hueyhoolihan

#t=25

acidfast7

Just have them read the Schwalbe website as they list the French, German and ISO sizes next to each other

Marathon Plus - Schwalbe Fahrradreifen, Rollstuhlreifen, Scooter- und Mopedreifen

TransitBiker

Just putting this out there, that there are different size 700 standards, but 700c and 29 are the same size.

- Andy

dynaryder

Tire Sizing Systems


Agreed. See the second paragraph in the above quote. 2"+ 700c tires should be the only tires designated 29er,everything else is just marketing hype. When I bought my '08 Novato,it was between that and the Muirwoods 29'r. The Muirwoods was called a 29er,but came with either 40s or 42s and would def not fit 2" knobbies.

Rootman

Wouldn't it be wonderful if they just got rid of the marketing hype and stuck to designations that made sense?

A guy I know was frustrated that the bike shop would not sell him tubes for his 29" tires, they were "only made for 700c's" was their excuse. When I explained that 29" and 700c were the same thing and he just needed to make sure the stem and width range were right he got mad and stormed off to the BS to "give them what for". So the ignorance is everywhere.

So generally 29" tires refers to older bikes using the imperial measurement or to newer bikes with wider tires, but not always! Just match the stem type and width and you should be good.

acidfast7

Or just always read the ISO sizing.

I've never seen a tube, tire, rim or wheel that didn't have it clearly marked.

modelmartin

So what do the inch designations refer to anyway? 700 mm is about 27 1/2 inches. Does it refer to the OD of the tire? OD of the flange of the rim and the 700mm is the diameter of the bead?

Antique car tires (early 30s and older)are sized by OD. Modern car tires are sized by rim diameter.

Anyone have the knowledge?

alan s 

The 29" designation refers to the outside diameter of a 700c tire that is about 29" (xx-622). The 622 is the rim size. The xx number (width) will be relatively large 60mm+ for a 29" tire. 26" Big Apples in 60-559 (aka 26" x 2.35") have about a 27.5" outside diameter. It's all a little confusing, unfortunately.

Ultimately, you need to match the tire to the rim and to the frame and fork. Also, you need to match the inside diameter of the rim to the tire width. If the tire is too wide for the rim, the rim will fail or the tire will feel squirmy, and if the tire is too narrow for the rim, the tire will not seat properly.

herzogone

As alan s referenced earlier (and just elaborated on), details can be found at https://sheldonbrown.com/tire-sizing.html. To summarize, 700C was from French sizing, originally based on the nominal diameter in mm, including a specific size tire (C was a width designation, there were also A, B, and D). It also notes that 29" is just a marketing term for some wide 700C tires (mostly MTB, presumably based on the approximate outsize diameter of the tire). As most have mentioned, ISO is the most clear, it consists of two numbers, the inner rim width in mm, and the bead seat diameter of the rim. When in doubt, check ISO size.

modelmartin

You missed the point. Is the inch designation such as in a 27 X 1 1/4 refer to the O.D of the tire or the diameter of the bead? I know all about the ISO sizes. My query was more historical in nature.

herzogone

Sorry for the misunderstanding, the linked article answers this in much detail. Basically, the general answer to your question is, yes, the inch sizing (as well as the older metric sizing) was historically based on the outside tire diameter, not bead diameter or any part of rim size.

devianb

My 700c wheels are 19mm wide where as my "29er" wheels are 25mm wide, otherwise same diameter without tires mounted.

ragnar.jensen 

And my "29er" wheels are 19mm wide...
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Ragnar

I-Like-To-Bike

My 622mm wheel rims are marked as 19mm wide on one bike and 21mm on the other. Both have 47-622mm Marathon tires mounted.

TransitBiker

Would a 700c wheel fit on a 26 inch wheeled bike?

- Andy

tjspiel

If there is enough clearance, then yes. Rim brakes would be a problem though as they probably wouldn't line up.

There's also 650B which falls in between and is gaining some popularity on off road bikes. Used to the see 650c on Tri bikes.

Some people will put 650B wheels on a standard road bike as a way to get additional clearance for wider tires, but you will also need to replace the brake calipers.

alan s 

700x35 and 26x2.35 fit on my Surly Troll with full fenders and racks f/r. Could go with even larger tires (or much smaller), with disc brakes and plenty of clearance, of course.

dynaryder

Depends on the frame/fork. My Bad Boy Ultras were designed to swap between 700c and 26" to go from street riding to off road. Just for fun I put a set of 700's on my old 1x1 and they fit just fine.

TransitBiker

So the catch is the rim brakes would need to be taken off for the taller wheels, and some other braking setup employed??

I'm going to have to do some research on this, because i'd love to put 700c wheels on my uptown. I think it'd give me better high end ratio speed without doing much to the low end. Catch is, i can't use discs on this frame, and the hubs are what they are....

- Andy

ragnar.jensen 

There are adapters to move the brake bosses. I think the most known were Mavic's (no longer made.)



Alternatives are still made and sold though:
Xtracycle 26" to 700c Brake Post Conversion Adapter | Bike Trailer
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Ragnar

dynaryder

The brakes have to be moved. There were some caliper brakes back when they started the transition from 27" to 700c that had enough up/down adjustment for the pads that you could just tweak them,but most modern brakes won't do this. Also,you have to check that the frame/fork have the height clearance for taller wheels. My 1x1 was designed to take really wide tires,so 26x2.3"(what were on it when I bought it) and 700x42(those 700's in the pic) fit no prob. But while my BBU's can handle 26x2.1" knobbies,700x28's are close,and most 32's won't fit under the fork.

Nope,going from 26" to 700c will raise your gearing across the board. Plug in your numbers and see:
Sheldon Brown's Bicycle Gear Calculator

The thing about IGH's is you can only raise or lower the entire gear range. On a derailleur bike,swapping an 11-28 cassette for an 11-34 will lower your granny gear but leave the high untouched. Swapping your big ring for a bigger one will do the opposite. But you can't change the gears inside a hub,you can only swap the rings and cogs to move the range up or down.

wolfchild

It depends on how much room there is in the frame and fork...My Surly 1x1 has a lot of room and I can easily fit 700x42 tires and full fenders...My other MTB can only fit 700x32 plus full fenders. Both bikes have disc brakes so switching wheels is not a problem.

TransitBiker

Thanks for all the replies & info.

Sadly i looked today, and there is definitely not enough room. The whole thing is set up for 26 inch wheels. I would need a new fork with proper spacing, and the rear rack mounts (not moveable) only give enough clearance for the fender.

Happily, though, i can say that my plan to put a fatter tire on the back is still possible. New wheels are definitely still a go once i get the money together, but they are gonna have to be 26 inchers.

- Andy