Why do we not see the try to rear axle setups like British Columbia uses down here in the US? I like a lot of trucks that are up there as they would make excellent Mule Trains but I just don't see any of them being used down here. Why is that?
Are you talking tri-drives? You see them some but not a lot. I think the majority of the conditions down here don't necessitate the need. I had one in my fleet. I wasn't a fan. Crap turning radius and unless you geared stupid low the engineers derated the capacity based on slip torque. If I was running haul roads a lot and other marginal conditions I'd love to have a tri-drive with full lockers.
Yes, the tridrives. I had a guy tell me it was something to do with Bridge distance but I'm not sure if you knew what he was talking about.
My guess is that they can get the same weight on a regular tandem with a dead air lift axle and save tires on the back haul, and also less weight and expensive mechanical parts. If you get into trouble just lift the dead axle. Somebody correct me if I am wrong, everything is 5 axle in California.
Tri drives are about the only truck I have worked on for the last 15 years. Not my favorite. Tires GROAN! But there is a reason for it where I work. The big reason being that they work so well for what we are doing. We run tridem truck and tridem trailer, no wagons, no jeeps, no dogs. Straight tridems. All our trucks have locking diffs, they will go places. As far as a air tag axle, have never worked on one, not sure how well they would work on our horrible and steep roads.
I see them under some power line trucks. I've only ever driven one thing with tri drive, it was a Altec boom truck with a international tri drive carrier. It was a pain in the ***. If you were climbing any kind of a hill on gravel, it would instantly spin a tire. I was locking up diffs just to get out of our shop yard, which is uphill gravel to the road. Yes, my driveway is kind of steep, but I never lock anything with a tandem set up to walk out of there. If you had anything of a loose surface, it was always spinning a tire, which gets kind of hard on the rubber, the sharp rocks cut them all up. We see a lot of hard rock under surface, with some loose rock on top, and it just didn't work well in those conditions. I could see it being kind of nice if you were in soft conditions, and needed the axle load capacity, you would have all of them driving. That just tends to mean you get really really stuck, instead of a little stuck. But I'm usually on rock or pavement, and that one tri drive swore me off of them for good. If I really needed the load capacity, and got to choose, I'd rather have twin steer axles than tri drive, but I'm kind of used to the twin steer with the crane carriers. But that's a real expensive option if your buying trucks.
Why run a tridem when you have to get a permit to run over 80klbs on the highway? single-tandem-tandem axle does it day in and day out. Heavy haul is different. I have worked around the gas industry down here and I can't recall ever seeing a tri-drive but lots of heavy spec tractors with an air lift tag in front of the tandems.
I could see the tridem being nice for the B.C. area where you guys have a lot of moisture. Its rarely muddy here for long, and I think the dry loose conditions is a killer for the spinning a tire.
Crane Operator You hit that right on the head. As soon as the trucks come off the pavement, you throw the interaxle lock in or you will spin a tire. These things we have run the DD16 with the eaton MPX autoshift. In our yard if you mat the throttle with out the lock in you have a wheel spinning. Our trucks don't see much hiway haul, mostly off road. Yes muddy conditions most of the year. In the summer months when the roads dry up the tire count goes UP
Here in Washington we can go to 105,500# with 8 axles & no oversize load permit if under 8'6" wide.
Only Tri drive set up I ever worked on was a strict local less than 20 mile one way quarry hauler. Triple drive Mack DM660, 22 yard bed with added 26" steel sideboards, a tandem axle joe dog on a 6 bolt pintle dragging a 32' aluminum bed framed style dump trailer. Average weight with load of 1" clean rock or sand was 169,000 lbs. Truck made the trips two times per day to quarry and once per day sand plant alternating next day one quarry two sand plant. I Personally replaced two main drive shafts in that cripple as they tootsie rolled on a slight back road grade at a stop sign. Only took a slight back roll to get the two of them. Last one in was schedule 80 pipe not tube, took a full day to balance and two of us to hang it but was in the beast the day Glacial Ready Mix closed shop some twenty five years later, albeit with several ujoint failure replacements in between. Truck ran St. Louis Commercial zone, axle weight ONLY, no gross tare and NO interstate EVER.
In the states the only reason I'd go tri-drive is if I ran CA. Their law says common leveling on all three axles within 5% or something like that. If I'm gonna have a pusher or a tag axle it might as well drive. I've had two Cal legal 4 axles. One pusher and one tag. The one with the tag would get stuck on a speed bump.
