Older caravans certainly have 175 tyres fitted to 4.5j rims so you should be ok to fit them. The danger of fitting tyres of too large section is that sidewall could chafe on rim edge but you should be ok with 175s on a 4.5j. You could measure your existing rims if they have slots. Just stick a tape measure through the slot to measure width across rim to check whether 4.5inch or 5inch.
If you want to change all 3 tyres to 165s I can't see a problem provided they have sufficient load rating. You would need commercial van tyres 165/80X13C.
www.mytyres.co.uk click on light truck tyres on the left menu then enter size
www.lovetyres.com none listed on web site, you will need to phone them.
www.oponeo.co.uk click on van tyres under vehicle type then enter size
I have used mytyres several times with no problems, delivery is usually about 7 days. make sure you enter deld only as it may be difficult for their partner fitters to fit caravan tyres unless you ask the fitter if they will remove wheels from a caravan and fit tyres (local fitter partners can be found from the web site) before ordering the tyres. Hope this helps
Hi GCMS2012, I have a spare wheel with the tyre size you quote, its a 4 stud fitting if it`s any help I`m mid way between Newcastle and Sunderland [don`t support either team ha ha]
Hi GCMS2012, checked details this morning as follows, stampted on wheel centre 5Jx13 CH, N25 22b, there are 8 oval holes around the rim, PCD 100mm, email me for any further help terrypricey_1 at hotmail.com
Hi GCMS2012, checked details this morning as follows, stampted on wheel centre 5Jx13 CH, N25 22b, there are 8 oval holes around the rim, PCD 100mm, email me for any further help terrypricey_1 at hotmail.com use the "at" symbal