# 23 vs 25



## kane (Jun 2, 2010)

I'm getting ready to order some new conti gp4000s Would I notice much difference one way or the other with 23 vs 25's ?


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## rubbersoul (Mar 1, 2010)

why not split the difference and go with 24s


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## bigbill (Feb 15, 2005)

Make sure a 25 will clear your fork. Otherwise, 25mm tires are great.


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## jhamlin38 (Oct 29, 2005)

if you're a bit hefty, or north of 180lbs, 25's help smooth things out, less pinch flats etc. I find that tubeless 23's have the same cushy feel of 25's.


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## LookDave (Sep 29, 2007)

kane said:


> I'm getting ready to order some new conti gp4000s Would I notice much difference one way or the other with 23 vs 25's ?


Have ridden both sizes of gp4000's extensively, smoother ride at lower pressure with 25's, and notably fewer flats. I weigh 180 pounds.


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## Special Eyes (Feb 2, 2011)

I've been wondering about this. My current tires are noted as being 23/25. What the heck does that mean? They don't look to be as thin as many 23's I see, but I suspect I'm getting a more comfortable ride.


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## AndrwSwitch (May 28, 2009)

I noticed slightly quicker handling on my 23mm tires, and I think I can corner a little harder. I thought I could accelerate faster too, but I doubt that this was a real difference. I don't notice any negative side effects, but I weigh 155 lb and can ride them at "my" pressure without pinch flats. I was also switching from the stock GP3000s to GP4000s when I made that change, so I'm sure that contributed too.


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## maximum7 (Apr 24, 2008)

Do you use the same tire pressure for both?
Like if I use 115psi for 23's, do I use the same for 25's?


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## heathb (Nov 1, 2008)

Go with the 25mm tires, they'll last longer, they give more cushion due to greater volume of air, less flats, easier to change flats. They are faster due to less deflection(meaning deforming of the tire when pressed between the road and rim is less on a 25mm when compared to smaller 23mm) this means the 25mm provides less rolling resistance.

They'll also provide more grip through the corners. 

I'm getting ready to dump my GP4000 S tires that are 23mm on ebay as my 25mm tires that I've been riding for the past couple of years are better all around. 

Some pros are even jumping to the bigger 25mm.

Tire pressure can be reduced on a 25mm to 90-110 psi. I ride mine at 100psi and I'm 6'2" 164lbs.


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## pagey (Oct 30, 2009)

I love the ride of 25s running 10psi less on my S2


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## wim (Feb 28, 2005)

maximum7 said:


> Do you use the same tire pressure for both?
> Like if I use 115psi for 23's, do I use the same for 25's?


The whole point of having slightly larger tires is being able to run them at slightly lower pressures to gain some comfort. If you'd run the same pressure in both 23s and 25s, the 25s would actually be less comfortable. The often-repeated "less rolling resistance" thing is not that simple: it's only true at identical tire pressures—a fact often left out or buried in the fine print of popular literature on this subject.


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## R3 Sloth (Mar 25, 2010)

I personally don't like the 25 enough to change. It's purely aesthetic for me. I believe the ride is a bit smoother on the 25 but not so big that I'm going to change.


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## Lectron (May 29, 2005)

Other than 25s giving increased comfort and decreased rolling resistance I really hate'em......


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## kbwh (May 28, 2010)

FWIW. I have been training on Conti GP 24mm the last couple of weeks. 6 bars front, 6.3 rear. The comfort level is significantly higher than the old worn out 23mm Michelin Prorace they were replacing. I ran those at 6.5/6.8 bars. I'm 73 kg.

Have ordered a pair of 25mm GP4seasons for my old steel spoked Campagnolo Eurus wheels. The idea is to use those on our local equivalent of Tuscany's strade bianche. Normally the Euruses have 23mm Michelin P3R on them, and used to be my preferred race wheels.


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## heathb (Nov 1, 2008)

R3 Sloth said:


> I personally don't like the 25 enough to change. It's purely aesthetic for me. I believe the ride is a bit smoother on the 25 but not so big that I'm going to change.


Think of the bigger wheel like a skateboarder does. A slightly bigger wheel from 56mm to 60mm is quite a bit faster. 

I remember back in the day ramp skating and we went from 66mm to 50mm in the span of a decade and then they went back up. Those 50mm wheels sucked big time and were slower then all get out. 

Same thing with cycling wheels. Add a few millimeters and you'll actually pick up a little speed. Though you can end up going too big and adding weight, which will slow you back down.


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## kane (Jun 2, 2010)

Well I only weigh 150 and normaly ride my 23's at 100psi front 105 rear. What I was tring to figue at was if the 25's would have more grip in the corners, and less rolling resistance, and if it's enough to make up for the added weight of the 25's over 23's???


