Back to 23mm

Everything about building wheels, glueing tubs, etc.
sufferfest69
Posts: 4
Joined: Wed Jul 24, 2013 2:54 am

by sufferfest69

It doesn't matter how fast a tire "feels"

The reality is that from multiple testing a wider tire at lower psi is faster. Period.

by Weenie


cmcdonnell
Posts: 270
Joined: Sun Aug 02, 2015 7:50 pm

by cmcdonnell

sufferfest69 wrote:It doesn't matter how fast a tire "feels"

The reality is that from multiple testing a wider tire at lower psi is faster. Period.


Not sure this is correct... I thought the facts were that a wider tyre at an equal pressure had a lower CRR so if you ran the wider tyre at a lower pressure you could have an equal or better CRR than a narrower tyre at that pressure allowing people who found narrow tyres uncomfortable to reduce pressures.
The wider tyre at a high pressure will offer a lower CRR than a wider tyre at a lower pressure.
The wider tyre at a lower pressure may have an equal CRR to narrower tyre at a higher pressure.
The narrower tyre will be more aerodynamic than the wider tyre as the tyre should be narrower than the widest point of the rim but i've seen little data objectively quantifying this.
To me a tyre that is inflated to 25mm (wide in my opinion) is about ideal wheter a clincher (probably a 23mm tyre on a 17C rim) or a 25mm tub.
Bianchi Oltre XR2 + Campagnolo Super Record 11 + Campagnolo Bora 50C
Litespeed T1 + Campagnolo Chorus 11 + Campagnolo Shamal Ultra

Alumen
Posts: 87
Joined: Tue Aug 18, 2015 1:47 pm

by Alumen

sufferfest69 wrote:It doesn't matter how fast a tire "feels"

The reality is that from multiple testing a wider tire at lower psi is faster. Period.


Not entirely true unfortunately...

From the tests you can read that a wider tire at lower psi is faster then a narrow tire at the same psi. But if you run your narrow tire on a higher pressure, the rolling resistance is more or less the same... And even worse, if you run a wider tire on a narrow rim, then it works even contra productive...

Have a look at the links I have added at my starting post.

Summarized..., only rims that are 17C wide and up benefit from the wider tires at lower pressure with slightly less rolling resistance. So basically with wider tires on wider rims you will experience "only" more comfort and some additional grip.

Reading all the pros and cons now, with my 15C Campy rims, I have concluded to go back to 23mm. I ride Conti's, so a 23mm Conti is approximately 25mm anyway so I still will enjoy a good level of comfort. However, I don't care about comfort to much, hence I ride a CAAD10 alloy frame.
CAAD 10 2015

fromtrektocolnago
Posts: 990
Joined: Sat Dec 07, 2013 10:15 pm

by fromtrektocolnago

23's, The truth is I never left you
All through my wild days
My mad existence
I kept my promise
Don't keep your distance
Colnago C-59 (Dura Ace)
Firefly(Ultegra)
Trek 5200(ultegra)

springs
Posts: 36
Joined: Tue Sep 25, 2012 6:07 pm

by springs

23's, The truth is I never left you
All through my wild days
My mad existence
I kept my promise
Don't keep your distance



I see what you did there.

User avatar
mpulsiv
Posts: 1021
Joined: Mon Mar 24, 2014 9:17 pm

by mpulsiv

It all comes down to rim profile http://enve.com/products/ses-4-5-ar
For those that like charts :)

Image
Racing is a three-dimensional high-speed chess game, involving hundreds of pieces on the board.

:arrow: CBA = Chronic Bike Addiction
:arrow: OCD = Obsessive Cycling Disorder

Marin
Posts: 2695
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

Shows nicely that all the aero snake oil don't matter at realistic yaw angles of 0 to 5°

prebsy
Posts: 762
Joined: Tue Oct 23, 2012 10:52 pm
Location: PHL

by prebsy

I would suggest everyone read the six part silca journal article about tire width, pressure and aerodynamics. Because of larger internals most aero rims can be run with a 23mm max tire to have the wheel perform any where near optimally. It's a balancing act between traction, aero, ability to run low enough to avoid "bouncing", and high enough to avoid pinching/bottoming out. I feel with tubeless I can hit that balance with a 23 for crits,rr,tt. With tubes I feel I need a 25 to balance the traction needed for crits and min pressure needed to avoid pinching.

