Tire talk 23 vs 25

Discuss light weight issues concerning road bikes & parts.
TobinHatesYou
Posts: 4310
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Greatestalltime wrote:
Fri Aug 16, 2019 8:05 pm

What I’m taking from that is that 23c is faster(thought I read that which contradicts a lot of what I’ve read) and if comfort isn’t one of your factors go with 23c.

...pinch-flat protection, cornering grip, etc. I can't imagine riding/racing on 23s. I've flatted out of two road races on 25s after hitting potholes and have yet to flat on my 28s and now 30s.

by Weenie


Greatestalltime
Posts: 64
Joined: Sun Jul 02, 2017 12:47 pm

by Greatestalltime

AJS914 wrote:
petromyzon wrote:
Thu Aug 15, 2019 10:43 am
Tyre pressure choice is very personal but there is good evidence to suggest that feeling fast is not the same as being fast, and unless you are 200 pounds 120 psi belongs on the velodrome
Even if you are 200 pounds you don't need 120psi. I'm a 200 pounder and I ride 80psi on 25mm GP4000 (really a 27mm tire). If I were on smoother roads I'd go to 90psi.

OP, try 90-100psi if you are on smooth roads. OP consult this this blog post. You want your pressure below the breakpoint. 120psi is never faster on the road.

https://blog.silca.cc/part-4b-rolling-r ... -impedance
I have tried it, but I’ll try it again. I realize no one rides at this psi. It’s just what feels better to me. I really feel like I’m “sloshing” around when it drops down around 100. I feel(which I realize is likely wrong) like I’m on a frame that’s flexing when the pressure goes down. I’m around 185lbs.

I also recently broke a Ultegra 8000 and dura Ace 9000 crank at the exact same spot. I wonder if these high pressures could be a factor in any way?? It feels more stiff. Is it too stiff? Or is my perceived feeling of stiffness (which I like) not what I’m feeling?


Sent from my iPhone using Tapatalk

Greatestalltime
Posts: 64
Joined: Sun Jul 02, 2017 12:47 pm

by Greatestalltime

TobinHatesYou wrote:
Greatestalltime wrote:
Fri Aug 16, 2019 8:05 pm

What I’m taking from that is that 23c is faster(thought I read that which contradicts a lot of what I’ve read) and if comfort isn’t one of your factors go with 23c.

...pinch-flat protection, cornering grip, etc. I can't imagine riding/racing on 23s. I've flatted out of two road races on 25s after hitting potholes and have yet to flat on my 28s and now 30s.
But...are your rims wider than 15c? That’s my issue. I feel I may be losing performance benefits on my 15c c24 and c40 and that article seems to confirm that.

I totally agree about the potholes with 25mm. That was the initial reason I stayed 25mm for so long after switching (2-3 years ago). I’m only now wondering if I should switch back.


Sent from my iPhone using Tapatalk
Last edited by Greatestalltime on Sat Aug 17, 2019 11:59 am, edited 1 time in total.

3Pio
Posts: 1294
Joined: Wed Mar 09, 2016 7:13 pm

by 3Pio

Greatestalltime wrote:
Sat Aug 17, 2019 11:59 am
TobinHatesYou wrote:
Greatestalltime wrote:
Fri Aug 16, 2019 8:05 pm

What I’m taking from that is that 23c is faster(thought I read that which contradicts a lot of what I’ve read) and if comfort isn’t one of your factors go with 23c.

...pinch-flat protection, cornering grip, etc. I can't imagine riding/racing on 23s. I've flatted out of two road races on 25s after hitting potholes and have yet to flat on my 28s and now 30s.
But...are your rims wider than 15c? That’s my issue. I feel I may be losing any performance benefits on my 15c c24 and c40.

I totally agree about the potholes with 25mm. That was the initial reason I stayed 25mm for so long after switching (2-3 years ago). I’m only now wondering if I should switch back.


Sent from my iPhone using Tapatalk

I ride 23mm on Shamals Ultra (considered as Harsh Wheelset), on CAAD12 Frameset (Alloy), with Alloy HandleBar (Deda Zero100).. Roads here are really bad in any way... Never have comfort issuess and as i mentioned i rode on this setup few >200km rides in last period (this season i have 8 or 9 that kind of rides, and half of them on Caad12 with this setup i mentioned...)

