|
Here is the technical information to determine
bike size and bike gearing
How Do You Know what Bike
Size You Should Ride?
Here is a chart to help guide you.
| BMX
RIDER BIKE SIZING |
|
Rider
Height
|
Frame
Size
|
Top Tube
Length
|
Stem
Length
|
Bar
Rise
|
Bar
Width
|
Crank
Length
|
Gearing
|
|
4'0" & under
|
Micro-Mini
|
15"- 15.5"
|
Mini
|
2"-2.5"
|
20"- 21.5"
|
See Chart
Below
|
See Chart
Below
|
|
4'0"-4'6"
|
Mini
|
15.5"- 16.5"
|
Mini
Mini XL
|
2"-3.5"
|
21"- 23"
|
See Chart
Below
|
See Chart
Below
|
|
4'4"-4'10"
|
Junior
|
16"- 17.5"
|
Mini
Mini XL
|
3"-4.5"
|
22"- 24.5"
|
See Chart
Below
|
See Chart
Below
|
|
4'8"-5'4"
|
Expert
|
17"- 18.5"
|
Pro
|
4.5"-6"
|
24"- 26"
|
See Chart
Below
|
See Chart
Below
|
|
5'2"-5'8"
|
Expert XL
|
18"-19"
|
Pro
|
6"-7.5"
|
26"- 27"
|
See Chart
Below
|
See Chart
Below
|
|
5'6" - 5'10"
|
Pro
|
18.5"- 19.5"
|
Pro
Pro XL
|
7"-8"
|
27"- 28"
|
See Chart
Below
|
See Chart
Below
|
|
5'10"-6'1"
|
Pro XL
|
19"-21"
|
Pro
Pro XL
|
7"-8"
|
17"- 28"
|
See Chart
Below
|
See Chart
Below
|
|
6' & over
|
Pro XXL
|
20.5" & over
|
Pro XL
Pro XXL
|
7"-8"
|
28"- ?"
|
See Chart
Below
|
See Chart
Below
|
What is the Correct Wheel
Size?
| Wheel
Sizes |
|
MAXIMUM RIDER WEIGHT
|
RIM WIDTH |
| 0 – 85# |
Sew Ups |
| 86 – 100 |
20 x 1-1/8" |
| 101 – 120 |
20 x 1-3/8" |
| 121 – 150 |
20 x 1.50" |
| 151 – 200 |
20 x 1.75" |
What Crank Size Do You Need?
| CRANK
SIZING CHART |
|
Riders Inseam
|
20"
|
21"
|
22"
|
23"
|
24"
|
25"
|
26"
|
|
Crank Length
|
140mm
|
145mm
|
150mm
|
155mm
|
160mm
|
162mm
|
166mm
|
| |
|
|
|
|
|
|
|
|
Riders Inseam
|
27"
|
28"
|
29"
|
30"
|
31"
|
32"
|
34"
|
| Crank
Length |
171mm
|
175mm
|
177mm
|
180mm
|
182mm
|
185mm
|
190mm
|
What Gear Should
You Run?
Most riders regardless of class seem to
prefer a rotation of approximately 53"
To figure your rotation here is the formula.
