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

Discuss light weight issues concerning road bikes & parts.
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Calnago
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by Calnago

Bigger contact patches mean more rolling resistance, not less. More surface area from each side in contact with each other. Hence more friction,, no? Add more weight and that rolling resistance just increases, same as if you’re cranking up the tension on a roller type trainer that your rear wheel is rolling against. I know which is slower for me going up a hill... and that’s a fat tire at low pressure.
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Imaking20
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by Imaking20

Calnago wrote:
Fri Jun 21, 2019 9:44 pm
Bigger contact patches mean more rolling resistance, not less.
I have not seen a single tire test that supports this statement. They tend to prove quite the opposite. The loss then is not in crr - it's about balancing the improved crr with the wider tire against the aerodynamic penalty. Tom Anhalt had a good couple of blogs about this.


For what it's worth, I'm not necessarily a giant tire supporter. I've ridden Arenbergs almost exclusively the last few years and only recently got to the point of being "ok" with the Ravens on my Wilier. Now I've got a set of 30mm Corsa Controls inbound to throw on a new bike with some generous tire clearance. And now after my maiden voyage on that bike, on Arenbergs, I'm again questioning how much "comfort" one really needs on a road bike?!?!
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Mr.Gib
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by Mr.Gib

Calnago wrote:
Fri Jun 21, 2019 9:44 pm
Bigger contact patches mean more rolling resistance, not less.
Data to support this?
There are roll down tests that show the opposite. It was on gravel. The softer the tire (so a bigger contact patch) the faster it rolled until nearly flat. Tarmac is just really smooth gravel. Well of course it's not, but it is likely the principle may still apply to some extent.
Imaking20 wrote:
Sat Jun 22, 2019 2:50 am
I'm again questioning how much "comfort" one really needs on a road bike?!?!
Well, the answer to that depends on the road, and your saddle, handlebar tape, and shoes, or alternately your ass, hands, and feet. Some of us can tolerate more punishment. I freaking hate shock from the road in any form. If I can get more comfort, I always go that route and it seems to be without any cost so why not.
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tymon_tm
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by tymon_tm

might be wrong, but isn;t it *all* about sidewalls - namely how much do they flex? if wider tires will flex less at sidewalls, their rolling resistance might be less. of course we're moving in a pretty narrow area - there's hardly a deal breaking difference between 23 and 28 tires. I imaginethe material and *right* pressure are much more important than the actual width
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Imaking20
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by Imaking20

Mr.Gib wrote:
Sat Jun 22, 2019 3:31 am
Imaking20 wrote:
Sat Jun 22, 2019 2:50 am
I'm again questioning how much "comfort" one really needs on a road bike?!?!
Well, the answer to that depends on the road, and your saddle, handlebar tape, and shoes, or alternately your ass, hands, and feet. Some of us can tolerate more punishment. I freaking hate shock from the road in any form. If I can get more comfort, I always go that route and it seems to be without any cost so why not.
Well, it was a rhetorical question.

Also there is definitely a cost for the wider tires. Aerodynamic penalty, weight penalty, change to handling characteristics and "bounciness". Weight is actually the only one of these costs I've never been super bothered by - but I've been bothered enough by the rest to be fairly resistant to larger tires. Even now, I'll put Arenbergs back on the Wilier when the wider tires wear out - because they seem to have a better rim:tire transition and I'm only trying the #superfat tires on the other bike because it's intended to be my "go slow" bike. The one I can ride around with the wife and not feel obligated to ride her off my wheel all the time because the bike needs me to...


Anywho, if you haven't seen Anhalt's blog about balancing rolling resistance against aerodynamic efficiency - I'd say it's definitely worth a read.

http://bikeblather.blogspot.com/2015/10 ... art-1.html
http://bikeblather.blogspot.com/2015/10 ... art-2.html

There's nothing to say any of this really makes an appreciable difference for the majority of us - but I think if one would like to argue on behalf of some of the science, they should be open to all of the science. Unless you're running a country... :|
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Mr.Gib
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by Mr.Gib

Imaking20 wrote:
Sat Jun 22, 2019 3:38 pm
Mr.Gib wrote:
Sat Jun 22, 2019 3:31 am
Imaking20 wrote:
Sat Jun 22, 2019 2:50 am
I'm again questioning how much "comfort" one really needs on a road bike?!?!
Well, the answer to that depends on the road, and your saddle, handlebar tape, and shoes, or alternately your ass, hands, and feet. Some of us can tolerate more punishment. I freaking hate shock from the road in any form. If I can get more comfort, I always go that route and it seems to be without any cost so why not.
Well, it was a rhetorical question.

