Classic Road - Measuring Rim Size
#1
Senior Member
Thread Starter
Join Date: Mar 2010
Location: Minnesota and Southern California
Posts: 628
Bikes: Specialized Tarmac (carbon), Specialized Roubaix (carbon, wifey), Raleigh Super Course (my favorite), and 2 Centurion project bikes.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Classic Road - Measuring Rim Size
'88 Schwinn World Sport. 6-speed rear freewheel/sprocket assembly with QR skewer. Front skewer also.
Original wheels aren't great; rusty, noticeable lip at seam. I want to replace with similar size, but new. Tires are marked "27 x 1 1/4." Actual outside rim diameter is app. 25 1/4". Do I want a 26" or 27" rim? Can I buy a complete front and rear wheel/spoke assembly? Thanks.
Original wheels aren't great; rusty, noticeable lip at seam. I want to replace with similar size, but new. Tires are marked "27 x 1 1/4." Actual outside rim diameter is app. 25 1/4". Do I want a 26" or 27" rim? Can I buy a complete front and rear wheel/spoke assembly? Thanks.
#3
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,741
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5796 Post(s)
Liked 2,610 Times
in
1,448 Posts
rims are sized by he tires. 27" tires take a 27" rim.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#4
incazzare.
If you want the same size wheels, you can find 27" wheels easily. Note that the diameter of the wheel has nothing to do with the marked size--it's dumb, I know.
Or, if you want a larger selection of tires, you might be able to use 700c wheels, which are slightly smaller in diameter. If you have enough room to adjust the brake pads down 4mm+, you can most likely use 700c.
Here is more info: https://velo-orange.blogspot.com/2011...ake-reach.html
Or, if you want a larger selection of tires, you might be able to use 700c wheels, which are slightly smaller in diameter. If you have enough room to adjust the brake pads down 4mm+, you can most likely use 700c.
Here is more info: https://velo-orange.blogspot.com/2011...ake-reach.html
__________________
1964 JRJ (Bob Jackson), 1973 Wes Mason, 1974 Raleigh Gran Sport, 1986 Schwinn High Sierra, 2000ish Colian (Colin Laing), 2011 Dick Chafe, 2013 Velo Orange Pass Hunter
1964 JRJ (Bob Jackson), 1973 Wes Mason, 1974 Raleigh Gran Sport, 1986 Schwinn High Sierra, 2000ish Colian (Colin Laing), 2011 Dick Chafe, 2013 Velo Orange Pass Hunter
#5
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,741
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5796 Post(s)
Liked 2,610 Times
in
1,448 Posts
2x4s aren't 2 x 4, a 1/4" power drill isn't 1/4", a 10# sack doesn't weigh 10#s, and size 10 shoes aren't 10 of anything.
So the bike world isn't any stranger than the rest of the world in how it approaches nominal sizing.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#6
Insane Bicycle Mechanic
Join Date: Mar 2008
Location: other Vancouver
Posts: 9,843
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 809 Post(s)
Liked 712 Times
in
380 Posts
'88 Schwinn World Sport. 6-speed rear freewheel/sprocket assembly with QR skewer. Front skewer also.
Original wheels aren't great; rusty, noticeable lip at seam. I want to replace with similar size, but new. Tires are marked "27 x 1 1/4." Actual outside rim diameter is app. 25 1/4". Do I want a 26" or 27" rim? Can I buy a complete front and rear wheel/spoke assembly? Thanks.
Original wheels aren't great; rusty, noticeable lip at seam. I want to replace with similar size, but new. Tires are marked "27 x 1 1/4." Actual outside rim diameter is app. 25 1/4". Do I want a 26" or 27" rim? Can I buy a complete front and rear wheel/spoke assembly? Thanks.
__________________
Jeff Wills
Comcast nuked my web page. It will return soon..
Jeff Wills
Comcast nuked my web page. It will return soon..
#7
incazzare.
I don't know that it's unusually dumb. 27" or 700c or any other nominal sizes are just that -- Nominal sizes -- or what we call them. Nominal sizes are often (usually?) different than actual sizes, just approximations for reference.
2x4s aren't 2 x 4, a 1/4" power drill isn't 1/4", a 10# sack doesn't weigh 10#s, and size 10 shoes aren't 10 of anything.
So the bike world isn't any stranger than the rest of the world in how it approaches nominal sizing.
2x4s aren't 2 x 4, a 1/4" power drill isn't 1/4", a 10# sack doesn't weigh 10#s, and size 10 shoes aren't 10 of anything.
So the bike world isn't any stranger than the rest of the world in how it approaches nominal sizing.
It all makes sense if you use the mm sizes--but nobody does.
__________________
1964 JRJ (Bob Jackson), 1973 Wes Mason, 1974 Raleigh Gran Sport, 1986 Schwinn High Sierra, 2000ish Colian (Colin Laing), 2011 Dick Chafe, 2013 Velo Orange Pass Hunter
1964 JRJ (Bob Jackson), 1973 Wes Mason, 1974 Raleigh Gran Sport, 1986 Schwinn High Sierra, 2000ish Colian (Colin Laing), 2011 Dick Chafe, 2013 Velo Orange Pass Hunter
#8
Banned
want to be international about it?
the bead seat diameter is what the many companies use.. its an agreement ..
so tires and rims fit each other
the Number for 27" tires its 630mm
700c just a bit smaller , but incompatible then the number is 622mm
you should see these numbers engraved in the mold, so a raised number on the tire sidewall
2nd number is the width such as 622 - 32
the bead seat diameter is what the many companies use.. its an agreement ..
so tires and rims fit each other
the Number for 27" tires its 630mm
700c just a bit smaller , but incompatible then the number is 622mm
you should see these numbers engraved in the mold, so a raised number on the tire sidewall
2nd number is the width such as 622 - 32
#9
Senior Member
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,741
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Mentioned: 140 Post(s)
Tagged: 1 Thread(s)
Quoted: 5796 Post(s)
Liked 2,610 Times
in
1,448 Posts
As for 29r it's a new creation, and they had to call them that because 26, 27, and 28" were all already taken.
As for the millimeter sizes, they don't make any more sense, if you talk about the nominal tire sizes such as 700c, 650b, etc.
The ERTRO sizes such as 25-622, were intended to clarify the rim/tire fit, but aren't super useful if you're interested in knowing the overall diameter of the tire.
No system of nominal sizing sis ever perfect at describing the actual size, but it's a decent shorthand for reference.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#10
Seńor Member
Join Date: Feb 2013
Posts: 5,066
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 649 Post(s)
Liked 293 Times
in
216 Posts
for the sole purpose
of making this exact suggestion
the only reason i can think of to not use
the far more common 700c wheel size
is if you were trying to restore the bike into a museum peice
and so wanted everything to be original
also
on brakes where the pivot is above the wheel
like road bike style caliper or centre pull brakes
reducing wheel diameter decreases braking power
but on almost every 27" wheel bike i have owned
i converted to 700c for added tire selection
and for extra clearance for fatter tires
Last edited by Wilfred Laurier; 03-07-14 at 09:36 AM.
#11
Senior Member
Join Date: Dec 2009
Location: Houston, TX
Posts: 28,682
Bikes: 1990 Romic Reynolds 531 custom build, Merlin Works CR Ti custom build, super light Workswell 066 custom build
Mentioned: 109 Post(s)
Tagged: 1 Thread(s)
Quoted: 6556 Post(s)
Likes: 0
Liked 58 Times
in
36 Posts
i logged in and came to this thread
for the sole purpose
of making this exact suggestion
the only reason i can think of to not use
the far more common 700c wheel size
is if you were trying to restore the bike into a museum peice
and so wanted everything to be original
also
on brakes where the pivot is above the wheel
like road bike style caliper or centre pull brakes
reducing wheel diameter decreases braking power
but on almost every 27" wheel bike i have owned
i converted to 700c for added tire selection
and for extra clearance for fatter tires
for the sole purpose
of making this exact suggestion
the only reason i can think of to not use
the far more common 700c wheel size
is if you were trying to restore the bike into a museum peice
and so wanted everything to be original
also
on brakes where the pivot is above the wheel
like road bike style caliper or centre pull brakes
reducing wheel diameter decreases braking power
but on almost every 27" wheel bike i have owned
i converted to 700c for added tire selection
and for extra clearance for fatter tires
#12
Senior Member
Thread Starter
Join Date: Mar 2010
Location: Minnesota and Southern California
Posts: 628
Bikes: Specialized Tarmac (carbon), Specialized Roubaix (carbon, wifey), Raleigh Super Course (my favorite), and 2 Centurion project bikes.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Actually found 2 new 27" aluminum rims - a front AND a rear - at the LBS this afternoon. A lucky find, I thought. The front wheel is a bolt-on type, like the one that was already on the Nishiki. That's okay - I get the feeling that this new tire and tube will last for a long time. This will be my first time adjusting cup-and-cone tension with a bolt-on wheel, but it looks easy enough. Thanks all, for the input here.
#13
Insane Bicycle Mechanic
Join Date: Mar 2008
Location: other Vancouver
Posts: 9,843
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 809 Post(s)
Liked 712 Times
in
380 Posts
Actually found 2 new 27" aluminum rims - a front AND a rear - at the LBS this afternoon. A lucky find, I thought. The front wheel is a bolt-on type, like the one that was already on the Nishiki. That's okay - I get the feeling that this new tire and tube will last for a long time. This will be my first time adjusting cup-and-cone tension with a bolt-on wheel, but it looks easy enough. Thanks all, for the input here.
