Wheel falls off at +80kph Exciting

[Jedaro]

The MacGregor manual states in bold print:
MAKE SURE THE WHEEL LUG NUTS ARE TIGHT BEFORE TRAILERING THE BOAT and further on states:
LUG NUTS.
It is the owners responsibility to check the lug nuts that secure the wheels to the axle before using the trailerIf they are loose, you may lose a wheel with serious consequences. They should be tight. The proper setting, using a torque wrench is 90 to 95 foot pounds. Dont move the trailer one foot before checking these nuts.

Well another adventure with Jedaro my 26x---sailing is relaxing and forgiving with that boat but trailering--well that's another story. . I had the bearings repacked, wheels tightened, and brake fluid checked in July and had driven only around 150 km. However last week I only did a visual check (a Senior Moment as I didnt have my checklist out) before leaving for a 1 hour trip to Kingston. The right wheel fell off at 85 km per hour on the way down to sail in the 1000 Islands and Lake Ontario. Luckily I was constantly checking my rear view mirror and saw smoke way behind me then I checked my right mirror and I could see the smoke coming from the tire. I was able to slow and stop safely with just part of the left wheel still on the highway. All 5 lugs sheared off and the right wheel was held in by the axle end and the fender. The tire had another ridge in it from the fender edge and I guess thats what kept me relatively stable as well as the tire on (sort of)..
The CAA tow truck driver we called didn't have all the right equipment but he was able to call towing in Kingston. Unfortunately a flat bed to raise the boat would have left the boat so high that we wouldnt have been able to travel under highway bridges. The alternative was to have a portable garage drive out from Kingston. While they were coming out we were able to drag the trailer and boat off the highway by using a sledge. To do this I jacked up the trailer and the wheel promptly fell off. We placed a 6 ft long 4X4 piece of wood directly under the trailer frame so that the axle bolts would dig into the wood as I lowered the trailer. I was able to drive (very slowly) forward dragging this sledge onto the soft shoulder, sweating profusely and taking great care not to have the boat slide down the embankment. My wife and another driver were able to find 4 lugs at a Canadian Tire (that's all they had). By this time the portable garage arrived and the mechanic was able to take the wheel casing off and replace the lugs, tire and rim. I followed the Pat's towing truck back to Kingston where they were able to have the trailer ready for 10 am the next morning with a new wheel and tire. The towing people were fantastic. The cost was close to $600 CDN. We consider ourselves extremely fortunate, as we were lucky not to have had a major accident.
(We had 5 beautiful days at Kingston and the Thousand Islands)

RECOMMENDATION: The mechanic from the portable garage says that this is a frequent occurrence in this area and highly recommends that a torque wrench be used and the lugs checked every hour or two when travelling because if the lugs are tightened unevenly then the loosest can cause vibrations that will begin to loosen the others. The holes in the wheel will wear against the lugs. Finally the lugs will shear and you will have a one wheeled MacGregor trailer.
Hope that my experience will save someone grief.
Mike Purdy
Jedaro

[Harry van der Meer]

You were very lucky not to get in a major accident.

The 1000 island region is certainly very pretty (I used to live in Kingston, and my daugther is currently attending Queens University). I have never sailed in that area but I know that the currents in the St Lawrence seaway are very dangerous.

Question: What is the difference between lug nuts used on a car compared to those on a trailer? I never worry about the lug nuts coming off a car.

[Dimitri-2000X-Tampa]

Many years ago, I had some work done at one of these "cheapie" tire places that hire young and inexperienced laborers to take the wheels on and off. After paying for the work, I drove my '77 Toyota Celica out of there and a few hundred yards down the road noticed an unusual vibration/clunking noise. So I turned around and headed back to the tire place. Found that all 4 wheels had the lug nuts barely finger tight and the wheels were wobbling themselves off!

[Mark Prouty]

Thank you very much for sharing your experience. I didn't check my lugnuts on my last trip. I'll be sure to from now on!

[Chip Hindes]

Question: What is the difference between lug nuts used on a car compared to those on a trailer? I never worry about the lug nuts coming off a car.

I've asked myself the same question. My guess is it's because the lugs on the trailer are way more heavily loaded than those on a car/truck. You've got a single axle, two 14" wheels, 10 each nuts supporting something over 3,000 lbs; the way many Macs are loaded I'll bet it's closer to 4,000 than 3,000. Most car axles carry a little more than half that. Some 1/2 ton pickups & SUVs may be approaching the lower end when fully loaded, but they spend most of their lives empty; 3/4 ton & larger can carry more but they usually have 6 or even 8 lug wheels.

[Dimitri-2000X-Tampa]

It may also have something to do with the fact that most trailer wheels are not balanced (the guy at the trailer shop looked at me funny when I asked this question).

I know that the stock wheels/tires have a lot more vibration which could cause lugs to loosen....however, I have never had one get loose on the 5-6 trailers I've owned. Similar to the above story about my car, I'll bet Mike's problem was that his shop did not tighten the nuts adequately in the first place.

Anyway, I recently got new wheels with Goodyear radials on them from a goodyear shop. The tires were balanced like automobile tires and there is a marked difference to the way they ride....very much smoother. I think the radials "give" more than the bias-ply's did though...regardless of the talk of "stiffened" sidewalls for ST tires. When I look out my rear-view mirror, I see the tires "bouncing" a bit (sidewalls bulging out) when I go over bumps. This probably assists in the smoother ride as well as the balancing. I haven't had it out on the highway yet so its hard to comment on the sway yet...but it certainly did nicely with speeds up to 50-55 on the secondary roads.

