23MM AND 25MM tyres........any significant difference ?
I have a set of 25mm Bontrager tyres on my Trek 1000 racing bike. When I was last in bike shop, I was checking out 23mm Continental Gator skin tyres. Does the 2mm smaller tyre yield anything significant when compared to the 25mm, or would it take a 21mm tyre to make a change worth my while ? My average is currently 18.5mph - 19 mph .
What are your thoughts ?
Jimmy
What are your thoughts ?
Jimmy
0
Comments
-
I wish my average speed was as high as yours. :oops:JimmyK wrote:What are your thoughts ?0 -
About 2mm.
No, I don't think you'll notice a significant difference - the 23s will be a little less comfy, and you can pump them up harder so they'll roll faster (note that at the same pressure wider tyres are actually faster), but most of the difference you'll feel will be the "new kit" effect. Don't bother changing unless you need new tyres.0 -
I pump my 25mm tyres to 100 psi and use 18-25mm tubes, what pressure can you inflate 23 mm tyre to without worrying about a blowout at speed or endless run of punctures ?
Jimmy0 -
Depends on the tyre. I think my 23C Krylons state 116psi on the sidewalls while Vredestein Fortezza Tricomps say they're good for up to12 bar (170psi). In the case of the Vredestein's the limiting factor may well be the tube or the rim itself rather than the tyre.
To date I've not felt the need to go over 125psi on any of my 23c tyres be it a Mondo Pro, GP4000, GP4000S or Fortezza Tricomp.0 -
I prefer the feel of 23mm, 25mm feels too cushy. Apperently, 23mm is the best width to go with, any smaller and it becomes more square cornered, so turns less comfortably, any wider and it increases rolling resistance.
But this is just a general view,I'm sure the actual difference in rolling resistance is minimal and the cornering affect might not be that great.
I'd say give 23mm a try. I prefer it.0 -
whats a good tyre pressure for 23s and safe ?
Jimmy0 -
Less than most people seem to think. It does of course depend on your weight. At ~70kg I never pump my 23s up to more than 100psi (too high a pressure actually results in more rolling resistance unless you're riding on really smooth roads).JimmyK wrote:whats a good tyre pressure for 23s and safe ?0 -
I've got Vredestein Fortezza Tricomps which seem to like a little more pressure compared to others as they are quite supple and feel a little soft at lower pressures, so Ive got 130 in front and 140-150 in back (they are rated to 175). I'm close to 112kg though so need a bit more pressure than most and I like a less spongy ride.0
-
I am with aracer on this. unless you're going to be on really smooth roads or the track then high pressures are not the way to go, especially if you're riding in the mountains.
I weigh 73kg and go for about 105 rear and 100 front on 23mm tyres.
i find the ride more comfortable with pressures even lower than that but am paranoid i'm trading off speed.0 -
-
All things being equal - tyre construction, pressure and road surface, a wider tyre will always have a lower rolling resistance than a narrower tyre. The rolling resistance graphs confrim this. a shorther wider contact patch is prodcued which reduces the flex in the tyre carcass.
The only reason that racing bikes have traditionally favoured narrower tyres is because there is a persistent myth that 'narrower is better' and the obsession with low rotational weight (as narrower tyres are marginally lighter)
Notice the trend in racing bike since the 1970's - 18mm used to be standard, then 20mm becoame the norm and now 23mm is standard fitment. I predict that 25mm will become more common - remember that a 25mm tyre is not just 8% wider but contains about 25% more air than a 23mm tyre
Gradually cyclists are learning that wider tyres offer lower rolling resistance, improved comfort and often forgotten - better road holding and are more sure footed on descents.
As for pressure - modern clinchers can sustain almost any pressure you can get your track pump up to - though i wouldn;'t bother going above 110-120 psi on normal roads as beyond this is counter productive.
