Just wanted to share our experiences on shipping tyres out to meet us on our travels. We are currently in Mauritania on two, heavily-ladden Honda africa twins (hence no Choum route for us) and today took posession of 2 new rear tyres at the airport today.
On the subject of shipping out tyres, we used a firm called James Cargo (email: mark[at]jamescargo.com )
who will take instruction via email, go round to your house and pick up you tyres and them ship them almost anywhere in the world. We opted not to take the spare rear tyres to save hassle but knew we'd need get spares from the uk as the tyres are hard to get. We have done 5,200 miles getting here from the UK and all of the first 4,500 were good road miles. If I did this again I would take at least a spare TKC on the back maybe even a road rear with a TKC on the back).
Point 1 - make sure you get all the documentation printed off BEFORE you go to the airport. No docs, no chance.
Point 2 - we paid to release the cargo forms to the Douane (4000 Oogs) and then the Douane 'took' about 2x the value of the item AND the cost of the shipping printed on the Air France Air waybill. Even with a lot of haggling we saw Eur200 leave our wallet and the invoice even said the tyres were only worth USD85. They obviously see the low invoice values and make sure they get their cut by doing this.
Point 3 - you will not be able to avoid using a handling agent (whether arranged or picked up when we got there) and that was to be Eur80 but I got them down to Eur60. I would pre-arrange the agent and fix costs upfront if poss. Could save hassle but will save money.
Overall, two new Continental TKC80 tyres in hand in NKT,RIM cost us GBP120 + GBP200 + EUR200 + 4000 Oogs (GBP12) + EUR60 = GBP523.
We've committed to doing this again in Cameroon as, like this time, we have the tyres and also a service pack waiting at home so hopefully we can control the cost but it ain't cheap!!!