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## bigbill (Feb 15, 2005)

kbwh said:


> FWIW. I have been training on Conti GP 24mm the last couple of weeks. 6 bars front, 6.3 rear. The comfort level is significantly higher than the old worn out 23mm Michelin Prorace they were replacing. I ran those at 6.5/6.8 bars. I'm 73 kg.
> 
> Have ordered a pair of 25mm GP4seasons for my old steel spoked Campagnolo Eurus wheels. The idea is to use those on our local equivalent of Tuscany's strade bianche. Normally the Euruses have 23mm Michelin P3R on them, and used to be my preferred race wheels.


I did a ten hour double century (203 miles) on 25mm Four Seasons. I'm a big fan of 25mm tires but unfortunately my newest bike won't fit a 25 on the front and my Peg with a Reynolds fork won't clear all brands of 25mm. It cleared the four seasons just fine.


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## djetelina (Oct 9, 2007)

rubbersoul said:


> why not split the difference and go with 24s


Second the motion. Dumped my 25mm Michelin Krylion's a year ago, picked up some 24mm Vittoria Open Pave's. Never looked back.


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## kbwh (May 28, 2010)

Only trouble with those is that green colour. Total clash with Celeste...


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## wim (Feb 28, 2005)

heathb said:


> Think of the bigger wheel like a skateboarder does. A slightly bigger wheel from 56mm to 60mm is quite a bit faster.


I think you're confusing diameter and width. The "23" and "25" referred to in this thread are tire _width_ ("section") dimensions in millimeter. As far as I know, the 56- and 60 mm in skateboarding refer to wheel _diameter_. Correct me if I'm wrong. I'm 69 years old and never skateboarded. I might give it a try one day, though.


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## Mersault (Jan 3, 2005)

Special Eyes said:


> I've been wondering about this. My current tires are noted as being 23/25. What the heck does that mean? They don't look to be as thin as many 23's I see, but I suspect I'm getting a more comfortable ride.


I have been riding on Michelin Pro Race 23s for years. I recently bought some Maxxis Re-fuse tires in 23. Mounted them both up, and well the Michelin looked bigger, but I had been riding them for so long I didn't really notice before. I take out my calipers and measure the width of both brands while inflated on the rims. The Michelin come out to nominally to 25mm while the Maxxis came out to 23mm. While the Maxxis where a little harder to mount, and I've only used it in the rear wheel, I haven't noticed a difference in my ride. That said, I think I may order the Maxxis in 25mm next time around. I'm currently running a Michelin in the front which is wider than a Maxxis which is in the back. I switched over to the Maxxis Re-Fuse for a supposedly longer lasting tire, time will tell on that one.


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## heathb (Nov 1, 2008)

wim said:


> I think you're confusing diameter and width. The "23" and "25" referred to in this thread are tire _width_ ("section") dimensions in millimeter. As far as I know, the 56- and 60 mm in skateboarding refer to wheel _diameter_. Correct me if I'm wrong. I'm 69 years old and never skateboarded. I might give it a try one day, though.


There's an increase in diameter with the 25mm tires as well at least with my Conti's.


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## AndrwSwitch (May 28, 2009)

Yes, there's an increase in diameter from 23mm to 25mm. But, for an entire wheel with a diameter around 670mm, it's maybe 3mm. In absolute terms, maybe pretty close to a difference that's significant to a skateboard. But relative to the total size of the wheel, I don't think it's important.


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## brucew (Jun 3, 2006)

Special Eyes said:


> I've been wondering about this. My current tires are noted as being 23/25. What the heck does that mean?


My Nokian W106 studded snow tires are 35/38. They're the width of 35s and the height (diameter) of 38s.


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## djetelina (Oct 9, 2007)

kbwh said:


> Only trouble with those is that green colour. Total clash with Celeste...


Agreed on the green color, can be kind of hard to stomach for the rider and those around him/her. I looked around a bit and got the all black Open Pave's: 
http://www.excelsports.com/main.asp...x24mm+290tpi&vendorCode=VITT&major=1&minor=27

Fairly easy to find, a little harder to pay for. But roll really sweet.


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## ZoSoSwiM (Mar 7, 2008)

GP4000's in 25mm are crazy smooth and super grippy. I noticed a lot of improvement in ride feel when I swapped to them over the 23mm kendas I was running. Since then I've lost a lot of weight and have switched by to Ultremo ZX's in 23mm and they feel the same but a bit faster. Are they? I don't know! I like them though.

Honestly.. I think the difference between 23 and 25mm is small.. if you weight more the 25's will be a little more forgiving because there is more air inside the tire.


