meanmx wrote:I'm not wishing to add to an argument or to sling sh*t but I do have a couple of questions after reading that link that Jeo kindly supplied us.
Ok, first I understand that less weight is better.
Good start.
But when you split that up into how much the wheel weighs and where that weight is on the car things get more complicated.
Sure, but both are bad, no matter what, for both grip, feel and comfort, and there isnt a single person who likes cars who doesnt care about one of those things, usually all 3 are important to people.
So if you are talking an extra 2kg per corner which is probably the difference between equally manufactured wheels of 15" and 17" are you really going to notice that much significant difference on the road where you shouldn't be driving at 10/10th's anyway?
Absolutely, its not just about ultimate grip, as said, its about feel and ride comfort also.
How do you measure that difference unless it is completely dependant on how that one person feels. I had for a short period of time 17" chrome wheels on my NA that I borrowed, and this is where I completely understand what you guys are talking about.
Excellent.
The handling was completely changed for the worse, however going from the stock 14's to normal 17's I was ecstatic with the extra grip on the road, better turn in, and the feeling of being more connected.
You went from an aged 60 profile tyre on a 5.5" rim to a new tyre, probably a performance tyre in a 45 profile on a 7" wide rim (or wider), nobody is surprised that this combo felt better than the old one.
To me I felt very little detrimental difference which I guess is why I'm still running 17's (although not chromies). How do you judge that point at which you tell someone it wrecks the car, as I never felt on the road that I was impacted and certainly wasn't left behind on any mountain/ coast runs as other people can testify.
You arent comparing a 15x8+35 with good tyres and a stiff sidewall to a 17x7+20 with good low profile tyres you are comparing whatever tyres your car came with in a 14x5.5 60 profile to a 17x7 45 profile with good tyres, its not a fair comparison, and its not what others in this thread are comparing.
The second part of this question is in regards to where that weight sits. From what I can gather the wider a wheel is and the lower the offset then the more detrimental to a cars performance it is. For example a 15x7 40 offset would be better than a 15x8 20 offset which would in turn be better than a 15x10 20 offset. This is because the weight will be pushed further out from the body which means the suspension can't deal with it and it places more strain on the drivetrain thereby affecting performance. Is this correct? At what point is the extra grip due to wider tyres offset by the extra rotational mass that is now sitting further from the hub?
Its not correct. Although its true that a 15x7 with a low or negative offset will perform and feel worse than a 15x7 with the correct offset, adding width and keeping correct offset ALWAYS performs better regardless of weight, however it will ride worse with more weight. Once you have enough width and grip that your drivetrain cannot overpower the tyres adding extra width doesnt help, however.
Why aren't most of you racers running 14's? Is it brake related or tyre choice related? Reviewing the information it would seem that a light weight brake setup that will fit under a 14" lightweight wheel would be the goal. Is it lack of availability and if so then how do the mini guys do it?
Its brakes and tyres. The NB8B brakes are the smallest acceptable brakes on a full (or close to full) weight NA/NB racecar, and these dont fit under 14" wheels, along with the fact that performance tyres are much cheaper, easier to get and have many many more options in a 15 over a 14.
Mini guys get away with 14s because the car came with 13s and they weight even less than an na6, so they dont need as much brakes. However get to a hillclimb with honda swapped minis and you will see a bunch of 15" equipped minis.
Why is it that no modern designed sportscar have these sizes stock. Admittedly not many are as light as an mx5 but there are still several cars almost as light. Think Porsche Boxter, Lotus Elise, Toyota 86, KTM X-Bow. If it is brake related as some people think then surely the manufacturer feels that brake size is more important than wheel size. If it is a marketing strategy then surely it is just as important marketing wise to have the best 0-100, 1/4 mile, lap time as well. All I can think is that the manufacturers of these performance cars must feel the compromise is worth it.
You are trying to predict marketing with no background. there are a few things, modern performance cars have much bigger brakes, on top of people like yourself who think 17s are the go and 20s are even better. the 1/10th of a second gain in 0-100 with 15s is not worth all of the people who wont buy a sports car that doesnt come with a 17" or20" rim package as standard.
A great mx5 related example is the SE, which comes with 17s and is very well known to be upgraded to a 15x8 for ride, feel, and grip.
Another is the strut brace that comes on later model mx5s such as the OEM ones on NCs, look at Targa Racing's NC race cars which haul arse and put down amazing consistent lap times, you will see that the strut braces are left off to save the 4 nuts and 2 minutes it takes for maintenance.
I'm not trying to start something or insult anyone. If anyone feels insulted then I apologise right now to them. I just want to increase my knowledge after reading all those links that Jeo posted. Ultimately I will never be swayed into a wheel choice by anything that anyone says here unless I decide to go racing but for street use I will buy whatever I feel like as long as I feel that it is right for me. I was contemplating going 16's to get that whole JDM thing happening a little more but I'm now pretty sure I will get 17's again as I feel the look is right. Hoping that the information posted will be informative for myself and others providing people can stay away from personal opinion and forum heresay. I'd love some genuine facts rather than you should run this because it's the best.
What I have provided above are all genuine facts, echoed by thousands of long term mx5 owners and enthusiasts worldwide.
Just for shits and giggles, F1 cars run 13" rims. They have amazing brake technology and weight 500kg so can get away with the smaller brakes.
Dann
