Touring - Tire and rim size compatibility...HELP!!!

I have a 1989 Cannondale ST400 that I'm trying to get ready for a 4,000 mile ride NEXT WEEK (eek!). I've been looking for the right kind of tires and I've ended up settling on Continental. Here's the problem: The tires that came on the rims when I bought it are ancient. They were Matrix Isotech 2 tires and they were 27 x 1 1/8. Now, I went to REI to look for some tires (not the ideal place to look for tires, I know) because it was nearby and the guy there told me that that size of tire is simply not produced as much as it was twenty years ago and that I'd have to go to a specialty shop to find tires that size.

Is this true? Are 27 x 1 1/8 tires for touring difficult to find? Does Continental, Vittoria, Armidillo make tires that size? Can a 27 x 1 1/4 tire fit the rim I have if a 27 x 1 1/8 did? What about a tire that is 700 x 23/25. Most of the tires at the REI store were 700 x 23/25c. Would that size be compatible with a rim that fits a 27 x 1 1/8 tire?

I know these probably sound like dumb questions for those with experience...but I'm not very experienced. I've done one long distance ride and I never had to change a flat or do anything to my bike at all. Just looking for an education on this. Thanks in advance!

They may be tricky to find in stock in a store, but there's plenty available online. That's going to make your departure date a little tough, though.

In the past, I've found 27" tires in stock in sporting goods stores that sell low end to mid-range bikes. In this part of the US that means, Sports Authority, Academy, maybe Dick's Sporting Goods, and occasionally, stores like WalMart & KMart will have them. Selection will be limited.

27" tires are for 27" rims. the 1 1/8" figure indicating tire width is less critical, as long as it clears the frame when it's mounted on the bike. For touring, wider is generally better. You cannot use a 700c tire on a 27" rim or vice versa.

If you have a local bike shop you can rely on, you might stop in and see if your bike can be easily converted to 700c wheels. On many bikes, where the brake calipers have enough room to accommodate a 4-5mm move, this is a simple task and opens up a big range of tire choices.

Just out of curiosity I converted millimeters to inches and 700mm=27.56" and 25mm=0.98" which is basically 27 x 1. So, I guess what my question boils down to is will a 27 x 1" (700 x 25c) tire fit and work safely on a rim that held a 27 x 1 1/8" tire? Does the 1/8th inch extra on the tire make such a distinct difference that you couldn't use something 0.125 inches smaller? Or will I just have a harder time getting the tire on, but once it's on it's good to go and safe to ride?

The continental ultra gatorskin is a very nice tire and is made in that size. Google it and you will find plenty of places selling them.

Link here (http://www.biketiresdirect.com/27zz/27in_road_tires/products.htm) for 27 inch tires.

In other words they'd just change the rims?

JSo, I guess what my question boils down to is will a 27 x 1" (700 x 25c) tire fit and work safely on a rim that held a 27 x 1 1/8" tire?

No, 700C and 27" are not compatible.

No.

Thanks, that's what I wanted to know. So the rim is made for 27 x 1 1/8 and that size ONLY.

Thanks everyone. Guess I'll just have to do some searching around for that size.

I think your best bet is to find a local bike Co-Op and see what's available there. There's usually a bit of 27" stock at those places, and expertise that could advise you on converting to 700c is you want to.

edit* here's one in Chicago: http://workingbikes.org/

http://www.therecyclery.org/

700c tires will not fit your rim.
27x1 1/8, and 1 1/4 are not that hard to find, and both will fit your rim. I'd go with the 1 1/4. Conti and Vittoria still make 27s, as do a number of other makers including Panaracer, The Pasela is a good plain vanilla tire. I haven't been able to find any larger tires in 27s, such as 27 x1 3/8, and I suspect that they are no longer being made. Carry a spare tire (folding perhaps)as well as patches and tubes.

schwalbe marathon is another great option in this size.

I would get those, or maybe pasela tourguards for a 4k ride

Nashbar provides fast delivery and is close to Chicago. They list Continental, Vittoria, Panaracer, as well as their house brand in 27". Most are on sale.

These tires are not that hard to fine. You could use either 27 x 1 1/8 or 27 x 1 1/4. Both will work just fine. I would suggest calling some shops around your house and seeing if they have either of these two sizes. If you could, try to get a touring specific tire

27" and 700C are not compatible, but your 27" rims will accommodate other widths. Here's a list of 27" tires stocked by Harris Cyclery (http://sheldonbrown.com/harris/tires/630.html)--it's true that the size isn't nearly as popular as it used to be, and has been mostly supplanted by 700C.

