Largest driven gear possible ????

Spudley

Spudley

Grippin' and Rippin'
Donating Member
Registered
Okay sportsfans....who out there has changed the front driven gear to a larger gear, and how large can I get away with ?. I'm not talking bottom end here, I'm talking top end. I was looking at this page running numbers : Gearing Commander: Motorcycle Gearing Ratio Sprocket RPM Speed Chain Calculator

We run a standard 17 to start. I'm wondering if I can get away with a 19....

Thanks for the read ! :super: Spud
 
I've seen big hp turbo busa's run a 20t front for LSR.

Also don't forget about the overdirve 5 and/or 6 trans gear.

Are you talking turbo or NA though?
 
Last edited:
What engine changes do you have...? You could run a 19 but no way is it going to pull 218ish-mph with stock power levels or even the basic bolt-ons...
 
I would love to hear the answer to this. My '08 redlines at 188mph with stock rear sprocket which leads me to believe the front may have been changed to a 16. Or do these bikes redline at that number?
 
Currently naturally aspirated. No plans for bigger and bolder. Just starting to wonder what the top-end characteristics are like with better torque in the range, and what ratios can be modified to offer the better mph. :super: 19t it is for starters !

Oh and Kaine, you're bumping the speed limiter, you're not topping out. Your speedometer, unless already corrected, is running optimistic also. :whistle:
 
nitrousjunkie said:
I ran a 19 for about 3 years,no problems.
Click to expand...

That's what I needed to know !! :super: I can only better understand the power / torque issues by understanding and practical application. You da' man !!!

I'll hold off on the 20t for now...... :oldcool:
 
Last edited:
technically it is the "drive" gear.. rear is driven :)

19 seems pretty tall for a street machine fwiw.. what are you trying to accomplish?
 
Last edited:
Drive not driven, thank you, sometimes I think too fast while I'm typing.

I'm trying to give the top-end range more "available" power. Not to mention, besides daily-driving, I like getting out in the sticks and running out the top end. I figure for daily-driving, the basic ratios are low enough to get me to and from work. Next step would be having the transmission gears replaced, and start building some "real" horsepower to get a much-better top end result. Inevitably, my goal is to head to Utah and run the stock class first, then go back with a modified. I've always been a mph kind-of-guy, not that I don't love the rush of 1/4 mile...:thumbsup: I'm not looking to be a name in the books, just one that went and "participated"...that'll be enough for me.... :oldcool:
 
Last edited:
Well FWIW... the gearing is only going to get you a very SMALL help.. MPH is almost a pure function of HP...

What I mean is when we are working on JUST top speed, gearing only helps if it was too short to start with.. (not enough gear) With the TRE installed, these bikes still have a tough time getting up against the rev limiter.. going up may in fact hurt your top end unless you have some kind of power added device.. (turbo, nitrous etc)..

Case in point is drag racing.. I can change gearing 2 to 5% and get NO increase in top speed but it will radically affect the first 1/8 mile.. (this is with nitro) car still runs 280 and change in the lights but the eight mile might vary 2 or 3 tenths and 20mph..

when it comes to ultimate top speed, aerodynamics make a big difference.. Do change 1 tooth on the front and try it out before getting too carried away.. (well unless you got a hair dryer hung on the side of that motor :) )
 
No hair dryer as of yet...that'll be the second trip North.... :super:

Thanks Randy, what I've noticed since 05' is that low to mid range we have hysterical ft/lbs, and yet it starts to fade up top due to wind resistance and the cam profile. I'm looking, with a little help from a Dyno to find a power / compromise. That's for the stock class efforts, ya' know, production. Then, I'll either go with more cc's and way more cam, or a much-less cam and a blow dryer.... :super: I'm no Dave O "Rest in Peace" (Nor do I have what he had for budget), but in the end I'm looking for huge mph and plenty of pony to hold it there.
 