** Sprocket divided by Freewheel times Tire diameter **
Gear Charts
|
20"
X 1.75" Gear Chart
|
|
Sprocket
|
34
|
35
|
36
|
37
|
38
|
39
|
40
|
41
|
|
Freewheel 14
|
47.4
|
48.7
|
50.2
|
51.6
|
53.0
|
54.4
|
55.7
|
57.1
|
|
Freewheel 15
|
44.3
|
45.4
|
46.0
|
48.1
|
49.4
|
50.7
|
52.0
|
53.3
|
|
Freewheel 16
|
41.5
|
42.7
|
43.9
|
45.1
|
46.3
|
47.5
|
48.8
|
50.0
|
|
Freewheel 17
|
39.0
|
40.2
|
41.3
|
42.5
|
43.6
|
44.7
|
45.9
|
47.0
|
|
Freewheel 18
|
36.8
|
37.8
|
39.0
|
40.1
|
41.2
|
42.3
|
43.3
|
44.4
|
| |
|
|
Sprocket
|
42
|
43
|
44
|
45
|
46
|
47
|
48
|
|
|
Freewheel 14
|
58.5
|
59.9
|
61.9
|
62.7
|
64.1
|
65.5
|
66.9
|
|
Freewheel 15
|
54.6
|
55.9
|
57.2
|
58.5
|
59.8
|
61.1
|
62.4
|
|
Freewheel 16
|
51.2
|
52.4
|
53.7
|
54.9
|
56.1
|
57.3
|
58.5
|
|
Freewheel 17
|
48.2
|
49.4
|
50.5
|
51.7
|
52.8
|
53.9
|
55.1
|
|
Freewheel 18
|
45.5
|
46.6
|
47.7
|
48.8
|
49.9
|
51.0
|
52.0
|
|
20"
X 1.50" Gear Chart
|
|
Sprocket
|
34
|
35
|
36
|
37
|
38
|
39
|
40
|
41
|
|
Freewheel 14
|
46.8
|
48.1
|
49.5
|
50.9
|
52.3
|
53.6
|
55.0
|
56.4
|
|
Freewheel 15
|
43.6
|
44.9
|
46.2
|
47.4
|
48.8
|
50.1
|
51.3
|
52.8
|
|
Freewheel 16
|
40.9
|
42.1
|
43.3
|
44.5
|
45.7
|
46.9
|
48.1
|
49.3
|
|
Freewheel 17
|
38.5
|
39.6
|
40.8
|
41.9
|
43.1
|
44.1
|
45.2
|
46.4
|
|
Freewheel 18
|
36.4
|
37.4
|
38.5
|
39.6
|
40.6
|
41.7
|
42.8
|
43.9
|
| |
|
|
Sprocket
|
42
|
43
|
44
|
45
|
46
|
47
|
48
|
|
|
Freewheel 14
|
57.5
|
59.1
|
60.5
|
61.8
|
63.2
|
64.6
|
66.0
|
|
Freewheel 15
|
53.9
|
55.2
|
56.5
|
57.7
|
59.1
|
60.2
|
61.6
|
|
Freewheel 16
|
50.5
|
51.7
|
52.9
|
54.1
|
55.3
|
56.5
|
57.7
|
|
Freewheel 17
|
47.5
|
48.7
|
49.8
|
51.0
|
52.2
|
53.1
|
54.3
|
|
Freewheel 18
|
44.9
|
46.0
|
47.0
|
48.1
|
49.2
|
50.3
|
51.3
|
|
20"
X 1.3/8" Gear Chart
|
|
Sprocket
|
34
|
35
|
36
|
37
|
38
|
39
|
40
|
41
|
|
Freewheel 14
|
51.0
|
52.5
|
54.0
|
55.5
|
57.0
|
58.5
|
60.0
|
61.5
|
|
Freewheel 15
|
47.6
|
49.0
|
50.4
|
51.6
|
53.2
|
54.6
|
56.0
|
57.4
|
|
Freewheel 16
|
44.6
|
45.9
|
47.3
|
48.6
|
49.9
|
51.2
|
52.5
|
53.9
|
|
Freewheel 17
|
42.0
|
43.2
|
44.5
|
45.7
|
47.0
|
48.2
|
49.4
|
50.7
|
|
Freewheel 18
|
39.7
|
40.7
|
42.0
|
43.2
|
44.4
|
45.5
|
46.7
|
