The Stovebolt Site Forums The Shop Area Driveline 3.55 truckers' gearset

I see motherTruckers has a 3.55 gearset avaialable for the 1/2ton, has anybody used these? What is your highway speed at 2600ish rpm?
Thanks oj

MTs sets are supposedly made by the same off-shore factory that makes the sets sold by other companies.

I have used two such sets.

Comparing highways speeds require knowing tire diameters and transmission top-gear ratio.

I run at around 68mph at around 2600 RPM.
I find it very nice (and more economical) to cruise at 60-65 MPH.

http://www.csgnetwork.com/multirpmcalc.html

Thanks Tim, 60mph sounds great to me. I see a gear change in the near future.

ojh,

You should also consider using the installation kits from Patrick's. It includes all the bearings/bushings/seals/gaskets that are needed.

tclederman, what transmission did you use with the 3.55 gears and what tire diameter to get you to the 68mph at 2600 rpm?

smoloney,

I have/will use all of these:
- original 1954 3-speed, 1:1 3rd gear
- SM420 4-speed, 1:1 fourth gear
- Hydra-Matic 4-speed, 1:1 fourth gear

Approximately 31"-31.5" loaded-diameter radial light-truck tires.

My speedometer is calibrated and has less than 1% error at 60mph.

2575 - 2616 RPM at 68 MPH, unless I am using that calculator incorrectly?

Why do you ask?

Im at a cross roads, a lot of work done basically mechanically (new 1954 235 engine), electric, cooling breaks and fuel is new. Last project was 4" drop axle and 3" blocks. I have been reading a lot about the 3.55 gear and how the tire diameter effects the rpm at 60mph. My next purchase was going to be wheels from wheel smith. The tires he is recommending do to the rim and back space needed put me at 29.1 tire diameter which is about an inch smaller than stock, the drop kit puts the tie rod end and shock mount in my section width of the tire so i cannot have any bulge as boththese are about 3/4 to 1" from tire. My concern is with the factory 3 speed switching to the 3.55 gears am i going to get the speed and keep my rpms down with that tire diameter. The last thing i want to do is spend $1200 on rims then also $1200 on gears and not get any results. If my best option is to upgrade to and open driveline which i dont really want to do as i really like three on the tree then i need to do it before ordering rims and tires. SO you can see why im concerned. ANY help would be appreciated, my plan has always been the 3.55 now im concerned.

Heres another contact that might help you. Tom's