Another design
 

In case it helps to get ideas -or to find some defects to avoid- the rack on my XT the previous owner installed: very solid, but heavy as well. The 15y/o panniers are Swiss made, but look exactly the same as the TT (I read somewhere they were actually made in Switzerland). But these ones are hanging on the top bar and then pivot down to insert two screws through the holes on the solid bar crossing from one side of the rack to the other, and then screwed on the back with 2 nuts each. AKA, an absolute pain to mount and dismount (I am thinking on ways ideas to have an easier/safer system, but till now all imply welding...).

Three supporting points: footpegs, handle (?) and blinkers' holes. The panniers lay on a small bed, good to hold them but which to me looks like a blade if you fall at speed with no panniers on... :(

http://i.imgur.com/hJR2g.jpg

http://i.imgur.com/BTrgB.jpg

http://i.imgur.com/RUEFV.jpg

Some painting in the balcony (artificial grass not yet ready to burn under arc welding!) :D

Hope it helps :smartass:

smashed bushes
 

why R the welded spacers stronger than the smashed bushes, OH i get it there us laterial movement on the saddle bag support

Pipe Rack
 

Some nice racks here; I've used a few pix to illustrate a couple of articles on my website.
I was looking to make a platform rack for my GS for the reasons I explain here, then it dawned on me that on one side at least, there's a ready made fixed platform: the silencer.
More details here.

Ch

Good idea but the engineer in me is worried. The single bolt from the V is a pivot point and probably includes a rubber bush. Load the silencer end and this makes a shear force where the pipe enters the silencer. Having destroyed a few silencers by rust and falling off, I'm pretty sure this is a weak spot (because the pipe was bent to shape) and when they go here they leak (because the pipe goes out of round). The vibration will probably cause a fatigue failure even if the actual load is low. I think your idea of adding a clamp round the far end of the silencer and running a bit of tube up towards the indicator is the solution, the pipe then is only loaded in compression and maybe a bit of tension.

If you get time, drill some holes in the channel, less heat conducted and less weight to load that pipe junction?

Andy

Actually, it looks like a one-piece system (or push-in, maybe?) but I agree the pipe couldn't take much dead weight so yes, exhaust clamp is on the way to hook the end up to the subframe. As it is the silencer is rubber-mounted at the pillion footrest so there is some movement there.
The exhaust clamp also makes a convenient point to arrange the the back brace to the other side. Just found a good bit of galvanised flat bar to do that.

Will see how hot it all gets but I'd be surprised if the wood gets too warm plus the ally is only a couple of mm so I doubt much weight would be saved by drilling.

Ch

Try copper
 

Now it's been thoroughly tested, I'll throw this rack into the mix.
Made from 15mm copper water pipe with Yorkshire fittings, it was constructed by the previous owner of my TTR.
Not being sure whether it was at all strong enough for trans-Africa, I thought - what the hell, it looks so elegant, I'll just go with it.
Do you really need heavy steel?

http://i1263.photobucket.com/albums/...64_crop112.jpg
The rack as it came with the bike, moved forward so the front sits on the pillion seat.
Plus Nonfango base fitted.

The jubilee clips that maybe you can see, hold 22mm plain solder fittings (an elbow and a tee), sawn in half and clamped around two joints.
That was my attempt at a bit of strengthening. It looked a mess, so probably wasn't effective, so I removed them before departure.


http://i1263.photobucket.com/albums/...89_crop112.jpg
With second-hand box.


http://i1263.photobucket.com/albums/...23_crop112.jpg
Rack loading, London to Khartoum (photo in Sinai). The Nonfango box is in there somewhere....


http://i1263.photobucket.com/albums/...011825_113.jpg
Rack loading, Khartoum to Cape Town (photo at Cape Agulhas)

20,000 miles in total, including a few hundred miles of dirt, sand and stones in each of N. Kenya, W. Tanzania, and Namibia. Plus bits elsewhere.
Plus the 40,000 tarmac miles the previous owner did, before I bought it.

It's still in use, carrying (slightly less) weight, and no signs of splits, cracks, breaks or anything else you can think of. A credit to the constructor. (ex-British Rail).

Do you really need heavy steel? I don't think so.
Quality of construction is key.

Copper tube, I like it, but would it work on the side holding boxes and dealing with crashes, or even as a platform?

I was looking into doing a similar thing with thin steel EMT (electrical conduit) but it required threading the ends to make right-angle bends - another tool I'd use once. Were it possible, soldering (like copper joints) would have been easier.
Avoiding welding does stir up the creativity.

Oops.... you just beat me to it Chris.

I don't want any flack for omitting this.....
It's right out of sight, so I always forget when singing the praises of this rack.
The pipework is filled with epoxy resin.
It makes all the difference. - Quality of construction.

I had a few offs, fully loaded, in Africa (generally on soft ground).
And more since returning home (green lanes).

But nothing serious - and I hope not to test it along such lines.

