Steer axle weight

[neetchracer]

New to posting but have read a lot of stuff here for a long time. Short story. I'm a drag racer and recently sold my diesel pusher in favor of a truck conversion for hauling my race car. The pusher and tag trailer was a bit of a handful in the wind and my wife was stressed about some of our trips....lol. I decided a gooseneck style toter/trailer would provide the best possible towing. I found a sweet deal on a 2004 Columbia 15' box with a gooseneck hitch. I then picked up an old 40' gn trailer that I will be raising the roof and converting to a double stacker, two car trailer. We found towing with this beast is awesome.....even in the wind. 500 hp is just a bonus.

Now to my problem. Before starting work on the trailer I wanted a base weight to reference during the build. I took the complete rig to a local CAT scale. Empty trailer was 5600#, rear axle was 15K#.....all good. To my shock though, the steer axle was 15500#(steer axle is rated at 13800#) Half tank of fuel(100 out of 200) and no fresh water, which will add more weight. So far I have found tires to get me to about a 14500# rating and my wheels are 7400# each.

I'm not as worried about a lawful weigh due to non commercial, as I am blowing tires. This truck has nearly a 24' wheelbase, as do similar conversions, so I realize that is the issue. I'm planning on moving the gn ball 2' farther back(total of 3' behind axle) but I'm assuming that will show little gains. How common is this steer weight and should I be concerned from a safety standpoint? Sorry for the long post.

[asitool]

How far is your rear axle center from the rear of the rig? btw...it is interesting to compare part numbers of bearings, spindles, springs, etc on different rated front axle setups.

[neetchracer]

Rear axle centerline is approx. 3' from rear of toter. It's winter time up here, so I won't be digging into the parts of a frontend for awhile, but I will let you know when I find something out. I've been toying with the idea new front wheels and changing tire size to accommodate a higher load, but I don't believe I have enough room in the rear to match a taller tire in front. I'm not so worried about axle hardware as I am the tires.

Sorry if this is kind of a repeat post, but I just now found other threads I have been reading.

[DeepVee]

neetchracer, A few of us on here have been through this. Mine is a long story and started somewhat like your's except I didn't find out until after a blow out on the interstate. I put our rig on a scale after the blow out and found about the same as you, almost 15K lbs on the front axle with a light fuel load. After talking to one of the new Sport Truck dealers I discovered we're not alone and a lot of the new rigs are coming with 18K front axles and tires. We did a full front axle swap on our truck along with new tires and rims to get to an 18K spec. I don't want say this is required but at a minimum you may want to consider switching to a set of 9K (9" wide) wheels and 315/75 x 22.5 tires. You can run the 315's on the smaller (8") wheels but you usually have to de-rate the tires a little. The trash trucks pretty much all run the 18K axles and wheels so this is where we found our parts. I will only run the Michelin 315 tires and replace them every 5-years. You can get a pretty good Michelin discount if you join FMCA.

There are some other tire options a little lighter or heavier but I felt the 315's would have better availability since a lot of the big passenger buses also run the 315's. We switched from 11R's to the 315. The biggest clearance issue was with the steering travel and we did loose some steering travel.

As for the axle assembly, some say these lighter axles are fine and I've heard the 12K, 14K & 16K sometimes use the same parts and just have higher spring rates. It's difficult to get a clear answer on this though. We had a Volvo only front axle under our truck and I couldn't get a clear answer from anyone on it's capacity so we swapped it for a true 18K used Rockwell assembly and then put all new hubs and brakes on. We also added dual steering.

I'd be happy to talk with you if you want or feel free to ask any questions here if you'd like.

[neetchracer]

Thanks, I may take you up on that. I'm good with new wheels and tires, but the extra 2" or so my create an issue getting it into my barn......lol. I'll figure it out. Thanks for your help.

[bushpilot]

As a comparison - We run 275/80 22.5's (on 8.5 inch rims rated at the same 7,400 lbs)

of particular interest our DOOR tag says - 13,888 (f) / 22,700 (r)



But our BUILD tag claims some kind of front Axle mod to 14,600




Moderately loaded (full water, fuel, beer, NO Toad / No Trailer) we tip the scale at - 12,460 (f) / 19,780 (r) -



WITH the 22 foot trailer, race car, tools, full water & beer - we top out at 12,640 (f) / 21,820 (r) -

[neetchracer]

Interesting.

I was just thinking. If I moved my GN ball back 2', I could actually add more bed to the rear and possibly mount the generator (approx 700#s) and the coach batteries behind the rear axle. I'm not concerned with the extra rear axle weight, I'm very safe with that right now. Not sure about water off the rear tires though, I'll have to look into that. I though about moving the fresh water tanks, but that might be a plumbing nightmare......lol.

