Simplex Automatic for Dummies

[DustyGold]

Why were these marketed as an "automatic?" Do they have more than one speed or "gear" compared to the earlier versions? I haven't ever seen a shift handle or the like on any servi-cycle, not like a Cushman Eagle. What makes my seri-cycle different from an earlier non-automatic? Thanks for any input.

[Ricks]

The very first Servi-Cycles did not use any transmission.  To stop, you shut off the motor.  In 1940, the shifter models came out.  These used a foot shift, that moved the transmission pulley in or out to change the gear ratio.

In 1953, Simplex introduced the Automatic, which, as the name implies, was completely Automatic.  The transmission pulley used weights to move the sheaves in and out to adjust the ratio of the drive.They work exactly like a Torque Convertor on a modern go kart.

[DustyGold]

These used a foot shift, that moved the transmission pulley in or out to change the gear ratio.

Is this a lot like the belt driven pulley system on a 1910 Harley Davidson? It looks like the lever (shifter) on the 1910 is just tightening up the leather belt so to bike will move under more power.

[ndian22]

No that's a straight pulley setup on the HD, single ratio, which is engaged by the hand lever to go & released to idle. The Simplex is variable ratio that assist starts with low gearing and gradually increases to higher ratios required for increased speed. Similar to the operation of CVT drives as Rick mentioned in his post. No need to release the pulley to idle the mechanism does it all...thus the term automatic.

Rick C.

[DustyGold]

Similar to the operation of CVT drives as Rick mentioned in his post. No need to release the pulley to idle the mechanism does it all...thus the term automatic.

Rick C.

Well this post was a real eye opener to me. I went over to YouTube & typed in CVT. I didn't have any idea that's how the pulley system on my Simplex Automatic worked, or how a cars's automatic transmission worked. I thought each "pulley" on the bike was just a regular old pulley like on the front of an old V8 engine basically.