255/30/19 - ‘upgrade’ to 255/35/19 (E89)

B

Braveatom

Member
 London
Has anyone changed the tyres on the rear of an E89 to a different profile?

The tyres need replacing this week (slow puncture isn’t so slow anymore!) and looking around, 255/35/19 are half the price of 255/30/19, and I assume the ride comfort may benefit. In real terms it means a change in diameter of 25mm, so 12.5mm extra height from the centre.

I’m concerned it’ll rub (biggest concern) , or give incorrect data about milage / speed.

Thanks!

Chris
 
Braveatom said:
Has anyone changed the tyres on the rear of an E89 to a different profile?

The tyres need replacing this week (slow puncture isn’t so slow anymore!) and looking around, 255/35/19 are half the price of 255/30/19, and I assume the ride comfort may benefit. In real terms it means a change in diameter of 25mm.

I’m concerned it’ll rub (biggest concern) , or give incorrect data about milage / speed.

Thanks!

Chris
Click to expand...

It’s been done quite a few times by other forum members here, the plus is improved comfort and less risk to some of the fragile 19” rims. The downside is a slight reduction in both acceleration and fuel efficiency.
 
I have 255/35/19 on the rear of my E89 (M-sport suspension). No rubbing problems whatsoever. There is at least 20mm arch gap. Remember you only lose half of the diameter increase in arch gap, as the car rides higher by the other half. :)

3% speedo difference so will probably make it more accurate as analogue speedos are notorious for being 'optimistic'.

The extra tyre wall should also help a little with comfort and help against wheel cracking.

Not had any DSC issues either. :thumbsup:
 
Not an E89 admittedly but I fitted 255/45 x 18 to the rear of my Z4M instead of the OE size of 255/40 x 18 with no issues - if anything it has made the speedo more accurate!

In your case the diameter of the tyre is only going up 5% of 255mm so that's only 12.75mm. Which means you only need another 6.375mm clearance in the wheel-arch.
 
Mr Tidy said:
In your case the diameter of the tyre is only going up 5% of 255mm so that's only 12.75mm. Which means you only need another 6.375mm clearance in the wheel-arch.
Click to expand...

That's the radius Iain. Diameter is double that, so 25.5mm.
 
Braveatom said:
Has anyone changed the tyres on the rear of an E89 to a different profile?

The tyres need replacing this week (slow puncture isn’t so slow anymore!) and looking around, 255/35/19 are half the price of 255/30/19, and I assume the ride comfort may benefit. In real terms it means a change in diameter of 25mm, so 12.5mm extra height from the centre.

I’m concerned it’ll rub (biggest concern) , or give incorrect data about milage / speed.

Thanks!

Chris
Click to expand...
I’ve been running 255/35/19 rears for a few years and definitely no rubbing. Can’t say I’ve noticed any change to the accuracy of the Speedo either but a big improvement in comfort (set at 36psi) over the runflats that the current tyres replaced.
 
Wow, thanks for all the great replies, it’s exactly the info I was after and then some.

Think I’ll do it - it appears to be a net benefit. Both my rear alloys are cracked and need sorting, so saving £250 on a pair of tyres is really gonna ease the pain.
 
I went up to 265/30/19 with no issues. The increase to the sidewall because of the slightly wider tyre gave a bit more protection to the rim
 
Z4Shane007homas said:
Which is the best website to purchase tyres online ?
Click to expand...

Unless you can get them fitted for free, I've not seen a saving on buying online TBH.

I just ring round my local tyre garages and get quotes for the tyres I want. One or other usually beats the online people.

When I lived in your area, I always used the tyre garage in Piddington (on the A40 past West Wycombe going towards Stokenchurch). Or Adams & Page on Cressex estate.
 
Im going to buy new tyres in the spring and will probably do 35 profile rears - it seems well documented that its ok - but should the fronts just remain at the standard 35 profile?

Currently looking at the Conti Contact 7's
 
ronk said:
Im going to buy new tyres in the spring and will probably do 35 profile rears - it seems well documented that its ok - but should the fronts just remain at the standard 35 profile?

Currently looking at the Conti Contact 7's
Click to expand...

Yes, 225/35/19 or 235/35/19 will work fine with 255/35/19 rears

My VO E89 had the 235/35/19 & 255/35/19 Combo, and I’m just about to fit 225/35/19 & 255/35/19 onto my DSB E89

The VO had 9J fronts and 10J rears - the DSB has 8J fronts and 9J rears.
 
Thanks.
Now the search begins.
I t think my choice is between Conti 7 snd Michelin ps4
The Conti do seem a lot cheaper- but some reports say they have a better feel.
 
Argyll Andy said:
I went up to 265/30/19 with no issues. The increase to the sidewall because of the slightly wider tyre gave a bit more protection to the rim
Click to expand...

This seems to be a better shout than 255/35.
 
warmasice said:
Argyll Andy said:
I went up to 265/30/19 with no issues. The increase to the sidewall because of the slightly wider tyre gave a bit more protection to the rim
Click to expand...

This seems to be a better shout than 255/35.
Click to expand...

Far more expensive though
 
On the E89 it’s folklore that you should try and keep the rolling diameters front and rear within 2%

It’s alleged that the DSC can get confused on this model when the differences are too great..
 
B21 said:
On the E89 it’s folklore that you should try and keep the rolling diameters front and rear within 2%

It’s alleged that the DSC can get confused on this model when the differences are too great..
Click to expand...
I would agree after all the research I did recently on different width/ profile tyres on a BMW. I should have shares in 'willtheyfit'. :)
 
so it is ok to raise the profile aspect 5% on the rears without changing the front without any detrimental effect ?
 
ronk said:
so it is ok to raise the profile aspect 5% on the rears without changing the front without any detrimental effect ?
Click to expand...

If you are saying 255/35/19 as opposed to 255/30/19, then yes. I have had that profile on mine (with standard 225/35/19 fronts) for at least two years without any issues whatsoever. Although they are 3% larger circumference than 30 profiles.

As Peter said there is folklore (and I have not seen any proof, anywhere, so it is folklore) that the DSC is programmed at the factory for a very small tolerance in changes in tyre circumference. The DSC isn't intelligent, so if you had a larger circumference wheel/ tyre it would just think you were travelling at a % percentage slower speed so the DSC would intervene less. That's my logical take on it, anyway, with no proof whatsoever! :)
 
Pondrew said:
ronk said:
so it is ok to raise the profile aspect 5% on the rears without changing the front without any detrimental effect ?
Click to expand...

If you are saying 255/35/19 as opposed to 255/30/19, then yes. I have had that profile on mine (with standard 225/35/19 fronts) for at least two years without any issues whatsoever. Although they are 3% larger circumference than 30 profiles.
Click to expand...

Yep, exactly this. I’ve literally just gone down this route again today :thumbsup:
 
You must log in or register to reply here.
Back
Top Bottom