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Discussion Starter #1 (Edited)
Hello guys, I have new tires, Just for 5 days now.


I have to write few words, because this was very good buy I believe.


They are 205/45r17 Fulda Sportcontact 2. Rims are 7x17 ET42, both. Yes, I know this is big size for UP.
Previously I had Falken Ziex ZE914 215/40r17 tires.


Suprisingly, new Fuldas are 10mm wider (though they are narrower in numbers). This may give you idea how misleading these numbers can be.


Overall wheel diameter is 4,3% bigger than my stock 185/50R16
Speedo is indicating fine, still 1-2kph more than real speed (GPS)
Rear fender fit is good, rear fender is big fender. I was lucky with front fender fit, it may be about 2mm clearance on inner and outer side, but no scratch noticeable. Only small parking scratch on full turn, and you can’t hear it. The tire is touching the front-inner plastic. I will make a hole after 50kkm, IDGAD, I will replace it.


Tyre performance is very impressive. In every aspect better than Falkens. They are superquiet, economical, they are quite soft and comfortable, this is more important than I thought (in 900kgs weight car). Falkens had tough walls for heavier cars and precision sport driving. You don’t need this in Up, it’s ruining your spine.


Today on big parking space I tried to test how the ESP is performing. I was doing moose test and big circles, quite big forces but the girp is great, this was hard to hear the ESP, there was no bad behavior at all.
Braking force on wet was very good, on dry it was even more impressive, I liked it much. They are very safe and predictable.
I also came back to my previous fuel economy that I had on my winter wheels (Kumho Wintercraft wp51 185/50r16). Maybe it’s even 3% better now. On falkens this was disaster. They were big energy wasters. They were 10% worse in this economy. And really solid 10% every time, not telling 12%. Hard to believe, but yes.


Final gears ratios on 75hp gearbox are still fine, not very big difference. I like it.
Are these big oversize wheels better? Yes they are better. Car is more stable, it’s going more confident on high speeds. I’m going faster on inter-city roads. And with these Fuldas this is 10x Yes. I’m very happy right now :)
 

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Discussion Starter #2
Error! not Sportcontact but Sportcontrol. Fulda Sportcontrol 2. Continentals are named SportContact.
 

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Those higher profile tyres look horrible on the up!, it's too small and now looks like a roller skate. Sorry!
 

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Discussion Starter #8
You may like elegant and more refined things, style, but sometimes things are different that they seem. In my opinion UP was not designed as a refined car, because this is not an E-class Mercedes. The evidence for this are the large, swollen fenders designed for large wheels. There are also reasons to assume that the original artistic projects envisioned large wheels, larger than they are on sale. Sometimes what we think is good, is just a habit from everyday views. What's the truth? I do not know myself. It will come with time. The Gti prototype’s picture I am attaching has 18inch wheels. All prototypes have bigger offset for wheels. Once again - more go-kart than Silver Spur Bentley.
 

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All concepts are always over-wheeled, it's a fashion thing which is supposed to reflect sportiness. But in the real world most of the time the truth is opposite.

Example: my MX5 can easily fit 18" or 19" wheels under the arches with no issues. But i wouldn't change up from the standard 17" because i'd lose sidewall and have heavier wheels wrecking the ride comfort and acceleration. It's already well acknowledged that the Up GTi isn't the first word in suspension compliance so any help you can give it is welcome, by putting bigger wheels and tyres the suspension is now having to work that much harder to control the forces in play. I already think that the 17s are a step too far as the rubber band tyres they deem "sporty" just end up being annoying after a while, i know if i had kept mine i'd have been looking for smaller wheels.

Or you can be a slave to fashion. But if you are truly interested in making a better driving car then imo you're heading in the wrong direction. You have a 75bhp, 900kg car and any unsprung weight you add to that will have a huge effect. But i'm assuming i'm talking to myself here.
 

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All concepts are always over-wheeled, it's a fashion thing which is supposed to reflect sportiness. But in the real world most of the time the truth is opposite.

Example: my MX5 can easily fit 18" or 19" wheels under the arches with no issues. But i wouldn't change up from the standard 17" because i'd lose sidewall and have heavier wheels wrecking the ride comfort and acceleration. It's already well acknowledged that the Up GTi isn't the first word in suspension compliance so any help you can give it is welcome, by putting bigger wheels and tyres the suspension is now having to work that much harder to control the forces in play. I already think that the 17s are a step too far as the rubber band tyres they deem "sporty" just end up being annoying after a while, i know if i had kept mine i'd have been looking for smaller wheels.

