41ants

It's a steel frame roadie that isn't the lightest in the world, so, No, I am not trying to compete. I do it for the enjoyment and its one of the few things that I have found that keeps by body fat percentage under 10% by riding a few days a week and still allowing me to consume 4,000+ calories/day. Win Win for me.

Rowan

One of the things that people forget in these discussions is tyre pressure, especially when we are talking about the type of riding the OP mentions, and not racing.

I've been through the 32, 28, 25 and 23 scenarios. I currently run 23s on the CF single at 90-95psi, well under the maximum recommended pressure and they are comfortable for the distances I do, and certainly not discernibly slower.

I've run 25s and 28s at max or higher pressures, and my butt has taking a beating each time. We run 28s on the tandem, and again they are around 95psi; I inflated them to 105psi for a century a while ago and boy, was that a mistake.

Playing with tyre pressures, for me, is an important starting point. Not enough people do it, in my opinion.

achoo

Wrong:

https://www.rouesartisanales.com/article-1503651.html

Well, well, what do you know. The lowest measured rolling resistance comes from the FATTER tires.

The link even takes the trouble to explain WHY.

achoo

Why wouldn't you run the fatter tires at lower pressure? (Excepting the tandem...)

Rowan

If you read it again, you will see I said the fatter tyres at max (or higher pressure). The extra bit about the higher pressure was back in the day when everyone was saying "pump it hard, you'll go faster", even for fatter tyres. But the maximum pressure was still pretty darned hard.

The tandem tyres are run at pressures below the maximum recommended on the sidewall.

Bob Dopolina 

Funny.

I was in the same room, looking at the same machine, talking to the same guys at Continental in Korbach Germany who had actually run those tests when I worked with Continental.

Their conclusions were a bit different. Since we're talking about clinchers let's focus on those:

1. Look at the puncture resistance of those 'faster' rolling tires. Pretty low, huh? I guess it's because they don't have a breaker belt. This means better casing deflection which yields lower rolling resistance.

2. What's the faster tire with a breaker? 23mm.

3. Look at the point about tire pressure. Tufu, with a stiff casing, roll better at higher pressure. Tires like Deda see a performance decrease at higher pressure.

4. Last point, these tests are from 2005 and published 2006 (IIRC). Tire compounds and breaker material have all taken a huge leap since then rendering this data useless.

Based on these test Continental decided to focus on 23mm tires for road as they offered the best, all round performance in terms of speed, aero and comfort.

Big guys should still be on 25's for the extra comfort and to reduce pinch flats.

Northwestrider

He was saying, hmm don't really want your business it seems to me. Go elsewhere

dahut

And with an arse as big as mine, 28's still seem a little small.....

jamesdak 

Actually I think they go hand and hand. Running the larger 25c tire lets me run less pressure than with 23c while not increasing the risk of a pinch flat. There is where the true comfort factor comes in from.

Bob Dopolina 

It's always a mixed calculation of speed, comfort and puncture resistance.

Pick the tire and pressure that best applies to your needs and you're good to go.

dahut

That, and the fact that 28's are all that will fit in my roadies frame.

Rowan

Well, true to a degree, but Bob's post also identifies that pressures can influence how a tyre can feel and sometimes it's counter-intuitive.

The point for me is that with the 23C tyres we (I and Machka) use, we inflate to (slightly) lower pressures than maximum for comfort, and that a variation of just 5 to 10 psi can make a difference in feel through the seat as well as handling when it comes to corners and road camber (squirrelly compared with direct compared with kludgy). Experimenting with an accurate gauge helps determine which suits us.

Bear in mind we are not short-distance racers, but do a lot of long-distance riding where comfort becomes paramount and indeed does affect overall speed. And I am in this discussion because it's the Road forum where not everyone races.

achoo

My post was a refutation of a more-than-somewhat risible claim that narrow tires are always faster on bicycles based on a photo of what appeared to be a bunch of Soapbox Derby race cars.

rangerdavid

yet another reason to buy in the internet and avoid the $6.00 per hour college student working at the lbs who thinks he knows more than you do. Plus on line is cheaper, more than likely.

rangerdavid

What the hell is a ARSE?? Do you mean ASS????

dahut

The polite version. Force of habit - sorry.

Rowan

Don't be put off, dahut. We'll get these know-all Americans to understand real English before we are finished!

matroskin

How fast do you usually go? Extra resistance will matter more if you go 40mph compared to 20 mph.

And by the way go back to that LBS and tell the guy what your friends at your LBF think about him

ancker

Race cars would gladly use very thing tires if they could. The wide tires are there for increased grip (something you need with 700+HP and cornering at 200mph), not because aerodynamics are moot.

Certainly narrower tires have more potential to go faster. Less frontal air resistance is a good thing. Whether or not they actually ARE faster probably has to do with more than whether one is 2mm wider than the other.

rangerdavid

I'm sorry. I did not intend to offend by my post.

dahut

Wait 'til I call something 'bollocks.' Or the 'dogs danglies.'
It'll be on then.

Rowan

Have a look at the tyres on cars built specifically for speed trials on salt flats around the world. Plus the front wheels on drag cars. Very thin.

The width of tyres in Indy/Champcars and F1 is regulated, I think, and yes, the width has much to do with grip on corners. Back in the day, it was not unusual for race cars to put on thinner treaded tyres when the tracks got wet. And the front wheels on the race cars are smaller because the rules prevent the aero bodywork from covering them. Does anyone remember the Tyrell six-wheel F1 car that had really small front tyres/wheels?

If everyone was racing, then the 2mm difference in width on a bicycle tyre might make a difference. But because the tyre is leading edge, some of the aero difference would depend on what is coming behind, too... as in the rim and its configuration.

Also don't forget that because this is the Road forum, there are people who are running 38mm tyres, and that 15mm difference could arguably be seen to make a tyre less aerodynamically efficient. But ultimately, the rider on a 38mm tyres likely couldn't care less about it.

Bob Dopolina 

My understanding of your post is that you were suggesting 25c tires are faster than 23c tires and provided a link to prove it.

My point is that it's not that simple and if you further examine the data from the link you posted at least that much is apparent.

mustang1

I moved from 23 to 25 earlier this year and noticed a difference in speed. But hang in there while I explain the whole lot....

Cycling for about 5-10 minutes, I notice the 23 is faster than 25. but since my typical ride is 45 minutes long, I cant sustain the kind of speed (due to my lack of fitness) where I would appreciate a 23 being faster than a 25. So for me, for rides under 10 mins (probably more like 5 mins), 23 is faster. For my normal rides, 23 and 25 are the same.

Which do I prefer? 25
Why? Ride comfort is a touch better (I use 120psi in both 23 and 25 tires but I guess extra air volume makes the ride a little better even at same psi?)
Flats? IDK if it's my imagination, but I seem to flat less on 25 (I weigh 200lbs)
Installation? 25 is a touch easier to install

I also rode the 25s at reduced psi (100 front, 105 rear). The ride was softer, but not smoother. Didn't have the sharpness. So I'm back to 120psi, the way I like it.

OP: try 25, I think you will like it. I dont think I'd get a 28 even if my frame could fit it, because it's too far removed from 'a racing application'... and although i'm too fat to race, I want my tires to be race-like damn it!

EDIT: my other bike has 32mm tires. OMG the ride quality is soooo comfortable. But I never 'gun' my fat ass for the traffic lights when I'm using that bike.

RJM

Just remember, we are talking about a distance of this: --

Big deal.

I love my 32s