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SpikeC
Joined: 20 Aug 2013 Posts: 450 Location: Portland, Oregon
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Posted: Tue Jan 27, 2015 4:54 am Post subject: DB5R gearing question |
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Last year I was bombing along on a remote 2 lane in central Oregon (Backoven road). I saw 141 mph at one point, and several 136s at several times. At 136 my bike was turning around 7.5k rpm. what I was wondering is, if I added a tooth to the rear sprocket, could I gain more speed by letting the engine rev closer to the red line.
Now, of course this is all hypothetical, as I would never exceed the posted speed limit on any public roadway, but this is just a question of theoretical interest..... _________________ Spike C.
Portland, Oregon, USA
2008 Bimota DB5R
1965 Triumph T100SC |
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CNC
Joined: 19 Jul 2013 Posts: 257 Location: Slovenia
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Posted: Tue Jan 27, 2015 6:51 pm Post subject: |
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I think around 140 - 145 is realistic speed and with changed gearing you won't get a lot... DB5 gearing is already "short-ish"... Anyway, if you'll try, I'm quite interested what the results will be _________________ Bimota DB7, Bimota DB5 Mille, Ducati 916, Ducati M900, Benelli Tornado Tre |
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Tricolour
Joined: 07 Jul 2014 Posts: 18 Location: Australia
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Posted: Sat Feb 07, 2015 5:46 am Post subject: |
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The DB5R is rated at 98Hp (71.5 KW) at 7500 rpm and 105 Nm of torque at 5500 rpm. Nice torque figure but low kW's.
Looks like you can't get past your max kW output at 7500 rpm. Adding another tooth to the rear might free up a few revs or taking a tooth off might give you a few more MPH at that rpm?
Adding one tooth to the rear means you need another 200rpm to get back up to your original maximum speed and another 200rpm to increase your speed by 3.5mph. You are now at 7900rpm - I don't think you could do this.
Why not visit Gearcommander and factor in some changes.
Use Ducati 1100 Monster gearing as a base and change the figures to your gearing if the final drive gearing is too far out.
I have added my DB9 - you could add your DB5R.
Eddie. _________________ DB9S
Thruxton R
Moto Morini Corsaro |
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