Or you can be a slave to fashion. But if you are truly interested in making a better driving car then imo you're heading in the wrong direction. You have a 75bhp, 900kg car and any unsprung weight you add to that will have a huge effect. But i'm assuming i'm talking to myself here.
Not to me, you're absolutely correct. After 48 years of driving and having been competing in road and stage rallies for 20 years of that period, reducing unsprung weight makes the car more agile, feel better, and hence you go faster, and can control it better.
There is a limit to where you can go with wheels and tyres, dependent on the design of the car.
Yes, you can go up a bit on tyre & wheel width by one, or maybe in some cases two sizes, but thereafter it doesn't do anything to enhance the performance of the car, in grip or handling.
In fact it starts to detract from the abilities of the base car.
Too much tyre means that the tyre moves on the rim in corners and the steering feel is ruined. Too big a width or diameter of wheel has the same effect, putting too much rubber on the road for the size or capability of the chassis. Again, bigger wheels & tyres mean more weight, and ruin the steering feel.
This reduces your confidence in the handling and you go slower.
There are of course, thousands of the younger generation that want what they feel is "the look", and aren't interested in how it affects the performance, and good luck to them, we've all been there when we were younger.
However, what they'll learn is that bigger ain't necessarily quicker.
 

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Discussion Starter #12
Not to me, you're absolutely correct. After 48 years of driving and having been competing in road and stage rallies for 20 years of that period, reducing unsprung weight makes the car more agile, feel better, and hence you go faster, and can control it better.
There is a limit to where you can go with wheels and tyres, dependent on the design of the car.
Yes, you can go up a bit on tyre & wheel width by one, or maybe in some cases two sizes, but thereafter it doesn't do anything to enhance the performance of the car, in grip or handling.
In fact it starts to detract from the abilities of the base car.
Too much tyre means that the tyre moves on the rim in corners and the steering feel is ruined. Too big a width or diameter of wheel has the same effect, putting too much rubber on the road for the size or capability of the chassis. Again, bigger wheels & tyres mean more weight, and ruin the steering feel.
This reduces your confidence in the handling and you go slower.
There are of course, thousands of the younger generation that want what they feel is "the look", and aren't interested in how it affects the performance, and good luck to them, we've all been there when we were younger.
However, what they'll learn is that bigger ain't necessarily quicker.

You are both right I am slave of my visual concept. I know that. Light car is even worse with too heavy wheels because chassis is reacting more. And UP is light. Higher tyres can compensate heavy rim problems, like in trucks.
I would go for 15x6.5 inch Sparco Assetto Gara, they seem to be very light. I would buy 195/55r15 tyres, I thought about this.

There is one problem, Up looks like Mr Bojangles' car on 15'' wheels with it's fenders. Maybe not so bad looking with supersport tyres like R888, some yokohamas, Dunlop Direzza, but they are loud and fuel consuming.


I just wanted to tell it isn't very bad now. It's suprisingly well handling and going, like on the railway road, or even a roller coaster, you don't want to push it to the end without bucket seats. I'm not any excited teenager, I had faster cars like 3.2 M3 E30 and have 3 years of my entry level rally experience plus many track day competitions with many trophys won. What about Ariel Atom? It weighs about 600kgs and front tires are 205 and rear 245. I didn' hear complaints.
 

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You must know that an Ariel Atom is a completely different ball game. It has 500bhp per tonne and needs big rubber just to hold it on the road. Thats not even remotely comparable.
We're talking about almost standard, or modified standard road cars here, and what we're saying about over-tyring and / or over -wheeling is well proven.
 

