Tire width and pressure for feather light riders

Discuss light weight issues concerning road bikes & parts.
cmcdonnell
Posts: 277
Joined: Sun Aug 02, 2015 7:50 pm

by cmcdonnell

My take:
I'm 126lbs (+/-4lbs)
I do not like 25mm tyres on my summer bike. I see no benefits. I'm faster with 23mm tyres on the roads near me which are mostly good on the bigger roads and a bit patch on side roads, but I tend to ride on better roads. Never wanted more comfort. Started riding on 21mm's and when I went to 23mm's I instantly preferred them. Tried 25mm and for me they did not roll better and offered no more comfort to me. Didn't like the cornering and to be honest I never had issues with comfort on 23mm.
With tyre pressure it depends entirely on the tyres/rims.
On my Campagnolo Bora Clinchers (17mm inner width) I had been using Conti GP4000 II's at 90F 95R (25.1 real width) which felt fine. Grippy, comfortable and fast. Tried Michelin Power Competitions (24.4mm real width) but did not like them as they eitehr felt too hard or sloppy depending on the pressure and I had 3 blow outs. Recently switched to Specialized Turbo Cottons and love them, but I did have to run them at a higher pressure, 105F 110R (25.0 real width). Funny thing is that they are more comfortable the the Conti's at a higher pressure.
Bianchi Oltre XR2 + Campagnolo Super Record 11 + Campagnolo Bora 50C
Litespeed T1 + Campagnolo Chorus 11 + Campagnolo Shamal Ultra

by Weenie


Kaboom
Posts: 118
Joined: Wed Mar 22, 2017 3:53 pm

by Kaboom

compared to you guys I'm not a lightweight by any means at 69kg, so around 150lbs, and I recently switched from 23c to 25c
I'd always ridden 23c clinchers and switched to 23c tubies. Absolutely loved them from the first moment i tried them. Then I got a flat and since they were already somewhat worn I replaced them with exactly the same tire, Vittoria Corsa Evo CXIIIs, in 25c because everyone was raving about the fatter tires... And they are nice but I'm not convinced.
Sure, they're more comfy when you run them at 5.5 bar, so 80 psi, but at that pressure the bike just feels wrong. It feels wooden, dead, there's plenty of grip but you're never quite sure what kind of road you're riding on. I loved the 23c at 110psi because even though they beat you up after a hundred miles, they felt racey as hell and the bike just jumped at the slightest input.
I'm halfway through the 25cs and I'm not at all sure they're gonna make it all the way before i through another set of 23c on there...

Also the 100g weight penalty certainly wasn't fun, and significantly higher than I expected.

darnellrm
Posts: 215
Joined: Thu Sep 10, 2009 1:06 pm
Location: NC, USA

by darnellrm

Wow! 25mm Corsa Evo CXIII's are 100g heavier than 23mm's?

Delorre
Posts: 961
Joined: Sat May 24, 2014 12:09 pm

by Delorre

Kaboom wrote:compared to you guys I'm not a lightweight by any means at 69kg, so around 150lbs, and I recently switched from 23c to 25c
I'd always ridden 23c clinchers and switched to 23c tubies. Absolutely loved them from the first moment i tried them. Then I got a flat and since they were already somewhat worn I replaced them with exactly the same tire, Vittoria Corsa Evo CXIIIs, in 25c because everyone was raving about the fatter tires... And they are nice but I'm not convinced.
Sure, they're more comfy when you run them at 5.5 bar, so 80 psi, but at that pressure the bike just feels wrong. It feels wooden, dead, there's plenty of grip but you're never quite sure what kind of road you're riding on. I loved the 23c at 110psi because even though they beat you up after a hundred miles, they felt racey as hell and the bike just jumped at the slightest input.
I'm halfway through the 25cs and I'm not at all sure they're gonna make it all the way before i through another set of 23c on there...

