How to choose
Rim diameter and tyre profile
Rim diameter is measured in inches and has to match the tyre diameter: an R18 rim takes only an R18 tyre. If you fit a larger rim than the factory one, the tyre needs a lower profile. That keeps the outer size of the wheel the same as the original, so the speedometer reads as before and the wheel takes up the same space in the arch. A lower-profile tyre does absorb less of the road's bumps.
Most of the R18 tyres in our catalogue come in the sizes 225/45 R18, 235/55 R18, 235/60 R18.
A smaller rim is not automatically a safe choice either. The brake discs and callipers need room inside the rim, and a smaller-diameter rim can foul the calliper. The car manufacturer decides which sizes the car may use: they are listed in the owner's manual and on the sticker in the driver's door frame. Latvian Cabinet Regulation No. 295 of 30 May 2017 requires the tyre and rim combination to meet the manufacturer's specification and all rims to be the same size, unless the manufacturer states otherwise.
The diameter alone is not enough
Two R18 rims may or may not fit the same car. The bolt pattern (PCD) has to match first: the number of bolts and the diameter of the circle they sit on. The most common patterns on this page are 5x112, 5x114.3, 5x108, 5x120.
Then check the other dimensions:
- Centre bore (DIA) - it must be the same size as the hub or larger. A larger bore is centred with hub centric rings; with a smaller one the rim will not fit.
- Offset (ET) - sets how deep the wheel sits in the arch. The higher the ET, the further inwards the wheel sits. The offset is marked on the back of the rim. The wheel must not stick out beyond the bodywork or touch it.
- Width - together with the offset, it decides whether the wheel fits in the arch and what tyre widths can be mounted on the rim.
- Seat - the seat of the bolt head has to match the seat of the rim: cone, ball or flat. The original bolts often do not suit new rims.
Choose your car, and rims that do not fit it drop out of the list.
Before the tyre is mounted
Some things can only be checked on the car itself. Before mounting, put the bare rim on the hub and turn it by hand: it should spin freely and must not catch the brake calliper. Also check that the bolts screw in to their full length. Once a tyre has been mounted, the rim is no longer in the condition you received it in, so do this check beforehand.