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Not so Fast– 700x25c NOT Faster than 23s afterall...

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Not so Fast– 700x25c NOT Faster than 23s afterall...

Old 04-29-18, 12:21 AM
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Not so Fast– 700x25c NOT Faster than 23s afterall...

25s are more comfortable but they're not faster. The comfort/performance tradeoff makes sense but thinking it's all a freebie apparently is nothing but wishful thinking (or, should we say... marketing). I'm riding rims that are 22 wide by 24 high and the bike came with 25s. Based on what you read I can enjoy greater comfort riding on these larger 25c tires, even at a lower psi, than going to 23s. The real story is, even at the same psi, I'd be faster with 23s. I am happy to sacrifice that little bit of extra performance for a more comfortable ride but facts are facts-- just like I can't put on 28s and go faster yet.

Here's the skinny: https://intheknowcycling.com/2016/04...s-wheel-sizes/
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Old 04-29-18, 12:56 AM
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This (from the article above)--

To the first question, I almost invariably answer that you don’t want anything wider than a 23C tire if you want to maximize speed. If, however, you put comfort ahead of speed, go ahead with the 25C tire.

There are no wheels that I’m aware of where mounting 25C tires on the rims will make you faster or equally fast compared to that of narrower sized tires of the same model on the same rims.
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Old 04-29-18, 03:48 AM
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Wider tires are a comfort thing only. I've never believed they ride faster, despite what all the 'experts' on forums like these have convinced themselves of.
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Old 04-29-18, 08:42 AM
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Anything over 25 feels like crap on a road bike, just saying. This fad about wide tires on race bikes is silly, if you want a cruiser, get a cruiser.
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Old 04-29-18, 09:59 AM
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True, true, for more comfort but probably also the convenience of fewer flats riding at lower pressure; and, a fad for sure but alsoa great marketing angle, enticing road bike aficionados to consider buying into the latest technology because their current bike has become way passé. It also provides a good excuse too, to sell 23s that are more like 25s and, 25s that are more like 27s after being mounted on your pre ~2015 rims.
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Old 04-29-18, 10:13 AM
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Ugh intheknowcycling is such a terrible site. Don't read that site it's awful. There's no coherent argument and it ends up just being a information overload in an attempt to sway the reader. Like everything else posted over there.
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Old 04-29-18, 10:21 AM
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Yes, yes! Choose discomfort in exchange for saving about a minute over the length of a century. I reckon there is an inverse proportion of people worried about saving 5 seconds on a 40k, and people who are fast enough in a 40k to actually worry about the 5 seconds.

My favorite part is where they tried to prove their assertion about 23C tires by taking numbers from the very Bicyclerolligresistance.com test that showed that the Conti GP4000 700x28 was the fastest of the Conti GP4000 23-25-28 tires tested.

"The bigger the tire, the lower the rolling resistance at the same air pressure. When you run lower air pressures, the differences get even bigger. At a comfortable 80 psi, you're only giving up 2-3 watts for a pair of tires when going for the 28C size. That's good to know when you decide to go for a bigger tire because you like a more comfortable ride or ride on bad roads with potholes a lot. All in all, I think the differences aren't that significant, in particular between the 23C and 25C tires."
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Old 04-29-18, 10:44 AM
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Originally Posted by DrIsotope View Post
Yes, yes! Choose discomfort in exchange for saving about a minute over the length of a century.
Of course the increase in comfort would be less fatiguing to the rider, so you could actually finish stronger/faster.
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Old 04-29-18, 10:50 AM
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Originally Posted by FrenchFit View Post
Anything over 25 feels like crap on a road bike, just saying. This fad about wide tires on race bikes is silly, if you want a cruiser, get a cruiser.
I'll mention that this fad isn't especially new. People were riding road bikes with Del Mondo tubular tires 50 years ago. (I never heard a number for the width for those or any other of the tubulars of those days but I can assure you Del Mondos were a big, fat tire.)

Ben
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Old 04-29-18, 10:57 AM
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Originally Posted by noodle soup View Post
Of course the increase in comfort would be less fatiguing to the rider, so you could actually finish stronger/faster.
This has been my experience on the less-than-pristine roads around here.
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Old 04-29-18, 11:07 AM
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Originally Posted by DrIsotope View Post
...



My favorite part is where they tried to prove their assertion about 23C tires by taking numbers from the very Bicyclerolli...


.
True and one takeaway, I do appreciate the good fortune -- unplanned on my part when I purchased -- to have a bike that'd migrated to the new rim-width standard to accommodate bigger tires, in as much as fatter tires on the old style (pre-2015) 17mm narrow rims are less efficient than if they're mounted on--e.g., 19s (from the Bicyclerollingresistance article reviewing Conti 4000s)

A 28C [which is pretty much a 25 that actually measures 27] tire on a rim that is designed for a 23C tire will perform poorer.
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Old 04-29-18, 11:10 AM
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Whoa, whoa. We can't have unreasonable discussions about drum-measured rolling resistance if we start taking the comfort of the rider into consideration! We should all be cramming in 130psi and just suffering for the sake of almighty speed!

