With Assessment |
Planetary Gearset: Teeth[a] |
Count |
Total[b] Center[c] |
Avg.[d] |
|
Model Type |
Version |
S1[e] R1[f] |
S2[g] R2[h] |
S3[i] R3[j] |
S4[k] R4[l] |
Brakes Clutches |
Ratio Span |
Gear Step[m] |
Gear Ratio |
R
 |
1
 |
2
 |
3
 |
4
 |
5
 |
6
 |
7
 |
8
 |
Step[m] |
[n] |
 |
[o] |
 |
 |
 |
 |
 |
 |
Δ Step[p][q] |
|
|
 |
 |
 |
 |
 |
 |
|
Shaft Speed |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Δ Shaft Speed[r] |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
2008: Pilot Series |
8HP 70[s] |
700 N⋅m (516 lb⋅ft) |
48[14] 96 |
48[14] 96 |
69[5] 111 |
23[5] 85 |
2 3 |
7.0435 1.7693 |
1.3216[m] |
Gear Ratio |
−3.2968[n]
 |
4.6957
 |
3.1304[q]
 |
2.1039
 |
1.6667[m][q][r]
 |
1.2845[q]
 |
1.0000
 |
0.8392[q][r]
 |
0.6667
 |
Step |
0.7021[n] |
1.0000 |
1.5000 |
1.4879 |
1.2623[m] |
1.2975 |
1.2845 |
1.1917 |
1.2587 |
Δ Step[p] |
|
|
1.0081[q] |
1.1787 |
0.9729[q] |
1.0101[q] |
1.0779 |
0.9467[q] |
|
Speed |
-1.4243 |
1.0000 |
1.5000 |
2.2319 |
2.8174 |
3.6555 |
4.6957 |
5.5957 |
7.0435 |
Δ Speed |
1.4243 |
1.0000 |
0.5000 |
0.7319 |
0.5855[r] |
0.8382 |
1.0401 |
0.9000[r] |
1.4478 |
2010: 1st Generation |
HP 30/I 8HP 45 |
300 N⋅m (221 lb⋅ft) 450 N⋅m (332 lb⋅ft) |
48 96 |
48 96 |
60 96 |
28 104 |
2 3 |
7.0714 1.7728 |
1.3224[m] |
Gear Ratio |
−3.2952[n]
 |
4.7143
 |
3.1429[q]
 |
2.1064
 |
1.6667[m][q][r]
 |
1.2854[q]
 |
1.0000
 |
0.8387[q][r]
 |
0.6667
 |
Step |
0.6990[n] |
1.0000 |
1.5000 |
1.4921 |
1.2638[m] |
1.2966 |
1.2854 |
1.1923 |
1.2581 |
Δ Step[p] |
|
|
1.0053[q] |
1.1805 |
0.9747[q] |
1.0087[q] |
1.0781 |
0.9477[q] |
|
Speed |
-1.4306 |
1.0000 |
1.5000 |
2.2381 |
2.8286 |
3.6576 |
4.7143 |
5.6209 |
7.0714 |
Δ Speed |
1.4306 |
1.0000 |
0.5000 |
0.7381 |
0.5905[r] |
0.8390 |
1.0467 |
0.9066[r] |
1.45058 |
|
8HP 55 8HP 65 8HP 70 8HP 90 |
650 N⋅m (479 lb⋅ft) 650 N⋅m (479 lb⋅ft) 700 N⋅m (516 lb⋅ft) 900 N⋅m (664 lb⋅ft) |
48 [14][15] 96 |
48 [14][15] 96 |
69 111 |
28 104 |
2 3 |
7.0714 1.7728 |
1.3224[m] |
Gear Ratio |
−3.3168[n]
 |
4.7143
 |
3.1429[q]
 |
2.1064
 |
1.6667[m][q][r]
 |
1.2847[q]
 |
1.0000
 |
0.8392[q][r]
 |
0.6667
 |
Step |
0.7036[n] |
1.0000 |
1.5000 |
1.4921 |
1.2638[m] |
1.2973 |
1.2847 |
1.1917 |
1.2587 |
Δ Step[p] |
|
|
1.0053[q] |
1.1806 |
0.9742[q] |
1.0098[q] |
1.0781 |
0.9467[q] |
|
Speed |
-1.4213 |
1.0000 |
1.5000 |
2.2381 |
2.8286 |
3.6696 |
4.7143 |
5.6179 |
7.0714 |
Δ Speed |
1.4243 |
1.0000 |
0.5000 |
0.7381 |
0.5905[r] |
0.8410 |
1.0447 |
0.9036[r] |
1.4536 |
2014: 2nd Generation |
8HP 75/I[16] |
740 N⋅m (546 lb⋅ft) |
48 96 |
48 96 |
69 111 |
28 104 |
2 3 |
7.0714 1.7728 |
1.3224[m] |
Ratio |
−3.3168[n] |
4.7143 |
3.1429[q] |
2.1064 |
1.6667[m][q][r] |
1.2847[q] |
1.0000 |
0.8392[q][r] |
0.6667 |
|
8HP 30/II[16] 8HP 50[16] |