Also there is definitely a cost for the wider tires. Aerodynamic penalty, weight penalty, change to handling characteristics and "bounciness".

There's nothing to say any of this really makes an appreciable difference for the majority of us - but I think if one would like to argue on behalf of some of the science, they should be open to all of the science. Unless you're running a country... :|
I guess whether or not there are costs depends on the application. Are you racing? And if you are racing, you are using an aero helmet with a face shield - aren't you? And aero clothes and shoe covers - right? So yeah, definitely don't won't to pass up any free speed. And when you are not racing what is the aerodynamic cost of 28mm vs 25mm? The cost of 40 grams per tire? Bounciness? I don't get bounciness unless a tire is way too soft, so not a factor. As low as 60 psi on 28mm - 32mm and no bounce. As for handling, I think more traction means better handling - can corner and descend faster. That's quantifiably better isn't it as opposed to "I don't like the way it feels".
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

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Calnago
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by Calnago

Hmm... I don't race, well... except for the occasional Cat 6 event. I certainly don't use an aero helmet with face shield. Aero clothes just make me look fat. And shoe covers are for girls. But I'm all about the ultimate ride quality of a nice road racing bike. Not to be confused with my touring bike. And for me, that means I like to feel the road... without any mushiness, yet soft enough to roll over smooth pavement nicely without any harshness or potential to bottom out if I happen to fly over the occasional minor pothole or speed bump. A tire similar to say a 25mm, give or take a millimeter or so, Arrenberg tubular fits that bill pretty perfectly for me, mounted on say a Campy Bora rim. Aerodynamic cost?... don't really care... as I said, I'm not racing, and even if I was, I probably wouldn't be overly concerned with it unless it was an all out time trial. For me it really is all about the "feel" and that combo of Arrenberg 25mm tubular on a Bora rim feels so right, to me. Even the 27mm Veloflex Vlanderens felt kind of vague at 80psi under my 200+lbs of Cat 6 beastliness. But tubulars do feel different than clinchers and I feel you can get away with a smaller width than a clincher. Clinchers have to be kind of big before they even begin to make you forget your tire is mounted on two solid walls (the clincher wall), versus just a round cross section of tubular laying nicely atop the entire cross section of a rim bed of approximately the same radius. Most clinchers, and even moreso tubeless clinchers, have a pretty stiff sidewall, although a noteable exception that I've experienced is the Specialized Turbo Cotton clincher. Very supple, but still a clincher. And if it's handling confidence in turns you want, well... you would be on tubulars from the get go.
And the "bounciness" I refer to does not come from a tire being too soft, on the contrary it comes from the tire being too full of air for it's size. The hysteresis effect if you will... where it starts bouncing off the objects it's trying to roll over, as opposed to just conforming to them and rolling over them nicely, without feeling vague. It's a balance of everything and very individual for sure. And for the most part I'm on pretty good pavement. I'm not on gravel, or cobbles, or anything else that might make me want for a bigger tire on my road bike. Perhaps if the road was fresh "unpacked" chipseal or just really coarse bad chipseal then yes, a bigger tire would be preferred in those instances at the appropriate lower pressure for the larger volume tire, but for the most part I consider the roads I ride to be fairly smooth, and thus the 25mm tubulars fit the bill nicely.
Again, here's a test which I encourage anyone to do if you have the wheels and tire choices. Find your most significant hill to climb, a mile or longer at 10% grade would for sure do nicely to demonstrate, but choose whatever you have at your disposal. Take your fattest tire and lower that pressure to the lowest you would ride for that tire. Now climb the hill. Next, do the same climb and use your low volume/higher pressure tire and ask yourself which one is easier to climb up that sucker with. I've done just that. I have my answer. I didn't like the vague feeling between tire and road of the larger tire compared to my 25mm benchmark. I don't really care what other people do, but that's how I feel. I gave away my Vlandererns to a friend. He says they're comfy. We are both happy.
For those old enough to remember... do you recall when mountain bikes really hit the cycling scene in a big way. Road bike sales dropped dramatically, because people were buying mountain bikes instead, whether or not they were used "in the mountains" or even off pavement. I bought one. But, if you recall, using those bikes had no hope of keeping up with the road bikes and their skinny tires, and the biggest change you could make to fix that, and many did, was to change those knobby tires to slicks and give them a little more air than they were really desinged for. I put slicks on. And if you wanted to take it a step further... people would even get skinnier rims and tires (almost roadish), and slap them on. Yup, did that too. More than anything that change helped level the differences. But after a while of that, it was clear that a proper road bike was the obvious better choice for the road, and many who bought their new "mountain" bikes but used them mostly on pavement, got proper road bikes. Got rid of my "mountain bike" and now have a nice stable of pure as snow road bikes, and I like it. I don't need another mountain bike. Unless I want to ride off road in the mountains, which I don't.
Last edited by Calnago on Sat Jun 22, 2019 10:33 pm, edited 1 time in total.
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fromtrektocolnago
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by fromtrektocolnago

