NDCC Tire Design --> Obsolete and Unsafe? - Steel Soldiers::Military Vehicles Supersite

M1075 · 01-14-2007, 22:31

Found this on www.globalsecurity.org when looking for info on 5 tons...

The nondirectional cross country (NDCC) tire design on the M939 basic truck was engineered for cross-country applications prior to World War II. Changes in vehicle speeds, road construction, mission requirements, as well as advances in tire technology have made this NDCC bias tire obsolete and unsafe. This modification will change the tires from the current bias ply NDCC tire to a radial tire designed for on/off road. Recent improvement in radial tire design will provide better traction and mobility, which will enhance system safety.

maddawg308 · 01-14-2007, 22:46

I agree. The NDT and NDCC are great for offroad traction, and were top notch for their day. However, most know that modern tire tread designs provide better traction off road and on. They are not really unsafe off road, but on road they are far from safe at modern road speeds, mostly in wet conditions. The older tires just don't contact the ground much, they have a small "footprint". When you have to brake in wet conditions, the bigger the footprint, the better. NDTs and NDCCs will slide like all get out in wet conditions.

TheBuggyman · 01-14-2007, 23:22

Second that.
Sometimes the good 'ole days just were not that good, tire technology being one area of vast improvement.

JDToumanian · 01-15-2007, 02:55

Nothing about my 40-year-old deuce is safe 'by modern standards'... single-circuit braking, no shoulder belts, no impact energy absorption features or, perhaps most importantly, no rollover protection. But I like it just the way it is!... If Bill Gates offered to 'spare no expense' in upgrading my truck to include all these modern safety improvements for me, I would politely decline the offer.

I haven't driven my deuce in the rain yet, but I'm sure I'd agree that the wet traction leaves something to be desired. To a large extent that can be compensated for by planning ahead and driving carefully. Changes in vehicle speeds? I can still only go 55, and that isn't enough speed to cause even my rotten old tires to fly apart.

Maybe the Global Security article was suggesting that NDCCs were unsafe for some of the newer, faster trucks?

Regards,
Jon

cranetruck · 01-15-2007, 06:13

Of course, all tires have a speed rating, even new radial off road heavy lug tires have a rated speed limits of 50 or 60 mph.
The Michelin super singles are not that great on wet pavement either, from what I have read, and with weaker sidewalls not the best choice for rough terrain either IMHO.

I sipe my tires for better wet pavement traction and use chains for mud and snow, where no tire, regardless of tread, bias or radial, new or old design can do well. The CTIS is not a final solution either.

Off road, if the tire spins, you have lost traction.
Used correctly, the deuce with NDCC's can be safe.

(This should stir up some arguments.

)

cranetruck · 01-15-2007, 06:25

What's really unsafe are worn tires. How good is a 40,000 mile tire at, say 35,000 miles?

clinto · 01-15-2007, 06:51

Although the article is correct, a good (responsible, thoughtful and intelligent) driver can overcome quite a few engineering, manufacture and obsolete deficiencies.

RF202 · 01-18-2007, 00:17

Traction is governed some, by tread design, but most of a tire's traction comes from its ability to conform to the ground. Just as in braking, it's all about how much of the tread face contacts the surface, be it asphalt or dirt. If you look at a heavy radial truck tire, properly inflated, on uneven ground, from the rear, you will usually see that a portion of the tread does not contact the ground. A radial, for the most part, is designed for long wear life on the tread and high temperatures. It does not have as much strength in the sidewalls as the older bias ply tires. There may well be some exceptions to this, but it applies to the vast majority of radial truck tires. Military radials are probably the ONLY exception. We ran 11:20's on the rear of our civilian trucks for years, and never had any problems. Offroad traction was unmatched. In fact, the old NDCC's perform a lot like ag tractor tires.

mtech · 01-18-2007, 10:29

Obviously new tires/designs are not always the answer. If you recall the issues that Firestone had a couple years ago. I haven't experienced anything like that with the NDCC's on my deuce.

ARMYMAN30YearsPlus · 01-18-2007, 10:41

I think a big part of this is that we transporters are now seeing more combat related attacks than a lot of the infantry armor teams. Go figure I have been screaming this for over 25 years that we needed better protection and capability in the trucks we drive for the Army. In Iraq and Afghanistan a big part of getting through safely is by driving like a bat out of H. Drivers try to drive as fast as they can to get through areas safely. We outfitted all of our M 915 tractors with radials on one mission back in 86 and they got better milage and less flats from that point on.

I agree with John though my truck is a 1970 I will upgrade things like lights and other safety issues but since my tires are in good shape the tread design just will stay the same and as Clint said drive safely and defensively and in 99% of the time you will be all right. Thank God that we do not face IED's like we did in Iraq they blow the whole safe driving technique out the window.