Hot Hub

[NiceAft]

Last summer i trailered NicAft almost 300 miles (482km) up to the mountains of NY State. I check the hubs along the way, and the starboard wheel hub was very hot. It did it take more grease, so I proceeded. The same thing happened on the way back. It sat in my drive way for two months. I finally trailered NiceAft to my boat mechanic last week for winterization of the motor and to check out the bearing. Today the mechanic got back to me. He said he could find nothing wrong, but my description made him want check further. He contacted a trailer guy he works with, and was told that the external temperature can get as hot as 300degrees F (148.8c), which is definitely too hot to touch. The mechanic also checked to see if the grease was cooked, it wasn’t.

I will bring the boat home on Friday, and again place my hand on the hub. My old mantra of feel the hub to find either it’s hot or warm; with hot being bad, now may not be correct. I am still more comfortable with warm.

[socalmacer]

Hi,

You did not mention if you have drum or disk brakes on the trailer. Either could be a factor to the increased heat. I have stainless steel disk brakes on my trailer and after sitting for the off season (these are 304 SS) they will build up a thin corrosion layer which will tend to add friction (heat when driving). I will resurface at the beginning of the season which does the trick. Drums I found to have a worse corrosion problem but tends to be unseen, Prior to the conversion to SS rotors, I would get maybe 2 to 3 seasons out of the drums due to corrosion - heat was an issue which I monitored. Anyway, I would put the trailer up on jacks and make sure the wheels turn freely. I would also apply the brakes while up on jacks to make sure the brakes are being applied to both wheels evenly. Good luck.....

Brian
since 1996!

[Russ]

Before trailering my boat this year I added more grease until I saw it coming out of the bearing buddies.

Got to the lake and one side had grease splattered on the rim. I didn't notice until later and everything was cooled down.

I just don't know much about how to grease these things. What is too much, not enough?

[kenfyoozed]

Double check your tire pressure. My pontoon trailer, if 5psi low, will create to much heat as well.

[NiceAft]

I do make certain to check grease levels. There is a blue ring that expands when there is enough grease.

As to the brakes, I’ll have to figure out how to check this out. Checking the brakes is not something I have ever done.

[kurz]

I dont see any reason why bearings shall get hot.
I one time had one that had increased temperature.
The reason was a braking cable that was not easy to move anymore.

[Jimmyt]

Brakes dragging would be my first guess. The wheels should turn freely. If you can't put your hand on the bearing buddy or hub after driving, something is wrong. I disagree with a bearing operating temp of 300 deg F, unless you are doing a lot of braking. A few miles of steep downhill grade, applying brakes the whole time will cause heating.

Also, the fact that one wheel is hotter than the other (which your post seems to indicate) throws up a red flag. Either one side is sticking, or one side isn't braking at all.

If you have an infrared thermometer, drive it a bit and check both hub temps. They should be within 5-10 deg F of each other; and nowhere near 300 deg F. In any event, you need to put a number on it. The fact that you can't keep your hand on it, is not an indication that things are amok - if you were braking a good bit. 175 deg F is one thing, but 300 deg F is a whole different animal.

I would jack each side up and give it a spin test. Apply the tongue brakes, verify each wheel is braking; release the tongue brake; and verify the brakes are releasing. Excessive caliper corrosion should wear off after a few miles/stops - unless it is very bad.

Not sure what you told the mechanic to do, but if you told him to check the bearings and brakes, I'd find another mechanic and get a second opinion.

[NiceAft]

Good info. Jimmy.

[kmclemore]

Ray, I’m exactly with Jimmy… he’s spot on. Who told you that they should get hot - Philly Boat? Because that’s absolutely not correct. A trailer with correctly functioning brakes, driven properly (no stop-and-go driving, no fast stops, etc.) should be only barely warm to the touch after a good long run.

Since the tires are properly inflated and there’s plenty of grease, only one of three things can be happening - bearing is adjusted too tight, bearing is failing, or brakes are dragging… there’s really not much else that can cause heat like that.

I’ll be home in a week - we’re up at the lake presently. If you’d like I can swing by and give it a look.

[dlandersson]

Just a heads-up. Any time I am towing my X, I (learned this in the Army), pull over at least once an hour and check the trailer, feel the hubs. Most problems "build" into a catastrophic failure.

Last summer i trailered NicAft almost 300 miles (482km) up to the mountains of NY State. I check the hubs along the way, and the starboard wheel hub was very hot. It did it take more grease, so I proceeded. The same thing happened on the way back. It sat in my drive way for two months. I finally trailered NiceAft to my boat mechanic last week for winterization of the motor and to check out the bearing. Today the mechanic got back to me. He said he could find nothing wrong, but my description made him want check further. He contacted a trailer guy he works with, and was told that the external temperature can get as hot as 300degrees F (148.8c), which is definitely too hot to touch. The mechanic also checked to see if the grease was cooked, it wasn’t.

