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tire pressure with radials

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bighealeysource

bighealeysource

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Hey All,
Know what the owners manual says for tire pressure but
what should I be running with 165/80 x 15 radials on
my BN6 ? Got tubes as using correct 48 spoke wires.

Also, what is a "normal" operating temp once warmed up ?

Thanks for your help with a couple of questions I should
know the answer to !
Mike
 
bighealeysource said:
Hey All,
Know what the owners manual says for tire pressure but
what should I be running with 165/80 x 15 radials on
my BN6 ? Got tubes as using correct 48 spoke wires.

Also, what is a "normal" operating temp once warmed up ?

Thanks for your help with a couple of questions I should
know the answer to !
Mike
Click to expand...
I bought radials from Hendrix ans was told to run 28lbs all the way around. If me memory serves me correctly, about 3o years or so ago, I was running 30 in front and 26 in back.
Patrick
 
Don't know what's correct but I do know 30 all around is a little high, my car will "bounce steer" with that much. I prefer 28 in rear and 26 in front. Car runs stable and tire wear is normal. I always thought most BMC cars needed more air in rear.
 
I have been told that thee should be 2 more pounds in the rear than the front. I have also been told that radials should never have less than 30 psi in them but I really have no idea if this is correct. It would be nice to have a realistic explanation on this issue by someone in the know. Have a good day!

John
 
John_Progess said:
I have been told that thee should be 2 more pounds in the rear than the front. I have also been told that radials should never have less than 30 psi in them but I really have no idea if this is correct. It would be nice to have a realistic explanation on this issue by someone in the know. Have a good day!

John
Click to expand...
Soundfs like time for <span style="font-style: italic">Hendrix</span> to chime in??
Patrick
 
Johnny said:
Don't know what's correct but I do know 30 all around is a little high, my car will "bounce steer" with that much. I prefer 28 in rear and 26 in front. Car runs stable and tire wear is normal. I always thought most BMC cars needed more air in rear.
Click to expand...
I believe there's more weight in the front so it would seem that the front tires need more airpressure??
Patrick
 
What I've heard/read is that running with a little less pressure in the rears helps reduce understeer. It seems logical because with less pressure you'd increase the rear tires' footprint and therefore grip. I usually run 2psi less in the rears, and when I first tried it I thought there was a bit less understeer, but I didn't have access to a track to really test and I'm probably not astute enough to tell for sure anyway. I cut it to 1psi less if I'm hauling a passenger and baggage. Sometimes, though, things that sound logical ain't necessarily so (but that's a topic for another thread).

Also, unless you have a calibrated gauge you don't know for sure exactly what pressure is in the tires, and it'll vary from day to day.
 
I've been told 30 front and rear on radials. Less increases the wear on the side walls leading to failure.I try to run 30 front and 31 rear at 6400 ft.(as I live at that altitude) and a pound more at sea level. I'm have not seen any center tread wear and they will be replaced due to age before that becomes an issue. You get better fuel economy and firm handling at that pressure.It would seem to me that lower pressure would give more traction but sideways sway and role.
TH
 
This is interesting and I will be watching to see if a consensus evolves. I wonder if wear issues are really that important since most of us don't put enough miles on to wear out the tires. I think mine will be replaced from age before wear, so my focus will be on performance versus sidewall wear. Looks like I have too much in them now. 26-28 pounds looks almost flat to me.
 
Thanks y'all for the feedback. Put 30 pounds front and rear and will see
how it rides and handles. Then lower if needed !
Regards,
Mike
 
It's not the wear on the sidewall but the break down do to excess bending and can cause tire bulge or side blowout. Don't forget that there is an inner tube that is flexing too which creates heat. When I raced my MG-B in the 70's, a tire company called Simpretti did an extensive study on racing tires and heat. I don't know what is the correct pressure for our cars but I don't want to be too much off. I got a bulge at high speed that was 3 inches wide (from the tire surface inward so not seen from the side of the car). I stopped cause I heard a noise from the rear. It was rubbing on the body and could have lead to a real disaster. Simpretti replaced the tire and sent me the report on heat.
 
FWIW, I bought a new Mustang a couple years ago. I do my own routine maintenance. I have a Bourdon-tube (dial) gauge which I believe is very consistent but seems to read 2-3 pounds low; e.g. if the gauge reads 30psi I believe it's actually 32-33psi (I know--I should get it calibrated). Ford calls for 32psi all around so I filled to 30psi per my gauge.

I rotated at 5K and 15K miles. At 15K, I checked the tread with a tread gauge and found that the rear tires had worn 1/32" more on the center than the outside of the tread, indicating the rears were slightly overinflated. Since then, I've run--per my gauge--28psi in the rears and 30psi in the front. It seems to me the rearend was a tad less squirrelly with lower pressure in the rears. We'll see what story the tread gauge tells.

My BJ8 still has a bit too much positive camber (~1.5deg)--and the outer tread wears much faster than elsewhere--for me to get a good reading with the tread gauge (I do try to corner as hard as possible, too).
 
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