Tyres dilemma! New tyre urgently required, but how many/type/etc....

[jimmy_1981]

Hi,
I am new to this forum and also more importantly new to owning an X5 (or any kind of SUV), as the title suggests I need a bit of tyre advice. I have searched and read as many of the previous conversations but not answering my specific issues so thought I'd just ask (i'm prepared to be shot down on this).

I recently purchased a 2007 X5(E70) SE 3.0D (absolutely love the car!). The tyre tread looked ok when purchasing so was hoping to have a bit more time before looking at this.

A bulge has appeared on the sidewall of one of the rear tyres so I'm looking for a replacement asap and have many questions. Not sure how this happens but the garage we purchased the car from has kindly offered to replace it, but I want to make sure I get this right. Tyres currently fitted are 20 in:
- Front: 275/40 R20 kuhmo
- Rear: 315/35 R20 - Toyo Proxes

Not the best brands but not the worse, mixed but same axle so assume ok. Neither appear to be runflat or reinforced (although not sure about the reinforced part).

So can anyone advise on the following please?
-If I replace one rear, should i replace both?
-What i replace what is the minimum spec i should look for? Do i need to ensure they are reinforced or is this assumed for these vehicles? Spoke to a tyre garage who said load rating of 110, but blackcircles only has 106, so not sure if this is ok or not.

-Now, if i go crazy and go down the run flat route and replace all, what are peoples general thoughts?
-My wife will be driving this mostly so I want her to be safe, are they any better or worse?
-Does anyone know if run flats were originally fitted as standard?
-What are the downside with runflats on a vehicle like this? Assume noisy and bumpier, i would never fit them to a normal car but is it wrong to assume the difference is more negligible with an SUV?

Any help will be much appreciated, thanks!

[Alan Gunn]

I hate run flats very hard and on a 20" solid i would think but that's my opinion.
With the x5 you need to have the same tread depth on all 4 tyres or it can and will cause diff windup (look that one up) a very expensive repair.

[jimmy_1981]

Thanks for reply Alan. I'm not a fan of run flats and would never consider it for a car but i just feel slightly nervous with this type of beast. But good point, low profile run flats would be a solid lump.
I'll search that in a bit, does not sound like something i want to mess with, would hope that there is some tolerance as i would have thought tyres generally wear at different rates front/rear.
Also, i do not have a spare tyre? Just a bottle of gunk. Is this standard practice for X5's?

[Alan Gunn]

My x is the e53 that came with 19" normal tyres and a spare wheel.
Do have a good read up on the diff windup problem.

[Leslie]

HI Jimmy as I under stand it a tread depth difference of more than 3mm across any of the 4 tyres will cause problems with all modern 4x4 vehicles ,its not just a Bmw problem.
New tyres have 8mm so if any are at or below 5mm and you put a new one on you may well have issues , I had to fit a single tyre due to sidewall cord showing when i got it but my others were all near new like the one I took off so my difference was only 1mm.
They came with runflats but these are much more expensive ,often noisier and make for a hard ride so are often swapped to normal tyres . You can buy a space saver spare wheel and jack kit from Bmw but its about £230 so hardly a bargain but it fits in the underboot floor area of a 5 seater ,there is nowhere for it on a 7 seater. I currently do not have a spare wheel or runflats but I do have a compressor and a jack of an e53 .
The other problem with runflats is if you drive then more than a few miles or too fast when flat they are generally scrap after ...
The 110 tyre load rating is only for the 7 seater and doesn't apply to the 5 seater .

[NehalX5]

Star marked runflats (literally have a 5-pointed start next to the name on the tyres) were standard issue for these. Best bet with a staggered 20" setup on the X5 is to only have star marked RFT, as they ensure there isn't any issue with transfer boxes on these cars, of which can start to play up when the wrong type of tyres are used. They need to have the same wear pattern all around, something to do with rotational diameter, not too sure. Previous owner of our X5 complained of lots of grumbling from the gearbox/AWD system, so I would steer away and stick to what they ask for, as these cars are simply too complicated.

We run Bridgestone Dueler H/P sports on our X5 all around, they are XL load rated and either W or Y speed rating. They suit the car well, around town on rough roads the car gets quite jiggly but once on the move they work really well. They are amazing on the motorway, cannot feel road surface change, only hear it, and bumps are soaked up well on the motorway. Works really well with air suspension, really nice floaty feel when driving along, love it! Going at serious speeds (on private roads) and the car deals with it like nothing, rides like it is on rails. Astonishingly expensive but can be reasonable if you look around and do your research. We went lazy and spent too much for rears alone on these. Rears wore wrong because of tracking, which is really important to keep in check, but the fronts have lasted nearly three years and 35k miles which is absolutely amazing, considering how hard this thing gets driven at times, all whilst fully loaded. Kwik-fit do reasonable tracking at £90 and you can keep on getting it done every few months for 2 years. It is hunter alignment (what X5s need), and the rough roads really do disrupt the tracking on these, which can result in uneven tyre wear which you don't want.

[jimmy_1981]

Thanks for your advice guys...looks like this will be a very useful forum.
I have a lot of thinking to do, read up on the diff wind-up and really surprised by how delicate these vehicles are, point taken and will make sure get a good solution. Now it's the old question of how much money to throw at it

[snrbrtsn]

I should have a pair of 20” Pirelli RFTs, (new) coming up for sale soon if your interested
Purchased, never fitted