One bit of info that's missing from this thread: 27" or 700c are measures of the rim diameter that a particular tire will fit on. The 23/25mm or 1 1/8" measurement indicates how fat around the tire is. So a 700x23 and a 700x35 will fit on the same rim, but the 35mm tire might be too fat to fit in the frame. And any 27" tire will fit on your current rim, whether 7/8", 1 1/8" or 1 1/4" wide.

Truman's advice on where to find 27" tires is good. Or you could rush order from an online bike shop like Nashbar or Performance.

Or you could rush order from an online bike shop like Nashbar or Performance.

I'd order a couple of spares as well. I live in an area where bicycling is popular and can't think of a single shop that stocks 27" tires. 700c and 26" are all over the place, but not the older 27" tire sizes. If you tear a tire in the middle of nowhere on a 4000mi trip, finding a 27" replacement could be a pain in the neck!

If it were me, I'd want to be touring on a bike with either 700c or 26" wheels...

Wow, thanks everyone for all the input. I went with Continental Gatorskins 27 x 1 1/4 from an online retailer for 90 bucks even, including 2nd day air, which seems to be a pretty good deal, since it seems most shops stock them at about $44 dollars each, plus tax. I appreciate the info, that's really useful to know that the diameter is not negotiable, but the width can be varied.

Thanks again everyone!

I'd order a couple of spares as well. I live in an area where bicycling is popular and can't think of a single shop that stocks 27" tires. 700c and 26" are all over the place, but not the older 27" tire sizes. If you tear a tire in the middle of nowhere on a 4000mi trip, finding a 27" replacement could be a pain in the neck!

If it were me, I'd want to be touring on a bike with either 700c or 26" wheels...


Can I ask, why the preference of those two sizes? It seems to me that 27" is right in the middle of those. What's the deal with 700c tires/wheels anyway? What makes them superior? It's just a slight size difference correct? Or is there something else about the 700c wheels that make them better for touring?

1st. Good choice of tires - they should serve you well.
2nd. If you hang around the bike industry awhile, you'll find they change "standards" every few years. The glass-half-full folks believe this is because equipment and technology is ever improving and the change reflects this.

The glass-half-empty (and it's cracked, too) crowd will tell you it's to keep us sheeple buying latest and greatest stuff to pad the bank accounts of the cynical rich.

I say don't worry about why - buy what you like and let the chips fall where they may.

Can I ask, why the preference of those two sizes? It seems to me that 27" is right in the middle of those. What's the deal with 700c tires/wheels anyway? What makes them superior? It's just a slight size difference correct? Or is there something else about the 700c wheels that make them better for touring?

I can't say for sure, but in the USA, 27" was once more popular, particularly with everyday bikes. But as European (or European-ish) racing bikes became more popular, the 700C wheels that they use took hold and displaced the 27", even outside of racing bikes. As you probably suspect, there's no functional difference between the two. You should check out Sheldon Brown's tire-size tables (http://sheldonbrown.com/tire-sizing.html).

There are a lot of nearly identical wheel sizes out there, mostly because the USA, UK, and France (and probably other countries) all had their own systems, which are now mashed together.

One bit of info that's missing from this thread: 27" or 700c are measures of the rim diameter that a particular tire will fit on. Hold on, I want to quibble a little here. 27" and 700c are strictly nominal designations that should not be treated as measurements. In theory the 27" tire --or a 27" wheel with tire installed and inflated to pressure-- has an outside diameter of 27" (depending, of course, on the exact tire used etc). Aside from that, they are designation according to different systems; the 700c designation comes from the metric-based French system, while 27" is an English-based English system. To make them compatible, 700c is sometimes called 28," which only adds to the confusion since the 28" rim is actually smaller than the 27" rim.

Anyway, just quibbling. I have no quibble with the rest of your post:

The 23/25mm or 1 1/8" measurement indicates how fat around the tire is. So a 700x23 and a 700x35 will fit on the same rim, but the 35mm tire might be too fat to fit in the frame. And any 27" tire will fit on your current rim, whether 7/8", 1 1/8" or 1 1/4" wide.

Truman's advice on where to find 27" tires is good. Or you could rush order from an online bike shop like Nashbar or Performance.

700c is actually 622mm, which is a measurement. A large difference between 27" and 622 rims is that 27" rims are straight-sided and 622 are hooked rims. Hooked rims hold the tire on better. Old tires can blow off 27" rims - had it happen. There is definitely a functional difference.

The biggest difference is that tire technology, not engines, is the major advance in automobiles, and it's the same in bikes. You can get more advanced tire technology in 622 (700c) than you can in 27". Whether you're into wide comfort tires or narrow racing tires, you can get better tires in 700c than in 27", in terms of comfort, handling, grip, and rolling resistance. Of course we can argue all day about what "better" means, but just look at the variety available in each of those types.