300 N⋅m (221 lb⋅ft) 500 N⋅m (369 lb⋅ft) |
48 96 |
54 96 |
60 96 |
24 96 |
2 3 |
7.8125 1.7889 |
1.3413[m] |
Gear Ratio |
−3.4560[n]
 |
5.0000
 |
3.2000[q]
 |
2.1429
 |
1.7200[m][q][r]
 |
1.3139[q]
 |
1.0000
 |
0.8221[q][r]
 |
0.6400
 |
Step |
0.6912[n] |
1.0000 |
1.5625 |
1.4933 |
1.2458[m] |
1.3091 |
1.3139 |
1.2163 |
1.2846 |
Δ Step[p] |
|
|
1.0463[q] |
1.1986 |
0.9517[q] |
0.9964[q] |
1.0802 |
0.9469[q] |
|
Speed |
-1.4468 |
1.0000 |
1.5625 |
2.3333 |
2.9070 |
3.8056 |
5.0000 |
6.0817 |
7.8125 |
Δ Speed |
1.4468 |
1.0000 |
0.5625 |
0.7708 |
0.5736[r] |
0.8986 |
1.1944 |
1.0817[r] |
1.7308 |
|
8HP 75/II[16] 8HP 95[t] |
740 N⋅m (546 lb⋅ft) 900 N⋅m (664 lb⋅ft) |
48 96 |
54 96 |
69 111 |
24 96 |
2 3 |
7.8125 1.7889 |
1.3413[m] |
Gear Ratio |
−3.4783[n]
 |
5.0000
 |
3.2000[q]
 |
2.1429
 |
1.7200[m][q][r]
 |
1.3131[q]
 |
1.0000
 |
0.8226[q][r]
 |
0.6400
 |
Step |
0.6957[n] |
1.0000 |
1.5625 |
1.4933 |
1.2458[m] |
1.3099 |
1.3131 |
1.2156 |
1.2853 |
Δ Step[p] |
|
|
1.0463[q] |
1.1986 |
0.9511[q] |
0.9975[q] |
1.0802 |
0.9458[q] |
|
Speed |
-1.4375 |
1.0000 |
1.5625 |
2.3333 |
2.9070 |
3.8078 |
5.0000 |
6.0781 |
7.8125 |
Δ Speed |
1.4375 |
1.0000 |
0.5625 |
0.7708 |
0.5736[r] |
0.9008 |
1.1922 |
1.0781[r] |
1.7344 |
2018: 3rd Generation |
8HP 76/I[u] |
760 N⋅m (561 lb⋅ft) |
48 96 |
54 96 |
69 111 |
24 96 |
2 3 |
7.8125 1.7889 |
1.3413[m] |
Ratio |
−3.4783[n] |
5.0000 |
3.2000[q] |
2.1429 |
1.7200[m][q][r] |
1.3131[q] |
1.0000 |
0.8226[q][r] |
0.6400 |
|
8HP 30/III[v] 8HP 51[w] |
300 N⋅m (221 lb⋅ft) 500 N⋅m (369 lb⋅ft) |
48 96 |
54 96 |
60 96 |
24 102 |
2 3 |
8.2031 1.8330 |
1.3507[m] |
Gear Ratio |
−3.7120[n]
 |
5.2500
 |
3.3600[q]
 |
2.1724
 |
1.7200[m][q][r]
 |
1.3161[q]
 |
1.0000
 |
0.8221[q][r]
 |
0.6400
 |
Step |
0.7070[n] |
1.0000 |
1.5625 |
1.5467 |
1.2630[m] |
1.3069 |
1.3161 |
1.2163 |
1.2846 |
Δ Step[p] |
|
|
1.0102[q] |
1.2246 |
0.9664[q] |
0.9931[q] |
1.0820 |
0.9469[q] |
|
Speed |
-1.4143 |
1.0000 |
1.5625 |
2.4167 |
3.0523 |
3.9892 |
5.2500 |
6.3858 |
8.2031 |
Δ Speed |
1.4143 |
1.0000 |
0.5625 |
0.8542 |
0.6357[r] |
0.9369 |
1.2608 |
1.1358[r] |
1.8173 |
|
8HP 76/II[x] |
760 N⋅m (561 lb⋅ft) |
48 96 |
54 96 |
69 111 |
24 108 |
2 3 |
8.5938 1.8762 |
1.3597[m] |
Gear Ratio |
−3.9930[n]
 |
5.5000
 |
3.5200[q]
 |
2.2000
 |
1.7200[m][q][r]
 |
1.3172[q]
 |
1.0000
 |
0.8226[q][r]
 |
0.6400
 |
Step |
0.7260[n] |
1.0000 |
1.5625 |
1.6000 |
1.2791[m] |
1.3058 |
1.3172 |
1.2156 |
1.2853 |
Δ Step[p] |
|
|
0.9766[q] |
1.2509 |
0.9796[q] |
0.9913[q] |
1.0836 |
0.9458[q] |
|
Speed |
-1.3774 |
1.0000 |
1.5625 |
2.5000 |
3.1977 |
4.1754 |
5.5000 |
6.6859 |
8.5938 |
Δ Speed |
1.3774 |
1.0000 |
0.5625 |
0.9375 |
0.6977[r] |
0.9777 |
1.3246 |
1.1859[r] |
1.8321 |
2022: 4th Generation |
