# What"s the difference ?



## gonegonzo (Jan 18, 2006)

I've always heard of it but never did know the difference between "Narrow Window" and "Wide Gap" TYCO armatures .

What is the advantage and disadvantage of each ? 

How do you tell them apart ?

Thx ,
Gonzo


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## Rich Dumas (Sep 3, 2008)

I did a Google search on Tyco wide gap armatures and came across one of my posts from a few years ago. Quote:
I saw a discussion of this issue many years ago on an HO BB, my memory is a little hazy, but if I recall correctly we are talking about factory Tyco armatures that had narrow stacks. With narrow stacks the gap between the poles is wider than normal. These arms are hard to come by, so in most cases it would not be legal to race them. The obvious question is why did Tyco sell some cars with these armatures? My best guess is that it was not done on purpose. Whoever was cranking out the armature blanks made an unauthorized change or just screwed up. Maybe nobody noticed the difference or they didn't want to dump the off spec blanks, so they got wound and ended up in some of the cars. Wide gap armatures are reputed to have more torque than regular armatures.

There were a few other posts in the same thread:

The switch between wide and narrow gap was a deliberate design change. Most HO motors are made by Mabuchi. The design was changed for reasons unknown (better camera motor?) and Tyco went along with the change. 
The same is true with the soldered vs "welded" coms and the skewed stack design.

Just speaking on gap, not diameter, leg width, etc there was a .055" which is the current style with Tyco and Tomy that some consider "narrow" gap. .088" which is the old style Tyco, the Aurora G+ at .105" and some unique ones I ran across which I called "Big Gap" at .125" and "Grand Canyon" at a whopping .155".


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## slotking (May 27, 2008)

with inline racing, the wide gaps seemed to out perform the narrow gap arms.

you have 2 issues at play here.
1>less metal = lighter arm
2>electrical field is different due to 1.

because the the common arm became both narrow gap and crimped tabs, both soldiered tabs and wide gap arms both were deemed not legal in many groups.

you can still buy them from slottech.net


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## slotcardan (Jun 9, 2012)

......


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## gonegonzo (Jan 18, 2006)

This is a lot to absorb but I'm trying .

Thx ,
Gonzo


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## slotking (May 27, 2008)

feel free to ask
again, slottech sells them if you want 1 or more


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