mumblymack76 Posted November 30, 2008 Share Posted November 30, 2008 I have always liked the off set Dm cabs and the U- cabs. From what I know the DM were for Dumper/mixer but I have seen literature with DM600 tractors but never one in real life, only the DM800 . I have also seen U600 tractors and was wondering what is the difference between the DM600 tractor and the U600 tractor? Is the DM heavier ? , because the few U600 I have seen seems to have smaller wheels compared to the DM. Quote Link to comment Share on other sites More sharing options...
HK Trucking Posted November 30, 2008 Share Posted November 30, 2008 A DM tractor would be the same heavy spec chassis used for a dump or mixer application, it's just that it has been set up with a 5th wheel and all the air and electric hookups to pull a semi trailer, instead of having a dump body or mixer mounted on it. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment Share on other sites More sharing options...
mumblymack76 Posted November 30, 2008 Author Share Posted November 30, 2008 A DM tractor would be the same heavy spec chassis used for a dump or mixer application, it's just that it has been set up with a 5th wheel and all the air and electric hookups to pull a semi trailer, instead of having a dump body or mixer mounted on it.Thanks, was the frame usually shorter if it is a tractor and were there any mechanical difference to a U- tractor? Quote Link to comment Share on other sites More sharing options...
HK Trucking Posted November 30, 2008 Share Posted November 30, 2008 Thanks, was the frame usually shorter if it is a tractor and were there any mechanical difference to a U- tractor?The frame can be whatever length was spec'd by the original purchaser, or it may have been shortened or lengthened afterwards to the length required.A U model tractor is a lighter duty tractor meant for general on highway type hauling, usually with a 12,000 lb. front axle and a 23,000 lb single axle or 34,000 lb. tandem drive axles, usually on 20 inch rubber. If I remember correctly the U models used a single 1/4 inch frame rail, whereas the DM in single frame configuration had a 3/8 frame rail, and the DM in double frame configuration had a 3/8 outer frame rail and a 1/4 inch inner rail. The DM frame is also a much higher section from top to bottom and tapers between the cab and drive axle(s).Most DM's had an 18,000 lb. or 20,000 lb. front axle and 38,000, 44,000, 55,000 or 65,000 lb. tandems or the 38,000 lb single drive axle, usually on 22 inch or 24 inch rubber.I'm generalizing here based on what I've observed over the years, I'm sure there are exceptions on trucks that were custom spec'ed for special applications. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment Share on other sites More sharing options...
mumblymack76 Posted December 5, 2008 Author Share Posted December 5, 2008 The frame can be whatever length was spec'd by the original purchaser, or it may have been shortened or lengthened afterwards to the length required.A U model tractor is a lighter duty tractor meant for general on highway type hauling, usually with a 12,000 lb. front axle and a 23,000 lb single axle or 34,000 lb. tandem drive axles, usually on 20 inch rubber. If I remember correctly the U models used a single 1/4 inch frame rail, whereas the DM in single frame configuration had a 3/8 frame rail, and the DM in double frame configuration had a 3/8 outer frame rail and a 1/4 inch inner rail. The DM frame is also a much higher section from top to bottom and tapers between the cab and drive axle(s).Most DM's had an 18,000 lb. or 20,000 lb. front axle and 38,000, 44,000, 55,000 or 65,000 lb. tandems or the 38,000 lb single drive axle, usually on 22 inch or 24 inch rubber.I'm generalizing here based on what I've observed over the years, I'm sure there are exceptions on trucks that were custom spec'ed for special applications.I also notice that on the U-model the hood is extended longer downwards between the lights and the bumper compared to the DM or the R. I just noticed it today after going through the many wonderfull pictures on this site. I always knew there was something different in the looks on the hood between the DM and the U but could never quite figure out what it was. Quote Link to comment Share on other sites More sharing options...
HK Trucking Posted December 5, 2008 Share Posted December 5, 2008 I also notice that on the U-model the hood is extended longer downwards between the lights and the bumper compared to the DM or the R. I just noticed it today after going through the many wonderfull pictures on this site. I always knew there was something different in the looks on the hood between the DM and the U but could never quite figure out what it was.Not necessarily.Most U models shared the same hood as the DM, but I've seen those "Roadway" U models with that higher hood that you speak of. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment Share on other sites More sharing options...
David Posted December 6, 2008 Share Posted December 6, 2008 The high hoods might be a U700. There was some discussion a while back on another thread about these. Quote Link to comment Share on other sites More sharing options...
