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sgtrobo

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Reply with quote  #1 

I have a new Diverge, and it fits "approximately" 38c with some decent room, and it supposed fits a 42c tire"

"The new frame will comfortably fit up to 700x42mm tires with plenty of room for mud, too."
- from Specialized's website

So when I tried the Sawtooth 42c tires on them, I was quite dismayed to find that they rubbed the non-drive-side chainstay.

I finally got some calipers to measure my tires on various wheelsets and I found some rather surprising results:

38c Specialized Terra Pros + Roval Control carbon SL(i22) = 39.65c (awesome tires, BTW)
42c Specialized Sawtooths + Industry9 245 Trail (i24.5)= 43.60c 
38c Specialized Trigger Pros + Roval SLX24 (i20)= 37.2c 

I've read that some tires (for example, Kenda Flintridge, Panaracer GravelKing SK, among others) measure notably larger than their actual claimed size.  


If there is a running list of actual (measured) gravel tire sizes, I'd like to at least contribute my own findings as well as check other tires. I know there is one for the "plus" sized MTB tires (i.e. the 27.5+, ~3" tires)

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Croz

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Reply with quote  #2 
The issue you'll run into and why there is no actual list is because any given tire will measure differently depending on the rim it is mounted on. You mentioned that you measured some tires on "various wheelsets". A 38mm tire mounted on a rim with an inner width of 21mm will measure out to a different size than that same tire mounted on a rim that is 24mm (inner width) or one that is 18mm, etc.  While yes, some tires will run big for their designated size and some may run small if measured on the same rim - unless all your wheels have the exact same rim, it isn't quite as big a deal. Yes, if I have a tight fit for tire "A" on my bike and I want to try tire "B", but know it tends to run big - I'd be hesitant before I tossed down $100 or more for a pair of tires...

I'd also add that if the tire is rubbing on just the non-drive side - it may be worth checking the dish of that wheel. The wheel should sit centered between the stays and if it doesn't something isn't right.
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sully

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Reply with quote  #3 
28mm Gravel Kings on either i19 or i21 measure 26mm @ 60 psi.
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scotjonscot

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Reply with quote  #4 
Quote:
Originally Posted by Croz
The issue you'll run into and why there is no actual list is because any given tire will measure differently depending on the rim it is mounted on. You mentioned that you measured some tires on "various wheelsets". A 38mm tire mounted on a rim with an inner width of 21mm will measure out to a different size than that same tire mounted on a rim that is 24mm (inner width) or one that is 18mm, etc.  While yes, some tires will run big for their designated size and some may run small if measured on the same rim - unless all your wheels have the exact same rim, it isn't quite as big a deal. Yes, if I have a tight fit for tire "A" on my bike and I want to try tire "B", but know it tends to run big - I'd be hesitant before I tossed down $100 or more for a pair of tires...

I'd also add that if the tire is rubbing on just the non-drive side - it may be worth checking the dish of that wheel. The wheel should sit centered between the stays and if it doesn't something isn't right.


Exactly correct
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chas

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https://docs.google.com/spreadsheets/d/1dyYRfhNdFUIbeF1BiQpMyQnhbepy6nxK9DDgd7BhYSk/edit#gid=0

(please be careful if you feel the need to edit)
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dangle

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Reply with quote  #6 
Quote:
Originally Posted by Croz
The issue you'll run into and why there is no actual list is because any given tire will measure differently depending on the rim it is mounted on. You mentioned that you measured some tires on "various wheelsets". A 38mm tire mounted on a rim with an inner width of 21mm will measure out to a different size than that same tire mounted on a rim that is 24mm (inner width) or one that is 18mm, etc.


Croz hits the nail on the head. There can also be variances based on the rim sidewall. I have an American Classic wheelset with a 22mm ID where tires measure marginally smaller than on a 21mm ID Stan's wheel at the same pressure.

Also, flat tires and dirty water bottle nozzles to anybody that uses "c" as a unit of measurement when they actually mean mm. :-)
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sgtrobo

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Reply with quote  #7 
Quote:
Originally Posted by dangle


Also, flat tires and dirty water bottle nozzles to anybody that uses "c" as a unit of measurement when they actually mean mm. :-)


mm takes, literally, twice as long to type as mm
I'm all about efficiency!   [biggrin]
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sgtrobo

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Reply with quote  #8 
Quote:
Originally Posted by chas
https://docs.google.com/spreadsheets/d/1dyYRfhNdFUIbeF1BiQpMyQnhbepy6nxK9DDgd7BhYSk/edit#gid=0

(please be careful if you feel the need to edit)


 chas, very interesting!

thanks a ton!
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dangle

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Reply with quote  #9 
Quote:
Originally Posted by sgtrobo


mm takes, literally, twice as long to type as mm
I'm all about efficiency!   [biggrin]


Ha, I love it!
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Croz

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Reply with quote  #10 
Quote:
Originally Posted by chas
https://docs.google.com/spreadsheets/d/1dyYRfhNdFUIbeF1BiQpMyQnhbepy6nxK9DDgd7BhYSk/edit#gid=0

(please be careful if you feel the need to edit)


Well, I stand corrected about the list... it's always good to learn about new resources. I particularly like that it has the rims they are measured on and the psi. Nice.

Now if there was a list of what tires will not fit on or set up tubeless on what rims I could've saved myself a few hours last week trying to get a friend set up with some WTB Nanos.
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