MR or MRU road tractor

[Hook n ladder 1]

I'm looking down the road a year or two but thinking about making a over the road tractor on a tilt cab MR or MRU. The original idea is take this chassis and put a sleeper on it with some fabrication between the cab and sleeper. It would be a split tilt ( ths sleeper would not tilt) very similar to modern fire apparatus (Pierce Lance in specific). Used sleepers are a dime a dozen and could probably put any make sleeper on that chassis.

This idea is in it's infancy. I'm looking for problems or ideas. I understand the ride quality of a tilt cab. I drove an MR years ago for Waste management.

I'm probably looking for at least a 427hp with 13 speed. and air ride even maybe air ride on the front.

It's a crazy idea but could be a fun one.

Thanks for any help.

[RFCDrum]

There is a truck already like that from out west or Canada with a sleeper on it. I saw it on Hanks Truck pictures I think or Flickr. It was white. Drove a MR once as a chassis. Was delivering it from H And H Mack to Leach in Paramus NJ. Had 58 rears 300, Jake and a 6 speed just high low reverse. Was good vision I liked it except for the fact I banged my head on the ceiling a few times going down Rt 80. LOL

Rob

[bbigrig]

Have a good look at the Exhaust after treatment setup on the MRU's. The SCR system is huge and takes up about 3 feet of height as wide as the cab and almost 2 feet deep. I can imagine mounting that system or retro fitting a Pinnacle or Granite SCR set up frame mounted will be expensive. You may want to try to grab an early MRU (MP powered before SCR) that only has the a DPF exhaust filter.(those early ones had a lot of emission program problems I hear??) Would be a lot cheaper and easier to retrofit the DPF only ones. Don't mean to be a killjoy pointing out the after treatment B.S. Sounds like a neat project.

[j_martell]

I can't speak to the emission program problems, but a buddy of mine with an EPA 07 mp7 is on his 6th dpf now......

Sounds like a neat idea, I've always like the looks of cabover hiway tractors.....stupid emissions shit has to try and screw it all up.

[vision386]

Rob,is this the one you mentioned? I saw this up in Calgary a few years back,and never figured out whether that actually was a sleeper or not?.........................................Mark

[jaysm35a2]

I like the little USPS MR's

[RFCDrum]

Rob,is this the one you mentioned? I saw this up in Calgary a few years back,and never figured out whether that actually was a sleeper or not?.........................................Mark

That's it Mark thanks I knew I saw one somewhere.

[mowerman]

Rob,is this the one you mentioned? I saw this up in Calgary a few years back,and never figured out whether that actually was a sleeper or not?.........................................Mark

thats a cool rig,,,but i think its too small,for a bunk...bob

[Hook n ladder 1]

My idea includes a raised room sleeper. Not sure what size yet. I dont know if I need to stick with a Mack sleeper or if another make would work. Another issue is to try to hunt down an MR tractor ( id have to lenghthen the frame) or get a straight chassis maybe a garbage truck and convert it to a tractor.

The prob with that is Id have to replace the spring suspension with air ride. Anybody do this before and how bad did it cost???

The USPS trucks would be a good start but kinda short and have automatics which I wouldnt want. Since the MR is as aerodynamic as a brick the automatic would cut into my MPG.

That brings me to another question for you guys...I run a CH613 right now. its lines are sleeker and smoother than the MR. Does a conventional get that much better MPG than a tilt cab?

[GearheadGrrrl]

IIRC, the Mack engine MRs were limited to 400 hp, and the USPS ones were only 300 HP. The MRs aerdynamics aren't, it's pretty much a box and the long gap betwen cab and trailer on a tandem didn't help either. That said, I've always though an MR with a decent air deflector on the roof and a drom box would make sense in some operations, especially since the MH was long ago retired. As for finding an MR tractor already built, about your only choice is the USPS ones, as IIRC Mack doesn't list a tractor option currently and USPS was about the only outfit that bought MR tractors. Best of these would be the few ones USPS bought in 1998, they had the newer Allison automatic that gets better mileage. Power wise, I think an upgrade to 350 HP might be possible, but beyond that is iffy... There's folks here that know that stuff better than me. The USPS tandems were 135" wheelbase, and I think there's just enough space behind the cab for a small sleeper.

[kscarbel]

The USPS started out with MCs. When the MC was cancelled, Mack created a similar MR replacement.

The USPS's MC 6x4s (that I'm familiar with) had Reyco suspensions and Rockwell rears.

The export market MC sleeper cab is what you want.

..

[GearheadGrrrl]

I'm a retired USPS driver and spent a lot of hours in the MC and MR tractors. kscarbel is correct, the '84 MC tandems has Reyco spring ride on Rockwell rear axles with a 285 HP Maxidyne set down to 1900 RPM governed speed and a 5 speed Maxitorque. The next order in '91 was MRs with an E7-300 and 4 speed Allison on air, not sure if any tandems were included in that order. Next up in '96 were both singles and tandems with air ride on Eaton axles with electronic engine controls. For the '98 purchase USPS largely switched to CHs, but a few MRs were included in the order, with the electronic Allison 6 speed "World Transmisssion" replacing the older 4 speed. The last USPS purchase was in '06, and I believe it was all CX conventionals.

[Hook n ladder 1]

Thanks for the info. The foreign MC is funny lookin especially with the "R" model bumper.

[thomastractorsvc]

How do you plan on sealing the sleeper to the cab? That's what would be the PITA part as everything would be wet, cold or dusty

[57 bcr]

The guy with the Marmon motorhome (Ray Keens),has a boot between the cab and the camper unit.He has to be able to tilt the cab for service (of course). Someone on BMT must know him as he is usually at Macungie.He is a decent guy and could steer you in the right direction.

[kscarbel]

Thanks for the info. The foreign MC is funny lookin especially with the "R" model bumper.

All MCs, including the U.S. domestic market, came from the factory with what we at Mack call "corporate type" bumpers. Remember, the MC had a much lighter frame alike to the R-model (same 9 x 3.25 x .25" cross section), whereas the MR was altogether heavier like a DM.

[vision386]

Cabover with a conventional sleeper is nothing new,there were a ton of them back in the eighties,really popular with us bedbuggers (household movers) we had a guy leased on at Atlas when I was there with a KW very similar to the brown one pictured. Truck had a boot between cab and sleeper,and a snap-on cover for when the cab needed to be tilted. I imagine it would not be and easy project on an MR,way to much going on on the back of the cab!.......................Mark

[RFCDrum]

That's gotta be a small sleeper on the back of the white MR Mark. I like these 80's pics nostalgia.

Rob

[kscarbel2]

On 8/6/2013 at 10:30 AM, Hook n ladder 1 said:

Thanks for the info. The foreign MC is funny lookin especially with the "R" model bumper.

The Mack "corporate" (R-model) bumper was standard on the MC, both domestic and export, because unlike the larger MR, it was based on the R-model.

It was intended as a replacement for the MB 4x2 city tractors with customers like Overnite and APA, but then they began using the night time route tractors for daytime city delivery to reduce costs.

.