David Posted December 6, 2008 Share Posted December 6, 2008 http://s8.photobucket.com/albums/a12/bigma...nt=100_3129.jpgThis is Roger Gerhart's U700. Quote Link to comment Share on other sites More sharing options...
mumblymack76 Posted December 6, 2008 Author Share Posted December 6, 2008 http://s8.photobucket.com/albums/a12/bigma...nt=100_3129.jpgThis is Roger Gerhart's U700.Thanks, do you know why the U700 had a taller hood? Could be engines, different frame etc? Quote Link to comment Share on other sites More sharing options...
mackcl96 Posted December 6, 2008 Share Posted December 6, 2008 Thanks, do you know why the U700 had a taller hood? Could be engines, different frame etc?Vendor engine's Quote Thanks for hearing me out.You can have the soap box now---------JIM Link to comment Share on other sites More sharing options...
mackcl96 Posted December 6, 2008 Share Posted December 6, 2008 Not necessarily.Most U models shared the same hood as the DM, but I've seen those "Roadway" U models with that higher hood that you speak of.Roadway used Detroit Quote Thanks for hearing me out.You can have the soap box now---------JIM Link to comment Share on other sites More sharing options...
jeffbyrne Posted December 7, 2008 Share Posted December 7, 2008 I have always liked the off set Dm cabs and the U- cabs. From what I know the DM were for Dumper/mixer but I have seen literature with DM600 tractors but never one in real life, only the DM800 . I have also seen U600 tractors and was wondering what is the difference between the DM600 tractor and the U600 tractor? Is the DM heavier ? , because the few U600 I have seen seems to have smaller wheels compared to the DM.the frame of a U is completely different to a DM 600, U uses the same frame as an R600, the DM 800 & R800 use their own frame with a straight thru profile, the DM 600 has its own frame similar to a B model, but with a deeper section from front to behind the cab. Hope this might be of interest to you, regards jeffro Quote Link to comment Share on other sites More sharing options...
mumblymack76 Posted December 14, 2008 Author Share Posted December 14, 2008 (edited) Did all the U- models keep the flat back cab after the DM/R models went to the curved back in 74? I notice some U-models of 80s build with the flat back. Edited December 14, 2008 by dmmack76 Quote Link to comment Share on other sites More sharing options...
jeffbyrne Posted August 31, 2012 Share Posted August 31, 2012 A similar question was asked recently. Quote Link to comment Share on other sites More sharing options...
umodelnut Posted August 31, 2012 Share Posted August 31, 2012 Did all the U- models keep the flat back cab after the DM/R models went to the curved back in 74? I notice some U-models of 80s build with the flat back.All the U models had the flat back cab. Only the DM's got the change of the Plus 3 Cab. Quote Link to comment Share on other sites More sharing options...
ap40rocktruck Posted August 31, 2012 Share Posted August 31, 2012 The U-700 had the taller hood to accommodate a bigger rad to cool the V-8 Mack engine. New Penn had quite a few of these, real bugger to work on....Ap40 Quote Richard MarkOwner / Master Model Maker Industrial Model DesignAp40rocktruck Link to comment Share on other sites More sharing options...
umodelnut Posted September 1, 2012 Share Posted September 1, 2012 The U-700 had the taller hood to accommodate a bigger rad to cool the V-8 Mack engine. New Penn had quite a few of these, real bugger to work on....Ap40U700's were made to acommadate bigger Mack V8's. I know they also had an option for Detroits. 6V71's, and 8V71's I think. Think they coulda had Cummins too. Quote Link to comment Share on other sites More sharing options...
JumperAndSon Posted September 1, 2012 Share Posted September 1, 2012 Vin, a U700 with an 8V71? That would be awesome! I'd strait pimp that, errr......strait pipe that! Quote Link to comment Share on other sites More sharing options...
JumperAndSon Posted September 1, 2012 Share Posted September 1, 2012 Vin, a U700 with an 8V71? That would be awesome! I'd strait pimp that, errr......strait pipe that!Remember, if we' strait' pimpin' it, we gotta get da twonnyfoe(.5)'s up on 'at piece.Ben Quote Link to comment Share on other sites More sharing options...
umodelnut Posted September 1, 2012 Share Posted September 1, 2012 Yea Cousin. Im pretty sure there was 8V71's. I'll have to look at the build sheet again. Quote Link to comment Share on other sites More sharing options...
JumperAndSon Posted September 2, 2012 Share Posted September 2, 2012 Yea Cousin. Im pretty sure there was 8V71's. I'll have to look at the build sheet again.Yea, there was, I've seen them. Yellow and Roadway used them, I think.Ben Quote Link to comment Share on other sites More sharing options...
Offset-U-bet! Posted September 2, 2012 Share Posted September 2, 2012 I'm sorry but a Puppy with a externally well lubricated Detroit (or any other motor) in it? To me thats always been sacrilege! Pure pedigree or nothing! Just my input! Quote Link to comment Share on other sites More sharing options...
umodelnut Posted September 2, 2012 Share Posted September 2, 2012 Offset-U-bet!!! Thats a great name!!! Do you have any U models, pictures etc?! Quote Link to comment Share on other sites More sharing options...
Offset-U-bet! Posted September 2, 2012 Share Posted September 2, 2012 Don't have one as of yet! I grew up around them My father drove them on the east coast for 20 years. As a child a remember going with him and I would love to restore one in his memory someday!Offset-U-bet!!! Thats a great name!!! Do you have any U models, pictures etc?! Quote Link to comment Share on other sites More sharing options...
umodelnut Posted September 2, 2012 Share Posted September 2, 2012 Don't have one as of yet! I grew up around them My father drove them on the east coast for 20 years. As a child a remember going with him and I would love to restore one in his memory someday!Well Im 12 years old, and just loved Macks all my life especially U models. I got my grandfather into Macks, haha, and now my Papa (grandfather) are restoring a U model. Do you have any pictures of them U models your father drove? Whod he drive for? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.