4th or 5th gear dyno runs

Usually done in 4th normally if it's a 5th it's noted on the chart. I wouldn't swear to the 10% though.

Why does it really matter waht gear its in? I know different gearing will give different results, but why 4th gear and not 3rd or 2nd etc... Thanks...

Red02FXST said:

How do you know if the chart is a 4th or 5th gear dyno run chart?
Most of them state they are 4th gear!! Isn't 4th gear standard?
I attached a dyno chart that doesn't say what gear.
What is the difference in real readings in HP and TQ?
Is it about 10%?

Click to expand...

The gear doesn't matter, except for recording top speed. That's not how the dyno works...

No matter what gear you are in, it takes a certain amount of energy over a certain amount of time to get that drum rolling. I ran mine a couple times trying both gears and the difference in torque and HP wasn't enough to indicate one method being better than the other. You can run it up in 1st gear if you want, and you'll still get HP and torque numbers that are very close to a 5th gear pull.... you'll just get there more quickly. Having a good rear tire makes more of a difference.

I've also heard people debate sitting on the bike, versus not sitting on it. Again, the difference is negligible. I didn't see a difference of more than 1-2%. The bike should be strapped down anyway, so whether or not you are sitting on it won't matter. That's my .02

Thanks for the info...

I guess that in 4th/5th gear it will take longer so the curve won't be as sharp/steep and you can see any irregularities at different rpm's alot easier.

IMHO, I'd sit on the bike. Its not about the best #'s on the dyno for me. Its about getting the best #'s for when I'm riding it, when it counts. Know what I mean... If sitting on the bike lowers the #'s, then so be it. Those are the numbers, more to the point the performance, I'd get if I was riding the bike. Thanks again.

I have made runs in both gears just becuase I have noticed people using the two here on the forum. For me 5th has always made a little more hp and tq
My dyno guy said that 4th is standard.
People also show corrected (sae) and uncorrected (actual) charts
Just to keep things confusing.

5th gear numbers seem to be higher than 4th. I ve heard 5% as the average difference. I wont offer a theory as to why this is, but I have read several posts explaining why 4th will be lower than 5th.

Hotshot;
okay, what is the difference between the sae and actuall?
Other than terminolly and 2 or 3 HP!!
SAE, I know means Society of Automotive Engineers.
Just numbers I guess.