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Discussion Starter #1
Hi all,

Just need some advice re tyres. Im running the stock front of 225/40 R18 88W Bridgestone Potenza RFTs and rear of 255/35 R18 90W Potenza RFTs. i think the rear is the RE050A1.

So I had the TPMS warning today so checked my tyres. Two on the drivers side had essentially recommend pressure. But the two on the passenger side were way off.

The really surprising one was the rear which was 0.5 bar (7.25psi) recommend is 2.7 bar (39.1psi).

FWIW i had some similar troubles with the rear passenger tyre a couple times in the past where this one would lose air quicker than the others but never to this pressure. I think the last one was down to 2.3bar.

The front pass was 3.8 bar (55.1 psi) recommended is 2.6 bar (37.7psi). I had this alloy refurbished about 6 weeks ago and I have not found the driving to be odd. They also did the two drivers side alloys and pressure in them was fine today. I certainly didn't check the tyres after this. The work was done by a BMW body shop.

So I guess I have two questions
1) Is the rear one likely to be flat? Seems at that pressure there must be a leak? it has since become a bit colder here but surly not enough to cause such a drop. Maybe given the issues it is worth just getting it replaced.

2) Is it bad news that I have been driving on such a high pressure for the front passenger tyre?

Thanks for your help team!
 

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I would check your tyre valves for tightness, then monitor the pressures over 1-2 days depending on your journeys.
If the tyres are stil losing air & the treads have sufficient tread, then I would have them removed, tyres inspected for foreign bodies, new valves fitted, tyre rims cleaned and tyres reffited

On my experience with my local BMW dealer on a wheel refurb, they released the air from the tyre valve but left the tyre on the rim whilst it was refurbed, then re inflated the tyre, fortunately mine was fine, but it was a relatively new alloy.

older alloys can get rust on the inner rims so the tyres don't seal to the rim, tyre fitters normally wire brush the alloys before fitting new tyres so they seal correctly.

over inflation is not good over a long time as it quickens tyre wear, providing the tread is fine across the width then the tyre should be ok, but inflate to the recommended pressure.
 

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Discussion Starter #3
Thanks mate,

I think you helped me out when I first moaned about my tyre issue a year ago, you had cracked rubber right?

By valve tightness you mean the stem right not the valve cap? Sorry dumb question.

Should i putting some miles on the car to test this? Over the next 2-3 days ill prob only drive 20 miles max.

Btw the wheel which was the lowest pressure was not refurbished but was the one which has always lost air quickest. And no rubber cracks :p

Thanks!
 

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only 0.5 bar on one tyre?! would think you'd notice that when you drive it

ye valve could be the problem, was mine 2 weeks ago, had bought old rims, rims are fine but 2 of the valves not!

don't think you need to drive to test loss of tyre press., btw every time you measure the psi the tyre will loose some psi, nut not much

at tyre center they put the tyre in a water bath and where bubbles = leak

if it's losing at the valve you may see it yourself by spraying some liquid on the valve and check for bubbles
 

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checked your manual, was actually surprised E92s can have lower load index than E46s! E46 is on the heavy side ;)
BMW 3 Series Manuals Download - BMWSections

anyway, if you don't have sports package and no XL tyres i read yo should put on 2.2 and 2.4 pressures (or 2.5 and 2.6), just mentioning this cause you mentioned 2.6 and 2.7 and don't find that, for XL tyres they rec. 2.5 and 2.7, or maybe the manual is diff. than yours, you've got XL tyres?
 

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Discussion Starter #6
Hey all thanks for your input

only 0.5 bar on one tyre?! would think you'd notice that when you drive it
ye valve could be the problem, was mine 2 weeks ago, had bought old rims, rims are fine but 2 of the valves not!
think you need to drive to test loss of tyre press., btw every time you measure the psi the tyre will loose some psi, nut not much
at tyre center they put the tyre in a water bath and where bubbles = leak
if it's losing at the valve you may see it yourself by spraying some liquid on the valve and check for bubbles
You think I would have noticed right.. it was a very short drive and the TPMS only went off as I was pulling in to where I needed to be. I am about to head to the gas station to see what it is no 6 hours later.


