Originally posted by Bad-Andy
OK, I have two problems here. Any advice or help would be appreciated. And sorry about the long post. I'm at the point of losing interest in 1/12th scale I'm so frustrated right now.
What is the smallest rear tire diameter that everyone usually considers to be at the point the tires need to be replaced? My problem is that when my rear tires get below 1.8" in diameter the car really start to fall on it's face and slow down. Everyone at our track runs around a 1.6 rollout, but no matter what I adjust my rollout to the car never gets any better. But as soon as I put new tires on the car is right back to normal. I start my rear tires at 1.9" diameter. I'd like to think I can get some more life out of them and not have to replace them every .1" of wear
Oh, and since someone may ask. I'm running a monster stock, 767 brushes, with green and red springs.
My second problem I'm in the market for a new car but have struck out everyplace I've looked. I'm leaning towards the Speedmerchant Rev4, and thought I was actually getting one sent to me. But I was refunded my money after three weeks of the place I ordered it from teling me it would be in stock in a few days, and then finally admitting they had no idea when they would be getting any kits. Where is everyone ordering them from? Also we are going to be running 1/12th scale 19T outdoors on asphalt this summer, would the Rev4 car be a good choice for this?
Like ODPurple says, you have to keep adjusting your pinion/spur combo as the tire decreases in size to maintain optimal roll out and lap times. Your car may also be "falling off" due to ride height. Make sure you always maintain the optimum ride height. For me it's 3.5mm in the front and 3.0mm in the rear. Our track requires a minimum ride height of 3.0mm and I like the way my car handles with a slight rearward rake, thus the 3.5mm in the front. You adjust your ride height to compensate for tire ware in the rear with the rear axle ride height adjusters and in the front with thin shims or washers. When you get below the 3.0 minimum ride height, your car might allow the outside edges of your chassis to come in contact with the racing surface therefore scrubbing off speed in the corners. Especially on T bar cars due to the batteries being further from the center line of the car.
Also try a green spring on the positive and a blue spring on the neg on your Monster Stock motor.