I’m building a new road bike and can’t decide whether to go for 25mm or 28mm rubber. I’m not an athlete by any stretch of the imagination, weight around 88kg. Wheels are Fulcrum Racing Quattro Carbon Disc. Roads around here are pretty poor and mainly consist of chip seal.

There seems to be a lot of contradicatory articles, some stating 28mm as having lower rolling resistance. Has anyone upsized and noticed any pros or cons?

I’m on 30mm.

If you’re not racing, go wide! More grip, more comfortable, negligible speed difference.

I’m not sure if anyone has anaylsed the whole for slow fatties like us, but:

Wider means you can run lower pressure with less pinch flats. This means more comfort and grip.

Rolling resistance is less for a wider tyre at the same pressure.

Lower pressures increase rolling resistance less than previously thought.

Tiny increase in weight.

I run 28/25 on my fast bike, will be all 28 when the 25 dies.

I’d happily go 28mm if they’ll fit. If you’re not racing they’re a bit more comfortable, a bit more grippy and a bit more puncture resistant.

Even If you are racing, I’m not sure there’s evidence 28s are slower.

Or if you are racing still go wide. the Pro Peloton are mostly on 25’s and use 28’s on cobbles, so for a fatter recreational cyclist 28’s is not too great a leap. Though I couldn’t fit anything much bigger than 25’s in my road bike frame.

I went up in tyre width to 25’s from 23, but so far have not dropped my usual running pressure as i’m concerned about pinch flats on our UK potholed roads. The ride is definitely a bit more comfortable as the tyres are a bit larger in diameter, and the bike definitely feels a bit better and grippier in the bends. No downsides that I can detect, only upsides. I run 36c’s on my gravel/pub bike and they feel fine on the road, not draggy at all running 80 psi, not as ‘free rolling’ as the 23’s and 25’s I have run on my road bike, but not like running MTB tyres.

I’d give the 28’s a go.

28s on my winter bike, tubeless. I actually bought the frame because I had the tyres and they didn’t quite fit on the old frame.

Don’t seem any slower and I run them at about 70 psi. Certainly more comfort than 25s at 85 psi.

I put 28s on mine- it’s not actually a road bike, I don’t like drop bars so it’s officially a hybrid but it does the exact same job a road bike does. And no question for me that it’s better. Maybe on perfectly smooth roads at constant high speeds narrower works better but that’s not the world I ride in.

(I run slightly lower pressures so I’m not getting any rolling resistance benefit but I get a lot more control and imo that’s just enormously more important in normal use- it often adds up to more speed regardless.)

I get a lot more control and imo that’s just enormously more important in normal use- it often adds up to more speed regardless.)

Interesting point, and one I agree with. I’m sure that I’m faster with increased grip, not to mention the benefits of better braking. (Discs, obviously, but more grip = better braking.)

A while back Swiss Side and DT tested the effect of tyre size on rolling resistance and aerodynamics.

Thier conclusion (based on a 19mm internal width rim) was that if you’re average speech was over 35kmph the aero benefits of a 25c tyre made them faster but for slower riders the lower rolling resistance of a 28c made them more efficient. This was on all terrain, flat or hilly.

So racers or those who spend most of thier time belting along on chain gangs should be on 25s, everyone else will be faster on 28s.

Oh and tubeless road tyres roll faster and are more aerodynamic than tubs.

Speccing up a road bike for this summer and I’m going for 28c tubeless schwalbes.

My winter bike is on 25s that measure up as 28. Not slower and more grip. If you can go tubeless then the lower pressures are great.

Have been on 28s for a long time on my main bike. Have done thousands of miles, raced TTs etc.

If you’re racing, then maybe 25s, yeah…but I’ve not noticed any discernible disadvantage with 28s. And there are definitive advantages. For an everyday bike, I’d go 28s every time. So long as your bike will accommodate them.

Why stop at 28mm, unless it’s due to tyre clearance or very narrow rims?

I really wish I had tried wider 700/29er tyres earlier than I did in the last ~7 months on my FatNotFat 29er wheels, when I could have been using up to ~42mm tyres on my old Tricross Singlecross from 2010.

It’s not the 38c Marathon Cross than are limiting my speed while giving me the extra confidence of their bigger contact patch, it’s my fitness levels, which have dropped after almost two months without a decent ride until Thursday just gone. But even then, I was happy cruising at ~18mph on “Priory zprint” and apparently hit almost 26mph along “Riverside” Strava segments.

Apart from accelerating up to speed I find the 39mm on my ‘trendy touring bike’ way better than the 25s on my road bike. Comfier due to lower pressures, feel more stable on corners and crap road surfaces and I think the extra weight helps with stability when descending too.
I can’t get bigger than a 25 in the road bike but when I replace it I will make sure I get something with clearance for at least 28, preferably 30-32.

