need a math guy
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
I agree. That 2010 probably has a 68 tooth rear pully that makes the final drive ratio 2.968 not 2.790. And without knowing the tire may not be 25.2 in dia. My tire per Dunlop is 25.71 dia when new and these numbers put my calculation at 77.32 mph.
25.2" dia tire runs 75.78 mph.
25.2" dia tire runs 75.78 mph.
Road Master
Joined: Jun 2011
Posts: 974
Likes: 13
From: Chesapeake Virginia
Must have missread the question I thought he asked how fast HE would be going at 3000 rpm. Sorry!
Road Warrior
Joined: Nov 2008
Posts: 1,296
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From: Cheltenham, UK
If ever anyone asks me the difference between a mathematician and an engineer I will refer them to this thread :-)
Ultimate HDF Member
Joined: Dec 2009
Posts: 5,865
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From: Potsdam, NY
missing information: gear ratio, final drive ratio, rear wheel tire circumference or diam (to tire tread, not rim diam). Suggest finding a 7th grader to help solve this for you.
Road Master
Joined: Jun 2011
Posts: 974
Likes: 13
From: Chesapeake Virginia
From reading grbrowns other posts I beleive he is probably both and respect his opinions. I am neither but I did read the question differently.
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
hoggy05 asked for a math guy to give him the speed his bike is doing at 3,000rpm. As an engineer I use applied math and it was too tempting to give him the answer as a math equation! Iron Butt has correctly identified the tyre diameter and gear ratio.
It's the weekend after all, time for a little fun!
It's the weekend after all, time for a little fun!
Road Master
Joined: Jun 2011
Posts: 974
Likes: 13
From: Chesapeake Virginia
hoggy05 asked for a math guy to give him the speed his bike is doing at 3,000rpm. As an engineer I use applied math and it was too tempting to give him the answer as a math equation! Iron Butt has correctly identified the tyre diameter and gear ratio.
It's the weekend after all, time for a little fun!
It's the weekend after all, time for a little fun!
BTW it is raining here. No fun until 5:30 pm.
Road Warrior
Joined: Nov 2008
Posts: 1,296
Likes: 3
From: Cheltenham, UK
Now, as an engineer I was always trained to show my workings clearly and documented.....old habits die hard. Of course we could get on to tyre (not tire!!) pressure and the effect of running temperature on that pressure and the subsequent nominal changes in diameter. That could keep us busy all week and who knows, maybe the completely shocking weather in the UK will have cleared by then!
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Road Master
Joined: Jun 2011
Posts: 974
Likes: 13
From: Chesapeake Virginia
No dispute from my side, hence the smiley face...
Now, as an engineer I was always trained to show my workings clearly and documented.....old habits die hard. Of course we could get on to tyre (not tire!!) pressure and the effect of running temperature on that pressure and the subsequent nominal changes in diameter. That could keep us busy all week and who knows, maybe the completely shocking weather in the UK will have cleared by then!
Now, as an engineer I was always trained to show my workings clearly and documented.....old habits die hard. Of course we could get on to tyre (not tire!!) pressure and the effect of running temperature on that pressure and the subsequent nominal changes in diameter. That could keep us busy all week and who knows, maybe the completely shocking weather in the UK will have cleared by then!
