Are there any drawbacks to using 23mm tires on my rim which is designed for 25mm tires?

Do I lose the benefits of 25mm tires? Does it stretch out the 23mm tires in an awkward way?

What rim so you have that is designed for 25 mm tires? Usually rims cover a wide range of tire sizes. The numerical width of the rim does not suggest that only that same width tire is suitable. Tell us more about what you have. What is the outside width across the top of the brake track? What is the inside width?

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Ah, sorry they're Fulcrum Racing 5 LG with an external width of 23mm. Guess there shouldnt be any notable differences if the tire and the rim are the same. I'm probably just OCD for no good reason.

fulcrum 5's will handle 23's just fine, nothing to worry about

I'm riding with a 23mm tire on my front wheel, which is a 25mm wide HED Ardennes Plus. It rides and handles beautifully. I would use a 25mm tire (as I do on my rear wheel) if I could, but there's too little clearance with my front brake on my particular bike. If there's enough clearance on your bike, I would go with 25mm tires.

+1. I have the same problem on the front with my SRAM Red brakes. I still have a 25 on the rear.

You can use that rim for 23 mm tires on up to at least 28 mm, probably 32 mm, but don't take my word for it on the 32s. As compared to a 19 mm rim (the old standard), all tires on your rims will measure larger than their nominal size. The 23 mm tires will be more like 25 mm tires on a 19 mm rim. So you have to be sure that you have enough clearance on your frame for the slightly larger size. That increase in size also translates to the ability to inflate the tires to a lower pressure without risk of pinch flatting your tubes. That will give you more comfort than with a true 23 mm tire inflated to a higher pressure. All around a good thing.

I have some 31mm tires around but I think I'll stick to 28 and lower sizes on it but its good to know that I have some breathing room in terms of tire sizes. Thanks for the advice and extra information on clearance/pressures!

Should be okay, but you'll just have to try them. I had some cheaper 23's that worked fine on traditional rims, but just wouldn't stay on my 23mm HED Belgium C2 rims. Seemed like that was too much stretch and the bead wouldn't hold. On my other set, Mich. PR3 23's seem just fine (on 24mm Pacenti SL23 rims)...but that's a nicer tire and runs a little wide.

2013-14 Fulcrum Racing 5's were 20.5mm wide. The 2015 'LG' versions of the 5 and 7 are 23mm wide.

Is that tire on a 23 rim?

Illegal

I'm surprised to hear that about a 23c tire not fitting the C2s. The internal width, or BSW, of that rim is just 17.5mm, not particularly wide, and is well within spec range of 23c fitment.

Your SL23s, however, hit 20.3mm BSW, which is pretty wide, and perhaps a greater width than you'd expect just comparing the simple, external width numbers between it and the C2, which only varies by 1mm. Still, 23c tires should mount fine.

Anyway, besides emphasizing that external width is not the important number to tire fit (but can be important for brake setup), I'm wondering if bead shape might be the explanation for the problem you had, though that's typically not an issue for clinchers; pehaps an out of spec tire?

You fit in nicely, here.

The bead on both tires had issues holding on several attempts. I guess they were cheap stiff tires with a narrow minded bead shape? I never tried 'em on my Pacenti's.

This little one has had a pair of the Fulcrum 5 LG’s since April. Things have not gone so smoothly, literally. See post #10

Regarding this post: Much digging was done before this purchase as I was keen to unveil the difference between the (defunct?) 5’s and the new 5 LG’s (C17). rpenmanparker (04-24-15, 03:37 PM #8 ) covered this pretty comprehensively. Reporting official blurb, a measure of hard evidence and a pinch of rumour what emerged is that the 5 LG’s compared to the 5’s were redesigned to allow for easier fitting of ≥25mm tyres, which presumably certain individuals want for various reasons; too numerous to mention here. Interestingly I note that the professional peloton are (increasingly?) using 25mm tyres as appropriate and apparently rim design, generally, is reflecting this.

Something rpenmanparker didn’t explicitly mention, though it was implied, is that the contact patch for a given tyre will increase. Apparently good for comfort and decreased tyre wear!

Yes, these wheels are also marketed as Campagnolo and yes, this post also applies to the Fulcrum 7 LG’s.
Indirectly related hilarious recollection: mounting 35C’s, with studs, onto track bike with track wheels. True story.


Please, can anyone help me remove the axel of the 5 LG’s? (internal link)

I do not understand what you're talking about, but I don't like the suggestion that a rim could be designed to ease fitting of 25c tires over 23c tires, if that indeed is what you're suggesting.

Then sir, I must challenge you to a duel! *reaches for glove*