1967 Bias Ply Redline tires

[John R.]

I have BF Goodrich bias ply redlines on my '67. All 4 were bought at the same time and therefore are the same age, etc. 1 tire has always had a very, slow leak, but just enough to be a pain. Have to put air in it every couple months. So finally took it off the car and brought it up to my local Goodyear to diagnose the problem. Their response was "old bias ply tires just do that". What do you guys think about that response? The other 3 tires never run low like this one does.

fyi: I asked the to check valve stem, seal around rim and if there were any tiny holes. They could not find any issues.

[Dana B.]

Re: 1967 Bias Ply Redline tires

This is what I would do... Air up the tire to MAX pressure and dip the suspect tire in a vat of water and look for bubbles. You will find the leak .
Dana

[Larry M.]

Re: 1967 Bias Ply Redline tires

What type wheels/rims are on your car..........steel or alloy?? It is possible that if alloy, the rim may have a casting flaw/porosity and leak air. This was not uncommon back in the day, although more modern alloy reproductions may have less of this issue.

I have near seen bias tires just leak air because of their construction.........and I have run my share of bias ply tires over the last 60 years.

Valve stem and Schrader valve insert are another two possibilities..........but you said you are already checking these.

Larry

[Ara G.]

Re: 1967 Bias Ply Redline tires

John,
Had the SAME problem. Mounted 4 Repop Goodyear redlines on my original DC rims (my silver 67 coupe). Two leaked, two held. Took them back to the garage that mounted them, they dismounted them and put bead sealer on the lips of the rims and one held air and one still will not hold air. Frustrated like you. Rims held air fine when they had radials on them...? Ara

[Tim G.]

Re: 1967 Bias Ply Redline tires

Ara, I see sporadic leaking on problem wheels/tires, too. Some are just fine, some always need to be topped off. I chalk it up to leaks at the bead.

[Joseph T.]

Re: 1967 Bias Ply Redline tires

Since bias tires are constructed with layers ( plies ) they have to be vented to release the build up of air in between the plies. This happens when in use on the car. If the air is not vented the tires will separate ( bubble up then blow out). Sometimes the venting holes in the tires , in the sidewalls are too deep. The tire becomes porous. I think this is what you are experiencing.

[Duke W.]

Re: 1967 Bias Ply Redline tires

A good seal should loose no more than about 1 psi per month, and pressures should be checked on a monthly basis.

I had a slow leak on a tire that I could not find, so I finally took it to a tire shop. While immersed it in the water tank the tech slowly wiggled the valve stem, and at one point we could see a tiny bubble slowly forming at the base of the valve stem. Replacing the valve stem stopped the leak.

Duke

[Timothy B.]

Re: 1967 Bias Ply Redline tires

I have a set of 205 radial tires mounted on 6" rally wheels installed on my 67 and had no issues with them until I went for a ride and the next day the drivers rear was flat as a pancake.

I removed the tire, aired it up to max and used a spray bottle with a touch of dish washing soap and found very very tiny bubbles from one small area around the bead. I took a bottle jack with a short 2x4 and broke the bead on just that side and cleaned the rim area but before putting air back I put a smear of truck tire bead grease that I used for tubeless truck tires around the circumference of the rim bead area and have not had any issues.

It seems like I parked the car with the tire clocking in just the right place which allowed the leak to show itself after sitting in the garage over night.