tire size = mph?

[tiny110]

new info needed.... anyone driven there m35a2 over 65mph? if so what kind of set up do you have?

i have been looking all over and i cant seem to find the info i need anywhere. i will be getting my first MV (a deuce and a half) by the end of Aug. What im needding to know is about tire size and how many MPH a given tire will get me. And how hard is it on the truck starting and stopping with something like 46", 49" or 53" tires. im going to keep it a 6x6 and spread the axels if needed.

 

[Bob H]

This all has been covered in this forum,
search & read
Basically the taller the tire, the higher the top speed, the harder to stop & slower acceleration.

 

[m-35tom]

it will kill the performance. for the same or even less money you can add .69 overdrive.
certainly less work than spreading rear axles.

mph = ( rpm * radius) / ( 168 * ratio)

tom

 

[camoyj7]

I run 395's (46") on mine and 55mph is around 2100rpm.

 

[tiny110]

Yea Tom I was looking at your website yesterday. The fastest I want to go in it is 65 but I would like to be able to cruise at 65. Not having to spread the axels would be great! Everything for 200mi around me is flat so climbing a hill is not going to be a prob for me. I want to run singles on it for sure... do you thank I could run 395s with your overdrive or would that be to much? Thanx for the help...

 

[patracy]

It will be too much, plus the tires are only rated to 56mph. I've got 395's on one of my trucks.

I'd go with either the OD gears or 395's. You'll gain some "looks" with the tires. But loose some performance. The gears will allow you to cruise a little faster. But remember, the multifuel engine doesn't like to be above 2600rpm.

IMHO, get the gears or the tires and be happy to cruise at 55mph without running against the governor.

 

[clinto]

Tom's OD kit also fixes the infamous 2nd gear issues these transmissions have.

 

[m-35tom]

2100 rpm with 395s and .69 od is 62 mph. it would be nice but the multifuel will never do this. otherwise the .69 offers just a very little bit more mph at any given rpm over 395s, this with 14.5r20

tom

 

[73m819]

TRY THIS
Calulators from www.4Lo.com

 

[Ridgerunner]

In a stock five speed Deuce tranny, what is the over-drive ratio?

 

[ApopkaFL]

interesting to see with the 14.5 i am changing to 1600 R20 at 50 mph ill be running 60mph. I wonder with they cat 3116 with Allison automatic , I wonder how may RPM I will turning at WOT

 

[patracy]

interesting to see with the 14.5 i am changing to 1600 R20 at 50 mph ill be running 60mph. I wonder with they cat 3116 with Allison automatic , I wonder how may RPM I will turning at WOT

Allison 1545 = 1:1 in top gear. So... about 61mph would equal close to 2700rpm with a 53" tall tire. (Adjusted to also account for non-lockup)

 

[ApopkaFL]

Well I hope to drop the RPM so it is not running that much RPM at WOT

 

[tiny110]

In a stock five speed Deuce tranny, what is the over-drive ratio?

5th gear is .79

 

[tiny110]

So I have done so number crunching... If i put in the .69 overdrive and have 46" tires i would be doing 65mph at 2200rpm. Sound right? It would be the same gearing as a truck thats running 53" tires... Is there any one out there running 53" tires that has had there truck up to 65mph??? If a truck on 53" tires can do it then it sounds like the way im thinking of doing it would be better. Less tire to get going and better gearing 1st-4th. Better braking. And EZer for the truck getting up to speed. So anyone out there doing 65mph+ on 53" tires???

 

[doghead]

Don't forget to factor in aerodynamics, mass(14000lbs) and the fact that you have less than 100hp at the wheels. You're gonna run out of power.

 

[73m819]

So I have done so number crunching... If i put in the .69 overdrive and have 46" tires i would be doing 65mph at 2200rpm. Sound right? It would be the same gearing as a truck thats running 53" tires... Is there any one out there running 53" tires that has had there truck up to 65mph??? If a truck on 53" tires can do it then it sounds like the way im thinking of doing it would be better. Less tire to get going and better gearing 1st-4th. Better braking. And EZer for the truck getting up to speed. So anyone out there doing 65mph+ on 53" tires???

ARE you going to do anything about the BRAKES on a old 50 mph designed truck, or not worry about it. if you are looking fo 65 down the freeway go buy a civi truck

 

[ApopkaFL]

Its M35A3 Deuce. I do not see a problem with the brakes. It may be 50 year old design but the system is not that old.

 

[73m819]

Its M35A3 Deuce. I do not see a problem with the brakes. It may be 50 year old design but the system is not that old.

He is talking about a a2 because he is talking about changing the OD in the trans, the a3 has a AUTO

 

[tiny110]

ARE you going to do anything about the BRAKES on a old 50 mph designed truck, or not worry about it. if you are looking fo 65 down the freeway go buy a civi truck

well mister negative... im not a idiot!
im a former over the road truck driver. so i know how to drive a big truck. the brakes cant be that bad! im not wanting to load it up with 22000lb and go down the hwy at 65mph. i do all my work on all my vehicles and they are in the best running condition any time thay are out on the road. my deuse will be completely gone throught befor it will ever go out on the road. And if the brakes are that bad there are things that i can do about that. IT WILL be done right!