Different brands size up differently; something to be aware of. I use Conti GP4000s 23c that actually measure 25mm wide. Prefer these to wider tyres; they seem faster.

I’ve switched straight from 23s to 28 for my new winter bike. Love the comfort and surefootedness.

I moved from 23 to 25 on my bikes – I’d consider 28mm but to be honest, despite being on the heavy side, I’ve not encountered any issues with the 25’s.

rolling resistance of Xmm blah blah blah….

When there is bigger variation in RR between brands and models of the same* size tyre I think it’s silly to get hung up on the mm. Compare the tyres as a whole combination of size, weight, RR, carcass flexibility, puncture proofing, price, longevity etc.

Basically, get decent tyres appropriate to your use case and budget, if you have the choice between otherwise identical/similar options then I’d always go for the bigger ones bigger where possible unless that is at the detriment of quality if that makes sense?

ie: I’ll take a decent supple 23/25mm over a cheap and stiff 28mm, but I’d take a decent supple 30mm over those same 25s if available and it’ll fit.

Most of my road bikes are on 25 or 28s, one audax bike rolls on 32s, but one of them will only take 23s and it annoys the hell out of me, despite it being my ‘fast’ bike I’d put bigger on if I could, but as it is it gets the best 23s I can afford and consequently rides almost as comfy and grippy as the more mediocre bigger tyres.

A lot of it comes down to intended use though as well, we have a lot of crappy roads round here and bigger is nicer, I also tend to go for bigger for comfort reasons on longer audaxes as it makes a big difference over the long rides, for an hour or two you can put up with being rattled around on skinny tyres, but 8+ hours of that gets tedious, fatigues you and slows you down in the long run.

* Not to mention that brand X’s 25mm can easily be the same size as brand Y’s 28 (or 23!)

My opinion:

1. To my mind it’s primarily about the road surface. The closer you are to polished marble, the better off you are with harder, narrower tyres. And the closer you are to rubble, the better of you are with softer, fatter ones. Which means on most British roads, narrow tyres can certainly be disadvantageous.

2. It’s also about rim width, or it is if you’re like me and can’t abide wallowy tyres. I wouldn’t stick even a 28 on my Excellights because they’d be vague in corners unless I whacked up the pressure enough to make them a harder ride than 23s, but I’m happy with a 37 on my rather wider Infernos.

3. It’s also a psychological thing. To me a narrow tyre often still *feels* faster even it isn’t. And when I *feel* faster I give it more beans, so I *am* faster. Where the goal is endurance rather than speed this still has an effect: feeling more efficient keeps me more upbeat.

4. It’s also down to the tyre carcass. There’s no point replacing a supple narrow tyre with a marginally wider wooden one.

Long story short, if you’re torn between 25 and 28 in the same tyre, personally I’d go 28 unless you have very narrow rims or are buying very cheap tyres.

YMMV on all fronts.

For the 2014 Paris Roubaix, Niki Terpstra used a 28mm tyre front and 30mm tyre rear for a winning time of 6 hours 9 minutes over a distance of 256 kilometres.
As long as you dont try to pump them up until they are about to burst they roll OK.
60psi is a good starting point.

1. Why “The closer you are to polished marble, the better off you are with harder, narrower tyres”?

2. What pressure are you running? Im often at 70-80 and never felt any problem on old fashioned narrow rims and wider tyres.

My new bike has 28s on. Can’t make a totally honest assessment as I’ve gone from 25mm tyres on an alloy, rim braked bike to 28mm tyres on a steel disc braked bike, but I’ve certainly not seen a downside.

I’m 83ish kg, don’t race, the bike was intended to be built for comfort rather than speed, and it delivers, partly the frame, partly the tyres. Grip is better in corners, braking is amazing, as you’d expect with wider tyres and discs. My rides have been maybe 1mph slower average since I got this bike, but the bike is 2lbs heavier than the old bike, I’m 4-5lbs heavier since I last rode the old bike, and it’s winter, so I’m not blaming the tyres.

1. Because you don’t want any deformation on a smooth surface, since there are no irregularities which would otherwise drain energy, so you may as well go narrower and lighter.

2. Never made an accurate measurement, it’s all a matter of balancing the various criteria until it feels right. I’m 14 stone, though, which might be a factor.

