Appreciating the pedaling efficiency of Rigida 27x1" clincher rims and
tires I fabricated some adapter brackets to mount on my low-end
mountain bike frame originally set up with direct-pull cantilever
brakes. Conversion is made by removing the 26" mountain bike wheels
and brakes from their mounting posts. By installing the horseshoe
style adapters on the existing mounting posts the brakes can be
remounted on secondary posts located higher up the adapters. Simply
install 27" road wheels with HP tire sizes up to 1 1/8" having similar
index shifting gearing geometry and readjust the brakes. Naturally,
700C rims with similar tires will have even more clearance from the
frame.
CONS are 1) having excessive brake cable housing from the "raised"
brake post height and 2) increased bike leaning when utilizing the
welded-on kick-stand with the larger diameter road wheels.
I would attach photos if I knew how.
This setup works great for my riding needs where one bike is desired
for efficiently riding around town for most of the year while still
accommodating mountain bike wheels for one week of mountain bike camp
each summer.
I'm wondering if there is a market/need for this kind of bracket?

On Mon, 23 Jan 2012 11:34:20 -0800 (PST), Gordon Babbitt
wrote:

Appreciating the pedaling efficiency of Rigida 27x1" clincher rims and
tires I fabricated some adapter brackets to mount on my low-end
mountain bike frame originally set up with direct-pull cantilever
brakes. Conversion is made by removing the 26" mountain bike wheels
and brakes from their mounting posts. By installing the horseshoe
style adapters on the existing mounting posts the brakes can be
remounted on secondary posts located higher up the adapters. Simply
install 27" road wheels with HP tire sizes up to 1 1/8" having similar
index shifting gearing geometry and readjust the brakes. Naturally,
700C rims with similar tires will have even more clearance from the
frame.
CONS are 1) having excessive brake cable housing from the "raised"
brake post height and 2) increased bike leaning when utilizing the
welded-on kick-stand with the larger diameter road wheels.
I would attach photos if I knew how.
This setup works great for my riding needs where one bike is desired
for efficiently riding around town for most of the year while still
accommodating mountain bike wheels for one week of mountain bike camp
each summer.
I'm wondering if there is a market/need for this kind of bracket?

To answer your question, I doubt that there is much market for an
adapter to use both 700C wheels and the normal 26" wheels on a MTB for
two reasons:

1. You can get 1.3" wide, high pressure, 26" tires that roll about as
well as the larger 700C 1-1/8" tires.

2. Generally bicycle people are divided into two groups - those who
just ride and leave any tinkering to their local bike shop; and those
who wouldn't think of letting the LBS near their darling. The first
group wouldn't understand the difference between 700C and 26" tires
and the second group probably would prefer to just buy another bike.

As for actual difference, I have an aluminum frame road bike with 700C
tires and a steel frame touring bike with 26 x 1.3" tires. The tourer
is heavier then the road bike, but even with that handicap it is still
only about 1 KPH slower over 100K; or 100 Miles for that matter.


--
John B.

On 1/23/2012 8:32 PM, John B. wrote:
On Mon, 23 Jan 2012 11:34:20 -0800 (PST), Gordon Babbitt
wrote:

Appreciating the pedaling efficiency of Rigida 27x1" clincher rims and
tires I fabricated some adapter brackets to mount on my low-end
mountain bike frame originally set up with direct-pull cantilever
brakes.
...
I'm wondering if there is a market/need for this kind of bracket?

Most wheel changes I have heard of is people with older 27x1-1/4" bikes
that they wanted to fit 700c wheels on.

....
1. You can get 1.3" wide, high pressure, 26" tires that roll about as
well as the larger 700C 1-1/8" tires.
....

--
John B.

I think Continental makes a 26"/559 tire that is 1-1/8" wide. At least,
they did. A few years back I looked around once for the narrowest tire
that would fit on a 559 rim, and that was it.

Most people who want to run different sizes of wheels on one bike just
get a frame that has disk brake bosses and that cures any brake-fit
issue. Fitting narrow tires to a MTB still introduces gearing problems,
however.

The gearing on a MTB is already higher compared to a road bicycle: the
biggest chainring on a cheaper road bike is probably a 52-tooth, and the
biggest chainring on a MTB is usually 48-tooth (if it is even that big).
And since bicycle tires are bias-ply only, they have a round
cross-section--so a narrower tire is also going to have a smaller outer
diameter, too.

So the MTB is already geared wrong for road riding--and then if you go
putting a skinny tire on it, the rear wheel gets smaller,,,,, and the
effective gearing gets even worse.

You can get some fat smooth-tread tires in MTB sizes that would perhaps
do better for longer riding, even though they feel heavier while
accelerating and climbing hills. The Maxxis Hookworms are listed as
being 2.5" wide, and the Schwalbe Big Apple tires come in a 2.3" width.

On Tue, 24 Jan 2012 13:32:13 -0600, DougC
wrote:

On 1/23/2012 8:32 PM, John B. wrote:
On Mon, 23 Jan 2012 11:34:20 -0800 (PST), Gordon Babbitt
wrote:

Appreciating the pedaling efficiency of Rigida 27x1" clincher rims and
tires I fabricated some adapter brackets to mount on my low-end
mountain bike frame originally set up with direct-pull cantilever
brakes.
...
I'm wondering if there is a market/need for this kind of bracket?

Most wheel changes I have heard of is people with older 27x1-1/4" bikes
that they wanted to fit 700c wheels on.

....
1. You can get 1.3" wide, high pressure, 26" tires that roll about as
well as the larger 700C 1-1/8" tires.
....

--
John B.

I think Continental makes a 26"/559 tire that is 1-1/8" wide. At least,
they did. A few years back I looked around once for the narrowest tire
that would fit on a 559 rim, and that was it.


I looked in the 2010 catalog and the narrowest I could locate was a 26
x 1.3". there was a 20" x 1-1/8th though.

Most people who want to run different sizes of wheels on one bike just
get a frame that has disk brake bosses and that cures any brake-fit
issue. Fitting narrow tires to a MTB still introduces gearing problems,
however.

The gearing on a MTB is already higher compared to a road bicycle: the
biggest chainring on a cheaper road bike is probably a 52-tooth, and the
biggest chainring on a MTB is usually 48-tooth (if it is even that big).
And since bicycle tires are bias-ply only, they have a round
cross-section--so a narrower tire is also going to have a smaller outer
diameter, too.

So the MTB is already geared wrong for road riding--and then if you go
putting a skinny tire on it, the rear wheel gets smaller,,,,, and the
effective gearing gets even worse.

That is not always true. I use mountain bike gearing on my touring
bike 44-32-22 with either a 11-34 or 12-32 cassette. works a treat if
you are in hilly country.

Another problem that the O.P. didn't mention is that the rear hub/axle
has a different spacing if changing between MTB and road wheels. It is
not insurmountable but does require a bit of tinkering.

You can get some fat smooth-tread tires in MTB sizes that would perhaps
do better for longer riding, even though they feel heavier while
accelerating and climbing hills. The Maxxis Hookworms are listed as
being 2.5" wide, and the Schwalbe Big Apple tires come in a 2.3" width.


--
John B.