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## Fixed (May 12, 2005)

*not much*



kane said:


> I'm getting ready to order some new conti gp4000s Would I notice much difference one way or the other with 23 vs 25's ?


For smooth roads, no reason to run more than 23. For bumpy roads, I'd run 25. That's how I look at it.

Not a lot of difference, though.


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## Hank Stamper (Sep 9, 2009)

Order both and see which you like for yourself.

Tires wear out and the difference you feel (if any) certainly won't be so great that the size you like least will be a wasted purchase.

25 rear 23 front is also something you can try.


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## F45 (Nov 25, 2010)

Fixed said:


> For smooth roads, no reason to run more than 23. For bumpy roads, I'd run 25. That's how I look at it.
> 
> Not a lot of difference, though.


Me too. There's a route out here that goes to cliche and limestone for a few miles. I ride 25 on the front and 28 in the rear. If all the roads were smooth I'd ride 21. The bigger tires seem easier to find in "thick and heavy" versions for training. My rate of getting flats dropped dramatically with that 28 in the rear.


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## clayton.cole23 (Feb 25, 2011)

:blush2: deleted by me, wrong post in wrong thread. :blush2:


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## ziscwg (Apr 19, 2010)

kbwh said:


> Only trouble with those is that green colour. Total clash with Celeste...


I'm putting some on my red Cannondale CAAd10 at Christmas so I can be in the Christmas spirit when I ride........................

The used to make black ones, but when I talked to the rep at Sea Otter, he said they stopped with the black ones.


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## Cut.Aussie (Mar 19, 2011)

Have been riding 4000S in 23 but with a new bike then new wheels I decided to give 25mm 4000's a go and love the little bit more comfort they offer and they still corner great.


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## Sablotny (Aug 15, 2002)

I changed form 23mm Michelin Pro Races to 25mm Vittoria Rubino Pro's for the winter. I was running the 23's at 115 psi and the 25's at 105. I've found the 25's to take the edge off bumps very nicely, and I don't feel any slower. Pretty sure I can corner harder on the 25's as well. Might not be going back!


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## terbennett (Apr 1, 2006)

Sablotny said:


> I changed form 23mm Michelin Pro Races to 25mm Vittoria Rubino Pro's for the winter. I was running the 23's at 115 psi and the 25's at 105. I've found the 25's to take the edge off bumps very nicely, and I don't feel any slower. Pretty sure I can corner harder on the 25's as well. Might not be going back!


This is something to consider. However, did you try the Vittoria Rubino Pros in a 23? You not only changed tire sizes but you changed brands as well. That could be an even bigger factor.


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## terbennett (Apr 1, 2006)

I've ridden both GP4000s and I'm 215 lbs. I couldn't tell the difference at the same psi.


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## AndrwSwitch (May 28, 2009)

terbennett said:


> I've ridden both GP4000s and I'm 215 lbs. I couldn't tell the difference at the same psi.


This defeats the purpose of using a larger tire - you can use a lower pressure and not get pinch flats. If the pressure you like in a 23mm tire doesn't give you pinch flats, IME, there's not much benefit to a bigger tire.


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## onespeedbiker (May 28, 2007)

Special Eyes said:


> I've been wondering about this. My current tires are noted as being 23/25. What the heck does that mean? They don't look to be as thin as many 23's I see, but I suspect I'm getting a more comfortable ride.


The 23c/25c Roubaix is a Specialized tire (I think made by Vittoria); also known as the Specialized Works and Pro. I really like these tires, which have a reputation for flatting that I've never experienced. The idea is to have a 23c tread on a 25c casing. What this looks like is a raised 23c area on the surface of a 25c tire (see photo; the yellow tire is a Gp4000s 25c). It may look a little funky, buts it's a very comfortable and stable tire. I especially like the fact that they continually show up on the take off table for 1/2 price because new bike buyers usually want a better known tire:thumbsup:


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## mikagsd (Mar 22, 2008)

I have a 2010 Roubaix & put the Roubaix S Works 25's on mine and love the feel. Made a nice difference in my ride quality. Don't think you will regret it.


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## haydeno (Apr 26, 2011)

Going from 23 to 25 I didn't notice a difference, 25 might last longer than 23 due to higher surface area too


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## H.Bicycletus (Apr 16, 2006)

All this talk of 23 vs 25 tires and no mention of rims? Any educated opinions on 23mm rims like HED Belgium C2s or Velocity A23s mated to 25mm tires?


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## mikagsd (Mar 22, 2008)

Fwiw my 25s are mounted to kinlin xr300s w chris king classic blue hubs 32r/28f. Love the ride.


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