Spudley said:
No hair dryer as of yet...that'll be the second trip North.... :super:

Thanks Randy, what I've noticed since 05' is that low to mid range we have hysterical ft/lbs, and yet it starts to fade up top due to wind resistance and the cam profile. I'm looking, with a little help from a Dyno to find a power / compromise. That's for the stock class efforts, ya' know, production. Then, I'll either go with more cc's and way more cam, or a much-less cam and a blow dryer.... :super: I'm no Dave O "Rest in Peace" (Nor do I have what he had for budget), but in the end I'm looking for huge mph and plenty of pony to hold it there.
Click to expand...
Yea that "hold it there" thing can be pretty tough.. our motors are grenades.. pull the pin and it has X seconds of WOT time (any real hotrod is like this) Is why you usually find the "really fast" guys are pretty much track rats.. to much $$$$ to be out dinking around street racing ect where traction sucks, safety is worse..
 
Mr Bogus said:
Yea that "hold it there" thing can be pretty tough.. our motors are grenades.. pull the pin and it has X seconds of WOT time (any real hotrod is like this) Is why you usually find the "really fast" guys are pretty much track rats.. to much $$$$ to be out dinking around street racing ect where traction sucks, safety is worse..
Click to expand...

True-dat. I'm an in-town straight guy, where outside of town anything goes. That doesn't mean I'm not wondering how my valve gaps, and spring tensions are doing while I'm pushing that needle. I just have a SH!D-load of enjoyment doing it. I'm the motorhead that thinks we should find a way to run the cams off of gear drive to eliminate that chain thingy.

I remember 1/4 mile days when every time you fired, you wondered if this was the last run.... :thumbsup: If I ever get my earnings straightened out and stabilized, I might just become one of those high-"fallootin", big pony types, with all the technology to make it run, and a ride just for it. In the meantime, I'm simply having fun with what I have to work with..... :super:

Thank God the Hayabusa comes with so much to start with !!!
 
Spudley said:
True-dat. I'm an in-town straight guy, where outside of town anything goes. That doesn't mean I'm not wondering how my valve gaps, and spring tensions are doing while I'm pushing that needle. I just have a SH!D-load of enjoyment doing it. I'm the motorhead that thinks we should find a way to run the cams off of gear drive to eliminate that chain thingy.

I remember 1/4 mile days when every time you fired, you wondered if this was the last run.... :thumbsup: If I ever get my earnings straightened out and stabilized, I might just become one of those high-"fallootin", big pony types, with all the technology to make it run, and a ride just for it. In the meantime, I'm simply having fun with what I have to work with..... :super:

Thank God the Hayabusa comes with so much to start with !!!
Click to expand...
think external belt drive on the cam setups... no reason on a gas motor you can not run them.. PLUS you get easy to adjust setups... I ran a Jessl belt drive on a 1500hp rat motor and never had any problems with it (gears suck to much power and weigh too much) and I could bump the cam timing up to 8 degrees either direction in about 3 minutes..
 
Belt drive........nice.... :oldcool: You are right on the gear / power issue. I've just never been a big fan of chain-drives in motors for anything......
 
You may as well buy a 18-tooth while you are at it. You aren't going to like the 19 when get out and run it maxed out. Unless you've got more mods than in your sig, it won't pull the gear with stock power levels or basic bolt-ons...
 
20/36 ????......Muah-ha-haaaa....:firedevil: Ummmm.....no. Not enough in her guys, as of yet. That would definitely be the "modified" re-visit in a couple years. Stock / production class first. 35 ????........ :super: Now the gearing study is getting interesting......
 
i'm running 18/40 (i think DR1300R is also) with full exhaust, PC, etc. that goes along with that...i love the set-up since i am not big into drag racing or popping wheelies but instead like to find some high speed sweepers out in the hills and have a little fun...there is plenty of power for taking off from a red light or cruising around town but the extra second of wind-up before having to shift on a long down-hill straight really makes a difference :whistle:
 
You must log in or register to reply here.

Similar threads

Shibumi
What effect does gearing have on dyno?
Replies
12
Views
1,004
Shibumi
Shibumi
G
Gearing Calculator/Shift Approximation sheet
Replies
11
Views
3,018
Amode
Amode
The Big Red One
Hey guys, have a question about redline and top speed limiters
Replies
5
Views
1,281
karnage
K
MX Tuner
Gearing question
Replies
2
Views
704
Professor
Professor
T
Going to the Dyno on Tuesday need advice
Replies
6
Views
685
shenoyp
S
Back
Top