# Bike tire sizes??



## joshman108 (Apr 10, 2011)

I mtb. But i found an old road bike the other day. It has 27x1 1/8 tires on it. But all the tires i find online are like 700 x something. Can someone explain these 700 things? Will they fit a 27 inch wheel? Ive never seen these sizes in the mtb world so i could use alittle help. 


Also, I found a 27x1 1/4 online. Will this adequately fit a 27x1 1/8?

Thank you!


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## andulong (Nov 23, 2006)

27" is the old standard 700 c is the new standard. The tires are not interchangeable but the tubes are. A 700 c tire is about 1/4 " shorter than a 27. The tires you mention should work fine but wait for a few more opinions. Rim width is the real deciding factor. And just because they will fit the rim does not automaticlly mean that they will work with the brakes and frame clearance wise.


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## Kerry Irons (Feb 25, 2002)

*Sheldon Brown*



joshman108 said:


> I mtb. But i found an old road bike the other day. It has 27x1 1/8 tires on it. But all the tires i find online are like 700 x something. Can someone explain these 700 things? Will they fit a 27 inch wheel? Ive never seen these sizes in the mtb world so i could use alittle help.
> 
> Also, I found a 27x1 1/4 online. Will this adequately fit a 27x1 1/8?


Everything you need to know about tire sizes: http://www.sheldonbrown.com/tire-sizing.html Read and learn, grasshopper.


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## joshman108 (Apr 10, 2011)

so is a 700 bigger or smaller than a 27 inch?


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## PJ352 (Dec 5, 2007)

joshman108 said:


> so is a 700 bigger or smaller than a 27 inch?


A 700c tire fits on a 622c rim, while a 27 inch tires fits on a 630c rim, so the 700c is smaller.


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## andulong (Nov 23, 2006)

By bigger do you mean does it fit a larger diameter rim or is it wider or is it heavier or does it have a taller profile? In my first reply I told you that a 700 is slightly shorter (diameter) than a 27" and if you look at the link provided it will tell you more than you ever need to know about tire sizing. If this is what you are looking for...a 700 tire fits on a smaller diameter rim than a 27 " tire does. No, they will not fit the same rim, they may be the same width or have the same profile (distance from bead to high point of tread. If you are looking for 27 inch tires there are still some available out there but your choices are limited. If you decide to swap for a new set of 700c wheels or rebuild with 700c rims then you will most likely have compatiability issues with your brakes.


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## PJ352 (Dec 5, 2007)

andulong said:


> If you decide to swap for a new set of 700c wheels or rebuild with 700c rims then you will most likely have compatiability issues with your brakes.


Literally true, but because the difference that matters measures from axle to rim (4mm's) it's usually workable. 

The bigger problems with old bikes are usually drivetrain/ freewheel issues.


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## kykr13 (Apr 12, 2008)

joshman108 said:


> so is a 700 bigger or smaller than a 27 inch?


I'm going to guess that you might be looking at upgrades. If so, this probably doesn't make a lot of financial sense. Nothing wrong with 27" wheels but not every LBS will have tires for them in stock (nashbar.com will, however).


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## AndrwSwitch (May 28, 2009)

There are a few nice tires available for 27" wheels, but for the sake of future-proofing, I've generally replaced damaged 27" wheels with 700C wheels on 27"-wheeled bikes I've owned.

The brakes thing is sometimes an issue, sometimes not. On my current commuter, for example, I still have a 27" front wheel, but there's just enough range left on the brake arms to substitute a 700C. Brakes are not a hugely expensive part to replace, but if it takes you a little time to earn $60 (it does for me,) you don't want to go blindly swapping them around. Buying the right brake for an older bike is a huge PITA - the mounting bolts are different.

1-1/8" is a largish tire for a road bike. The same tire in a 700C model is typically marketed as 28mm. Someone who knows the inches-to-millimeters conversion will no doubt mention the discrepancy. If you read the Sheldon article linked above, you'll know that these sizes are not entirely accurate. 1-1/4" is big enough that clearance on a modern bike can be a real issue, although I think most 27"-wheeled bikes still had generous enough clearance that you'd get away with it, especially if it has 1-1/8" tires to begin with.

Are the current tires actually damaged, or just ugly? Unless the sidewall is actually bulging somewhere when you inflate them, or there's exposed tube or exposed bead, the tire is probably fine - cracked or blistered rubber doesn't really matter, IME. The brake pads, on the other hand, have a fairly short shelf life and should be replaced if they're more than a couple years old.

In general, I think it's not worth upgrading bikes of the age and pricepoint to have 27" wheels. Of course there are a few exceptional bikes kicking around, and if something is actually damaged, judicious replacement with more modern parts can make a big difference in terms of longevity.


