650B conversion question

Frank Knox said:

I am updating a 48cm Schwinn Paramount P-15 which lacks clearance for
anything in the front. The front tire barely clears the caliper, but there
is plenty of fender clearance in the rear. Believe it or not, this bike was
sold this way when new in 1973!
I have purchased Honjo fenders for this bike.
Will rebuilding the front wheel with a 650B rim and tire solve this problem?

-snip-
Framebuilders have a specific wheel size in mind when
designing a frame. Changing that, or worse, changing half a
pair of wheels, can drastically change handling, often in
disconcerting ways ( such as limiting the ability to ride no
hands).
Sometimes that effect is moderate, sometimes severe.

My personal opinion is that this is a singularly bad idea.

My professional opinion is that you should borrow a 650B
wheel (and a $15 730 or 850 sidepull brake) and ride the
bike for a few long rides before committing to such a
modification.

If you decide not to change wheels you might consider
truncating the mudguard just behind the crown:
http://www.yellowjersey.org/photosfromthepast/AMKEST.JPG

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Frank Knox said:

I am updating a 48cm Schwinn Paramount P-15 which lacks clearance
for anything in the front. The front tire barely clears the
caliper, but there is plenty of fender clearance in the rear.
Believe it or not, this bike was sold this way when new in 1973! I
have purchased Honjo fenders for this bike.

This is a bike not even remotely designed for use with fenders.
Honjos, as far as I can tell from looking at the Jitensha Web site,
would need a fair amount of clearance between the tire and the
mounting hardware on the underside of the rim. You may not be able
to make this work even with 650B wheels.

You should consider trying 700C wheels, if it has 27" ones now- which
is likely given the vintage. You might get enough room for some SKS
(Esge) fenders. Frankly, though, my best advice is to save this bike
for a fair-weather gofast bike and to get a bike designed for fender
clearance.

Quoted message said:

Will rebuilding the front wheel with a 650B rim and tire solve this
problem?

I realize that I will need to replace the front calipers.

You should, if you haven't already, read the Rivendell Reader article
on this conversion. It gives the measurements that you need to make
to determine if this conversion can be done (not only is there the
diameter issue, but also the width needed between the chain stays and
fork blades).

Quoted message said:

How likely is it that handling will be affected if I only change the
front wheel?

It probably won't make the bike unrideable, but it will have the
effect of steepening the head tube by a degree or so and reducing
trail. This will make the bike less stable and may make the bike
unrideable hands-off. It'll also look darned weird with the big fat
front tire and the skinny rear tire.

Quoted message said:

If I decide to change both wheels, will this make pedal strike in
corners likely?

Not if you keep the inside pedal up. If you're not racing crits,
there's not much reason to pedal through corners.

"A Muzi" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Frank Knox said:

I am updating a 48cm Schwinn Paramount P-15 which lacks clearance for
anything in the front. The front tire barely clears the caliper, but

there

Quoted message said:

Quoted message said:

is plenty of fender clearance in the rear. Believe it or not, this bike

was

Quoted message said:

Quoted message said:

sold this way when new in 1973!
I have purchased Honjo fenders for this bike.
Will rebuilding the front wheel with a 650B rim and tire solve this

problem?

Quoted message said:

-snip-
Framebuilders have a specific wheel size in mind when
designing a frame. Changing that, or worse, changing half a
pair of wheels, can drastically change handling, often in
disconcerting ways ( such as limiting the ability to ride no
hands).
Sometimes that effect is moderate, sometimes severe.

My personal opinion is that this is a singularly bad idea.

My professional opinion is that you should borrow a 650B
wheel (and a $15 730 or 850 sidepull brake) and ride the
bike for a few long rides before committing to such a
modification.

If you decide not to change wheels you might consider
truncating the mudguard just behind the crown:
http://www.yellowjersey.org/photosfromthepast/AMKEST.JPG

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

I'm not sure much thought went into the design of this frame. It was a
custom 19" c-c P-15, (touring model), Paramount with Campy triple cranks,
braze-ons for racks, etc. and was delivered with sew-ups! I think the
Schwinn factory people just made it work with what they had on hand since
the size was less than their standard offering of the time.

What I think I'll try first is to install the fenders, substitute a pair of
700c wheels and see how much clearance is there.

Although the bike will be used only for on-road touring, I am concerned
about the possibility of front wheel lock-up with these metal fenders.

Frank Knox said:

Although the bike will be used only for on-road touring, I am
concerned about the possibility of front wheel lock-up with these
metal fenders.

Hmmm. You could bodge up some kind of safety release for the
attachment of the stays to the front dropout. Or you could attach the
stays midway up the fork legs, British style.

"Tim McNamara" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Frank Knox said:

Although the bike will be used only for on-road touring, I am
concerned about the possibility of front wheel lock-up with these
metal fenders.

Hmmm. You could bodge up some kind of safety release for the
attachment of the stays to the front dropout. Or you could attach the
stays midway up the fork legs, British style.

Thanks for the idea. I'll look about on the net for examples of this.

