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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| Tire pressure BFG Mud Terrain
Hi, I bought 235/85-R16 tires to my 1984 SWB 300GD with original 16"x6" MB steel rims.
What tire pressure should I use, anyone with any experience?
The MB table only got the 205-R16 tires for these older models... |
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kerry460
Elite Veteran
Date registered: Apr 2006
Location: tasmania australia
Vehicle(s): 1984 300GD LWB WAGEN
Posts: 611
| RE: Tire pressure BFG Mud Terrain
G,,day the very best way is the 10% increase method. set cold pressures to whatever you think ie, 30lbs after a reasonable road drive 100 kilometers? check youre presures ,you idealy want 10%increase,in thiscase 33lbs .if the pressure has increased bymore than 10% youre cold pressure was too low allowing too much flex and therefore too much presure increase.
if increase less than 10% . cold pressure was too high ,not allowing enough flex and pressure increase.
adjust cold pressure starting point and try again .for it to work you must start with cold tyres.
i have used this method on rally cars ,race cars,4wds. it will also give you what difference you may need between front and rear.
this information originally came from a technician at a tyre manufacturing company.
i stress it is the most accurate way.
cheers kerry. |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Re: Tire pressure BFG Mud Terrain
Kerry, great method, I will try it. Given that, what are the pressures you run on your GD. Are they different front and rear? My G (SWB) has very even weight on each tyre. I would suspect then that the pressures should be close to the same on the SWB. Is there a recommended increase in pressure if the truck is laden with an extra 1000 lbs? Again a really great practical way of determining proper pressure for the exact application. Does this follow for motorcycle tyres too? Very cool.
Cheers,
-Dai |
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kerry460
Elite Veteran
Date registered: Apr 2006
Location: tasmania australia
Vehicle(s): 1984 300GD LWB WAGEN
Posts: 611
| RE: Tire pressure BFG Mud Terrain
G,,day yes it is a very practical and accurate way. i have to run 40lbs which seems high for 255x85x16 but they are on std 5.5 inch rims , moreflex? . i havent had a big enough load for a long enough distance to need to change rear pressure. i have that some of the top world rally teams are still using this method ,because it is so accurate, and allows for all variables ,
as for m/bike tyres ,i havent tried but i dont see any reason why it would be any different. they are still tyres that flex and develop heat.
cheers kerry. |
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kerry460
Elite Veteran
Date registered: Apr 2006
Location: tasmania australia
Vehicle(s): 1984 300GD LWB WAGEN
Posts: 611
| Re: Tire pressure BFG Mud Terrain
forgot to add it is 10% optimal increase irrespective of load .
so if you load up for a trip and your vehicle doubles in weight you still aim for a 10%increase over cold pressure,kerry. |
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460332
Date registered: Apr 2006
Location: Europe
Vehicle(s):
| Re: Tire pressure BFG Mud Terrain
Thanks Kerry, sound like a great method!
Especially I liked that it is race proven and 4x4 proven. 
The method also take the locale climate into effects, -whether you live in Morocco or Siberia!
Great!
Edited by 460332 5/12/2007 4:47 AM
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kerry460
Elite Veteran
Date registered: Apr 2006
Location: tasmania australia
Vehicle(s): 1984 300GD LWB WAGEN
Posts: 611
| RE: Tire pressure BFG Mud Terrain
G,,day yes tasmania or texas, morocco or mongolia . it works . just realise it is for (normal) driving conditions .
low pressure for offroad ,sand , rocks , mud , is a totally different thing.
cheers kerry. |
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dai
Expert
Date registered: Apr 2006
Location: Oregon USA
Vehicle(s): 300GD 300TD BMW R100RS Landini 80F
Posts: 2110
| Optimal Tire pressure Method
Outstanding. This method also eliminates the problem of tire pressure guage variability. If you use the same tool to determine the optimal setting it will be accurate even if the guage is missreading by a couple of pounds.
i am not surprised by the pressure you use. These trucks are heavy.
I will be trying this out today. Many thanks, Kerry. G' day to you.
-Dai |
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: Optimal Tire pressure Method
It would be interesting to see whether MB follows the same rules.
Can anyone measure a before and after on stock G500 (or any other stock configuration)
with the recommended pressures?
40psi on a 255/85R16 seems high - its a tire with much more volume than the stock 205R16 |
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: Optimal Tire pressure Method
here is how I find out the best street pressure for my vehicle with
non stock tires:
start with about 35 psi - run a white chalk line across the thread and
drive 100 ft - check the line - if it is gone from edge to edge, pressure
is good - if white lines are left towards the edge decrease pressure in
increments of 2 psi until line is gone completely
for long max speed freeway drives increase pressure by 10 psi |
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