RE: [CR]stripped pedal threading

(Example: Events:Cirque du Cyclisme:2007)

From: "Steve Birmingham" <sbirmingham@mindspring.com>
To: <classicrendezvous@bikelist.org>
Subject: RE: [CR]stripped pedal threading
Date: Tue, 8 Nov 2005 00:18:37 -0500
In-Reply-To: <MONKEYFOODasSmz6UuE00005637@monkeyfood.nt.phred.org>


Baird wrote " Not a major operation, but you do need to be careful to get the tap straight."

I've found it's easy to keep the tap straight, if I start from the backside of the crank. The tap has some good threads to start in, and the rest goes quite easily. Piloted taps help as well.

Steve Birmingham Lowell, Ma

Date: Mon, 7 Nov 2005 20:06:48 -0500 From: bjwebel@mac.com To: Matteo Brandi <cheroketz@libero.it> Subject: Re: [CR]stripped pedal threading Message: 14

On Nov 7, 2005, at 7:44 PM, Matteo Brandi wrote:
> Hello
>
> is there any tool/way,to "fix" damaged threading on the pedals hole?
>
>
> Thanx
>
> Matteo Brandi Firenze Italy

Yes, it depends on how damaged the threads are.

If the threads are not too damaged, like when a pedal unscrews and then comes off at the end, taking some threads with, you may be able to run a tap through the crank to clean out the threads an allow you to put a pedal in. Not a major operation, but you do need to be careful to get the tap straight. From: http://www.sheldonbrown.com/ tooltips/taps.html

"How and Where Do You Use Taps and Dies on a Bicycle?

Taps and dies are used only occasionally in routine bicycle repair, but they have some specialized applications that can be very handy.

Older bicycle mechanics remember when almost every new European bike needed its pedal threads cleaned out with a tap before the pedals could be installed. Chrome plating fouled up the threads' dimensional tolerances, and it fell on the mechanic's shoulders to fix the problem. Today's aluminum cranksets and better manufacturing techniques have solved the problem, and the main use for pedal taps is to convert French-threaded cranks to the more commonly available English pedal thread size (9/16 x 20). Any work on pedal threads re quires special taps, sold through bicycle tool sources, because you need a left-hand thread tap for the left crank. "

If it is very damaged, you can put a "helicoil" into the pedal hole, that completely replaces the threads. This is more involved, but I don't think it is that difficult for a competent mechanic. I've never had occasion to do it.

Baird