Non plunging 930 rear drive project.

[jersdunz]

I have an assembly mocked up of the cv drive with the new outer hubs.
Do any of you that have experience with the assembly of the Cv's see issue with this?
looking for feedback.. thanks




I have done some ratio calculations I am scratching my head a bit on my findings because it seems like a large ratio change.
Brian at DTS also has been sharing his experience with me as well.

Starting point with the 26" tires at 5.0:1
Tire change from 26 to 32 i came up with 23% increase in circumference.
5x1.231 = 6.155:1 then I was using Second and think i'll shoot for third gear the ratio difference of the two is 27%
6.155x1.27=7.817:1 seems Really deep.
That setup would be
Engine output 18, rpm input 26 = 1.444:1 * 5.4 @ rpm for a final drive of 7.8:1

Thoughts?

[Carlriddle]

So you are underdriving the 5.4 rpm box with the 26" to get the 5:1?
27% change seems a lot between 2nd & 3rd.  Whats the motor again?

I read where Dan (rpm) wasnt crazy about deep gear reducing into his boxes.

I'm running 5.38:1 with 31/32" tires. 1150lbs  Wish I woulda dropped a tooth for St A (had in tool box) so I'd say 5.5:1

[jersdunz]

2002 cbr1100xx the ratio information I retrieved from gear commander
when I installed the rpm I geared it up 1 tooth from 18 to 17 for 5.1:1 and it sucked.

I was stuck at the top of second and the bottom of third. slowed me down a lot.
here is the gear range of the bike as per gearing commander

[Carlriddle]

Mathematically your figures are correct.  But that's some awful deep gearing.  But you gotta be happy.

[jersdunz]

What really looks good to me is that 18% change from 3rd to 4th versus the 27% from second to third.. I very rarely use more than 2 gears.

at least in the past its been 2nd 80% of the time 3rd 10% and 1st 10% i've only seen 4th hand full of times in the huge bowls and that was rippin!!

[Carlriddle]

Start with the larger rear sprocket for the extra deep gearing.  Always drop the rear sprocket and shave the chain til ya happy camper. 

[jersdunz]

Start with the larger rear sprocket for the extra deep gearing.  Always drop the rear sprocket and shave the chain til ya happy camper. 

Shouldn't have to mess with the chain much I have lots of adjustment .. ( crosses fingers )

[dsrace]

ah just label it gearing trials and tribulation

here is a video of how it runs with the current gearing and blaster tires

[jersdunz]

Mathematically your figures are correct.  But that's some awful deep gearing.  But you gotta be happy.

I found another gear calculator...
I can see exactly that the speed i used to have in second i'll have in third my shift closes from 2200 rpm change to 1500 rpm change Very nicely done. Don't have a gear box just put a 1 in the rpm ratio slot.
Who ever made this did an awesome job

[Carlriddle]

I read somewhere on the internet (so it has to be true) to aim for 20:1 total gearing in 1st.  That was with a 31" tire.  That gear chart is slick!!  But that gearing you have puts you at 77mph, if you can pull max rpm in 6th gear.  Put your current setup in the chart(I'm sure you did) and see numbers.  BTW you will have to clearance the cv boot cups on the inboard cv's for the balls to slide thru.  The outter cv/stub, f150?  I'd get the hub bearing units from Ricks he's got the units made with the bolt pattern to run the easy-cheap chevy to wide 5 adapters.

Heres my gearing

[dsrace]

ok so this is in response to the pic above.

since there are no dimensions on the picture i have to ask...... are all the pivot points equal? as in does each point of pivot ( heim and cv) pivot on a equal plane to eliminate bind or telescoping? the easiest way to do this is to center the pivot point of the heims through the center of the pivot point of the cv but as i see in the picture they are not so if they do not pivot at the same time then the cv will have to plunge or atleast 1 cv on each side depending on how far off of center you are or you will get bind. always easiest and best to pivot through the centers 3d or up and down side to side  and in and out. but when space doesn't allow this i would think that if they were offset equally it still pivot right just add a load to the joints differently.

as to the gearing charts.....well that just hurts my head lol  they don't factor weight, drag or accel rate lol as in doubling the weight of the wheel and a 32" paddle with 1" tall paddles is more like 30" when calculating circumference for ground speed since the bald spot is actually floating imo that is.

[jersdunz]

ok so this is in response to the pic above.

since there are no dimensions on the picture i have to ask...... are all the pivot points equal? as in does each point of pivot ( heim and cv) pivot on a equal plane to eliminate bind or telescoping? the easiest way to do this is to center the pivot point of the heims through the center of the pivot point of the cv but as i see in the picture they are not so if they do not pivot at the same time then the cv will have to plunge or atleast 1 cv on each side depending on how far off of center you are or you will get bind. always easiest and best to pivot through the centers 3d or up and down side to side  and in and out. but when space doesn't allow this i would think that if they were offset equally it still pivot right just add a load to the joints differently.

The original setup was the way you describe it 3 pivots on the vertical plain....
the flanged u-joint yokes are thicker/taller than the cv's are, thus the inward offset 1.7ish so to deal with that I drew up new outers to match that offset. The only difference from inside to outside is the height of the pivot bolts I make the outer bolts 1/2" taller to help combat it folding in on it's self at droop.. it's either that or cut the whole back end out and start clean. ( which i'd like to do. BUT $$ )

if it installs, exactly like its drawn i'll have 0.055" of plunge. Of course that's like spotting a unicorn ... "Without some shrooms"

as to the gearing charts.....well that just hurts my head lol  they don't factor weight, drag or accel rate lol as in doubling the weight of the wheel and a 32" paddle with 1" tall paddles is more like 30" when calculating circumference for ground speed since the bald spot is actually floating imo that is.

I get what your saying its all just a guessing game right!!  .. it helps a lot on getting a close starting point though

[jersdunz]

I did forget to mention that .. The bitch about having the verticals pivots off plane like i'm doing is the axle as it rotates down. gets closer to the arm causing a big clearance issue on the cv cup at the bottom of the cycle.. it hits the arm.. i'll only get 36 maybe 38 out of it..

[dsrace]

since you have this modeled then rotate your inner a arm tab around the tube from 3 o clock to 7 or 7:30 positions and where does it line up in relation to the cv? at the wheel is easy to change

[dsrace]

what tooth count do you have on the counter shaft sprocket and input sprocket now? what is the gear reduction inside the rpm box?  i know you said on the phone you could run st a 90
% of the time in 2nd gear or more fo the time but what was the effective rpm range you stayed in to stay in 2nd gear? what is your motor rated at for max tq and hp and what rpms?