Help with wheel offsets

[Kirsty80 16]

The whole wheel offset confuses me, can some one help me out.

The car is standard hight and I just want to bring the wheels out level with the arches.

I've been looking at work emotion D9R.

Also is it best to stay 17 x 7 or go to 8?

Again I haven't a clue about offsets for either widths.

Any help would be much appreciated 😃

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[S18 RSG 429]

Stock offset is around 45 I believe. A 35 offset wheel of the same width would be 10mm further out. An 8 inch wide wheel (one inch wider than stock) with 45 offset would be half an inch further out (offset is the same, so half the width of the wheel comes out, half goes in).

You can safely go up to 9.5 inches wide, with as low as a 30 offset without worries, however, if you have stock suspension the limit will be much lower due to the inside of the wheel hitting the strut. I think 8.5 inches wide is about the limit with stock offset. Lower offset helps greatly in that situation.

Hope that helps.

[Deacon 1357]

Stock offset is 48. On stock suspension you can pretty much fit what you want but if you ever want to lower the car at all that will alter your choices as with lowering springs you'll have to be really carefull with anything above about 8.5 inches wide or you'll foul the suspension. Coilovers give you a lot more freedom as by their nature they are smaller and the springs stick out less giving you more room for wheels.

If you fit new wheels you will want to lower it too as non standard wheels do seem to look a bit silly/weird with stock ride heights.

I have 17x9 et42, 17x7 et40 and 17x7.5 et35. The 17x9's fill the arches the best then the 17x7.5's and the 17x7's the least.

My suggestion would be to look for a 17x8 et35 as that would do a pretty good job of filling the arches nicely as it brings the wheel edge out 25mm bit doesn't go any closer towards the strut.

If you're not lowering and go for at least 8" wide wheels you could also fit a 235/45/17" tyre which will raise your ground clearance 10 mm but also take away 10 mm of arch gap giving the same effect as if the car was lowered 10mm. These will lose a little precision due to the extra sidewall height but will also gain you a little comfort from the extra compliance. They'll also almost correct the speedo read error so when it says 50mph you'll actually be doing pretty much 50mph.

This site is really good to play around with:-

www.willtheyfit.com

Hope that helps too!

[Kirsty80 16]

Thanks for the help (still rather confused 😂), it will be lowered eventually, I just want wheels first as the stock ones are awful haha.

I think I'll take a look at what I can get in 17x8 35 as you said above Deacon, as lowering won't be for a while and I just want something new on.

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[Riceburner 284]

I found this quite usefull

 http://www.willtheyfit.com/#isPage=1

 

 

[Tareim 343]

this site is the best for us to decide if a wheel will fit, just stick in the wheel specs and see how it sits

http://frsproject.com/

[KevinA 695]

Just pop round got bloody wheels everywhere 

[Kirsty80 16]

Just pop round got bloody wheels everywhere 

Haha 😂

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[STEVO9000 54]

I run 18x8.75 et35 fills the arches perfectly on mine, near enough flush tbh  

[Lauren 2259]

17x8 with an offset of 38 is what I have. Works perfectly. Be careful with your wheel selection, check the weight of the wheels. Stock are heavy at 9.2kg. Try hard to get lighter wheels than that as the benefits are well worthwhile. 

[Kirsty80 16]

17x8 with an offset of 38 is what I have. Works perfectly. Be careful with your wheel selection, check the weight of the wheels. Stock are heavy at 9.2kg. Try hard to get lighter wheels than that as the benefits are well worthwhile. 

Will these fit with standard suspension Lauren?

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[KevinA 695]

Different Sizes and offset, but they look vey similar.

[Lauren 2259]

5 hours ago, Kirsty80 said:

Will these fit with standard suspension Lauren?

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Yes, absolutely fine, no problem at all. 

[Keethos 842]

I'm going to have to disagree with Lauren and say don't worry about the weight of the wheels, I'm assuming you won't be chasing 10ths off lap times etc so I wouldn't worry about the weight of the wheel, it should be a bonus if they are lighter, not a major consideration.  I tried to find nice light weight wheels specifically for track use and I wasted a lot of time, it severely reduced my choice of wheels.  They were either relatively light but not very interesting look wise or they look really nice and were light weight but were mega expensive.

As for fitment, what people have suggested is fine, to hopefully clear up some of the confusion, the offset is from the centre of the wheel to the mating face of the wheel hub, so if your wheel is 8 inches wide, the centre line is 4 inches in (i.e. down the middle of the wheel) which means when the stock wheels are +48mm further out from the centre of the wheel, the wheel sits further into the arches, if you get a wheel with a +30mm offset, this means that the distance between the centre line of the wheel and the wheel hub has reduced which would mean then the wheel should sit further out:

 

Hope this helps.  As mentioned, the http://frsproject.com/ website is great to check this out and play with the wheel info to visually see roughly how the wheel would sit.