[Moe]

I don't know what it is either, but when I was an RV tech, we experienced a lot of loosening, especially on new trailers. Most RV manufacturers insist lugs be retightened after 50-100 miles from the initial tightening, and any time a wheel is removed and replaced. I've usually found more than a few loose.

--
Moe

[Harry van der Meer]

I use a large wheel lug x-wrench (don't know the correct name) which creates quite a good torque. However, I find that after large trips (600 miles or so), I can tighten the lugs a little (1/8-1/4 turn). So they are loosening up......

[Mark Prouty]

All right, all right just a dumb question but why not use these:

Nyloc Nuts

[kmclemore]

All right, all right just a dumb question but why not use ... Nyloc Nuts

Because Nylock nuts are only rated up to 250 degrees... and if you've got surge-brakes on that trailer there's the possibility that the hub temperature could exceed that amount.

A better choice might be 'jetnuts'.


However, in either case, you lose the 'centering' effect of the standard lug nuts. I opt for using a bit of Loctite on the standard lug nuts, myself.

[Dimitri-2000X-Tampa]

I think it would be a big mistake to use anything other than lug nuts. Although they do have the ones that are closed on top which are probably a lot better at keeping corrosion out...to use these, you would need to make sure that the stud is not too long though, otherwise, they would run out of room.

I also think that if you start going much over 100 lbs of torque on these things, you have a good chance of shearing the lug off yourself. I have mine torqued at about 90lbs and they aint going anywhere.

Talking about centering a lug nut, one mistake that is probably made frequently is having the wheel "slightly off" when tightening the nuts. Ie, if the wheel is being artificially held off the brake drum a tiny bit due to the angle of the wheel, etc, then you might not be tightening the lug up against the true stop. One good way to screw this up is to let the jack down while the nuts are still finger tight, then trying to tighten them up the rest of the way. I expect that this is why so many manufacturers recommend checking the nuts soon after leaving the shop or wherever you took the wheels off.

What I do to avoid this is to make sure I have at least 20-40 lbs of torque on the nuts while the wheel can still freespin (still up on the jack). You will notice that this is the way the professionals do it also..when they use air powered wrenches (my little consumer grade impact air wrench doesn't have enough torque). To keep the wheel from turning while tightening, I will jam a 2X4 into the gap between the tire and ground (concrete slab). That way, I can get them fairly tight before lowering the jack...this will make sure that the nuts are well centered in the holes and you have put the wheel all the way up against the brake drum. After getting them pretty tight like that, I will lower the jack and get the rest of the 85-90 lbs of torque on them since you need that extra friction to get the final torque in.

[Chip Hindes]

I believe it's more complex than most are assuming. My own gut feeling is that the primary means of loosening; the intial failure mode, as it were, is not the nut backing off the stud, but that the material on the wheel and nut are actually yielding under the stress. Of course, as the material yields, there's less friction holding it on, and it will begin to back off.

This is why, after you've retightened them several times, you don;t have to do it again.

Here's another way you could tell. Loosen the nuts, retighten, then mark the nuts and on the wheels for their angular orientation. Then drive a ways, and check. If I'm right, the nuts will not have turned, but will still require retightening. I'm going to try it on my next trip this Thursday.

[tlperrine]

I lost my wheel on I-70 going about 35 mph. Prior I had heard a thumping sound in the back somewhere. I thought it was a u-joint going out on the jeep cherokee. Prior I had pulled over after going 55 or so. I had heard it for a mile or two. I looked around the trailer, vehicle, etc. so nothing wrong. The road was so busy and not many good places to pull over, it being in the mountain section from Lake Dillon to Denver. No safe place to check it out. So I decided to pull off at the next bext off ramp going up Floyd Hill, about 1 mile away. So I limped up going 35 mph or so. Sure enough looking in the rear view mirror, it dropped off the trailor, and sent the trailor clanging down on the interstate. Scared me to death and sent the free wheel racing down the off ramp. I was lucky I did not cause an accident. This was in my first year of trailoring the Mac. Needless to say I check my lugnuts on a regular basis. It is now a ritual every time I stop. So please check them, I made a big gouge in the road and surprized I didn't damage the boat. It was not fun pulling it off the road. I had to take the next day off to repair it. Just my experience, one to never forget. Terry

[Don T]

Hello:
Please be advised that too much torque is just as bad as too little. Also, the lugs and studs should be free of rust so you get a proper torque. The 3500 lb trailer rating is dictated by the tires then the hub / wheel mounting. To increase the mount stability you could use a ring under the lugs to help spread the force. Over torqing will distort the rim and actually cause failure. It can also stretch the studs, weakening them. Rust will make it feel like the lugs are tight when in fact there is not enough pinching force. The rim will flex and fatigue the assembly. If you watch the rim when you are tightening the lugs you will see it distort when reachng 120 ft/lbs. Uneven torque will cause flexing on the road, fatiguing the studs / wheel. Also, the running temp of the assembly on the road will greatly affect torque retention as it cools and reheats. I use a torque wrench and tighten my lugs to 100 ft/lbs and have never had one come loose or fail. I check them often because they run so close to their design limit.

[Frank C]

.... I use a torque wrench and tighten my lugs to 100 ft/lbs and have never had one come loose or fail. I check them often because they run so close to their design limit.

Don's phrase may be the watchwords of Mac trailering. The factory-installed tires suffer the same stress - they are running very close to their design limit, they are probably the weakest link on the Mac trailer.