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Tyres

The widest tyres which fit between the front legs and the swingarm of an R1 -even if they have a much larger diameter than the original ones, which make them roll a lot easier over obstacles and give them more carrying surface- turned out not to bring sufficient carrying capacity on sections of the polar ice with less compact snow. Especially the rear wheel sank in it and in most of those occasions it only found enough grip after the studs got to the polar ice surface.

• The rear tyre should be approximately 60 cm wide. For the front around 40 cm will be sufficient.
sufficient.
• To benefit the steering of such a wide front tyre I am in favour of one which has a bulging tread over its width.
• The tyres are preferably developed for vehicles that ride in snow or mud.
• The more pliable the tyres are the better it is, because in combination with reducing the pressure, it brings you the best grip and especially more carrying capacity.
• In contrast with the wish to have pliable tyres stands the fact that the tyres will need to have several ply because the ice ridges can be razor-sharp. That became clear to me after I heard what happens with 4-wheel-drive cars that set out on the polar ice around Barrow. Regularly they blew a tyre to pieces, especially when their speed was high.
• The tyres must be suitable to use in temperatures around -40°C.
• The existing profile is of less importance, as there can be put on a suitable tread.