Mazda CX-5 Forums

Technical Section => Wheels & Tyres => Topic started by: MuddyPaws on May 10, 2018, 01:30:28 pm

Title: Size matters (?)
Post by: MuddyPaws on May 10, 2018, 01:30:28 pm

I contacted my local dealer for a space-saver spare wheel and tyre and was given a 16” wheel with a 145/90R16 tyre. The car has 225/65R17 tyres. The difference in overal diameter is -57mm. This is a negative 8% difference in wheel diameter and way outside the +/- 2.5-3% difference recommended for normal safe driving.

Mazda technical department assure me that the 16” combo is correct and won’t do any harm to the cars trans-axle differentials or electronic monitoring systems.

However, wouldn’t it make far more sense to have a 17” wheel with a 155/90R17 tyre on it? This combo. gives an overall diameter difference of -2% which is within the recommended limits and therefore would appear the better option.

155/90R17 tyres are available from SpeedyWheels.co.uk of Derby as Maxxis M9400S 101M NS. These have a load rating of M101 (81mph / 825 Kg) and are sold as space-saver tyres.

Anybody got any thoughts on this or used the Maxxis tyres on their spare?

Title: Re: Size matters (?)
Post by: Bert321 on May 11, 2018, 07:35:02 am

I bought a full size spare on ebay and lifted the boot floor to suit.

Title: Re: Size matters (?)
Post by: MuddyPaws on May 11, 2018, 08:39:17 pm

I will need to do the same Bert321 when I get towing a caravan as the spacesaver will be no good.