BMW
Airhead Tools, Parts and Other Information
The
early /5, /6 & /7 BMW
forks were actually quite sophisticated. After all, BMW was the first
manufacturer to use a sliding fork front suspension.
There
are other web sites
that explain methods of alligning the two fork legs. This is important.
What
other things can be done
to hopefully improve the front suspension?
Springs
Oil
Damper changes
Fork Braces
Triple Clamp changes
Steering Damper
There
are many options when looking
at springs. Some are listed below.
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BMW Airhead Fork
Information |
2005 |
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BMW 36mm
Forks 1970- 1980 |
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/5,/6,/7
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Recommended |
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TYPE 1-C |
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Spring |
Spring Rates |
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Preload |
Fork oil |
Oil amount in
CCs |
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Make |
Model |
BMW Part # |
Free length |
Soft - Lbs |
Soft - Kg |
Hard - Lbs |
Hard - Kg |
Inch |
MM |
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Change |
Rebuild |
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BMW |
Early |
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530-542 mm |
18.48 |
0.33 |
26.88 |
0.48 |
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4W - 5W |
265 |
280 |
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BMW |
Late |
31 421 231 358 |
543 mm |
18.48 |
0.33 |
42.56 |
0.76 |
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4W - 5W |
235 |
250 |
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BMW |
HD |
31 421 232 017 |
567 mm |
26.32 |
0.47 |
41.44 |
0.74 |
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Works |
280X |
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127+381mm |
34 |
0.61 |
60 |
1.07 |
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Works |
280XH |
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127+381mm |
40 |
0.71 |
60 |
1.07 |
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Progressive |
11-1101 |
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35 |
0.63 |
45 |
0.80 |
0 |
0 |
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Race-Tech |
FRSP
S264380 |
425mm |
44.8 |
0.8 |
44.8 |
0.8 |
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Race-Tech |
FRSP
S264385 |
425mm |
47.6 |
0.85 |
47.6 |
0.85 |
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Race-Tech |
FRSP
S264390 |
425mm |
50.4 |
0.9 |
50.4 |
0.9 |
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Race-Tech
Emulator |
FEGV
S3301 |
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Must
make an adaptor |
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10W |
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Use
heavier springs |
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BMW Brembo
38mm All BMW '85 on EXCEPT (GS/PD/R/Mystic) |
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Recommended |
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TYPE 5-C |
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Spring |
Spring Rates |
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Preload |
Fork oil |
Oil amount in
CCs |
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Make |
Model |
BMW Part # |
Free length |
Soft - Lbs |
Soft - Kg |
Hard - Lbs |
Hard - Kg |
Inch |
MM |
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Change |
Rebuild |
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BMW |
Standard |
31 421 452 205 |
472-488 mm |
30.24 |
0.54 |
43.12 |
0.77 |
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4W - 5W |
320 |
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BMW |
HD |
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Works |
3100 |
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34.00 |
0.61 |
60.00 |
1.07 |
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Works |
3100H |
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40.00 |
0.71 |
60.00 |
1.07 |
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Progressive |
11-1130 |
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0 |
0 |
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Race-Tech |
FRSP
S293880 |
377mm |
44.8 |
0.8 |
44.8 |
0.8 |
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Race-Tech |
FRSP
S293885 |
377mm |
47.6 |
0.85 |
47.6 |
0.85 |
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Race-Tech |
FRSP
S293890 |
377mm |
50.4 |
0.9 |
50.4 |
0.9 |
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Race-Tech |
FRSP
S293895 |
377mm |
53.2 |
0.95 |
53.2 |
0.95 |
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Race-Tech
Emulator |
FEGV
3501 |
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Adaptor
required |
(29.0
x 21.3 x 15 tall) |
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