Gear Ratios
- Thread starter twodogsdaddy
- Start date
G
guest
Guest
>I think we'll do OK. As is, the eleven-man brain trust
>brings 232 years of combined industry experience to the
>project, with an average of 21.1 years each. But still, I'd
>have loved to have you on board. Truck driving experience is
>easy to find. Physics and engineering smarts seated behind
>the wheel is a rare commodity.
Ateam has had a change of heart with regards to experience being a good thing.
So lets not be negative about it... this is a positive event. Ateam is slowly learning. }>
>brings 232 years of combined industry experience to the
>project, with an average of 21.1 years each. But still, I'd
>have loved to have you on board. Truck driving experience is
>easy to find. Physics and engineering smarts seated behind
>the wheel is a rare commodity.
Ateam has had a change of heart with regards to experience being a good thing.
So lets not be negative about it... this is a positive event. Ateam is slowly learning. }>
What kind of help are you providing by telling others you are not going to discuss your truck build until it is on the road? What if there is another driver sinking that may be able to save a buck or two now, because of something you are doing or may have found out with your excellent research skills or the people involved? I know you have good help for many on this site, but it seems you are being selective in the help you provide? Where is the respect of a fellow driver? Why not help others when they ask for it and when it suits you?
I ask a question the other day where you replied with excellent info that may have cost me at least 2 or 3 hours if I would have researched myself. Because of the info you gave me I will save allot of money overall. Some may be spec’ing a truck and may need some help that you may have, or some ideas you and your team came up with, but you seem to be selective in the people you help (which is your right). Where is the RESPECT??? Why not help now? Why wait till the truck is built to offer any help?
I ask a question the other day where you replied with excellent info that may have cost me at least 2 or 3 hours if I would have researched myself. Because of the info you gave me I will save allot of money overall. Some may be spec’ing a truck and may need some help that you may have, or some ideas you and your team came up with, but you seem to be selective in the people you help (which is your right). Where is the RESPECT??? Why not help now? Why wait till the truck is built to offer any help?
vitaminchik
Seasoned Expediter
Hi everyone
Please help I am desperate need help with the ratio
the set up is 250 HP engine, allison 6 speed automatic double overdrive
rear gears 5.57 still crazy even though the transmission is with double overdrive
fuel economy don't want to mention it it's horrendous
powerband on the engine starts at 1500 rpm
I am deciding between 4.63 and 4.88 and am not sure what to go with
Allison scaan not much help their technician seems scared to recommend anything at all and repeats like mantra to stick around 5 with gears but I feel that its not the
ratio for expedite driving (linehaul call it)
Differential shop calculated that:
with ratio 4.63
at 1700RPM will be at 63 MPH
definitely I want to ride at least at 65MPH which will put me close to or at 1800RPM
seems I am at the power band and should be doing ok with the 4.63
still worried that it could take me forever to get to the cruise speed
and possibly have trouble doing hills if loaded over 10000lbs
Do I even have a hope to be practical to be able to shift into 6th speed and hold the cruise in there?
I know 4.88 will work for sure because this truck is being manufactored with either 4.88 and 5.77 gears same 250 hp and 6speed allison double OV/D
and again 4.63 is not too far from 4.88
I am torn, my truck is in the shop with the 4.63 ratio locked in the box waiting for install and I am scared as poop to proceed. Un till the ratio have not been installed I can swap it free for the 4.88 which is also available at the particular transmission and diff shop. Ohhh... what do I do any knowledgeable insight?
Please help I am going crazy over fears to screw up...
my fears came especially when i found this forum here is the link:
http://www.thedieselgarage.com/forums/showthread.php?t=22776
guys at this link say they used a tiny GMC topkick with allison 6 speed and even more powerful engine, a CAT with 300HP
and they claim to not even be able to cruise in the 6th gear.
the pull a camper as can be seen if you open the link there is the pic of their truck.
when I found this I stalled the work at shop and feel lost what to do? I felt pretty sure that 4.63 will work but now not really,
and i feel that still want the 4.63 somehow call it a stupid way hoping that it will work and I will be able to squeeze some fuel economy
1750 to 1800 at 65mph rpm seems to be the rpm that will work
as the power band on my engine starts at 1500 rpm well let it be starting at 1600 rpm, still seems to work...
