Tyre size 23 v 25

User avatar
Dave R32
Posts: 773
Joined: Tue Nov 18, 2008 8:12 pm
Location: North Lakes - Brisbane

Re: Tyre size 23 v 25

Postby Dave R32 » Tue Jan 21, 2014 4:57 pm

Roub wrote:My verniers say 26mm wide - and these are on 24mm (external) Roval CLX40's


Thanks for that. I will be fitting them on Velocity A23 rims which are 23mm wide so I think they will fit.....only one way to find out for sure !

Cheers
Dave.
Avanti Vivace = Sold | Trek Madone = Cracked | '12 Caad10 = Sold | Pinarello SDG3K | '14 Caad10 & Bianchi Pista

AndrewCowley
Posts: 306
Joined: Sat Jul 20, 2013 1:57 am

Re: Tyre size 23 v 25

Postby AndrewCowley » Wed Feb 12, 2014 7:00 pm

I'm a newbie to this. In terms of clearance, how can one tell if 25 tyres will fit or not? Is the main concern the brake caliper or the frame? Or both? My bike has Shimano R561 calipers.

mikgit
Posts: 753
Joined: Fri Jul 27, 2012 8:26 pm
Location: Launceston

Re: Tyre size 23 v 25

Postby mikgit » Wed Feb 12, 2014 8:16 pm

I guess, assuming you are running 23's now, take a look at all the points (frame/fork crown/calipers) and see if there is a bit of room right now or not much. If it is already a tight squeeze, then maybe no, other wise, try em and see I suppose.
I've only ever run 25's (swalbe durano and conti 4000s) and they seem good, had a blowout in the 1st 100km with the 4000s', but that was glass, otherwise nbo issue but I prefer the feel of the conti's over the swhal...whatever they are called.
Look 675 Pro Team, Cervelo R3, GT Xizang, GT Zaskar, Scott Spark 710, Yeti ARC, DiamondBack Apex

AndrewCowley
Posts: 306
Joined: Sat Jul 20, 2013 1:57 am

Re: Tyre size 23 v 25

Postby AndrewCowley » Wed Feb 12, 2014 8:20 pm

mikgit wrote:I guess, assuming you are running 23's now, take a look at all the points (frame/fork crown/calipers) and see if there is a bit of room right now or not much. If it is already a tight squeeze, then maybe no, other wise, try em and see I suppose.


Thanks. Are 25's taller than 23's or is width the only difference?

mikgit
Posts: 753
Joined: Fri Jul 27, 2012 8:26 pm
Location: Launceston

Re: Tyre size 23 v 25

Postby mikgit » Wed Feb 12, 2014 8:26 pm

i believe taller (could be wrong) as well as wider. I know I was a bit worried about the crown on my R3 fork, but they seem to fit OK, came with vittoria something 23's and there was not much room... so far so good.
I run somewhere from 100 to 110 psi (usually 105) depending on how much I i can be bother to put in that last pump... :?
Look 675 Pro Team, Cervelo R3, GT Xizang, GT Zaskar, Scott Spark 710, Yeti ARC, DiamondBack Apex

User avatar
Dave R32
Posts: 773
Joined: Tue Nov 18, 2008 8:12 pm
Location: North Lakes - Brisbane

Re: Tyre size 23 v 25

Postby Dave R32 » Thu Feb 13, 2014 11:23 am

Some interesting information in the later part of this article.

http://www.competitivecyclist.com/learn/25-vs-23

Cheers
Dave.
Avanti Vivace = Sold | Trek Madone = Cracked | '12 Caad10 = Sold | Pinarello SDG3K | '14 Caad10 & Bianchi Pista

kenwstr
Posts: 494
Joined: Tue Apr 23, 2013 8:21 pm

Re: Tyre size 23 v 25

Postby kenwstr » Thu Apr 03, 2014 9:57 pm

AndrewCowley wrote:I'm a newbie to this. In terms of clearance, how can one tell if 25 tyres will fit or not? Is the main concern the brake caliper or the frame? Or both? My bike has Shimano R561 calipers.


Hi,

I haven't read the whole thread so don't know what your wheels are. Assuming your talking about clinchers, the determining factor is the inside width of the wheel rim. If the tyre is too big for the rim, it will tend to role or pop off the rim. If the tyre is too small, you risk damaging the rim on bad road surfaces, potholes etc. Tyre pressure relates to weight (15% deflection or so). As weight goes up so does pressure until you get to a point that is beyond the tyres or rims capacity. Your better off going to a wider tyre at lower pressure before that point. There is fairly wide rang of tyres that will fit on each rim width but there are limits. Google the subject and look on Sheldon Browns website, there is a chart, actually he has charts and much to say on most subjects. Also Shimano state tyre size ranges for their rims, maybe other manufacturers do as well.

I'm pretty sure more than a few will find this a bit controversial, all I can say is I think the principals are sound even if there is disagreement on actual final figures. I tried lowering pressure on my front wheel and the bike is faster and a lot smoother over rough surface. The rear was already about right, perhaps a little higher than the 15% recommends but I haven't had time to experiment with that much yet. There's a chart for tyre width, loads and pressure too, just Google.

Regards,
Ken

ironhanglider
Posts: 2343
Joined: Fri Apr 17, 2009 9:44 pm
Location: Middle East, Melbourne

Re: Tyre size 23 v 25

Postby ironhanglider » Fri Apr 04, 2014 4:44 pm

Whilst Ken is talking about tyres v rim, the limits will be whether your tyre rubs on something or not. Whether the tightest point is at the brake bridge, the seat tube or the chain stays will depend on the design of the frame and the trueness of both the wheel and the tyre.

Spin the wheel to find the tightest spot, and measure the clearance you have there at the moment (with your tyre at full pressure) if you have more than 5mm clearance at these points (particularly at the chain stays to account for wheel flex) then going from 23 to 25 in the same tyre will be doable. Not forgetting that tyre manufacturers seem to use different non-standard rulers, so don't believe what is written on the side. A 23mm Continental is unlikely to be the same size as a 23mm Vittoria (or anything else).

As with anything don't just put the new tyres on and go, have a final check before the first ride. New tyres always seem to stretch a bit too so what may just clear today may be rubbing by next week.

Cheers,

Cameron
Image

Who is online

Users browsing this forum: No registered users