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tyre bead tightness

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Julian Bradfield

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Feb 13, 2021, 9:45:22 AM2/13/21
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I was idly pondering: what determines this? I have memories of wheels
and tyres where getting the tyre off was a 5-minute exercise of
holding down three tyre levers and working them round, while putting
them back on was another major effort, sometimes beyond the strength
of my thumbs and requiring serious force with a lever. However, on my
current bike, the tyres are so loose-fitting that not only is putting
them back on trivial, I can even take them off just with my hands.

Is this a change in tyre design, or just a variation between different
tyre designs?

--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

Nick Maclaren

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Feb 13, 2021, 11:17:52 AM2/13/21
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In article <slrns2fpf...@home.stevens-bradfield.com>,
Julian Bradfield <j...@inf.ed.ac.uk> wrote:
>I was idly pondering: what determines this? I have memories of wheels
>and tyres where getting the tyre off was a 5-minute exercise of
>holding down three tyre levers and working them round, while putting
>them back on was another major effort, sometimes beyond the strength
>of my thumbs and requiring serious force with a lever. However, on my
>current bike, the tyres are so loose-fitting that not only is putting
>them back on trivial, I can even take them off just with my hands.
>
>Is this a change in tyre design, or just a variation between different
>tyre designs?

I don't think that it's that systematic. Rims and tyres vary slightly,
not least because the ISO value does not specify the outer rim size,
and some combinations do not match well. And there are also wheel
size and bead type effects, so its not a simple matter of exactly
what the diameters are.


Regards,
Nick Maclaren.

Guy Gadboit

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Feb 13, 2021, 12:06:02 PM2/13/21
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Thick rim tape can make it harder too, especially to get the tyre back
on.

Brand new tyres are also worse. They stretch a bit once they've been on
there for a while.

I had some Rigida rims in the summer that were extremely hard to get the
tyres onto so it certainly does still happen. I didn't just need tyre
levers, but cable ties to stop the tyre popping back out again.

"Tubeless ready" rims add a couple of new sources of frustation. It can
be hard when getting them off to push the bead out of the airtight
groove in the rim. Then they're annoying to get back on because the bead
doesn't go into the groove properly. Overinflating and letting the tyre
down again is often the best approach. But it's pretty annoying doing
this with a minipump.

Tosspot

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Feb 13, 2021, 4:01:32 PM2/13/21
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On 13/02/2021 15:44, Julian Bradfield wrote:
> I was idly pondering: what determines this? I have memories of wheels
> and tyres where getting the tyre off was a 5-minute exercise of
> holding down three tyre levers and working them round, while putting
> them back on was another major effort, sometimes beyond the strength
> of my thumbs and requiring serious force with a lever. However, on my
> current bike, the tyres are so loose-fitting that not only is putting
> them back on trivial, I can even take them off just with my hands.
>
> Is this a change in tyre design, or just a variation between different
> tyre designs?

I'm going to say it again, it's all technique. I mean, if one bead will
go on, the other will. It comes down to keeping the bead in the well of
the rim while buggering about on the other side of the wheel. I
consider zip ties disposable items for this process, Sheldon used old
fashion toe straps.

Wide tyres wrt to rims don't help. Overly shallow wells don't, but if
one side will go on, so will the other. Oh, and slim fit tyre levers, I
like;

https://www.amazon.co.uk/Schwalbe-3-Piece-Set-Tyre-Levers/dp/B07PMSC1K7

Just my tuppence worth.

Zebee Johnstone

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Feb 13, 2021, 4:14:03 PM2/13/21
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In uk.rec.cycling.moderated on Sat, 13 Feb 2021 21:01:59 +0100
Tosspot <yea...@nobut.no> wrote:
> I'm going to say it again, it's all technique. I mean, if one bead will
> go on, the other will. It comes down to keeping the bead in the well of
> the rim while buggering about on the other side of the wheel. I
> consider zip ties disposable items for this process, Sheldon used old
> fashion toe straps.
>

I dunno.... I had alex rims on the Encore till the twonks at a
bikeshop messed up fixing the hub gears and didn't do the spokes
properly. SO they replaced it with a velocity rim of a different
profile.

I could get the marathon plus off the alex with reasonable ease.

I couldn't even get the lever all the way in on the velocity!

It was as though someone had glued the tyre on. Even using my not
inconsiderable weight squishing the tyre on the kerbing didn't shift
it. WAlked home, took wheel to shop. Took their biggest bloke some
time to get the tyre off...

CHanged to a wider Marathon and while I could with a deal of effort
get that on and off it was still much harder to do on the velocity rim
compared to the Alex.

Zebee

Roger Merriman

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Feb 13, 2021, 5:53:56 PM2/13/21
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Some of the early tubeless tires where very tight! Much better now, though
I haven’t yet moved to tubeless as well for me tunes do just work.

Roger Merriman

Rob Morley

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Feb 14, 2021, 7:51:06 AM2/14/21
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On Sat, 13 Feb 2021 09:05:45 -0800 (PST)
Guy Gadboit <benc....@googlemail.com> wrote:

> Overinflating and letting
> the tyre down again is often the best approach. But it's pretty
> annoying doing this with a minipump.

This is why we have a compressor at home, and usually carry a CO2
inflator (and several cartridges) on the bike.

Sam Wilson

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Feb 15, 2021, 8:34:09 AM2/15/21
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Julian Bradfield <j...@inf.ed.ac.uk> wrote:
> I was idly pondering: what determines this? I have memories of wheels
> and tyres where getting the tyre off was a 5-minute exercise of
> holding down three tyre levers and working them round, while putting
> them back on was another major effort, sometimes beyond the strength
> of my thumbs and requiring serious force with a lever. However, on my
> current bike, the tyres are so loose-fitting that not only is putting
> them back on trivial, I can even take them off just with my hands.
>
> Is this a change in tyre design, or just a variation between different
> tyre designs?

Depending on your technique it may also depend on the depth of the well in
the rim.

Sam

--
The entity formerly known as Sam.W...@ed.ac.uk
Spit the dummy to reply

Tosspot

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Feb 15, 2021, 8:34:14 AM2/15/21
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I have very limited experience with tubeless but they do appear to be a
whole different kettle of marmosets, not sure why.

David Damerell

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Feb 19, 2021, 7:54:33 AM2/19/21
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Quoting Julian Bradfield <j...@inf.ed.ac.uk>:
>Is this a change in tyre design, or just a variation between different
>tyre designs?

I've often found Continentals to be very tight; I did return one to the
bike shop because it was actually impossible for me to fit it, and I like
to think I'm not completely inept at it.
--
David Damerell <dame...@chiark.greenend.org.uk>
Clown shoes. I hope that doesn't bother you.
Today is Second Tuesday, February.
Tomorrow will be Second Wednesday, February.

Rob Morley

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Feb 19, 2021, 8:43:57 AM2/19/21
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On Sat, 13 Feb 2021 22:53:44 -0000 (UTC)
Roger Merriman <ro...@sarlet.com> wrote:

> Some of the early tubeless tires where very tight! Much better now,
> though I haven’t yet moved to tubeless as well for me tunes do just
> work.
>

https://www.youtube.com/watch?v=WGS029Peq7k


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