Sent from my Nexus 5X using Tapatalk

User avatar
kgt
Posts: 6777
Joined: Sun Jun 18, 2006 10:29 am
Location: Athens, Greece

by kgt

Marin wrote:Shows nicely that all the aero snake oil don't matter at realistic yaw angles of 0 to 5°

+1

beswiss
Posts: 45
Joined: Sun Apr 08, 2012 2:02 pm
Contact:

by beswiss

There was a podcast on CyclingTips where they spoke with an engineer of Zipp about wider tires and lower PSI. It was pretty interesting on how the feeling of a high psi tricks the mind and gives a fast feeling due to the road buzz. Even for the engineers who knew the lower psi was faster, the higher one still felt faster.

Link to the podcast: https://cyclingtips.com/2016/08/cycling ... pressures/
C'dale SuperSix Evo Sram Red, Cube Agree GTC Race SL, Granville MTB XT

User avatar
Asteroid
Posts: 215
Joined: Tue Jul 26, 2016 8:43 pm
Location: Los Angeles, California

by Asteroid

My understanding is that track riders use 23 or smaller tires at high pressures.
Do they know something we don't know?

sufferfest69 wrote:It doesn't matter how fast a tire "feels"

The reality is that from multiple testing a wider tire at lower psi is faster. Period.
Oldbie

pdlpsher1
Posts: 1484
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

One has to keep in mind that the current crop of 23mm tires are really 25mm wide and would be labeled as 25mm a few years ago. The newer 25mm tires are really 28mm wide. So going back to a 23mm doesn't really say much about whether wider is good or bad.

sawyer
Posts: 4484
Joined: Fri Dec 15, 2006 7:45 pm
Location: Natovi Landing

by sawyer

Asteroid wrote:My understanding is that track riders use 23 or smaller tires at high pressures.
Do they know something we don't know?

sufferfest69 wrote:It doesn't matter how fast a tire "feels"

The reality is that from multiple testing a wider tire at lower psi is faster. Period.


They can ride very high pressures because the track surface is so smooth of course

And in those circumstances it makes sense to go for the lightest and most aero set up possible consistent with the rider's handling/grip preferences and the range of wheel width options. So it's not likely they've been on 17mm tyres, but 21mm for example on a narrow-ish rim at 150psi might well be a very fast set up for them in a way it wouldn't be on the road
----------------------------------------
Stiff, Light, Aero - Pick Three!! :thumbup:

User avatar
Calnago
Posts: 5765
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

pdlpsher1 wrote:One has to keep in mind that the current crop of 23mm tires are really 25mm wide and would be labeled as 25mm a few years ago. The newer 25mm tires are really 28mm wide. So going back to a 23mm doesn't really say much about whether wider is good or bad.

I don't think that's true at all. The reason they measure out wider these days is because they are being mounted on wider rims. A 23mm tire will measure larger on a wider rim than it will on a narrower one (talking about clinchers only here, as tubulars are contained in their own casing and rim width doesn't affect them the same way). If you really want to see how big a 25mm clincher can get, just mount it on a new ENVE front rim. It won't clear a lot of road forks these days. The thing is, while there are variations between manufacturers I think the sizing is still based on the tires being mounted on "normal" rim with a 15mm internal width. Mount them in bigger rims and they expand accordingly.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

by Weenie


fromtrektocolnago
Posts: 990
Joined: Sat Dec 07, 2013 10:15 pm

by fromtrektocolnago

keep hearing that michelin 23's ride wider than other 23's
Colnago C-59 (Dura Ace)
Firefly(Ultegra)
Trek 5200(ultegra)

Post Reply
  • Similar Topics
    Replies
    Views
    Last post