Drag Radial Tire pressure????

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4spd340Swinger

4spd340Swinger

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I have a stock 1969 340, 4sp, Swinger with a 3:91 Suregrip. I am starting to race the car in test and tune and wanting to go into Sportsman. Not a fast car but I am doing it for fun. I bought a set of MT drag radials since my redlines just wouldn't work. My question is, what tire pressure should I run? They will only be on the car when at the track. I have heard about 17 pounds but wanted some advice.. Thanks for your reply!
 
Rumor is (I have no first hand knowledge, i havent raced a stick car in decades) that drag radials are a poor choice for a stick drag car. Generally, drag radials like to dead hook, because they don't recover well when spun. Bias slicks can recover from a spinning tire start better than dr"s. Spinning start wheel speed can be desirable with a stick car.
That said, drag radials like more pressure than slicks. I would start at 15 lbs, and then go up from there till the 60 fts fall off.
 
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33IMP said:
Rumor is (I have no first hand knowledge) that drag radials are a poor choice for a stick drag car. Generally, drag radials like to dead hook, because they don't recover well when spun. Bias slicks can recover from a spinning tire start better than dr"s. Spinning start wheel speed can be desirable with a stick car.
That said, drag radials like more pressure than slicks. I would start at 15 lbs, and then go up from there till the 60 fts fall off.
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I had that exact problem (on a Fox body). I had radials on the front, so I thought it natural to use them on the rear. Nope. I had M/T ET Street Radials. I ended up with M/T ET Street R Bias. Completely different animals.
I put the radials on my auto trans Duster, but haven't tried them at the track yet.
 
Had best luck at 20 psi both A and B body cars. Cars ranged from 2800 lbs to 3600 lbs.
Only automatics.
 
I ran the radial slicks on my S/S `cuda at about 13-16lbs. It flat hooked.
 
15- 18 psi, depending, with MT ET streets on the 67 Fastback.
It all depends on the surface and temp I'm working with.
 
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I started the beginning of last season at 14lbs, (first time not on slicks, trying the drag radials), finished the season at 20lbs with no performance issues, and I like them. Modest burn-out, (1 or 2 cubic yard, or about a garbage bag or two, size of tire smoke), no dry hop, stage and go.
 
4spd340Swinger said:
I have a stock 1969 340, 4sp, Swinger with a 3:91 Suregrip. I am starting to race the car in test and tune and wanting to go into Sportsman. Not a fast car but I am doing it for fun. I bought a set of MT drag radials since my redlines just wouldn't work. My question is, what tire pressure should I run? They will only be on the car when at the track. I have heard about 17 pounds but wanted some advice.. Thanks for your reply!
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ET Street R (Bias), ET Street R, ET Street S/S, Pro Drag Radial, Pro Bracket Radial and ET Drag Air Pressure Guidelines

Started at 16, now up to 20 psi which is what I run them at now (w-automatic) They always dead hook. Can’t say I’ve seen any change in 60’ time specifically related the psi changes (more related to bias slicks I believe) but tried anyway. Biggest thing is doing enough of a burnout just till you see smoke, no need to sit and smoke em up. At least that’s how I get best performance.
 
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I ran the MT Street Rs last season at about 15 psi. I run tubes with them. They hook nice, and feel fine on the street.
 
I run mine at 15psi, but just like spark plugs, you can read your tire marks to determine how much pressure is ideal for your setup. Over & under inflated tires will make a distinct pattern on both prepped tracks and the street. I keep a notebook with track temps, tire pressures, and my caltrac settings. Gives me a reference point for when I'm working off a hangover from the night before

I've also noticed that shorter burnouts work better with MT D/R tires. Mine were slick as snot if I super heated them coming out of the box
 
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