Mad Russ Posted April 6, 2006 Report Share Posted April 6, 2006 When bigger alloy's are fitted should the tyre pressures be altered. I would have thought so but I've had varied oppinions on this. The Missis FTO has 18" alloys with 225/35/18 tyres IIRC which are huge compaired to the std 16" wheels and scrubbs both inner and outer edges on both front tyres which screems under pressure to me. So how do I work out what it shoud be as they have been set on the factory pressures AFAIK Quote Link to comment Share on other sites More sharing options...
Tony Posted April 6, 2006 Report Share Posted April 6, 2006 When bigger alloy's are fitted should the tyre pressures be altered. I would have thought so but I've had varied oppinions on this. The Missis FTO has 18" alloys with 225/35/18 tyres IIRC which are huge compaired to the std 16" wheels and scrubbs both inner and outer edges on both front tyres which screems under pressure to me. So how do I work out what it shoud be as they have been set on the factory pressures AFAIK Good question..... first remember tyre pressures displayed by the manufacturer should be viewed as suggestions... within reason! move away from stock then you become the judge and jury. In answer to your question, there is a need to understand first so i question you this.... All cars display different pressures according to speed and load, do you know why? Note: this method of reply is not an attempt to belittle you, it's designed to make you think! Quote Link to comment Share on other sites More sharing options...
discount tyres dan Posted April 7, 2006 Report Share Posted April 7, 2006 my answer would be its all trial and error, i have gone from 205/60x15 to 225/40x18 i kept the presures as standard 30psi front and 33psi rear, no problems so far. i would recomed a full geometry check-up as bigger tyres are usulay more expensive to replace Quote Link to comment Share on other sites More sharing options...
Mad Russ Posted April 9, 2006 Author Report Share Posted April 9, 2006 Good question..... first remember tyre pressures displayed by the manufacturer should be viewed as suggestions... within reason! move away from stock then you become the judge and jury. In answer to your question, there is a need to understand first so i question you this.... All cars display different pressures according to speed and load, do you know why? Note: this method of reply is not an attempt to belittle you, it's designed to make you think! Is it to do with the tempratures generated by the tyres and the weight there have to hold up? Quote Link to comment Share on other sites More sharing options...
Tony Posted April 9, 2006 Report Share Posted April 9, 2006 Good question..... first remember tyre pressures displayed by the manufacturer should be viewed as suggestions... within reason! move away from stock then you become the judge and jury. In answer to your question, there is a need to understand first so i question you this.... All cars display different pressures according to speed and load, do you know why? Note: this method of reply is not an attempt to belittle you, it's designed to make you think! Is it to do with the tempratures generated by the tyres and the weight there have to hold up? As i said to Dan... sorry to answer a question with a question but a direct reply without making anyone think is of little value.... 'i feel'. As a rule the wider tyre holds a higher pressure, this is an attempt to reduce the contact patch and keep the tyre cool, enivitably the tyre will become hot and then achieve the actual desired manufactured pressure, so the cold suggested (fictitious) 30psi would acquire the expected 36psi when warm. Then add speed and load to the possibilities then another set of figures are born...... If the journey involves the Motorway and additional load the the manufacturer suggests an even higher starting pressure, again this is an attempt to keep the tyre cool by reducing the contact patch.... eventually all the calculations suggest an equilibrium but this is not an exacting art. So what to make of all this?........... i recommend initially be guided by the manufacturer, moniteur the wear and apply your own pressure in reply to any adverse wear, within reason! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.