Hitch mount bike rack

[garfield]

Hi all,
Just wondering if anyone has made their own hitch mount and welded it onto the camp trailer themselves to carry bikes?
If so I'd love to know what dimension steel tube you used and how it finished up.
Thanks
Geoff

[Ben.Archer]

The standard external dimensions of the tow hitch is 50x50, the closest match for a bike rack for the receiver is going to be something like a 60x60x4mm.  You can get closer but you may need to go upto a 6/8mm and this gets heavy. 

Best bet is go down to your local steel supplies place with your dimensions and see what they have that fits as they are unlikely to have every dimension and may have off cuts that could be close enough....

[garfield]

Hi Ben,
Thanks for the reply mate.
I want to make it like the attached pic. Can I buy a size that I can fit another inside it like a snug sleeve? I have a tongue with a tow ball that I want to bolt to a piece that I can slide inside the fixed part if that makes sense. 
Thanks
Geoff

[Beatle]

Yes, your local steel supplier will have a list showing what size SHS (square 'tube') fits inside what SHS and how much clearance you get  Just google "telescoping SHS" and you'll get plenty of hits.  Grab one of the Aussie versions:  http://www.onesteel.com/images/db_images/productspecs/Telescoping%20RHS%20&%20PIPE%20p.pdf

SHS is measured on the outside, so depending what size you want to use, you'll need to play with the wall thickness of the female section to get the required clearance.

Note that specialised towbar manufacturers (e.g. Hayman Reese) use their own tube and it will usually fit neater than general SHS.  You also need to watch the radius at the corners as swapping brands of SHS can mean the size is right, but the corners jam. You'll also need to smooth out any significant seam weld dags inside the female section.

For a bike rack you don't need to be too cute with the fit.  Too tight a fit and it can jam.  Better to use some form of anti-rattle/securing bolt/split tube to tighten it up, or better still, brace from the top of the bike rack to reduce flex and movement.

I recently bought an old Jayco which has a 4-bike rack on the rear, and the rack is tethered with small chain and turnbuckles either side.  It's considerably less flexible that when mounted to the towbar of my Landcruiser in the normal fashion.

50x50 is overkill for a bike rack, but it does keep commonality with most tow hitches.

[garfield]

Hi Beatle, thanks for that mate.
I'll take some pics and roughly put together what I have in mind and post it to see what you guys think.
Thanks for the link and the info you have given me, much appreciated.
Geoff

[Beatle]

I assume you have tools?  Welder?  If you don't, there may be other ways to attach a rack (bolts, so you only need a drill and spanners).

How many bikes involved?   

Where are you located?

That photo shows the anti-rattle bolt directly under the locating pin.  This is the worst place to put it as the tube will still try to pivot around the pin.  Better to put the anti rattle pin underneath, up forward, so it has max effect for minimum force.  On top at the rear may give better protection and access, but on a towbar the rattle bolt marks the hitch tube and forms a 'stress-raiser' from which cracking can initiate.   Better to not have stress raisers between the locating pin and the load cause if it cracks, the tube departs the vehicle   That would make you very sad indeed 

For a bike rack it's probably not worth worying about.

It's highly unlikely a hitch tube would break through, but if you are at the design stage, better to do it properly where practical. 

[garfield]

Hi Beatle,
Yep mate, have a a 180 amp Mig welder.
4 bikes mate, just small BMX bikes
I'm located in Sydney.

Would you please have a pic of where the anti rattle bolt should be located please?
Also mate, would you know why on most of the pics I've seen of these mounts, there seems to be a second layer if you like of steel that forms a thicker lip around the opening?
Thanks
Geoff

[KingBilly]

Pretty sure 65mm x 65mm RHS with a wall thickness of 6mm will accept a regular tow hitch.  I will confirm and get back to you.  No need for the reinforced lip.

KB

[BLKWDW]

Is there a reason people just dont mount up a towbar to the trailer the same as a car. Then you can use a normal car hitch. I'm going to do it to mine when i can find another gq towbar as it fits perfectly on the trailer chassis. Would be stronger then a little peice welding on like in the pic. If bolted on like on a car easily removable as well

[Beatle]

That extra piece is for looks, or maybe it provides a bigger surface are when you smack your shin against it...