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## joshman108 (Apr 10, 2011)

andulong said:


> By bigger do you mean does it fit a larger diameter rim or is it wider or is it heavier or does it have a taller profile? In my first reply I told you that a 700 is slightly shorter (diameter) than a 27" and if you look at the link provided it will tell you more than you ever need to know about tire sizing. If this is what you are looking for...a 700 tire fits on a smaller diameter rim than a 27 " tire does. No, they will not fit the same rim, they may be the same width or have the same profile (distance from bead to high point of tread. If you are looking for 27 inch tires there are still some available out there but your choices are limited. If you decide to swap for a new set of 700c wheels or rebuild with 700c rims then you will most likely have compatiability issues with your brakes.


Yes I meant wheel diameter. sorry i didnt even see that in your first post!

This explains alot, thanks guys! And as for WHY im replacing them, its a funny story. I was gonna replace them cuz the sidewalls are dry/cracked/old/ugly/ and i just wanted new ones for the sake of it. But then when I went to replace the tubes i couldnt even get the tires off. In the end I had to use bolt cutters to cut through the tires (turns out they had metal rods in them) just to get to the tubes...which was weird.

But as for the 1-1/8 size.... i think it might be wrong, as sheldon said, because I put them up to my 1.95 mtb tires and they are literally half as wide. So the "size" may not even be accurate.


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## andulong (Nov 23, 2006)

joshman108 said:


> I had to use bolt cutters to cut through the tires (turns out they had metal rods in them) just to get to the tubes...which was weird.


Those "metal rods" are there for a good reason. They are called beads. Without them the tire would not stay on the rim. Some tires have folding beads that are made out of some other tough material (kevlar or similar) You might want to check out Performance Bike for some inexpensive 27" tires.


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## andulong (Nov 23, 2006)

27 inch tires on sale at Performance Bike. If you have a store nearby you can walk in and ask for the online price...no shipping.

http://www.performancebike.com/bikes/Product_10052_10551_1089785_-1_1590008_20000_400235

They appear to be available only in the 1.25" size though. Maybe what you looked at before.


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## JCavilia (Sep 12, 2005)

joshman108 said:


> But as for the 1-1/8 size.... i think it might be wrong, as sheldon said, because I put them up to my 1.95 mtb tires and they are literally half as wide. So the "size" may not even be accurate.


Sizes vary from marked size sometimes. Unless the frame/fork/brake clearances were very tight with the old tires, you can almost certainly fit 27x1/4. It's the most readily available 27" size now. Smaller ones can be found, but they tend to be more expensive. Those Performance tires aren't bad for the price.

BTW, you probably didn't need to cut the beads to get the tires off. Coming from MTB, where tire removal is easy because the large tire size gives you a lot of slack, you probably don't have the knack for road tires yet. They have to be tighter to stay on with the narrow size and high pressure, so there's some trick to removing and installing them.

What kind of bike is this? If you know make/model/age (approximate) people here may be able to give you more specific advice.


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## kykr13 (Apr 12, 2008)

andulong said:


> Those "metal rods" are there for a good reason. They are called beads. Without them the tire would not stay on the rim. Some tires have folding beads that are made out of some other tough material (kevlar or similar) You might want to check out Performance Bike for some inexpensive 27" tires.


Yup. You'll see tires listed as wire bead (metal rods) or as folding or kevlar bead. Wire bead tires hold their shape so in that respect they're a little easier to change (IMO) but sometimes they're a tight fit depending on the specific tire and rim. Some are a bear to change but they will work. Folding weigh a little less and cost a little more.

And you shouldn't have to cut a tire off the rim - ever. Good, heavy duty levers (Pedro's for example) will make it easier. And they're sold in packs of 3 since they do break once in awhile...


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## joshman108 (Apr 10, 2011)

JCavilia said:


> BTW, you probably didn't need to cut the beads to get the tires off. Coming from MTB, where tire removal is easy because the large tire size gives you a lot of slack, you probably don't have the knack for road tires yet. They have to be tighter to stay on with the narrow size and high pressure, so there's some trick to removing and installing them.
> 
> What kind of bike is this? If you know make/model/age (approximate) people here may be able to give you more specific advice.


Ill be darned. I guess I just dont have the knack, but dang it sure seemed impossible to me, even with tire levers. :mad2: Oh well. 

It was a terranaught arial. I think its around 20-30 years old. 

Ya ill have to watch vids on how to take them off. I could use a lesson.
thanks again.


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## joshman108 (Apr 10, 2011)

haha ya i watched this
http://www.youtube.com/watch?v=i5K-DXt9djA
and it was definitely not that easy to take off. I think the age of the tire was the kicker. 
But note to self: dont use boltcutters. Got it.


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