Dyna top speed and wobble.
Cruiser
Joined: Jun 2014
Posts: 234
Likes: 45
From: Spain
Ummm, you realize that "HP" is a reflection of torque thru the RPM band, right?
This explains why HD's horsepower levels are so pathetic as compared to other motorcycles (even twins.) It's because HD engines only rev 1/3 to 1/2 of what other engines do. The rate of torque is fine, but when measured thru only 4200 rpm, you get dismal HP levels. (This is for stock HD's btw.) Modded HD's don't count, as they're modded.
This explains why HD's horsepower levels are so pathetic as compared to other motorcycles (even twins.) It's because HD engines only rev 1/3 to 1/2 of what other engines do. The rate of torque is fine, but when measured thru only 4200 rpm, you get dismal HP levels. (This is for stock HD's btw.) Modded HD's don't count, as they're modded.
Last edited by Lambda; Feb 19, 2020 at 11:38 AM.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,925
Likes: 8,027
From: poway
Max is right, when it comes down to high speed, more torque would allow you to reach the max speed faster, but power is power, you need power to overcome the wind resistance (along with other factors), you have two roads to high speed, either increase the power or decrease the aerodynamic drag, you can always manipulate the torque at the wheels, but not the power.
Cruiser
Joined: Jun 2014
Posts: 234
Likes: 45
From: Spain
While thanks for the agreement, I'll have to disagree with you. It's still HP that is king. Especially getting it to the ground. Now if you are doing roll-ons in one gear, the motor that makes the most HP over the RPM range will likely come out ahead. In that case you are really matching torque at the same RPM range. Since RPM is matched (assuming the same gearing/bikes other than motor), it is really HP versus HP.
The statement where I was claiming that more torque makes you accelerate faster could be misleading in the context I wanted to use it, at the end of the day power is what matters.
Seasoned HDF Member
Joined: Jan 2015
Posts: 16,013
Likes: 7,139
From: Sandy Eggo's North County
Absolutely but as soon as you combine TQ with RPM, you have HP..
You can get 150 fp out of a big torque wrench but you won't be cranking out any HP.
Not sure what you are saying in the second section. HP is a product of TQ and RPM. If you make 150 fp at 2400 you won't be going as fast top speed compared to a guy making 150 fp at 4800 for sure since the resulting HP is different.
The point you seem be missing is that you will go faster if you gear properly on a motor that make say 100 fp at 4800 even tho it make 150 fp at 2400 because it makes more power at 4800. Assuming correct gearing.
You can get 150 fp out of a big torque wrench but you won't be cranking out any HP.
Not sure what you are saying in the second section. HP is a product of TQ and RPM. If you make 150 fp at 2400 you won't be going as fast top speed compared to a guy making 150 fp at 4800 for sure since the resulting HP is different.
The point you seem be missing is that you will go faster if you gear properly on a motor that make say 100 fp at 4800 even tho it make 150 fp at 2400 because it makes more power at 4800. Assuming correct gearing.
I think I see our miscommunication. You're talking rate of acceleration, and I'm talking about "achieving a top speed."
I thought the OP was wanting info on "top speed."
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,925
Likes: 8,027
From: poway
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,925
Likes: 8,027
From: poway
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