I know I've read it here before... but my thread searched dodn't bring it up...
30x3 1/2" clincher tire pressure? I thought I read 55lbs min... many prefer 65. Tire shop said with 4 ply tire, they wouldn't put more than 32-35 in them. "I" could put whatever I wanted in them, but they wouldn't. I explained as ined they needed higher pressure to keep the tire and tube from spinning on the rim.
Don't want to start an air war.... but what is the consensus, again, please? I now have 3 new tires...
Clinchers need 60 PSI to prevent them from slipping on the rim.
The guys at your tire shop don't know about clinchers. I agree on 60 psi for those.
60 psi for me also. I ran 50 psi in the past and had 2 tires roll off the rims before I learned my lesson.
I run 55 to a little over 60 but 60 is good. Anything less, you run the risk as Dean said, tires moving on the rim shearing the valve stem.
And Iím good with 60 PSI on clincher rim T tires too !
I run 55 only because I don't want too much pressure punishing my lightweight Runabout.
Being a novice I listened to another novice and ran 60 psi in my model A 21 inch tires with no bad results. Just recently learned different and will run them at 32 psi when I get it running again.
Probably lucky that I didn't blow out a side wall.
When I was a young lad I used one of those tire pumps that you dialed in the pressure need and blew out a perfectly round piece of the tire on my bicycle,
Bad day, I had to push my Indian bicycle 5 miles (up hill all the way =:-)) To get home.
The Overland ownerís manual says 80 on the same clinchers a T uses.
Iíve seen two ply bicycle tires that said 70 right on the sidewall.
All the early reference materials I have call for 20 psi per inch or 60 for 3" tires and 70 for 3-1/2. God only knows how they got to that tire pressure with hand pumps. Probably why so many tires look under inflated in those period pictures. That is what I run my cars at but I reduce the pressure to 30 psi when the cars are being stored and I keep them off the ground.
Ford recommended 55 psi on the clinchers, and 27psi to 30 psi on rear for balloon tires.
The airing up of the clincher at 60 psi is best, takes care of any slight lost over last check of tire pressure.
Find that a check at least each month works for me
Now the modern car gives me a check pressure light!
I have sheared off a valve stem in the past so I now run 65 lbs pressure in my clincher tires.
For more info you can refer to the sidewall statement found on many clinchers.
These are Firestone, this one is New Zealand mfg, older, reads max.load pressure min 50 psi.
This newer Firestone, think from Vietnam, reads max. load pressure min. 65 psi.
The Ford is light weight car, but if loaded up 5 passengers, the higher pressure is better.
Many times I just run the compressor up to 60psi min- bit over, up to 65 psi is OK.
I'm with Dave Wells about 55 lbs. being the best on a light little Runabout. I ran 60+ once and had the rear-end jump sideways about a foot as i went around a corner and hit a bump simultaneously. Not a great feeling. Heavier Models can probably run 60+ and never notice a difference. Just my 2c.
Hmmm.... a topic for another post. My tail end often wants to skip out to the right, and tries to pass me. I thought the frame may be tweaked, rear axle not square, etc. Could uneven tire pressure do it?
The reason we need to run high pressure in clinchers is to avoid shearing the air valve off the inner-tube. -Higher pressure forces the rubber clinchers more tightly against the rim, thus preventing tire slippage. -If the tire slips along the rim (and this tendency is strongest during heavy braking), the inner-tube gets stretched at the point where the air-valve pokes through the rim and that can cause it to tear apart. -This problem is much more prevalent in the case of the rear tires because they are subjected to the fore and aft loads of acceleration and braking. -Not so, the front wheels, the most significant problem of which is the kind of excessive side-load you get when rounding a corner at too high a speed (which is not only bad for the tires, but for the wooden spokes as well).
Point is, you have some "wiggle room" when it comes to deciding on the proper inflation pressure of your front tires, and if you run them at, say, 50 pounds instead of 60 pounds, for the front passengers, the car will ride much more smoothly. -But as always, take corners slowly so as to avoid peeling the tire off the rim or shattering the spokes.
There's not a whole lot we can do about reducing the acceleration and braking impulses at the rear wheels. -In a Model T, those forces are already minimal compared to most any other kind of car and reducing them further is not really possible. -The usual vacuous advice applies and all you can do is inflate to the recommended pressure and drive gently.