Bike and Rider Requirements

Bike Requirements You can have any type of 20" bike.  However, the lighter the bike, the more competitive you are. Standard Items That You Can Not Have Freestyle pegs Reflectors Kickstand Chain guard  Items You Will Have To Add 1/4" padding on top tube, stem & handlebar crossbar. Number plate  Miscellaneous Information About Your Bike Handlebars can not exceed 30" in width. ***  Handlebar grips are required & must be sufficient to fully cover & enclose all  metal & openings on the handlebar ends. RIDER INFORMATION: All riders must have the following gear & apparel: Helmet (preferably full-faced) with a working strap, no snaps. Long pants (waist to ankles). Long sleeve shirt OR short sleeve with sufficient elbow padding (elbow to wrist preferred). Enclosed shoes.

Gearing

In BMX racing, the gears you run can make or break you. It's important that you know how to change gears and when. Track conditions and other factors may warrant a gear change. You need to know a little about gears and gear ratios before making gear changes yourself. A gear ratio is the number of times your rear sprocket (or freewheel) turns for every full 360 rotation of your front sprocket (or chainring). It's really simple; you take the number of teeth on your chainring and divide it by the number of teeth on your freewheel, that gives you your gear ratio. For example, if your front sprocket is a 45 tooth, and your rear sprocket is a 16 tooth, then your gear ratio would be 2.8125 (45 divided by 16 = 2.8125). You then take that number (in this case 2.8125) and multiply it by 20 (the diameter of a BMX wheel). 2.8125 x 20 = 56.25 (the gear size). You can apply this simple formula to cruisers (BMX bikes with 24" wheels) by multiplying the gear ratio by 24 instead of 20. Easy enough? You can use this formula to help solve common problems. For example, which gear size is bigger - a 42/15 or a 45/16? Unless you have a gear chart handy, this formula is the only sure way to answer that question. In doing the math, you'll find that a 45/16 gear ratio is just slightly bigger than the 42/15. If your gear size is large (about 58 or greater), you will go faster, but you will accelerate slower; it will take longer to get going and 'wind out'. 'Winding out' or 'topping out' refers to when you are at top speed; pedaling the bike does not make it go any faster. Snapping out of the gate, going uphill, powering out of turns, etc. will be harder with a high gear. Conversely, a low gear size (about 52 or less) will result in faster acceleration, but lower overall speed. For most racing situations, a 55 gear size is almost perfect; not too high, and not too low. However, a different gear may be more appropriate, depending on track conditions. The overall slope of the track (uphill, downhill, etc.), length of the track, angle/slope of starting gate/hill, overall track layout, and the track surface are just some of the conditions that might warrant a gear change. Experiment with different gears and see what works best. You'll be glad you did. Gear Size Chart Wondering which gears you should be running?  