25 and 28mm tires measuring the same on the rim?
03-01-21, 10:53 AM
#26
Newbie racer
Join Date: Feb 2018
Posts: 3,406
Bikes: Propel, red is faster
Mentioned: 34 Post(s)
Tagged: 0 Thread(s)
Quoted: 1575 Post(s)
Liked 1,569 Times
in
974 Posts
How new or old are each of the tires? An old 25mm stretched out some might measure closer at first to a brand spankin new 28mm of the same tire.
Give that 28mm a month or two, it'll grow.
Give that 28mm a month or two, it'll grow.
03-01-21, 06:43 PM
#27
Faster!
Thread Starter
Join Date: Sep 2008
Location: NYC
Posts: 23
Bikes: Breezer Thunder, Breezer Venturi, Merlin Works CR 6/4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
More good stuff.
mstateglfr Like yourself, I was also thinking that putting a larger size of the same make/model of tire on the same rim would, indeed, give me a few extra mm but I'm learning that is not always the case.
To Wildwood 's point of N+1 I do also have a gravel bike that has some 32mm Continental 4 season slicks on some Zipp Course 30 rims and they measure 32.4mm. The combination of wheels, tire width and stiffness make a pronounced difference in feel; the gravel bike feels slow as hell getting up to speed but OTOH that extra air volume really works. Over some thousands of miles, I've broken a spoke but not had a pinch flat, or anything that felt like it almost was.
I'll report back in a month or two with news of whether or not the "28mm" 5000s has stretched at all.
mstateglfr Like yourself, I was also thinking that putting a larger size of the same make/model of tire on the same rim would, indeed, give me a few extra mm but I'm learning that is not always the case.
To Wildwood 's point of N+1 I do also have a gravel bike that has some 32mm Continental 4 season slicks on some Zipp Course 30 rims and they measure 32.4mm. The combination of wheels, tire width and stiffness make a pronounced difference in feel; the gravel bike feels slow as hell getting up to speed but OTOH that extra air volume really works. Over some thousands of miles, I've broken a spoke but not had a pinch flat, or anything that felt like it almost was.
I'll report back in a month or two with news of whether or not the "28mm" 5000s has stretched at all.
03-02-21, 07:40 AM
#28
Senior Member
I think there must be a lot of variance between the sizes of different manufacturers. The ostensibly 700x28c Specialized Armadillos I have on my bike now are considerably narrower than the Vittoria Randonneurs and Kenda Kwiks that I used to run (it's extremely obvious considering that I used to use 28/32 tubes but now I use 23/25 tubes without any issues.
03-04-21, 11:20 AM
#29
Senior Member
Join Date: Aug 2017
Location: Wisconsin
Posts: 521
Bikes: 2015 Felt Z75 Disc, 2008 Fuji Cross Comp, 2010 Trek Navigator 1.0, 1974 Raleigh Sports, 1974 Schwinn Le Tour, 1981 Schwinn Super Le Tour, Surly Cross Check, 2021 Giant Talon 2
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 202 Post(s)
Liked 71 Times
in
60 Posts
Last year I switched from 23mm tires on box rims to some 25mm Continental 5000s on some 2019 Zipp 303 rims and enjoyed the added comfort but ended up with a few pinch flats that I didn't love. So I thought, why not keep going and throw some 28mm on? So I bought some and they measure almost identically to the 25s using my Park Tools DC-1!
25mm tire: 27.7mm wide
28mm tire: 28.01mm wide
As for the height, it was kind of hard to measure the inflated height of the tire alone so I used the clamp to measure from the inside of the rim to the top of the tire:
25mm tire: 70.74mm
28mm tire: 69.72mm
Has anyone else experienced this?
If I'm aiming for optimum tire pressure using https://axs.sram.com/guides/tire/pressure it looks like I'm using the same calculation for both, which just doesn't seem right.
25mm tire: 27.7mm wide
28mm tire: 28.01mm wide
As for the height, it was kind of hard to measure the inflated height of the tire alone so I used the clamp to measure from the inside of the rim to the top of the tire:
25mm tire: 70.74mm
28mm tire: 69.72mm
Has anyone else experienced this?
If I'm aiming for optimum tire pressure using https://axs.sram.com/guides/tire/pressure it looks like I'm using the same calculation for both, which just doesn't seem right.
03-22-21, 11:04 AM
#30
Faster!
Thread Starter
Join Date: Sep 2008
Location: NYC
Posts: 23
Bikes: Breezer Thunder, Breezer Venturi, Merlin Works CR 6/4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 1 Time
in
1 Post
Well, I'll be derned. I let my 28's sit around for another month with normal tire pressure and they did, indeed, get wider! I took some measurements today and got readings from 28.41 to 28.85! Interestingly, the 28's were slightly easier to put on the rim than the 25s so I think these are now my go-tos for the time being.
Likes For strayduck:
