Tire pressure

[1212FBGS]

Hey I cant find that page that had the reco tire pressures on it. I am taking my liner to the alignment shop and need pressures for 22x15 MH and 23x15 goodyear front runners
thanks Kent

[Sumner]

They don't say on their site:

http://www.racegoodyear.com/products/racect10.html

But for the 300 mph landspeed tire they say 50 and 70 depending on which tire you have.  Look here:

http://www.racegoodyear.com/products/racect19.html

c ya, Sum

[1212FBGS]

I think Ken Walkey posted something a wile ago but for the life of me I cant find it Hopefully some one will know I want to set the pressures before she gets aligned

[Glen]

Kent
I think it was Earl Wooden that posted it on the SCTA web site. It could be in the archives maybe you can contact Ed Saferak and see if he still has it on file.
Glen ( now back to the fun)

[Richard Thomason]

we set pressures to adjust run-out. We only run MT's. Front to rear, side to side may vary from 60-95 lbs. Never go outside those limits.
rht

[1212FBGS]

Hey guys thanks. I set the pressures at 60 for alignment. I checked the tire size at 60 the MH were identical in size the rear goodyears were 1/16" off at 60! sorry Richard, MT's suck I have had really bad balance problems several times and when they screwed me a couple of years ago I swore I would never buy another MT in my life. I wont even put them on my grandma's crown vic. I'd change em if I was you especially if they are so far out of size. When I buy tires I request they measure them and get the closest pair. I had to send a pair back to Summit that were out 3/8 once. I guess i'm pretty lucky to get closely sized pairs. My alignment is done, they say i'm spot on, cant wait to get r on the boost on the 23rd.
yours in spoprt
Kent

[hitz]

we set pressures to adjust run-out. We only run MT's. Front to rear, side to side may vary from 60-95 lbs. Never go outside those limits.
rht

Richard, could you explain a little more about adjusting run-out with air pressure? Is this run-out of the tire in the radial direction? I'm new to this LSR, so I need to ask alot of questions. would appreciate your thoughts.
I've bought3.5/22.0-15 M&H tires for the front and MT 29X4.5-15 for the rear of a G/Gl Lakester that I'm building. Since then I've had second thoughts about running the MT fronts on the rear. I know a lot of people run the Goodyear front runners on the back.

[Richard Thomason]

Yes MT's are a pain to find pairs that have the exact same circumference. It it pretty critical on our front wheel drive with a spool. We run the 15" and only the 6and 4's. They are a much heavier tire than the std. We tried running the Goodyears (don't remember the "D" number, but that is critical too). They were always the same circumference and balanced reasonably well and did not leak. Alas, they chunked silver dollar sized rubber chunks at 300+. If I were running below that speed, I would run the Goodyears. Also there is an upper weight limit, don't remember what it is. I know Nish and Feuling run/ran Goodyears. They shaved the majority of rubber off, at least Nish shaved his off, I don't remember if Feuling shaved his or not, but I do remember that he had special Goodyears when they first came out. To answer the other question about tire pressure and runout, we adjust pressure until the circumference is the same on each axle. Now of course the big question is, what happens to the circumference at rotational speeds. Don't have a clue, but what we have been doing works so well that I'm afraid to try anything different. I do remember that we discovered the runout differences on a cement strip. When we first started, we just assumed that tires from the same mold were the same size. NOT! The car runs so straight and true now that I'm interested in more MT's 6 and 4's.

[JackD]

Rollout, not run out.
Runout might go away after use just like a cold tire will thump for awhile until you drive it a bit. If a tire is built carefully and centered in the mold. it should balance pretty close. If it is not centered so as to cause more material to be on one side, that is the worst of the balance problems. Automated molds are usually pretty good, it is the hand laid up tires that can give you the trouble if done sloppy. Most often balance problems come with a new tire that is built equal all around but has a flat spot from stacking or sitting in one spot. Before you trash a tire it needs to be handled correctly to mount it and make it round. If your wheel will bolt onto a vehicle, put it on with air on the low end and break it in by driving it around. Be very careful not to cut it because race tires don't do very well around road hazards. If you don't want to put it on the ground, you can still spin it and get a flat spot out and even cause a tire to grow a bit to match roll out with a heat lamp.
Chunking is a product of the bond between the tread and the casing parting as the result of the forces that are made worse with the heat. Shaving will reduce the forces and breaking in a tire will help more than you might imagine.
The tires you mention for the Fueling car were 6ply Goodyears made in the same mold as the drag tires but the extra plys gave it more physical strength to allow higher pressures and reduce the flex and heat related failures at speed.
If a tire is built wrong it is usually because their is more rubber on one side and if the casing is centered, shaving can save it. To judge a tire by just putting it on a rim without the complete methods will fail many times.