Hi guys,

I would appreciate your views/opinions on changing my original 205/55/16" wheels with the larger 225/40/18" (BBS-RC alloys). The reason i would like to proceed this way is that I get alot of wheel-spin with 1st, 2nd, and on changing to 3rd gear when reving above 3-3.500 rpms. I just undermine that the car was measured last year and produced 210hp/300Nm with a broken DV realized some days later and currently has some newer mods like a free-flow cat-back exhaust and must have therefore some more power, as it is felt like this.

Will the 225/40/18" wheels slow the car down and will they reduce wheel-spin to a more acceptable level? Is it worth the money, or losses will be greater than gains? Should I compromise in between and go for the 225/45/17" wheels?

Any input will be welcome by all of you in this forum:)

Thanks

I would think you would actually get more wheelspin with the lower profile tyres since the rolling radius (I assume you have calculated it this way) is not changing, therefore neither is the torque at the wheels causing the wheelspin. The standard tyres will absorb more of the torque before losing their grip. JMHO.

Chris,

should you be going to 225/45/18 as opposed to a 225/40/18 to keep the rolling radius the same? That said the difference may be too small to make a difference on the speedo.

With the wider tyre you would get better grip generally but I don't know about standing starts. Assuming the rolling radius are the same, the torque will be the same at the wheels. There will be more surface contact area due to the wider tyres so I would assume that there would be more grip.......perhaps?

I'm sure those in the know will steer you right.

Cheers.

Adrian.

18s would look the daddy in my opinion, compared to 16s. I imagine it would corner better too as the tyres will be wider, and there would be less sidewall flex in 35s compared to 55s.

Don't go by my opinion though, as I'm no expert. What I do know is my current setup (205/40*17) is much better than the standard 185/60*14 the car came with.

Grip should be increased due to the wider tyre having a bigger foot print.

I am looking at 20" wheels for my vRS but designs are limited so may go for 19's. (My friend owns a alloy wheel and car accessory shop so can get some wheels at cost)

The change from 16 to 17 or 18" does not improve the grip.

What is important is to choose a more high performance tyre

that is stickier and has softer compound.

If you choose cheap heavy wheels and tyres acceleration and

comfort will suffer but the "racing image" will be better.

I'll second that, Eric. I admit I ignored the extra width in my first response. Still trying desperately to wear out my cheap slippy tyres so I can get some grippier ones - only another 10k miles or so to go :( (Of course the paradox is that being cheap and hard, and therefore slippy, they last longer and can't be got rid of so quickly )

You're not trying hard enough Nick...

Rob.

Trying too hard + slippy tyres = hedge

Originally posted by SkodiRS in this post

Chris,

should you be going to 225/45/18 as opposed to a 225/40/18 to keep the rolling radius the same? That said the difference may be too small to make a difference on the speedo.

With the wider tyre you would get better grip generally but I don't know about standing starts. Assuming the rolling radius are the same, the torque will be the same at the wheels. There will be more surface contact area due to the wider tyres so I would assume that there would be more grip.......perhaps?

I'm sure those in the know will steer you right.

Cheers.

Adrian.

Thanks Adrian...!!!

The rolling diameter of the wheels are as follows (according to my calculations):

205/55/R16 = 631.9 mm

225/45/R17 = 634.3 mm

225/40/R18 = 637.2 mm

So the difference in rolling diameter between 225/40/R18 and 205/55/R16 is 5.3mm (rolling radius difference 5.3/2=2.65mm), while the difference between 225/45/R17 and 205/55/R16 is 2.4mm (rolling radius difference 2.4/2=1.2 mm). I think that rolling radius differences are negligible in both cases, as you say.

Switching to 225/40/18 tyres should give better grip for 2 reasons.

1.Wider tyre footprint = wider area to disperse torque.

2.tyres in this size tend to be "Sport" orientated and will usually have softer"Grippier" compound,

Guess I will find out soon myself -- collected my Kahn RS-S 18's today - will also be using 225/40/18 rubber....time will tell

Dave,

post pics of your new wheels when you get a chance.

Cheers.

Adrian.

Originally posted by skodaw in this post

Switching to 225/40/18 tyres should give better grip for 2 reasons.

1.Wider tyre footprint = wider area to disperse torque.

2.tyres in this size tend to be "Sport" orientated and will usually have softer"Grippier" compound,

Guess I will find out soon myself -- collected my Kahn RS-S 18's today - will also be using 225/40/18 rubber....time will tell

I am running on 225/45ZR17 tyres and they are the crappiest, hardest, slippiest pile of :dung: I've ever had the pleasure .... Grippy, pah!!

Name and shame, please, Nick...

You would never have heard of them:

Fronts: "Star Performers"

Rears: "Roadhogs"

Equally :dung: ... but tight@rsed old me is waiting til they are worn out before getting better rubber - it's my business as well as my pleasure, after all ...

Let the pleasure win over business this time, and get yourself TWO super-grippy new tyres.

Mount them on the front, and dump the old ones in the boot.

Get the car to a (Briskoda-organized?) airfield track day and smoke those b*ggers at the rear!

If the tyres are really that bad and gripless (and with another two heavy piles of crap in the back), this set-up should equal mega-drifts and instant RWD-style fun. Rears gone? Mount the pair in the boot and carry on where you left off but leave enough profile for a careful drive home.

Then buy another pair of grippy tyres and put them on the rear for continued safe but more enjoyable motoring.

(Ah, but you aren't the car-hooligan type, are you? )

When I said most tyres of that size were of a sportier nature -- I didn't think anyone would be so tight as to use recycled rubber bands as tyres.........

Originally posted by Dutch4x4 in this post

(Ah, but you aren't the car-hooligan type, are you? )

I guess not - have never taken my car on track - don't want to write it off with no insurance. I need it to get to work and back.

Originally posted by skodaw in this post

When I said most tyres of that size were of a sportier nature -- I didn't think anyone would be so tight as to use recycled rubber bands as tyres.........

Just running the tyres that were on the car when I bought it. When I looked it over the two rears were just about dead. Then when I picked it up, lo and behold the dealer had fitted two new ones (the "Star Performers"). Kinda goes against the grain to throw them away when brand new. Now 20k miles later they're two thirds worn ....

I know what you mean,having just had to fork out for 4 18" tyres.Although I think I got a cracking deal from the company my dealer uses - 4 225/40/18z Conti Sport Contact 2 for

Thanks for all your answers guys... Your input is much appreciated...:cheers:

The other issue I'd like to bring into discussion is whether the 225/40/18" wheels will slow the car down off the line compared to 225/45/17" or 205/55/16" wheels.

P.S. I'm planning to put 225/40/18" wheels with BBS-RC alloys (very light and resistant) with Michelin Pilot Sport or Goodyear Eagle F1-G3 tyres...