32mm vs 25mm tyre on cyclocross bike for road use?

[Mattievrs]

Recently bought a cyclocross bike for use over winter on the roads. It came with 35mm rapid rob nobbly tyres which I have swapped out for some 32mm Vittoria Randonneur tyres. They feel ok but I’m wondering for road use if 25mm tyres would be better in terms of rolling resistance? Any one shed some light or experience on what would be the best for road use?

Thanks

[meic]

There is great disagreement about that on this forum.

My experience is that the right 25/28mm will be faster than the 32/35/37mm options.

You can take different road surfaces and say bigger tyres will be faster on a rough road surface and thinner tyres faster on a totally smooth road surface. Where you road surface lies on that spectrum could make the difference.

I reckon that you should try out the two options yourself and add to the overall disagreement with your own first hand experience.

[Samuel D]

When it comes to rolling resistance, the way the tyre is constructed matters a great deal more than the width. However, Vittoria Randonneur tyres have high rolling resistance, so almost any 25 mm tyre would roll more easily. See Bicycle Rolling Resistance for more info.

The Vittoria Voyager Hyper would have something like half the rolling resistance despite being of similar width.

[Spinners]

The rim width will have a bearing on ride quality too. If your bike was running 35mm tyres then there's a fair chance that a 25m tyre will be a bit stretched across the rim width and not as plump as a 25mm on, say, an Open Pro sized rim.

Over the past few weeks I've been riding bikes with 25mm, 30mm and 35mm tyres and rate them in that order on speed and in reverse order on comfort.

[iandriver]

The Randonneur Pro are a much better tyre, the carcass is totally different to the non pro version (120tpi vs 60tpi). They come in chronically under size in my experience. The 32mm version is more like a 28mm and suits my cross bike very nicely. A 32mm or 35mm Voyager Hyper also works very nicely on a cross bike. These come up full size and still allow a good degree bridle way bashing in the dryer weather.

[gbnz]

. They come in chronically under size in my experience. The 32mm version is more like a 28mm .

I'd agree, I received a 32mm Vittoria Randonneur last week and had forgotten that it's equivalent to a Michelin/Schwalbe 28mm tyre in respect to width (I hadn't used the Randonneur for several years, but was able to make a direct comparison with the above makes).

In terms of speed, I'd always said that a 25/28mm tyre was faster than a 32/35mm tyre, refusing to accept this nonsense that a wider tyre could be quicker (Nb. I even used to 20mm tyes on the road bike due to this reason). Until 2014 when I was doing a 26 mile commute as a matter of routine, 3-4 times a week over the same route and was annoyed that the wider rim I'd fitted required me to fit a wider tyre (I "knew" it'd be heavier and slower).

In fact my average speed showed an immediate and sustained increase in speed over many months

[Mattievrs]

Hmmm, plenty to think about here! I have a set of unused 25mm Randonneur in the shed from a previous project that never happen so I think I’ll mount a tyre to see how it fits first. If it looks ok and not too stretched then I’ll do them both and test them out.

Either way I’ll report back ASAP.

[John_S]

Hi Mattievrs,

My apologies because I'm not technical at all but you've already been getting lots of good advice and info on this subject and I'm sure you'll get loads of replies giving you plenty of info & advice on this subject.

However I saw a video on pretty much this subject and although it's not a direct test of the same bike using lots of different types of tyres towards the end of the video they do test on the road the same bike on two different sets of tyres:-

https://youtu.be/Kr7u9hgUKJs

Also my apologies because this is perhaps even more off topic but I think that there is a connection. I say that because the type of bike &/or tyres that work the best will depend upon the surface on which you're riding. Now I'll hold my hands up and say that the cobblestones of Paris-Roubaixare not really representative at all of anything that any of us are likely to be riding. However it's a good extreme example of the difference that different types of bikes & the tyres that are on them make to speed (if that's what the concern is).

https://youtu.be/QvO74sZxVs4

I'm sure that there are so many different permutations of road surfaces, tyre sizes, compounds and tread that make this a difficult subject to analyse but I hope that you find the right tyre for your intended use.