[38Chevy454]

I had similar issue, but just changed my front tires from 11R22.5 to 315/80R22.5, and the 315's are load range L. I run them on the thinner 8.25 inch wide wheels. This gave me some margin for weight. I did not change the axle or hubs.

As stated, it is very difficult to get a straight answer if the axle and hubs are actually any different. I am sure when you jump up to a 16-18K axle there are some differences.

[neetchracer]

Did you find 8.25" wheels that are rated higher than 7400#s? I don't mind getting new wheels, but I'm having an issue finding wheels that I know will fit. Alot of choices....lol.

[neetchracer]

The 315/80's seem to be about 1" taller. No problem and that's the way I'm going. Just need to figure out 9K wheels now.

[38Chevy454]

I am about 14,400 lbs on the front axle, so 7400 lbs was within my weight limit so I did not need to do any changes. My wheels are the stock Kenworth Alcoa wheels. There are also some psi limits for wheels you might need to be cautious of.

Yes, the 315's are a bit taller than my old 11R's. Did not affect steering clearance or suspension.

If I could find some of the 9 inch width wheels that would be better, but for now I am content with what I have. Being KW Alcoa the holes have a different shape than the std round holes in most Alcoa wheels. I need to check some big truck junkyards, won't be paying KW dealer parts prices for new, that's for sure.

[neetchracer]

My weight slip with an empty gooseneck trailer, about 100 gallons of fuel, and no water or food(winterized)

[38Chevy454]

I think you need the larger wheels with that weight being approx 700 lbs over max. It could also be concerned about axle weight rating.

Just as comparison, my weights are 14,400 front and 20,600 on rears. What is not funny is my front tires are up around 90% of max, and the rears (8 of them) are around 30%. I always load heavy stuff in the rear to help front axle weight.

[neetchracer]

Yeah, I'm actually building/rebuilding this trailer into a stacker and changing alot of stuff. I can move my ball back on the toter 2' with minimal difficulty. I'm also going to move my coupler back on the trailer. I'm not sure what kind of leverage I can get with the ball 3' behind the rear axle, but I plan to find out. I need to do a small amout of sheet metal repair on the rear of the coach anyway, so building up the frame and moving the ball farther back is not out of the question.

[38Chevy454]

I have the advantage that my fresh water tank is right at the back wall, so a full tank gives me a nice weight offset.

[DeepVee]

I ended up buying a set of used Alcoa 9K 9.00's from a garbage truck. They were fairly rough but easy to polish back to life and $80 each. Even though it was some work to get them back & looking good I knew the Alcoa's would be a good wheel. Mine are the standard back spacing and I did loose a little steering radius. As you're probably running into, you can get different back spacings that will push the wheel and tire out a little further. I just decided to deal with the standard wheel and it's been fine so far.

Also BTW, Michelin has some great information on their tires & ratings in their Data Book. Page 75 gives the load capability vs PSI of the 315. Somewhere in there they also denote the de-rating of the 315 if it's mounted on the 8.25" wheel.

http://util.michelintruck.com/databook/DataBook.pdf

http://www.michelintruck.com/referen...nd-warranties/

[neetchracer]

Just throwing this out here. I was talking to NRC today about purchasing some basement doors and brought up the front axle weight issue. I was told they had a GN toter in not to long ago that was very heavy on the front, over 19K. Moving the ball back 6" took 700#'s off the front.

[neetchracer]

Just thought I'd give an update to what I dcecided to do. I went ahead and ordered 295/80R22.5's that are 7830# rated. I will move my gooseneck ball back 2'. If that still does not get my axle weight within the 13880# the trucki s rated for, then I will move the generator and batteries behind the rear axle(approx 1K).

[ChiefMechanicMark]

I know I'm new to this site and a little late getting involved here but I am huge on safety and legality of things. I had a Refuse company approach me with steer tire and axle issues. They had been blowing out tires every few weeks. Now they were breaking leaf springs as well as the new tires were rubbing inner fenders. I weighed the steer axle on the empty truck to find it was sitting at 18K on a 16K rated system. When it was full of trash it was 20K. We discussed options and since trash hauling is what makes the money...I installed a 22K axle with 20K springs and since it already had the 425 tires I didn't have to change those. I also had to adjust the axles stops to keep the tires from hitting the inside fenders and rubbing the springs. The previous repair facility had installed the larger wheels and tires thinking this would take care of their issues.
Always remember...How will this look if I have to stand in front of Judge Judy when things go bad?
Good luck and I hope it works for you.

[DeepVee]

ChiefMechanicMark,

Thanks for the input. This is one of the reasons I went to a full 18K set-up.