Correct suspension springs for tyres


I wonder if anyone can help me.

I have a 2007 Mk3 2000cc sport convertible.

One of the rear suspension springs has broken and needs replacing.

The car has 17inch tyres but when I gave MX5 Parts the chassis/VIN number (looking at their website there seems to be different springs for 16inch and 17inch tyres and they reccomend that the chassis/VIN number is the best way to decide which springs are appropriate) they said that I needed springs for 16inch tyres.

So, I assume that a previous owner replaced the 16 inch tyres with 17inch; but the springs are presumably original.

My questions are a) is it OK to replace tyres in this way b) browsing the Internet it looks like the overall wheel size (wheel plus tyre) is actually pretty similar with both sizes of tyre so why are there different sized springs c) does it really matter which spring I use (in case I put in the wrong ones) d) does buying ones for 16inch tyres sound reasonable?

I’m also going to replace the shock absorbers. Once again MX5 Parts have two different items depending on tyre size. However, my local auto shop, whilst also having two different sizes of spring, only had one size of shock absorber. Does anyone know why the difference?

Finally, when replacing the shocks/springs are there any other items (e.g. bushes) that would need replacing?

Any help appreciated.

Many thanks,


Hi Simon, interesting questions. Easiest would be just to replace like for like based on your VIN. The car, presumably, has been in your hands for a while and no noticeable issues with 17" wheel and tyre set up? However, if it is a 2.0 sport, it would always have had 17" from the get go I believe. You could, if you’re looking to replace the complete units, look at aftermarket (unless originality is your main thing) where one coilover fits across the range, irrespective of wheel size, model spec, soft top or hardtop making it much easier to select the correct fitmemt  only joking of course, are your coilovers yellow Bilstein units? If it is a sport, then again, they should be. 


Hi there, If you’ve got a 2.0 sport the wheels should be 17 inch and you should have a six speed gearbox. This model also has Bilstein (yellow) shock absorbers and the springs are specific to the 2.0 sport.

The other 2.0  model is known as the option pack and has 16 inch wheels, five speed gearbox and standard springs and shockers.

The 16 and 17  wheels are interchangeable and circumference is not a lot different.

hope this helps, Colin 

Post me your VIN number on a privte message.

Hi All,

Thanks for replies. Actually, it looks like I don’t have the Sport - it has a 5 speed gearbox and I think the shock absorbers are black - certainly not yellow. I’m not sure why I assumed it was; does this help things?

Thanks Eddie - I’ll post when I get home.




does it have the strut brace ? leather seats ??