I'm purchasing my first proper road bike after a year or so of slowly increasing my cycling and was wondering how unusual it is to have 25" wheels on a road bike and what sort of differences this will make to the bike in terms of handling and comfort compared to what I gather are the more conventional 27"ers.

Thanks

Spelling is key.

Kicked myself as soon as I posted, didn't think to check the title... Can't find a way to change the whole thread rather than just the post title.
Apologies.

Where are you going to find replacement tires and tubes for 25" wheels?

Where are you going to find wheels, tubes, and tires that size?

What are 25" wheels? The old (and mostly useless inch designations) would be 28" for most road bikes and 26" for 650c.

Contemporary bikes use 700c (which is XX x 622). Some Tri bikes and specialty bikes (designed for VERY small sizes) use a 650c front wheel (which is XX x 571). Have a look at the tire and see if you can find numbers that resemble those. If not, what do you see?

25"? Highly unusual. I think you can still get 24" road tires, maybe...

Paselas in 24x1"

So I'm sure you could have a custom frame built around some 24" wheels.

A friend of mine used to have a Bianchi with a 24" front wheel, much like Terry designs, dunno where she got slicks for that but I'm sure slicks are still out there.

There are a few 20" road bike options out there. Bike Friday. Moulton. That's all I can think of off the top of my head.

I like the Bike Friday. Never tried a Moulton but heard good things.

The whole folding bit is a nice bonus.

Here's a pic of a Bianchi like my friend had:

I had difficulty finding info on them but didn't realise they were that rare. It's possible the seller isn't as knowledgeable as he's making out. I'm going to see the bike before purchasing (it's not in my possession yet). I'll check myself for any numbers. Thanks for the warning and info.

Never seen a bike with different sizes front and back like that Bianchi, why would they do that? (This one definitely has same wheels front and back!).

It's hard to say how the seller came up with the 25" wheel number. 700c rims are just a little over 25" in diameter, so maybe that's what it is. All wheel sizes are pretty much jibberish because they consider rim and tire in the size. See this chart for reference. (oooh, forgot that road 24" was different from MTB 24") Just the wide variety of 26" rim sizes gives you an idea of how little most wheel size quotes mean. And there are at least four different 24" rim sizes.

If it's a 25" frame, it's pretty huge! You better have been on your high school basketball team to fit that frame.

The Terry bikes and others like it had the small wheel to make small frame sizes possible. 48-49cm is about the smallest frame you can really pull off with a 700c front wheel. That Bianchi is a 44cm. Seems like junior road frames with 24" wheels front and back used to be somewhat common, not so much any more.

That's why the old designations are no longer used in the industry. All tire/rim/tubes are designated by the ETRTO numbers (example: 622 x 13). Those are very specific and refer to actual measurements.

The traditional thinking is to use the largest wheels you can fit within a frame. For a med road bike, this is 700c. You can fit them into larger frames but when you try to squish them into smaller frames you need to bodge with the geometry.
The largest wheel a bike designer should fit into a nice small frame is 26" (the 650c size).
Some makers of v small bikes use smaller front wheels (24/700c). Terry Precision pioneered this feature. It helps keep the reach from saddle-bars short enough.

It is possible to design bikes taking smaller wheels. Triathlon bikes went through a 650c trend. Moulton make some fine 20" bikes with full suspension (done properly for the road, not MTB style). There are some performance folders taking 24 and 20" wheels.

Some bikes take the MTB wheel size in a road/touring-bike frame. This gives a nice selection of medium tyres which are lacking in the 650c size.

If you are taller than 5'4" then the wheel size debate is not necessary. Get 700c. Everybody on the road uses it, it works well, you can get the parts anywhere at a good price. Anything else is boutique and specialist.

Perhaps someone is mis-reading the size printed on the tire. 99 % of Full size road bikes have 700c tires. Some triathlon bikes use 650c tires.
However, tire widths come in 23mm, 25mm, 28mm .... so maybe it has 700c wheels with 25 mm wide tires, which is normal, which will show as "700c x 25" or similar

Good point Homebrew, the bike could be shod with 25s and the seller took that to mean 25". Hopefully if the OPs looking at a roadbike it has 700c wheels, or at least a somewhat reasonable road bike wheel size.

Got any pics, Nemode? Don't share entire ad if you're in a hot city, cuz it might get swiped.

Sounds very reasonable that the seller might be misreading the width or measuring diameter and rounding down. I'm expecting it to be a pretty normal, if slightly older road bike. The attached picture is the bike, I believe it's a Carlton Kermesse from ~1980.

Thanks a lot for the reassurance.

Edit: Oh also I made sure to check frame size as I'm no giant and it's definitely a very manageable 55cm!

Nice ride! 55-56cm sounds like a good frame size estimate. Most likely 700c wheels. 15% chance of being 27" wheels.

27" is still pretty easy to find tires for, just not as much choice. If the price and fit are right I'd go for it!!!

That looks really odd.

Yes the Terry style action looks odd. But how else you gonna make a reasonable 44cm bike?

49cm bikes with 700c wheels have insanely short headtubes.

And just to confuse things, there's 650b.

Small front wheel bikes were common in the 1980s. Because of the difficulty in finding spare tires and wheels, all the major manufacturers now use 650 wheels (front and back) for their smaller sized bikes. 650 tires are not as common as 700, but you should be able to find at least a few in stock in most cities (while the old 24" tires were pretty much mail-order only and not cheap).

Looking at the Terry web site, they appear to have finally switched to 650 wheels as well. For a long time, they were holding out as a marketing gimmick.

As I note above, 650B is an option--front and rear. There is not just one "650"--there's 650A -B and -C. You are referring to 650C and these have fallen out of favour. Meanwhile, 650b is thriving, thanks to development of new high performance tires, with two new options in the last year from Pacenti and Grand Bois ... and many custom builders designing for the size.

I don't see anywhere where the OP tells us what kind/brand of bike she/he is buying.

is it possible the OP and or seller is confusing a 700x25 tire as being a 25" wheel?

cool Sport SX they only made them two years.

Post #16. Sweet ride.

Haha, thanks Lester.

Been and bought it now and they are the standard 700c wheels, so no regrets. Thanks for the help everyone. Now I can start worrying about which tyres I want from the massive selection....