Since you can't always have a gear
chart by your side. It's important to know how to calulate your
gear ratio yourself. All you do is 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.
If your gear size is large 58 or greater, you will go faster, but
take off slower. It will take longer to reach top speed. Snapping
out of the gate, going uphill, powering out of turns, etc. will
be harder with a high gear. On the other hand, a low gear size of
55 or less will result in a better start, but lower overall speed.
How do I know what
size gears I should ride?
Use the chart below to help you decide
what size gears you should be riding.
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 1.50" 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 |
55.5 |
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 |
52.6 |
53.9 |
55.2 |
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 1.75" 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 |
61.3 |
62.7 |
64.1 |
65.5 |
66.9 |
| Rear 15 |
44.3 |
45.4 |
46.8 |
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 |
42.7 |
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 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 |
57.7 |
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 |
45.5 |
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 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 |
50.0 |
51.8 |
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 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 |
48.8 |
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 1.75" 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 |
50.8 |
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 1.1/8" 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 |
77.5 |
| 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 |
|
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 |
70.3 |
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 |
66.6 |
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 |
63.6 |
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 |
Is your bike set up properly?
Just like people are built different,
bikes are built different too. Use the sizing charts on this page
to help you make sure your bike is set up properly.
How do I know what size frame I should
ride?
Use the chart below to help you decide what size frame you should
be riding.
|
Frame
Sizing Chart
|
| Frame Size |
Micro - Mini |
Mini |
Junior |
Expert |
Expert XL |
Pro |
Pro XL |
Pro XXL |
| Top Tube Lenght |
15"-16" |
16"-17.5" |
17.5"-18.5" |
18.5"-20" |
19"-20" |
20"-20.5" |
20.5"-21" |
21"-22" |
| Riders Height |
4'0" & under |
4'0"-4'6" |
4'4"-4'10" |
4'8"-5'4" |
5'2"-5'8" |
5'6" - 5'10" |
5'10"-6' |
6' & over |
| Riders Weight |
40-65 lbs |
50-85 lbs |
60-100 lbs |
70-110 lbs |
75-125 lbs |
100 lbs & over |
140 lbs & over |
160 lbs & over |
How do I know what size wheels I should
ride?
Use the chart below to help you decide what size wheels you should
be riding.
|
Wheel
Sizing Chart
|
| Riders
Age |
Under 5 |
5 to 10 |
9 to 12 |
12 to 14 |
14 to 19 |
19 & up |
| Riders
Weight |
55lbs & below |
55-80lbs |
80-115lbs |
115-145lbs |
145-190lbs |
190lbs & up |
| Wheel Size |
18 x 1" |
20 x 1-1/8"
24 x 1-1/8" |
20 x 1-3/8"
24 x 1-3/8" |
20 x 1.50
24 x 1.50 |
20 x 1.75"
24 x 1.75" |
20 x 2.00"
24 x 2.00" |
|
It is recommended riders
who weigh 145lbs or more should run atleast a 20 x 1.75 tire
on the front wheel.
|
How do I know what
size cranks I should ride?
Use the chart below to help you decide
what size cranks you should be riding.
|
Crank
Sizing Chart
|
| Inseam |
up to 15" |
15" to 16" |
16" to 17" |
17" to 18" |
18"- 20" |
20" - 24" |
24" - 28" |
28" - 30" |
30" - 32" |
32" - 34" |
34" + |
| Crank
Length |
135
mm |
140
mm |
145
mm |
150
mm |
155
mm |
160
mm |
165
mm |
170
mm |
175
mm |
180
mm |
185
mm |
How do I know what
size stem I should ride?
Use the chart below to help you decide
what size stem you should be riding.
|
Stem Size
Chart
|
| Rider
Height |
4'0" & Under |
4'0" - 4'6" |
4'4" - 4'10" |
4'8" - 5'4" |
5'2" - 5'8" |
5'6" - 5'10" |
5'10" - 6'1" |
6' & Over |
| Stem Size
|
Mini |
Mini / Mini XL |
Mini/ Mini XL |
Pro |
Pro |
Pro / Pro XL |
Pro / Pro XL |
Pro XL / Pro XXL |
General bike information
if you plan on racing.
Any standard BMX bike will do. So before
you go investing $100's of dollars in a race bike, start off on what
you have or something low cost. If you decide you like it and want
to stay racing, then start looking or building that perfect race 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.
You can not have the following items
on your bike.
Reflectors -Freestyle Pegs - Kickstands - Chain Guards - Front Brakes
Rider requirements.
All riders must wear the following:
Helmet (preferably full-faced) with a working strap, no
snaps.
Pants.
Long sleeve shirt.
Enclosed shoes.