For every type of surface there is an optimum pressure - and it does depend on the suppleness of the tyre - the more supple the higher the pressure you cna get away with, but as a general guide
ultra snmotth surfaces like a track or smooth concrete- 130-150psi
Normal tarmac - around 90-110psi
Rough tarmac/ city roads - 70-80psi
Daniel0 -
JimmyK wrote:I have a set of 25mm Bontrager tyres on my Trek 1000 racing bike. When I was last in bike shop, I was checking out 23mm Continental Gator skin tyres. Does the 2mm smaller tyre yield anything significant when compared to the 25mm, or would it take a 21mm tyre to make a change worth my while ? My average is currently 18.5mph - 19 mph .
You'll notice a big difference - if you don't reset your computer
"Like a pig towing a cart-load of sausages - I draw my own conclusions"0 -
I weight 14 stone and prefer 25mm Conti's for commuting - I also have some 25mm Vittoria Corsa CX wire on's on my VITUS - they are comfier than 23mm tyres and less harsh, certainly dont feel any slower though. My two racing bikes have 23mm tyres. I suspect that when these wear out I will replace with 25mm's - its only recently that they have been commonly available. Ultimately its down to personal preference - as I get older I find the comfort of a slightly wider tyre more appealing0
-
the 23s on less than perfect roads are bum thumpers then ?
Jimmy0 -
@ Pinerellofan - good post...
boonen mentions using a lower pressure here:
http://www.specialized.com/bc/SBCWhatsN ... efp=USHome0 -
I'm over 80kgs and I tend to go for between 100 and 120psi - used to use 120 routinely but go more for 110-115 in the dry now. I wouldn't want to go much below 100 - certainly not down to 70-80 on a 23mm tyre.
it's a hard life if you don't weaken.0 -
JimmyK wrote:the 23s on less than perfect roads are bum thumpers then ?
Jimmy
No, not really. Both my wife and I are using 23mm Schwalbe Blizzards running at 90/100 psi front/rear on bumpy Derbyshire lanes; I find them perfectly acceptable and she hasn't complained either.
GeoffOld cyclists never die; they just fit smaller chainrings ... and pedal faster0 -
Doesn't aerodynamics come into it too? If your tyre is a different width to your rim (fatter or thinner), you are affecting the drag. Don't know how significant this is though.
It sees 23mm tyres are about the same width as the rims. The 25mm's I have on my commuter are a bit wider.
Oh, and for the 'poll' aspect of this thread, I weigh 10 stone, and run about 100psi in my fast bike tyres (23mm Pro Race 2's), and about 90psi in my 25mm Rubino pro's for commuting and winter mileage. And I prefer the feel of the fatties, so may go with them on the race bike when I wear out the pro race 2's.0 -
The aero advantage of narrow tyres is a myth - as Pinarellofan says, the aero advantage is negated by the energy losses from the greater deflection of the narrower tyre carcass. 20 years ago I too was under the illusion of the narrower-is-better, but over the years I've gradually switched to 23s and now 25s, when I can get them to fit. I've also reduced my tyre pressure too for improved feel and comfort - particulalry when cornering in roadracing. I took some cues from people I know who raced professionally in Belgium, where fat tyres and lower pressures dominate. Narrow tyres at higher pressures probably means less comfort, poorer grip and a greater chance of punctures.Make mine an Italian, with Campagnolo on the side..0
-
What would they class as lower pressures Monty?
it's a hard life if you don't weaken.0 -
-
Hi there.
Some thoughts.
1) Aerodynamics is not a myth!
2) Lower pressures are used in Belgium cos they have come cobbled roads there.
3) Higher pressure is better where you can find some smooth tarmac - especially when TT and you can pick your own line.
4) A tyre at 120psi will roll faster than the same tyre at 100psi as the contact patch is less and less rubber deforms.
5) I defy anyone to corner in the dry, at a speed where a 23mm tyre will slide out and a 25mm won't
6) If it's wet it worth knocking back the pressures by 10psi or so. Same again if the roads are rough.
7) Tyre choice is a compromise of all of the above!
