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New Mclaren for the African poor
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adam2
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Joined: 02 Jul 2007
Posts: 6206
Location: North Somerset

PostPosted: Fri Sep 09, 2016 12:09 pm    Post subject: Reply with quote

I was thinking not just of ground clearance.
Larger wheels perform better on very rough surfaces. As an example, consider two large stones or small boulders spaced say 40cm apart. A small wheel will drop into the gap between the stones with a shock and then be pulled out again by the forward momentum of the vehicle.
A larger wheel will effect bridge the gap and allow the vehicle to proceed relatively smoothly.

As an extreme but illustrative example, note that a car may be driven with care on gravel, but a skateboard with small wheels can not proceed.
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vtsnowedin



Joined: 07 Jan 2011
Posts: 4264
Location: New England ,Chelsea Vermont

PostPosted: Fri Sep 09, 2016 12:37 pm    Post subject: Reply with quote

adam2 wrote:
I was thinking not just of ground clearance.
Larger wheels perform better on very rough surfaces. As an example, consider two large stones or small boulders spaced say 40cm apart. A small wheel will drop into the gap between the stones with a shock and then be pulled out again by the forward momentum of the vehicle.
A larger wheel will effect bridge the gap and allow the vehicle to proceed relatively smoothly.

As an extreme but illustrative example, note that a car may be driven with care on gravel, but a skateboard with small wheels can not proceed.

You have a point there. I live five miles from the nearest pavement and the town dirt road turns to hub deep mud in the spring thaw. Not the place for any corvettes or any other low sling small wheeled car during that period.
The old Volkswagen Beatles had very tall and narrow tires compared to other vehicles of the day. With the engine right atop of the rear drive wheels they were excellent in snow and with chains on were unstoppable.
As far a rough terrain crossing goes it is a combination of frame height and wheel base. A short jeep like vehicle will go over much rougher ground then a long truck with the same tires and axle pumpkins. One of the best off roaders we have ever had were a couple of Geo Trackers made by a Japanese firm for GM. We used to take it out on snow machine trails in summer and on skidder trails in the woods that have three foot water bars across them.
Back to fix ability. I prefer something so well made it seldom if ever breaks to something that needs regular repairs even if they are easy to do. Every time you break into an engine or transmission you risk introducing dirt or other contaminants and any false step with the reassembly is a chance for you the amateur mechanic to ruin your vehicle. Bolt on accessorizes like alternators and power steering pumps are fine but anything between the oil pan gasket and the valve cover gasket I want to leave alone as long as possible.
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Catweazle



Joined: 17 Feb 2008
Posts: 2189
Location: Little England, over the hills

PostPosted: Sat Sep 10, 2016 10:09 pm    Post subject: Reply with quote

Larger wheels or higher profile tyres shift the axle and differential case further off the ground. This makes a big difference if trying to drive on a rutted road.
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cubes



Joined: 10 Jun 2008
Posts: 565
Location: Norfolk

PostPosted: Sat Sep 10, 2016 11:47 pm    Post subject: Reply with quote

woodburner wrote:
vtsnowedin wrote:
I'll stick to my Nissan Frontier thank you.
http://www.edmunds.com/nissan/frontier/2013/


$18000+, ostentatious, unfixable without high tec workshop, demands specific spares.

Ox

don't know price, basic, fixable with suitable hammer, spares can be made locally in many cases.

You keep your Frontier, I'll take the Ox.


http://www.thisismoney.co.uk/money/cars/article-3776023/Meet-OX-World-s-flatpack-vehicle-built-12-hours.html

Cost is apparently 10-15k
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vtsnowedin



Joined: 07 Jan 2011
Posts: 4264
Location: New England ,Chelsea Vermont

PostPosted: Sun Sep 11, 2016 12:20 am    Post subject: Reply with quote

Catweazle wrote:
Larger wheels or higher profile tyres shift the axle and differential case further off the ground. This makes a big difference if trying to drive on a rutted road.

Also a skilled driver will run the wheels on the high spots and not straddle stumps and rocks sticking up in the middle of the trail that want to hang up the differentials. To get real clearance improvement you have to go to a Hummer style suspension. Jacked up 4x4 pickup trucks still have two differentials that only moved up as much as the oversized tires have moved the axle centers up. A few inches at best. They have gained on the problem of high centering on the frame of the pickup when topping a sharp rise or obstruction but if they come up hard on one of the differentials they will need locking rear ends to pull themselves back off or a winch.
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vtsnowedin



Joined: 07 Jan 2011
Posts: 4264
Location: New England ,Chelsea Vermont

PostPosted: Sun Sep 11, 2016 12:29 am    Post subject: Reply with quote

woodburner wrote:
vtsnowedin wrote:
I'll stick to my Nissan Frontier thank you.
http://www.edmunds.com/nissan/frontier/2013/


$18000+, ostentatious, unfixable without high tec workshop, demands specific spares.

