RPMS at 70 MPH and 80 MPH stock gearing

[iride]

I a 45 rear sprocket two over stock and a stock front also a Speedo healer and I set it with a GPS unit So I am doing a true 70 mph at about 3800 RPM
at 80 mph i am doing about 4800 rpm
So I am guessing a stock bike should be running about 500 RPMs slower,,, 70 at 3300 and 80 at 4300
that sound about right to you guys????
Mike

 

[Rollin20z]

Wish I could help ya. Really don't go by what she reads, more of what she's saying. Did notice the other day when going thru some vids she get's the hiccups at 110 in 2nd which is 12k. And I'm running 45 rear stock front also.

I'm sure someone else will chime in with your answer here soon.

 

[sixpack577]

That's close.
I have a 18/46 and I remember it tachs over 600rpm more than it did with 18/43 at 65mph.
I can't remember the exact rpm then or now.

 

[mr8ball]

Mine is stock and today I looked as I was doing 70 and the RPM was 4K

 

[dadofthree]

gearingcommander.com will answer all your questions at 70 I'm running 4K on my stock gen II

 

[Trent]

on my 2011 with 600 miles today on highway 3800 RPMs @ 70, with a little headwind. I will check 80 tomorrow!

 

[squale147]

around 4k

 

[jphilipson]

And keep in mind that 80 on the speedo is like 74 - By 100 on the speedo you are off by 8 MPS, by 150 you are off by 12.

The GPS don't lie

 

[iride]

OK , Now I am confused, Because there is really no way to compare RPMs with out everyone being on the same page,,, The true MPH, We all know the speedo is off by about 8%
One of the 1st things I do to any bike is install a Speedo healer just because i can change my true MPH with my gearing changes, I also back up my changes with my GPS.....
Thanks for the replies
Mike

 

[Trent]

I got 4250 rpms for 80 mph today but I might have been on a hill. Flat areas are hard to find!!!!

 

[jphilipson]

I got 4250 rpms for 80 mph today but I might have been on a hill. Flat areas are hard to find!!!!

A hill would not affect gearing - and I get 4250 for 80 on the speedo and 74 on the GPS

 

[piratediverjefff]

4300-4400 @ 80 mph with 18/43

 

[powerjunkie]

Why would the rpms be different on a hill compared to a flat surface on a vehicle with a manual transmission? And head wind???? Anyone want to shed any light? Because on my vehicles with a manual trans the rpms are as constant as the speed no matter the grade or weather.