Larger profile tyres

[ClumUK]

I need new tyres and want new wheels for my 2010 E89 35is.

I've currently got aftermarket 19" 343M style alloys which I love the look of, concave & gunmetal with machined face, however for several reasons I want them gone (diamond cut is impractical, they're too wide, they need a refurb, no rim protection, and tyres are expensive).
I'm running 235/35/19 fronts and 265/30/19 rears, I believe they are 8.5J ET38 / 9.5J ET40 but I have no idea if I'm using spacers as they were on the car when I bought it.



I'd like to stick with runflats as I don't want any hassle regarding insurance or european breakdown cover etc, and I'm thinking 18" to achieve a slightly better ride. I also want to get as close to the stock staggered spec as possible so 8Jx18 ET29 / 8.5Jx18 ET40 but I'm struggling to find any wheels that match this exactly.

I've got a budget of about £1k so ideally I'm looking for 2nd hand genuine BMW wheels from other models. Although some do look great I'm slightly against aftermarket wheels due to many of them needing slim bolts and not fitting BMW sized centre caps.

I'm finding a lot of good VFM packages on eBay and the like with refurbished wheels & premium part-worn RFT fitted (400M style for example), but they never seem to have the right offsets or tyre aspect ratio, it's always a slightly larger. So it's got me thinking if they'd actually be suitable for me or not...

Given the correct size would be:

Front: 8J ET29 - 225/40/18
Rear: 8.5J ET40 - 255/35/18

If I replaced with:

Front: 8J ET34 - 225/45/18
Rear: 8.5J ET47 - 255/40/18

• Would these offsets be ok without rubbing or would spacers be required?

• And would these tyres be ok to fit? I know the profile would make the speedo read off by about 3%, but would the thicker sidewalls also help with handling/ride?

I've stressed myself out trying to decide what to do so just needed to write it all out and get some thoughts!

 

[Mr Tidy]

I bought a set of staggered 18" Style 295s from a 35is for my previous Coupe.

They were 8Jx18 ET29 fronts with 225/40 tyres and 8.5Jx18 rears with 255/35 tyres so would fit your car just fine, and they were so easy to clean! But sadly they are NLA.




ET34 fronts may be OK but I think a spacer would probably be needed/desireable for ET47 rears.

 

[mr.tourette]

As mr.tidy mentions you will likely be fine on e85 tyre sizes, some of the new generation runflats ride pretty well by all accounts ..I believe the latest Pirelli runflats are almost indistinguishable from regular tyres so you should benefit a little..I'd be wary of slamming on any old part used runflats though if ride comfort is a priority and put your money into getting the right tyres on a possibly used set of wheels if you are on a tight budget

 

[mmm-five]

Just by going to the standard profile/offsets of the 18" you'd get more sidewall anyway...without risking any rubbing or speed inaccuracy (4.0% on the 40 profile rear option)...and would save you worrying about whether something else would fit or not.

However, I don't think 5mm extra on the offset would cause a concern with standard size tyres, you'd only have to be careful if you also put wider tyres on.

Don't forget that you'd also end up having a different circumference tyre on the front and back if you went up to a 40 profile on the rear (would be 1" bigger diameter than the front), as the standard sizes are within 0.2% of each other vs the 3.8% that the 40 profile rears would be.

Whether that matters or not on an e89 I could not say.

 

[sars]

No disagreement with what’s gone before, if you want a softer and quieter ride then 18’s are better than 19’s and run flats are worse than conventional.

One point that did confuse me, you’ve stated that you don’t want to ditch the run flats and go to conventional tyres because of the insurance notification, however you are happy to go away from manufacturers stated tyre sizing even though this could affect your insurance as it’s a modification……

 

[ClumUK]

No disagreement with what’s gone before, if you want a softer and quieter ride then 18’s are better than 19’s and run flats are worse than conventional.

One point that did confuse me, you’ve stated that you don’t want to ditch the run flats and go to conventional tyres because of the insurance notification, however you are happy to go away from manufacturers stated tyre sizing even though this could affect your insurance as it’s a modification……

I'm happy to inform my insurer of a modification regarding larger tyres, but afaik insurers do not like switching a car from RFT to standard, I guess as there's no spare tyre etc?

My main issue here is budget, which is why I was looking for wheel & tyre sets. Annoyingly it just seems that the majority of other BMW models don't have low profile tyres like the Z (I need 225/40/18 & 255/35/18 but pretty much every set I see for sale has 225/45/18 & 255/40/18 fitted).

I'm aware there are a few direct fit alloys like the 295 and 326 which have the correct offsets, however they I don't like the style of the former and the latter would eat up my entire budget for a 2nd hand set before I'd bought any tyres.

If I were to buy brand new 18" RFTs of the correct size, I reckon I could get a full set of Goodyear Eagle F1s for about £550. That would only leave me £450 to buy the alloys and even 2nd hand that's cutting it fine

If my current set didn't need a refurb I'm getting to the point where I would just put new 19" RTFs and be done with it, but I'm not forking out £575 to have them refaced just so my wife can curb them again!

 

[mmm-five]

The cars that used 225/40r18 & 255/35r18 were:

• e46 3-series, offsets et47 (f) and et50 (r)
• e9x 3-series - offsets et34 (f) x et37 (r)

So I'd say you've got a fair few options if the offsets work.

F3x 3-series uses 225/45r18 and 255/40r18 tyres on et34 / et47 offsets so that would match with the other wheels/tyres your finding

 

[ClumUK]

The cars that used 225/40r18 & 255/35r18 were:

• e46 3-series, offsets et47 (f) and et50 (r)
• e9x 3-series - offsets et34 (f) x et37 (r)

So I'd say you've got a fair few options if the offsets work.

F3x 3-series uses 225/45r18 and 255/40r18 tyres on et34 / et47 offsets so that would match with the other wheels/tyres your finding

Thanks for the info, I'll have a look what I can find

It's my first BMW so I'm not au fait with compatability between other models.