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Discussion Starter #14
You must know that an Ariel Atom is a completely different ball game. It has 500bhp per tonne and needs big rubber just to hold it on the road. Thats not even remotely comparable.
We're talking about almost standard, or modified standard road cars here, and what we're saying about over-tyring and / or over -wheeling is well proven.
Do you mean that heavier wheels car is loosing much of it's performance? My UP driving isn't rally driving. Neither it isn't drifting competition where you need much control over wheels spinnig speed. Wheel rotated mass isn't accelerating so very quickly while the car accelerating so I don't think this is taking much of the performance. There is final ratio change aspect only (and it isn't so big).
And about power to grip ratio - no I don't agree. Better grip is always better in your daily driver. You don't need 300hp UP to deserve better grip. You know you can achieve some level of speed with 75hp car and go like crazy on some curve sections, to the 95% of possibilities, touching the bark of the trees, and you are maintaining the speed, saving time. Ok, wheel mass optimization for racing, for rally - here I agree. Better optimization will do little better times. I would buy sportier tires for racing too. For my everyday use 5% of performance lost has no meaning. Too big wheel - maybe not so big deal.
 

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Unfortunately you have partly misunderstood.
If you read my post again, and interpret the reduction in unsprung weight not only as a weight reduction = more power to weight which = faster car, but also in the feel of the whole dynamics of the chassis, suspension, steering and thus the handling, with it's effect on your, and the car's performance.
I'm not "having a go" here, I'd be the first to admit that at 18 years old I put wider alloy wheels on my '65 Cooper S, and a twin pipe silencer, and thought it went faster.
I learnt through experience.
I also love driving low powered cars. I've had 60 bhp small cars, 240 bhp early 911's, and Lotus Elan's with 165bhp in a 600kg chassis, but the same rule applies. put too big a tyre on a rim designed to take a certain size, and the movement of the tyre on the rim will make the car feel worse.
Similarly, too big a wheel on a car designed for, say 15" wheels, and without any more mods to the suspension you fit a 17" wheel and a tyre two or three widths wider, the same thing happens.
For example, my first Up, a 75bhp High Up, came with 17" Polygon alloys and the factory sized tyres . Compared to my wifes High Up with 16" Alloys and taller, narrower tyres, it didn't feel right, the compliance of the tyre with it's lower aspect ratio adversley affected the ride, & it felt "over-tyred".
When we sold her Up, we put the Polygons on her car and kept the Triangle 16" on mine.
It is of course, personal preference, but in my generation at least, it's thought of as a well known mistake to make.
 

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Discussion Starter #16
Yes, I don't doubt the unsprung weight is pain on average and poor roads. It is, partially I had to accept this. This is why I am running on lower pressure. I have to. Factory 195/40 tyre is hard piece. It's more like a lipstick layer. There is a chance I will find 15x6.5 wheels that I like, but they have to make that "little hooligan" effect - visually. They should be black and light. Then I will be able to make real life comparsion.
 

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You will use more fuel trying to push bigger wheels and more rubber, fact, as the engine has to work harder to turn the weight and even more so at speed.

Try this experiment at home; Get 2 bike wheels, one mountain bike and one race bike of similar size. Now grab the axle and spin the wheel and then try and replicate the act of turning. You WILL find the lighter race wheel changes direction far easier with less force.
Now apply that to your car and that's what you're asking it to do every time you turn, accelerate and brake. The car has to use more energy to do the same process when you have the bigger heavier wheels and tyres on.

This multiplies more with smaller powered and light cars than bigger, heavier more powerful cars, the effect is way more noticable. Do this to an RS6 for instance and i doubt you'd notice.
Also as a side note: more rubber on the floor doesn't necessarily equal more grip and control. There is such a thing as over-tyred where the car just doesn't really respond and just ploughs through with no finesses. Put fat tyres on the front of a classic beetle for instance and you'll get what i mean; someone did that to my partner's beetle at some point and it made the steering dead and heavy and as a bonus wore out the steering box. i swapped them back from a 185 to 145 as it should be and it's perfect again, feels responsive and controlled.
 

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Discussion Starter #18 (Edited)
You will use more fuel trying to push bigger wheels and more rubber, fact, as the engine has to work harder to turn the weight and even more so at speed.

Try this experiment at home; Get 2 bike wheels, one mountain bike and one race bike of similar size. Now grab the axle and spin the wheel and then try and replicate the act of turning. You WILL find the lighter race wheel changes direction far easier with less force.
Now apply that to your car and that's what you're asking it to do every time you turn, accelerate and brake. The car has to use more energy to do the same process when you have the bigger heavier wheels and tyres on.