700c is actually 622mm, which is a measurement. A large difference between 27" and 622 rims is that 27" rims are straight-sided and 622 are hooked rims. Hooked rims hold the tire on better. Old tires can blow off 27" rims - had it happen. There is definitely a functional difference.

The biggest difference is that tire technology, not engines, is the major advance in automobiles, and it's the same in bikes. You can get more advanced tire technology in 622 (700c) than you can in 27". Whether you're into wide comfort tires or narrow racing tires, you can get better tires in 700c than in 27", in terms of comfort, handling, grip, and rolling resistance. Of course we can argue all day about what "better" means, but just look at the variety available in each of those types.

Not quite. If you measure across a 700c rim bead seats, you will get 622 mm. If you do the same for a 27 inch rim, you will get 630 mm. Both 700 and 27 inch are approximate, really just labels. That four millimeter difference in radius is why 700 and 27 are not interchangeable. The other numbers, 23 mm, 25 mm, 28 mm, 1 1/4 " et cetera are the width of the tire when inflated. The mounted and pressurized diameter of the overall wheel is what it is, not exactly predictable by tables or equations. The width does provide an indication of tire air volume.

Old 27 inch rims did not have hooked beads, and can only be safe with something like 80 psi or less. Some modern 27's have hooked beads, and the Gatorskins and Paselas can be used on them all the way up to their max inflation levels, around 120 psi. If you do not have hooked beads, you should get the widest Gators you can for your rim, so that the added air volume can make up for using a lower air pressure.

700c is actually 622mm, which is a measurement. A large difference between 27" and 622 rims is that 27" rims are straight-sided and 622 are hooked rims. Hooked rims hold the tire on better. Old tires can blow off 27" rims - had it happen. There is definitely a functional difference.

The biggest difference is that tire technology, not engines, is the major advance in automobiles, and it's the same in bikes. You can get more advanced tire technology in 622 (700c) than you can in 27". Whether you're into wide comfort tires or narrow racing tires, you can get better tires in 700c than in 27", in terms of comfort, handling, grip, and rolling resistance. Of course we can argue all day about what "better" means, but just look at the variety available in each of those types.

youre wrong about hooked 27's. I have some: Araya super-hard anodized hooked rims. Theyre even deep-section aero rims too... tre modern for 1982.

the major functional difference between 700c and 27" is how hard it is to find tires. Since you now have two new tires, your 27 inchers are every bit as good as 700c for your 4k ride.

have fun.

One bit of info that's missing from this thread: 27" or 700c are measures of the rim diameter that a particular tire will fit on. The 23/25mm or 1 1/8" measurement indicates how fat around the tire is. So a 700x23 and a 700x35 will fit on the same rim, but the 35mm tire might be too fat to fit in the frame. And any 27" tire will fit on your current rim, whether 7/8", 1 1/8" or 1 1/4" wide.

Truman's advice on where to find 27" tires is good. Or you could rush order from an online bike shop like Nashbar or Performance.

+1 on 27" x 1 1/4". Nashbar and Performance both carry them. Look like there are several Performance stores in the Chicago Area
Selection of 27" tires seems to have improved lately with really nice Continentals and Panaracer models avaiable

You can convert to 700c and get a very slightly larger tire in the same space and a greater selection. (You need to move the brake pads down 4 mm, about 1/4 inch)
700x35 will fit that frame even with fenders (but there can be the scraping sound if the tire pick up gravel)

Can I ask, why the preference of those two sizes?

If you read my post, I think you'll understand why I prefer readily available 700c or 26" tires to hard to find 27" tires...

youre wrong about hooked 27's. I have some: Araya super-hard anodized hooked rims. Theyre even deep-section aero rims too... tre modern for 1982.

the major functional difference between 700c and 27" is how hard it is to find tires. Since you now have two new tires, your 27 inchers are every bit as good as 700c for your 4k ride.

have fun.Yeah, you're right. I rode straight-sided 27" rims in the 60s and 70s and wasn't aware that some manufacturers had later made 27" hooked rims. The OP's Matrix ISO Tech tires look like they had a bead designed for hooked rims. One should only run wire bead tires on non-hooked rims. I see that the 27" Gators only come in wire bead, so all good anyway. PITA to tour with wire bead, though, because of the spare problem.

If you read my post, I think you'll understand why I prefer readily available 700c or 26" tires to hard to find 27" tires...

Right, I read your post. Availability. But I thought there might have been some other reason that you preferred them pertaining to their function or efficiency, lifetime, whatever.