And by "perform poorer" he was talking about something on the order of 2 watts. Four watts for the pair. Meanwhile, the tire I see out on the roads/trails most often is the Conti Gatorskin, which is a penalty of a whole lot more than 2 watts.
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Old 04-29-18, 11:40 AM
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Originally Posted by 79pmooney View Post
I'll mention that this fad isn't especially new. People were riding road bikes with Del Mondo tubular tires 50 years ago. (I never heard a number for the width for those or any other of the tubulars of those days but I can assure you Del Mondos were a big, fat tire.)

Ben
I've read estimates anywhere between 25mm and 30mm. Jan Heine measured the set they used in the BQ tire tests at 28mm. Based on some descriptions, I wish I could go back in time and try them for myself, but there are a lot of good tires available now, too.
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Old 04-29-18, 11:43 AM
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I never experience discomfort on my 20c tires - and I ride a lot.
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Old 04-29-18, 11:46 AM
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Originally Posted by Spoonrobot View Post
Ugh intheknowcycling is such a terrible site. Don't read that site it's awful. There's no coherent argument and it ends up just being a information overload in an attempt to sway the reader. Like everything else posted over there.
That was my impression too. Massive information overload leading up to a conclusion that was personal opinion anyway.
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Old 04-29-18, 12:16 PM
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Originally Posted by exmechanic89 View Post
I never experience discomfort on my 20c tires - and I ride a lot.
A few years ago I did a triathlon where the back half of the bike course was so rough with chipseal and cracks that I was literally worried about bolts backing out and the bike falling apart under me. That was on Conti Attack 22s; I certainly would have been faster on 25s at lower pressure, giving up a couple of watts on the front half but being able to go a couple mph faster on the back half because of not being bounced around like riding on a paint mixer.

The Attacks were wonderfully quick and plenty comfortable on the smooth tarmac portion. I wonder if you'd love your 20s so much if you were riding on Texas farm roads.
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Old 04-29-18, 12:23 PM
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Originally Posted by Bah Humbug View Post
I wonder if you'd love your 20s so much if you were riding on Texas farm roads.
Feel free to 'wonder' all you like.
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Old 04-29-18, 12:29 PM
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Originally Posted by exmechanic89 View Post
Feel free to 'wonder' all you like.
I mean, if you tell me you're comfortable with your bike vibrating like the bed in an hourly motel, well I can't tell you you're wrong. A lot of people would rather do something to prevent that though.
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Old 04-29-18, 12:34 PM
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Originally Posted by 79pmooney View Post
I'll mention that this fad isn't especially new. People were riding road bikes with Del Mondo tubular tires 50 years ago. (I never heard a number for the width for those or any other of the tubulars of those days but I can assure you Del Mondos were a big, fat tire.)

Ben
Clément Campionato del Mondo tubulars were 28mm.
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Old 04-29-18, 12:48 PM
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Originally Posted by Bah Humbug View Post
I mean, if you tell me you're comfortable with your bike vibrating like the bed in an hourly motel, well I can't tell you you're wrong. A lot of people would rather do something to prevent that though.
If you say so.
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Old 04-29-18, 02:08 PM
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Originally Posted by McBTC View Post
25s are more comfortable but they're not faster. The comfort/performance tradeoff makes sense but thinking it's all a freebie apparently is nothing but wishful thinking (or, should we say... marketing). I'm riding rims that are 22 wide by 24 high and the bike came with 25s. Based on what you read I can enjoy greater comfort riding on these larger 25c tires, even at a lower psi, than going to 23s. The real story is, even at the same psi, I'd be faster with 23s. I am happy to sacrifice that little bit of extra performance for a more comfortable ride but facts are facts-- just like I can't put on 28s and go faster yet.

Here's the skinny: https://intheknowcycling.com/2016/04...s-wheel-sizes/
Well, if there is an article on the internet about it then it must be true.
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Old 04-29-18, 02:59 PM
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One of the arguments for wider tires I've seen is that rolling resistance on an essentially-flat surface is different from the real-life case. While higher pressures measure better on a flat surface, real-life bouncing about amounts to energy loss. (The main assumption in the argument is that wider tires allow you to safely use lower pressures.)
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Old 04-29-18, 03:00 PM
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Originally Posted by McBTC View Post
Seeing this "Improved 1) rolling resistance, or the reduction in friction between the tire and the road, ..." proves the author doesn't know (or doesn't care) what he's talking about. Rolling resistance derives from the energy loss due to hysteresis in tire deformation and recovery (with some important geometric terms) and has nothing to do with friction.
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Old 04-29-18, 03:32 PM
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I still run Conti GP 4000 II 23 but now use about less air pressure. I suppose 108 and 98 on back and front. I don't buy the wider tire business unless you are on gravel or really bad chip seal. I try to pick decent roads but things happen. Mine a plenty comfortable but I say some due to titanium frame.
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Old 04-29-18, 04:02 PM
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I moved up to 25's 8-10 years when everyone else did. Now I'm back to 23's. They're just make the bike feel a hair more agile and the difference in "comfort" is negligible. Two millimeters is two millimeters. Not exactly a night and day difference.
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