Go Back  Bike Forums > Bike Forums > General Cycling Discussion
Reload this Page >

How many inches in diameter should I expect on a 700C hybrid bike?

Notices
General Cycling Discussion Have a cycling related question or comment that doesn't fit in one of the other specialty forums? Drop on in and post in here! When possible, please select the forum above that most fits your post!

How many inches in diameter should I expect on a 700C hybrid bike?

Old 09-13-20, 01:25 PM
  #1  
IGH_Only
Member
Thread Starter
 
Join Date: Aug 2020
Posts: 30
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 35 Post(s)
Liked 7 Times in 5 Posts
How many inches in diameter should I expect on a 700C hybrid bike?

Tire sizes are so confusing. My understanding is that with the tire (a general 35 mm tire), it should approximate about 27.5"???
IGH_Only is offline  
Old 09-13-20, 02:25 PM
  #2  
Skulking
Junior Member
 
Join Date: Aug 2020
Posts: 14
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Liked 26 Times in 13 Posts
Originally Posted by IGH_Only View Post
Tire sizes are so confusing. My understanding is that with the tire (a general 35 mm tire), it should approximate about 27.5"???
Your question is confusing. If you want to replace just a tire and not the entire wheel, replace the tire with another of the same size, in your case another 700c. If you want to get more confused about bike tire sizing (And possibly then become less confused), this is a useful link which gives explanations and tables of various tire sizes.
Skulking is offline  
Old 09-13-20, 04:24 PM
  #3  
badger1
Senior Member
 
badger1's Avatar
 
Join Date: Oct 2005
Location: Southwestern Ontario
Posts: 4,349
Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1147 Post(s)
Liked 273 Times in 160 Posts
Originally Posted by IGH_Only View Post
Tire sizes are so confusing. My understanding is that with the tire (a general 35 mm tire), it should approximate about 27.5"???
27.2441 inches, to be precise. Took about 5 seconds to calculate.

Nothing confusing about it at all. A "700c" rim is 622 diameter; add tire width in mm X 2 = 692mm = 27.2441 inches.
badger1 is offline  
Likes For badger1:
Old 09-13-20, 05:14 PM
  #4  
IGH_Only
Member
Thread Starter
 
Join Date: Aug 2020
Posts: 30
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 35 Post(s)
Liked 7 Times in 5 Posts
Originally Posted by badger1 View Post
27.2441 inches, to be precise. Took about 5 seconds to calculate.

Nothing confusing about it at all. A "700c" rim is 622 diameter; add tire width in mm X 2 = 692mm = 27.2441 inches.
Thanks, I understood the 622 but I've never seen the formula before and wasn't sure how to calculate how much tire part would add to it.
IGH_Only is offline  
Old 09-16-20, 02:07 AM
  #5  
ShannonM
Senior Member
 
Join Date: Jul 2020
Location: Humboldt County, CA
Posts: 211
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
Likes: 0
Liked 70 Times in 55 Posts
Originally Posted by IGH_Only View Post
Thanks, I understood the 622 but I've never seen the formula before and wasn't sure how to calculate how much tire part would add to it.
Tire width and tire height aren't the same thing... tires aren't cylinders. The same tire will have different dimensions when mounted on different rims. Different tires of the same nominal size will have different dimensions when mounted on the same rim. Many tires will not match their nominal dimensions when mounted on any rim.

To get the exact diameter by calculation, you'd need to measure the height of that tire, when mounted and inflated on that rim... at which point you could just measure the wheel diameter directly and skip the math.

What I'm not grokking is what you'd actually need the number for. The only reason I can come up with would be to calculate the circumference, to calibrate a magnetic-sensor bike computer, but that's always been in millimeters?

--Shannon
ShannonM is offline  
Old 09-16-20, 06:18 AM
  #6  
burnthesheep
Newbie racer
 
Join Date: Feb 2018
Location: Raleigh, NC
Posts: 1,949

Bikes: Propel, red is faster

Mentioned: 32 Post(s)
Tagged: 0 Thread(s)
Quoted: 896 Post(s)
Liked 614 Times in 410 Posts
Sorry, I'm curious now.............why did this question come to mind? What are you working on that knowing this resolves?
burnthesheep is offline  
Likes For burnthesheep:
Old 09-16-20, 09:52 AM
  #7  
Milton Keynes
Senior Member
 
