What is the difference between brake and rear wheel horsepower?

[FloydV]

The term brake horsepower makes no sense to me. So, what does it refer to? I've also heard the definition that torque is the amount of work that can be done, and horsepower is how fast it can be done. Is that correct?

Floyd

 

[pashnit]

Horsepower gets measured at the crank, then it gets measure at the rear wheel. So ya gots two numbers.

 

[Tufbusa]

Horsepower gets measured at the crank, then it gets measure at the rear wheel. So ya gots two numbers.

That's partially correct Tim.

Brake Horse Power is ALWAYS measured at the crank with a brake dyno. Although manufacturers don't use this terminology in their press material, claimed power is almost always brake HP measured at the crank.

A rear wheel dyno like all of our tuners use can show significantly lower numbers then brake HP at the crank due to the HP lost in the drive train.

Horse Power is a measure of power and there are several different definitions depending on what part of the world you may be in when you ask the question.

 

[Lamb busa]

Lamb was also interested in this question

Horsepower explained

 

[dadofthree]

As always, what Lamb posted.


Tuf you did good brother

 

[frisbee]

I just know that I want MORE

 

[Fastfrog007]

I just know that I want MORE

Ain't that always the way brother

 

[ZRXMAX]

I just know that I want MORE

Their will come a point you have enough if you spend enough money with the people that put it together and tune it. Those longer swing arms take some of the fun out of having more power

 

[RYC1966]

Not that it matters much but an ideal tune for a given time of year is what matters...the drag cars with jets (in the carb) swap them during the day for a better run (not always the case)...some big hp nitro cars can't really get a hp value on a eng / chassis dyno. It would be interesting how detailed the f1 chassis / engine dynos are...avoiding a meltdown is the benefit of a chassis dyno...yet with that is in the hands of the tuner

 

[GNBRETT]

Those longer swing arms take some of the fun out of having more power

no they dont. makn 400+ hp and goin str8 and keepn the front end down is whats fun.

 

[Tufbusa]

It's great entertainment seeing you big HP fellas show up at a road race track and get spanked like a little school girl by a bone stock bike with nothing more in the saddle than an everyday street rider.

Big HP bragging rights is one thing, managing that HP around a corner is a whole different ball game. You may want to try shaving a lion's a$$ in a telephone booth before attempting a road course on big HP as they both have much in common!

 

[FloydV]

Interesting. Thanks guys.

 

[ATC'er]

One is what the manufacturers' advertise, the other is what you actually get when you're riding down the street.

 

[GNBRETT]

there isnt a hell of a lot of difference in crank and wheel HP on a bike going thru a manual tranny weighing 500 lbs or less. on a car with an auto u lose quite a bit but not on a bike and even more lost with a car with AWD. maybe 10-15 hp on a bike makn 200 hp vs. 75-100 with an auto car depending on hp.

but wat u make on the dyno wont be the same as wat u make on the street. seen many turbo cars dynoed in the safe or close to safe zone then go to the track and melt cause the load is different at the track. especially wen dealing with alky injection.

 

[mysticblu999]

It's great entertainment seeing you big HP fellas show up at a road race track and get spanked like a little school girl by a bone stock bike with nothing more in the saddle than an everyday street rider.

Big HP bragging rights is one thing, managing that HP around a corner is a whole different ball game. You may want to try shaving a lion's a$$ in a telephone booth before attempting a road course on big HP as they both have much in common!

Its also great entertainment to see you little HP fellers show up at a drag strip.

You can't compare the two. Apples and oranges, both taste good to me.