I will bring the boat home on Friday, and again place my hand on the hub. My old mantra of feel the hub to find either it’s hot or warm; with hot being bad, now may not be correct. I am still more comfortable with warm.

[dlandersson]

Ok, I dunno about this. Not true with 65 ton main battle tanks, don't see it for 3.5 ton Macs.

and was told that the external temperature can get as hot as 300degrees F (148.8c), which is definitely too hot to touch.

[Be Free]

Hubs can be warm but they should never be hot. If they are hot there is something wrong.

All hub heat comes from friction. It may be friction in the bearing, the brakes, or the sidewalls of the tires but in the end it is friction.

If there is a significant difference in the heat of different hubs then there is a problem in the hot hub. All of those tires are running on the same road surface at the same speed carrying (effectively) the same load. They should all be approximately the same temperature (cool to warm). Any that are hot are having a problem and any "mechanic' who says differently is wrong.

When you are checking the temperature of the tire sidewall, hub, and brakes always start with the back of your hand. If you can feel significant heat radiating off the item then it's probably hot enough to raise a blister if you touch it with your hand. If it's not significantly hot go ahead and touch it to get a better idea of the relative temperature of each item.

Hot tires (sidewalls) are usually a sign of an underinflated tire. If done long enough you will also notice the inside and outside edges of the tread wearing faster than the center. Over inflated tires will wear the center first but they don't usually get hot. Under inflated radial tires are more likely to suffer tread separation as well.

Heat coming from the brakes (rotor or drum) is caused by a dragging brake or excessive braking. A single hot brake is probably dragging. All brakes or all the brakes on the same axle hot is probably caused by the driver riding the brakes.

A hot hub can come from several causes.

• Lack of lubrication.
  Too little or under-performing grease allows friction in the bearing hub causing heat.

• Rust on the bearing surface(s).
  A trailer that sits a long time without moving can collect water in the hub which allows rust to form on the parts of the bearing that are at the bottom of the wheel. The rust increases the friction leading to heat.

• Over tightening the axle nut.
  If the axle nut is too tight then the bearing will be pressed too tightly to the spindle increasing friction which leads to heat.

• Worn out bearings or spindles.
  Properly lubricated and serviced both will last (almost) a lifetime. Unfortunately, very few trailers are properly lubricated and serviced (mine included). It's too easy to say, "I'll repack that bearing before the next trip. A few more weeks won't matter". I usually get five or six years or so out of bearings (in mostly salt water) and a multiple decades out of the spindles.

Bearing Buddys (and their generic offspring) are not a substitute for proper servicing. You still need to take that hub apart and repack the bearing. You need to check the bearing and spindle for rust and pitting. It's much better to deal with a small problem in your driveway than have a failure of any size on the highway.

Russ (any anyone else who is wondering): Pump the grease in your (insert name brand here) until the disc is just short of touching the top of the hub. You are compressing a spring that is going to push that grease back down toward the bearing over time. If you "bottom out" the disc then you are just increasing the pressure in the hub. Too much pressure and either the (insert name brand here) will come off while you are going down the road or the grease will come out of the back of the hub through the oil seal (making a mess all over the bottom of your boat and the back of your wheel. The end result is a bearing with no grease and a serious problem.

[NiceAft]

Ray, I’m exactly with Jimmy… he’s spot on. Who told you that they should get hot - Philly Boat? Because that’s absolutely not correct. A trailer with correctly functioning brakes, driven properly (no stop-and-go driving, no fast stops, etc.) should be only barely warm to the touch after a good long run.

Since the tires are properly inflated and there’s plenty of grease, only one of three things can be happening - bearing is adjusted too tight, bearing is failing, or brakes are dragging… there’s really not much else that can cause heat like that.

I’ll be home in a week - we’re up at the lake presently. If you’d like I can swing by and give it a look.

1st. If I gave the impression that I was told the brakes should get hot, I apologize. What I was told was that that hubs could get hot up to 300F, and not worry about damage to the bearings & grease. Philly Boat does not do brakes. Al just took it upon himself to inquire a trailer dealer.

2nd. I would be a fool if I turned down that offer Kevin.

I’ll make one of my own. When you do come over, bring Jana, and we will put something on the grill and place some wood in the pit

[kmclemore]

2nd. I would be a fool if I turned down that offer Kevin.

I’ll make one of my own. When you do come over, bring Jana, and we will put something on the grill and place some wood in the pit

Such a deal! Ok, we’ll make it happen.

[Be Free]

Ray,
It's true that 300 degrees is not going to hurt the hub, bearings, or grease. The problem is that the hubs, bearings, and grease should not be anywhere near that hot on your boat trailer under normal conditions. If any part of your hub, wheel, or spindle are too hot to keep your hand on indefinitely then you should find out what is wrong.