Usually in the back if there is no provision underneth, however you can fit/buy a bracket to take the spare wheel, ive just fitted one on a eurocargo right at the back underneth behind the back axle. Speek to your hgv mechanic he should be able to advise you. Oh just a thought but if you dont have a hgv jack, wheel brace and plenty of mussles why dont you just keep the phone number of your local 24hr tyre company in your phone, even if your out of there area they should be able to arrange the closest fitter to come to you. Like I said 'just a thought'.
Darren Brown, December 2010