I think one of the issues here is that most people, and this certainly includes myself, won’t have been able to test this in a truly scientific way. But at the same time, although I’m a great believer in testing things in a scientific way, I’ve still never found that the “fatter is better now” science plays out quite as effectively for me as the lab would suggest, because I think the psychological effects kick in. I still feel like narrower tyres seem faster, until I hit really crappy roads. And to an extent feeling faster makes me faster, and feeling more efficient makes me feel less fatigued.

The “YMMV” is strong in this one 🙂

I swapped from some decent Michelins in 25mm to some Challenge Strada Biancas in 30mm. Didn’t find any problems or down sides and they did ride nicely. I have always ridden tyres harder than many, probably as I didn’t swap from tubs until about 6 years ago, so my 25s were run at 100psi. The Stradas were run at 80psi. As a wide tyre is more comfortable than a thin one at the same pressure I split the difference. Wide tyres but hard.
You could feel the difference the is resistance with the Stradas at minimum pressure, 50psi and maximum pressure, 80psi.
I now run 30mm tubeless S ones at 65/70 psi. Fine.
Unless every gram is important I would be riding the widest tyre I could fit nowadays.

@bez, I get YMMV but…

1 the wider tyre still has lower RR for the same pressure, do I don’t see/get your point.
2 not sure what you’re trying to say, folk must either corner way harder than me or run daft low pressures to have squirming issues with wider tyre on narrow rims.

Is there a point where a tyre becomes unnecessarily wide?

For example I am a light rider (about 55 KGs), and my bike is a steel Charge Plug 3, which weighs about 12 KGs with guards etc. I am still running the fairly poor 28 mm Kenda Kwik Tendrils tyres it came with. I’m looking at changing them for something better and am torn between 28mm Duranos and either 32 m or 35 mm Hyper Voyagers.

I don’t race, just use the bike for solo leisure rides and the occasional 35 mile round trip commute on poor roads and cycle paths/gravel tracks. The 28’s have coped with this so far, but would someone with my combined bike/rider weight benefit from going as wide as 35mm? Or would 28 or 32 be a better choice? Most of the arguments seem to be for overweight non racy types, I’m just skinny and unfit!

I’m on 35mm. Not noticeably slower than when I had 28mm. I’m not fit mind.

1 the wider tyre still has lower RR for the same pressure, do I don’t see/get your point.

I don’t even know what rolling resistance means, but I don’t think it needs a genius to work out that a narrower tyre is going to be fast than a wider tyre on a smooth bit of tarmac.

I put 28mm on my road bike for some bike packing and haven’t taken them off. Really comfy and fast and means I can sometimes take a cheeky bridleway. Might go 30mm next…

I use 30mm schwable s-one on the winter bike & currently have 25mm Victoria pave on the summer bike. If I could fit 30mm’s on the summer bike, I’d do that too.

Personally I find there is very little speed differential between the two but the comfort of the 30mm’s over the 25mm’s is substantially better

My road bike has very limited clearance, i’m not even 100% sure a 25c will fit.
When it’s new bike time however there will be no hesitation going to 28’s and it will be a requirement when buying.

[video]https://www.youtube.com/watch?v=yrHxQg1OW0A[/video]

I don’t think it needs a genius to work out that a narrower tyre is going to be fast than a wider tyre on a smooth bit of tarmac.

It’s not taken any geniuses to work out that’s incorrect

David. The point is that much modern research indicates that a wider tyre is faster. Not sure I understand that but I reckon that its sure enough to be true.
Of course all of this is subject to too many variations to give a 100% perfectly definitive answer.
Of course everything has to be relative. My 42 mm road tyres which are used for 95% gravel are noticeably slower than the 32 mm CX tyres or my 30 mm Stradas on the same tracks. They weigh a ton mind.

1. A wider tyre will also be harder at a given pressure. The polished marble thing is a red herring to be honest: if you want zero delection you just get a tyre to maximum pressure and you’re done. I’m the real world we’re primarily talking about minimising energy losses over various surfaces, which is all about matching the suspension, ie the tyre, to the irregularities of those surfaces. Running a wider tyre at the same pressure you’d use for a smaller one doesn’t make any sense on non-smooth surfaces.

2. Like I said, YMMV, but I’ve found I don’t get on with narrow rims and wider tyres, and that applies both on and off road. If it works for you, great, roll with it.

1. Your red herring!…
2. What effects do you complain of?

I have 28mm Schwalbe The One run tubeless on my road bike which are a vast improvement on even the 25mms on my old bike. I would definitely go bigger but thats the limit for my forks unfortunately.

33mm file-tread here, perfect for devon “roads”

I’ve been running nothing but 35s for the past 2 years.

Some comparisons

http://www.conti-tyres.co.uk/download_files/Wide_Tyre_Test_TourMagazine_2014_UK.pdf