23mm vs 25mm tyres

jkwilson84 · Post by **jkwilson84** » 15 Apr 2017 11:23

So I need to buy new tyres as mine are too worn, when shopping today found a lot of articles suggesting that a 25mm tyre is better than 23mm... now as a 110kg bloke I need all help I can get in equipment stakes so what would people suggest? 23mm or 25mm?

Dave Cox · Post by **Dave Cox** » 15 Apr 2017 12:24

23 is so last century now! I switched to 25mm a while ago and they are great but now people are using wider rims and going up to 28 even on fast bikes. I've got a 21mm front tyre somewhere if anyone wants it, Only problem with old frames is clearance particularly if you use mudguards.

Andy Terry · Post by **Andy Terry** » 15 Apr 2017 13:58

I switched from 23 to 25 last year and it really does make a difference. As Dave says, make sure the forks have enough clearance.

Philip Whiteman · Post by **Philip Whiteman** » 15 Apr 2017 16:41

25mm don't appear to wear quite so quickly*

*not subject to rigorous scientific enquiry

AlanW · Post by **AlanW** » 15 Apr 2017 20:29

Dave Cox · Post by **Dave Cox** » 15 Apr 2017 22:32

Just been reading the Aero edition of Cycling Weekly right tyres and wheels to get aero benefits apparently 23mm front and 25mm rear but I think you need to be tanking along before this works!

Rod Goodfellow · Post by **Rod Goodfellow** » 16 Apr 2017 12:00

Do you always believe Cycling Weekly (and the Daily Mail)?

laurence_cooley · Post by **laurence_cooley** » 16 Apr 2017 13:51

At the risk of attracting derision, I've never really been able to tell much difference.

jdtate101 · Post by **jdtate101** » 16 Apr 2017 18:49

Really depends on the rim width. I have a set of FFWD wheels that are quite wide and a 23mm comes up at 24.5mm. Generally I do races & TT's on 23's but do training and group rides on 25's. Winter rides are on 28's.

slogfester · Post by **slogfester** » 17 Apr 2017 08:03

yes, its the INNER wheel rim width which is important. No good trying to stuff a wide tyre in to a thin inner rim. I have 28 mm tyres (bontranger and GP4000s) on bontranger wheels with a 19.5 inner rim width and they handle on winding descents like nothing else I have ridden. I've smashed all my downhill times without even trying.

Matt Hale · Post by **Matt Hale** » 18 Apr 2017 12:53

Good article here:

https://intheknowcycling.com/2015/05/28 ... ike-tires/

...suggests trying to match your tyre width to your rim

petemarshall · Post by **petemarshall** » 19 Apr 2017 22:23

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

Yosser · Post by **Yosser** » 20 Apr 2017 12:25

I started racing again last year after a near 40 yr break. Tech had moved on massively so, having had a science based mentality all my life, I started with the research of all aspects of going faster. I am disappointed to find that my greatest advantage over the slightly less informed masses have been wiped out by the current vogue for fatter tyres. Get them. It was the single most advantageous tech investment I made. I would ride 28mm in a race situation if I had the frame clearance to suit. I ride 25 mm. There is almost no downside. Weight and slight aero penalty for the front tyre are the most prominent.

BTW the latest vogue is for the disc brake option, which will allow even wider tyres, combined with wide tubeless tyres.

Some people say that it is all marketing hype and that narrow tyres will be back ion no time. On the track tubs and v high pressures are the way. On the road, particularly rough surfaces, (are there any other sort now in Britain?) wide rule. Or you could emigrate to Mallorca with the super smooth tarmac. Just a thought.

slogfester · Post by **slogfester** » 17 May 2017 10:26

Just fitted 28 mm tyres to my Van Nicholas Yukon. Total no brainer for the roads here.

Tim · Post by **Tim** » 17 May 2017 12:37

23 all the way! cos of mudguard rub and because when I've ridden hire bikes with 25 I've not noticed as Laurence says and because in the lab tests the differences are so marginal and depends on brand and pressure and wheel it's not clear cut and because I rarely ride for over 2hours so comfort isnt top of considerations and because the move is driven by marketing and bike sales and because 23s are cheaper as no-one is buying them and because I've already got a spare pair of 23s!

Am considering going to 25s on summer racing bike now though as Dave seems to be getting on ok this year so we all need to copy him!

Yosser · Post by **Yosser** » 19 May 2017 11:38

Re Tyre science. The science is persuasive though it is important to remember that although science is the most measurable and so "provable" of life's imponderables it is also the most pragmatic in that it's main principle is any conclusions fit the current evidence only. In the future...

Given that, the measured facts are pretty conclusive. As Pete has already said, a good summary is given by GCN;

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

However note that not all the facts are fully explained. e.g. In contact patch discussion they should clearly point out that the difference in shape is crucial give that the pressure is the same for both tyre widths and so the contact area will be the same. (P=F/A gives A=F/P where F = wt of Bike + you). Plenty of people still believe narrow tyres have a smaller contact area than fat tyres per se.

Matt Hales post re matching the tyre width to the rim width is not to do with Rolling resistance (CRR) but to do with Aerodynamics where fat tyres DO loose out to Thinner tyres but this is outweighed (considerably?) by the CRR advantages according to the latest empirical evidence.
If you are up to the debate plenty of more exacting info out there.

JamesMartin001 · Post by **JamesMartin001** » 19 Oct 2024 12:54

Recent interview in the Guardian, and the ex pro mentioned 28mm at 70psi instead of 19mm at 120psi.

https://www.theguardian.com/sport/2023/ ... blown-away

I don't read up on the latest regarding tech. Personally use Schwalbe Marathon Plus 25-622, fed up with thorns on country rides causing so many **flat**s through thin tyres

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