Trouser

im rebuilding a old 10 speed and didnt even think of looking at wheel size bought a parts bike that had 26 inch wheels then relized that the original bike had 27s. my question is what can i do to get brakes for the frame that came with 27s to fit the 26s?

Standalone 

don't think you're going to have any success with that. 27" and 700c wheels can be interchanegable, but I've never heard of 26" working.

JiveTurkey

27" wheels have a radius of 315 mm and 26" wheels are 279.5 mm. That means the brake pads would have to sit 35.5 mm or about 1 3/8" lower, which is a lot. I'm guessing the frame and fork take a caliper-style brake. There are some long-reach caliper brakes, but don't know if they'll reach down that far.

I'd try to sell the wheels you have and look for a 27" wheelset.

fietsbob

Braze on cantilevers... But

BB drop may be too much, put it too low.. 630 to 622, IE 27 t0 700C
is more realistic , thats only 4mm reduction ..

650B is trendy now .. 584, thats 19mm. may also be too much..

dabac

You can always try home-made drop bolts .
Strange name really. Drop tabs, or drop plates would have seemed more natural.

powitte

I think you might have success with 650Bs and long reach calipers. A manufacturer will state exactly how long is their long reach, so it should just be math.

I think the bottom bracket height may not be a huge deal, depending on the frame. Usually 'racy' sort of bikes have a higher bottom bracket (with the stock wheels) to allow you to pedal through corners. So, smaller tires would cause it to drop a bit, but that may make it just handle more like a touring bike, and you may have to be cautious on tight turns.

As another up side, 650Bs would allow you to run wider tires, if that's a benefit to you.

tcs

There are eight different, non-interchangeable “26 inch” wheel sizes.

1) 26 x 1.25: bead seat diameter 599mm. Obsolete.
2) 26 x 1 1/4: bead seat diameter 597mm. Schwinn S6. Obsolete. Still made for very old Schwinn lightweights, but uncommon.
3) 26 x 1 3/8: bead seat diameter 590mm. Traditional “English racer” size, and used on American-built single- and three-speeds and inexpensive bike boom 10-speeds. Also known as 650A and EA.3. Obsolete for new bicycles in the USA, but very widely available in bike shops, hardware stores and big boxes. Common in Japan where it is used on new bicycles, and common legacy size in the UK. This is also a common wheelchair tire size.
4) 26 x ?: bead seat diameter 587mm. Also known as 700D. Very obscure and obsolete size.
5) 26 x 1 1/2: bead seat diameter 584mm. Also known as 650B. Obsolete, but a few companies are trying to revive this size for both road and mountain bikes with proprietary tires they provide.
6) 26 x 1 3/4: bead seat diameter 571mm. Also known as 650C and Schwinn S7. Obsolete. In the USA these wide tires were used on old Schwinn middleweights. Tires are still made, but uncommon.
7) 26 x 1: bead seat diameter 571mm. Known as 650C as well (!), this narrow racing format is based on an obsolete Italian sew-up tire rim size. Used today on time trial and triathlon bikes.
8) 26 x 1.0 to 2.35: bead seat diameter 559mm. The ubiquitous mountain bike tire size, descended from the American balloon tires of over a half century ago. Now made in a huge array of widths and tread patterns. Widely available worldwide in widths of ~1.75 inches and greater; the narrower sizes are available in well-stocked bike shops. In the wheelchair world, this smallest 26-inch size is sometimes referred to as “25-inch”.

ironwood

I disagree with your characterization of the 650B-584 wheel size as obsolete.A number of companies such as Rivendell, Velo-Orange, Velocity, Panasonic, Schwalbe and Soma, among others have revived the size, and are providing frames, rims, and tires. Many older road bikes from the eighties have been converted to 650B.

One of the advantages of the size is that it allows you to run larger witdth tires, eg. 38mm, with fenders on frames that otherwise accept only 32mm wide tires. The wide tires are much more comfortable.

I converted a Univega to 650B, and ride it every day. There is an olld thread on the C&V forum devoted to 650B conversions.

Sixty Fiver

A conversion from a 630 wheel to a 559 wheel will be very difficult... very few things are impossible if you own a torch.

Better to find a 700c wheel set as a replacement as then very little will change with the bike's geometry and most brakes will adjust for a small reduction in rim size... you will also expand your selection for tyres with the common 700c road wheel.

Going the other way... bikes with 650 A wheels can often be converted to 650 B or 700c (590 - 584 or 622) although fenders and brakes will probably need to be changed.

garage sale GT

It's probably a 590mm 26x1-3/8 if it looked like a 27.

Things can be done but it would cost more and be a lot more trouble than finding a genuine 27.

a new 27" rear wheel probably runs around $35 so spending too much cash and worry swapping in the 26s isn't worth it, especially if the 26 bike is saleable.