John

[landsurfer]

I ride every where on 28mm Marathons on my road bike, up hill, down dale, on road, off road, forest and mountain tracks ..... tried 23, 25 and 32 mm tyres and came back to 28mm Marathons as the best of the bunch.

[PH]

Load and pressure will have a major effect on the way a tyre behaves. There seems little point to me considering width without the others. It’s no surprise people come to different conclusions when they do.

[landsurfer]

Well ... I'm 6' 3", 110kg and ride a SPA Steel Touring ... everywhere ...
Yes, its all about loading.
Some 70kg wippet would probably find my set up very uncomfortable as the issue with suspension, even if just by tyre size, is the ability to actually compress it.

[Samuel D]

The Randonneur Pro are a much better tyre, the carcass is totally different to the non pro version (120tpi vs 60tpi).

It’s worse still: the non-Pro has a 30 TPI casing.

I have a set of unused 25mm Randonneur in the shed from a previous project that never happen so I think I’ll mount a tyre to see how it fits first.

That’s the same, slow tyre you’re using now, just in a narrower section. It may feel different (less comfortable), but it won’t be much faster. For easier rolling, you need a faster tyre. Comparable tyres vary by about a factor of two in rolling resistance.

[RickH]

I used to ride on 25/28mm tyres (about 5 years on 25mm Gatorskins followed by about 3 on 28mm Conti Grand Prix 4 Seasons) The 28s were definitely noticably more comfortable to ride & didn't appear to be any slower. They were on a Kinesis Tk so 28 was the biggest that fit. Earlier this year I got a Kona Sutra which I have been running with 38mm Vittoria Voyager Hypers from new. I don't think I've ridden the Kinesis since getting the Kona (maybe time for an N-1! ).

The Kona is probably a couple of kg heavier than the Kinesis but doesn't seem to be any slower on the Hypers - apart from, possibly, at the very top end downhill speed but I've not really taken the bike on any routes that I know I have previously got significantly above 40mph when the conditions are favourable (still not quite managed to break the 50mph barrier in the UK!). Now I like to know where and how far I've been & my rides have been uploaded to Strava back to mid 2014 (mostly privately) but I don't "do" segments. Even on regular routes I've little idea of where they are & don't consciously take any notice of them. What I do note that after the event I'm regularly setting personal bests even though I'm pretty sure I'm not quite as fit as I was a couple of years ago. What I do notice is that I don't have to weave around the pockmarked, badly repaired sections of road like I would on 25/28mm tyres & when I get on unmade stuff things feel much less sketchy - there's one unmade, gravelly bit of road just down from us that I am happy to ride down a good 5+mph faster on the Hypers than I used to on narrower tyres, the handling feels much more like my old mountainbike on that surface.

[MikeF]

Load and pressure will have a major effect on the way a tyre behaves. There seems little point to me considering width without the others. It’s no surprise people come to different conclusions when they do.

Indeed, but tyre construction and tread also make a big difference. Hypers have quite a low rolling resistance at low pressures where other tyres would have noticeable drag. I gain the impression that the 35mm have a lower rolling resistance than 32mm ones, but it's just my impression.

[RickH]

Load and pressure will have a major effect on the way a tyre behaves. There seems little point to me considering width without the others. It’s no surprise people come to different conclusions when they do.

Indeed, but tyre construction and tread also make a big difference. Hypers have quite a low rolling resistance at low pressures where other tyres would have noticeable drag. I gain the impression that the 35mm have a lower rolling resistance than 32mm ones, but it's just my impression.

I forgot to mention that I'm running the Hypers at 30psi Front & 35psi rear (with maybe an extra 5psi if the bike is loaded up) & I'm currently nearly 80kg.