Whats your axle ratio

bluebird90

Senior Member
Joined
Mar 23, 2011
Posts
327
Location
Port angeles, Wa
Just wondering, With 11r/22.5 tires, what ratio is your rear end and how does it do at hiway speeds? I have 4.78 gears and are considering a change for better hiway speed. What do you have and what rpm are you at 60 mph?
 
My bus has a MD3060 transmission in it, 5th gear is overdriven at 0.75:1. My rear axle gear ratio is 5.38:1 I believe. I want to say at 60 mph my bus is running around 1800 rpms.
 
11r22.5 tires...4.78 rear gears...1:1 final drive on transmission...
60 mph is 2370 rpm

Would really like some 4.11 rear gears for 70 mph at the same rpm or 60 mph at 2025 rpm
 
I currently have 5.38 gears, 1:1 high gear transmission (it's a 5-speed manual), 10R22.5 tires, 55 MPH top speed at ~2500 RPM on a T444 engine.

A swap to 4:11 (or faster gears) is planned. The speed may be electronically limited in addition to the RPM governor. If so, it will be removed when the computer is reprogrammed for the new gears.
 
11r 22.5 tires. Allison at545 transmission. T444e. Rear end is 4.44 gears. Governor has been killed by Intl dealer. Will run down the highway at 70mph if I let it.

Sent from my SM-G955U using Tapatalk
 
My bus has a 1:1 final high gear (4th) in its AT545, 3.56:1 in the rear-end, and 19.5"-rim wheels (I hear they are 32" tall tires).

I can do 70-MPH @ about 2500-RMP on flat ground.
I can do over 70-MPH @ 2500-RMP downhill.

I cruise nicely with gentle fuel-petal at about 63-MPH @ about 2200-PRM on flat ground.

I don't remember for sure, but I think it's about 2000-RPM @ 60-MPH on flat ground.

Factor in a hill and all this changes.....

I know this motor has the torque to cruise between 1600-RMP & 1800-RPM.
Wish I had overdrive...
 
Last edited:
Started out with a 5.57 ratio. Was at 2500 rpm at around 65mph. Switched to a 4.67 ration and now at 65 I run around 2000 rpm. Glad I made the switch.
 
I have 6:83 gears with 10:00x20 tires turning my gas 427 at 3800 at 70 mph (48 inch tires), i would have thought you guys with an overdrive transmission would be able to run 70 mph. was looking into changing mine to a 3060 allison, have 640 now but it looks like that won't help much
 
2010 ford E350 super duty cutaway, 9 pass bus body with a wheelchair lift
5.4 L gas
5-speed auto ( ratios from 3.11 in first to .71 in od)
rearend 4.1
16" tires Lt 245/75/16
about 2100 rpm's at 70 mph
 
I just started looking at a 2003 Bluebird with 5.9l Cummins, an Allison 'PST2000' transmission according to the seller with 5.29 final gears.
I wasn't able to find out if it had an OD or what size the tires were.
But from reading, the 2000 tranny should have a lock up converter and may be able to have a 6th gear unlocked?
Any thoughts if this could get down the freeway at 60-65 under 2000 RPM? Or would I melt it down going over 55?
Thanks
 
rear end gears tires and transmission

3.73 rear end gears... direct drive in 5th gear and about .73 overdrive in 6th gear... manual transmission... 245 70 19.5 tires

1875 rpm at 65 mph in 6th gear - intended for flat land only

2525 rpm at 65 mph in 5th gear-- this is when I tow and the rpm start to slow down too much.

I can shift to 3rd at 65 mph but I will run very close to the governor and I risk going into defuel mode.

I have up to 3600 rpm available but that is only for emergencies. I really prefer to stay below 2800 rpm. I shift from 6th to 5th also when exhaust gas temperature goes to 1100 degrees.. The limit for exhaust gas temperature is 1275 degrees I prefer to stay a couple of hundred degrees below that if at all possible...

very much hot rodded cummins 5.9 12 valve estimated 400-425 hp and 700-800 ft lbs of torque

NV5600 6 speed transmission with dual disc clutch assembly

william
 
blackheart

your 2000 series allison should be direct in 4th and around .73 over drive in 5th. IF your transmission is capable then 6th should be around .61

you have not provided enough information to answer your question. Must have the rear gear ratio, and tire size. weight of the bus will also be a factor for any uphill performance estimates.

william --- HEY other people... chime in if I have the transmission information incorrect.
 

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