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Re: 16" vs 17" wheels
[Re: Trappy]
#1464628
20/12/2013 17:19
20/12/2013 17:19
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Joined: Dec 2005
Posts: 12,296 Sandhurst
Begbie
ex El Presidente
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ex El Presidente
I AM a Coop
Joined: Dec 2005
Posts: 12,296
Sandhurst
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Fantastic thread guys. This has certainly got me thinking. I really do not want to spoil the handling of the car when moving to 17" wheels so this is all good stuff! For instance i am thinking of going with the same wheels as Begbie and his are a 35ET Good luck with that. I looked into the Compomotive MO5 after reading Nigel's suggestion and quickly discovered that the company has gone under. I REALLY wanted to get the MO1777 but they don't appear to sell them anywhere now ![rolleyes rolleyes](/forum/images/graemlins/default/grin.gif) Compomotive haven't gone under, just the company that made the wheels for Compomotive have gone under. Compomotive are still trading / finding a new company to make wheels for them.
Your car is Usain Bolt with wellies
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Re: 16" vs 17" wheels
[Re: Trappy]
#1464632
20/12/2013 17:47
20/12/2013 17:47
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Joined: Sep 2009
Posts: 5,058 ation
szkom
Club member 2000
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Club member 2000
Forum is my life
Joined: Sep 2009
Posts: 5,058
ation
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Sorry if I'm being thick, but if you were to buy a wheel style with an offest to match the installation in your diagram, would the wheel have more material on the back for the positive offest and less for the negative offset? It would indeed.
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Re: 16" vs 17" wheels
[Re: ]
#1464663
20/12/2013 22:12
20/12/2013 22:12
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Joined: Aug 2000
Posts: 9,729 Zele, Belgium
Kayjey
Club Member #10
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Club Member #10
Je suis un Coupé
Joined: Aug 2000
Posts: 9,729
Zele, Belgium
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I hope this explains it more - without having different style rims in the image. Here, there is a larger positive offset but less spoke clearance than with the one on the right (which has smaller positive offset but larger spoke clearance). And... here is the problem a bit with the Fiat Coupe... it has quite a large positive offset (40mm) but also needs large spoke clearance. The standard rims flow to the outside of the wheel (the spokes sit slightly proud if you lie the wheel on the ground with the backside on the surface), but many wheels have just straight spokes that don't go beyond the top surface of the barrel.
- Kayjey - ![[Linked Image]](https://www.fiatcoupe.net/layout/head_r2c2.gif)
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Re: 16" vs 17" wheels
[Re: ]
#1464815
21/12/2013 20:27
21/12/2013 20:27
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Chalky
Unregistered
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Chalky
Unregistered
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Kayjey is this why most people that buy the 17" team dynamic pro race 1.2's in a et 25 so there's room
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Re: 16" vs 17" wheels
[Re: ]
#1464863
21/12/2013 23:35
21/12/2013 23:35
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Joined: Aug 2000
Posts: 9,729 Zele, Belgium
Kayjey
Club Member #10
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Club Member #10
Je suis un Coupé
Joined: Aug 2000
Posts: 9,729
Zele, Belgium
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Pretty sure many items contribute to the handling of your car Nigel! Anything written above should not be taking as extremely affecting the handling or causing instant failure. But it contributes to the general feel of the car. Indeed I doubt it would be instantly noticeable, but having had the joy of comparing a 17 inch (ET unknown) with extra spacers added and how it felt reluctant to turn in (admittedly also 245mm wide I believe and not the lightest wheels either) - and then the transformation and how much lighter and agile it felt on the way back...
Anyways... I always tend to be part of the gang that thinks a manufacturer has a lot of reasons to make a car as it is, and if you want to enhance the performance and handling, it'll be a case of meticulously investigating, measuring, trying and analysing (*). Trial and error WILL get you far, and the benefit of scale and many people trying different things here is a Big Plus. But I just want to say that there ARE drawback and you can't just lower the car 5cm, beef up the dampers and springs and get a 20mm wider track without affecting anything else.
Eg. as we've seen (and I believe you yourself were part of the thread) you can beef up the suspension to the point where you get rid of any compliance of certain parts (to the benefit of handling) but then concentrating the strain of the forces going through it all on other points which may then break or suffer wear. As said - a manufacturer will compromise on ALL parts, and if you want to get the best you will have to optimise ALL parts. People who run slick tires know which strains it can put on bearings, welds,... because of the added grip.
(*) Talking 'regular' cars here, not homologation specials where they deliberately turn down the power / disconnect extra injectors / ... I'm thinking Ford Cosworth RS500 for example, RX-7,... where a couple of magic tricks can do wonders because the manufacturers already prepared them for racing reasons.
