Is 23 faster than 25mm tyres

lismore7

Cycled last year on GP 4000 23mm tyres but changed to Conti 4 Season 25s this winter, for better grip in the wet & cold.
The 25s seem to be slower, either that or I enjoyed Xmas more than I thought.

Like to hear the views of others who have moved from 23 to 25mm or 25 back to 23mm?

Lumen

I went 23->25->28->23-21.

I don't know which is objectively faster, but IMO 23mm feels nicest on half-decent roads. Anything more than 23mm feels a bit dead to me.

On crap chip-and-seal roads I'd take 28s.

Alek

I went 23>25>28>35 and can definitely tell the difference in comfort, while minimal to none in speed. I don't race on the road though

But hey, maybe I just got better :eek::pac:

rtmie

No personal view to offer but this and this suggest 25 faster than 23

Alek

The 25s seem to be slower, either that or I enjoyed Xmas more than I thought.

Btw, do you use the same pressure? Make it bit lower and see how it goes. (i.e. from 100/80 to 90/70 rear/front for 80kg rider+bike).

68 lost souls

Alek wrote: »

Btw, do you use the same pressure? Make it bit lower and see how it goes. (i.e. from 100/80 to 90/70 rear/front for 80kg rider+bike).

Is that what most people use? I run 110 on both front and rear.

nak

lismore7 wrote: »

Cycled last year on GP 4000 23mm tyres but changed to Conti 4 Season 25s this winter, for better grip in the wet & cold.
The 25s seem to be slower, either that or I enjoyed Xmas more than I thought.

Like to hear the views of others who have moved from 23 to 25mm or 25 back to 23mm?

Maybe the difference in tread pattern?

Alek

Is that what most people use? I run 110 on both front and rear.

Most people should run pressure calculated for their weight and tyre width

I use the 15% drop calculator (attached)

cdaly_

Apparently wider is faster but the variation between brand/tyre model matters a lot more than tyre width.

lismore7

I don't race, just social.
I'm no expert but the 25s do feel slower than the 23s.
Where I notice it mostly is on decents, which I've done on both sizes.

However, yes.. I have dropped the pressure from 100 (summer) down to 85/90 winter and the make of tyre is different from Conti GP 4000s over to Conti 4 Seasons. Would the above make a difference to speed rather than tyre size?

Alek

but the variation between brand/tyre model matters a lot more than tyre width.

Interesting.

I have received 38mm Vittoria Hypers today, reputably faster than 35mm Kojaks - according to Schwalbe own tests, rolling resistance of the former is 20W, the latter 29W. But: the first thing I've noticed was that sidewalls on Vittorias are quite a bit stiffer than on Kojaks.

Where the reduced resistance may be coming from then? Can the casing be supplier on the road but quite opposite in hand? Robber compound? (I doubt so). TPI of the casing?

uphillonly

nak wrote: »

Maybe the difference in tread pattern?

As per rtmie's link, pros seem to have moved to 25.

Possibly down to tyre build & weight.
GP 4 season 25mm - 230g
4000 23Mm - 205g.

4000s are designed for racing & 4 seasons for durability. So providing it's not snake oil marketing the 4000s should be faster on good roads.

They do a 25mm 4000 if you want to test on behalf of the Boards community.

OldBean

I've always found this quite interesting:

https://janheine.wordpress.com/2014/01/01/tires-how-wide-is-too-wide/

He's written a few other entries on tyre sizing, rolling resistance and comfort.

I've used 23mm, 25mm, 32mm and finally finding at 28mm to be great.

lismore7

uphillonly wrote: »

As per rtmie's link, pros seem to have moved to 25.

Possibly down to tyre build & weight.
GP 4 season 25mm - 230g
4000 23Mm - 205g.

4000s are designed for racing & 4 seasons for durability. So providing it's not snake oil marketing the 4000s should be faster on good roads.

They do a 25mm 4000 if you want to test on behalf of the Boards community.

Might wait till it gets a tad warmer and drier, before I become the Boards tyre tester :eek:

rtmie

Devil is in the detail wrt tyre pressure it would seem from reading. From link above

"you probably noticed that I've been referring to 25mm benefits with the clause, "at the same pressure," throughout this piece. This is important, because most users have the tendency to drop pressure on these tires. The reason for this is an increase in comfort, but this comfort slightly impacts the benefits of lowered rolling resistance. With a 25mm tire, you can replicate a 23mm pressure feel at a significantly lower pressure, which effectively removes much of the sour notes from the tarmac. At this lower pressure, however, you're accepting a heavier tire while denying yourself much of its benefits” outside of comfort that is"

cdaly_

Alek wrote: »

Interesting.

