Anyone tried 255 35 tyres on 18 x 8.5 or 9j wheels?

[muckipup]

This is a bit of a thread resurrection from 2012 ( http://www.briskoda.net/forums/topic/226132-anyone-running-255-35-tyres-on-18-rims/ ). I have changed car but still have this on my mind and would have given it a shot by now if it wasn't for all the unknowns.

What I do know is that it will be a close call!

Talk in the previous thread where someone had managed this on a Mk5 GTI was that the Octavia may have a tad more room under the arches but I don't think so. At least I am only slightly below stock VRS ride height.

I would need new 8.5 or 9j wheels with an ET of about 50 and a spoke design to clear the Porsche calipers which narrows it down a lot. The best option seems to be Team Dynamics Pro Race 1.3 which are 8.5j and the ET52 option....better to sling on 2mm spacers to clear the strut that have too much offset.

I may end up having a pop at this in the knowledge/expectation that I am probably committing myself to arch rolling, perhaps some slight arch pulling and possibly getting a degree or two of camber. It is a mental idea but I have a very open mind to anything that will help put a bit more power down after spending all that money to get it!

Just asking to try and get some insight where another Octy owner has done this before I get the wallet out (again!).

[muckipup]

I will take that as a 'no' then

[Brimma]

The highest I've ever heard of is 235 being used, I've no recollection of anyone using 255s so it's maybe not surprising you've not had much of a response

[muckipup]

Thanks Brimma. In fairness, I wasn't expecting much of a response to such a daft plan on my part. Jonnyc over on Mk5 has done this but had to roll and pull arches, trim bumper support brackets and dial in some camber! However, I don't know how lowered he was compared to mine, how his suspension struts measure up or what (if any) more room I have to play with under the Octavia's arches compared to a a Mk5.

[Brimma]

There was once a guy who ran a certain size wheel and tyre on a Passat and swore blind that the Passat was the same layout as the Octavia

 

We all told him they wouldn't fit, he bought them, and guess what.........they didn't fit, and he he advertised them again straight away

 

There's only so many ways you can tell some people before you give up trying  

[muckipup]

I may be about to learn 'the hard way' too!!!!

[Brimma]

I may be about to learn 'the hard way' too!!!!

 

 

Either that or you'll have arches wider than a rally car  

[muckipup]

Already identified a local arch roller and adjustable camber plates!

Well, I have started the ball rolling and ordered some TD Pro Race 1.3 wheels at 8.5J with an ET52 offset. This will probably touch the struts but better to have the option of adding a 2mm spacer or whatever than the lower available ET of 45 and be committed to rally arches and the life of a 46 year old scene queen

I need new wheels whatever happens so I can buy a single 255x35 tyre and test things and if it is a nightmare simply fit 235x40 all round and only be out of pocket for any loss on the tyre.

[Anddenton]

Tbh you'll probably get away with it on the back but I think you'll definitely rub on full lock on the front.

[muckipup]

Pro Race 1.3 on way but is a custom order with 8.5J ET52 but will be 4-6 weeks before I see them from Team Dynamics.

 

I have bottled out of the 255/35/R18 tyres as it seemed too much like hard work after having researched the real world difference between these and slightly smaller widths.

 

The 235/40 are would be near ideal in terms of rolling diameter as the slight difference only brings the speedo towards being more accurate from the deliberate over-read that VAG have built in to speedos.

 

However, I will probably go for 245/35 not because of any performance reasons but because I can get Michelin PSS tyres in this size (OEM BMW size). In fact, many would argue that due to the static downward pressure on various tyre widths mean that the same car would have the same patch area between tyre and road - true, but they are applying a rather outdated and over-simplistic law of physics. Wider tyres do have some advantages in some circumstances (e.g.dry but not wet/snow) but any increase performance comes from tyre dynamics and adhesion principles (which do have some relationship to width) but are not directly related to width i.e. 2x width does not equal 2x traction. If anyone fancies making their head spin, then grab a coffee and try reading this http://www.f1technical.net/forum/viewtopic.php?f=6&t=9333 or any one of hundreds of other articles of debate on width vs. traction.

 

So in short, I would be better off spending the money on a good tyre and 245 width than rolling arches, camber plates and whatever else to accommodate a 255 width. If I could get the Michelin PSS (and if I didn't just commit to an 8.5J wheel  ) I would maybe go 235.