As i mentioned i never feel that i need more comfort, never damage the tire from potholes (which are plenty here, ok once i hit the rock on the road which i did not see, and that made both of my tires flat.. I was on 25mm 4season then) ... When i was riding 25mm Corsa G+ on 15C rims, i did not feel that i benefit from extra comfort, but i had negative feeling from the bulb shape... Same feeling my friend using 25mm Continental 4000 SII on 15C rims.... But i really love responsive feeling,good control, reactivity etc, that im getting from 23mm...

I will continue using 23mm 4000 SII on 15C rims.. If i need to buy 5000 Continental, i will first measure on rims and decide if ill go 23 or 25 (if 25 mm 5000 is similar as 23mm 4000 then will go that way.. If its much wider/bigger, then again 23mm)

JerryLook
Posts: 293
Joined: Thu Dec 07, 2017 2:18 am

by JerryLook

On my 13c and 15c wheelsets I prefer the handling of 20mm tire in the front and 23mm in the rear. 23mm front and back wasn’t bad either. With latex tubes the comfort wasn’t bad.
25mm tires on those wheels didn’t handle as well IMO.
On the same bike I put 19c wheels eventually with 25mm tires (27mm measured). But I didn’t do for comfort, I did it so I could ride on paved roads and some gravel roads.
2010 Orbea Opal 54cm
5.97kg

User avatar
Calnago
Posts: 8608
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

@JerryLook: if you want a really sublime ride from clinchers on your standard width rims (~20-21mm external, ~15mm internal), I’d say give the 24mm Specialized Turbo Cotton (clincher) a try. I agree about putting a 25mm Conti 4000sii on those rims, ending up kinda big and tall and not as nice handling. Didn’t care for them on my Campy Neutrons.
With clinchers and so many different rim widths these days, it’s hard to know exactly how big your overall tire will measure and even harder to determine what the internal air volume will be since that will somewhat depend on the internal rim bed profile as well, which will have no effect on the outside measurement. Basically if you change internal rim width, say from 15mm to 17mm then you can add 2mm to the size right off the bat since the effective cross sectional circumference has just been increased by 2mm. Throw that same tire on a 19mm internal width rim, and expect 4mm difference over what it might be on a 15mm internal width rim. I think sizing is really in a state of flux right now. Look at the new Conti 5000’s... they seem to be sizing more in line with an assumption that internal rim widths on average have increased in recent years.
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

CrankyCarbon
Posts: 66
Joined: Tue Aug 13, 2019 1:15 pm

by CrankyCarbon

My tried and true "everyday" wheels - 2001 Campy Rec 32h hubs, 15g Alpina oval spokes 3x on Mavic Open Pro 15C I use 23mm at about 105 psi.
I also use about 105 psi on my 23mm tubulars on Fulcrum 50m XLRs. Newer wheel are Fulcrum Competiziones 17C with 25mm

Last year I got a slow flat on my rear tub (Fulcrum 50mm XLRs) and the rear tire started oscillating (for lack of better word) side to side. It made one seem as though the rear of the bike was flexing side to side, although even while coasting.

I've found the same feeling when I accidentally don't fill up the rear tire on my clinchers to my preferred tire pressure. The rear tire can oscillate. Its' like what you see cars with flat tires driving down the road. The tire rolls left to right, back and forth. Even 3 lbs psi makes a world of a difference to me.

Of course, several weeks ago I had a rear tire delaminate on Vittoria Corsa Open clinchers. That was a really weird feeling. It was like you had a really bad tubular flat but it rolled straight perfectly fine in a way but the rear would jump to the side especially during a corner. The tire had the middle strip a different color so it was easy to spot the "S" shape in the tread from the delimination.

Of course your body weight, your front/rear weight distribution can affect your feeling of the tires pushing, or dragging around corners. A few more psi and they'll feel completely different.

In the old days, clinchers, due to the thinner rims, were very bulbous shaped. It felt like you were falling off of a cliff from the highs of the tire to the sides during a steep corner. Tubulars never had that issue as they maintained mostly a round shape. Nowadays with the shorter sidewall clinchers, and wider rims they are able to have a better consistent arc shape.

