Re: [CR]TA Cranks, threads, etc.

(Example: Racing:Beryl Burton)

From: "jerrymoos" <jerrymoos@sbcglobal.net>
To: "Mark Petry" <mpetry@bainbridgeisland.net>, <classicrendezvous@bikelist.org>
References: <00f801c344d7$7cc74f40$7f00000a@SKIDROW>
Subject: Re: [CR]TA Cranks, threads, etc.
Date: Mon, 7 Jul 2003 19:40:00 -0500


Mark, the pedals are fairly well documented. The latest TA road pedal are marked as BSC, but there is a note with TA letterhead in each box stating (in French) that the pedals are metric thread, but will fit either metric or ISO cranks. The TA cranks I just received were not in an original box, so I don't know if TA are enclosing any notes explaining the crank threading.

Regards,

Jerry Moos
Houston, TX


----- Original Message -----
From: Mark Petry
To: classicrendezvous@bikelist.org
Sent: Monday, July 07, 2003 5:31 PM
Subject: [CR]TA Cranks, threads, etc.



>
> In re the current discussion on pedals threading in "hard" or easy, here
> is my thought. The thread forms used for ISO standard vs. old style BSC
> / italian / french threading for FREEWHEELS had some differences not
> only in the diameter and pitch of the threads, but also the the thread
> forms and the finishing of the thread crowns and valleys.
>
> Memory has faded (anybody else have this problem) but seems to me the
> Italian hubs had 55 degree threads, and the french threads were radiused
> in the crowns and grooves (others were flat). Current ISO standards
> dictate a 60 deg thread andgle and the crowns and grooves finished with
> a flat. An italian freewheel, if you recall, would fit on a BSC hub
> with a "class B fit" that required some lubrication and more than normal
> torque, because the diameter and TIP were the same, but the thread forms
> slightly different.
>
> Is is possible that the TA pedal spindles, even tho threaded to an ISO
> standard 9/16 X 20 size, may have slightly different thread forms "from
> the old style" and therefore cause slight interference (but no shavings)
> when threaded into "modern" crankarms.
>
> =====================================================
> Mark Petry 206.618.9642
> Beautiful Bainbridge Island, WA
> mpetry@bainbridgeisland.net
>
> =====================================================
> "Never be afraid to try something new. The Ark
> was designed by amateurs. The Titanic was
> designed by professionals."
>
> R. Buckminister Fuller
> =====================================================