Please help I am desperate need help with the ratio
the set up is 250 HP engine, allison 6 speed automatic double overdrive
rear gears 5.57 still crazy even though the transmission is with double overdrive
fuel economy don't want to mention it it's horrendous
powerband on the engine starts at 1500 rpm
I am deciding between 4.63 and 4.88 and am not sure what to go with
Allison scaan not much help their technician seems scared to recommend anything at all and repeats like mantra to stick around 5 with gears but I feel that its not the
ratio for expedite driving (linehaul call it)
Differential shop calculated that:
with ratio 4.63
at 1700RPM will be at 63 MPH
definitely I want to ride at least at 65MPH which will put me close to or at 1800RPM
seems I am at the power band and should be doing ok with the 4.63
still worried that it could take me forever to get to the cruise speed
and possibly have trouble doing hills if loaded over 10000lbs
Do I even have a hope to be practical to be able to shift into 6th speed and hold the cruise in there?
I know 4.88 will work for sure because this truck is being manufactored with either 4.88 and 5.77 gears same 250 hp and 6speed allison double OV/D
and again 4.63 is not too far from 4.88
I am torn, my truck is in the shop with the 4.63 ratio locked in the box waiting for install and I am scared as poop to proceed. Un till the ratio have not been installed I can swap it free for the 4.88 which is also available at the particular transmission and diff shop. Ohhh... what do I do any knowledgeable insight?
Please help I am going crazy over fears to screw up...
my fears came especially when i found this forum here is the link:
http://www.thedieselgarage.com/forums/showthread.php?t=22776
guys at this link say they used a tiny GMC topkick with allison 6 speed and even more powerful engine, a CAT with 300HP
and they claim to not even be able to cruise in the 6th gear.
the pull a camper as can be seen if you open the link there is the pic of their truck.
when I found this I stalled the work at shop and feel lost what to do? I felt pretty sure that 4.63 will work but now not really,
and i feel that still want the 4.63 somehow call it a stupid way hoping that it will work and I will be able to squeeze some fuel economy
1750 to 1800 at 65mph rpm seems to be the rpm that will work
as the power band on my engine starts at 1500 rpm well let it be starting at 1600 rpm, still seems to work...
Last edited:
purgoose10
Veteran Expediter
Cummins and the dealer is the only place to go. It depends on Tire size, what weight your pulling, transmission gearing and most of all what you want the truck to do. More to consider. The dealer will print you out what you want and you can decide.
Murraycroexp
Veteran Expediter
WAY too many factors to guess.
vitaminchik
Seasoned Expediter
vitaminchik
Seasoned Expediter
So i went with 4.88 rear end as my Allison rds 3000 has final ratio of .65
Also factory does not gear them lower than 4.88 in addition the info i got seems to point that it is barely holding the gear with 4.88 ratio and disastrous if go lower.
Will see might write back on what experience i get with this 4.88 one
set up 250 hp Isuzu engine
Allison rds 3000 six speed automatic double overdrive the fifth speed is overdrive .75 ratio
and sixth speed is overdrive .65 ratio
Rear end went from 5.57 to 4.88
Also factory does not gear them lower than 4.88 in addition the info i got seems to point that it is barely holding the gear with 4.88 ratio and disastrous if go lower.
Will see might write back on what experience i get with this 4.88 one
set up 250 hp Isuzu engine
Allison rds 3000 six speed automatic double overdrive the fifth speed is overdrive .75 ratio
and sixth speed is overdrive .65 ratio
Rear end went from 5.57 to 4.88
Murraycroexp
Veteran Expediter
LOL!! Wow!!! I got sucked right into that one!! I did go through the same issue with one of my trucks I bought from Freightliner Frank in Cincinnati. I ended up arranging a meeting between my driver and the Allison regional rep. He plugged up his laptop to it and "turned on" 6th gear. But I always regretted not researching the drivetrain more before buying that truck (used).
WanderngFool
Active Expediter
Are you saying you regret "unlocking" 6th gear?
I'm asking because recently I bought a mid 90s Freightliner straight truck with an Alison md3060 transmission. Most of the info I've been able to find on the tranny comes from R/V sites and it seems it's a 6 speed with an "eco mode". Mine is currently programmed to be a 5 speed and no eco mode.
I was quoted $150 by WW Williams in Toledo to have them check it out and if advisable do their laptop magic to it. Should I?
Last edited:
Murraycroexp
Veteran Expediter
No. Do it. Good move and the fuel savings will pay for the reprogram.
Murraycroexp
Veteran Expediter
Yes. Do it. I'm apparently speaking in riddles tonight. Too sleepy. Good night all.