Kelsey flat-spotting nylon tires, pass PV?

[Michael J.]

I am curious about what happens if you put your C2 into PV, and you have the notoriously flat-spotting nylon OEM type tires Kelsey sells. Will all that flat-spotting for 10 miles or so make you fail?

[Dave S.]

Re: Kelsey flat-spotting nylon tires, pass PV?

I am curious about what happens if you put your C2 into PV, and you have the notoriously flat-spotting nylon OEM type tires Kelsey sells. Will all that flat-spotting for 10 miles or so make you fail?

Why should that cause a failure.? Original Nylon cord tires were just like that. If they didn't do that it may be a failure.

[Michael J.]

Re: Kelsey flat-spotting nylon tires, pass PV?

Thanks, I was hoping the kathunk-kathunk that goes on for a while should not be a failure, but knowing how picky the judges are about noises, etc. and since I don't recall any of that flat-spotting noise back in the day, I was just concerned and thinking maybe a polyester cord tire would be better, though the nylons are best for flight judging as OEM.

[Terry M.]

Re: Kelsey flat-spotting nylon tires, pass PV?

You may not recall "kathunk-kathunk" back in the day because you drove your car every couple of days.

If you do the PV in reasonably warm weather the "kathunk-kathunk" should not last 10 miles. If you are really worried about it, take your car for a nice long drive a day or two before the PV.

[Michael J.]

Re: Kelsey flat-spotting nylon tires, pass PV?

Good advice, thanks Terry! And a good excuse to have it out of the trailer for the last part of the Road Tour.

[Terry M.]

Re: Kelsey flat-spotting nylon tires, pass PV?

Good advice, thanks Terry! And a good excuse to have it out of the trailer for the last part of the Road Tour.

And another opportunity to check all those items the Team Leader looks for during the PV.

[Michael J.]

Re: Kelsey flat-spotting nylon tires, pass PV?

Very true, chase down and eliminate all those rattles, leaks, and wind noise.

[Jim T.]

Re: Kelsey flat-spotting nylon tires, pass PV?

I do not have the type of tires you have Michael, however with long sitting time on my cars I inflate the tires to 45-50 lbs of air when not being used. When they are going to be driven I deflate the tires to the recommended pressure for driving and don't have the flat spots from sitting in one position for a long time.

[Michael J.]

Re: Kelsey flat-spotting nylon tires, pass PV?

Thanks Jim, that is a good tip, I need to try that. Those cradles and putting the car up on jacks are just way too much trouble.

[Peter L.]

Re: Kelsey flat-spotting nylon tires, pass PV?

Mike - If you could only add an original battery that will certainly fail at the most inopportune time & then you won't have to worry about the tires. Pete

[Michael J.]

Re: Kelsey flat-spotting nylon tires, pass PV?

Mike - If you could only add an original battery that will certainly fail at the most inopportune time & then you won't have to worry about the tires. Pete

[Brian M.]

Re: Kelsey flat-spotting nylon tires, pass PV?

That's too much pressure. JMHO

[Tom S.]

Re: Kelsey flat-spotting nylon tires, pass PV?

I park on 4 pieces of Blue SM Styrofoam 1" thick cut 16" x 16" with 40 pounds air pressure over the off season and in over 10 years have never felt any sort of flat spot with my 6x70 x15 blackwalls.

[Duke W.]

Re: Kelsey flat-spotting nylon tires, pass PV?

If the maximum cold pressure placarded on the sidewall is 35 psi, then 40-45 psi during storage is okay and a good idea. In normal road service cold pressure will increase by up to about 5-6 psi and 10-12 psi in severe service like hot lapping a race track, and this level of pressure is well within the tire's structural limitations. It takes something on the order of 100-150 psi to burst an automotive tire.

Nylon cord tires tend to temporaily flat spot. That's why nylon cord bias ply tires were relatively rare for automotive applications, but are SOP for aircraft. Modern H and above speed-rated radial tires that have spiral wound nylon cap belts can also tend to temporarily flat spot if they sit a long time with insufficient pressure, but they go round again after warming up from driving.

Allowing any tire to go flat on the car or spend a lot of time at very low pressure can cause permanent damage, so it's a good idea to visually inspect and check actual pressure level every couple of months on a car in storage. On average tires lose about one psi per month, but temperature also affects indicated pressure - about one psi per ten degrees.

The optional nylon blackwalls during the C2 era were considered "high performance" tires as was the nylon cord F70-15 from the C3 era.

Duke

[Michael J.]

Re: Kelsey flat-spotting nylon tires, pass PV?

Thanks Duke for the info. The Kelsey nylons I have are the only tires that do this, including my vintage bias-ply Polyglas and all my radials.