On 6/12/2022 4:27 PM, Frank Krygowski wrote:
> On 6/12/2022 11:12 AM, AMuzi wrote:
>> On 6/12/2022 9:46 AM, Frank Krygowski wrote:
>>> On 6/11/2022 9:53 PM, pH wrote:
>>>>
>>>> I have a Zaffiro on the front and a Continental on the
>>>> back right now.
>>>> It's hard to find decent 27" tires at times.
>>>>
>>>> The Continental is a *bear* to mount dismount and requires
>>>> tire irons. I
>>>> can do the Zaffiro by hand.
>>>>
>>>> Mavic Mod 4 rims.
>>>
>>> I'm sure we've all come across those differences. It makes
>>> me wonder about the tolerances on rim dimensions such as
>>> bead seat diameters, and the tolerances on tire bead
>>> diameters.
>>>
>>> In an ideal world, every (say) 27 inch tire would mount the
>>> same on every 27 inch rim. Ditto for 700C. After all, we
>>> almost never have this problem screwing 1/4-20 nuts onto
>>> 1/4-20 screws.
>>>
>>> (Drivel: Last night I came across a left hand threaded
>>> 1/4-20 nut. A rare item! Being who I am, I saved it.)
>>>
>>
>> It's almost never a difference in bead seat diameter of
>> tire or rim[1]. It's more commonly design errors of the
>> channel between the seats; depth or width or both[2].
>> Followed closely by incorrect rim liner.
>
> I understand, and of course I know every item has
> tolerances. I'm slightly curious about the industry standard
> tolerance for the dimensions I mentioned.
>
> It seems strange to me that one can buy tires that won't fit
> a nominally compatible rim. Given that the depth of the well
> is important, I wonder if there's an industry standard for
> that. If not, I wonder how a design makes it out the door
> without being tested for that.
>
> It's been decades, but I recall one bike convention long ago
> at which a guy was having tremendous difficulty fitting a
> supposedly compatible tire onto a rim. I was one of three
> people attempting to help him, and we all gave up. I assume
> something was badly out of tolerance.
>
> BTW, regarding rim liner or rim tape: On one tour our
> daughter's brand new bike was flatting repeatedly because of
> bad rim tape. In the small town we passed through, all I
> could find was medical adhesive tape. It worked so well that
> as often as not that's become my go-to choice.
>
>

Yes, medical adhesive tape was factory spec for Trek built
wheels for many years.

There are some classically famous oversights such as US made
Trek brand rims of the early 1990s which had almost no drop
from bead seat to center. Those were a real fight, both tire
removal and installation, although once mounted the seats
were correctly sized and functioned.

There was a KinLin (ROC) rim about 8~10 years ago with the
narrowest channel imaginable- not much wider than a valve
but relatively deep. Often couldn't get both tire beads into
it. Those also flatted from inability to use any standard
rim liner.

For those less familiar here are some classic rim sections:
http://www.yellowjersey.org/photosfromthepast/WEINRIMS.JPG

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

AMuzi <am@yellowjersey.org> wrote:
> On 6/12/2022 9:46 AM, Frank Krygowski wrote:
>> On 6/11/2022 9:53 PM, pH wrote:
>>>
>>> I have a Zaffiro on the front and a Continental on the
>>> back right now.
>>> It's hard to find decent 27" tires at times.
>>>
>>> The Continental is a *bear* to mount dismount and requires
>>> tire irons. I
>>> can do the Zaffiro by hand.
>>>
>>> Mavic Mod 4 rims.
>>
>> I'm sure we've all come across those differences. It makes
>> me wonder about the tolerances on rim dimensions such as
>> bead seat diameters, and the tolerances on tire bead diameters.
>>
>> In an ideal world, every (say) 27 inch tire would mount the
>> same on every 27 inch rim. Ditto for 700C. After all, we
>> almost never have this problem screwing 1/4-20 nuts onto
>> 1/4-20 screws.
>>
>> (Drivel: Last night I came across a left hand threaded
>> 1/4-20 nut. A rare item! Being who I am, I saved it.)
>>
>
> It's almost never a difference in bead seat diameter of tire
> or rim[1]. It's more commonly design errors of the channel
> between the seats; depth or width or both[2]. Followed
> closely by incorrect rim liner.
>
> [1] every manufactured thing has some measurable incidence
> of defect but for tires and rims it's vanishingly small.
>
> [2] tires with thicker bead edges will show up as mounting
> difficulty on rims with marginal clearances.

I believe that’s one of the nuts they have been solving with tubeless
tires/rims ie so in theory should work 100% of time and can be inflated
with a track pump ie doesn’t need a compressor etc.

Roger Merriman.