[Tareim 343]

8 hours ago, Keethos said:

Hope this helps.  As mentioned, the http://www.frsproject.com/tire_size.php website is great to check this out and play with the wheel info to visually see roughly how the wheel would sit.

I've already posted that link earlier Keith  also you need to update that link as the site has been updated and no longer works if you include the /tire_size.php

[KevinA 695]

Pretty much agree with Keethos and Lauren, if your competing then there will be a small advantage with a lighter wheel but it's not night and day. I ran what people call heavy wheels and still produced good results, best go with what you like and choose what suits your needs.

[S18 RSG 429]

Really glad people are preaching what I have been for a long time. Far too many people are being told that they need lightweight wheels, and it's limiting people's originality with the car.

I've always told people the first consideration when buying wheels is design. Decide on design first, then shop around to see what options there are in your budget. You then decide on colour and size, then when you've narrowed it down to a shortlist of what you want, you pick the lightest ones.

So many people are being told that they need to search by weight first, and that's just so wrong. In the real world, when 99.99% of driving is done on a public road at normal speeds, weight of wheel means about as much as what you had for breakfast that morning.

Scrap all of the above if you're building a track car, or if you really REALLY care about getting approval from a handful of people for how light your wheels are 😃

[Church 209]

I disagree somewhat. While i didn't notice much of change by my 'butt dyno' in acceleration/brakeing, but i did notice more comfort/better suspension working (in daily street driving on less then ideal roads here), when i dropped one third of wheel weight. And luckily i love the looks of my current TechniCraft (Taneisya) T6 wheels in addition to weight savings. Win-win, i'd say.

[S18 RSG 429]

As I've mentioned before, I, multiple others, and various lightweight wheel tests in magazines over the years have found the opposite, that heavier wheels have provided a more compliant ride. I gave an explanation of potential reasons behind this in another thread, but point being, I don't think it can be used as a definitive positive when people experience different results.

[Church 209]

Heavier wheels - more compliant? How so? Rotational weight aside, which should impact accel/deccel, unsprung weight reduction means that same dampers/springs have less mass/inertia to overcome when moving wheel over road bumps, so wheel hops less, lowers sooner in roadholes, adding slightly grip and comfort. I fail to see how heavier weight can do the opposite of what logic tells it should, when even my butt dyno feels same as what should be by logic.

[S18 RSG 429]

Actually, logic suggests that a heavier wheel requires more energy to be lifted off the ground, meaning a heavier wheel is kept in contact with the ground more of the time as it's less likely to lift over small bumps, whereas a lighter wheel requires less energy to lift, and therefore a small bump can lift the wheel easier. This means that even quite small bumps can unsettle the suspension with light wheels, and require the suspension to work harder to keep the wheels in contact with the ground.

I see where your logic is taking you (spring can compress and decompress easier, and therefore faster, because it has to shift less weight), but remember, a coil spring is always compressed. If you hold a spring from the top, compress it, and put a small weight at the bottom, it will decompress at a certain rate. Increasing the weight at the bottom encourages the spring to decompress more quickly, as it decompresses downwards, and the gravity acting upon the heavier object pulls the spring down more quickly.

Not saying this is massively relevant in terms of a car, but just explaining the theory.

[Church 209]

Initially more energy to lift off, yes, if it's within range of what tire can flatten a bit. But if it's more >1cm and wheel itself starts moving? And it wont work other way around, with roadholes, as tire rubber can widen very little, max few mm, so with heavy and thus inert wheel it will just hop over hole in air. I recall how it was touted for hydraulic bumpstops for new Teins, that how good and well it is, with wheel more of a time in contact with ground and quicker setling after bumps/holes .. i believe it works same way (just no matter what suspension) with lighter wheels. And it's something i feel driving too and hence find very hard to believe mention that by those magazine tests it's other way around.

[S18 RSG 429]

Well listen, I'm not gonna continue to argue over the theory. That previous post was basically entirely written by a senior colleague of mine with a mechanical engineering degree, and there's still opposition against his point so there's little point in me adding to it. Let's just agree to disagree on the theory.

You feel benefits one way, I feel benefits the other way, let's just be happy that we're both individually happy 😃

[Church 209]

I've seen engineers of somewhat similar field fail when applying their experience to supposedly distantly related field. For example someone designing at manufacturing plants high pressure hydraulic lines and then designing and assembling own PC liquid cooling loop of subpar configuration/performance, needlessly overcomplified due redundant parallelising of each and every component. There are also cases of doctors being among worst possible patients, as they "always know better" then doctors of some exact field that treats them. Since such cases i don't take always for granted everything told by engineers as absolute truth in last instance, unless they are engineers of that very field, for example car/suspension engineers in this.

But yes, this goes too far offtopic, and no sense to fight over if we have different subjective experiences

[Darth Raknoor 1]

Hello everyone, I'm new here and  will be getting my 2020 gt86 soon. I'm looking to get some Advan TC-4s in 17x7.5 and wanted to know if they'd fit. 

Which from this list of 17x7.5 would fit best?