Methodical
Posts: 98
Joined: Sat Mar 03, 2018 11:40 pm

by Methodical

Greatestalltime wrote:
Wed Aug 14, 2019 8:09 pm
CrankyCarbon wrote:There's been a lot written about this.
23mm seems best for speed/comfort on 15C rims (the inside diameter).
25mm seems improves the comfort on 17C rims
but 25 on 15c is improved comfort but worse speed/handling as you are mentioning.

this excludes aero, pressures, etc.
I run 23mm Vittoria Corsa on Mavic Open Pros, which are 15C. I also only run 23mm on my older rims/wheels.
and I run 25mm Vittoria Corsa G+ on Fulcrum Competizione 17C
So those tests don’t have 25mm on 15c rims? Thanks I guess I missed that.

So I’m thinking I will go back to 23 until I upgrade wheels. I never thought the 23 were uncomfortable as actually like high pressure on either tires size-like 120psi plus


Sent from my iPhone using Tapatalk
I used to be the same, but once I tried the 25mm tires and dropped the pressure from 120psi down to 80f/90r, I was a convert. Those 23s at high pressure were just harsh. Back in the day (80s) I always wanted the skinniest tires I could get on the rim. I always thought the harder the faster. I now see things differently. Try the 25s at lower pressure to see how you like them since you already have them on - testing for yourself is always better than asking the interweb folks.

Just One Man's Opinion...
"Never be afraid to try something new. Remember, amateurs built the Ark, professionals built the Titanic"

Trek Emonda SLR (Rage Red) - 6.27kg
'12 Trek Madone (Black) - 6.96kg
Fujee Espree (Maroon) - 11.02kg

CrankyCarbon
Posts: 66
Joined: Tue Aug 13, 2019 1:15 pm

by CrankyCarbon

Methodical wrote:
Fri Aug 23, 2019 9:22 pm
Greatestalltime wrote:
Wed Aug 14, 2019 8:09 pm
CrankyCarbon wrote:There's been a lot written about this.
23mm seems best for speed/comfort on 15C rims (the inside diameter).
25mm seems improves the comfort on 17C rims
but 25 on 15c is improved comfort but worse speed/handling as you are mentioning.

this excludes aero, pressures, etc.
I run 23mm Vittoria Corsa on Mavic Open Pros, which are 15C. I also only run 23mm on my older rims/wheels.
and I run 25mm Vittoria Corsa G+ on Fulcrum Competizione 17C
So those tests don’t have 25mm on 15c rims? Thanks I guess I missed that.

So I’m thinking I will go back to 23 until I upgrade wheels. I never thought the 23 were uncomfortable as actually like high pressure on either tires size-like 120psi plus


Sent from my iPhone using Tapatalk
I used to be the same, but once I tried the 25mm tires and dropped the pressure from 120psi down to 80f/90r, I was a convert. Those 23s at high pressure were just harsh. Back in the day (80s) I always wanted the skinniest tires I could get on the rim. I always thought the harder the faster. I now see things differently. Try the 25s at lower pressure to see how you like them since you already have them on - testing for yourself is always better than asking the interweb folks.

Just One Man's Opinion...
Back in the 80s when I weighed 132lbs/59.8kilos I used to ride Vittoria 21.5mm tubulars all the time. I always did 95psi in the wet and 110 max in the dry on 20mm or 21.5mm wide tub rims (great for fast crits). I never liked them rock hard. Now I'll run clinchers 23mm/C15 rims at 105psi and 25mm/C17 at 90 (or less for a cushy, casual ride) even though the Corsa sidewalls states minimum 87psi. I run my 23mm tubular on my 20mm Fulcrum 50mm XLRs at 105 to 110psi.

Even back in the late 90s after the Vittoria Georgia/Florida clinchers (large bulb) I got a hold of some japanese made short sidewalled clinchers and ran them on my Campy box Clincher rims. They were totally awesome. Vittoria then had some short sidewalled clinchers but with horrible thick touring treads.

Of course going back to the original Specialized Turbo S clinchers on 19mm Araya aero rims, I had those pumped up to 120psi as they bulbed big and the psi kept them from flipping to the side too much. But they felt like you were falling off of a cliff on turns coming off that bulb top, which is why I always raced on tubulars for nice smooth transitions.

Ahh .. how times have changed.

Greatestalltime
Posts: 64
Joined: Sun Jul 02, 2017 12:47 pm

by Greatestalltime

I’ve tried the 25’s extensively with lower pressure and don’t like the “squirmy” feeling. I’d guess I need wider rims to make that work for me.

I’ve bought 23’s and plan to switch back when these wear out.


Sent from my iPhone using Tapatalk

Post Reply
  • Similar Topics
    Replies
    Views
    Last post