On 6/12/2022 5:52 PM, AMuzi wrote:
> On 6/12/2022 4:27 PM, Frank Krygowski wrote:
>> On 6/12/2022 11:12 AM, AMuzi wrote:
>>> On 6/12/2022 9:46 AM, Frank Krygowski wrote:
>>>> On 6/11/2022 9:53 PM, pH wrote:
>>>>>
>>>>> I have a Zaffiro on the front and a Continental on the
>>>>> back right now.
>>>>> It's hard to find decent 27" tires at times.
>>>>>
>>>>> The Continental is a *bear* to mount dismount and requires
>>>>> tire irons.  I
>>>>> can do the Zaffiro by hand.
>>>>>
>>>>> Mavic Mod 4 rims.
>>>>
>>>> I'm sure we've all come across those differences. It makes
>>>> me wonder about the tolerances on rim dimensions such as
>>>> bead seat diameters, and the tolerances on tire bead
>>>> diameters.
>>>>
>>>> In an ideal world, every (say) 27 inch tire would mount the
>>>> same on every 27 inch rim. Ditto for 700C. After all, we
>>>> almost never have this problem screwing 1/4-20 nuts onto
>>>> 1/4-20 screws.
>>>>
>>>> (Drivel: Last night I came across a left hand threaded
>>>> 1/4-20 nut. A rare item! Being who I am, I saved it.)
>>>>
>>>
>>> It's almost never a difference in bead seat diameter of
>>> tire or rim[1]. It's more commonly design errors of the
>>> channel between the seats; depth or width or both[2].
>>> Followed closely by incorrect rim liner.
>>
>> I understand, and of course I know every item has
>> tolerances. I'm slightly curious about the industry standard
>> tolerance for the dimensions I mentioned.
>>
>> It seems strange to me that one can buy tires that won't fit
>> a nominally compatible rim. Given that the depth of the well
>> is important, I wonder if there's an industry standard for
>> that. If not, I wonder how a design makes it out the door
>> without being tested for that.
>>
>> It's been decades, but I recall one bike convention long ago
>> at which a guy was having tremendous difficulty fitting a
>> supposedly compatible tire onto a rim. I was one of three
>> people attempting to help him, and we all gave up. I assume
>> something was badly out of tolerance.
>>
>> BTW, regarding rim liner or rim tape: On one tour our
>> daughter's brand new bike was flatting repeatedly because of
>> bad rim tape. In the small town we passed through, all I
>> could find was medical adhesive tape. It worked so well that
>> as often as not that's become my go-to choice.
>>
>>
>
> Yes, medical adhesive tape was factory spec for Trek built wheels for
> many years.

Good to know. That means I have a defense against skeptics' comments.

> For those less familiar here are some classic rim sections:
> http://www.yellowjersey.org/photosfromthepast/WEINRIMS.JPG

I have that same graphic in my workshop's filing cabinet.

--
- Frank Krygowski

On Sun, 12 Jun 2022 17:27:54 -0400, Frank Krygowski
<frkrygow@sbcglobal.net> wrote:
>It's been decades, but I recall one bike convention long ago at which a
>guy was having tremendous difficulty fitting a supposedly compatible
>tire onto a rim. I was one of three people attempting to help him, and
>we all gave up. I assume something was badly out of tolerance.
>
>BTW, regarding rim liner or rim tape: On one tour our daughter's brand
>new bike was flatting repeatedly because of bad rim tape. In the small
>town we passed through, all I could find was medical adhesive tape. It
>worked so well that as often as not that's become my go-to choice.

"Warming Tires Makes for Easy Mounting"
<https://www.roadbikerider.com/warming-tires-makes-for-easy-mounting-d3/>

I've only tried mounting oven heating bicycle tires three times and
small portable generator tires a few times. Heating worked nicely
with steel wire bead clincher bicycle tires, but failed with Kevlar
wire bead clinchers. That's because the coefficient of linear thermal
expansion (CTE) for Kevlar is somewhere near zero and negative
(shrinks when heated) while steel expands when heated:

"Kevlar Technical Guide" See CTE numbers in table II-2 on Pg 7:
<https://www.r-g.de/w/images/b/bd/Kevlar_Technical_Guide.pdf>
Kevlar = -2.5*10^-6
Steel = +3.7*10^-6

Hints:
- Wear leather welding gloves while handling warm tires.
- A hair dryer or hot air gun didn't work.
- If you're not sure if you have steel or Kevlar tire, use a magnet to
test for steel. A strong magnet salvaged from a hard disk drive works
nicely even going through the aluminum rim.

