Go Back   Horizons Unlimited - The HUBB > 4 wheels > 4WD Overland Tech

4WD Overland Tech GENERIC 4WD / 4 wheel TECH discussions and info that is valid for ALL brands. See brand specific forums.
Contact Overland Solutions for all your custom modifications and setup for overland travel.

Visit Matt Savage for VIAIR compressors, Air Lift Helper Springs, Tyre Levers, Chris Scott's Books & DVDs, KC Daylighters, Allisport Intercoolers, Overland Preparation and lots more!

Reply
 
LinkBack Thread Tools Display Modes
  #16  
Old 9 Nov 2005
Registered Users
Veteran HUBBer
 
Join Date: Sep 2002
Location: Nottingham, UK
Posts: 180
Hi Luke,

I haven't really decided what kind of vehicle to build on yet. Nyathi's outer dimensions were determined by the need (wish) to fit in a 6m shipping container. Relaistically, if I go bigger, a high-top container, or even an open-top container probably will be too small. So I have a blank sheet of paper to start with.

We want to be able to live inside, to give us the possibility of travelling in colder climes. (Nyathi was designed to live outside, as we wanted to be "camping", and we planned our route and timetable to make that possible and pleasant).

We also still want to be able to go anywhere that wheeled traffic can go, and be reasonably self-sufficient for a couple of weeks. I am leaning towards a 'Mog, but wary of the complexity. The slow speed is also unattractive, but we like to travel slowly anyway. Besides, a comparable vehicle could very rarely do even 100km more in a day than a slower Unimog.

My biggest fear of a compromise is ending up with a vehicle that has almost all the drawbacks of smaller campers, and almost all the costs and other problems of a big truck. I'll tell you what, you go first, and tell me how it worked out!? :-)

Back to the diff thing: I'll grant you that I didn't give much thought to the actual figures I used in my sums, but it's hard to work out what actually happens unless one quantifies the principles with some numbers. Now that I have thought it over, 2000Nm doesn't seem an unreasonable number to pull a 2000kg car up a gradient. (200Nm from the engine, and a 10:1 overall gear ratio in, say, 2nd gear?).

As you can see, I am not fully employed at the moment! :-)

Hi Peter: I wasn't aware that any Rovers made use of worm-type Torsen diffs(?) Or do you mean if you fit a Torsen as an after-market diff? Are you saying the use of ETC makes the performance of the Torsens worse, or that they are just terrible anyway?

(Of course LSDs and Torsens both make use of friction to slow the spinning wheel, but they do so by slowing the planetary gears, and not the shafts. That's why the friction clutches and worms don't present quite the same wearing-out problems as the brake pads in the case of a TCS. I'll leave it to a braver person than me to try and analyse a mixed ETC/Torsen scenario with some torque numbers!)

Cheers,

Michael...




[This message has been edited by SandyM (edited 11 November 2005).]
__________________
Michael & Sandy
http://www.expeditionoverland.com
Reply With Quote
  #17  
Old 10 Nov 2005
Gipper's Avatar
Contributing Member
Veteran HUBBer
 
Join Date: Mar 2004
Location: Banff,Canada/Poole,UK
Posts: 748
(QUOTE)

(In practice, TCSs tend to substitute independently progressive braking with a series of momentary "grabs" at a wheel. The frequency of these grabs does much the same thing as progressive braking, but a bit more sloppily. A system with independent braking pressures at each wheel would be hugely complex, I imagine. But the overall effect of the simpler system is very similar to what I described.)

Michael,
Sorry, thought you were talking about using LF Braking...
In this paragraph about braking - I see you were saying that in Theory, the TC should cut in in one progressive pulse. In Practice, if it did this the engine would stall before we can add throttle, thats why it has to pulse, so it slows the wheel even more progressively.


I understand the Diff Dynamics that the torque loss depends on the resistance level on the wheel, more wheelspin/less grip = less torque to both wheels, not just a single wheel.
What happens in Practice on the ground is the nice heavy hub, wheel and tyre on the end of the halfshaft have Momentum and this is why alot of the time when a wheel spins out (even in contact with the ground) the effect is total loss of resistance, it just keeps on spinning until the terrain changes enough to overcome the momentum - like a total lift off the ground.

I see what you mean with the extra power requirements theory, but again in practice, the fact that we are in low range with the CDL engaged - (lessening the power required) means there is plenty of torque there to overcome this.

