Road Bike, Cycling Forums banner
1 - 20 of 51 Posts

·
Registered
Joined
·
5,830 Posts
Discussion Starter · #1 ·
Let's start a thread on actual tire widths, since manufacturers appear loath to make tires that actually conform to their specs. I bought a caliper measuring tool this weekend and have been measuring all of my tires, with some real surprises. Listed by brand, size and type of wheel:

- Vittoria Rubinos, 700x25, measure exactly 25 mm wide on Mavic Open Pro rims
- Vittoria Randonneur Hypers, 700x32, measure 34 mm wide on Velocity Dyad rims

- Continental GP 4 Seasons, 700x28, measure 26.5 mm wide on DT Swiss 465 rims

- Torelli open clinchers, 700x23, measure 24 mm wide on Mavic Open Pros

I was surprised by the Vittorias because the Rubinos always looked narrow to me for 25s, but they were spot on. The Hypers were actually fatter than billed.

The Conti GP 4 Seasons irk me. Why call a tire a 28 that measures only 26 mm wide? A bit of a scam, it seems to me. They are great tires but if I buy a 28, I want it to measure that wide.

I've got Michelin Pro2 Race 25s on another bike that I will measure later (at the shop), but I know that they run wide.
 

·
A wheelist
Joined
·
11,324 Posts
- Continental GP 4 Seasons, 700x28, measure 26.5 mm wide on DT Swiss 465 rims
The Conti GP 4 Seasons irk me. Why call a tire a 28 that measures only 26 mm wide? A bit of a scam, it seems to me. They are great tires but if I buy a 28, I want it to measure that wide.
I have some Conti 4-Season 28's also and I bought them because I wanted true 28's for dirt road riding. They measure just 26mm on my OP rims. I thought they were mis-labeled as other people have said theirs were wider. I just assumed it was because of my OP rim width.

My 25mm Vittoria Open Corsa Evo CX are actually wider than the 4-season - at 26.2mm. Go figure.

Tire width is a bit of a fuster-cluck due to varying rim widths and makers' dreams.
 

·
changingleaf
Joined
·
709 Posts
Many tires will stretch a little. I have found that the Hutchinson Atom Tubeless 23mm tire measures between 21 and 22. The Fusion Tubeless 23 does measure 23. The Intensive tubeless 25 measures 24 on an Alpha 340 rim with a 17mm inner width. Continental Top Contact 28mm measures 26 on the Alpha 340. The GP3000 23mm on a Mavic ksyrium is close to 23. Michelin Pro 3 23mm tire measures 25 on a Velocity A23 rim. The inner width the rim will make a big difference on tire width. Any tire that measures 23mm on a Ksyrium is going to be closer to 25 on an A23 or Zipp 303 Clincher.
 

·
Registered
Joined
·
176 Posts
All I can offer is regarding Vredestein Fortezza TriComps -
OpenPro rims, a 23 measures 23
HED Belgium C2 rims, a 23 measures 25 and a 25 measures 26.5. Still trying to decide if I like the 23 or the 25 better on the HEDs.
I do not own a caliper, but this is using a metal ruler looking directly down at the tire. I think it's pretty accurate.
 

·
Registered
Joined
·
55 Posts
Vittoria Open Corsa EVO CX 23 mm tires measured at 25 mm on A23 rims. My new Vittoria Open Corsa EVO CX 25 mm tires are measuring about 27.5 mm on the same rims. Veloflex Corsa 23 mm tires measured about 23.5 mm on the A23 rims and are measuring just a tad under 23 mm on Open Pro rims.
 

·
chamois creme addict
Joined
·
1,479 Posts
I have some Conti 4-Season 28's also and I bought them because I wanted true 28's for dirt road riding. They measure just 26mm on my OP rims. I thought they were mis-labeled as other people have said theirs were wider. I just assumed it was because of my OP rim width.

My 25mm Vittoria Open Corsa Evo CX are actually wider than the 4-season - at 26.2mm. Go figure.

Tire width is a bit of a fuster-cluck due to varying rim widths and makers' dreams.
I have Conti GP 4-Season in 700x25 that measure ~24mm on a 19-20mm rim (external). Conti GP4000S in 700x23 are almost identical at 23.9mm, but the same GP4000S in 700x25 are 26.5mm.

Conclusion, the GP 4-Season is undersized.
 

·
Registered
Joined
·
15 Posts
I have a pair of digital calipers:

On 2011 and 2012 HED. C2 clinchers that have an internal bead width of 17.5 mm - all three built by Prowheelbuilder.com:

Continental Limited Edition TT 23c - 24.5 mm at 110 psi rear and 105 psi front

Vittoria Open Pave EVO CG 24 c - 25.5 mm at 105 psi rear and 100 psi front

Continental 4000s 25c - 27.5 mm at 100 psi rear and 95 psi front

I have two pairs of Vittoria Open Corsa EVO CX 23c and 25c that will try next.

My Lynsky Helix OS has a 28 mm clearance at the rear chain stay so the 24c measuring at 25.5 mm may be the max width I can go. I am not sure if I could fit the new Vittoria Open Pave EVO CG 25c tires.

My Lynskey R330 has a 32 mm clearance at the rear chain stay so the Vittoria Open Pave EVO CG 27c tires could work.

My custom Parlee Z1 has a 32 mm clearance at the rear chain stay so I could go up to 28c tubular tires if I wanted. Currently, I am running Veloflex Carbon Black Tubular 23c, measuring 23 mm at 100 psi, up front and Veloflex Arrenberg Tubular 25c, measuring at 25 mm at 100 psi, at the rear.

Mark
 

·
Registered
Joined
·
59 Posts
Very confusing! I measure my tires as follows:
Mavic CXP 22 with Continental Ultra Sport 700 X 25 @ 100 PSI: 24mm wide
Blackset Race with Continental 4000s 700 X 23 @ 100 PSI: 25mm wide
What's going on? Does the second number relate to width (as most state), or to height (stated in one or two old posts). My wider-sounding 25 tires measure narrower than the 23's.
When we compare tire sizes, exactly what are we really comparing?
Bob
 

·
Premium Member
Joined
·
2,714 Posts
Anybody running the 25 or 28mm Schwalbe Ultremo ZX's on 23mm rims? What is the effective width?
 
1 - 20 of 51 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top