Just a bit of symantics: a "rim" is only the outer hoop of the wheel, without spokes or hub. In general, "rims" are not specific to front or rear. It sounds like you got a nice pair of wheels.
__________________
Jeff Wills
Comcast nuked my web page. It will return soon..
Jeff Wills
Comcast nuked my web page. It will return soon..
#14
Senior Member
Thread Starter
Join Date: Mar 2010
Location: Minnesota and Southern California
Posts: 628
Bikes: Specialized Tarmac (carbon), Specialized Roubaix (carbon, wifey), Raleigh Super Course (my favorite), and 2 Centurion project bikes.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Only after I got the wheel back on the bike did I notice that I'd installed a 700-size tube (with its Presta valve), rather than the Schroeder-valved tube it's meant for. But apart from the larger stem hole (which is covered by the stem nut), it installed perfectly and is still holding air this morning. I guess I'll run it. :-)
#15
Seńor Member
Join Date: Feb 2013
Posts: 5,066
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 649 Post(s)
Liked 293 Times
in
216 Posts
Noted - thanks!
Only after I got the wheel back on the bike did I notice that I'd installed a 700-size tube (with its Presta valve), rather than the Schroeder-valved tube it's meant for. But apart from the larger stem hole (which is covered by the stem nut), it installed perfectly and is still holding air this morning. I guess I'll run it. :-)
Only after I got the wheel back on the bike did I notice that I'd installed a 700-size tube (with its Presta valve), rather than the Schroeder-valved tube it's meant for. But apart from the larger stem hole (which is covered by the stem nut), it installed perfectly and is still holding air this morning. I guess I'll run it. :-)
the only issue
that might happen to the valve
is too much movement
if youre not careful when you are pumping you might tear surrounding tube
#16
Insane Bicycle Mechanic
Join Date: Mar 2008
Location: other Vancouver
Posts: 9,843
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 809 Post(s)
Liked 712 Times
in
380 Posts
Noted - thanks!
Only after I got the wheel back on the bike did I notice that I'd installed a 700-size tube (with its Presta valve), rather than the Schroeder-valved tube it's meant for. But apart from the larger stem hole (which is covered by the stem nut), it installed perfectly and is still holding air this morning. I guess I'll run it. :-)
Only after I got the wheel back on the bike did I notice that I'd installed a 700-size tube (with its Presta valve), rather than the Schroeder-valved tube it's meant for. But apart from the larger stem hole (which is covered by the stem nut), it installed perfectly and is still holding air this morning. I guess I'll run it. :-)
You can get adapters to properly fit a Presta valve in a Schraeder valve hole: https://www.biketiresdirect.com/produ...ta-stem-savers . These will keep the lip of the valve hole from cutting the tube.
__________________
Jeff Wills
Comcast nuked my web page. It will return soon..
Jeff Wills
Comcast nuked my web page. It will return soon..
#17
Senior Member
Thread Starter
Join Date: Mar 2010
Location: Minnesota and Southern California
Posts: 628
Bikes: Specialized Tarmac (carbon), Specialized Roubaix (carbon, wifey), Raleigh Super Course (my favorite), and 2 Centurion project bikes.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Tubes stretch- they're only there to hold the air in. It's the tire that needs to be precisely sized. You might think that "27-inch" and "700C" tires are interchangeable, but they aren't. Trying to put a 27" tire on a 700C wheel will usually result in a blowout.
You can get adapters to properly fit a Presta valve in a Schraeder valve hole: https://www.biketiresdirect.com/produ...ta-stem-savers . These will keep the lip of the valve hole from cutting the tube.
You can get adapters to properly fit a Presta valve in a Schraeder valve hole: https://www.biketiresdirect.com/produ...ta-stem-savers . These will keep the lip of the valve hole from cutting the tube.
This Nishiki has been a hoot. Because of its long, 56 cm top tube, I've been able to make this 50 cm frame fit me quite well, simply by raising the seat post a bit. (I'm 5' 10".) I may spring for a quill stem with a slightly longer extension . . . but it's quite nice as set up currently. I loaned my 56 cm carbon Tarmac to a friend for this morning's ride. I rode the Nishiki. We finished at the base of the 1200 VF hill to my house. I put the Nishiki in the Jeep and rode the Tarmac up that hill. Because it's 16 lbs. it was probably less effort to get it up that hill than it would have been on the 25 lb. Nishiki. But the Tarmac is definitely less comfortable. . . and I'm beginning to understand why the Nishiki gets so much use, and why these old steel bikes are so enjoyable. Thanks. DB