See a lot more pusher lift axle sets nowadays in front of heavy tandems, still a dog to turn in tight quarters with the WB. Junkyard runs one.
If the job site is a little sketchy drop some single axil trucks in as they go better then a tandem or tri drive in adverse conditions . They pull through the mud & turn better then a multi axil rig every time .
I don't know what the law is but garbage trucks, concrete mixers, and super dumps here are running single wheel air lift axles sometimes, GVW 70,000. I have never seen one on a semi truck in this state.
It could be the desired gross weight or something. Having been through several CalTrans inspections if it isn't right you don't get the cute little drawing or any future permits for said configuration I always had better experiences with the northern CalTrans guys than the southern. I always planned ahead and had them meet me at Cozad in Stockton. Using their platform scale made life a lot easier! The main salesman is an misplaced Okie. Not sure if he's even there anymore. I think the last one I had done was 10 years ago.
Took me a bit, but here is our regulations. Page down until you get to the appendices, it shows the different logging combinations that we are allowed http://www.bclaws.ca/civix/document/id/loo89/loo89/30_78
As complicated as the US lot! And about as wordy as to legalese.
That made my head hurt!
i have only seen one tri drive truck in my life in this state it was a power line rig. without permit your only going to 80 so standard 5 axle is legal now as for dump trucks if you set up a super 18 with 3 pushers and a strong arm tag axle you can legally do 79000. most guys around here run simple 16 thats just 3 pusher axles you can so right around 70000 in them so they can haul right at 20 ton if the truck is built right. now heavy haul here is funny because AZ recognizes California set ups as well as other weird things. but most serious guys run murry or cozad trailers with a 16 tire group cause its good for 60000 and a 16 tire is 4 foot shorter than a tri axle you dont run tri axle to California because they have a king pin to tail length law at around 40 or 41 feet i believe thats what made 16 tire groups so popular
CalTrans likes the 16 tire trunion. Spread out 10 wide you get 60,000 on a purple permit. AZ and CA will give weight on a tri-axle group but it's only around 53,000. Yes CA has the kingpin law but once you're a permit load it doesn't matter anymore. They like short and wide for bridge loading and maneuvering around the mountain roads you can encounter in certain places. CA, AZ, NV, TX, NM like a 16 tire. A triple 16 with a heavy tandem truck will get you as much as a 13 axle and you're short enough you can run without a pilot car on a lot of routes. There is no "one size fits all" for heavy haul in the US.....
Yup Glad I am only a lowly mechanic and don't have to worry about this. Back in the late 90's when I was still in management and we were looking at going from fat trucks to Tri-drives I knew a bit more. But now I really don't care. Funny, retirement seems to be doing this to me, my give a **** is broken
So what I'm gathering from the guys I talk to you down here say the Canadian spread is a tire killer and a tri Drive makes it even worse. Although the positives are the Canadian spread does not sit down in the wash boards that the conventional trucks make climbing the hills so you have better traction.
I'm sure the scrub is terrible on them. The tri-drive I had was 60" spacings and I had to be careful what tires I ran or I'd mangle the shoulders in no time.
If I remember right In WA you can get a little more legal weight with a lift pusher single if the inner bridge is right (9'?). I think it's something like 43k for the tridem & 34 + 11 with 255's on the lift axle.
That sounds about like the federal bridge law weights and soacings as well. Helpful on ocassion in states that will give more than 80,000. In Oklahoma we can gross 90,000 off interstate if we can bridge it. Or you can do what I do and go where I want and not worry about it! Haha
WSDOT info. I still do not get it, must be the dummy in me.
Appears to be very similar if not identical to federal bridge law. Pick your number of axles, distance from first to last and see what you can gross.
That makes it way more simple. I was reading deep into one of their other PDF stalking about two sets of tandems and Bridge and this and that and the other, front-to-rear number of axles is much easier.
They like to make it hard to understand so they can issue more citations for mistakes in interpretation lol. It's all in the name of safety....they say. It's the almighty $ and nothing else.
Ah good old bridge formula, Damn I hated those scales too!!
Got to include the added axle numbers between!! or get ALL hosed up.
For WA go to https://secure3.wsdot.wa.gov/commercialvehicle/permits/public/AxleSpacingReport.aspx & plug in your numbers. If you click the "show detail" it will show the permitted & legal axle/group for the state. You can play around with #2 axle- 2 or 4 tires, drop, drop+steer. Just a bit of additional useless information for WA: a 4 tire non-steer drop does not count over 80k unless it's a permitted load . I know someone that found that out the hard way.