Topic: Lowest tire pressure for flat track racing?

[wreckitralph34]

I'm currently building my cb550 to race in the Born Free Sportsman Cup on August 17th (3/8 mile dirt oval). From my Jeep experience we air down our tires to improve traction off-road so what do you think is the lowest pressure I can run on my tubed tires? Front tire size is stock for the 550 but I have a 16" cb750 rear wheel with a 5.10-16 tire. Trying to get as much traction I can without messing up a tube or blowing a tire off , etc.

[lrutt]

depends on track surface and tire. You want your tire to step out in the corners and slide. Low pressure would make it handle and feel wonky. You really need to test during your warm up laps and see what works. I'd say start near 30 and go down from there. If you have good grip and the surface is good and sticky, you'd likely stay there. If there are a lot of marbles and the track never sets up, you may go down in pressure. I used to run a TT500 Yammie in short track years ago.

[wreckitralph34]

depends on track surface and tire. You want your tire to step out in the corners and slide. Low pressure would make it handle and feel wonky. You really need to test during your warm up laps and see what works. I'd say start near 30 and go down from there. If you have good grip and the surface is good and sticky, you'd likely stay there. If there are a lot of marbles and the track never sets up, you may go down in pressure. I used to run a TT500 Yammie in short track years ago.

Ok Thank you for the info. I'm expecting the track to not have good grip considering some of the reviews and videos of the track. I'll start at 30 but what would be the lowest pressure if I have to go down? I also weigh about 220-230 if that helps. And the bike is a lighter than stock since it doesn't have any lights or extra factory equipment on it.

[jgger]

Tire pressure is just part of the equation,  suspension will play a big part in it too, they kinda go hand in hand. If you are not running bead locks I wouldn't go much lower than maybe 26 lbs. Too much bite and the tire will spin on the rim and rip the valve stem out of the tube. Keep an eye on the angle that the stem comes out of the rim, and keep the locking nuts either off or very loose. On the 4x's airing down is to increase the footprint and not sinking into sand or mud and is not subject to side pressure in the same way a flat track bike is, you dont want to roll the bead off of the wheel.

Try it with 26 to 30 and if your rear shocks are adjustable maybe soften them a step or two if it is sliding too much. Unpredictable tire roll is not a fun thing and is increased as tire pressure drops.

That's my $0.02.

[wreckitralph34]

Tire pressure is just part of the equation,  suspension will play a big part in it too, they kinda go hand in hand. If you are not running bead locks I wouldn't go much lower than maybe 26 lbs. Too much bite and the tire will spin on the rim and rip the valve stem out of the tube. Keep an eye on the angle that the stem comes out of the rim, and keep the locking nuts either off or very loose. On the 4x's airing down is to increase the footprint and not sinking into sand or mud and is not subject to side pressure in the same way a flat track bike is, you dont want to roll the bead off of the wheel.

Try it with 26 to 30 and if your rear shocks are adjustable maybe soften them a step or two if it is sliding too much. Unpredictable tire roll is not a fun thing and is increased as tire pressure drops.

That's my $0.02.

Sweet. Thank you for the info. I'll start at 30 and see what happens. I'm not racing to win. Just trying to have some fun but also don't want my bike to be super loose and increase the chance of #$%*ing myself or the bike up. Its gunna be my first time racing a bike