BJ8 Tire Pressures

[dougsmarkIII]

This summer I had Nexen 165/80-15 tires installed on my '66 BJ8. I used "Search" with no luck. What pressures do you members think I should use on a normal/daily basis.

Doug

 

[RAC68]

Hi Doug,

Originally, if I remember correctly, the Dunlop RS5s were 24lbs front 26lbs rear. When they wore out in 1965 and switched to Pirelli Cinturato radials, I was told to up the pressure and ran at 26lbs front and 30lbs rear.

Recently, I was informed that my occasional non-puncture flat was the result of tube chaffing. Since today’s tires are tubeless, tube movement was a common occurrence and could be prevented by running 32lbs front and rear. I was initially concerned that both ride and handling would be negatively affected by this high pressure but I have been running 32lbs this summer on my new 165 Vredesteins and find no negatives.

Ray (64BJ8P1)

 

[BigGreen]

For those who are used to Psi and kilo's ;-)

https://en.wikipedia.org/wiki/Atmosphere_(unit)
or
www.soccerballworld.com that explains it like this;

To convert BAR (KGS) to PSI (Lbs.):
Answer = 14.5037 X The amount of BAR(KGS)

For example: A soccer ball has a recommended pressure of 0.6 BAR labeled on it. To convert BAR in Pounds Per Square Inch (PSI), multiply 0.6 times 14.5037. The answer is 8.7 PSI or Lbs.

To convert PSI (Lbs.) to BAR(KGS):
Answer = .068948 X The amount of PSI(Lbs.)

For example: A soccer ball has a recommended pressure of 7.9 Lbs. (PSI) labeled on it. To convert Pounds Per Square Inch (PSI) into BAR, multiply 7.9 times .068948. The answer is 0.545 BAR.

So 32 Lbs equals about 2.2 Atmosphere

Hans

 

[Jeepster]

I run 32 lbs on my BJ8 with Kumho 165/80/15 as recommended by my tyre dealers. Seems to work fine.

 

[bob hughes]

When I got my BJ7 from a Healey restorer he said 30 all round,

I have been doing that for 9 years now and no problems.



Bob

 

[dougie]

Depending how and where I'm driving, I run between 30-32 psi in my 205 Dunlap Sports. It handles great and holds the road very well.

 

[twas_brillig]

Had to stop in a hurry today - right front tyre locked up, and the car was squirrely - moving back and forth in the lane.
Checked pressures tonight and the fronts were 25.5 psi and rears 28; I've run them up to 31-32 and will (ideally) try a panic stop in some safe location tomorrow and see if that makes a difference. I've been running (I thought) 28 psi all round; Vredestein Classics on 72 spoke rims; 185s if memory serves.
Doug

 

[dougsmarkIII]

Thanks for the replies all. Actually the new tires for the BJ8 are Kumho. I got the Nexen brand mixed up tire shopping for another vehicle. Like Ray stated the original Dunlops were 24 psi front and 26 psi rear. That's appears a little low so that's why I asked for experience and recommendation of other owners. I think I will try 30 front and 32 rear psi. The 30 psi all around sounds good also.

Doug

 

[twas_brillig]

I did a test stop yesterday with 31 psi all 'round; partially locked right front; a bit of instability but much better than the previous 'stop in a hurry' where it turns out I was running only 25.5 psi in the fronts.
According to https://www.rmahc.com/healeyspecs.html the weight is about 49% on the front wheels for the various six cylinder models.
Near as I can tell from my notes, I was running 28 psi at both ends with the Vredestein Classics; I'll maybe try some hard stops next summer with the 28 and see how it feels.
Doug (the more northern Doug)

 

[elrey]

Hope you don't gyre and gimbal and all remains frabjous!

 

[twas_brillig]

Frabjous it is, out here in the Wabe. Darn mimsy's keep plugging up the rad, though.
Thanks Elrey - got a chuckle!
Dougie: we're running 185 70 15s on 72 spoke wires; do you have any clearance issues with your 205s?
Thanks again Elrey!
Doug
(for those who are wondering about sanity: check Lewis Carroll's "Jabberwocky" from "Through the Looking Glass")

 

[twas_brillig]

Has anyone run across equations for calculating what tire pressures should be for given sizes, type (eg radial), and vehicle weights etc? Our BJ7 is running wider rims and tire widths than original; our VW beetle based dune buggy (for example) is running 15 inch rims that are 7 inches wide at the front and 8 inch at the rear and rubber to match - somewhat wider than the stock Beetle was running in 1962 and nearly 1000 pounds lighter.


Original A-H factory recommended pressures with (presumably) cross ply/bias ply tires were, according to my reprinted Shop Manual):

BN4 & BN6 (page 8)
Tyre sizes: 5.90-15 tubeless or 5.90-15 road speed (optional alternative)
Pressures:
Front: 20 psi
Rear: 23 psi
Rear (full load) 26 psi
Sustained speeds over 85 mph (137 km/h): Increase all pressures by 6 psi


BN7, BT7, BJ7 and BJ8 (page 18)
Tyre sizes: 5.90-15 road speed (with tubes)
Pressures:
Front: 20 psi
Rear: 25 psi
Maximum performance speeds: increase all pressures by 5 psi

 

[Ed_K]

Hendrix W.W. said to run 28 lbs in my Nexens which I got this summer.

 

[wheelguy]

28 to 30 lbs work well. Remember tire pressure increases with heat 3 to 4 pounds So for winter you may want to go up to 30lbson 165/15 tires. Wheelguy