 

I really want to try the PSS - despite all the great reviews on the GY Assymetric 2, I was initially pleased but have been disappointed in the last 2 sets that I have had; they feel less grippy to me in the dry despite still being great in wet cornering. This goes against a lot of popular opinion so I will probably get flamed for saying that! 

 

The 245/35 will actually cause the speedo slightly over-read even more over the standard but there is a way to tweak that using VCDS 

[Brimma]

Congratulations for taking the risk on 245s

Let's hope it's not an expensive mistake

[muckipup]

The wheels have arrived.....

...now for the tyres. The wheels had a full width of just under 240mm and left about 6mm to the strut on test fitting even with being ET52. The outer edge looked to be a few mm inboard from the arches so I am hoping that a 245 tyre may just make it. I could always have spaced them out from the strut but never un-space them in from the arch!

There was loads of space over the Porsche 986 calipers due to generous spoke design of the Pro Race 1.3 which was a relief with ET52 wheels!

Will be back shortly with an update - wish me luck and don't say "I told you so". I know it can be done now....the arches were slightly rolled but Toddzy looks lower than me and his wheels were ET45...

http://www.vwgolf.net.au/showthread.php?6036-Skoda-Octavia-vRS&p=350649&viewfull=1#post350649

[Norco]

Looking forward to seeing this one. 

[muckipup]

245/35/18 tyres are on! Now to see if they fit this weekend or if some modification is needed!

[rob_e]

good luck

[muckipup]

The wheels and 245/35/18 tyres went on with hardly any drama! 

 

The only thing was that the inside edge of the front tyres just touched the suspension strut by a whisker due to the few mm of lip that the Michelin PSS have; a 2mm spacer solved this problem. There was loads of room at the back without the need for a spacer although I put a 5mm spacer on just to tweak the overall look. No rubbing at all now. If I could have had an ET50 wheel instead of the ET52 of the version of the TD Pro Race 1.3 wheel that I had then I could have avoided spacers altogether.

 

The end result was a wheel that cleared the suspension on the inside and a long spirit level showed that the outside edge of the tyres at their widest part was exactly in line with the outside edge of the arches both front and back (with the 2mm and 5mm spacers respectively). It is important to note that the Bilstein B12 dampers and Eibach springs mean that the car is not much below stock VRS ride height. If it was, I would need to do the 'arch screw mod' at least and if really lowered then start playing with camber or rolling out the arches.

 

I am glad that I did not go with the 255/30/18 tyres - that extra 10mm would have meant that I had to space out a further 5mm to clear the strut i.e 7mm (if there is a 7mm spacer) on my ET52 wheels and the extra 10mm of poke beyond the line of the wheel arches would have been too much for my liking and risked significant damage to the arches with a big enough bump (even with my generous ride height). I just can't see how 255s would work without a lot of arch bending, arch liner removal and camber and would be silly on anything less than ET50 wheels.

 

Haven't had a chance to push the car and test what the wider tyres give or take in terms of handling.

 

 

 

 

 

 

[TsvRS]

Very nice

[philbes]

Those Michelin PSS tyres certainly give protection to the wheel rim; or does the profile of the actual rim also contribute to the 'overhang' of the tyre..

[muckipup]

Those Michelin PSS tyres certainly give protection to the wheel rim; or does the profile of the actual rim also contribute to the 'overhang' of the tyre..

It is really down to the rim protecting lip on the tyre; they remind me of the Goodyear Eagle F1 Assymetrics that just came off the car which have similar rim protection and which has been most welcome on a few occasions!

[rob_e]

looking good.  any pics showing the whole car?

[necolove]

Interesting...

I'm thinking about a 245/35 tyre with the new RS230 (225/35 fitted from factory) and all I see is 235, you're the first brave one I found going further.

It's been a while since this, still on same tyres or did they give you any problem?

I'm not planning to touch springs (shared with my wife, and DCC fitted... Not the best escenario) so "plenty" of room in the archs. Looking for aesthetics, filling those archs, and confort, with little more profile.

Cheers.

Edited 5 September, 2016 by necolove

[Ecomatt]

There wont be a massive amount of difference with grip as it is only an extra contact patch of 20mm making 80mm in all. You will have to play around with pressures to find what suits best as the std pressures will be way out due to the internal area now being larger. Either way you have a nice looking car ????