i went to 32 mm and didn't like it for summer road cycling. so I would say it really depends on the application. The wider wheels are great for gravel and winter riding but for road cycling in the warmer months it feels more sluggist and feels like they are less agile. It may be a perception issue but that matters too
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spdntrxi
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by spdntrxi

been siting PRs on downhill segments.... uphill well no, but getting close to times set with same power and lighter bike/skinner tires though. My Cat6 current fitness level is not helping.

Imaking20
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by Imaking20

Calnago wrote:
Sat Jun 22, 2019 10:33 pm
. And for me, that means I like to feel the road...
This exact thought went through my mind several times today on my ride on Arenbergs. Love it.
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spdntrxi
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by spdntrxi

Imaking20 wrote:
Sun Jun 23, 2019 3:33 am
Calnago wrote:
Sat Jun 22, 2019 10:33 pm
. And for me, that means I like to feel the road...
This exact thought went through my mind several times today on my ride on Arenbergs. Love it.
with 28mm I can feel the road.. just less of what I dont want to feel :) so far no disconnect... proof is PR the downhills as of late

Methodical
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by Methodical

I just read through this thread and I think I will finally try the 28mm Continental 4kIIs on the Emonda and see what kind of ride quality I get or don't get. I've had these tires sitting around for many months doing nothing but collecting dust. I initially bought them for my '12 Madone; they fit but was too tight for comfort for me. I should have no fitment issue with the Emonda though. I'm in the Clydes category at 84kg and will start out with around 80psi. I don't race and have no desire to race; just group, crew and event rides.
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skyliner1004
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by skyliner1004

Wheres the limit to this? soon, we'll be at 45mm wide tires @ 30 psi! LOL!

Someone educatge me, i ride decently good roads, i weigh 160, Gp5000 25mm width, is 85/90 psi good for me? (for fastest speed, not comfort)
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guyc
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by guyc

Is 84kg a Clydesdale now?

yinzerniner
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by yinzerniner

skyliner1004 wrote:
Wed Aug 21, 2019 10:05 pm
Wheres the limit to this? soon, we'll be at 45mm wide tires @ 30 psi! LOL!

Someone educatge me, i ride decently good roads, i weigh 160, Gp5000 25mm width, is 85/90 psi good for me? (for fastest speed, not comfort)
As others have noted the "limit" really depends on priorities. For pure all-out speed you want the smallest frontal area possible that also matches tire/rim interface, but also provides enough comfort so your muscles aren't overly fatigued / jarred, has minimal rebound to limit vertical parasitic losses and still maintains minimal rolling resistance. If you can handle 23mm tires on 28mm wide and 80mm deep rims. pumped to 110psi without getting blown of the road or feeling like you've ridden over an endless armadillo more power to you!

With your weight 25mm at 85/90 seems like a good combo for fast speeds if you're on GP5K CL. If on the TL version maybe bump it down another 10-15psi or so. But no one can truly tell without some real-world testing.

by Weenie


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