Milton Keynes's Avatar
 
Join Date: May 2016
Posts: 2,979

Bikes: Trek 1100 road bike, Roadmaster gravel/commuter/beater mountain bike

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1331 Post(s)
Liked 263 Times in 146 Posts
Originally Posted by burnthesheep View Post
Sorry, I'm curious now.............why did this question come to mind? What are you working on that knowing this resolves?
Me too. Like, where/how does the 27.5" come into play? I thought 700c was also known as a 29'er since it's 29 inches
Milton Keynes is offline  
Old 09-16-20, 10:07 AM
  #8  
alcjphil
Senior Member
 
alcjphil's Avatar
 
Join Date: Jun 2002
Location: Montreal, Quebec
Posts: 3,947
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 977 Post(s)
Liked 321 Times in 212 Posts
Originally Posted by Milton Keynes View Post
Me too. Like, where/how does the 27.5" come into play? I thought 700c was also known as a 29'er since it's 29 inches
It is only 29 inches if a very wide tire (2+inches) is used
alcjphil is offline  
Old 09-16-20, 04:40 PM
  #9  
IGH_Only
Member
Thread Starter
 
Join Date: Aug 2020
Posts: 30
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 35 Post(s)
Liked 7 Times in 5 Posts
I was just confused much like Milton Keynes because they call it a 29er but it's really not and so forth.
IGH_Only is offline  
Old 09-16-20, 09:15 PM
  #10  
Ironfish653
Senior Member
 
Join Date: Oct 2015
Location: Virginia Beach
Posts: 1,265

Bikes: 1997 Cannondale, 1976 Bridgestone, 1998 Softride

Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 439 Post(s)
Liked 149 Times in 101 Posts
Originally Posted by Milton Keynes View Post
Me too. Like, where/how does the 27.5" come into play? I thought 700c was also known as a 29'er since it's 29 inches
Originally Posted by IGH_Only View Post
I was just confused much like Milton Keynes because they call it a 29er but it's really not and so forth.
The 'Traditonal' names came from a size designation based on the outside diameter of the wheel/tire. 700A, 700B, and 700C all measured (nominally) 700mm in diameter, with A being the widest tire, and C the narrowest, but they all had different diameter rims, in order for the wheel/tire combination to have a 700mm outside diameter. Same goes for the 26" 'fractional' 3-speed wheels and 26" 'decimal' MTB rims.
Also, countries and individual mfgrs had wheels of different dimensions, but all locally given the same 'size', though none were the same.

Since modern bike manufacturing has really coalesced in the later part of the 20th century, a more common international standard was developed, based on the bead seat diameter (BSD) of the wheel rim (also referred to as ERTO) The 700C size, with it's 622mm BSD became 'the' standard road bike wheel size, so that any tire that fit a 622 rim is referred to a a 700C- ##, regardless of tire width, and overall outside diameter.

'29er' MTB wheels are also 622mm BSD, although usually only the wider offroad oriented tires and rims. (30mm+ rims and 45+mm tires) Narrower road / hybrid stuff is called '700c'

The 29er name was to differentiate it from the older (80s-00s) generation 26" MTBs (559mm BSD)

Confusing things, the "27-five" MTB (584mm BSD) doesn't have anything to do with being twenty-seven and a half inches anywhere, it is just in between the 26er and 29er sizes. It also happens to be the same BSD as the 650B that's starting to make inroads in the gravel / audax segments.


Still don't have a clue as to why the OP question, unless he's trying to Rinko it.
Ironfish653 is offline  
Likes For Ironfish653:
Old 09-16-20, 09:39 PM
  #11  
ShannonM
Senior Member
 
Join Date: Jul 2020
Location: Humboldt County, CA
Posts: 211
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
Likes: 0
Liked 70 Times in 55 Posts
29 inches is the approximate outside diameter of an approximately 2 inch wide knobby tire mounted on a 700c rim. Fuzzy memory says that the specific tire was the 700c x 50 WTB Nanoraptor, and that they really did measure right about 29 inches. I was working in a shop when 29 started to happen, and as I recall, the reason that they called them "29 inch" instead of "700c" was that MTB wheels were 26 inch, and 700c was the road wheel size, and they didn't want to confuse anyone.

So they decided to confuse everyone.

Then, when the industry decided that MTB wheels should be 650b, they said, "well, 650b is 584 mm, which is in between 26" MTB (559 mm) and 700c (622 mm), and we called 700c "29 inch" when we put it on a mountain bike, so let's split the difference and call 650b "27.5 inch" if the wheel is going on a mountain bike, so that we won't confuse anyone."

Which confused everyone, by taking the original stupid thing that they did, and squaring the stupid.

If the industry had just called them 700c mountain bikes from the beginning, then 650b would have been 650b instead of 27.5" and everybody would know which tires fit which rims on which bikes, and we can't have that.

I often think that there is a meeting that happens every year at Interbike, where the product managers from the bike and parts manufacturers sit down and figure out what the things are that are comprehensible and how to change them to be more confusing. Tire / rim / wheel sizes are so diabolically confusing that it's gotta be intentional... nobody could possibly screw things up this badly by accident.