DannoXYZ 

Heck, you can buy an entire bike with 27" wheels at garage-sales or thrift-stores for $20-40. Many of them go at local campus-police auction for $10-20. I got a crappy-looking MTB with top-of-the-line (at the time) Deore-XT for $40. Just a little overhaul and waxing and it was good as new! Sometimes, it's not worth your time and money to try impossible projects when a comparable solution can be found for next to nothing.

thook

I did this for an old friend of mine. He had a mid 70's Dawes Galaxy, but he liked the cush of the fatter 26" mtn bike tires. Well, he couldn't run anything wider than 1.75 because of the chainstay spacing, but working with he had I managed to take some chromed/steel sidepulls......LeeChi, or something....off a cheap Huffy mtn bike. I had to grind the slots for the pads a bit, but they reached. Awful lotta flex, but he didn't care.

Oh, and the BB height was definitely tricky. But, again.......he didn't care.

cs1

Truthfully 650B is kind of cool. But it really doesn't fit a need other than being different. Rims and tires will never be as plentiful or cheap as 26" or 700C. Nor will the selection be as plentiful. With that said I wouldn't mind doing a 650B conversion myself. But not with the goal of making a current bike better. All 650B would do is satisfy my need to create something different.

ironwood

On a smaller frame, 23' or less 650B wheels allow for wider tire and fenders. I'm not sure my bike is "better", but it is more versitile with the wider tires, that is I can handle more dirt and broken pavement, and can go more places But then I got along perfectly well for many years without them.

RaleighComp

I did this semi-successfully once. I found a weird department store quality "mountain" bike on the side of the road with a broken cottered crankset in the mid-90's. It had these weird centerpull mechanical brakes with no arch wire. It looked as if some manufacturer developed these brakes specifically to convert excess road frames to "mountain" bikes. 26" tires, flattish bars with more rise than what was typical and thumb shifters. 18 speed (6 speed freewheel) IIRC. I took all the components off the old frame and used most of them to successfully make a "mountain" bike out of an early 70's step-through (girl's) blue Raleigh Grand Prix that had been my wife's childhood bike. Everything went together alright and I used it to ride on the beach when we lived in Hampton, NH. The only problem was that the BB was now significantly lower and it was pretty easy to strike the pedal on the ground in a moderate turn. I eventually switched the bike back to 27" wheels to reclaim the pedal clearance but I left the upright bars and thumb shifters on. It's a pretty comfy grocery getter.

garage sale GT

I just want to point out in order to be extra clear that many old bikes called 26" CANNOT take mountain bike size tires because the rim is the wrong diameter, whether or not the frame is wide enough. The rim will be too big to stretch the tire around.

thook

Indeed......I'm (personally) aware of that, but I just assumed that Trouser was referring to mtn bike sizing and not 3pd or something. As well, with mtn bike wheels or 3pd, the axle width is different.

I don't suggest anyone spread or squeeze the frame to fit, either, unless they don't care about the paint. Or, if the brake bridge manages to seperate. Yeah......that happened. I was an old bike, but it's fixed.

Redhatter

Did the bike have rim brakes or disc brakes? I suspect disc brakes might work, but if the frame doesn't suit them then you're out of luck.

CliffordK

There are two diameters that are important (along with width).

• The bead seat diameter is important for determining the brake caliper size.
• And the outer diameter of the tire determines the height, and how it fits in the frame.
  (Plus, of course, width which may be important for frame clearance)

The idea of the old 26" sizes was that all the different tire sizes ended up being about 26".

https://en.wikipedia.org/?title=Bicycle_wheel


Your 27" tire will be about 27" OD.,
A 700c X 23 or 25mm tire will be about 26.5" OD.

So, fitting in the fork or rear brake bridge, the 26" tire will be about 1/2" shorter than the 27" tire, and drop the BB down by about 1/2".

You'll probably be ok on the cornering with the BB assuming the original frame isn't overly short.

As far as long reach calipers... The very early MTBs (1982-ish), mostly had brake calipers designed to fit around the balloon tires. If you can find them, they might have adequate reach and size. I'm sure there are other long reach calipers available, depending, of course, on which rim you're using.

Of course, fat tires are now being installed on 650b and 700c rims.

Retro Grouch 

This is the smart answer. Everything else is just throwing good money after bad.

acostanut

Vintage weinmann long reach brake calipers work. I know because that is exactly what I did. I converted a 27 inch 10 speed into a 26 1/38eighth wheel convertion. No problem with crank clearance.

bulldog1935

650b is here to stay, and as noted above, this is your best chance for making a conversion to smaller wheels (other than 700c)

If you can find the 650a English wheels, Grand Bois has a good tire selection.
A lot of people with old English 26" bikes have discovered these to their joy.

The only way to use ISO-559 would be to have canti studs brazed to the frame and fork

cny-bikeman

Get another parts bike or set of 27" or 700c wheels. It's a much better solution.

Jeff Wills

Please note that this thread was started 5 years ago.

CliffordK

It takes time for the perfect bike build out of mismatched parts