Gearbox & Speedo Ratio Calculator
Guessworks Feature Product - A+ 1275 Straight Cut Transfer Gears
Straight Cut 1:1 ratio +A 1275 transfer or drop gears.
These provide that ever so noticable whine you hear in some vehicles. Although technically a weaker design than the std Helical gears, the materials used in manufacture make these every bit as strong, if not stronger.
The reduced side load on the transfer case, and reduced transmission loss, make these the gears of choice for the performance Classic Mini engine.
more....... £ 215.00
Tyre Size
145 x 10
165/70 x 10
145/70 x 12
165/60 x 12
175/50 x 13
195/45 x 13
135 x 12
150/65 x R315
155/70 x 12
160/65 x 12
160/65 x R315
185/55 x 13
145 x 13
155 x 13
185/70 x 13
Drop Gear Ratio
1:1 (Standard)
0.9666:1 (30/29 A+ Eco Primary/Std Input)
0.9655:1 (29/28 A+ Std Primary/Eco Input)
0.9333:1 (30/28 A+ Eco Primary/Eco Input)
0.9580:1 (24/23)
1.0416:1 (24/25)
1.0435:1 (23/24)
1.0450:1 (22/23)
1.0869:1 (23/25)
1.0900:1 (22/24)
1.1364:1 (22/25)
Gearbox type
MKI Mini Pre '64 (Magic Wand)
MKI/II Mini Post '64 (Magic Wand)
MkI/II Cooper & MkI/II/III Cooper 'S'
MkI/II/III Cooper 'S' (Close Ratio / Straight Cut )
MkIII Cooper 'S' & 1275 GT (Close Ratio)
MKIII/IV Mini & Metro (pre A+ <'84)
MKV/VI/VII Mini, ERA Turbo & Metro (A+ >'84)
Metro 1.3 HLE (Double grove A+)
JKD (Abingdon ST ratios CR/SC)
Minispares (Clubman ratios CR/SC) C-STN39
Minispares (Abingdon ST ratios CR/SC) C-STN77
Minispares (Metro Challenge CR/SC) nla?
Minisport (Abingdon ST ratios CR/SC) GRBMS4014
TRAN-X (Abingdon ST ratios CR/SC)
TRAN-X (Clubman ratios CR/SC)
JKD Involute 4 speed Dog Kit (2.31:1 1st)
JKD Involute 4 speed Dog Kit (2.16:1 1st)
JKD Involute 4 speed Dog Kit (2.02:1 1st)
JKD Involute 4 speed Dog Kit (1.75:1 1st)
MED 4 speed Dog Kit
Quaife 4 speed Dog Kit (2.3:1 1st)
Quaife 4 speed Dog Kit (2.1:1 1st)
Quaife/Swiftune 4 speed Dog Kit (US Spec 1.692:1 1st)
JKD Involute 5 speed Dog Kit
KAD 5 speed Dog Kit
Minispares 5 speed Helical Gearset
Minispares 5 speed SCCR Gearset
JKD 6 speed Dog Box
Final Drive Ratio
2.760:1 21/58
2.950:1 20/59 ( Metro 1.3 HLE '85 on )
3.105:1 19/59 ( Metro 1.0 HLE & Some 1.3 HLE's )
3.211:1 19/61 ( MG Metro Turbo )
3.444:1 18/62 ( Most Mini's & post '84 Metro's )
3.647:1 17/62 ( Metro City, L & Van )
3.765:1 17/64 ( MKI Mini, 850's and Vans)
3.939:1 16/63 ( Option on Cooper "S" MKI/II/III )
4.133:1 15/62 ( Option on Cooper "S" MKI/II/III )
4.267:1 15/64 ( Option on Cooper "S" MKI/II/III )
4.350:1 15/65 ( Option on Cooper "S" MKI/II/III )
4.307:1 13/56 ( Special )
TPM of Speedo
1408 - 90mph Smiths central (unknown source)
1376 - 90mph Smiths central (850)
1312 - 90mph Smiths Early tri'clock
1300 - Late Cooper 110mph Nippon Seiki
1280 - 90mph Smiths central Pre 84'
1248 - 100mph Smiths (Austin 1300GT)
1248 - 120mph Smiths (1275 GT/25/1100 Special)
1242 - 90mph Nippon Seike
1216 - 90mph Smiths post '84
1120 - unknown speedo
1000 - unknown speedo
Worm & Pinion ratio
7/15
7/16
7/17
7/18
6/16
6/17
6/18
5/16
5/17
5/18
Calculated Speed by RPM in each Gear
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8000
RPM
Actual Speed vs (Speedo Reading)
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