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

On Sun, 12 Jun 2022 23:29:46 -0000 (UTC), Roger Merriman
<roger@sarlet.com> wrote:

>AMuzi <am@yellowjersey.org> wrote:
>> On 6/12/2022 9:46 AM, Frank Krygowski wrote:
>>> On 6/11/2022 9:53 PM, pH wrote:
>>>>
>>>> I have a Zaffiro on the front and a Continental on the
>>>> back right now.
>>>> It's hard to find decent 27" tires at times.
>>>>
>>>> The Continental is a *bear* to mount dismount and requires
>>>> tire irons. I
>>>> can do the Zaffiro by hand.
>>>>
>>>> Mavic Mod 4 rims.
>>>
>>> I'm sure we've all come across those differences. It makes
>>> me wonder about the tolerances on rim dimensions such as
>>> bead seat diameters, and the tolerances on tire bead diameters.
>>>
>>> In an ideal world, every (say) 27 inch tire would mount the
>>> same on every 27 inch rim. Ditto for 700C. After all, we
>>> almost never have this problem screwing 1/4-20 nuts onto
>>> 1/4-20 screws.
>>>
>>> (Drivel: Last night I came across a left hand threaded
>>> 1/4-20 nut. A rare item! Being who I am, I saved it.)
>>>
>>
>> It's almost never a difference in bead seat diameter of tire
>> or rim[1]. It's more commonly design errors of the channel
>> between the seats; depth or width or both[2]. Followed
>> closely by incorrect rim liner.
>>
>> [1] every manufactured thing has some measurable incidence
>> of defect but for tires and rims it's vanishingly small.
>>
>> [2] tires with thicker bead edges will show up as mounting
>> difficulty on rims with marginal clearances.
>
>I believe that’s one of the nuts they have been solving with tubeless
>tires/rims ie so in theory should work 100% of time and can be inflated
>with a track pump ie doesn’t need a compressor etc.
>
>Roger Merriman.

Well... I assumed that they had "solved the problem" way back in
"sew-up" days (:-) At least I never had any problems mounting them
(:-)

--
Cheers,

John B.

John B. <slocombjb@gmail.com> wrote:
> On Sun, 12 Jun 2022 23:29:46 -0000 (UTC), Roger Merriman
> <roger@sarlet.com> wrote:
>
>> AMuzi <am@yellowjersey.org> wrote:
>>> On 6/12/2022 9:46 AM, Frank Krygowski wrote:
>>>> On 6/11/2022 9:53 PM, pH wrote:
>>>>>
>>>>> I have a Zaffiro on the front and a Continental on the
>>>>> back right now.
>>>>> It's hard to find decent 27" tires at times.
>>>>>
>>>>> The Continental is a *bear* to mount dismount and requires
>>>>> tire irons. I
>>>>> can do the Zaffiro by hand.
>>>>>
>>>>> Mavic Mod 4 rims.
>>>>
>>>> I'm sure we've all come across those differences. It makes
>>>> me wonder about the tolerances on rim dimensions such as
>>>> bead seat diameters, and the tolerances on tire bead diameters.
>>>>
>>>> In an ideal world, every (say) 27 inch tire would mount the
>>>> same on every 27 inch rim. Ditto for 700C. After all, we
>>>> almost never have this problem screwing 1/4-20 nuts onto
>>>> 1/4-20 screws.
>>>>
>>>> (Drivel: Last night I came across a left hand threaded
>>>> 1/4-20 nut. A rare item! Being who I am, I saved it.)
>>>>
>>>
>>> It's almost never a difference in bead seat diameter of tire
>>> or rim[1]. It's more commonly design errors of the channel
>>> between the seats; depth or width or both[2]. Followed
>>> closely by incorrect rim liner.
>>>
>>> [1] every manufactured thing has some measurable incidence
>>> of defect but for tires and rims it's vanishingly small.
>>>
>>> [2] tires with thicker bead edges will show up as mounting
>>> difficulty on rims with marginal clearances.
>>
>> I believe that’s one of the nuts they have been solving with tubeless
>> tires/rims ie so in theory should work 100% of time and can be inflated
>> with a track pump ie doesn’t need a compressor etc.
>>
>> Roger Merriman.
>
> Well... I assumed that they had "solved the problem" way back in
> "sew-up" days (:-) At least I never had any problems mounting them
> (:-)
>
>
It’s more with tubless that tires can blow off if stuff isn’t correct. Ie
tubes and I assume tubular the pressures will keep the tire on the rim,
while the the reverse is true for tubeless.

Though to be fair most tubeless grumbles I hear In real life is punctures
that don’t seal or simply tires that slowly leak ie faff so that folks
eventually give up at least for a while, rather than tires blowing off.

I believe it’s why hookless rims are coming in.

Roger Merriman

On 6/12/2022 2:52 PM, AMuzi wrote:

<snip>

> Yes, medical adhesive tape was factory spec for Trek built wheels for
> many years.

Argh, it works in an emergency, and is cheap, but messy to remove. I
guess that they figured no one would ever keep a bicycle or a wheel long
enough where it needed to be replaced.