Check out the chart below and maybe it will help narrow down those decisions.  The Top row of numbers is the number of teeth on your chain ring.  The Rear "XX" column is the number of teeth on your rear sprocket.  Where the two numbers intersect is your gear ratio for the gears selected.  What do these numbers mean?  Well for every complete revolution of your cranks you go that many inches.  For instance if you have a Rear Sprocket of 16 and a Front Sprocket of 43 and the size of your wheels is 20" X 1.75" then you would get 52.4, meaning you traveled 52.4 inches every time your cranks go all the way around. Gear Chart for 20" X 1.75" wheels Chainwheel   34   35    36   37   38    39   40   41    42   43    44   45   46    47   48     Rear 14    47.4 48.7 50.2 51.6 53.0 54.4 55.7 57.1 58.5 59.9 61.9 62.7 64.1 65.5 66.9      Rear 15    44.3 45.4 46    48.1 49.4 50.7 52.0 53.3 54.6 55.9 57.2 58.5 59.8 61.1 62.4     Rear 16    41.5 52.7 43.9 45.1 46.3 47.5 48.8 50.0 51.2 52.4 53.7 54.9 56.1 57.3 58.5     Rear 17    39.0 40.2 41.3 42.5 43.6 44.7 45.9 47.0 48.2 49.4 50.5 51.7 52.8 53.9 55.1     Rear 18    36.8 37.8 39.0 40.1 41.2 42.3 43.3 44.4 45.5 46.6 47.7 48.8 49.9 51.0 52.0 Gear Chart for 20" X 1.50" wheels Chainwheel    34  35   36    37    38   39   40     41  42    43   44   45   46    47    48     Rear 14    46.8 48.1 49.5 50.9 52.3 53.6  55    56.4 57.5 59.1 60.5 61.8 63.2 64.6 66.0     Rear 15    43.6 44.9 46.2 47.4 48.8 50.1  51.3 52.8 53.9 55.5 56.5 57.7 59.1 60.2 61.6     Rear 16    40.9 42.1 43.3 44.5 45.7 46.9  48.1 49.3 50.5 51.7 52.9 54.1 55.3 56.5 57.7     Rear 17    38.5 39.6 40.8 41.9 43.1 44.1  45.2 46.4 47.5 48.7 49.8 51.0 52.2 53.1 54.3     Rear 18    36.4 37.4 38.5 39.6 40.6 41.7  42.8 43.9 44.9 46.0 47.0 48.1 49.2 50.3 51.3 Gear Chart for 20" X 1.3/8" wheels   Chainwheel  34   35   36    37   38    39    40   41    42    43   44   45   46   47   48     Rear 14    51.0 52.5 54.0 55.5 57.0 58.5 60.0 61.5 63.0 64.5 66.0 67.5 69.0 70.5 72.0     Rear 15    47.6 49.0 50.4 51.6 53.2 54.6 56.0 57.4 58.8 60.2 61.6 63.0 64.4 65.8 67.2     Rear 16    44.6 45.9 47.3 48.6 49.9 51.2 52.5 53.9 55.2 56.5 57.8 59.1 60.4 61.7 63.0     Rear 17    42.0 43.2 44.5 45.7 47.0 48.2 49.4 50.7 51.9 53.2 54.4 55.6 56.9 58.1 59.3     Rear 18    39.7 40.7 42.0 43.2 44.4 45.5 46.7 47.9 49.0 50.2 51.4 52.5 53.7 54.9 56.0 Gear Chart for 20" X 1.1/8" wheels Chainwheel  34    35    36   37   38   39   40   41   42   43   44    45    46   47   48     Rear 14   48.6 50.0 51.4 52.8 54.3 55.7 57.1 58.6 60.0 61.4 62.8 64.3 65.7 67.1 68.6     Rear 15   45.3 46.7 48.0 49.3 50.7 52.0 53.3 54.7 56.0 57.3 58.7 60.0 61.3 62.7 64.0     Rear 16   42.5 43.8 45.0 46.2 47.5 48.7 50.0 51.2 52.5 53.7 55.0 56.2 57.5 58.7 60.0     Rear 17   40.0 41.2 42.3 43.5 44.7 45.9 47.0 48.2 49.4 50.6 51.8 52.9 54.1 55.3 56.5     Rear 18   37.7 38.8 40.0 41.1 42.2 43.3 44.4 45.6 46.7 47.8 48.9 50.0 51.1 52.2 53.3 Gear Chart for 24" X 1.75" wheels Chainwheel 34   35   