--Shannon

Last edited by ShannonM; 09-16-20 at 09:45 PM.
ShannonM is offline  
Likes For ShannonM:
Old 09-16-20, 11:19 PM
  #12  
SurferRosa
Señor Member
 
SurferRosa's Avatar
 
Join Date: Dec 2018
Location: Pac NW
Posts: 2,972

Bikes: Old school lightweights

Mentioned: 45 Post(s)
Tagged: 0 Thread(s)
Quoted: 1224 Post(s)
Liked 977 Times in 597 Posts
I think the problem is this was posted to General Cycling instead of the Completely Obscure subforum.
SurferRosa is offline  
Old 09-16-20, 11:46 PM
  #13  
Darth Lefty 
Disco Infiltrator
 
Darth Lefty's Avatar
 
Join Date: May 2013
Location: Folsom CA
Posts: 11,071

Bikes: Schwinn Paramount, Salsa Timberjack, Diamondback Expert TG, Burley Samba

Mentioned: 65 Post(s)
Tagged: 0 Thread(s)
Quoted: 2023 Post(s)
Liked 600 Times in 417 Posts
If only they’d do it my way I wouldn’t get to explain about obscure French and British and Schwinn sizes, while failing to mention that American standard wheels are the tire size minus four inches (26-4 inches = 559 mm)
__________________
Genesis 49:16-17
Darth Lefty is offline  
Old 09-16-20, 11:48 PM
  #14  
woodcraft
Senior Member
 
woodcraft's Avatar
 
Join Date: Apr 2012
Location: Nor Cal
Posts: 5,272
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 1480 Post(s)
Likes: 0
Liked 517 Times in 305 Posts
Measure it with a tape measure? I don't have a hybrid, but 32mm cx tires measure about 27 1/2"- maybe 27 1/4".
woodcraft is offline  
Old 09-17-20, 07:12 AM
  #15  
Milton Keynes
Senior Member
 
Milton Keynes's Avatar
 
Join Date: May 2016
Posts: 2,979

Bikes: Trek 1100 road bike, Roadmaster gravel/commuter/beater mountain bike

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1331 Post(s)
Liked 263 Times in 146 Posts
I get that it's kind of like how a 2x4 doesn't actually measure 2 inches by 4 inches.
Milton Keynes is offline  
Old 09-17-20, 07:39 AM
  #16  
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Posts: 22,965

Bikes: Some silver ones, a red one, an orange one and a few titanium ones

Mentioned: 113 Post(s)
Tagged: 1 Thread(s)
Quoted: 3503 Post(s)
Liked 970 Times in 603 Posts
Originally Posted by ShannonM View Post
Tire width and tire height aren't the same thing... tires aren't cylinders. The same tire will have different dimensions when mounted on different rims. Different tires of the same nominal size will have different dimensions when mounted on the same rim. Many tires will not match their nominal dimensions when mounted on any rim.
No, a tire isn’t a cylinder. It’s a torus. But for a bicycle tire, the width and height are similar enough to be the same in every practical sense.

To get the exact diameter by calculation, you'd need to measure the height of that tire, when mounted and inflated on that rim... at which point you could just measure the wheel diameter directly and skip the math.
That depends on how “exact” a calculation is needed. Using badger1’s number of 692mm, the size of the tire is 27.2”. If the tire is 1mm taller the diameter is 27.3”. If it is 1mm shorter, it’s still 27.2”. A 10th of an inch isn’t going to cause any real issues with most calculations.

That’s also not taking into account the height difference from loading the wheel which could be substantial and entirely dependent on the pressure used in the tire.
__________________
Stuart Black
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
cyccommute is offline  
Old 09-17-20, 08:09 AM
  #17  
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Posts: 22,965

Bikes: Some silver ones, a red one, an orange one and a few titanium ones

Mentioned: 113 Post(s)
Tagged: 1 Thread(s)
Quoted: 3503 Post(s)
Liked 970 Times in 603 Posts
Originally Posted by ShannonM View Post
29 inches is the approximate outside diameter of an approximately 2 inch wide knobby tire mounted on a 700c rim. Fuzzy memory says that the specific tire was the 700c x 50 WTB Nanoraptor, and that they really did measure right about 29 inches. I was working in a shop when 29 started to happen, and as I recall, the reason that they called them "29 inch" instead of "700c" was that MTB wheels were 26 inch, and 700c was the road wheel size, and they didn't want to confuse anyone.

So they decided to confuse everyone.

Then, when the industry decided that MTB wheels should be 650b, they said, "well, 650b is 584 mm, which is in between 26" MTB (559 mm) and 700c (622 mm), and we called 700c "29 inch" when we put it on a mountain bike, so let's split the difference and call 650b "27.5 inch" if the wheel is going on a mountain bike, so that we won't confuse anyone."

