Trailers by Indespension

[CreakyDecks]

A bit of research later. The axle was rated 1600kg. This was hard to determine since the marks on the plate were invisible. I reckoned with the boat full of fuel, batteries, anchors and my protable concrete mooring and other junk it was nearer 1900kg. I don't think that was the reason for failure but it didn't help. It seemed to me that the rig would be better off with twin axles. If this ever happened again there would be some redundancy and any way at that sort of weight it would tow a lot better on 2.

1900kg is nearly 4200lbs. If you pumped your tyres up to 40psi on a single axle trailer that would need a contact area of 50 square inches on each tyre. To my mind, on normal sized wheels, that is asking for trouble. On a twin axle it would be 25 sq in each tyre which seems much more sensible. I think this is why so many boat trailers get "punctures". They aren't really punctures at all, the tyres are deforming so much they overheat.

 

[michaelh]

Well it did bounce a bit which worried me. They are 19 inch rims with transit tyres and I used to put about 50 psi in. Its much more relaxed with twins.

I giuess the original owner, who had the boat on a dry stack and didn't ever use the trailer, just specced the cheapest trailer option that was legal.

 

[Red Admiral]

Not one person that I know or at the Academy after launch said hey quick after the launch lets all take off the hubs and clean and regrease them.

You have written about the Academy and I wonder what sort of institution it is - not a sailing or water sports centre, I trust. If it is, there would have to be serious doubts about its competence if staff have no idea about a matter as commonplace as the correct use and maintenance of trailers or anything else to be immersed in salt water, one of the most corrosive liquids on the planet!

 

[Avocet]

1900kg is nearly 4200lbs. If you pumped your tyres up to 40psi on a single axle trailer that would need a contact area of 50 square inches on each tyre. To my mind, on normal sized wheels, that is asking for trouble. On a twin axle it would be 25 sq in each tyre which seems much more sensible. I think this is why so many boat trailers get "punctures". They aren't really punctures at all, the tyres are deforming so much they overheat.

You can carry 2 tons on a single axle if you use "Transit-type" wheels and tyres. I know several 3.5 tonne vans with a 2 tonne maximum permitted axle weight on single tyres. pressures are nearer 80-odd PSI though. That said, I absolutely agree that 4 wheels would be better

 

[Sailfree]

Talking to another competitor at an event he insisted that once his Aston Martin got to 100mph the aerodynamics of a fireball lifted the trailer off the road. Zero axle load.

 

[Rigger Mortice]

I agree that the trailer manufacturers should supply handbooks.

When I bought a trailer a few years ago, no handbook came with it. So I asked for one.

I agree with the earlier comments that we should take at least some responsibility for ourselves. We can't expect to be spoon fed with everything.

 

[Jim@sea]

What i have noticed here is some people dont bother greasing there bearings after every use. Bearings should be re greased after every dunking pushing the water out . I have never had a bearing go on me with this method.If you have plain grease caps with the weep hole in the centre and cannot be bothered getting covered in grease all the time go onto ebay and buy a small packet of M6 grease nipples,a pack of shallow m6 nuts(stainless pref)and a grease gun with app cartridges £20.Use the weep hole as a pilot for a 6mm drill bit put the grease nipple through hole withe nut on the back and tighten it should not hit the stub when putting it back on,if it does just grind a little off of the nipple threads.Then just pump grease in till it is coming out the rear of the hub repeating as soon as poss after they get a dunking. other then that just make sure there is no exess movment 6 to 12 and 3 to 9 oclock.

Absolutely. What I do is when I get there and before my boat goes down the slipway I grease up the grease nipples. then after I launch the boat I grease them up again. Then again when I get home.
And regards bearings, I thought that with my boat Trailer being French I would have trouble in getting spare bearings. So I took them off, took them to a Bearing Shop and matched them for £15 (two bearings and an oil seal)
Aparrently 90% of boat trailers use the same hubs.

 

[fifi]

You have written about the Academy and I wonder what sort of institution it is - not a sailing or water sports centre, I trust. If it is, there would have to be serious doubts about its competence if staff have no idea about a matter as commonplace as the correct use and maintenance of trailers or anything else to be immersed in salt water, one of the most corrosive liquids on the planet!

Good point - I did think that myself. It is a boat building school, woodwork and GRP not actual sailing. But I do think this ought to be part of the course. We did galvanic corrosion but absolutely nothing on trailers or hubs etc which is very different. I have already written to them to ask for their take on things, still awaiting a reply!!!

I can see the point about things getting more expensive. But this really could have so easily been a real disaster on the road. Learning the hard way financially is one thing but causing a pile up I shudder to think.

 

[halcyon]

The hope being that the first manufacturer who brings out genuinely "waterproof" bearings / brakes will be able to charge a premium price for them.

Back in the 1970's I worked on trailer axle design at a firm in the Midlands, we supplied around 70% of the boat trailer axles then. At the time thet had waterproof bearing caps and suspension, and if fitted with disc brakes they were basically water proof as well. Yes we have been there and done it, and thrown the T shirt away.

Axles with taper roller hubs should not be full of grease, it's causes bearing to run hot. After launching the hubs should be removed, brakes washed with fresh water. Bearing should be cleaned, and the only grease should be pushed between the rollers. Any other grease does no work, also the grease seal will stop grease coming through, if you get grease throgh you probably have a faulty seal.

