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-   -   Newbe Question? Is 28 smaller than 27? (https://www.bikeforums.net/bicycle-mechanics/421890-newbe-question-28-smaller-than-27-a.html)

Tony N. 05-24-08 04:15 PM

Newbe Question? Is 28 smaller than 27?
 
Sorry for this but I did search and am more confused. I purchased a Paver Mongoose and noticed it has 28x1.75's on it but don't see a lot of tires that size for sale. Some of the research I've done here indicates that it is a 700c. If so what not call it that? Also if a 27 is bigger than a 700 then if you change a 27 out for a 700 then the brade pads must be lowered which is true so then I surmise that it is smaller so how can a 28 be smaller than a 27?
Thanks,
Tony

Joshua A.C. New 05-24-08 04:17 PM


Originally Posted by Tony N. (Post 6754096)
Sorry for this but I did search and am more confused. I purchased a Paver Mongoose and noticed it has 28x1.75's on it but don't see a lot of tires that size for sale. Some of the research I've done here indicates that it is a 700c. If so what not call it that? Also if a 27 is bigger than a 700 then if you change a 27 out for a 700 then the brade pads must be lowered which is true so then I surmise that it is smaller so how can a 28 be smaller than a 27?
Thanks,
Tony

It probably says "29". Mysteriously, 700c wheels, on a mountain bike, are called 29s.

CaptainCool 05-24-08 04:23 PM

http://www.sheldonbrown.com/tire-sizing.html


28 x decimal 622 mm Some German tire companies use this non-standard designation for 622 mm ("700c") tires.

DieselDan 05-24-08 05:38 PM

Kenda is notorious for doing this.

HillRider 05-24-08 05:49 PM

The "29" refers to approximate outside diameter of the complete wheel and tire combination. For that matter "27" and "700" originally did too. 29 MTB wheels are just fat tires on 700c diameter rims.

These days, rim dimensions have been standardized under the ETRTO/ISO definitions. Now 27" rims are ETRTO/ISO 630 (i.e. 630 mm bead seat diameter) and 700c rims are ETRTO/ISO 622. So going from 27" rims to 700c rims requires lowering the brake pads 4 mm or half of the 8 mm diameter difference.

Tony N. 05-24-08 07:56 PM

OK so is 28 actually smaller than 27 or if a tire has 700 on the sidewall, is it a 27?

HillRider 05-24-08 08:06 PM


Originally Posted by Tony N. (Post 6755057)
OK so is 28 actually smaller than 27 or if a tire has 700 on the sidewall, is it a 27?

First unless you are dealing with VERY old English bikes, there are NO 28" size bike tires. They are called 29 and use 700c rims with fat tires.

If a tire says 700c it is NOT a 27, it is a 700c. 27" bike tires are different from 700c tires and fit a very slightly larger rim. As above 27" rims are 630 mm diameter and 700c are 622 mm.

DieselDan 05-24-08 09:24 PM

Lemme clarify, Kenda colabels their 700c hybrid tires as 28".

cudak888 05-24-08 10:09 PM


Originally Posted by Tony N. (Post 6755057)
OK so is 28 actually smaller than 27 or if a tire has 700 on the sidewall, is it a 27?

EDIT: Your Mongoose Paver uses 700C tires, a.k.a. 622mm, and sometimes known as a 28" tire when the 28 is followed with a fractional size.

You can't answer any of those questions due to their extreme generality. First read the Sheldon Brown page linked above (or if you want the utterly, most comprehensive chart of virtually every wheel size to exist, http://www.bikecult.com/works/wheelsizes.html), then read the markings on your tires and rims.

Once you're clear as to what you have, re-phrase your question so that there is no doubt as to what you wish to do to X size tire on Y size rim. As it is now, your three tire sizes can be interpreted as follows:

There are multiple sizes - diameter wise - that are known as 28". Most commonly termed 28" tire is the 28x1-1/2, a.k.a. 700B. 635mm in diameter, designed for English roadsters. It is unlikely that you have this rim or tire. The second tire to be commonly badged - today - is the 700C tire, as DieselDan indicates. 700C is also known as 622mm, or 28x(a certain fractional size).

Generally, 27" as known today is always considered 630mm in diameter regardless of the tire - the other two existing variants are unusual enough to be ignored in this case.

The "700" term can be applied to the virtually extinct 700A and 700D sizes, or the more common 700B (known better as a 28x1-1/2/635mm tire used on English roadsters), or the presently popular 700C size, which is technically 622mm.

P.S.: There is no such thing as a 28x1.75. Either a 26x1.75 or a 28x(fractional size).

-Kurt

HillRider 05-25-08 07:22 AM


Originally Posted by DieselDan (Post 6755533)
Lemme clarify, Kenda colabels their 700c hybrid tires as 28".

This is confusing and misleading Marketing jargon. I presume they call them "28" because the tires aren't as fat as true MTB tires so the outside diameter of the tire is about 28".

Tony N. 05-26-08 09:07 AM

Thanks everyone. I'VE GOT IT!!!!!! Sorry for shouting. :-) I sometimes get excited when the old light bulb comes on. It don't take me long to get it like maybe 6-12 times and usually I'm going to get it or not. This tire is marked 28x1.75 AND 700x45C. Why so confusing. I'm still old school and used to be and still is I guess with a cruiser when you got a 26" bike, it had 26" wheels. You didn't guess whether it was tire or wheel size or maybe sometimes one way and sometimes the other. Riding is so much more fun.
Thanks again for bearing with me.
Tony

n4zou 05-26-08 01:59 PM

Once I looked into ordering a 20' container of bicycles from China. The pictures portrayed nice looking touring bikes with rear and front low rider racks, third water bottle mount, spare spoke hooks (with spare spokes in them), adjustable stem, frame pump pegs and pump, bottle dynamo and lights, and trekking bars. All you needed was panniers and off you go. They were advertised as having 28" tires. I e-mailed several times asking about rim size as I did not want bicycles with odd size tires. I never managed to get the information I wanted and gave up. All I could every get from them was; Tires are 28" send payment via bank wire.

roca rule 06-02-08 06:41 PM

well i think they have a different kind of rims and brakes. www.eldiariomontanes.es/.../07/DMO-REG-068.html this is what i meant even the brakes are different instead of clamping the wheel they pull up because the rimm has no wall.

cudak888 06-03-08 09:10 AM


Originally Posted by roca rule (Post 6806801)
well i think they have a different kind of rims and brakes. www.eldiariomontanes.es/.../07/DMO-REG-068.html this is what i meant even the brakes are different instead of clamping the wheel they pull up because the rimm has no wall.

:twitchy: OP's question was already answered weeks ago, and it turned out he had 700C's, and not 28"s?

Why did you bump the two-year-old thread at C&V too about the same subject?

-Kurt


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