Which confused everyone, by taking the original stupid thing that they did, and squaring the stupid.

If the industry had just called them 700c mountain bikes from the beginning, then 650b would have been 650b instead of 27.5" and everybody would know which tires fit which rims on which bikes, and we can't have that.

I often think that there is a meeting that happens every year at Interbike, where the product managers from the bike and parts manufacturers sit down and figure out what the things are that are comprehensible and how to change them to be more confusing. Tire / rim / wheel sizes are so diabolically confusing that it's gotta be intentional... nobody could possibly screw things up this badly by accident.

--Shannon
It’s actually more confusing than that. The whole lettering designation of the French system is a left over. Wheels with a 650, 650A, 650B and 650C are 4 different sizes of wheels and tires. The point of the letter system was to have wheels the same “size” (outside diameter) with different wheels. A 650 rim (597mm ISO or “Schwinn” size) was meant to be used with narrow tires so that the outside diameter was 650mm. A 650A (590mm or “English 3 speed” size) used a slight wider tire with the same outside diameter. A 650B (584mm) used a 1 1/2 inch tire and a 650C (571) was meant for 2” balloon tires. All 4 were supposed to have the same outside diameter. The 700 system had a similar sizing system. The 700C is about the only thing that survived and it was meant for wide tires...kind of fitting that it’s used for the “29er”.

I’ve been pushing using the ISO size at my co-op classes because of the confusion, especially when it relates to the 27” (630mm) vs 27.5er (584mm) conundrum. Lots of people come in looking for 27.5” tires and want to grab 27” tires off the shelf.
__________________
Stuart Black
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
cyccommute is offline  
Likes For cyccommute:
Old 09-17-20, 08:19 AM
  #18  
cyccommute 
Mad bike riding scientist
 
cyccommute's Avatar
 
Join Date: Nov 2004
Location: Denver, CO
Posts: 22,965

Bikes: Some silver ones, a red one, an orange one and a few titanium ones

Mentioned: 113 Post(s)
Tagged: 1 Thread(s)
Quoted: 3503 Post(s)
Liked 970 Times in 603 Posts
Originally Posted by Milton Keynes View Post
I get that it's kind of like how a 2x4 doesn't actually measure 2 inches by 4 inches.
More useless information: a 2x4 does...or at least did...measure 2” by 4” in the rough hewn state. All lumber sizes are (well, were) the size of the rough cut from the mill. The rough cut lumber was then planed smooth to the size that you buy from the yard. The sizes have changed more recently...by in my lumber yard days nearly 50 years ago, a “2x4” was 1 3/4 x 3 3/4...as a cost savings device. The trees that are being harvested don’t have as much footage of lumber in them as they used to so they cut down the size to save wood and to get more out of the tree.

Even more useless information: I did a research project with the guy who invented the fast curing glue for finger joints in wood. He was Austrian, survived Stalingrad, survived the Russian prisoner of war camps, and drank vodka like a Russian.
__________________
Stuart Black
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Days of Wineless Roads. Bed and Breakfasting along the KATY
Twisting Down the Alley. Misadventures in tornado alley.
cyccommute is offline  
Old 09-17-20, 03:28 PM
  #19  
BoraxKid
Banned
 
Join Date: Jul 2020
Location: Parts Unknown
Posts: 355
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 325 Post(s)
Likes: 0
Liked 99 Times in 65 Posts
Originally Posted by cyccommute View Post
It’s actually more confusing than that. The whole lettering designation of the French system is a left over. Wheels with a 650, 650A, 650B and 650C are 4 different sizes of wheels and tires. The point of the letter system was to have wheels the same “size” (outside diameter) with different wheels. A 650 rim (597mm ISO or “Schwinn” size) was meant to be used with narrow tires so that the outside diameter was 650mm. A 650A (590mm or “English 3 speed” size) used a slight wider tire with the same outside diameter. A 650B (584mm) used a 1 1/2 inch tire and a 650C (571) was meant for 2” balloon tires. All 4 were supposed to have the same outside diameter. The 700 system had a similar sizing system. The 700C is about the only thing that survived and it was meant for wide tires...kind of fitting that it’s used for the “29er”.

I’ve been pushing using the ISO size at my co-op classes because of the confusion, especially when it relates to the 27” (630mm) vs 27.5er (584mm) conundrum. Lots of people come in looking for 27.5” tires and want to grab 27” tires off the shelf.
Oh no. You just reminded me that I actually had a Speedster with an English 3-speed sized (590 mm) wheel in the back and regular Schwinn size (597 mm) wheel in the front. I forgot that I ended up with that setup after changing my back wheel for a better one at the Co-Op like, 4 years ago. I just sold that bike right before I moved (about 4 months back). I wonder if the new owner has gotten any flats...
BoraxKid is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.