I think you need to take a tape measure out and see where they actually differ they are probabley the same.One note of caution if you fit winter tyres or all season tyres only very few are actually better than good summer tyres and in fact are extremely dangerous in use other than on snow on some tyres the wet stopping distance is almost double that of good make summer tyres .In recent tests from the ADAC and TUV in Germany only four makes were actuall recommended with Dunlop being the best.I have new Goodyear vector all season tyres which came in the top four but that was more by luck than management on my part.

Thank you for the warning on winter tyres. The reason for my embarking on this venture is that a visit to Switzerland will place me vunerable to their law which is - in winter, no winter tyres, accident, your fault. As well as vunerable to their weather. The whole business seems a nightmare and I will look into the Goodyear Vector solution.

Thats a bit of super info.

>> I have - 6JJ x 15H2 and 6J x 15CH.

Read this: www.carbibles.com/tyre_bible_pg4.html

About halfway down: H, H2, FH, CH, EH and EH2 : Hump profiles.

Thanks for the info and the link. Unfortunately, there is little to indicate if there are any penalties for mixing H2 and CH. Probably not, but my over cautious attitude to these things will dictate I should use four the same.