Also the 100g weight penalty certainly wasn't fun, and significantly higher than I expected.


Being the same weight as you, and knowing that those 25mm tubies are true 25mm's, I would raise the pressure a bit. Vittorias are nown to remain very supple, even at higer pressures. I run my Michelin Comp 25's (27,5mm real) at 90psi. If i go lower, the bike becomes slighish, soft and somewhat slower. On very good roads, I would run them at 100psi. But i'm with you that 100gr penalty on the seat is really felt. When I put 28mm conti 4000s (275gr) on my Canyon, coming from 25mm 4000s (around 220gr), that was a massive differerence in sense of responsiveness and accelaration. Not slower on the flat's and when on speed, but in every other situation, the bike felt slower and a lot more heavy!! But what a pease of mind, even on gravel roads and (not too bad) single tracks.

So, to the OP, at your weight, I would keep running 23's on wide rims with just enough pressure in the tyres to prevent a too 'soft' feel.

sanrensho
Posts: 410
Joined: Tue Aug 02, 2011 5:54 pm

by sanrensho

Another data point, 120 lb rider. Riding front 25mm, rear 23mm that will be switched to 25mm eventually.

Front: Vittoria Evo CX III 25c tub 80 psi
Rear: Veloflex Carbon 23c tub 85 psi

On clinchers front/rear Vittoria 25c tires w/latex tubes, I typically ran 90/95 or 95/100 psi.

Kaboom
Posts: 118
Joined: Wed Mar 22, 2017 3:53 pm

by Kaboom

Delorre wrote:Being the same weight as you, and knowing that those 25mm tubies are true 25mm's, I would raise the pressure a bit. Vittorias are nown to remain very supple, even at higer pressures. I run my Michelin Comp 25's (27,5mm real) at 90psi. If i go lower, the bike becomes slighish, soft and somewhat slower. On very good roads, I would run them at 100psi. But i'm with you that 100gr penalty on the seat is really felt. When I put 28mm conti 4000s (275gr) on my Canyon, coming from 25mm 4000s (around 220gr), that was a massive differerence in sense of responsiveness and accelaration. Not slower on the flat's and when on speed, but in every other situation, the bike felt slower and a lot more heavy!! But what a pease of mind, even on gravel roads and (not too bad) single tracks.

So, to the OP, at your weight, I would keep running 23's on wide rims with just enough pressure in the tyres to prevent a too 'soft' feel.


I've tried a range of pressures on the 25s and i've settled on 100psi for the rear and 95 for the front. And yeah, the tires don't feel as floppy as they do at around 80-85, but at a full 7 bar they really aren't any more comfy than the 23's either, and you are still lugging the weight penalty and the increased radius around (I believe, though i'm not entirely certain, that a fatter tire with a bigger radius is slower to turn in because the contact point has to move sideways more than on a narrower tire when you lean the bike. Again, I could be wrong)

Your perceptions about the tires match mine almost exactly. As you said, once you're up to speed you can't really feel any difference besides the comfort (if you're running lower pressures...), but the moment you have to accelerate, throw the bike quickly into a turn, climb out of the saddle etc, they just don't feel quite as sharp and nimble a tool as the narrower tires.

Also something I didn't mention before, I think the feeling at the edge of grip is very different between the two sizes. Whilst the 23's start getting skittish and sort of jumping around when you're pushing them too far in a turn, the feeling I get with the 25s is sorta like they were "folding over" themselves. I find this to be the case at all reasonable pressures and alarmingly so at anything below 85psi in the front tire. I like the "skip and jump" kind of warning a lot better than the "folding over" kind.

I'm lucky in that I live in Mallorca and most of the roads here are great and I don't really need the extra comfort, so It's gonna be back to 23mm at 110psi front and rear for me real soon.

3Pio
Posts: 868
Joined: Wed Mar 09, 2016 7:13 pm

by 3Pio

To dont open a new thread, i'll ask here..