Theres no doubt that the rear and front lockers are going to get you further in a straight line, but the TC system works a treat and has less potential to damage transmission it also means you can fight the wheel instead of having to constantly flick switches on and off.

When we are Teaching people to drive LR products, we still place the emphisis on ground reading and correct momentum, with the TC as something that will kick in if its needed.

Im just going for a spin on me bike, with its nice efficient chain drive and no diffs !!!
Cheers Guys
Grif
__________________
Cheers
Grif

'09 Suzuki DR650
'00 Discovery Series 2 V8
'95 Defender 90 300 Tdi Overlander
http://gipperstravels.blogspot.com/
Reply With Quote
  #18  
Old 10 Nov 2005
Registered Users
Veteran HUBBer
 
Join Date: Oct 2001
Location: France
Posts: 353
Torsen ‘worm’ type diffs have screw cogs for their planetaries. Initially they were incapable of dealing with really torquey engines and stripped regularly.
Detroit bought rights to the design and applied their metallurgy knowledge to it, creating the Detroit Trutrac (sp?) which is nicely toughened up.

I’m trying to work out the meaning of Peter’s “terrible” in large parts of the continent that’s come to mean good (the way “wicked” has been twisted in English)

“Live in” vehicles: A new thread perhaps?
Reply With Quote
  #19  
Old 11 Nov 2005
Registered Users
Veteran HUBBer
 
Join Date: Sep 2002
Location: Nottingham, UK
Posts: 180
Luke, I didn't know Detroit bought the torsen rights, but I have to say I have always been confused by all the various brand names and variations of each type of diff. I seem to remember the Easton(?), which was also a torsen type(?).

The torsen concept was very elegant - worm gears can drive, but they can't be driven. So by using them in the planetary system, the half-shafts can force the planetary gears to turn back and forth (as when cornering, the outer wheel speeds up and the inner slows down), but the crownwheel can't turn the planetary gears at all (which it would like to do when torque drops at one wheel, such as when traction is lost).

I can see why they would strip, though - if you open up a torsen, you can't help admiring the engineering feat required to fit all those carefully cut worm gears into a casing the size of a diff!

Grif, I am not really on a crusade against TC, though reading back what I wrote, it may seem like it! I stand by my observation about power sapping, even though most often it's not an issue because of low gearing. I have experienced it only once as a noticeable problem, when towing heavy trailers up steep (asphalt) mountain passes. Getting up the passes in dry weather, the TD5s needed low range 2nd and 3rd. When the asphalt got heavily rained on, the TD5s with ETC really struggled, even in low range 1st! And when we got to the top, I reckon the brakes had worked harder than if we had been going down the hill - they were extremely hot.

On the other hand, we only had one vehicle without ETC (and no axle lockers), and he couldn't make it to the top! So ETCis very effective, no question about that. It follows that whenever power is sapped by ETC, it is because wheels are spinning, and at that point, an otherwise-identical vehicle without ETC will be stuck.

Have fun on the bike, Grif - I assume you have given thought to converting it from 2x1 to 2x2???

Rgds,

Michael...
__________________
Michael & Sandy
http://www.expeditionoverland.com
Reply With Quote
  #20  
Old 11 Nov 2005
Registered Users
Veteran HUBBer
 
Join Date: Mar 2001
Location: Oslo, Norway
Posts: 142
Luke,

Thanks for the input. And yes, it's great fun with an expanding family. Never knew a baby could be this much fun actually!

------------------
Reply With Quote
  #21  
Old 14 Nov 2005
Registered Users
HUBB regular
 
Join Date: Apr 2003
Location: Vienna, Austria
Posts: 51
Hi Sandy, Hi Luke,

the aftermarket improved "Torsen" diffs are from Quaife (www.quaife.co.uk) - as the worm gears are parallel to the halfshaft-axis, there ist even more teething in contact and some friction plates deliver a base load.

Yes, seems someone taught me english dialect: The Quaife-equpipped Rovers with ETC are marvellous.

Regards,
Peter
Reply With Quote
  #22  
Old 14 Nov 2005
Registered Users
Veteran HUBBer
 
Join Date: Sep 2002
Location: Nottingham, UK
Posts: 180
Thanks for clearing up that misunderstanding, Peter. I have heard good things about the Quaife, although never actually used one or seen one in use, to my knowledge.

Rgds,

Michael...
__________________
Michael & Sandy
http://www.expeditionoverland.com
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 Registered Users and/or Members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


 
 
 

NEW! HU 2015 Motorcycle Adventure Travel Calendar is now available! Get your copy now for some terrific travel inspiration!