Brian

 

[Lakesailor]

Quite agree. I've just refettled my launching trolley. (not used much on the road, although it is legal) I'd happily tow it around all the time. Think about your car. The trailing rear suspension on most cars never gets greased.

This is the grease I put on the inner bearing.

and this is the amount I put on the outer. None in the dust cap.

 

[gljnr1983]

Brian[/QUOTE Axles with taper roller hubs should not be full of grease, it's causes bearing to run hot. After launching the hubs should be removed, brakes washed with fresh water. Bearing should be cleaned, and the only grease should be pushed between the rollers. Any other grease does no work, also the grease seal will stop grease coming through, if you get grease throgh you probably have a faulty seal...........................................................................................................................I dont know how to space the quote from post. If taper bearings were not supposed to be packed full that would mean the hubs Lakesailor has pictured are no good .The hubs pictured pack full of grease between the 2 bearings forcing grease into the bearings when rotated.

 

[Beyondhelp]

How does too much grease produce friction and thus heat?

 

[aquaplane]

How does too much grease produce friction and thus heat?

I don't know that it does. I do know that you aren't supposed to fill them solid.

I work grease into the two bearings and add just a bit more, like Lakie's picture, and that's enough.

Grease is thick so if there is too much moving round it will cause more drag and heat, not friction and heat.

Grease is probably a poor conductor of heat too so any heat produced won't be able to get away.

Sometimes it's best to just accept that some folk know more than we do and follow their instructions, especially when you have tried it and it works.

 

[Beyondhelp]

Drag is friction. The viscosity of the grease itself is essentially friction. Basically I can't see the logic behind that too much is specifically bad other than leaking past the seals. With the bearing savers I had on my old indespension hubs they were intentionally filled with grease and pressurised so that water could not get in. They worked a treat.

I think it should be said for those who have been talking about it, that if you test your wheel bearings and they 'rumble' even a little bit, they are knackered and need replacing. They should be totally smooth anything less is pitting to the bearing surfaces, and thus failure will occur shortly.

 

[gljnr1983]

Any excess grease should push through the weep hole within the first mile or 2 .I would rather grease in my hub than water be it fresh or salt and this method has lasted me well getting more than 4 years from a set of cheap ebay bearings .Also i have noticed that the rubber bearing seals are more hasle than they are worth because they hold water in the hub when they fail giving you an unexpected bearing meltdown espesialy if you think you can get away with not greasing them every time they are dunked.

 

[Lakesailor]

If taper bearings were not supposed to be packed full that would mean the hubs Lakesailor has pictured are no good .The hubs pictured pack full of grease between the 2 bearings forcing grease into the bearings when rotated.

I don't understand what you are saying.
In the picture the bearing race is packed with grease. There is a bit on the shaft. The other bearing is packed with grease. The gap between them is empty and there is no extra in the dust cap.
You can see a grease nipple on the hub which would pack grease into the cavity between the bearings. I never use that. Instead I take the hub off and put grease in manually if it needs some. Better to wipe away contaminated grease and refresh rather than to just add more grease.
If the hub is full of grease within a few miles it will have warmed up and squirted out of either the hole in the dust cap if there is one or blown past the grease seal.

 

[VicS]

I don't know that it does. I do know that you aren't supposed to fill them solid.

I work grease into the two bearings and add just a bit more, like Lakie's picture, and that's enough.

Grease is thick so if there is too much moving round it will cause more drag and heat, not friction and heat.

Grease is probably a poor conductor of heat too so any heat produced won't be able to get away.

Sometimes it's best to just accept that some folk know more than we do and follow their instructions, especially when you have tried it and it works.

Absolutely.
The work done in churning the grease around is converted from mechanical energy into heat. Cast your minds back to your early science lessons and Joule's experiment to determine the "mecahnical equivalent of heat"

I'd put more grease in than L.S. suggests but no more than half fill the free space between the bearings (which is the amount my car workshop manual stipulates).
If a hub is overpacked the grease overheats and breaks down and you end up with something more like a thick, dark coloured oil. Been there, done that, got the Tee shirt!

 

[Bilgediver]

Experience is a wonderful thing. Indeed I can see that you guys are aware of the problems that immersion brings.

I can't believe that the trailer did not come with some paperwork. I am not completely stupid I know salt corrodes but I did think a marine road trailer would be up to somewhat more than it has been. As per the sale of goods act - it should last a reasonable time and in the absence of instructions it has not lasted.
.

Our Indispension came with a plastic sleeve containing instructions and also reference to washing out the brakes after sea water immersion. I will have to see what bearings are fitted but would probably fit sealed races if not already fitted to give added peace of mind.

Indispension actually do a brake flushing kit to be used on trailers that get dunked which allows fresh water to be used to clean out the drum areas.

It is bad practice to over fill with grease where high speed journeys are possible as yes the bearings can overheat and may not run cool when all the excess grease has melted and run out over the brakes and wheels Especially if leaky grease seals.

 

[SHUG]

The missing item could be the Indespension "Fresh Water Brake Flushing Kit" part number ISBR231.
Its a simple arrangement which allows you to connect up to a hose and rinse out the brakes and hubs.

 

[Lakesailor]

Except the Coaster Swing Mini doesn't have brakes.

You can't flush the bearings out. If you could you'd have to repack them anyway.