In article <[email hidden]>,

Frank Knox said:

"A Muzi" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Frank Knox wrote:

Quoted message said:

I'm not sure much thought went into the design of this frame. It was a
custom 19" c-c P-15, (touring model), Paramount with Campy triple cranks,
braze-ons for racks, etc. and was delivered with sew-ups! I think the
Schwinn factory people just made it work with what they had on hand since
the size was less than their standard offering of the time.

Quoted message said:

What I think I'll try first is to install the fenders, substitute a pair of
700c wheels and see how much clearance is there.

For a sufficiently determined modifier of fenders, almost any bike can
have enough clearance. If nothing else, SKS half-fenders should work.
Barring that, you can carve away most of the fender around the brakes,
or even build an interrupted fender that bolts ahead and behind the fork
and caliper.

Quoted message said:

Although the bike will be used only for on-road touring, I am concerned
about the possibility of front wheel lock-up with these metal fenders.

Instead of changing the wheel, what about changing the fork? It won't be
period-correct, but no more wrong than a 650B (!) wheel, and given the
price of high-clearance forks (in my experience, they go for about $10
in garage sale season, and come attached to an entirely superfluous
complete late-70s road bike of usable quality; cf. Mikado tourer,
Bianchi Sport, Motobecane, etc.)

I sometimes misunderstand this sort of thing, but note that racers in
Vancouver have to deal with low-clearance fender fitment as a matter of
routine for their Winter bikes. The solutions I suggested above are
among the most common ones. Right now the hot setup is the SKS
half-fenders, because they attach and remove quickly, but the downside
is they're not as good as normal fenders at keeping the rider and bike
dry and clean.

Unless the fender is physically being pinched by the brake (which you
fix by trimming it, sometimes quite severely), the only safety issue
should be making sure the back/bottom edge of the fender can't contact
the wheel.

--
Ryan Cousineau, [email hidden] http://www.wiredcola.com
Verus de parvis; verus de magnis.

Frank Knox said:

I am updating a 48cm Schwinn Paramount P-15 which lacks clearance for
anything in the front. The front tire barely clears the caliper, but there
is plenty of fender clearance in the rear. Believe it or not, this bike was
sold this way when new in 1973!
I have purchased Honjo fenders for this bike.

Will rebuilding the front wheel with a 650B rim and tire solve this problem?

It will solve _that_ problem, but will cause its own problems, as it
will lower the front of the bike.

Quoted message said:

I realize that I will need to replace the front calipers.

How likely is it that handling will be affected if I only change the front
wheel?

Pretty likely. It will also steepen the geometry and lower the
handlebars, likely causing the bike to become less comfortable.

Quoted message said:

If I decide to change both wheels, will this make pedal strike in corners
likely?

Maybe. A lot depends on the choice of pedals.

You might want to consider replacing the fork and front wheel with a
559 mm (26" mtb) one. This has surprisingly little effect on geometry,
because most MTB forks are "suspension corrected" with extra clearance
at the top so they can be interchanged with suspension forks.

I was running a 559 front wheel in a Rock Shox fork on my IRO fixed-gear
bike for a while, with 622 (700c) in back. Theres a photo at

http://sheldonbrown.org/iro

This replaced a rather tight fitting plastic fork that I found
unpleasantly harsh. It looked funny, but didn't present any handling
problems. I eventually reclaimed the Rock Shox fork for another project.

Quoted message said:

I'm not sure much thought went into the design of this frame. It was a
custom 19" c-c P-15, (touring model), Paramount with Campy triple

cranks,

Quoted message said:

braze-ons for racks, etc. and was delivered with sew-ups! I think the
Schwinn factory people just made it work with what they had on hand since
the size was less than their standard offering of the time.

When you look at "road" bikes under about 20" inches, especially back in
the days of the superstitious fixation on level top tubes, you'll find a
LOT of strange attempts to work around the fact that the wheels were
just too big for that size.

Keeping the fork blades short let them preserve a semi-reasonable length
of head tube and steerer.

Back in the day, touring bikes with clinchers were not uncommon.
Indeed, in the '70s, that's all my wife rode, because she was constantly
going back and forth between France and England and the USA. Tubulars
were the only tires that you could get in all three places. (Back then,
700c clinchers were just about unknown in English speaking countries,
and 630 (27 inch) stuff has never been easy to find in France.)

Sheldon "Gave Up On Tubulars After 3 Flats In 30 Miles" Brown
+----------------------------------------------+
| Check out my wife's tale of her experience |
| in the 1975 Paris-Brest-Paris at: |
| http://harrietfell.com/PBP1975.html |
+----------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Frank Knox said:

"Tim McNamara" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Frank Knox said:

Although the bike will be used only for on-road touring, I am
concerned about the possibility of front wheel lock-up with these
metal fenders.

Hmmm. You could bodge up some kind of safety release for the
attachment of the stays to the front dropout. Or you could attach the
stays midway up the fork legs, British style.

Thanks for the idea. I'll look about on the net for examples of this.

And, in fact, Frank did the conversion, it turned out great, and here's a
URL where you can see his work:
http://www.freewebs.com/650b/franksparamount.htm