Personally I pick 23mm tyres at 115psi for dry road racing, and 20mm tubs at 160psi for time trialling. Commuting bike gets 25mm tyres at 100psi.
Take your pick - for the your conditions.
Cheers, Andy0 -
Zipp do their own tyre now and they claim 21mm is best for combining aerodynamics and rolling resistance. Personally I use 23s but mainly because that's what everyone else uses - never tried 25s - I had some 28s once and I thought they felt significantly slower - though they weren't a race tyre so it may be an unfair comparison.
it's a hard life if you don't weaken.0 -
I have fitted specialized 23\25 roubaix tyres on my Allez instead of 23 conti gators. They are more comfortable on my commute and certainly absorb more vibrations.
Can't say I have noticed any difference in rolling resistance whatsoever. If anything I think i am travelling a bit faster because its less harsh over rough tarmac. The roubaix tyre is a combination of a 23\25 tyre :-
"The Roubaix Pro clincher is the easiest, fastest way to turn long & fast rides into long, fast, comfortable rides. In a unique construction design that merges a faster 23c wide tread with a more comfortable large-volume 25c casing, this tyre offers a fast rolling, great handling tyre which damps road vibration and increases riding comfort without sacrifice."
I'd say thats a pretty fair description0 -
I'm now using 25's rather than 23's where I can.
Don't notice any difference in speed and 25's are much more comfortable.
I'll be riding the Marmotte on 25's this year (pro Race 3's if I can get 'em !)0 -
System wrote:I've got Vredestein Fortezza Tricomps which seem to like a little more pressure compared to others as they are quite supple and feel a little soft at lower pressures, so Ive got 130 in front and 140-150 in back (they are rated to 175). I'm close to 112kg though so need a bit more pressure than most and I like a less spongy ride.
If your going to do a sportive with long decents in groups I woul lower pressure to at least 90lbs to stop punctures from "hot" rims from brealking
Hight pressures are ok for track and TT but not really for general riding.I use 100 psi for racing, and 120 for track.
I have been known to go as low as 25 on some rides, mainly because I did not notice the slow punctures !!0 -
oldwelshman wrote:If your going to do a sportive with long decents in groups I woul lower pressure to at least 90lbs to stop punctures from "hot" rims from brealking
Hight pressures are ok for track and TT but not really for general riding.I use 100 psi for racing, and 120 for track.
Hi there.
No offence ow, but have you looked at the physics of exactly how hot the air inside your tyre would have to get to increase the pressure by the 10psi you're talking about?
It's never going to happen!
Cheers, Andy0 -
ps No-one has mention another _major_ benefit of riding higher pressure tyres. Snakebite punctures are much, much rarer at 120psi.0
-
andrewgturnbull wrote:ps No-one has mention another _major_ benefit of riding higher pressure tyres. Snakebite punctures are much, much rarer at 120psi.
Snakebites are the majority of my unplanned deflations. It's rare for something to penetrate the tread and carcass except on a tyre that's reaching the end of it's useful life.0 -
andrewgturnbull wrote:oldwelshman wrote:If your going to do a sportive with long decents in groups I woul lower pressure to at least 90lbs to stop punctures from "hot" rims from brealking
Hight pressures are ok for track and TT but not really for general riding.I use 100 psi for racing, and 120 for track.
Hi there.
No offence ow, but have you looked at the physics of exactly how hot the air inside your tyre would have to get to increase the pressure by the 10psi you're talking about?
It's never going to happen!
Cheers, Andy
Oh well I guess you know more than the pro riders
I guess Greg Lemond is also wrong in advising people to lower pressures for long decents whils in groups when your braking a lot and rim temperature gets very high.
I also suppose that was not the reason why most of the puncture in those types of rides are on decents?
I stand corrected.
By the way I never tried the calculation but I suspect that if the volume of the air remains costant, then an increase in temperature increases the pressure.
from what I can vaguely remember from school many moons ago, the pressure is directly proportional to the temperature provideing the volume remains constant? I think. 0
