20" staggered setup tyre pressures
 

Hi guys, new registered forum member here!

I was wondering what the best pressures are recommended for the E70 with the M-Sport package, running staggered 20" wheels with 275/40/R20 on the front and 315/35/R20 on the back? We have been getting a lot of inner tyre wear and it is becoming costly.

Thanks in advance

WHAT ARE YOUR SPECIFIC ALIGNMENT NUMBERS????????????????

way, way more germane than tire pressures.


What brand/model tire? What pressures are you currently running?

Haven't got any alignment numbers, local tyre shop near to me (large chain supplier) do Hunter alignment on the car for me but I haven't asked for alignment figures (silly me). They do it every few months, competitively priced too.

Run Bridgestone Dueler H/P Sport RFT XL Star Marked (BMW) 106 W and 110 W front and back respectively. Have been running 40PSI on front and rear.

20" staggered setup tyre pressures
 

I’m with ard - sounds more like a potential camber issue more than a tire pressure issue.

I would take it back over and show them the excessive wear, ask them to check the alignment and provide you with a full, four wheel report.

If they aligned it last and can’t help you with verifying the specs... tires are pricey, I’d find another shop.

Read this thread:


https://www.bimmerfest.com/forums/sh...d.php?t=668729


Ive posted a ton on alignments, but this thread is a good summary.


A couple of takeaways:
1. Every car, every mfg, every model- the alignment 'specs' define a RANGE of values. Do not assume it is a binary thing- 'aligned' or 'not aligned'


2. Within these specs there are 'better' alignments.


3. BMW dealers and many tire shops are, in fact, pretty clueless.


4. Yoiu are 'allowed' to ask for specific numbers within the recommended range




Having said that....


BMWs have some camber in the rear, which improves handling ...HOWEVER... do not assume that is THE reason for inner edge wear. Here is the key: **TOE** on any wheel will accelerate the expected wear. SO while you can see the camber and think "oh thats why the edge wears", in fact you will likely see way too much toe on that wheel, combined with the camber.


Good news is by dialing back the toe, you can keep the camber for good handling, and get a ton of tire life.


As you will see in the thread- my recommendatiosn are simple:


0.01 to 0.02" toe in, each tire
Camber and caster mid spec, balanced from side to side (ie each axle)

In regards to tire pressure...the "best" is relative and subjective.

I would suggest to start with BMW's recommend inflation specs found on the driver's door/door jamb and the owners manual. Then adjust accordingly based on what you like if it's too soft, or too stiff/hard...or you don't like the tire wear if your alignment is all squared away.

You wrote that you run 40 psi front/rear...what made you choose that over BMW's recommendation? A quick Google search for an inflation chart from the e70 owners manual shows 32psi (front) & 35 psi (rear)...but double check the label on your driver's door or your owners manual selecting the chart that applies to what you have:

https://xoutpost.com/attachments/x5-...9-20-38-pm.png

Thanks for the replies everyone, very helpful advice given.

Generally run 40PSI on all the cars we own as they all have rather big profiles, so just got used to it. Not the best way to approach, but from now on I think we will follow the manufacturers recommendations for tyre pressures. We do carry 4 people quite a bit, so it would make good sense to use the proper pressures.

Also need to say this. Nearside front and Nearside rear tyres need to be changed because of there being cuts in the tyres (from rubbish UK roads). The rears have lots of tread left in them so not worried about changing those in pairs, but front tyres haven't got too much tread left. Do I need to be changing both of the fronts or not?

You said you often haul 4 people so I think the question is opinion based - if YOU think the tires are safe, then roll with them, if there not safe, change them [emoji106]

That said, if I had a tires that were “cut” and worn, those tires would be replaced - you also say that the fronts “haven’t got too much tread” so I think you’ve answered your own question - probably time for the fronts to be replaced.

Not sure that makes sense....

If worn under 50% you should not run that w a 100% on the other side.

Post your pre-alignment numbers up when you get them.