700 wheels onto bike which takes 27"

i wonder what needs to be done for it to work since 27 (686mm) and 700
are very close

best
w

Cheapest way to solve this problem is with some old Mafac or Diacompe
centerpulls--total cost, probably $25, including the cable hangers
you'll have to add. You'll need to make sure your levers work adequately
with that setup, tho.

Cheers
Colin Murphy

If he has short reach brakes then a set of normal-reach calipers
would probably make it work. Shimano and Tektro models are both
readily available. Hard to guess what's on the bike now since
105 could not have been original equipment in 1983.

--Paul

Try Alfred E. bike - http://aebike.com/ They have Tektro
side-pull road calipers in 47-57mm for $11.99 each, and
53-71mm, and 61-78mm for $9.99 each. Or you could look
around for some Tektro dual pivot long reach calipers - they
were about $32 a pair last time I saw them advertised

The Shimano BR-A550 and BR-R600 dual pivots are nice, but a
lot more expensive

You need to compare rim diameters, not the arbitrary traditonal size
numbers. "27 inch" rims are 630 mm, while "700c" rims are 622 mm. That
8 mm diameter difference translates into a 4 mm difference in radius.

Thus, to install 700c wheels in place of 27s, you need to _lower_ the
brake shoes by 4 mm.

What would today be called "short reach" brakes were very uncommon in
the days of 27 inch wheels.

Talking about "normal-reach" is highly counterproductive, since
"normality" changes with fashion. The normal reach brakes seen on most
bikes today have a reach range of 39-49 mm. The brakes you're thinking
of are more in the 47-57 range, and older bikes made for centerpulls
often require something longer than that, even for 27 inch wheels.

Sheldon "Numbers, Not Adjectives" Brown
+-------------------------------------------------+
| One measurement is worth 50 expert opinions |
| --Howard Sutherland |
+-------------------------------------------------+
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

this seemed to be a commonly asked question i just didn't know how to
search

thanks
w

Cheers

Colin Murphy"

Egads, do they still MAKE these brakes? Where would you get them?
Without breaking into some bicycle museum?

Even Third Hand/Loose Screws doesn't have a set that I know of...!

May you have the wind at your back.
And a really low gear for the hills!
Chris

Chris'Z Corner
"The Website for the Common Bicyclist":
http://www.geocities.com/czcorner

Brake reach is the only question. Older, "standard reach" brakes work
best. Older Campy sidepulls might work, with a bit of tweaking. Sheldon
Brown sells "drop bolt" adapters for the rear -- usually the front fits,
but the rear has a bit too much for the newer brakes.

--

David L. Johnson

__o | Arguing with an engineer is like mud wrestling with a pig... You
_`\(,_ | soon find out the pig likes it!
(_)/ (_) |

Anyone have any experience with these tektro super-long calipers? I'm
planning on upgrading my current cheaper-'n-sh** centerpull, and these
are the ones that fit my budget best with the necessary reach.

however, i cant help but wonder- they are decidedly un-graceful
compared to 'normal' brakesets, made for BMX perhaps? are they stiff?
dependable? this would be the one brake on a fixie that sees a LOT of
traffic.

anthony

Even cheaper is to keep an eye out on trash day. I frequently see
70's era low-mid range road bikes in the trash with either Weimann 730
or Mafac centerpulls. Dissassemble, clean, lube, use some Kool Stop
salmon brake shoes and modern cables (see Sheldon Brown's nice article
on cable installation at http://www.sheldonbrown.com/cables.html ) and
you'll have adequate brakes even with the longer reach.

Bill "waste not, want not" Putnam

>
> Egads, do they still MAKE [Mafac/Diacompe centerpulls]? Where would you get them?

Well, Chicago has two great resources for old stuff like this: a store
called Urban Bikes with a whole annex full of sorted and categorized
parts dating back probably fifty years, and an ongoing recycled bike
sale called Working Bikes (http://workingbikes.org/sales.htm), both of
which are great sources for this kind of thing, and cheeep. So I'm
probably spoiled with the ease of finding old fitting parts.

Colin

They are not stiff. They are, in my experience, dependably awful.

There are only two kinds of long reach (60mm+) sidepull brakes I've
ever been able to get sorta-halfway-decent braking out of (with good
pads and a lot of fiddling around):

- Dia Compe Big Dog dual-pivot (out of production a long time)
- ACS Boa w/10mm center bolt (requires drilling out the fork crown)

Furthermore, these brakes usually need a high-ratio lever (like an old
4-finger MTB lever or a motocross lever) to get them to work right.
They might do OK with drop bar levers, but I've not tried that yet.

BMX brakes are, after all, designed for coming to a stop after the
sprint race is over. No big hurry there. Racers aren't even
_allowed_ to have one on the front.

If you need stopping power, long reach, and 6mm center-bolt mounting,
the best solution is a U-brake or V-brake adapter plate like one of
these:

http://harriscyclery.net/site/page.cfm?PageID=49&Category=319

Both of these examples have arms that can be strapped to the stays or
fork legs with hose clamps, usually included. The resulting
arrangement is heavy and ugly as a mud fence, but works quite well.

A tidier but slightly less powerful fix is to use the venerable
Odyssey Pitbull bolt-mounted rollercam brake. Its integral cable
hanger can be removed in order to use a stem- or frame-mounted housing
stop (which is often more rigid):

http://shop.store.yahoo.com/penncyclebuy/odpitll.html

Chalo Colina