HUGE, 11.5 x 16.5 inches, beautifully printed in Germany on top quality stock! Photos are the winning images from over 600 entries in the 9th Annual HU Photo Contest!

Horizons Unlimited 2015 Motorcycle Adventure Travel Calendar.

"The calendar is magnificent!"

"I just wanted to say how much I'm loving the new, larger calendar!"

We share the profit with the winning photographers. YOU could be in the HU Calendar too - enter here!


HU DVD Autumn Special!

Take 40% off Road Heroes Part 1 until October 31 only!

Road Heroes features tales of adventure, joy and sheer terror by veteran travellers Peter and Kay Forwood (193 countries two-up on a Harley); Dr. Greg Frazier (5 times RTW); Tiffany Coates (RTW solo female); and Rene Cormier (University of Gravel Roads).

The first in an exciting new series, Road Heroes features tales of adventure, joy and sheer terror by veteran travellers."Inspiring and hilarious!"

"I loved watching this DVD!"

"Lots of amazing stories and even more amazing photographs, it's great fun and very inspirational."

"Wonderful entertainment!"

Check it out at the HU Store! Remember to use Coupon Code 'HEROES' on your order when you checkout.



Scottoiler automatic chain oilers. The most important accessory for your next motorcycle adventure!


Renedian Adventures


Renedian Adventures

What others say about HU...

"I just wanted to say thanks for doing this and sharing so much with the rest of us." Dave, USA

"Your website is a mecca of valuable information and the DVD series is informative, entertaining, and inspiring! The new look of the website is very impressive, updated and catchy. Thank you so very much!" Jennifer, Canada

"...Great site. Keep up the good work." Murray and Carmen, Australia

"We just finished a 7 month 22,000+ mile scouting trip from Alaska to the bottom of Chile and I can't tell you how many times we referred to your site for help. From how to adjust your valves, to where to stay in the back country of Peru. Horizons Unlimited was a key player in our success. Motorcycle enthusiasts from around the world are in debt to your services." Alaska Riders

contest pic

10th Annual HU Travellers Photo Contest is on now! This is an opportunity for YOU to show us your best photos and win prizes!

NEW! HU 2014 Adventure Travel T-shirts! are now available in several colors! Be the first kid on your block to have them! New lower prices on synths!

HU 2014 T-shirts now in!

Check out the new Gildan Performance cotton-feel t-shirt - 100% poly, feels like soft cotton!


What turns you on to motorcycle travel?


Global Rescue, WORLDwide evacuation services for EVERYONE

Global Rescue is the premier provider of medical, security and evacuation services worldwide and is the only company that will come to you, wherever you are, and evacuate you to your home hospital of choice. Additionally, Global Rescue places no restrictions on country of citizenship - all nationalities are eligible to sign-up!


New to Horizons Unlimited?

New to motorcycle travelling? New to the HU site? Confused? Too many options? It's really very simple - just 4 easy steps!

Horizons Unlimited was founded in 1997 by Grant and Susan Johnson following their journey around the world on a BMW R80 G/S motorcycle.

Susan and Grant Johnson Read more about Grant & Susan's story

Membership - help keep us going!

Horizons Unlimited is not a big multi-national company, just two people who love motorcycle travel and have grown what started as a hobby in 1997 into a full time job (usually 8-10 hours per day and 7 days a week) and a labour of love. To keep it going and a roof over our heads, we run events (22 this year!); we sell inspirational and informative DVDs; we have a few selected advertisers; and we make a small amount from memberships.

You don't have to be a Member to come to an HU meeting, access the website, the HUBB or to receive the e-zine. What you get for your membership contribution is our sincere gratitude, good karma and knowing that you're helping to keep the motorcycle travel dream alive. Contributing Members and Gold Members do get additional features on the HUBB. Here's a list of all the Member benefits on the HUBB.


Books & DVDs

amazon

All the best travel books and videos listed and often reviewed on HU's famous Books page. Check it out and get great travel books from all over the world.


Motorcycle Express for shipping and insurance!

Motorcycle Express

MC Air Shipping, (uncrated) USA / Canada / Europe and other areas. Be sure to say "Horizons Unlimited" to get your $25 discount on Shipping!
Insurance - see: For foreigners traveling in US and Canada and for Americans and Canadians traveling in other countries, then mail it to MC Express and get your HU $15 discount!




All times are GMT +1. The time now is 06:45.