111hp/115ft lbs...should I be disappointed?
#61
01-26-2010, 11:05 PM
They dyno did change. What you measured was the true error in the dyno created by the dyno assuming what the rotational mass of the bike is. The power output of the bike didnt change at all.
Each bike isnt making what the dynojet says it is. The dynojet test is an approximation. it has numerous large errors.
If you wanna win a dyno shootout fit an ultra light weight 130 wide wheel, worn tire, a belt primary, take the IDS off, take your rear disk off and you will win.
But you will get your *** handed to you out on the road.
Each bike isnt making what the dynojet says it is. The dynojet test is an approximation. it has numerous large errors.
If you wanna win a dyno shootout fit an ultra light weight 130 wide wheel, worn tire, a belt primary, take the IDS off, take your rear disk off and you will win.
But you will get your *** handed to you out on the road.
The 800 pound drum didnt notice the few grams in rotational weight difference from a worn tire to a new one.
If you wanna win a dyno shootout fit an ultra light weight 130 wide wheel, worn tire, a belt primary, take the IDS off, take your rear disk off and you will win.
That will work great right up to the point the wheel starts hopping and spinning on the drum and makes you loose as fast as a top fuel car that spins!
#63
01-26-2010, 11:12 PM
Road Warrior
I didn say the bikes power changed, I said, "allowed the tire to slip more, making for a lower reading."
The 800 pound drum didnt notice the few grams in rotational weight difference from a worn tire to a new one.
If you wanna win a dyno shootout fit an ultra light weight 130 wide wheel, worn tire, a belt primary, take the IDS off, take your rear disk off and you will win.
That will work great right up to the point the wheel starts hopping and spinning on the drum and makes you loose as fast as a top fuel car that spins!
The 800 pound drum didnt notice the few grams in rotational weight difference from a worn tire to a new one.
If you wanna win a dyno shootout fit an ultra light weight 130 wide wheel, worn tire, a belt primary, take the IDS off, take your rear disk off and you will win.
That will work great right up to the point the wheel starts hopping and spinning on the drum and makes you loose as fast as a top fuel car that spins!
Putting on a light wheel and tyre cuts a few pounds off the static weight, but takes huge amounts off the rotational inertia.
It is well documented that new tires result in an apparent loss of hp on a dynojet dyno and it has nothing to do with slip.
#65
01-27-2010, 07:33 AM
Outstanding HDF Member
No, Dyno shootouts arent fair, they still have the same errors. You cant even compare 2 bikes on the same dyno on the same day unless they are completely mechanically identical, right down to tire type and amount of wear.
Any change in rotating mass will result in a different reading. Stuff like worn tires, wide tires, IDS, belt primary, chain secondary, laced / cast / forged wheels, all change the rotational inertia and therefore change the apparent power output during a sweep test. None of these things make a quantifiable difference out on the road.
The only test that is truly fair is the static test, ie where the dyno holds the motor at a constant speed and measures the net torque / hp made.
http://www.factorypro.com/magazine/m...ojet_dyno.html
Any change in rotating mass will result in a different reading. Stuff like worn tires, wide tires, IDS, belt primary, chain secondary, laced / cast / forged wheels, all change the rotational inertia and therefore change the apparent power output during a sweep test. None of these things make a quantifiable difference out on the road.
The only test that is truly fair is the static test, ie where the dyno holds the motor at a constant speed and measures the net torque / hp made.
http://www.factorypro.com/magazine/m...ojet_dyno.html
#67
03-24-2010, 03:14 PM
6th Gear
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#69
03-24-2010, 03:32 PM
Me saying the dyno is more accurate thanruning on the street was because it is taking the rider ability out of the equasion. That was a respounce of the post you made about the only true way to compare bikes is on the street. I said the dyno takes rider error ou of the equasion. If 2 identical bikes are racing on the street and 1 guy misses a gear, that doesn't mean that the bike lost, it means the rider lost. I am talking about comparing bikes, not riders.
