Anyone gone large (28mm tyres)

[Fab Foodie]

I've gone to 28mm and like the results in terms of comfort and roadholding, with no impact on speed. However, I've done so on modern rims, which are a bit wider than the old standard, and give a good profile to the tyre. I'd stick to 25mm on older, narrower rims where a 28 would end up with a lightbulb profile.

Agree it's a downside on narrow rims. I run my 28c on 23mm rims and the profile is peachy. I once put 28c on old narrow rims and they were a bit squirmy.

 

[SpokeyDokey]

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?

Put as wide as you can on if you have clearance and the rim can take them.

Some of us have been riding with 28/32/35 for some time and a chubbier tyre (esp' 32/35) is way more comfortable than a 23 or even 25. Any 23/25 I have ever ridden has a bone jarring ride unless you are lucky enough to be able to always ride on super-smooth asphalt.

Up until early last year (?) or thereabouts the world was pro-skinny and everyone on chubby rubber was off base but now we are told that wider equals less rolling resistance (albeit they are generally heavier) the cycling fraternity is taking heed with its usual Lemming-like zeal and going wide.

I think some of the Pro's in the Paris-Roubaix were running 30mm last time around too.

 

[Bonno]

Back in the day it was assumed that narrower was faster, hence Smokin Joe ending up with a pair of 18mm on his race bike. A few of his fillings had their lives shortened that season, where he also learned that 18mm tyres and greasy roads were not happy bedfellows.

Ha...I was of the same mindset back in the day, running 18mm's tyres and they of course had to be pumped up to at least 120psi !!
Learnt my lesson when i found a small patch of diesel at a bus stop and ended up with broken collarbone and stitches to head wound
Changed back to massive 23mm's after that!

Some 30 years later i'm running 32's on my Racelight T... with psi down to about 80

 

[mjr]

No reason to stop at 32mm. My commuter has Schwalbe 35mm tyres which are supposed to measure 37mm in real life and find these ideal for all and any trip's. Potholes are a mere inconvenience as I can crash through anything without fear, apart from being thrown from the bike or breaking the frame.....

My worst ever crash-where-I-sort-of-stayed-on-the-bike was blundering through a potcrater and being bruised on the backs of the thighs by the saddle as I rejoined the bike. That was on 28mm front, 35mm rear. Not even a pinch-flat from that.

My current tyre width of choice for day-to-day riding is 37mm where they fit

 

[Saluki]

Hubs has 28mm tyres on his Whyte and that is his 'go to' bike in most circumstances. The carbon roadie gets left on the rack and he takes that Whyte flipping everywhere. He says that the tyres are more comfy.

 

[andyoxon]

28mm currently on my steel bike (previously 32mm), and 23 + guards on other bike (preferred to 25mm without guards). I have been experimenting with reducing tyre pressures and go for approx, 28mm: 75F/90R, 23mm: 85F:95R; for me this seems enough for good comfort & keeping potential pinch flats at bay.

 

[e-rider]

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?

the evidence does indeed contradict itself - how can you have larger tyres that deform less under the same pressure hence leading to no increase in rolling resistance but at the same time provide a more comfortable ride?
The fact is larger tyres can be used at 'slightly' reduced pressures with no increased risk of pinch flats and also provide a slightly smoother ride - but lower the pressure will increase rolling resistance slightly and the larger tyre will be heavier, also slowing you down somewhat.
Pump a 25 or 28 up to 120psi and the evidence suggests no loss of speed as less tyre deformaton balances the small weight gain - however I can't see how you will gain comfort in the situation, perhaps just slightly more grip

 

[Dogtrousers]

Just out of interest, are these changes to "rolling resistance" something that one might actually notice, or is it akin to the difference between riding with water in your bottle vs riding with much denser and heavier orange squash.

In short - are you all talking cobblers or is this something that might actually make sense?

 

[Ajax Bay]

are these changes to "rolling resistance" something that one might actually notice

I think that this in the region of 'marginal gains'. In the lab it amounts to (very roughly) an extra watt for each tyre for each 10psi less. But on the road this might or might not cancel out because the rider's body doesn't shake about so much (using and losing energy). And lower pressures equal a more comfortable ride. I've read elsewhere that carrying an extra 1kg over 'normal' terrain requires an additional 0.4w. So getting the tyre type, width and pressure 'right' could save a rider the same as losing 10kg of weight/baggage. Would you "actually notice" if you were carrying 10kg on the back, other than an alteration in bike handling? Recycling a post on another thread below.

This article is worth a read: I recommend it to you. The main argument is that by running wider tyres at lower pressures you reduce the suspension losses in the rider/bike combo and thus real rolling resistance is reduced. On a smooth drum (ie the rollingresistance.com tests) rollingresistance reduces very slightly as the pressure on the same tyre is increased - but this higher pressure results in more, for want of a better word, 'bouncing' on rough surfaces (eg roads) which actually means a narrower tyre at higher pressure (to avoid pinch flats) is 'slower'.

At higher speeds (eg 45+kph) aero aspects may come into play, and wider tyres tend to be heavier (which may be an issue if lots of acceleration involved - as opposed to steady riding). It would be good if tyre manufacturers of the good road tyres (Michelin, Continental, Vittoria, Schwalbe et al) made 28s which measured 28 and 32s in the same 'road tyre' range, as opposed to the step across (ie not up) to the fastest but heavier 'touring' tyres eg M Supremes. And frames were designed to cope with 32s, without getting too 'heavy' and 'gravel'.