47.9
|
|
|
|
Sprocket
|
42
|
43
|
44
|
45
|
46
|
47
|
48
|
|
|
Freewheel 14
|
63.0
|
64.5
|
66.0
|
67.5
|
69.0
|
70.5
|
72.0
|
|
Freewheel 15
|
58.8
|
60.2
|
61.6
|
63.0
|
64.4
|
65.8
|
67.2
|
|
Freewheel 16
|
55.2
|
56.5
|
57.8
|
59.1
|
60.4
|
61.7
|
63.0
|
|
Freewheel 17
|
51.9
|
53.2
|
54.4
|
55.6
|
56.9
|
58.1
|
59.3
|
|
Freewheel 18
|
49.0
|
50.2
|
51.4
|
52.5
|
53.7
|
54.9
|
56.0
|
|
20"
X 1.1/8" Gear Chart
|
|
Sprocket
|
34 |
35 |
36 |
37 |
38 |
39 |
40 |
41 |
|
Freewheel 14
|
48.6
|
50.0
|
51.4
|
52.8
|
54.3
|
55.7
|
57.1
|
58.6
|
|
Freewheel 15
|
45.3
|
46.7
|
48.0
|
49.3
|
50.7
|
52.0
|
53.3
|
54.7
|
|
Freewheel 16
|
42.5
|
43.8
|
45.0
|
46.2
|
47.5
|
48.7
|
50.0
|
51.2
|
|
Freewheel 17
|
40.0
|
41.2
|
42.3
|
43.5
|
44.7
|
45.9
|
47.0
|
48.2
|
|
Freewheel 18
|
37.7
|
38.8
|
40.0
|
41.1
|
42.2
|
43.3
|
44.4
|
45.6
|
| |
|
|
Sprocket
|
42 |
43 |
44 |
45 |
46 |
47 |
48 |
|
|
Freewheel 14
|
60.0
|
61.4
|
62.8
|
64.3
|
65.7
|
67.1
|
68.6
|
|
Freewheel 15
|
56.0
|
57.3
|
58.7
|
60.0
|
61.3
|
62.7
|
64.0
|
|
Freewheel 16
|
52.5
|
53.7
|
55.0
|
56.2
|
57.5
|
58.7
|
60.0
|
|
Freewheel 17
|
49.4
|
50.6
|
51.8
|
52.9
|
54.1
|
55.3
|
56.5
|
|
Freewheel 18
|
46.7
|
47.8
|
48.9
|
50.0
|
51.1
|
52.2
|
53.3
|
|
24"
X 1.75" Gear Chart
|
|
|
Sprocket
|
34
|
35
|
36
|
37
|
38
|
39
|
40
|
41
|
|
Freewheel 14
|
58.3
|
60.0
|
61.7
|
63.3
|
65.0
|
66.9
|
68.6
|
70.3
|
|
Freewheel 15
|
54.4
|
56.0
|
57.6
|
59.3
|
60.7
|
62.4
|
64.1
|
65.5
|
|
Freewheel 16
|
51.0
|
52.5
|
54.0
|
55.5
|
57.0
|
58.5
|
60.0
|
61.4
|
|
Freewheel 17
|
48.0
|
49.4
|
50.0
|
52.2
|
53.6
|
55.1
|
56.5
|
57.9
|
|
Freewheel 18
|
45.3
|
46.5
|
48.0
|
49.4
|
50.7
|
52.0
|
53.3
|
54.7
|
| |
|
|
Sprocket
|
42
|
43
|
44
|
45
|
46
|
47
|
48
|
|
|
Freewheel 14
|
72.0
|
73.7
|
75.3
|
77.0
|
78.9
|
80.6
|
82.3
|
|
Freewheel 15
|
67.2
|
68.9
|
70.3
|
72.0
|
73.7
|
75.1
|
76.8
|
|
Freewheel 16
|
63.1
|
64.5
|
66.0
|
67.4
|
69.1
|
70.5
|
72.0
|
|
Freewheel 17
|
59.3
|
60.7
|
62.1
|
63.6
|
65.0
|
66.2
|
67.7
|
|
Freewheel 18
|
56.0
|
57.3
|
58.5
|
60.0
|
61.4
|
62.6
|
64.1
|
|
24"
X 1.50" Gear Chart
|
|
|
Sprocket
|
34
|
35
|
36
|
37
|
38
|
39
|
40
|
41
|
|
Freewheel 14
|
55.9
|
57.5
|
|