them slippery!
>>>>
>>>> They are quite a different beast to the 4 seasons which are just
>>>> GP5000 with extra protection layer and apparently softer rubber.
>>>>
>>>> That Gatorskins have long life expectancy should indicate that the
>>>> rubber is hard, while can add stuff to try to mitigate soft rubber
>>>> doesn’t last and hard rubber doesn’t grip still holds.
>>>
>>> I have a durometer (Shore A rubber hardness tester)
>>> <https://www.ebay.com/itm/355478019585>
>>> <https://www.ebay.com/sch/i.html?_nkw=shore+a+hardness+tester>
>>> How it works:
>>> <https://en.wikipedia.org/wiki/Shore_durometer>
>>>
>>> I just measured an old Nashbar Slick ATB Tire NS-SBT.
>>> 26 x 1.25 and not mounted on a wheel.
>>> Shore A (sA) hardness = 65 to 68 depending on where I measure.
>>> It really should be mounted and inflated when doing this test because
>>> the tire hardness will vary with how much the rubber is stretched by
>>> air pressure. I can try measuring the tires mounted on my two
>>> bicycles, but that will need to wait a few days.
>>>
>>> "Know Your Rubber: A Quick-Start Guide to Mountain Bike Tire Design"
>>> <https://www.bicycling.com/bikes-gear/a20024960/know-your-rubber-a-quick-start-guide-to-mountain-bike-tire-design/>
>>> See section on "Tread Compound":
>>> "For bicycle tires, 70sA is usually considered a harder, more-durable
>>> compound and 40sA is a supersoft DH compound."
>>>
>>> Hmmm... If that's true, then the Nashbar Slick NS-SBT that I just
>>> tested should have been at the softer end of the sA scale. It wasn't.
>>> Maybe testing a mounted tire will produce different numbers.
>
>> How old is that tire?
>> The rubber compound gets harder with age.
>
> Good point. I don't have any receipts on the slicks, but did find
> some 2004 receipts for some tubes crammed into nearby boxes from the
> same era. Sounds about right. 20 years old. The tires are in good
> shape, have had no UV exposure, feel very flexible, no surface
> deterioration and no cracks. They've been hanging in an isolated
> closet for most of the 20 years.
>
> If I dig enough in my mess, I think there are two more identical slick
> tires mounted on wheels. Give me about a week to clear a path to the
> bicycle mess.
>
> I just checked the tires on my mtn bike. They're very similar to the
> Nashbar slicks, but have a tread pattern instead of a smooth surface.
> The tires are flat, I forgot to eat dinner, the wood burner
> extinguished itself, I'm tired, etc. Another day please.
>
>
>

Even so that compound seems about right. Most slicks or similar to seem to
have broadly similar properties or compounds.

To further muddy the waters, bike tire use mixes of (ie more than one)
compounds and I believe claim that simply using a durometer doesn’t work as
well on such tires.

Certainly don’t get tires with listed durometer numbers anymore but
hard/soft etc descriptions in general.

Plus within the MTB world not just the compound but how it’s made, so some
tires such a the Magic Mary that is used from Trail riders to DownHill
racers and everything in between.

https://www.schwalbe.com/en/Magic-Mary-11654181

Even a bike park version ie hard compound but DH casing so it’s not trashed
by folks sessioning well bike park trails, as the DH compound would be
trashed in a few runs!

It’s the tire I run on the front, though trail ie lightest version which
produces impressive grip particularly in the slop, and has stopped the bike
from running wide in very wet conditions!

Roger Merriman

On 2/22/2024 10:37 PM, AMuzi wrote:
>>
> How old is that tire?
> The rubber compound gets harder with age.

As I recall, racers used to let their tires age before using them. I
suppose that's the reason?

But if so, it seems they were probably choosing a slight drop in rolling
resistance along with a slight drop in traction. Interesting choice.

--
- Frank Krygowski

Frank Krygowski <frkrygow@sbcglobal.net> wrote:
> On 2/22/2024 10:37 PM, AMuzi wrote:
>>>
>> How old is that tire?
>> The rubber compound gets harder with age.
>
> As I recall, racers used to let their tires age before using them. I
> suppose that's the reason?
>
> But if so, it seems they were probably choosing a slight drop in rolling
> resistance along with a slight drop in traction. Interesting choice.
>

I think that was for tubs and which is rather before my time, I have heard
of it but for what reason not sure.

May well have been another of those someone said it once so it’s been taken
at face value and not questioned since things, this said I believe that
beyond that they are a tube, that construction was different so possibly?

Certainly with clinchers no good reasons to age tires to the best of my
knowledge.

Roger Merriman

Roger Merriman <roger@sarlet.com> wrote:
> Frank Krygowski <frkrygow@sbcglobal.net> wrote:
>> On 2/22/2024 10:37 PM, AMuzi wrote:
>>>>
>>> How old is that tire?
>>> The rubber compound gets harder with age.
>>
>> As I recall, racers used to let their tires age before using them. I
>> suppose that's the reason?
>>
>> But if so, it seems they were probably choosing a slight drop in rolling
>> resistance along with a slight drop in traction. Interesting choice.
>>
>
> I think that was for tubs and which is rather before my time, I have heard
> of it but for what reason not sure.
>
> May well have been another of those someone said it once so it’s been taken
> at face value and not questioned since things, this said I believe that
> beyond that they are a tube, that construction was different so possibly?
>
> Certainly with clinchers no good reasons to age tires to the best of my
> knowledge.
>
> Roger Merriman
>
>

Found a link from 9 years ago which goes someway to explain at least at
scan though it’s quite late here.

https://www.cxmagazine.com/buying-tubulars-tires-early-aging-process-explained?utm_content=cmp-true

Roger Merriman

On 2/23/2024 4:34 PM, Frank Krygowski wrote:
> On 2/22/2024 10:37 PM, AMuzi wrote:
>>>
>> How old is that tire?
>> The rubber compound gets harder with age.
>
> As I recall, racers used to let their tires age before using them. I
> suppose that's the reason?
>
> But if so, it seems they were probably choosing a slight drop in rolling
> resistance along with a slight drop in traction. Interesting choice.
>

I was told it makes the tires more supple, but Rogers link says it's to
allow the glue to cure. I used to leave a new sew up mounted and
inflated (no glue) on an old rim for a while, just to make the mounting
process easier.
--
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