 

[smutchin]

the fastest but heavier 'touring' tyres eg M Supremes

Worth noting that Marathon Supremes in 32c are lighter than Duranos in 25c, and IME faster - Duranos are so stiff that you lose loads of speed on rough roads simply because you're juddering so badly - a good example of the 'suspension losses' you mention. Obviously there are much more supple options in 25mm that would be a lot more comfortable and have less rolling resistance than the Duranos.

The disc-brake version of the new Trek Domane comes with 32mm tyres as standard and that's definitely a dedicated road bike, not an 'adventure' or 'gravel' bike. Shame the non-disc version can only take 28mm tyres, but the limitation there is the brake callipers - you need brakes with a longer drop to fit larger tyres (especially if you want space for mudguards as well). But I think bike frame design is moving in the right direction in this regard - my Felt Z35 that I bought 8 years ago was sold as an 'endurance' bike but can only just fit 25mm tyres. That would be enough to put me right off the bike if I was in the market again now.

 

[Ajax Bay]

Worth noting that Marathon Supremes in 32c are lighter than Duranos in 25c, and IME faster

Not quite sure on that (the weight). In the http://www.bicyclerollingresistance.com/ tests the Duranos in 25 are shown as 240g and the Marathon Supremes in 37 are 440g. I'd be surprised if the latter were less than 350g in the 32mm version.
Nevertheless, according to the tests (see below) at, say 80psi, the Marathon Supremes in 37 do roll better than Duranos in 25, and that's in a lab! So much better when the rubber hits the tarmac. I still think there'd be a good market for the three road tyres (comparison below) if they made them in 32, for the increasing number of riders with frames that offer the clearances.
Compare/continental-grand-prix-4-season-2015-vs-michelin-pro-4-service-course-2014-vs-schwalbe-durano-2015
Compare/continental-sport-contact-2016-vs-schwalbe-marathon-supreme-2016-vs-vittoria-voyager-hyper-2016

 

[dim]

just to sidetrack and confirm ....

there's not much difference between 25mm tyres and 28mm tyres?

reason that I'm asking is because I'm on the market for another bike that I will use for commuting in winter as well as some solo Audax rides ... and with some of the bikes that I'm looking at, I doubt that 28's will fit, but 25's will be fine (no chance of 32's fitting)

 

[smutchin]

Not quite sure on that (the weight). In the http://www.bicyclerollingresistance.com/ tests the Duranos in 25 are shown as 240g and the Marathon Supremes in 37 are 440g. I'd be surprised if the latter were less than 350g in the 32mm version.

I weighed them myself on my kitchen scales! I don't recall the precise numbers but the Duranos were definitely heavier.

It was a while ago, admittedly, so there may be some detail I've forgotten that explains the discrepancy.

ETA: just had a look at the Schwalbe site - they list Supremes in 32c at 380g, and Durano Plus in 25c at... 380g! So maybe it was the Durano Plus I had, though I could have sworn it was standard Duranos.

 

[Ajax Bay]

there's not much difference between 25mm tyres and 28mm tyres?
. . . reason that I'm asking is because I'm on the market for another bike that I will use for commuting in winter as well as some solo Audax rides

Apart from the facile 3mm answer (NB tyre width quoted v actual has some variation qv but see rollingresistance.com for their tests) the difference is that you'll be able to run them about 15psi less. So more comfortable and minimal difference in rolling resistance. You'll see some very proficient audaxers on wider tyres (eg 32) eg the bloke who got round Mille Pennines (1005km) in about 61 hours (00:57 in video actually 40-622 measuring 38mm) - he's the one with grey hair in an 'upright' stance (link).

https://www.cyclechat.net/threads/n...-my-rights-to-return-them.202764/post-4334295
Extract (edited): Spurred on by @I like Skol's thought that " I don't think road bike sized tyres really stretch much between 60-120Psi."
I decided to test this by measuring the width of the new Continental GP 4 Seasons 28-622 I'd just mounted on 622-15 Mavic MA3 rims (NB 15mm inside bead, butyl inner) at pressures from 70psi to 110psi (max rating is 115psi).
psi width (mm)
70 25.6
80 25.8
90 25.95
100 26.1
110 26.2

Note that @andrew_s 's measurement on 13mm rims @ 100psi was 25.7mm.

 

[dim]

Apart from the facile 3mm answer (NB tyre width quoted v actual has some variation qv but see rollingresistance.com for their tests) the difference is that you'll be able to run them about 15psi less. So more comfortable and minimal difference in rolling resistance. You'll see some very proficient audaxers on wider tyres (eg 32) eg the bloke who got round Mille Pennines (1005km) in about 61 hours (00:57 in video actually 40-622 measuring 38mm) - he's the one with grey hair in an 'upright' stance (link).

https://www.cyclechat.net/threads/n...-my-rights-to-return-them.202764/post-4334295
Extract (edited): Spurred on by @I like Skol's thought that " I don't think road bike sized tyres really stretch much between 60-120Psi."
I decided to test this by measuring the width of the new Continental GP 4 Seasons 28-622 I'd just mounted on 622-15 Mavic MA3 rims (NB 15mm inside bead, butyl inner) at pressures from 70psi to 110psi (max rating is 115psi).
psi width (mm)
70 25.6
80 25.8
90 25.95
100 26.1
110 26.2

Note that @andrew_s 's measurement on 13mm rims @ 100psi was 25.7mm.

thanks for that .... I have bookmarked your post and will closer look tomorow