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rim - tire?



 
 
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  #1  
Old June 29th 18, 11:04 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 933
Default rim - tire?

How do I measure a rim in order to find out
what tire (clincher) will fit?

Both practically (how to get the size) and then
how to convert it into suitable tire
designations/dimensions?

--
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  #2  
Old June 29th 18, 03:25 PM posted to rec.bicycles.tech
AMuzi
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Default rim - tire?

On 6/29/2018 5:04 AM, Emanuel Berg wrote:
How do I measure a rim in order to find out
what tire (clincher) will fit?

Both practically (how to get the size) and then
how to convert it into suitable tire
designations/dimensions?


If there are no markings and no tire is fitted, you can
measure the outside diameter minus (depth from lip to tire
seat x2) /2 which give you the effective radius from which
to solve for circumference.
584mm=F9, 650B
590=EA3
597=EA1
622=700C
630=K2, 27
635=F4 and so on.

--
Andrew Muzi
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Open every day since 1 April, 1971


  #3  
Old June 29th 18, 05:24 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 933
Default rim - tire?

AMuzi wrote:

How do I measure a rim in order to find out
what tire (clincher) will fit?

Both practically (how to get the size) and
then how to convert it into suitable tire
designations/dimensions?


If there are no markings and no tire is
fitted,


Right, that's the situation for a stack of
rims...

you can measure the outside diameter minus
(depth from lip to tire seat x2) /2 which give
you the effective radius from which to solve
for circumference.


Great, you have a trick for getting the OD,
because of the rims being bulged at the center
obstructing measure tape, ruler, or a
folding rule? Put it against a wall and make
a mark?

584mm=F9, 650B
590=EA3
597=EA1
622=700C
630=K2, 27
635=F4 and so on.


also starring:

590 = 650A
635 = 700B

But what are F9, EA3, EA1, K2, and F4?

--
underground experts united
http://user.it.uu.se/~embe8573
  #4  
Old June 29th 18, 06:08 PM posted to rec.bicycles.tech
David Scheidt
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Posts: 1,261
Default rim - tire?

Emanuel Berg wrote:
:AMuzi wrote:

: How do I measure a rim in order to find out
: what tire (clincher) will fit?
:
: Both practically (how to get the size) and
: then how to convert it into suitable tire
: designations/dimensions?
:
:
: If there are no markings and no tire is
: fitted,

:Right, that's the situation for a stack of
:rims...

: you can measure the outside diameter minus
: (depth from lip to tire seat x2) /2 which give
: you the effective radius from which to solve
: for circumference.

:Great, you have a trick for getting the OD,
:because of the rims being bulged at the center
bstructing measure tape, ruler, or a
:folding rule? Put it against a wall and make
:a mark?

if you ahve a stack of them, put the ruller on the wall.

: 584mm=F9, 650B
: 590=EA3
: 597=EA1
: 622=700C
: 630=K2, 27
: 635=F4 and so on.

:also starring:

: 590 = 650A
: 635 = 700B

:But what are F9, EA3, EA1, K2, and F4?

rim sizes. google 'em.

--
sig 39
  #5  
Old June 29th 18, 10:43 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 6,167
Default rim - tire?

On 6/29/2018 6:04 AM, Emanuel Berg wrote:
How do I measure a rim in order to find out
what tire (clincher) will fit?

Both practically (how to get the size) and then
how to convert it into suitable tire
designations/dimensions?


Here's an article on how to measure rims, assuming no markings.

https://www.sheldonbrown.com/rim-sizing.html


--
- Frank Krygowski
  #6  
Old June 30th 18, 12:13 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 933
Default rim - tire?

David Scheidt wrote:

But what are F9, EA3, EA1, K2, and F4?


rim sizes. google 'em.


Got any hits in particular you'd like to share?

--
underground experts united
http://user.it.uu.se/~embe8573
  #7  
Old June 30th 18, 12:14 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 933
Default rim - tire?

Frank Krygowski wrote:

Here's an article on how to measure rims, assuming no markings.

https://www.sheldonbrown.com/rim-sizing.html


Great, thanks!

--
underground experts united
http://user.it.uu.se/~embe8573
  #8  
Old June 30th 18, 05:43 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
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Posts: 933
Default rim - tire?

Frank Krygowski wrote:

Here's an article on how to measure rims, assuming no markings.

https://www.sheldonbrown.com/rim-sizing.html


What does this mean:

... then dividing by pi (3.142) the
diameter is 518.5mm. 16mm additional (twice
the depth of the well) gives 534 mm, but
the bead seat diameter is be about 10 mm
smaller, and this is a 520 mm rim.

Why not stop at 518.5mm?

--
underground experts united
http://user.it.uu.se/~embe8573
  #9  
Old June 30th 18, 10:16 PM posted to rec.bicycles.tech
Frank Krygowski[_2_]
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Posts: 7,053
Default rim - tire?

On Saturday, June 30, 2018 at 12:43:30 PM UTC-4, Emanuel Berg wrote:
Frank Krygowski wrote:

Here's an article on how to measure rims, assuming no markings.

https://www.sheldonbrown.com/rim-sizing.html


What does this mean:

... then dividing by pi (3.142) the
diameter is 518.5mm. 16mm additional (twice
the depth of the well) gives 534 mm, but
the bead seat diameter is be about 10 mm
smaller, and this is a 520 mm rim.

Why not stop at 518.5mm?


He used the tape to measure the outside diameter of the inside bottom (AKA inner
well) of the rim. but you want the bead seat diameter instead - the diameter
of the surfaces the tires bead sit on.

The well is deeper (or smaller diameter) than the bead seat. If it were not, you
wouldn't be able to get the tire mounted.

- Frank Krygowski
  #10  
Old July 5th 18, 03:26 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 933
Default rim - tire?

Frank Krygowski wrote:

Why not stop at 518.5mm?


He used the tape to measure the outside
diameter of the inside bottom (AKA inner
well) of the rim. but you want the bead seat
diameter instead - the diameter of the
surfaces the tires bead sit on.

The well is deeper (or smaller diameter) than
the bead seat. If it were not, you wouldn't
be able to get the tire mounted.


Yes, what I mean is, don't you get the correct
result anyway by starting from the inner well
and then move up to the closest tire?

Specifically, the issue is 609, 622, 630, and
635 rims.

635 rims are the old-school V-rims with spokes
at a center line. The rear wheel comes with
pre-Torpedo hubs, like the Swedish Novo and
most likely other brands for other countries.
So you can identify the 635s by that.

630 are often thin, 32, as in 32-630 or
27x1-1/4, the old-school road bike standard
(which is great by the way).

Remain 622 (the most-common 28) and the "wierd
Dutch size" 609 which is a 27. (I think you can
use 609 on 622 bikes with no real disadvantage,
at least if you have 609 both rear and front.
635 tho you cannot have on 622 bikes as they
wont fit but hit the fender and/or stays.)

I found it is easier solve the rim size issue
like this. Whenever a tire is removed from
a rim, take the rim to a wall, put it against
it and make a mark with the size on the just
removed tire. Repeat every time there is
a rim/tire that isn't already on the wall.

--
underground experts united
http://user.it.uu.se/~embe8573
 




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