This multiplies more with smaller powered and light cars than bigger, heavier more powerful cars, the effect is way more noticable. Do this to an RS6 for instance and i doubt you'd notice.
Also as a side note: more rubber on the floor doesn't necessarily equal more grip and control. There is such a thing as over-tyred where the car just doesn't really respond and just ploughs through with no finesses. Put fat tyres on the front of a classic beetle for instance and you'll get what i mean; someone did that to my partner's beetle at some point and it made the steering dead and heavy and as a bonus wore out the steering box. i swapped them back from a 185 to 145 as it should be and it's perfect again, feels responsive and controlled.

Yes you will use more energy for accelerating-spinnig heavier wheel, but kinetic energy is staying there. in the wheel's mass rotating and you will reuse it later, unless you hit the brakes. If you are reusing it, fuel consumption is not changing almost at all. Slower accelerating with heavy wheels on 75hp car may be noticeable on 1st gear only. I believe so. On second gear accelerating total weight of the vehicle is more important. Much more important, as, as I have told before, wheel is not accelerating rapidly at all. And then at higher speed, over 60kph wind resistance is applying and wheel and car's mass acceleration value becomes even lower.


I don't think 205 is overtyred for the Up. I have empirical experience in this matter as I told.

You cannot calculate this just like that, because it;s too complicated. It's dependent on tyre construction and tarmac/surface type. And weather conditions also. You can check/measure this only in real life conditions.

I have fuel consumption results also. I didn't lie.



The fuel consumption is more affected by the type of rubber mixture than the width of the tire. This is due to the basic friction patterns that no one can remember from the basics of physics. In the friction pattern there is no surface considered, it is irrelevant. It may be a bit important, but for other reasons. Not so important. But ok, I know BMW made i3 on 175 tires. Of course it's a dead end and it won't last long. Science is not based on myths.


And fuel consumption differences equals energy loses. No differences = no bigger loses. No bigger energy loses = similar performance.
 

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Discussion Starter #19 (Edited)
Below I argue that the difference in accelerating wheels is very small.



I’ve treated car wheels as flywheels for this calculation to make things easier.

Car no 1 has 14kg weighting wheel
Car no 2 has 18kg weighting wheel
Car no 1 weighs 1000kgs
Car no 2 weighs 1016kgs (because of heavier wheels)

The car’s speed is 50kph
Wheel diameter is 600mm
This makes 442RPM wheel’s speed
14kg wheel has 675 joules of energy at 50kph
18kg wheel has 867 joules of energy at 50kph

1000kg weight car moving 50kph speed has 96450 joules of energy
1016kg weight car moving 50kph speed has 97994 joules of energy


675 joules * 4wheels + 96450 joules = 99150 joules
867 joules * 4wheels + 97994 joules = 101462 joules


The calculated energy is equal to the energy needed to accelerate the cars. Friction or air resistance is not included, but they would still reduce the result.


99150 vs 101462 joules


This is 2,3% difference ( only one third of this 2,3% is caused by wheels and 2/3 is caused by 16kgs heavier car)
 

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Just want to add here that Piotr's setup isn't really extreme by any standards. He has a half inch wider wheel and he has up-sized his tyres by one step over the stock GTI. Just from a theoretical look at the numbers, all he's really done is fill out his wheel wells by about 14mm via a higher aspect ratio tyre, and I can imagine that if anyone bolted on a set of stock GTI Oswalds on the stock 195/40 Goodyear Eco's and then did a back to back with Piotr's setup, they wouldn't be able to tell any real difference. If anything, it would probably feel marginally more compfortable to drive due to the taller sidewalls.

Piotr doesn't seem to be a racer, and isn't going for max track day performance. Aesthetics are by definition subjective. Personally I feel that 17x7 ET35 with a 35-40mm drop is perfect aesthetically (though I would use 195/40 rubber) but that is IMHO.

I feel that the technical engineering discussion is a bit over the top for this thread, actually - now, if he was trying to squeeze on 19x8's on 205/30 rubber, then we'd probably have something to talk about with driving characteristics.

Piotr - I don't think you need to justify your wheel and tyre choice with a technical argument. You haven't changed the driving dynamics of your car in any truly meaningful way, and you like the resulting look. You don't have to prove anything to anyone. :) I like it, as it is an interesting choice.

I myself am going with 16x7 ET35 JR18 wheels in bronze on 205/45 R16 tyres on my white 5dr GTI, which keeps me within stock parameters for wheel and tyre diameter and circumference. Will also be lowered on H&R springs. Take delivery in 3 weeks, so am looking forward to comparing the final product with your setup.
 
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