"I just had a great time understeering around that track in the wet" - said no one ever.
This guy is loving life.
Although both understeer and oversteer are undesirable if your objective is to drive as quickly as possible, at least one of them can provide hours of fun and entertainment (hint: it's not understeer).
In this article we will briefly discuss what understeer is and then cover some of the modifications which can be made to your car's suspension to reduce understeer.
What is understeer?
Understeer occurs when the front wheels lose traction whilst cornering whilst the rear wheels still have traction, causing the car to take a wider route than intended around the corner. This is often experienced by every day motorists as heading towards a hedge on the outside of a corner you do not want to head towards.
Most cases of understeer are caused by one or more of the following:
Applying too much throttle too early in the corner
Braking whilst entering the corner
Simply taking the corner too fast
Road conditions reducing traction e.g. ice/oil/diesel/mud/water
Clearly by the laws of physics you can not eliminate the above causes through modifications to the car, however there are many suspension adjustments which can be made to alter the understeer/oversteer behaviours of a car during different stages of a corner: corner entry, mid corner and corner exit.
How to reduce understeer
Reducing understeer by adjusting spring rate
Increase rear spring rate - this will increase the rear roll resistance which will reduce understeer but increase oversteer.
Decrease front spring rate - this will decrease the front roll resistance which will reduce understeer but increase oversteer.
Reducing understeer by adjusting the anti-roll bar (ARB)
Decrease front anti-roll bar stiffness - decreasing roll resistance at the front which will reduce understeer but increase oversteer. However, too much body roll could reduce tire contact patch size, increasing understeer.
Increase rear anti-roll bar stiffness - increasing roll resistance at the rear which will increase oversteer but reduce understeer. This may also reduce wheel camber change on cars with independent rear suspension, maintaining a larger contact patch whilst cornering and reducing oversteer.
As you can see, almost every change made to a vehicle's suspension will have more than one consequence so getting the balance right between understeer/oversteer/ride compliance/tyre wear/ and a million other variables requires expert knowledge and years of experience.
For the best results to suit your requirements, we would always recommend consulting a professional before putting your hand in your pocket to buy new parts.
The tyres (or tires for our American readers) are the most important factor on any car or bike for the simple reason that every change of direction is at the mercy of the grip provided by them. Four small patches which probably total up to be not much more than the size of an A4 piece of paper (on the 195/55/15 tyres used on many 306's) are all that is keeping over a tonne of car moving in the direction you want it to.
Steering left, steering right, braking and accelerating - all of these forces are acting upon the tyres and fighting for grip, adding to the load placed on them and when the total demand for grip exceeds the maximum grip a tyre can provide - traction is lost.
As with many areas of car maintenance there is a lot of myths and hearsay to watch out for, hopefully this guide will help you to make an informed decision and get the best Peugeot 306 tyres for your needs.
Contents
Tyre basics
Which type and size of tyres do you need
Where to buy
Tyre Basics
Before we start just a really quick overview of how a tyre is constructed and what the different markings and ratings stand for.
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A - 205 - Width of the tyre in mm's. A small supermini from the 90's might have a 155 width tyres but a BMW M3 might have 265.
B - 55 - Height of the tyre sidewall as a percent of width (A). 'Low profile' tyres as they are known have a low number here, they look very thin around the rim.
C - 16 - The diameter of the tyres inner rim in inches.
D - W - This is the speed rating of the tyre which determines the maximum sustained speed a tyre is designed to handle. Speed ratings are always give as a alphabetic letter, to see how this letter relates to a mph/kph figure check out this article on Black Circles.
A tyre is a flexible container which holds compressed air (usually about 34psi on standard family cars). Modern car tyres are made from many different components including:
the inner liner which holds the air
the bead which holds the tyres onto the rim and forms an air tight seal
steel belts which give the tyre shape and hold the tread flat for maximum contact
tread comes in many different patterns and compounds to suit a particular use
The tyre size on Peugeot 306's varies depending on the type of wheel fitted and range from 175/70/13 for the 1.4 to 195/55/15 for the sports models including GTi-6 and HDi DTurbo.
It is vital to check the existing size of tyre and make sure you order the same size. Do not assume the current tyres are the same size as what everyone else on the internet has as it is quite possible that a previous owner could have swapped to a different size.
If you are changing all four tyres then it is possible to change tyre size. For example, some people have switched from the standard 195/55/15 tyres to 195/50/15 because they are sometimes cheaper. The cost of doing this is reduced fuel economy, reduced comfort and the speedometer will be slightly more inaccurate due to the different rolling radius of the wheels.
Different types of tyres explained
Just a brief explanation to give you an idea of the different Peugeot 306 tyres available.