ANTI-RATTLE BOLT:  I'll try to explain in words.....

The photo of my current bar shows the rattle bolt at the top right sticking out at 45 degrees. It is aft of the locating pin around which the insert tends to pivot (exaggerated).  This position gives easiest access and visibility, and is the most common spot.  It pushes the rear end of the insert down, the same as the weight of a trailer.    Many tow hitches don't have enough room on the bar to install an anti-rattle bolt here.

If the bolt were in the underside at the rear (or topside-fwd), it would force the insert up and be supporting the weight of the trailer.  The bolts would quickly wear and require constant tightening to remove the slop, it would also wear a hole in the insert. And the threads would peen over meaning you'd never get the bolt out again.

The 'best' spot for the bolt is sticking out at 45deg, but on the lower side and forward of the locating pin.  This still forces the insert in the same direction as the trailer weight.  The further you can get the bolt from the locating pin, the less load it needs to take to secure the insert,  the less movement, meaning less wear and damage to bolt and insert.

Downsides to having the bolt fwd-underneath are access, vulnerabilty to hitting rocks, road etc, and visibility.   But, the groove made in the towbar insert tube will be forward of the retaining pin, so any damage to the insert is not a safety issue.  Some setups have a very short female tube and may not have room to place the bolt under/fwd.

Clear?  As mud??

As to why use a hitch insert instead of a bolted tongue?  It's probably just for ease of installation and removal.  Pull the pin, slide the hitch in, replace the pin.  Ready to go.  But of course by the time you add doing up the rattle pin it may be just as fast to use a tongue.   The slide in hitches are generally rated to carry more load that a tongue, but that's irrelevant for a bike rack.

The slide-in hitch also gives commonality between (most) tow vehicles and trailers so you can easily slip the bike rack into either without removing towballs etc.  In my case I have two bases for the bike rack (I don't have a slide-in hitch on the van just a ball screwed to the bumper), one on the trailer and one on the car. So when I pull into camp and unhitch the van, I move the rack to the car for day trips. 

Still, it's worthwhile to suggest other methods to secure stuff.  Is there any reason to use a tow hitch of any description?  People usually default to tow hitch type setups because most bike racks are secured via a towball.  But you could easily drill a couple of smaller holes and secure the rack base with normal bolts. Or you could use smaller tube than a tow hitch.

[Beatle]

Is there a reason people just dont mount up a towbar to the trailer the same as a car. Then you can use a normal car hitch. I'm going to do it to mine when i can find another gq towbar as it fits perfectly on the trailer chassis. Would be stronger then a little peice welding on like in the pic. If bolted on like on a car easily removable as well

Sorry, I re-read the post and see you are intending on bolting up the entire towbar?   That's a LOT of added weight for no reason, probably reduces clearance under the trailer, and yes it's strong, much stronger than what its bolted to, so that strength is redundant (weakest link in a chain and all that).  Granted that tube on the Skamper looks pretty flimsy, but it's only there for a bike rack (and probably two bikes max) or as a rear pull point.

If you are going to the trouble of adding captive bolts or tabs to the chassis of the trailer to accept a vehicle towbar, it would make more sense to build a complete rear bumper/carrier assembly, correctly mounted to the trailer, and incorporating a square hitch receiver into that.  It would be more versatile than another car towbar (jerry cans, swingaways etc)

[garfield]

Thanks for the replies guys, but I'm a novice at this and a little confused 
You guys certainly know what you are talking about and I appreciate your advice and guidance. I get lost in allot of the technical terms for bits and pieces.

Beatle, when you say "The 'best' spot for the bolt is sticking out at 45deg, but on the lower side and forward of the locating pin." does that mean ignore the pic and put that bolt in the same spot at 45 deg, but underneath the locking pin not above as shown in the pic?
And in the pic, is that connected to a car - not a trailer? is that just to illustrate where the pin and bolt go etc...? sorry for dumb questions mate but I'm not the sharpest tool in the shed when it comes to this stuff.

