Bicycle Mechanics - Current tyres for a 27 x 1.25 wheel

Hi there, you'll have to excuse my lack of knowledge here - I am very new to all this. My bike wheels say 27 x 1.25 and I would like to use a pair of michelin tyres marked 700c by 23c. Is this possible? If not, what do these sizes actually mean? Is one in inches and one in c's, whatever that means? If so, what size are my bike wheels in c?

Thanks in advance.

Kathy.

700c are smaller than 27 inch - therefore they most likely will not fit the rim.

Read http://www.sheldonbrown.com/tire-sizing.html to learn about the differences - there is a chart on this page with measurements - I think it says that there is a 8mm difference.

Or here for just a chart - http://www.bikecult.com/works/wheelsizes.html

You may have a little trouble finding 27 inch tyres - but I would say that most bike shops could at least order some if they did not have any on hand. I don't know - as I find that the black rubber tyres from K-Mart (Australia) for $16.00 are very hard wearing - They also have Dunlop gumwalls in this size, but they dry out and crack too quickly.

You must use 27 X 1 1/8 or 27 X 1 1/4 tires on your rims. 700c Tires are 8mm smaller in diameter so you would never get them on 27" rims. Just purchase 27 X 1 1/8 or 27 X 1 1/4 tires from your LBS or online from an Internet bicycle dealer. Most X-marts still stock 27 X 1 1/4 tires as well. I've never understood this, as bicycles with 27" wheels/tires haven't been sold for quite a few years now. Wal-mart has even started selling bicycles with 700c tires but does not stock replacement tires for those bicycles.

Sorry, the 700 tires fit only 700 rims. You need 27 inch tires to fit your bike's rims. The 700 is metric (millimeters) and it works out to a smaller bead diameter than the 27 inch (27x1.25) wheels.

There's no shortage of tires to fit your current wheels. It is also sometimes possible to fit size 700c wheels to bikes originally equipped with 27s, allowing a greater variety of tread types to be used. This will require some adaptation of the brakes, whose pads might not extend far enough to reach the braking surface of the smaller diameter wheel. Only you can decide if that's worth your time and trouble.

27" and 700C wheels and tires are not interchangeable. 700C wheels (ISO 622) are, as noted 8 mm smaller in diameter than 27" (ISO 630).

The nomenclature of bicycle wheels is old and often confusing. The "700" wheel size is an older metric designation for tires that, at one time, came in three different widths known as 700A, 700B and 700C. The A and B tires are obsolete but the size 700C is still around although it now is used to refer to a rim size, not a tire.

The Sheldon Brown article referred to above explains all of this in detail and also explains the current ERTTO/ISO designations that have brought some order and uniformity out of the former chaos.

Hi there, you'll have to excuse my lack of knowledge here - I am very new to all this. My bike wheels say 27 x 1.25No they don't.

They may say 27 x 1 1/4".

Although that's mathematically equivalent, it is very dangerous to try to translate decimals to fractions or vice versa when talking about bicycle tire sizes.

Sheldon "http://sheldonbrown.com/tire-sizing" Brown

Oooops, sorry about that over-sight - you are right of course, they say 27 x 1 1/4. You lot will probably hate me for even suggesting this, but if for some reason I managed to sweeze a pair of 700c tyres onto my 27" frame (say for example my frame is slightly under-sized or my tyres are particularly stretchy), could I leave them on there without any problems? I only ask because i've squeezed a 26inch inner tube into the tyres before without any problem.

As an explanation as for why I am so keen to get the 700c onto my wheels, I've found a pair of michelin red and black race tyres for $20 for the pair 700 x 23c and want them BAD!

Sorry, its a girl thing!

All help and advice is much appreciated!!!

You lot will probably hate me for even suggesting this, but if for some reason I managed to sweeze a pair of 700c tyres onto my 27" frame (say for example my frame is slightly under-sized or my tyres are particularly stretchy), could I leave them on there without any problems? I only ask because i've squeezed a 26inch inner tube into the tyres before without any problem.

No, forget it. Sorry. Inner tubes are completely different from tires in terms of how they're installed and what function they perform. If you're going to stick with the 27" rims, you have to stick with 27" tires. It might be possible to use 700c rims on your bike, but you'd be opening a whole 'nuther can of worms with that. As for the inner tubes, I'd recommend against stretching the 26ers over your 27" rims. It can be done, but they're really not meant to be stretched over a rim that much bigger than their intended size. As for 700c and 27" inner tubes, they're close enough in size to be completely interchangeable as long as the width roughly matches (i.e, 27 1/4" is approx. the same as 700 x 32c, etc.). Not so for tires, though-

edit: I assume when you say "frame" in your post above, you mean "rim.":)

If you can fit 700C tires on a 27" rim, you're a LOT stronger than us mere mortals!

Ha ha. I get the point. I suppose even 8mm can make all the difference. Thanks for all your help. If anyone spots an online shop selling red 27inch tyres - let me know!

Cheers, Kath.

8MM may or may not sound like much, but we're talking diameter. Multiply that by PI (3.1416) for the circumference and now we're starting to discuss some serious distance! You'd have to "stretch" the tire about 25MM or an inch.

ISTR, RED 27" tires being mentioned in the C&V forum a couple months back???

If you can fit 700C tires on a 27" rim, you're a LOT stronger than us mere mortals!

I have enough trouble fitting my 700c Vittoria tyre to a 700c wheel.... I have broken many tyre levers and have spent many hours of frustration with that one (have now changed to metal tyre levers btw)

Good news guys - my back wheel buckled the other day (ok, not great news) so I am buying some new wheels - 700c. And it turns out that my brake bracket things are adjustable so I'll be able to fit 700c wheels to the frame - I think it will prevent a lot of problems in the future with buying tyres. And it means I can buy those bargain red and black tyres! Thanks for all the advice guys - you have convinced me that 700c wheels are the way to go. Curse the day Dunlop invented the 27 x 1 1/4 wheel! More hassle than they're worth.