anybody go to 28mm tires, and NOT like the switch?

Discuss light weight issues concerning road bikes & parts.
spdntrxi
Posts: 2666
Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

Campervan wrote:
Mon Apr 01, 2019 1:18 pm
spdntrxi wrote:
Thu Mar 28, 2019 3:27 pm
my 28's are schwalbe pro ones... normally I ride turbo cotton in 24 and 26. You can feel the difference easy..it's plush. Nothing like my WTB Byways @ 650x47..but still.
Would you think the 28 Schwalbe pro one's (tubeless) would be much more comfy than a S-works turbo 26mm?
well they ballon pass 30mm and at 60-65psi.. yes.

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Campervan
Posts: 51
Joined: Thu Nov 29, 2018 7:45 pm

by Campervan

spdntrxi wrote:
Mon Apr 01, 2019 3:07 pm
Campervan wrote:
Mon Apr 01, 2019 1:18 pm
spdntrxi wrote:
Thu Mar 28, 2019 3:27 pm
my 28's are schwalbe pro ones... normally I ride turbo cotton in 24 and 26. You can feel the difference easy..it's plush. Nothing like my WTB Byways @ 650x47..but still.
Would you think the 28 Schwalbe pro one's (tubeless) would be much more comfy than a S-works turbo 26mm?
well they ballon pass 30mm and at 60-65psi.. yes.
I'm sure the ne wVenge can take up to 32mm...
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spdntrxi
Posts: 2666
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by spdntrxi

Campervan wrote:
Mon Apr 01, 2019 3:48 pm
spdntrxi wrote:
Mon Apr 01, 2019 3:07 pm
Campervan wrote:
Mon Apr 01, 2019 1:18 pm
spdntrxi wrote:
Thu Mar 28, 2019 3:27 pm
my 28's are schwalbe pro ones... normally I ride turbo cotton in 24 and 26. You can feel the difference easy..it's plush. Nothing like my WTB Byways @ 650x47..but still.
Would you think the 28 Schwalbe pro one's (tubeless) would be much more comfy than a S-works turbo 26mm?
well they ballon pass 30mm and at 60-65psi.. yes.
I'm sure the ne wVenge can take up to 32mm...
actually measured 32.. likely yes.


Campervan
Posts: 51
Joined: Thu Nov 29, 2018 7:45 pm

by Campervan

mhrzip wrote:
Mon Apr 01, 2019 4:12 pm
https://www.bicyclerollingresistance.co ... comparison

28 mm here
So there is a large difference between the Schwalbe Pro One and the S-works. Far more than I thought.
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C36
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by C36

RocketRacing wrote:
C36 wrote:
Sat Mar 30, 2019 3:00 am
Has any other study been conducted on the topic?
I for sure know that Michelin did test tires over different surfaces for like forever (the axial at least) but never recall anything published confirming silca “blog” whom science appeared very doubtful at times (recall the wheel/tire vertical stiffness that had little solid ground)


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Tom anhault came up with the same findings independantly. Also... the guys on mountain bikes intuitively have known the same data without actual formally studying it... forever. To a lesser degree, same with race car drivers (but that is a bit different, but “higher is fastest, or lowest is fastest” is the reality they discovered is not true). The rougher the surface, the lower the pressures... the faster you are. But not too low. The trick is to find that sweet spot for every rider/condition.

What is the fastest tire/wheel combo? It is influenced by many factors:
- Wheel weight
- wheel shape (aero)
- mounted tire width
- tire pressure
- tire pressure effects mounted width
- tire width effects aero performance (too wide is bad)
- tire construction (rolling resistance)
- road surface (how rough)

The silca “blog” is worth the read... i say it is essential reading. As is the related “marginal gains podcast.” Josh was a big part of the zipp wheel development process. He also has been and advisor for many pro tour teams (currently EF, prevously with bora/sagan, wiggins 1hr record, etc). When the smartest person in the room speaks, we become smarter by listening.

Also, check out slowtwitch, as it is full of people in competition, many of whom are on the cutting edge of “best practices”. I was learning about tire pressures over there (pre reading the five part silca articles on the topic)... and i started quoting bike rolling resistance numbers (good source, but does not take into account impedance losses from rough surfaces), and someone basically told me... “keep your pressures up if you wish, i just hope you are conpeting in my age group.”
I don’t have the entire article but isn’t last Tour magazine not showing this ?
The 25mm has always lower RR than the 28mm and regardless of slick or rough surface, higher pressure also lead to lower RT. If anyone has the complete article, am I missing anything?
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Last edited by C36 on Wed Apr 10, 2019 9:14 am, edited 1 time in total.

Ettore
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by Ettore

28mm Pro One Tubeless here. Not a single downside. Fast, puncture proof, grippy enough, all I need.

guyc
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by guyc

I’ll take the extra comfort and ride quality over a 1w saving. All. Day. Long.

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C36
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by C36

Ettore wrote:28mm Pro One Tubeless here. Not a single downside. Fast, puncture proof, grippy enough, all I need.