I have received 38mm Vittoria Hypers today, reputably faster than 35mm Kojaks - according to Schwalbe own tests, rolling resistance of the former is 20W, the latter 29W.

I'm currently testing 35mm Hypers. Swapped out new Schwalbe Marathon Supremes. Haven't run a full week on them yet but they feel nice. I'll put the Schwalbes back on in a while and see how they feel. Maybe after the Angel of Mons in a fortnight...

Lumen

rtmie wrote: »

you probably noticed that I've been referring to 25mm benefits with the clause, "at the same pressure" throughout this piece. This is important, because most users have the tendency to drop pressure on these tires

Indeed. GP 4000s II @ 28mm has a max inflation pressure of 116psi but recommend 95psi, and since I only run 23mm tyres at 100psi I'd continue to use that pressure for 28s.

http://www.conti-tyres.co.uk/conticycle/ti_GP4000SII.shtml

Ultremo ZX HS 380 goes up to 115psi but I wouldn't trust my life to an Ultremo anywhere near max pressure.

http://www.schwalbetires.com/bike_tires/racing_tires/ultremo_zx

uphillonly

OldBean wrote: »

I've always found this quite interesting:

https://janheine.wordpress.com/2014/01/01/tires-how-wide-is-too-wide/

He's written a few other entries on tyre sizing, rolling resistance and comfort.

I've used 23mm, 25mm, 32mm and finally finding at 28mm to be great.

Thanks, interesting read. Now I might become a Boards tester for GP4000 at 25mm.

ford2600

On even a sportive/endurance bike you do well to fit wider than 25mm.
With 25mm only some brands(and also rim width dependent) will allow full crud type mudguards. Durano plus in 25 are wider than gp4 season for example.

I don't notice any speed penalty having gone from 23-28 and back to 25(in order to fit mudguards)

AstraMonti

I think tyre and tube quality is more important than width when speed is concern. I would much prefer a good quality 25mm than a cheap 23mm. Between two equal tyres I still think 25 is faster on Irish roads.

lismore7

I think that's a fair point.....having lower tyre pressure and using a winter type tyre, means a little speed will be sacrificed for better grip.

Having read all the above, I might get a set of GP 4000s in 25mm for the summer.
So despite moving up to 25s, the fact that I'd be using a racing tyre and at a higher pressure, should resume my normal speeds and with the added bonus of a little extra grip and a slightly less bumpy ride on the crap roads round my area?

theautophile

There is another factor that seems to be being over-looked - rim width. The latest generations of wider rims are clouding this 23 V's 25 issue. The rim manufacturers are stating that the wider rims change the profile of the tyres and that in most cases a 23C tyre will increase it's profile width to nearly that of a 25C tyre on a thinner rim. As a complete system (tyre and wide rim) the manufacturers recommend 23's as being the more aero package and that you can also run lower pressures!

I've been running 23's on both 24 and 25mm wide (at the brake track) rims for the last year and have to say I've been surprised by the comfort and speed. Using the same tyres on an older set of thinner rimmed wheels the ride has been quite different (same pressures), slightly harsher and more juddery at the limit.

Don't have a link for it, but Paul Lew at Reynolds has a great tech section/blog explaining this in far greater detail and some interesting things to say about 'Open tubular' designs too, relating to the importance of internal rim width, well worth a read!

I'm going to experiment with 25's over the next couple of months just to see if they are in fact faster for me on wider rims or if simply the pro's ride them for comfort and greater grip.

CramCycle

I run GP4000S 25mm between 100 and 120psi. Firstly they are bigger than some other brands 25mm at 120psi, looking closer to a 28mm than a 25mm.

Feels faster than the 23mm but not by much. To be fair since I rarely push myself over and above my limits, it could be more due to increased wheel diameter.

In my opinion on Irish roads, it will always be harder to tell which is faster as our poor surface quality in alot of the country saps so much energy anyway.