Is there any pics of one connected to a camp trailer? I have a tow tongue removed from a tow bar of a car only with a tow ball on it. I was thinking of welding a piece of whatever the recommended dimensions SHS were underneath my camp trailer (like in the pic I added) and wanted to bolt the tongue to the sleeve (as the tongue is quite thick and I'm not sure I could really penetrate it good enough to the sleeve with my 180 amp mig)  I then wanted the sleeve now with the tow ball on it, to slide into the SHS welded to the trailer and then attach my bike carrier to the tow ball and hook up the bikes.

Thanks
Geoff

[D4D]

Wow, I thought I had OCD with cleaning and keeping everything looking factory new

[Beatle]

Wow, I thought I had OCD with cleaning and keeping everything looking factory new

  Ha ha, it's an old photo....

Geoff, post a photo of under the rear of your trailer, and of the tow tongue, and of the bike rack if you already have one. It will make more sense if we talk specifically about your setup, rather than in (drunken) generalisations.

does that mean ignore the pic and put that bolt in the same spot at 45 deg, but underneath the locking pin not above as shown in the pic?

  Yes, Put the bolt underneath the tube, and as far forward as possible. But, for a bike rack, the same position as pictured will do the job.

is that connected to a car - not a trailer? is that just to illustrate where the pin and bolt go etc...?

Yes, fitted to an 80 series Landcruiser.  It's "for illustration purposes only"

sorry for dumb questions mate

No such thing as a dumb question.

You shouldn't need the heavy steel tongue.  Simply bolt the bike carrier directly to the male tube section.  You should never need to unbolt it  You can use a towball as a bolt, or drill more holes and use regular bolts.  Bolts might be easier if you don't have a drill/holesaw of the correct size for the towball shaft.

If you have a square hitch receiver on the tow vehicle and wish to also use the bike carrier on the vehicle, simply slide the bolted rack & tube assembly into the vehicle receiver, determine exactly how far in it should go (check clearance of handlebars and pedals to the car bodywork etc) then mark the locating pin holes, remove the assembly and drill the inner tube so you can slide the pin through.  Do this FIRST, before fitting the receiver tube to the trailer.

Then slide your new outer tube section onto the assembly, offer it up to the trailer to determine final position, mark it, drill pin holes to match the holes in the inner tube, and weld the trailer receiver tube in place.  Depending on the structure at the rear of your trailer, you may need to add some strengthening pieces (hence my request for a photo).

If it works out just too hard to match the locating pin holes between the vehicle and trailer fitups, it's OK to drill a second set of locating pin holes in the inner tube.  I'd cut the inner tube section longer than you reckon you'll need it just to give you some room to adjust things.  Once everything works, you can trim any excess tube.

[garfield]

Thanks again Beatle.
I'll take some pics this arvo when I get home mate and post them up.
Thanks 

[garfield]

Hi Beatle,
Took some pics mate. It was late when I got home and a bit dark.... hope you can make it out though.
Thanks
Geoff

[garfield]

Some more

[briann532]

Wow, I thought I had OCD with cleaning and keeping everything looking factory new

I dont have OCD.

I have CDO - The letters are in the correct alphabetical order.......

[Beatle]

So is that two lengths of square tube fairly close together across the back, under the floor?  Or is the rearmost cross support angle?

If it's two SHS and the bottom face is the same distance off the ground (i.e. they are the same size) then that means you have great support structure to weld the outer hitch receiver tube to.  Much stronger being supported both ends than the one on the Skamper in the first pic you posted.

[garfield]

Hi Beatle,
Yeah mate I have 2 pieces of SHS tubing that I can connect to. They are both the same distance from the ground as you say also.
So I'd be better off getting a piece long enough to tack at both ends.

[Beatle]

Within reason, yes I'd try to span the two.  What's the distance?

You don't need to extend/weld the hitch tube across the full width of the forward trailer cross beam.  Simply welding the upper-forward edge of the hitch tube to the lower-rear edge of the cross beam will add significant resistance to rocking/flexing action.  I'd also only weld the points shown in red.  This retains strength of the crossbeams and if a weld does crack, it won't unzip along whole thing.

The problem with a bike rack isn't so much the actual weight of the load, but the large lever provided by the vertical post.  If the hitch tube is allowed to 'rock' back and forth it will weaken the welds.