General

Basic technical data you can find in the Volvo brochures and in the owners manual on the pages 9 and 26. The Volvo C303 must have tyres with a load index of 4PR or 4-Ply, that means for layers of strengthening material in the tyre. The more heavy C304 or C306 must have 6PR or 6-Ply. The dimensions by fabric are 280/85-16 what is 8.90-16 on a 7,5 inch wide rim with 8 holes and 16 inch diameter. The middle diameter for the circle of 8 holes is 222,25 mm or 8,75 inch. The rim is drivable with tubeless tyres as well, if the air pressure is not too low.

Here the original pressure table for the TGB:

In the real world it has been driven very carefully down to nearly 1 bar in terrain and up to 3 bar on the highway as an opportunity to save a little bit fuel.

Important is the picture in the owners manual on page 26, what shows that the tyres which may have a designated running direction should not - as I would assume - be mounted all in the same direction, but on the rear axle in the designated direction and on the front axle in the opposite direction.

As I now until now the original tyres are not on stock or available as new tyres. There are only unused old tyres or allready used ones. Alternative sizes are 9.00-16 or 255/100-R16, which will have a slightly bigger diameter.

GoodYear

The GoodYear studded sure grip tyres in the original dimensions is the most common type of tyres for the Volvo C303. Pictures in the owners manual show this tyre. The traktion in terrain is reputed not to be the very best, but on the pictures from Johan Jans van Bockrijk und Johan Oosterbosch going trial I can see these tyres in action, so this opinion may be very relative. You can change to Trelleborg on the front axle later, if neccessary.

Frustrating in this case ist the german buerocraty: With the MT117 there is from Silverstone in Malaysia quite an equal replica of the GoodYear tyre. But the naming changed from 280/85 to 285/85 - not the real dimensions - and for the new labeled tyres you have no approval in germany - but in the rest of the EU. This is much more unbelievable as the original GoodYear, which was the blueprint, came from Malaysia, too!

From 2007 on this tyre is available with both labels on it: 280/85 AND 285/85 - and there should be an EU-approval as well.

See on the left my totaly worn down spare tyre, which will be changed in spring 2006 against a better one.

Viskafors

On the rear axle my own C303 runs an exotic tyre: the Viskafors Terrain, shown on the right with a pattern for the road allso - the continous zig-zag-line is very well on asphalt. This tyre was available from Firestone for some time as well. Mine have a load index of 4PR, only, and are worn down so much that I have to change them in spring 2006, too.

Trelleborg

A quite more modern tyre than the two before is the Trelleborg Cross Country 153. The pattern is extremly good for terrain, the tyres have the more modern labeling for the load index of 113L and a marking for M&S, too.

Being very usefull in terrain this tyre may use more petrol and be more noisy than the others - I assume. These Trelleborg tyres you can still find today at blocket.se

GoodYear MT3

In the Volvo Catalog on Page 14 are some vehicles shown with an other kind of tyre pattern. I did long time research until I have found a TGB1314 in an offer on blocket.se. The offerer Morgan was so kind to send me some pictures on request. Many thanks.

It is the GoodYear MT3 with the original dimensions for the TGB: 280/85-16 with 6-PLY rating, to be used for the 6-wheelers as well. Having a straight rubber belt in the middle of the pattern it may be a little bit better for the normal road with enough pressure.