I just installed Continental 4000 SII 23mm on my Shamal Ultra 2014 (15C version i guess). The tires i rode almost whole season was Vittoria Corsa G+ 25mm. The pressure i used in Vittoria was 7.4 Bar in the front, 7.9 Bar in the rear. Im 74 kg in this moment, and not that good roads. Like to climb.

So what pressure should be ideal for the Conti 4000 SII 23 mm, for my weight and riding conditions?

AJS914
Posts: 2051
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

I ride 23mm Conti GP4000s at 100psi (6.9 bar) and I'm heavier than you. I think you are using too much pressure on the Vittorias.

Also, I only pump up my Contis once a week so by the end of the week they are around 85/90 psi and don't feel quite as sharp.

3Pio
Posts: 868
Joined: Wed Mar 09, 2016 7:13 pm

by 3Pio

AJS914 wrote:I ride 23mm Conti GP4000s at 100psi (6.9 bar) and I'm heavier than you. I think you are using too much pressure on the Vittorias.

Also, I only pump up my Contis once a week so by the end of the week they are around 85/90 psi and don't feel quite as sharp.


I like the feeling of a firmer tires. If we talk about comfort, they are fine even on very long distance rides.. I planned to try 4000 SII with 100psi on front and 105 rear, but i'll go lower.

BTW, what is ur weight?

p.s. i also have Continental 4 Season in 25mm. I use there 6.5 bar or 94 psi) and im satisfied with that pressure there

AJS914
Posts: 2051
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

I'm 90kg.

3Pio
Posts: 868
Joined: Wed Mar 09, 2016 7:13 pm

by 3Pio

AJS914 wrote:I'm 90kg.



I just get back from test ride with 6.5 in the front, and 7.0 in the rear. 25 km, with 500 meteres climb. I'll experiment a little bit more, but probably im somehwere near in term of pressure.. Thanks a lot for ur post

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hmai18
Posts: 652
Joined: Mon May 15, 2006 12:19 am
Location: Vancouver, BC, Canada.

by hmai18

130-135lbs, depending on how much ice cream I've had during the week.

28mm Schwalbe One, latex tubes, on 19mm internal rims. 50 front, 60 rear. Any lower and they get noticeably squishy during out of saddle efforts. I'll go as high as 55/65 if I know I'm going to be on near-perfect tarmac, but 50/60 seems to be my sweet spot.

TobinHatesYou
Posts: 1378
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

135lbs, 28mm Pro Ones 60/65psi is pretty supple already. For PR attempts, I go 90/98. On 25mm Zipp RT25s I run 73/80. The Zipps can bleed air out between the bead and rim if the tire pressure gets below 60psi so I keep it higher.

glepore
Posts: 1119
Joined: Thu Mar 28, 2013 4:42 pm
Location: Pa USA

by glepore

130, 25 mm Vitt's (actual 28) at 80. Have not had a non thorn flat in 2 years. A little firm, yes, but they corner like fat racecar tires. Initial turn in a little slowish, but on a supersix, that's not a liability.
Cysco Ti custom Campy SR mechanical (6.9);Cannondale SS Evo Di2 7970 (5.79); Willier Cento Uno Air Di2 9070 (7.0); C40 Mk2 DA 7800 ; Anvil Custom steel Etap;1996 Colnago Technos Record

by Weenie


dmp
Posts: 334
Joined: Fri May 08, 2009 8:31 pm
Location: Denver

by dmp

127-129 lbs (58-59kg), I have never tried 25's. I am on 23mm Michelin Pro4 Service Course or Power Race on Stan's 340 rims (actual measurement when inflated is 24.5mm) inflated at 80psi front, 85psi rear. They feel great and corner very well, but I don't have much of a standard of comparison, since I've been running these or their predecessors for several years. I was on tubs before, which (if memory serves) were perhaps better, but without a head to head comparison its hard to say for sure.

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