How did we delude ourselves about 23mm?

[Racingt]

For decades, we believed that thin 23mm high pressure, 120psi tyres were the way to be fast. Now it appears we were wrong, and 30mm tyres at 85psi are faster.
Is it true or just the industries way of getting us to buy new bikes?

[reohn2]

It's true on rougher roads(point me to anything else in the UK),if the road is billiard table smooth,HP,quality rubber beats anything.
The problem is there isn't much of that kind of road anywhere to be found in these isles
Chip n seal rules and so HP 23mm tyre bounce a lot whereas bigger similarly specced tyre absorbe the uneven surface and ride more comfortably,just as fast and grip better,especially on fast descents,but they need to be ridden at much lower pressures.
That's the overall story,of course it ain't that simple but there anomalies and differences but it's near enough,I'll wait for the nay sayers.

[Brucey]

I'd agree with that. Near to me there is a nice smooth run and 23s are still faster than anything else on that. On the other roads locally, not so much....

There are other factors, including that...

- they have learned to make wider (say 25mm) rims and tyres that are quite aero, so you are not paying a huge aero penalty for having slightly wider tyres
- the move to disc brakes has (by and large) made forks a lot stiffer than they could be (in any given material); arguably you are more likely to need wider tyres to be remotely comfy if you have disc brakes fitted.
- the cycling public (who bought 'proper road bikes') used to be almost exclusively skinny folk who raced, or ex-racers who knew to be careful. These days the average is at least 10-15kg heavier, they are likely to be less skilled, and are on worse roads; these people need fatter tyres and/or to be more careful than one could perhaps be reasonably expected to be.
- modern rims are (for several reasons) more likely to be catastrophically damaged by a pothole
- pro cycling is a shop window for what punters buy, so if 'the industry' wants/needs to shift road bikes with fatter tyres, they will put their development efforts in that area, persuade the pros to use similar kit and they will use it provided it doesn't slow them down unduly.

If you want to know what is 'fastest' of all then look at what is used on the track in pursuit events, or in time trials (by time-trial specialists; in a typical long stage race less than 10% of the riders are really flat out in a TT stage and/or have any expectation of winning; their equipment choices often reflect that).

cheers

[Mick F]

I'll wait for the nay sayers.

Here I am!

I'm more than happy with my 23mm Vittoria Rubino Pro Slicks.
I was happy with the 20mm versions but I suffered from pinch punctures once or twice as they were a bit narrow for the rims. 23mm are perfect and when they wear out, I'll be buying more.

It's all to do with the bike IMHO, not the width of the tyre per se. I have a nice and light and springy old fashioned 531c Mercian frame of course, and I do not suffer with bounce and roughness. I can compare the ride with a nice and supple suspended Moulton, and although the Moulton absorbs rough bumps and ruts better, the ride isn't much different on normal roads.

There are roads that I prefer Moulton over Mercian, but these are more of the narrow tiny steep rural bumpy badly surfaced variety of roads.
No issues whatsoever with 23mm tyres on Mercian. It's a "road bike" and is ridden on roads.

[ianrobo]

23's suit me fine and with no issues on a 400km ride ....

There is a lot of bull about this of course and you just ride with what makes you comfortable ...

[Mick F]

23's suit me fine and with no issues on a 400km ride ....

There is a lot of bull about this of course and you just ride with what makes you comfortable ...

Spot on.

[The utility cyclist]

For decades, we believed that thin 23mm high pressure, 120psi tyres were the way to be fast. Now it appears we were wrong, and 30mm tyres at 85psi are faster.
Is it true or just the industries way of getting us to buy new bikes?

It's a load of cobblers because the wider tyres are only better in the rolling resistance dept IF they are blown up to the same pressure as their narrower counterpart, which they aren't going to be in real world use, and then you get to the elephant in the room ... aero, wider is less aero and consumes more power to push through the air.

You only need look at the bicycle rolling resistance web page and you'll see that the fastest tyres are also the narrowest 23mm tyres, though on modern wider rims (a 17mm in the test rim on BRR) they come up to about 25mm. This is tested on a rough rolling drum, so sadly the wider tyre is faster nonsense is just that.

That said, ride whatever one wants to ride, I don't care, but when the proof of wider tyres being faster is absolute tosh and only in an extreme scenario which virtually no-one would do then I call BS.

[nigelnightmare]

Actually it's the LOWER pressure that helps to smooth out the ride giving lower rolling resistance by allowing the tyre to deflect, thereby preventing the bike from bouncing over the SMALL "imperfections" in the road.

AERO! Just how fast do you think you need to be moving for it to make any difference in the real world.

At least that's the theory.

