b'TECH TIP PAGE Tech Tip 7: Rookie Racers often dont know how critical tire width to rim width ratio is to grip. We often see people putting good width tires on narrower than ideal wheelsusually to suck the sidewalls in for fender clearanceand experience significantly less grip. An example is when Racers want to put a 315 tire with 11.8 of tread on a 10.5 wheel. Not good. The optimum wheel width for grip varies with sidewall height & design. Stock Car bias ply tires have 6-7 sidewalls & respond well to wheels around 10% wider than tread width. Modern cars with 18 wheels & 30 or 35 series radial tires have 3.5-4 sidewalls & respond well to wheels equal to tread width or 2-3% wider than tread width.If the rim to tire ratio is narrow, the sidewalls are bulging out past the rim, and we run less tire pressure to achieve even tread wear. This is bad. The lower pressure is not enough to keep the tire carcass in the proper shape with high G side loads (even worse with taller sidewalls). So, the tires roll under significantly during cornering. This distorts the tread contact pattern.This is WHY we have less grip with narrow wheels. Wider wheels require more tire pressure to achieve even tread wear & this keeps the tire carcass in the proper shape with less roll under. For 18 wheels with radials, treaded or slicks, we recommend: For 275/35-18 tires with 10.1 of Tread, we recommend 9.5 min, 10 is better, 10.5 is best. For 315/30-18 tires with 11.8 of Tread, we recommend 11 min, 11.5 is better, 12 is best. For 335/35-18 tires with 12.7 of Tread, we recommend 12 min, 12.5 is better, 13 is best.Tech Tip 8: Shocks are the final frontier to making cars have more grip to brake, corner &accelerate better & faster. One of the most important measurements of a shockand the leasttalked about by average car guysis its response time from input to control. From small input, like minor track surface irregularities to larger inputs, like bumps, how quicka shock responds IS the most important key. It does not matter what your shock valving isor that it is adjustableif the tire isnt loaded on the track surface! For this reason, any designtechnology that makes a shock respond quicker, is valuableand slow responding shockdesigns are not acceptable for winning track performance.The first important choice youll make is between Hydraulic Twin Tube or Gas ChargedMonotube. Its not really a debate. Twin tube shocks respond in the 20-30 millisecond range & monotube shocks respond in the 4-8 millisecond range. That is a huge difference! Running twin tube shocks in a race car makes no sense, unless the rules require it. The ARS, Fox, JRI & Penske race shocks we utilize are all of the superior monotube design. Testing has shown our ARS valved shocks to be the absolute best for autocross, while our Penske valved shocks dominate on road courses. JRI shocks are the best dual purpose autocross & track shock, but expensive. Our Fox Racing Shocks are very close in grip for 1/3 less money.AllKoni, Vikingmost QA1 & AFCOare inferior twin-tube design. As far as coil overs are concerned, the superior, quicker responding, higher grip monotube shocks start around $500. The inferior, slower responding, lower grip coil-over shocks typically (but not always) start around $300. $200 a shock is a trivial price difference when it comes to such a performance gain. Scrimp somewhere else. Buy the monotubes! 49'