Forum | Marketplace | Knowledge Base | | H1 site | H2 site | H3 site
Click Here To Visit H-Line Conversions
Click Here To Visit H-Line Conversions
Click Here To Visit Spartan Offroad
Click Here To Visit Spartan Offroad
Click here for a listing of all HUMMER Network sponsors

Hummer Knowledge Base

The Hummer Knowledge Base

Running Gear/Differentials/Torque:


Subject: HML: Re: diffs
Date sent: Wed, 28 May 1997 14:43:19 PDT

I find it easier to think in terms of torque instead of power when talking about diffs. What we care about is the torque going to each side. The short explaination...

An open diff always distributes torque equally left to right. If one wheel has very little traction, little torque gets applied to that side. Hence, you get little torque to the traction side.

A limited slip wants rotational speed to be equal. However, with little load on them, they function only on preload. They can allow a little more torque to go to one side but usually only about 50-100% more. With a no traction wheel, 100% of little is still little. Of course you can have a "built" LS that changes the ratio...

The Torsen allows a torque split of around 4:1. Hence, the traction side can receive 4x the torque going to the slipping side.

BTM works by adding resistance to the system. By adding brake drag to the slipping side, you increase the torque going to that side. Hence, torque to the other side (traction) also increases. Since an open diff splits torque equally, BTM is of marginal benefit. It does work in a very limited sense but only because the open diff is not ideal. Don't count on it.

With a LS (like the factory Trac-Lock on the Jeep), BTM works better because the device is adding resistance to the low traction side already.

BTM works well with the Torsen because it allows a much higher torque biasing. A little brake drag on the low traction side translates into 4x torque to the traction wheel. With geared hubs, this is 8x torque...more than enough for most situations.

As Hal points out, the theory behind BTM has been around before Torsens and before Hummers. It does work on open diffs and LS units..you just have to use light brake pressure. BTM just works really well with the Torsen + geared hub design.

Gerald


Back to main page

The Hummer Knowledge Base is a collection of informative posts from the Hummer Network forums and mailing lists, contributed material and links to outside web sites.
The Hummer Network is not responsible for the accuracy of the information contained herein or on outside web sites, nor for any situation arising from the use thereof.
2006-2011 by The Hummer Network. No material from the Hummer Knowledge Base may be reprinted or republished in any form without permission.