Basically, I would recommend moving to France to become faster rather than change your tyres :pac:

Unknown Soldier

theautophile wrote: »

There is another factor that seems to be being over-looked - rim width. The latest generations of wider rims are clouding this 23 V's 25 issue. The rim manufacturers are stating that the wider rims change the profile of the tyres and that in most cases a 23C tyre will increase it's profile width to nearly that of a 25C tyre on a thinner rim. As a complete system (tyre and wide rim) the manufacturers recommend 23's as being the more aero package and that you can also run lower pressures!
<snip>

Very true. If you read any of the reviews for the Canyon Endurace they think that the 25mm contis on the DT Swiss R23 spline (rims have an internal width of 18mm rather than 15mm) add a lot to the comfort.
Quote from Road.cc

"The smartest move by Canyon has been to fit DT Swiss R23 Spline wheels with a wide profile rim and 25mm Continental Grand Prix 4000S II tyres. The Spline rims measure 18mm internally and 23mm externally. The impact this has on the tyres is to balloon them out to 27mm."

The fastest tyre I have had are the stock Mavic 23mm ones that came with the wheels. The are specific to front and rear but they aren't really designed for our roads. Super fast though!

I went with a 23mm front/25mm rear last year using Conti 4000s but have decided to go 25mm/25mm this year after discovering at the end of last year that I actually own a full on racing bike and I don't race but do semi-endurance from time to time. I've always ran my tyres at 120 psi fwiw.

I think the following pic explains the 23 v 25 theory very well, leaving aside all the various other factors such as make/material etc. (A 25mm Marathon plus is a tractor tyre!) Sorry if i'm repeating a pic that is in one of the links above. It's a side view of a tyre.

Beasty

Unknown Soldier wrote: »

I think the following pic explains the 23 v 25 theory very well, leaving aside all the various other factors such as make/material etc. (A 25mm Marathon plus is a tractor tyre!) Sorry if i'm repeating a pic that is in one of the links above. It's a side view of a tyre.

That's assuming the same pressure. Generally you can counter it by having higher pressure in narrower tyres. Putting aside comfort and the effect of road quality, there's a reason trackies tend to use narrower tyres (often 19mm) that can be run at very high pressures (tubs) - they certainly not considered slower than wider tyres

ROK ON

AstraMonti wrote: »

I think tyre and tube quality is more important than width when speed is concern. I would much prefer a good quality 25mm than a cheap 23mm. Between two equal tyres I still think 25 is faster on Irish roads.

This.

Some tyres roll faster than others - at least it seems that way to me.
Like a broken record in this one, but I love the feel and look of Vittoria Open Pave. To me they seem to be faster than the other tyres that I use.

Seweryn

I was going to put 25mm tyres onto my new bike that (after idling for two years, haha) I managed to screw together using my decommissioned wheels with (worn out) 23mm tyres.
Looking at the rather not generous clearance, would you say that the bike would take anything larger than worn 23mm? I know, the only way is to try out, but I have no spare 25mm tyre anywhere.

ford2600

Seweryn wrote: »

I was going to put 25mm tyres onto my new bike that (after idling for two years, haha) I managed to screw together using my decommissioned wheels with (worn out) 23mm tyres.
Looking at the rather not generous clearance, would you say that the bike would take anything larger than worn 23mm? I know, the only way is to try out, but I have no spare 25mm tyre anywhere.

If your not in a hurry you can try two gp4season 25mm

Seweryn

ford2600 wrote: »

If your not in a hurry you can try two gp4season 25mm

Not in a hurry .

Lumen

ROK ON wrote: »

This.

Some tyres roll faster than others - at least it seems that way to me.
Like a broken record in this one, but I love the feel and look of Vittoria Open Pave. To me they seem to be faster than the other tyres that I use.

Vittoria test slower than Conti from what I've read in Tour magazine and elsewhere.

e.g.
http://www.conti-tyres.co.uk/conticycle/download_files/TyreTests/RoadBike_winter_test_02_11.pdf



...although here it comes out well.

http://www.biketechreview.com/tires_old/images/AFM_tire_testing_rev9.pdf

Idleater

Lumen wrote: »

Vittoria test slower than Conti from what I've read in Tour magazine and elsewhere.

e.g.
http://www.conti-tyres.co.uk/conticycle/download_files/TyreTests/RoadBike_winter_test_02_11.pdf

Presumably that graph can be read differently if you state it as grip at 30 kmph. I wouldn't class 4 seasons and open pave as remotely close in terms of suppleness and feel. The tradeoff is higher power loss, though arguably more power directed in the correct or intended direction.

Lumen

Idleater wrote: »

Presumably that graph can be read differently if you state it as grip at 30 kmph. I wouldn't class 4 seasons and open pave as remotely close in terms of suppleness and feel. The tradeoff is higher power loss, though arguably more power directed in the correct or intended direction.

I don't think grip and rolling resistance are necessarily correlated.

Contis always seem to come out near best in both.

In any case, anyone obsessed with rolling resistance should presumably be running latex tubes.