8HP 100[y] |
1,000 N⋅m (738 lb⋅ft) [10] |
48 96 |
54 96 |
60 108 |
24 96 |
2 3 |
7.8125 1.7889 |
1.3413[m] |
Gear Ratio |
−3.9680[n]
 |
5.0000
 |
3.2000[q]
 |
2.1429
 |
1.7200[m][q][r]
 |
1.2973[q]
 |
1.0000
 |
0.8327[q][r]
 |
0.6400
 |
Step |
0.7936[n] |
1.0000 |
1.5625 |
1.4933 |
1.2458[m] |
1.3259 |
1.2973 |
1.2009 |
1.3011 |
Δ Step[p] |
|
|
1.0463[q] |
1.1986 |
0.9397[q] |
1.0220[q] |
1.0803 |
0.9230[q] |
|
Speed |
-1.2601 |
1.0000 |
1.5625 |
2.3333 |
2.9070 |
3.8542 |
5.0000 |
6.0045 |
7.8125 |
Δ Speed |
1.2601 |
1.0000 |
0.5625 |
0.7708 |
0.5736[r] |
0.9473 |
1.1458 |
1.0045[r] |
1.8080 |
|
8HP 80[z] |
800 N⋅m (590 lb⋅ft) [10] |
48 96 |
54 96 |
60 108 |
24 108 |
2 3 |
8.5938 1.8762 |
1.3597[m] |
Gear Ratio |
−4.5440[n]
 |
5.5000
 |
3.5200[q]
 |
2.2000
 |
1.7200[m][q][r]
 |
1.3010[q]
 |
1.0000
 |
0.8327[q][r]
 |
0.6400
 |
Step |
0.8262[n] |
1.0000 |
1.5625 |
1.6000 |
1.2791[m] |
1.3221 |
1.3010 |
1.2009 |
1.3011 |
Δ Step[p] |
|
|
0.9766[q] |
1.2509 |
0.9675[q] |
1.0162[q] |
1.0834 |
0.9230[q] |
|
Speed |
-1.2104 |
1.0000 |
1.5625 |
2.5000 |
3.1977 |
4.2275 |
5.5000 |
6.6049 |
8.5938 |
Δ Speed |
1.2104 |
1.0000 |
0.5625 |
0.9375 |
0.6977[r] |
1.0298 |
1.2725 |
1.1049[r] |
1.9888 |
2016: Racing Cars |
8P 45R[aa] |
450 N⋅m (332 lb⋅ft) up to 1,050 N⋅m (774 lb⋅ft)[28] |
TBD |
TBD |
60 96 |
TBD |
2 3 |
4.2000 TBD |
1.2275[m] |
Ratio |
TBD |
TBD |
TBD |
TBD |
TBD |
TBD |
1.0000 |
TBD |
TBD |
2017: Commercial Vehicles[ab] |
8AP 600 T[ac] 8AP 800 T 8AP 1000 T 8AP 1200 T |
600 N⋅m (443 lb⋅ft) 800 N⋅m (590 lb⋅ft) 1,000 N⋅m (738 lb⋅ft) 1,200 N⋅m (885 lb⋅ft)[ad] |
65[ae] 115 |
65[ae] 115 |
62 122 |
27 105 |
2 3 |
7.6522 1.7673 |
1.3374[m] |
Gear Ratio |
−4.2501[n]
 |
4.8889
 |
3.1235[q]
 |
2.0334
 |
1.6389[m][q][r]
 |
1.2541[q]
 |
1.0000
 |
0.8400[q][r]
 |
0.6389
 |
Step |
0.8693[n] |
1.0000 |
1.5652 |
1.5361 |
1.2407[m] |
1.3068 |
1.2541 |
1.1905 |
1.3148 |
Δ Step[p] |
|
|
1.0190[q] |
1.2381 |
0.9494[q] |
1.0420[q] |
1.0535 |
0.9054[q] |
|
Speed |
-1.1503 |
1.0000 |
1.5652 |
2.4043 |
2.9831 |
3.8983 |
4.8889 |
5.8200 |
7.6522 |
Δ Speed |
1.1503 |
1.0000 |
0.5652 |
0.8391 |
0.5787[r] |
0.9153 |
0.9906 |
0.9311[r] |
1.8322 |
|
8AP 1200 S [af] |
1,200 N⋅m (885 lb⋅ft)[ad] |
65[ae] 115 |
65[ae] 115 |
65[ae] 115 |
27 105 |
2 3 |
7.6522 1.7673 |
1.3374[m] |
Gear Ratio |
−3.7569[n]
 |
4.8889
 |
3.1235[q]
 |
2.0334
 |
1.6389[m][q][r]
 |
1.2676[q]
 |
1.0000
 |
0.8305[q][r]
 |
0.6389
 |
Step |
0.7685[n] |
1.0000 |
1.5652 |
1.5361 |
1.2407[m] |
1.2929 |
1.2676 |
1.2041 |
1.2999 |
Δ Step[p] |
|
|
1.0190[q] |
1.2381 |
0.9596[q] |
1.0200[q] |
1.0527 |
0.9263[q] |
|
Speed |
-1.3013 |
1.0000 |
1.5652 |
2.4043 |
2.9831 |
3.8568 |
4.8889 |
5.8867 |
7.6522 |
Δ Speed |
1.3013 |
1.0000 |
0.5652 |
