Dyno and Wheel size

[aldean]

Can anybody tell me does wheel size change the dyno runs? Stock tire is 16" and I will be going to an 18". Will it make a difference on the outcome?

Thanks

[Totenkopf]

Originally Posted by aldean

Can anybody tell me does wheel size change the dyno runs? Stock tire is 16" and I will be going to an 18". Will it make a difference on the outcome?

Thanks

If you change from 16" to 18" wheel but select a low profile radial tire, it is possible to maintain the same overall diameter and that would be same net effect.

If you change the diameter either higher or lower significantly, it will affect the overall gearing and you would look to see that your wheel speed is not getting silly during the pull.

[claydbal]

Originally Posted by Totenkopf

If you change from 16" to 18" wheel but select a low profile radial tire, it is possible to maintain the same overall diameter and that would be same net effect.

If you change the diameter either higher or lower significantly, it will affect the overall gearing and you would look to see that your wheel speed is not getting silly during the pull.

ad look at the wheel itself. example, an 18 that is laced and thin aluminum VS. a cast aluminum. the cast will be heavier, thus requiring more power to spin it up. so a 16 cast will give you a gearing advantage, but an 18 lightweight will give you weight advantage. i will take the weight advantage!!!!!!!

[Colonel Sanders]

The weight of the wheel can make a sizable difference. In inch taller or shorter is going to matter too. Taller = a numerically lower overall gear ratio and will rob less power fighting inertia....same effect as changing the front pulley to a higher tooth count thereby bringing cruising RPMs down.

If you're asking yourself what did I mean by "rob less power fighting inertia" just understand that when you're accelerating all of those parts that make up your engine and drivetrain, there is a certain amount of power that is robbed in doing so. The slower you accelerate the parts, the less power is robbed. That's a large part of the reason that you will always get a higher dyno reading in 5th gear than in 4th.

[Totenkopf]

Originally Posted by claydbal

ad look at the wheel itself. example, an 18 that is laced and thin aluminum VS. a cast aluminum. the cast will be heavier, thus requiring more power to spin it up. so a 16 cast will give you a gearing advantage, but an 18 lightweight will give you weight advantage. i will take the weight advantage!!!!!!!

you are right on Dennis! in drag racing the bikes, we go to a lot of expense to reduce weight. Last year I bought a new dual spider lightweight PM racing rear wheel (it replaced a much heavier billet wheel) and when matched to a new lighter weight 10.5" slick for the Pro Gas bike, that when combined, reduced our rear wheel assembly weight by 8-9 lbs, iirc. roughly a 20% weight savings of the rotating mass which will translate to improved acceleration due to less loss.

By the way, interesting side comment, I bought that wheel from Schumacher Racing in Brownsburg, IN, it came off of Angele's US Army Pro Stock Motorcycle Suzuki. It happened to be a perfect fit for the Pro Gas bike. Plus also got the complete set of 10 matching Kosman rear sprockets to go with the wheel. Quite the find!

[claydbal]

Originally Posted by Totenkopf

you are right on Dennis! in drag racing the bikes, we go to a lot of expense to reduce weight. Last year I bought a new dual spider lightweight PM racing rear wheel (it replaced a much heavier billet wheel) and when matched to a new lighter weight 10.5" slick for the Pro Gas bike, that when combined, reduced our rear wheel assembly weight by 8-9 lbs, iirc. roughly a 20% weight savings of the rotating mass which will translate to improved acceleration due to less loss.

By the way, interesting side comment, I bought that wheel from Schumacher Racing in Brownsburg, IN, it came off of Angele's US Army Pro Stock Motorcycle Suzuki. It happened to be a perfect fit for the Pro Gas bike. Plus also got the complete set of 10 matching Kosman rear sprockets to go with the wheel. Quite the find!

didnt she go back to the 2 georges? on a buell?

[Totenkopf]

Originally Posted by claydbal

didnt she go back to the 2 georges? on a buell?

yep! I got this wheel and sprockets last year when she was still running the Suzi.

[claydbal]

one thing fore sure tote, that chic has a reaction time from hell. every time!!!!!!

[Totenkopf]

Originally Posted by claydbal

one thing fore sure tote, that chic has a reaction time from hell. every time!!!!!!

not to take anything away from her, but a good part of that is the crew chief dialing in the bike's reaction time to her response to the pro tree, as long as she is consistent. we do the same thing with the clutch on the pro mod and pro gas, you can adjust it to leave a little sooner or later depending on how the pilot is seeing the lights that day. interesting stuff for sure!

[claydbal]

Originally Posted by Totenkopf

not to take anything away from her, but a good part of that is the crew chief dialing in the bike's reaction time to her response to the pro tree, as long as she is consistent. we do the same thing with the clutch on the pro mod and pro gas, you can adjust it to leave a little sooner or later depending on how the pilot is seeing the lights that day. interesting stuff for sure!

yep, i understand the pros actually have eye surgery to better see the light. no pro here, i leave crazy on a protree, all effort goes to watching the light and none to clutch work. LOLOL. a .5 light is much easier for me because im old and slow!!!!!!!!!