- Kayjey - ![[Linked Image]](https://www.fiatcoupe.net/layout/head_r2c2.gif)
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Re: 16" vs 17" wheels
[Re: Kayjey]
#1488122
14/05/2014 15:43
14/05/2014 15:43
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
Forum is my life
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Forum is my life
Joined: Feb 2006
Posts: 5,390
Essex
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I've been thinking about wheels again and got so fed up with the whole offset, track, caliper clearance thing, that I've drawn it p for my own clarity Sick of seeing these types of images on the internet, I've tried to add some points of reference... i.e. car wheel arch bodywork, brake caliper, brake disc and, therefore, wheel mounting face. I've done it for two wheels and (hopefully) it represents the difference between a standard 20vT wheel, and one of Nigel's wheels. Standard wheel 7x16" 4x98 34ET 58.1CB Team dynamics 1.2 7x17" 4x98 25ET 58.1CB One of the things I found difficult to grasp was why a bigger offset brough the wheel into the car. I get it now! I have also gained an appreciation of caliper clearance and now see that an important measurement for us, is the distance between the inside of the spokes and the wheel's inner mount surface. I measured it on my spare wheel set last night and it was 47mm. The caliper must stick out miles! Another thing that was being touched on in this thread, was the increase in track due to an decrease in ET. Is it a fair statement that (for a wheel of equal width) the track increase by the same amount that the ET decreases? I'm thinking a spreadsheet for wheel fitment will be created shortly... ![idea idea](/forum/images/graemlins/default/idea.gif)
F****** b****** thing...
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Re: 16" vs 17" wheels
[Re: ]
#1488541
17/05/2014 06:30
17/05/2014 06:30
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nissansteve
Unregistered
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nissansteve
Unregistered
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Going on with rolling circumference. It's easy to tell the difference on my lorry.
Our trucks are limited to 52mph. My truck with worn tyres would do 51mph. I had new rear tyres fitted and can now do 53mph.
I overtook another one of our lorries and when I got back to the depot, the other driver was complaining my truck was faster than his. When I told him it was because I had new tyres fitted the whole place errupted in laughter.
They just couldn't understand the idea of a larger rolling circumference. I had to draw a picture in the end.
The difference is significant on a lorry tyre. My new tread depth is almost 25mm plus they can have grooves cut into them as they wear down. In effect reducing the circumference massively. Thereby reducing the maximum speed irrespective of the speed limiter. Which is why the tacho is calibrated fairly often.
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Re: 16" vs 17" wheels
[Re: ]
#1489176
20/05/2014 18:08
20/05/2014 18:08
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Joined: Oct 2008
Posts: 6,783 In the coupe.
magooagain
Club Member 259
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Club Member 259
Forum is my life
Joined: Oct 2008
Posts: 6,783
In the coupe.
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Ok at last i have found a set of compomotive rims. They are 17 inch 98x4 with an ET 37.
Can anyone confirm that they will fit over the Brembo's please?
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Re: 16" vs 17" wheels
[Re: ]
#1489201
20/05/2014 19:44
20/05/2014 19:44
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patch234
Unregistered
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patch234
Unregistered
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With that ET they should Joe. But I don't think anyone can say a resounding yes to your question! Is it possible to test fit?
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Re: 16" vs 17" wheels
[Re: ]
#1489202
20/05/2014 19:49
20/05/2014 19:49
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Joined: Dec 2007
Posts: 2,252 Windsor/ Reading
knight7660
Competition Level
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Competition Level
Joined: Dec 2007
Posts: 2,252
Windsor/ Reading
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Well the ET of a standard wheel is 34 so you'll be cutting it to close because you need a lower ET number to bring the wheel/spokes away from the caliper.
If my thinking is right they won't clear but I could be wrong
LE53 (452BHp & 389ftlb's with Quaife) Wine red VIS FOOFY Audi RS4 B7
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Re: 16" vs 17" wheels
[Re: ]
#1489319
21/05/2014 11:50
21/05/2014 11:50
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Joined: Dec 2007
Posts: 2,252 Windsor/ Reading
knight7660
Competition Level
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Competition Level
Joined: Dec 2007
Posts: 2,252
Windsor/ Reading
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But aren't the k sport calipers smaller in height but longer in length if you know what I mean. Standard calipers bulge out towards the spokes etc
Last edited by knight7660; 21/05/2014 11:51.
LE53 (452BHp & 389ftlb's with Quaife) Wine red VIS FOOFY Audi RS4 B7
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Re: 16" vs 17" wheels
[Re: ]
#1489330
21/05/2014 12:43
21/05/2014 12:43
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Joined: Oct 2008
Posts: 6,783 In the coupe.
magooagain
Club Member 259
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Club Member 259
Forum is my life
Joined: Oct 2008
Posts: 6,783
In the coupe.
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The wheel model number is MO1783 ET 37 17 x 8 inch.
I think i am going to take the coupe for a trial fit. Or are 8 inch to wide?
Last edited by magooagain; 21/05/2014 12:45.
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Re: 16" vs 17" wheels
[Re: knight7660]
#1543529
02/07/2015 10:23
02/07/2015 10:23
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
Forum is my life
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Forum is my life
Joined: Feb 2006
Posts: 5,390
Essex
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Seems like only a few months back that we had this conversation... Anyway, here's a good website that allows you to tinker with the variables of a wheel to see how it all works and what it actually means. Helps my simple brain no end!!
F****** b****** thing...
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