Rx Tyre Pressures & Fuel

[RxMike]

Dear all

I just wanted to ask what tyre pressures you are all running on.

My RX 300 SEL was delivered last month and came fitted with Dunlop Sport 270 235/55 R18 99V rated tyres.

After a week of driving I checked the pressures for the first time and found the tyres were inflated to 55 psi! The owners manual states they should be 32 psi which is where I immediatley deflated them to, however, sometimes looking at the car whilst parked they look to be a little soft.

The ride is obviously alot better now they are at the correct pressure but has the dealer inflated them to this higher pressure because he knows something I don't or should they be kept at the recommended 32 psi.?

I feel the overinflation was a result of an errror on the part of the dealership but surely this is something they should have checked on the pre handover checks?

(Interstingly 55 psi equates to roughly 3.2 BAR on the tyrwe pressure gauge!)

FUEL

Also what type of unleaded do you use, regular or super.

The dealer advised me to use regular and that putting super unleaded in would simply waste money - HOWEVER - the owners manual advises to use fuel with a RON of 95 or higher. My understanding is that regular unleaded has a RON of between 89 and 95 whilst Super Unleaded has a RON of between 95 and 98, therefore meeting the owners manual requirement of using a fuel of RON 95 or higher! (RON - Research Octane Number).

The engine definatley seems more 'punchy' with the super unleaded in it and has not yet sufferd any pinking noises or the like.

IMHO it seems to be running far nicer using the Super than it did with the Regular.

I also only use Texaco fuel as I am of the understanding that the clean system 3 fuel which they sell is the only fuel on the market which actually lubricates the bore as it burns - unlike all the other fuel types which do not.

This is only really a 'food for thought' discussion but it will be interesting to see your various ideas.

RxMike

[ColinBarber]

unleaded is 95RON and super is 97 +

[JohnRX400h]

I'll drop in a tank of Optimax next time and see what happens, that is of course if I am able to take all my savings out of Caymen, Switzerland, and Jersey to pay for 65l of the stuff!

[IanHeathcock]

I have a 3 1/2 yr old Mk1 RX300, over the last few months I've switched to Optimax from SHELL - what a difference the car is quieter and I get better MPG, average 27mpg, before I was getting 25.

Ok, tis dearer but better alround performance and better shell reward points!! and the company pays the £150 a wk petrol bill!