This thread was started in April 2009.

We’ve all heard apocryphal stories about people who overload their rear carrier and break it. The recommended weight limits do seem to very low and very easily exceeded…

I bought an SW Motech rear carrier and Givi Monokey adapter plate for my Triumph Sprint ST because it looked good and exuded typical German quality of design and manufacture. It wasn’t cheap, with the rack (“Alu-Rack”) coming in at £92.32 and the adapter plate at £25.99 both from Bykebitz in Yateley. This was in April 2007.

The rack fixes to the mounting holes left when you remove the passenger grab rail with some very nice hex bolts.

Here’s what I mean:

The posted weight limit for this setup is 7.5kg

Skip forwards 18 months and I spent 6 months commuting to St Albans which was 50 miles each way (M4/M25/A405). This included carrying a backpack containing my laptop (and my lunch).

The Givi box weighs 4.1kg empty, my backpack containing the items above weighs in at 7.3kg, a grand total of 11.4kg – just a bit over the posted limit then…

One Saturday morning, whilst washing my bike (as you do), I noticed that the box moved up and down very easily – in fact, you could say it looked loose. Loose it was. Actually, the rack had broken on both sides and the whole thing was only held on by a 1/2″ section of steel bracket… (oops!)

Luckily, a local farmer is pretty handy with a welder (he does keep 3 CX500s and an old Royal Enfield / Indian on the road). He welded them up and I was good to go.

For a few weeks.

Another “flappy Givi” experience (this time with photos):

So I stumped up the courage (and the money), went down to Bykebitz and ordered two replacement brackets:

The cost: a mere £54.48 …. (where’s the “gulp” smiley when you need it?)

Anyway. Back, fitted and touring now. I haven’t (can’t) reduce the weight of what I carry, so this story may still have another chapter…

Update 14/12/09: So Far So Good…

The Givi/SW Motech combo is now fitted to my third Sprint ST with no ill effects (so far). I’ve just bought a Givi E52 box which will fit two full-face helmets (and allow me to overload it even more!).

E52 arrives after Christmas.

I will keep an eye on it.

Update 16-January-2012: More Problems

Two years later. Tours of France and Ireland. Sprint ST #4 (a black one this time), and it’s happened again!

Two different problems this time. Firstly, the box is loose on the adaptor plate, largely due to the fact that the “top hat” fittings have worn their way through the cutouts in the plastic on the base of the Givi.

This is the Givi rack and plate from my Honda VFR800. You can see the two “fingers” that fit into the slots in the base of the box.

SW Motech do it differently:

This “tophat” slots into the underside of the Givi box (Note that this picture shows the new modified part – more later). Over time and about 20k miles, this has worn the plastic slots in the box:

You can see the wear around the end of the slot. This caused to box to flap up and down (causing more wear!). I’m sure that any mechanical engineers reading will be familiar with this (I wasn’t) but the soft part can actually wear the hard part (as well as the other way round). Here’s a picture of the old part next to the new one that was fabricated by my neighbour:

You can clearly see the worn aluminium on the left hand part.

Luckily I have a very clever neighbour who is pretty handy with a lathe and he made me up a couple of replacement parts. The are larger than the originals to take up the slack in the worn box.

So far, they fit well and have (mostly) stopped the movement of the topbox.

Next…

As I had a broken rear light, I decided to remove the rack and the rear fairing, only to find that the “new” SW Motech rack was cracking in exactly the same place as before:

Again, mechanical engineers will probably spot this as an example of a stress fracture. Do I remember from somewhere that Royal Navy engineers redesigned the hatches on their warships to stop this? Nice sharp corners = concentration of stress = fracture

What would be wrong with some nice smooth curves…  ?

So now I’m faced with a choice of replacing them again or switching to a (better designed?) alternative system. I will forward this to the guys at SW Motech and see what they say. They still make these racks (4 years on) so must believe that they are OK.

So…

Box refitted and a close eye being kept on the cracks. But it still moves up and down!

Update 25/02/12: … and this is why

The adaptor plate is fitted to the rack with three quick release clips which are very useful for switching plates (never done it) or removing the whole thing (once) – unfortunately, these fixings are not as robust as good old-fashioned bolts…

Here’s the SW Motech rack from underneath:

And here is the offending fastener:

You can see that the seating is worn. The effect of this is to allow the rear of the box to move up and down.

Ordered a new part. Naturally you have to buy the whole fastener which comes in a natty bag from SW Motech in Germany (even though it’s made in China). The cost? £6…

Looking closely at the part and Googling, I discover that it is actually made by Camloc (Part number V50R3-1-1) and can be found on their website. Download the pdf for full details.

Unfortunately, you can’t buy online direct from the manufacturer. Clicking the “Buy Online” link on their website merely lists their three UK distributors who, even though Camloc insist that they offer “our full range of products and accessories“, do not list these parts (and don’t have very helpful “Search” facilities).

I’ve paid my £6 so will fit my replacement part, but if anyone else out there gets any further with buying these, let me know!