checked your manual, was actually surprised E92s can have lower load index than E46s! E46 is on the heavy side ;)
BMW 3 Series Manuals Download - BMWSections

anyway, if you don't have sports package and no XL tyres i read yo should put on 2.2 and 2.4 pressures (or 2.5 and 2.6), just mentioning this cause you mentioned 2.6 and 2.7 and don't find that, for XL tyres they rec. 2.5 and 2.7, or maybe the manual is diff. than yours, you've got XL tyres?
Hey Indiana, I am just going off the plate on the drivers sill (See attached) My tyres are in the bottom left corner of the image. This is what I have used for the past couple of years. Is it right? IMG_1334.jpg

Cheers
 

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ye 2.6 and 2.7 indeed,

weird on manual i downloaded saw other values, maybe diff. manuals 4 diff. countries...

2.6 up front is quite a lot for non XL tyres and unloaded car

whatever they recommend, is good to experiment yourself what you prefer, i've been changing a lot lately!

4 staggered setup would def. put more in rear tyres compared to fronts to reduce understeer (and a square setup must be more RWD fun, esp. on a 335i!)

a pressure meter is only about 10 pound...
 

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RFT these are different to non run flat XL tyres.
you need to check the tyres for the exact markings and match them up to the door plate settings for your pressures.

yes I mean the valve stems check the tightness.

IF your tyres are loosing great amounts of air, then I would be looking at having the tyres removed for further investigation.
I had a similar thing with my daughters car, the tyre was removed, alloy inner rim cleaned, new valve fitted, tyre seating gel applied, tyre refitted balanced, perfect job, tyre was air tight, no further issues.
Good luck :thumbsup
 

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Discussion Starter #9
ye 2.6 and 2.7 indeed,

weird on manual i downloaded saw other values, maybe diff. manuals 4 diff. countries...

2.6 up front is quite a lot for non XL tyres and unloaded car

whatever they recommend, is good to experiment yourself what you prefer, i've been changing a lot lately!

4 staggered setup would def. put more in rear tyres compared to fronts to reduce understeer (and a square setup must be more RWD fun, esp. on a 335i!)

a pressure meter is only about 10 pound...

Can you explain what you mean about the setup??

Just check pressures, had to go to the service station.

So the tyres are cold now (when i filled up last time was afar about 6 miles on motorway) and it is also colder now. Overall all pressures were down. Fronts were 2.4 and 2.5 I had just filled them up to 2.7 bar.

But the culprit, rear passenger, was now down to 2.1 (filled it up to 2.7 bar) the other rear tyre was 2.5 (was 2.7)

So something fishy going on. Will take it to National Tyres today. They had the cheapest for a Bridgesotne Potenza RE050 RFT.

Cheers
 

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when my tyres are warm think they def. +0.1 bar

square setup = 4 identical tyres
staggered = wider at the rear

on the manual i downl. there r no square setups recommended 4 summer tyres (only 4 winter), well it is a powerful car of course,

with a square setup the 335i will feel more alive and more easily power oversteer and def. less understeery, maybe check out what other E9x drivers prefer or if i were you would give a square setup a try, but then again i like 2 experiment with diff. tyre sizes ;)

about RFT's, u know RFTs are more expensive, heavier, less grippy and less comfort.?
 

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Discussion Starter #11
Oh I see. I know RFTs are not ideal for those reasons but what do you do re spare? A flat like this and id need a tow right? there isn't any room in the boot!
 

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Oh I see. I know RFTs are not ideal for those reasons but what do you do re spare? A flat like this and id need a tow right? there isn't any room in the boot!
buy this
Slime 1800330 10914 Tyre Repair Set for Automobile Tyres with Dispensor: Amazon.co.uk: Car & Motorbike

works in many cases,

i've got it too instead of spare tyre + jack

an RFT isn't full proof either btw

on my other car i still got a spare, had flat tyre, still drove home, was closeby, but then couldn't unscrew the bolts! so was useless anyway

if you put on good comfy sports tyres like Mich. PS2 PS3 PSS (and there r many other) your 335 will drive much better
 

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Discussion Starter #13
yep so it was a puncture! Nail on the inside wall of the tyre. Got it replaced.

I found the cheapest fitted Potenza at tyreshopper.co.uk, was 10 quid cheaper than the other competition and could use paypal and thus Amex. They fit the tyre at the National Tyre chain.

Cheers for all the help!
 
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