Your tires are, next to your shock absorbers, one of the most important safety features of your Donkervoort. We frequently receive various questions on tires. Exposure to heat and the sun’s ultraviolet rays may cause structural changes to your tires. Although your tires may seem OK from the outside, the main issue on high performance cars such as the Donkervoort is deterioration of the inner structure of the tire. How old are your tires? Regardless of tread wear, vehicle and tire manufacturers generally recommend you replace your tires at six years. Donkervoort has used Toyo as the number one tire supplier at least going back to 1999. Below you will find an overview which Toyo tires have been mounted over the years.

Tires aging

Rubber compounds used in tires contain anti-oxidising chemicals that help to slow down the natural ageing process of untreated rubber. However, tires do deteriorate with age, which increases the risk of tire failure, and there are many ways in which this can be spotted:

• Cracking/crazing on the side wall of the tire, caused by its flexing
• Distortion of tire tread
• Deformation of the carcass of the tire

Tyre flexing. You don’t want this with older tires when the carcass is cracked, the tire will potentially pop off the rim hump!

There will also be a deterioration of the ride quality caused by vibrations through the tire. This may signify the tire’s performance has been affected by age and should be investigated as soon as possible. All tires that display signs of aging should be removed and not put to further use. Tires that have been in storage should not be placed into use if they are over 6 years old, from their date of manufacture.

Alway check the DOT code. Even if you have new tires fitted. DOT signifies that the tire complies with the United States Department of Transportation tire safety standards, and is approved for highway use.

In this case this Toyo tire is manufactured in week 13 of 2009.
If the DOT-code date on your Donkervoort goes back longer than 6 years; replace your tires!

Measuring correct tire pressure

Maintaining proper tire inflation is relatively simple and essential to the overall tire performance of your Donkervoort. A properly inflated tire will provide longer life, quicker steering response, and a smoother ride than an improperly inflated tire. Both underinflation and overinflation can cause headaches like premature treadwear and possible tire failure. The best way to ensure you’re getting the most out of your tires is to check your tire pressure before each ride. Your tire pressure measured cold should be 1,2 Bar. Note: Especially important for proper rear end grip and safety.

Invest in a proper digital tire pressure gauche. A digital tire pressure gauge will provide accurate readings, but don’t forget that it operates on a battery. It’s best to use your personal tire gauge versus those available attached to air hoses at service stations. Getting you to the gas station will already heat up your tires, causing an incorrect measurement. Of all the pressure gauges out there, they’re the most likely to be weathered, and possibly inaccurate.

Storage tire pressure

Due to the fact that the weight of the Donkervoort is limited, the operation pressure is relatively low. This means that wen your tires are on driving temperature, and the vehicle is stored, you will fairly quickly have tires that are not round anymore. You feels this intens in your steering wheel when driving the next time you take the car out for a spin. If you store your car with inflated tires on 3,0 Bar, you wil not have that problem. Don’t forget to reduce tire pressure to 1,2 Bar before your next drive. And if you have the space in your garage, try to move your Donkervoort back and forth every week to prevent flat spots on the tire. You can also jack up your car and turn the wheels by hand.

Tire overview OEM supplied tires over the years

Toyo T1-S – discontinued
	If you still have these mounted on your Donkervoort today, purchase a new set of tires. They are dangerously old! You do not even have to  check the DOT code for this.
Models	All
Mounted	1999 – 2004
Front size	205/50/R15
Rear size	225/50/R15
Tire pressure	1,2 Bar

Toyo R888 semi slick tire – discontinued
	The R888 is an R-rated radial tire, but with a number of key changes compared to the T1-R and T1-S road tires. These are: Use of a medium race rubber compound, increasing dry grip and expense increased wear and reduced cold weather performance. Fewer, but larger rain channels, exposing a much larger percentage of rubber to the road than found in a normal road tyre. Significantly strengthened and reinforced tyre casing compared with normal road tires. In truth the R888 is an acquired taste. You will either love them or hate them. Let’s make no bones about it. The R888 is a racing tyre made road legal. As such the tyre is made from a significantly softer compound than anything you will get on a normal road tyre. Whilst this means that when in the dry and at the correct operating temperature the tyre’s dynamic envelope is extrordinary, it also mean that the tyre will wear approximately twice as fast as a road tyre. The soft rubber is also prone to punctures and cuts, and small stones will be picked up and hurled at the car behind you. Grip in the wet is actually a lot better than you would initially think. To my personal experience -and the experience of Denis Donkervoort- a LOT better than the T1-R and any other tire. Especially on the GTO with it’s loads of mechanical grip and stability. Year round. In fact the tyre exceeds the grip of a normal road tyre in wet/damp road conditions due to the sheer amount of rubber contacting the road. However all this changes as soon as water begins to sit on top of the road surface; with a large rubber area and comparatively few water channels, the R888 is a tyre you have to treat with great respect when standing water abounds. Indeed even maintaining a steady motorway 100 – 120 Km/h in “medium” rain is a matter of bravery. Aquaplaning is an almost common occurance – you only need to hit a puddle at 90 Km/h and you’re there. Again this is something I have just learned to adapt my driving style to, but some people might find it very constraining or risky.
Models	All
Mounted	2000 – 2016
Front size	D8: 205/50/R15 – D8GT: 215/45/R17 – D8 GTO: 215/45/R17
Rear size	D8: 225/50/R15 – D8GT: 235/45/R17 – D8 GTO: 245/40/R18
Tire pressure	1,2 Bar

Toyo T1-R
	Perceived by Denis Donkervoort to be a rather tricky rear-end-grip tire in the wet on D8 models 180 BHP or higher.
Models	All
Mounted	2004 and onwards
Front size	205/50/R15
Rear size	225/50/R15
Tire pressure	1,2 Bar

Toyo R1-R
	Introduced initially on the D8GT.
Models	D8 GT and D8 GTO
Mounted	2013 and onwards
Front size	D8GT: 215/45/R17 – D8 GTO: 215/45/R17
Rear size	D8GT: 235/45/R17 – D8 GTO: 245/40/R18
Tire pressure	1,2 Bar

Toyo R888-R
	Replacement of the popular R888. Currently used on the D8 GTO and GTO-RS as a result of production and delivery problems with the preferred Hankook Z221.
Models	All
Mounted	10/ 2016 and onwards
Front size	D8: 205/50/R15 – D8 GTO, D8 GTO-RS: 215/45/R17
Rear size	D8: 225/50/R15 – D8 GTO, D8 GTO-RS: 245/40/R18
Tire pressure	1,2 Bar

Hankook Z221
	This tire was used by Donkervoort from early 2015 and onwards as a replacement for the R888 which gave problems in the supply before the market introduction of the Toyo R888 replacement, the R888R.
Models	D8 GTO
Mounted	2016 and onwards
Front size	D8 GTO: 215/45/R17
Rear size	D8 GTO: 245/40/R18
Tire pressure	1,2 Bar