For the first time I read the complete test of the GP5000 and it’s interesting to see that at iso-comfort (same deformation) the 23, the 25 and the 28mm have the same rolling resistance.
Image
That kind of explain why despite being very sensitive to all material changes, I never felt any real comfort gain with the 25mm and was always doubtful on all the comfort claims.

So the wider tires are :
- heavier,
- sluggish
- don’t roll better at equivalent “comfort pressure”
- have more aero drag...
+ They do have more grip

In case it was needed, it finished convincing me to remain on 23 / 25mm depending of the wheels.

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Ettore
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by Ettore

C36 wrote:
Wed Apr 10, 2019 11:21 am
Ettore wrote:28mm Pro One Tubeless here. Not a single downside. Fast, puncture proof, grippy enough, all I need.

For the first time I read the complete test of the GP5000 and it’s interesting to see that at iso-comfort (same deformation) the 23, the 25 and the 28mm have the same rolling resistance.
Image
That kind of explain why despite being very sensitive to all material changes, I never felt any real comfort gain with the 25mm and was always doubtful on all the comfort claims.

So the wider tires are :
- heavier,
- sluggish
- don’t roll better at equivalent “comfort pressure”
- have more aero drag...
+ They do have more grip

In case it was needed, it finished convincing me to remain on 23 / 25mm depending of the wheels.

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You can ride them at lower pressures which significantly decreases fatiguing through road buzz, which is the whole point of going up in size. Meaning all of the downsides you describe are compensated with retaining energy and thus power.

mrlobber
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by mrlobber

Ettore wrote:
Wed Apr 10, 2019 12:25 pm
You can ride them at lower pressures which significantly decreases fatiguing through road buzz, which is the whole point of going up in size. Meaning all of the downsides you describe are compensated with retaining energy and thus power.
The "significant decrease of fatigue from road buzz" is anecdotal evidence at best. Show me at least one controlled trial where it would be measured that provided you are on optimal pressures for different tire sizes, after certain (long!) distance on average road surface (not talking about cobbles here) you're able to put out more power because you're running 25mm vs 23mm tyres, or, even less difference: 28 vs 25. I don't think it is even realistic to measure it, let alone claim that objective losses in rolling resistance (albeit small, of course, compared to total power output) are compensated by less perceived fatigue to the degree that at the end of the ride you're consistenly putting out 5 to 10W more. Even more so for longer rides, as it is pure average mathematics: if you lose, say, 2 watts due to rolling resistance for 4 hours, you'd need to put extra 8 watts in the 4th hour to fully compensate the whole ride.

Edit: on topic, I find little benefits from 28mm (real width) tyres, although it might be I puncture them a little less than smaller widths - but again, no reliable statistics, only my n=1 observations. But that might be due to fact I don't run any 23mm clinchers, tubs only, and generally tend to avoid bad roads if I can.
Last edited by mrlobber on Wed Apr 10, 2019 2:07 pm, edited 1 time in total.
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morrisond
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Joined: Thu Mar 25, 2004 8:34 pm

by morrisond

To me the biggest benefit of wider tires is Safety.

If you live in an Area with perfect Asphalt - no sewer grates and paved shoulders everywhere - then small tires make a lot of sense (I went to Maui recently on a trip and took my Gravel Bike with 38mm Compass Tires - not needed at all - 25mm would have been fine)

However if you live in an area where that isn't true (Like me - I live in Southern Ontario) then wider tires bring a lot of safety - not as lible to fall into cracks you don't see - sewer grates become a lot less of an issue (Especially 32's - I'm currently on GP5's) - if you have to go onto a soft gravel shoulder - a lot more likely to not fall.

And most importantly as you can run them at a lot lower pressures - way more comfortable over things like Frost cracks/heaves in the Road.

I find them a lot faster because of this - you don't have to constantly lay off the power and wait for the hit like you do with 23's - you just keep the power down and roll right over.

In my experience they are way less fatiging in my area - and especially less mentally fatigeing as you don't have to be as aware of crappy road ahead of you.

mrlobber
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by mrlobber

Well, for city suburban commuting I wish I hadn't sold my hardtail MTB - even CX 35mm seem to be "too hard" at times :)
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Nefarious86
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by Nefarious86

Training tyres are the 25/28 Roubaix on a 21mm internal rim. At 84kg all I can say is 65psi and 32mm acutal width is great fun tipping into hairpins and bunnyhoping random faults in the road.

I run 24mm turbo cottons at 75/80 on my 303s and have 0 issues.

As for being "slow" some.of my best Bps including long decents and flat fast segments have been done on training wheels at comparable Watts... Go figure. Image

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AJS914
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by AJS914

Having just moved to a farming area with poor roads, I wish I could fit wider rubber on my Colnago. I'm a little jealous of a buddy who has a Domane and can run 30mm tires. I used to always run 90/95psi on 23mm GP4000s. I've since squeezed 25mm GP4000s (measure 27mm) into my C59 and run them at 75/80psi.

My gut feeling is that drum roller testing doesn't accurately measure how much power gets zapped out of your forward momentum on bumpy, rough roads.

by Weenie


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