I continued the constructor's philosophy for attaching it to the bike, he used only zip ties.
If the rack gets hit, it moves and the zip ties give. (Or break).

When I moved it forward so a lot of the weight was placed on the pillion seat, I reduced the number of zip ties to the minimum that I thought was necessary.
When I inspected stuff on return home, I found just one had broken.

As far as holding anything on the side is concerned - I don't know.
But the entire weight of the Andy Strapz panniers is held by the rack, where it sits on the pillion seat.

So to say the least, I'm pretty pleased with the whole thing.

I have a feeling I've seen the copper pipe rack at the Ace Café Adventure & Overland day, if it was yours I was very impressed. I didn't realise it was epoxy filled though, I wonder how much difference it makes.

Welding always seems to be the bugbear for DIY rack creation, and blokes who'll do a bit of welding for beer money seem harder to come by these days so maybe copper is the answer? Still got to learn how to braze though.

Yes, I like an excuse to have lunch (or breakfast) at the Ace. I think it's a great bit of heritage.
And yes, I think the epoxy filling in the rack makes the whole thing practicable. I don't think it would work without it.

This isn't the only copper-pipe rack, I've seen another a few weeks ago, somewhere around London, but can't for the life of me remember where.

Can copper be brazed? I thought soldering or silver solder were the only options for joining it.
Or does silver solder come under the heading of brazing?
If you can solder with a flame and separate flux, silver-soldering isn't too difficult. But practicing can be expensive.....

I thought the great thing with joining copper pipes is that the joints have solder built into a ring inside - as shown here. From the top picture of the TTR, it looks like those sort of joints were used.

With pre-soldered joints, all you do is link up and blowtorch it - the inner solder ring melts, cools and seals. Even i could do that although perhaps it's not as strong as hand soldered?

If an epoxy resin filling is the key to strength then I wonder if that makes aluminum tube an option and possibly cheaper too? Easy joints here or here (UK)
And copper or ally, could the epoxy double up as joint glue too?

I have done a fair bit of stainless steel handrail / ballustrading that is joined with epoxy and that works very well but uses precisely engineered fittings that have a couple of o-rings to control the glue.

In my opinion, copper tube just isn't up to the job for a rack though; it's too soft and I'm pretty sure that size for size, it's heavier than steel. Easy to work though and might be a way of putting together a prototype.

I use good quality seamless steel tube, with end plates or buckets at fixing points. I don't like off the shelf racks with the tube crushed and drilled for fixings. Easy, cheap but a bit crappy IMHO.

Here's one to throw into the mix........strength for weight, you'd be hard pushed to better wood. Some nice spruce would make a very strong rack :-)

In that case what is your opinion on these hex key joints, BYT?
Am I right in thinking they would need a fairly thick-wall tube not to deform under the screw and so you end up needing unnecessarily heavy tubing?

I think the key with copper is it's easy to join + the resin filling gives the strength as McC has shown. But it might get heavy on a full rack.

I agree. The last OTS bike rack I had had fittings like that. I was rather surprised. Acceptable if DIY but not when paying 220 quid +.

Talking of other materials reminds me of this one - a strap-on plastic platform rack, heated into shape.

Soldering
 

Information

You can solder

• * Steel
• * Stainless Steel
• * Copper
• * Brass
• * even Aluminium (but the solider is expensive and hard to come by)

If you cover or fill the inside of any solder item it will make any repair that much more difficult.

There are various types of solder, some cheap, some with better vibration strength. Best to go cheap as that will be more common in places where you may need a repair.

Failures on most things occur near the ends - you can strengthen the ends by putting another short length of tube side the first. You could solder it there too (to further increase the strength) provided you are not going to brazed or weld it.

Copper is heavier and more expensive than steel. For those reasons most people use steel. Copper can be tempered using heat (just like steel) to make it 'hard' (or stiff in non techinical terms).

The plumbing joints that include the solider will be as strong as those without, they are just more expensive (but reduces the labor cost so cheaper for people paying for labor, and you probable cannot get thoes without solider any maore anyway).

So, would it be possible to use self-soldering copper joints with mild steel tubing? Or would some strange reaction occur (like mixing steel and aluminium)? That might be the simplest solution for the incapable-of-welding.

The perk to copper pipe is that it's easily available, soft enough to bend without tools, cuts easily and there are ready made joints available. If nothing else that makes it very useful for prototyping, more useful than the plastic conduit I've used in the past as it can actually bear some weight which means you can test hang, and even ride with, panniers.

Then once we're happy it shouldn't be too hard to take the copper and get a steel version welded up.

Chris: your image of the throw-over plastic rack...

http://www.horizonsunlimited.com/hub...k-pasterak.jpg

...takes me right back to my square one and thoughts on semi-rigid panniers. Unfortunately I'm one of those people who can see something in their head, but really struggle to translate that into a sketch. I could make one, but draw it? Do you have any more info on it? Type of plastic used etc.?