0.8391 |
0.5787[r] |
0.8738 |
1.0321 |
0.9979[r] |
1.7654 |
|
Ratio R & Even |
 |
 |
 |
 |
 |
Ratio Odd |
 |
 |
 |
 |
Algebra And Actuated Shift Elements[ag] |
Brake A[ah] |
❶ |
❶ |
❶ |
|
|
|
|
❶ |
❶ |
Brake B[ai] |
❶ |
❶ |
❶ |
❶ |
❶ |
❶ |
|
|
|
Clutch C[aj] |
|
❶ |
|
❶ |
|
❶ |
❶ |
❶ |
|
Clutch D[ak] |
❶ |
|
|
|
❶ |
❶ |
❶ |
❶ |
❶ |
Clutch E[al] |
|
|
❶ |
❶ |
❶ |
|
❶ |
|
❶ |
|
Layout
- Input and output are on opposite sides
- Planetary gearset 1 is on the input (turbine) side
- Input shafts are C2 and, if actuated, R3 and S4
- Output shaft is C4 (planetary gear carrier of gearset 4)
Total Ratio Span (Total Ratio Spread · Total Gear Ratio)

- A wider span enables the
- downspeeding when driving outside the city limits
- increase the climbing ability
- when driving over mountain passes or off-road
- or when towing a trailer
Ratio Span's Center

- The center indicates the speed level of the transmission
- Together with the final drive ratio
- it gives the shaft speed level of the vehicle
Average Gear Step

- With decreasing step width
- the gears connect better to each other
- shifting comfort increases
Sun 1: sun gear of gearset 1
Ring 1: ring gear of gearset 1
Sun 2: sun gear of gearset 2
Ring 2: ring gear of gearset 2
Sun 3: sun gear of gearset 3
Ring 3: ring gear of gearset 3
Sun 4: sun gear of gearset 4
Ring 4: ring gear of gearset 4
Standard 50:50 — 50 % Is Above And 50 % Is Below The Average Gear Step —
- With steadily decreasing gear steps (yellow highlighted line Step)
- and a particularly large step from 1st to 2nd gear
- the lower half of the gear steps (between the small gears; rounded down, here the first 3) is always larger
- and the upper half of the gear steps (between the large gears; rounded up, here the last 4) is always smaller
- than the average gear step (cell highlighted yellow two rows above on the far right)
- lower half: smaller gear steps are a waste of possible ratios (red bold)
- upper half: larger gear steps are unsatisfactory (red bold)
Standard R:1 — Reverse And 1st Gear Have The Same Ratio —
- The ideal reverse gear has the same transmission ratio as 1st gear
- no impairment when maneuvering
- especially when towing a trailer
- a torque converter can only partially compensate for this deficiency
- Plus 11.11 % minus 10 % compared to 1st gear is good
- Plus 25 % minus 20 % is acceptable (red)
- Above this is unsatisfactory (bold)
Standard 1:2 — Gear Step 1st To 2nd Gear As Small As Possible —
- With continuously decreasing gear steps (yellow marked line Step)
- the largest gear step is the one from 1st to 2nd gear, which
- for a good speed connection and
- a smooth gear shift
- must be as small as possible
- A gear ratio of up to 1.6667:1 (5:3) is good
