| Index
to articles on replacement tyres available on the V8 website Updated: 150113 Posted: 131025 | Members'
views on replacement tyres Finding good comparative tyre test information Choosing replacement tyres has been made easier by the compulsory performance labelling but if you want comparative performance information on the top tyres then you need to see the results of recent tyre tests. Here we have looked at two independent comparative tyre tests carried out in by AutoExpress magazine in September 2014 and earlier by the independent consumer organisation, Which? 150113 More Replacement tyre survey - MGV8 members views An ongoing survey records members' views and choices of replacment tyres for their MGBGTV8 and RV8 models. Survey report Comments on replacement tyres from MGV8 enthusiasts Feedback and V8BB comments on replacement tyre choices. More Replacement tyres - members' comments in V8BB postings Replacement tyres are a regular topic on the V8BB. Here are some of the archived postings. V8BB1 & V8BB2 & V8BB3 & V8BB4 RV8NOTE160 - Replacement tyres for an RV8 As most RV8s seem to be low mileage vehicles, the topic of replacement tyres had not been covered in the RV8 Workshop Notes series in 2002, so a request for members' views on tyres was sent out by email and a message posted on the V8 website Bulletin Board. This note is a summary of the feedback received from our RV8 members. 011102 RV8NOTE160 Understanding tyre sidewall markings Tyre sidewall markings Understanding the markings on the sidewalls of tyres will help you to choose the right tyres for your car. Here's a guide to those sidewall markings using a 175/80 R14 88H tyre as an example. 290608 More Aspect ratio, rolling circumference and gearing The aspect ratio of a tyre is the ratio of the "section height" of the tyre to the "section width", expressed as a percentage - see the sketch in V8NOTE187. Traditionally radial ply tyres have nearly always had an aspect ratio of 82% and because this was so universal, it was never marked on the tyre. Thus for example the correct tyre for the MGBGTV8 is a 175/82 although the 82 is rarely referred to. Nowadays of course we see a proliferation of different "low profile" tyres with aspect ratios of 70, 65, 60 and even lower. A 185 tyre for a 14 inch wheel will typically have an aspect ratio of 70. So the section height on a 185/70 tyre is lower than that on a 175/80 and consequently the rolling circumference is lower too. For the 185/70 it is 2019mm and 175/80 1931mm or 4.36% less which of course affects the gearing of the car. V8NOTE187 - Tyre aspect ratio A useful insight to tyre aspect ratios. 010591 V8NOTE187 Contact patch size The tyre's contact patch is the only connection between the road and the vehicle. The size and shape of the contact patch, as well as the pressure distribution over the contact patch, are important to the ride qualities and handling characteristics of a vehicle. Since the wear and performance characteristics of individual makes of tyre are sensitive matters for tyre manufacturers and a source of competition between them, very little is published on the subject other than marketing claims to promote individual tyre products. As pneumatic tyres are flexible, the contact patch is different when the vehicle is in motion and when it is at rest. As observations of the contact patch can be made so much more easily when the tyre is stationary, it is more common to conduct studies of the static contact patch. Then the size, shape and pressure distribution of the contact patch are determined by a number of factors, the most important being the load on the tyre and the tyre inflation pressure. The greater the load on the tyre then the larger the contact patch. The larger the inflation pressure, the smaller the contact patch. Unfortunately, changes in these factors are not linearly proportional to the area of the contact patch because whilst either of those factors can be varied by additional loadings or increases of pressure, the resulting impact on the area of the contact patch is constrained by the structure and geometry of the tyre. Tyre pressures for an MGBGTV8 and RV8 What tyre pressures are suggested today for an MGV8? Although much has been written about tyres on the V8BB, I haven't seen anything about tyre pressures used by other members. In this note Ron Gammons sets out his personal views on tyre pressures for the MGBGTV8 and RV8. 301210 More Winter tyres and snow tyres Are winter tyres worth the expense? Winter tyres are not snow tyres. One of the most common reasons we hear winter tyres aren't needed in the UK is because we don't get enough snow. Winter tyres are designed to be more effective than regular tyres in any temperature under 7C (44F) on any type of road. Cold weather tyres are designed with a larger percentage of natural rubber and silica in the compound which doesn't harden up as much as synthetic rubber in cold conditions. 051210 More |
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