36   37   38   39    40    41   42   43   44    45    46   47   48     Rear 14  58.3 60.0 61.7 63.3 65.0 66.9 68.6 70.3 72.0 73.7 75.3 77.0 78.9 80.6 82.3     Rear 15  54.4 56.0 57.6 59.3 60.7 62.4 64.1 65.5 67.2 68.9 70.3 72.0 73.7 75.1 76.8     Rear 16  51.0 52.5 54.0 55.5 57.0 58.5 60.0 61.4 63.1 64.5 66.0 67.4 69.1 70.5 72.0      Rear 17  48.0 49.4 50.0 52.2 53.6 55.1 56.5 57.9 59.3 60.7 62.1 63.6 65.0 66.2 67.7      Rear 18  45.3 46.5 48.0 49.4 50.7 52.0 53.3 54.7 56.0 57.3 58.5 60.0 61.4 62.6 64.1 Gear Chart for 24" X 1.50" wheels Chainwheel 34   35   36   37   38   39   40   41   42   43    44    45     46    47   48     Rear 14  55.9 57.5 59.1 60.7 62.3 64.2 65.8 67.4 69.0 70.6 72.2 73.8 75.7 77.3 78.9     Rear 15  52.1 53.7 55.2 56.7 58.2 59.8 61.3 62.8 64.4 65.9 67.4 69.0 70.6 72.0 73.6     Rear 16  48.4 50.3 51.8 53.2 54.6 56.0 57.5 58.9 60.3 61.8 63.2 64.6 66.2 67.6 69.0     Rear 17  46.0 47.3 48.7 50.0 51.4 52.8 54.1 55.5 56.8 58.8 59.5 60.8 62.3 63.5 64.8     Rear 18  43.4 44.7 46.0 47.2 48.5 49.8 51.1 52.4 53.7 54.9 56.2 57.5 58.9 60.0 61.4 Gear Chart for 24" X 1.3/8" wheels Chainwheel 34  35    36    37   38   39   40   41   42    43    44     45   46   47   48      Rear 14  58.3 60.0 61.7 63.3 65.0 66.9 68.6 70.3 72.0 73.7 75.3 77.0 78.9 80.6 82.3      Rear 15  54.4 56.0 57.6 59.3 60.7 62.4 64.1 65.5 67.2 68.9 71.3 72.0 73.7 75.1 76.8      Rear 16  51.1 52.5 54.0 55.5 57.0 58.5 60.0 61.4 63.1 64.5 66.0 67.4 69.1 70.5 72.0      Rear 17  48.0 49.4 50.8 52.2 53.6 55.1 56.5 57.9 59.3 60.7 62.1 63.3 65.0 66.2 67.7      Rear 18  45.3 46.5 48.0 49.4 50.7 52.0 53.3 54.7 56.0 57.3 58.5 60.0 61.4 62.6 64.1 Gear Chart for 24" X 1.1/8" wheels Chainwheel  34   35   36    37   38   39   40   41    42    43    44    45   46   47   48        Rear 14  54.9 56.5 58.1 59.7 61.3 63.1 64.7 66.3 67.9 69.4 71.0 72.6 74.4 76.0 77.6        Rear 15  51.3 52.8 54.3 55.8 57.3 58.8 60.3 61.8 63.3 64.9 66.3 67.9 69.4 70.8 72.4        Rear 16  48.1 49.5 50.9 52.3 53.7 55.1 56.6 57.9 59.5 60.8 62.2 63.9 65.1 66.5 67.9       Rear 17  45.2 46.6 47.9 49.3 50.6 51.9 53.2 54.6 55.9 57.2 58.6 59.9 61.3 62.4 63.8       Rear 18  42.7 43.9 45.2 46.6 47.7 49.1 50.3 51.5 52.8 54.0 55.3 56.6 57.9 59.0 60.4

Frame Sizing

Frame Size Chart Wondering what size Frame is right for you?  Check out the chart below and maybe it will help narrow down those decisions. Rider Height Frame Size Top Tube Length 4'0" & under Micro-Mini 15"-15.5" 4'0"-4'6" Mini 15.5"-16.5" 4'4"-4'10" Junior 16"-17.5" 4'8"-5'4" Expert 17"-18.5" 5'2"-5'8" Expert XL 18"-19" 5'6" - 5'10" Pro 18.5"-19.5" 5'10"-6'1" Pro XL 19"-21" 6' & over 6' & over 20.5" & over

Crank Length
	Crank Arm Length Chart Wondering what size Crank Arm is right for you?  Check out the chart below and maybe it will help narrow down those decisions. Rider Inseam Crank Arm Length 20" 140 mm 21" 145 mm 22" 150 mm 23" 155 mm 24" 160 mm 25" 162 mm 26" 166 mm 27" 171 mm 28" 175 mm 29" 177 mm 30" 180 mm 31" 182 mm 32" 185 mm 33" 185 mm 34" + 190 mm   information obtained from: roadrunnerbmx.org