Ox

don't know price, basic, fixable with suitable hammer, spares can be made locally in many cases.

You keep your Frontier, I'll take the Ox.

Oh I fully intend to keep my Frontier. How much are you going to invest in the Ox company venture?
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Catweazle



Joined: 17 Feb 2008
Posts: 2189
Location: Little England, over the hills

PostPosted: Sun Sep 11, 2016 8:26 am    Post subject: Reply with quote

vtsnowedin wrote:
Also a skilled driver will run the wheels on the high spots and not straddle stumps and rocks sticking up in the middle of the trail that want to hang up the differentials. To get real clearance improvement you have to go to a Hummer style suspension. Jacked up 4x4 pickup trucks still have two differentials that only moved up as much as the oversized tires have moved the axle centers up. A few inches at best. They have gained on the problem of high centering on the frame of the pickup when topping a sharp rise or obstruction but if they come up hard on one of the differentials they will need locking rear ends to pull themselves back off or a winch.


You can't always avoid the ruts - they form where the trail is pinched, between trees, rocks, next to ponds etc.. When the trail is really slippery the drag from axles and diffs is often enough to stop you, even a couple of inches makes a big difference.

Geared hubs move the axles much higher, but initial cost and economy is a problem for utility vehicles. Independent suspension is perhaps more viable, although less rugged than solid axles.
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vtsnowedin



Joined: 07 Jan 2011
Posts: 4264
Location: New England ,Chelsea Vermont

PostPosted: Sun Sep 11, 2016 12:28 pm    Post subject: Reply with quote

Catweazle wrote:
vtsnowedin wrote:
Also a skilled driver will run the wheels on the high spots and not straddle stumps and rocks sticking up in the middle of the trail that want to hang up the differentials. To get real clearance improvement you have to go to a Hummer style suspension. Jacked up 4x4 pickup trucks still have two differentials that only moved up as much as the oversized tires have moved the axle centers up. A few inches at best. They have gained on the problem of high centering on the frame of the pickup when topping a sharp rise or obstruction but if they come up hard on one of the differentials they will need locking rear ends to pull themselves back off or a winch.


You can't always avoid the ruts - they form where the trail is pinched, between trees, rocks, next to ponds etc.. When the trail is really slippery the drag from axles and diffs is often enough to stop you, even a couple of inches makes a big difference.

Geared hubs move the axles much higher, but initial cost and economy is a problem for utility vehicles. Independent suspension is perhaps more viable, although less rugged than solid axles.

All true of course. The smaller rigs like a tracker being narrower can usually crowd one side and get the opposite side wheels up on the edge of the rut made by bigger vehicles.
https://www.carsforsale.com/geo-tracker-for-sale-C137362
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Catweazle



Joined: 17 Feb 2008
Posts: 2189
Location: Little England, over the hills

PostPosted: Sun Sep 11, 2016 9:51 pm    Post subject: Reply with quote

vtsnowedin wrote:
All true of course. The smaller rigs like a tracker being narrower can usually crowd one side and get the opposite side wheels up on the edge of the rut made by bigger vehicles.
https://www.carsforsale.com/geo-tracker-for-sale-C137362


Over here that's the Suzuki Vitara, quite a useful car, very popular at off-road fun events.
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BritDownUnder



Joined: 21 Sep 2011
Posts: 238
Location: Hunter Valley, NSW, Australia

PostPosted: Sun Sep 11, 2016 10:02 pm    Post subject: Reply with quote

Tell you what, those US used vehicle prices are quite reasonable.

in Australia people still want serious money for a high mileage clapped out 4WD. Ten or Twenty thousand for a ten year old toyota is considered the norm. Not sure about the Vitara but i did buy a suzuki recently but not vitara.

No rust problems over here of course.
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vtsnowedin



Joined: 07 Jan 2011
Posts: 4264
Location: New England ,Chelsea Vermont

PostPosted: Mon Sep 12, 2016 9:17 am    Post subject: Reply with quote

The most popular vehicle in Vermont is a Chevy Silverado pickup with 22,000 of them registered last year, followed by the Subaru Legacy with 18,000.
When you lump all models together by brand Toyota comes out on top 59.000 to Subaru at 54,200
Out of 575,214 vehicles registered in Vermont just 225 were all electric last year.
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