NOTE: These numbers may not be completely accurate, but they do reflect my current knowledge about how spinners work.

X axis: spinner's direction when you started moving
Y axis: number of frames since spinner last moved
Value:  probability of spinner facing down after 8 frames (1 bike step)

Only even frame counts are given because spinners update every 2 frames.

EDIT: It seems that the tick difference is actually 5, and not 4 = 8 / 2. Maybe has something to do with stopping and starting movement?

	| down	| up	| left	| right
------------------------------------------
0	| 0.731	| 0.070	| 0.070	| 0.128
2	| 0.723	| 0.073	| 0.073	| 0.132
4	| 0.714	| 0.075	| 0.075	| 0.136
6	| 0.704	| 0.078	| 0.078	| 0.141
8	| 0.693	| 0.080	| 0.080	| 0.146
10	| 0.682	| 0.083	| 0.083	| 0.152
12	| 0.669	| 0.087	| 0.087	| 0.157
14	| 0.656	| 0.090	| 0.090	| 0.164
16	| 0.642	| 0.094	| 0.094	| 0.171
18	| 0.626	| 0.098	| 0.098	| 0.178
20	| 0.609	| 0.102	| 0.102	| 0.186
22	| 0.591	| 0.107	| 0.107	| 0.195
24	| 0.570	| 0.113	| 0.113	| 0.205
26	| 0.548	| 0.118	| 0.118	| 0.215
28	| 0.523	| 0.125	| 0.125	| 0.227
30	| 0.495	| 0.132	| 0.132	| 0.241
32	| 0.463	| 0.141	| 0.141	| 0.256
34	| 0.427	| 0.150	| 0.150	| 0.273
36	| 0.386	| 0.161	| 0.161	| 0.292
38	| 0.339	| 0.173	| 0.173	| 0.315
40	| 0.284	| 0.187	| 0.187	| 0.341
42	| 0.219	| 0.205	| 0.205	| 0.372
44	| 0.141	| 0.225	| 0.225	| 0.409
46	| 0.156	| 0.222	| 0.222	| 0.399
48	| 0.174	| 0.219	| 0.219	| 0.388
50	| 0.196	| 0.214	| 0.214	| 0.375
52	| 0.223	| 0.208	| 0.208	| 0.360
54	| 0.258	| 0.200	| 0.200	| 0.342
56	| 0.309	| 0.188	| 0.188	| 0.316
58	| 0.389	| 0.167	| 0.167	| 0.278
60	| 0.544	| 0.125	| 0.125	| 0.206
62	| 1.000	| 0.000	| 0.000	| 0.000