I recall, in the early days of Bike Friday, there was a bad crash during
a mountain descent due to the use by Green Gear of Fiberglas tape, like
packing tape, as rim tape. It heated up due to rim heating, melted, and
caused a blowout and crash <https://www.bikeforums.net/8012759-post19.html>.

I have one roll of Schwalbe 15mm rim tape and one roll of 19mm rim take.
Should be enough. Often sold out of course, like half the Schwalbe
products for the past couple of years.
<https://schwalbetires.com/CLOTH-RIM-TAPE-50M-880001>.

On 6/13/2022 10:50 AM, sms wrote:
> On 6/12/2022 2:52 PM, AMuzi wrote:
>
> <snip>
>
>> Yes, medical adhesive tape was factory spec for Trek built wheels for
>> many years.
>
> Argh, it works in an emergency, and is cheap, but messy to remove. I
> guess that they figured no one would ever keep a bicycle or a wheel long
> enough where it needed to be replaced.

Bullshit. My daughter's bike still has that same tape. That wheel
crossed the Rockies and is still in use. The tape has been through many
tire changes.

--
- Frank Krygowski

On Friday, June 10, 2022 at 4:18:34 PM UTC-4, deaco...@gmail.com wrote:
> For the past few years been running Conti GP 4000's and then the 5000's. I like them they roll well and I get tremendous mileage on them. I can usually get 6000 miles. I swap the front to the rear after about 2200 and then ride them out. I just put an new set on the front no completely worn for sure but I can save it for spare.
>
> My question is if there are better options for the price point. i can get Conti's for around $55. I don't like slow tires and so far rarely flat. However would like to know some other options for riding? Given I prefer speedier tires but don't want to be swapping them out ever 2k.
> Deacon Mark

I've been running Fortezza Tricomps on my commuter (Ksyrium rims) for about 3 years, so I probably have ~5K miles on them, Good wear, good traction, both wet and dry. Before that I had Mavic Yksium (yes, power/grip link combo) which I felt performed better dry, but not so much wet and also wore faster. I have GP5000's on another set of wheels I don't generally commute on, with experience similar to yours.

On 2022-06-12, sms <scharf.steven@geemail.com> wrote:
> On 6/11/2022 6:53 PM, pH wrote:
>
><snip>
>
>> I have a Zaffiro on the front and a Continental on the back right now.
>> It's hard to find decent 27" tires at times.
>
> True. For touring tires there are still a sufficient number of 27" tires
> but for racing tires the choices are few.

Yes, for which I am grateful.
Michelein (sp?) and Hutchison used to make some nice 27" tires...but you're
right, there are still plenty enough to choose from for my modest needs.

pH

On 6/15/2022 12:39 PM, pH wrote:
> On 2022-06-12, sms <scharf.steven@geemail.com> wrote:
>> On 6/11/2022 6:53 PM, pH wrote:
>>
>> <snip>
>>
>>> I have a Zaffiro on the front and a Continental on the back right now.
>>> It's hard to find decent 27" tires at times.
>>
>> True. For touring tires there are still a sufficient number of 27" tires
>> but for racing tires the choices are few.
>
> Yes, for which I am grateful.
> Michelein (sp?) and Hutchison used to make some nice 27" tires...but you're
> right, there are still plenty enough to choose from for my modest needs.
>
> pH
>

Panaracer offers several models in 27"/ 630mm.

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971

On 2022-06-15, AMuzi <am@yellowjersey.org> wrote:
> On 6/15/2022 12:39 PM, pH wrote:
>> On 2022-06-12, sms <scharf.steven@geemail.com> wrote:
>>> On 6/11/2022 6:53 PM, pH wrote:
>>>
>>> <snip>
>>>
>>>> I have a Zaffiro on the front and a Continental on the back right now.
>>>> It's hard to find decent 27" tires at times.
>>>
>>> True. For touring tires there are still a sufficient number of 27" tires
>>> but for racing tires the choices are few.
>>
>> Yes, for which I am grateful.
>> Michelein (sp?) and Hutchison used to make some nice 27" tires...but you're
>> right, there are still plenty enough to choose from for my modest needs.
>>
>> pH
>>
>
> Panaracer offers several models in 27"/ 630mm.
>
I did not like the Panaracer I tried...sidewall too thin and flexy, if I
recall, for my tonnage.

I used to like the old smooth Avocets...guess I'm dating myself!

pH in Aptos

On Wednesday, June 15, 2022 at 9:44:17 p.m. UTC-4, pH wrote:
Snipped
> I used to like the old smooth Avocets...guess I'm dating myself!
>
> pH in Aptos

Those Avocet slicks were fantastic tires even when riding on wet painted stripes on the road. Pete Penseyres rode over a quarter of a mile on a white painted fogline and couldn't get the tire to break loose. Iirc, he did that whilst riding uphill too. I liked the similar Michelin Pro slicks as they too had fantastic grip in the wet.

Cheers