Vladislav Posted February 15, 2013 Share Posted February 15, 2013 It's really not easy to make a math with inches you guys used to.Metric count goes more just.But...My telephone said me 138.16 inches means 0.00218 mile (hope not a sea mile).2100x60/8.24/0.69=22161.25 rear wheel revs per hour.22161.25x0.00218= 48.3 miles per hourI mistaken about multiply by ratio. Divide by ratio because tranny makes revs slower.About 00 - my TRD-37 is single overdrive. Quote Никогда не бывает слишком много грузовиков! leversole 11.2012 Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164632 Share on other sites More sharing options...
Bigdogtrucker Posted February 15, 2013 Author Share Posted February 15, 2013 One thing that always is different when I mess with the formula is "actual" tire size.The same size tire but different brands are different actual sizes.Even when I have measured the tires myself there are variables.The main deal here is that it is a B81 dump truck and dump trucks of that time period were about a 50 mph truck.I recall that true 24" rubber on trucks so equipped were branded "not to exceed 55 mph".JimTrue for sure.Is 2100 the max RPM is should spin this engine or would a tad more be OK? Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164634 Share on other sites More sharing options...
j hancock Posted February 15, 2013 Share Posted February 15, 2013 Maybe a little more but it won't gain you much more mph Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164635 Share on other sites More sharing options...
HK Trucking Posted February 15, 2013 Share Posted February 15, 2013 One thing that always is different when I mess with the formula is "actual" tire size. The same size tire but different brands are different actual sizes. Even when I have measured the tires myself there are variables. The main deal here is that it is a B81 dump truck and dump trucks of that time period were about a 50 mph truck. I recall that true 24" rubber on trucks so equipped were branded "not to exceed 55 mph". JimAnd those engines were designed to run between 1500 to 2100 RPM. If you wanted to run on the highway, there was no choice but to hold it to the floor & let it run against the governor. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164636 Share on other sites More sharing options...
HK Trucking Posted February 15, 2013 Share Posted February 15, 2013 I've "jacked up" ENDT 673 & ENDT675 &676 motors to 2400 with no apparent ill effects. I wouldn't go any higher than that though. Quote "If You Can't Shift It Smoothly, You Shouldn't Be Driving It" Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164637 Share on other sites More sharing options...
j hancock Posted February 15, 2013 Share Posted February 15, 2013 And those engines were designed to run between 1500 to 2100 RPM. If you wanted to run on the highway, there was no choice but to hold it to the floor & let it run against the governor.Funny how years ago their were lots of tire problems on a hot Friday afternoon while everyone was hightailing it back to the garage as fast as they could go. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164638 Share on other sites More sharing options...
Lmackattack Posted February 15, 2013 Share Posted February 15, 2013 True for sure.Is 2100 the max RPM is should spin this engine or woulIf I recall 2100 was max under load and the dash said to never exceed 2300. Even with the maxidynes we ran them flat foot on the hi-ways 61.5 MPH all day,every day Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164644 Share on other sites More sharing options...
Superdog Posted February 15, 2013 Share Posted February 15, 2013 One thing to remember, a single "0" on the end is single overdrive(ie: 7220). A "00" on the end means double overdrive.You are thinking of a Fuller,Larry,RTO and RTOO. Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164647 Share on other sites More sharing options...
Bigdogtrucker Posted February 15, 2013 Author Share Posted February 15, 2013 I guess if she'll crank down the road near 50 that's not so bad.Just not a highway truck! Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164648 Share on other sites More sharing options...
Freightrain Posted February 15, 2013 Share Posted February 15, 2013 You are thinking of a Fuller,Larry,RTO and RTOO.Oh crap..........it is Friday and I just don't wanna think hard enough LMAO!!!! Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164650 Share on other sites More sharing options...
other dog Posted February 15, 2013 Share Posted February 15, 2013 I guess if she'll crank down the road near 50 that's not so bad.Just not a highway truck!yeah, that's about all I can do. I remember the first time I drove the mixer home, going down rt. 24 in Appomattox. The speedometer doesn't work, and my wife was following me in the car. It was loud, springs so stiff you could feel a bump if you ran over a dime in the road, and I was just flying. Thought I was doing 100+ anyway.When I got home I said "how fast was I going?"She said "about 50, except when you went down Rocky Run hill- then you got up to almost 55". 1 Quote Producer of poorly photo-chopped pictures since 1999. Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164655 Share on other sites More sharing options...
Bigdogtrucker Posted February 15, 2013 Author Share Posted February 15, 2013 Thought I was doing 100+ anyway.LOL that's classic,as long as you "feel" your going at a good clip it's not so bad!At least my B75 has some longer legs! Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164657 Share on other sites More sharing options...
Mike Posted February 15, 2013 Share Posted February 15, 2013 LOL, I drove mine up I-65 North from Nashville, several years ago, to keep from going back roads( shifting and air brake issues was the reason ) and it was so loud, I thought I was going 70 mph, but only wondered why everone else was going 100 mph. Finally got home some 27 miles traveled and asked the g/f how fast was I going. She LHAO at me and said 47 mph. I was shocked to say the least.Remember Loud Pipes Save LivesAt least that is what the Harley riders say.mike 1 Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164661 Share on other sites More sharing options...
jackb61sx Posted February 16, 2013 Share Posted February 16, 2013 Our B-61sx with the quad and 11,00x24 Bias ply will only do tops 52 mph and its powered by a 673c. Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164767 Share on other sites More sharing options...
Bigdogtrucker Posted February 16, 2013 Author Share Posted February 16, 2013 Would higher ratio center sections be hard to find these days? Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164770 Share on other sites More sharing options...
jeffbyrne Posted February 16, 2013 Share Posted February 16, 2013 How about, all Quads are overdrive, but a '0' on the end means double overdrive Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-164780 Share on other sites More sharing options...
Maddog13407 Posted February 17, 2013 Share Posted February 17, 2013 always thought the 0 meant overdrive and 20 meant double over. never really understood the TRQ7210 and TRQ7220 differences. guess they were both double over just different ratios? or the 7210 was an 18 speed and 7220 was a 20? they they made a regular 20 and have seen both 20 and 18 speed tags that said dont use 5th in low and low split. Quote Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-165120 Share on other sites More sharing options...
other dog Posted February 17, 2013 Share Posted February 17, 2013 Herb is right, 4th. is direct drive in the main transmission, 5th. is overdrive. Direct is direct drive in the compound, hi split is overdrive. So if the main's in 5th. gear and the compound's in hi split that gives you double over. 4th. in the main and hi split in the compound is almost the same gear ratio as 5th. in the main and direct in the compound- that's why 4th. hi split to 5th. hi split is the last shift and you have 18 speeds instead of 20. Quote Producer of poorly photo-chopped pictures since 1999. Link to comment https://www.bigmacktrucks.com/topic/29960-top-speed/page/2/#findComment-165132 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.