- Up to 1.7500:1 (7:4) is acceptable (red)
- Above is unsatisfactory (bold)
From large to small gears (from right to left)
Standard STEP — From Large To Small Gears: Steady And Progressive Increase In Gear Steps —
- Gear steps should
- increase: Δ Step (first green highlighted line Δ Step) is always greater than 1
- As progressive as possible: Δ Step is always greater than the previous step
- Not progressively increasing is acceptable (red)
- Not increasing is unsatisfactory (bold)
Standard SPEED — From Small To Large Gears: Steady Increase In Shaft Speed Difference —
- Shaft speed differences should
- increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one
- 1 difference smaller than the previous one is acceptable (red)
- 2 consecutive ones are a waste of possible ratios (bold)
without generation designation
Der neue BMW M760 Li xDrive · BMW Medieninformation Deutschland (The new BMW M760 Li xDrive · BMW Media Information Germany) · 02/2016 · p. 23 · and Der neue BMW M760 Li xDrive · Technische Daten · BMW Medieninformation Oesterreich (The new BMW M760 Li xDrive · Technical Specifications · BMW Media Information Austria) · 01/2017 · p. 2 · 800 N⋅m (590 lb⋅ft)[17][16]
narrow total ratio span · preferebly for petrol engines, sports cars, and high performance engines · Alpina B3 Saloon AWD · Technical Data · 730 N⋅m (538 lb⋅ft)[18][16]
Technical specifications · The new BMW 3 Series Sedan · BMW Media Information · 03/2019 · p. 2: BMW 320i Sedan · 300 N⋅m (221 lb⋅ft)[19][16]
wide total ratio span · preferebly for Diesel engines, offroad cars, and low performance engines · loc. cit. · p. 18: BMW 330d Sedan · 580 N⋅m (428 lb⋅ft)[19][16] and Alpina D3 S Saloon AWD · Technical Data · 730 N⋅m (538 lb⋅ft)[20]
narrow total ratio span · preferebly for petrol engines, sports cars, and high performance engines · The first-ever BMW XM · Market launch September 2022[21][22] The all-new BMW M5 · Market launch June 2024[23][24]
wide total ratio span · preferebly for Diesel engines, offroad cars, and low performance engines · Progress and efficiency with added variety: additional drive system variants and innovations for the new BMW 7 Series · Market launch 2022/2023[25][26] Alpina XB7 AWD · Technical Data[27]
w/o hydraulic torque converter · narrow total ratio span of 4.2[28]
based on the same gearset concept as the 8HP transmissions[29][30]
Automatic Powershift Transmission for Trucks[31]
higher torque on demand[32]
Automatic Powershift Transmission for Special vehicles[33][34]
Permanently coupled elements
- S1 and S2
- C1 (carrier 1) and R4
- R2 and S3
- R3 and S4
Couples R3 and S4 with the turbine
Couples C3 (carrier 1) with C4 (carrier 4)
Couples R2 and S3 with R3 and S4
|
|