Winter tyres
Designed to offer high levels of grip on wet, mud, snow and ice. Normally the compound is also designed to work better at lower temperatures as well. A more thorough guide on winter tyres can be found on Honest John.
Summer/Performance tyres
Designed with maximum grip and performance in mind on dry roads. Summer tyres will generally wear out quicker due to the softer compound and will not give as much grip in wet conditions due to the tread pattern.
Track tyres
Drivers looking for the highest levels of grip will sometimes fit road legal track tyres. These will normally perform poorly in wet conditions and are prone to aqua-planing but the level of grip in the dry is exceptional. Examples of this would be the Toyo R888, Toyo R1r or Hankook RS2. Demon Tweeks frequently have excellent deals on a wide range of track day and high performance tyres.
Eco tyres
Designed to make your car more fuel efficient without compromising on wet or dry grip performance, eco tyres have added silica into the tread which reduces the rolling resistance of the tyre.
Run flat tyres
Run flat tyres can continue to be used to get home even when a tyre is punctured and has little or no air pressure. They have reinforced sidewalls and clips but should only be used with vehicles equipped with tyre pressure monitoring systems (e.g. not Peugeot 306's).
Which Peugeot 306 tyre to choose?
Since there are approximately five zillion brands and 'models' of tyre this can be a tricky decision to make. Just remember you are basically trying to find a balance between the following factors:
Grip
Comfort
Wear rate
Price
Generally it's going to be very hard to satisfy all of these requirements. Regardless of what your requirements are try and go for the most expensive tyres you can realistically afford. As we explained at the start of the article they are the most important safety feature of your car and as 'Fifth Gear' have shown in the video below, the stopping distance between budget and premium tyres can be quite substantial.
If you drive enthusiastically the difference between budget tyres and something decent will be immediately noticeable, for the every day driver maybe less so but the point is that in emergency situations when it really counts it could make the difference between a close call and an accident.
If you have been given a quote for a particular tyre check out TyreReviews.co.uk which is pretty much exactly what you would expect it to be - a collection of thousands of user-submitted reviews for almost every tyre you could come across. As always take these with a pinch of salt but they are great for getting a general feel of how a tyre performs in the real world under different driving conditions.
It really comes down to the type of driving you do and what the road conditions are like in that area of the country. If you have a Peugeot 306 Rallye for the weekends then a summer/performance tyre may do best, if you have a diesel workhorse in the Highlands of Scotland then an all-rounder/winter tyre will probably offer the best levels of overall safety.
A popular choice for drivers who require a high performance summer tyre is the Michelin Pilot Exalto 2 in 195/55/15 sizing. From experience they offer exceptional levels of wet and dry grip and also perform very well on greasy roads. Wear rate also appear to be very good, i've had a set on the front of my GTI-6 for approximately 5,000 miles of mixed driving now and they are doing very well. One negative point about these tyres which comes up quite regularly on the forums is the soft sidewalls which can give them a slightly unresponsive feel especially at slow speeds. I think they can sometimes give the appearance that they are not gripping when it is in fact just the tyre moving about before it starts to grip. Because of this the PE2's can take a little while to feel confident pushing hard but when you do the grip they deliver will just carry on coming - and the soft sidewall makes for a very progressive feel with no nasty snap when the limit of grip is reached.
Where to buy?
Tyre prices can vary substantially so the number one piece of advice is to shop around. There's basically three options to go for:
Buy the tyre(s) online and have them fitted locally.
Buy the tyre(s) and fitting online in one package and have them fitted locally at an affiliated tyre fitters.
Let your local garage handle everything.
I don't think there's any one option which is always cheaper as it depends on your tyre requirements. Obviously if you're buying the car tyres online without fitting you should first ring a few garages to get an idea of how much this will cost you - make sure you get a full quote including balancing and disposal of the old tyres.
There are many online tyre sellers such as Black Circles, CamSkill, MyTyres, Tyre & Auto Centre Group, eTyres and even Tesco. Once you have decided on the tyre you want, it is possible get a quote in seconds and even organise which local garage to get the tyres fitted at.
Don't automatically assume your local tyre place will be the most expensive either, they might have a special deal on or maybe business is a bit quiet. Get your best price and give them a ring and see if they can beat it.
Tracking and suspension check
If you haven't had the suspension or tracking checked recently it's a good idea to get the garage to check this out whilst they are fitting the new tyres. Obvious signs that something is wrong would be uneven tyre wear i.e. much more wear on the outer or inner edges. If there is something wrong then get it rectified, incorrect tracking could massively increase tyre wear and also will adversely affect the handling. Much cheaper to get it fixed sooner rather than wait for your brand new tyres to scrub out in 5,000 miles time.
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