[iandriver]

I wouldn't be surprised if the move by the pros to wider tyres is mainly down to super stiff frames and super stiff deep section Carbon rims. Something has to give. As for the rest of us, just get out there and ride....

[pwa]

I agree that a lower pressure than the max stated on the side of the tyre allows a smoother, less juddery and more efficient ride. So faster over average road surfaces. But wider tyres don't make me faster. A 25mm pair of tyres at less than 100psi carries me faster and easier than 35mm tyres. And I don't think that is just my imagination. Where the wider tyres score is in the way I can just ride over substantial holes in the road surface instead of steering around them. I suppose that makes the journey shorter!

[foxyrider]

Who''s deluded?

Doesn't seem to matter which bike I ride, if I fit narrower tyres I go faster. 23's - for me at least give the balance of comfort and performance that I like.

If you don't like 23's don't use them but please don't go labelling everyone who does as misguided idiots.

At the end of the day bike companies want to sell new bikes so if that means putting on un needed 'tech' or telling everyone they've been wrong for the last century they will. Seems to catch enough sheep with cash to spare everytime.

[The utility cyclist]

Actually it's the LOWER pressure that helps to smooth out the ride giving lower rolling resistance by allowing the tyre to deflect, thereby preventing the bike from bouncing over the SMALL "imperfections" in the road.

AERO! Just how fast do you think you need to be moving for it to make any difference in the real world.

At least that's the theory.

And as I said, on a ROUGH rolling road and a constantly rough surface at that, the narrower tyre wins out at pressures that are what one would use, only IF the wider tyres are at unfeasibly higher pressures does that rolling resistance just beat the narrower tyre on a rough road. Anytime you are on a reasonably smooth surface and you're losing out loads.
If you want to pump a 28mm tyre up to 120psi knock yourself out

[RickH]

I know some folk like to dismiss Jan Heine but his tests are explained and it would be easy to repeat them & show the errors in them or disprove them. So far I've not found anyone who has!

His latest blog suggests some of the problems of measuring rolling resistance tests using round rolling surfaces as a possible bias towards higher pressures that doesn't translate into the real world (unless you do most of your riding on a planet with a diameter of a few feet or less ).

I used to ride 23mm tyres. In 2008 with a new bike I was running 25mm Gatorskins & then switched to 28mm Grand Prix 4 seasons which were noticeably more comfortable but not measurably slower.

For the last year or so I've been riding a heavier bike with 23mm rims (internal) & 38 mm Vittoria Voyager Hypers (running at 40mm actual width). I may have lost a little absolute speed (but haven't really tested it - the only time I took a detour to one of the fastest local descents I had a headwind) but my average speed doesn't seem to be affected much, if at all. The fact that I can ride over ~1" stones or lumps & barely notice it means I can just keep going.

Last August Bank Holiday I did the Wild Wales Challenge on the new bike - 90.8 miles, 8885 ft ascent logged (Strava link). I didn't really have enough miles in my legs beforehand but, apart from tired legs, I felt better than I had on a long ride for a good long while. Some of the road surfacing, particularly near Abergele, seemed to have been contracted out to a company more used to patchwork quilting than road maintenance. But me & the bike took it all in our stride. There was only one time when the surface on a sharp bend on a particularly steep downhill caused me to have to change my intended line through the corner. I overheard some other riders on narrow tyred lighter machines discussing the "squeaky bum" moments they had had a little while later.

Round these parts the billiard table smooth road surfaces are notable by their rarity!

[Raleigh Steve]

For decades, we believed that thin 23mm high pressure, 120psi tyres were the way to be fast. Now it appears we were wrong, and 30mm tyres at 85psi are faster.
Is it true or just the industries way of getting us to buy new bikes?

It's a load of cobblers because the wider tyres are only better in the rolling resistance dept IF they are blown up to the same pressure as their narrower counterpart, which they aren't going to be in real world use, and then you get to the elephant in the room ... aero, wider is less aero and consumes more power to push through the air.


You only need look at the bicycle rolling resistance web page and you'll see that the fastest tyres are also the narrowest 23mm tyres, though on modern wider rims (a 17mm in the test rim on BRR) they come up to about 25mm. This is tested on a rough rolling drum, so sadly the wider tyre is faster nonsense is just that.

That said, ride whatever one wants to ride, I don't care, but when the proof of wider tyres being faster is absolute tosh and only in an extreme scenario which virtually no-one would do then I call BS.

I think the argument against this is that the steel drum tests ignore the rider, who absorbs energy being jiggled. If a fat tyre means the rider is jiggled less then more of the rider’s power goes to moving the bike forward and less to heating up the rider.

Steve

[peetee]

A lot of it is down to the frame.
My Reynolds 708 machine is on 25mm, the 753 with similar geometry is on 23mm but has a more forgiving ride.