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Re: CONS of putting 17" wheels on 86 16v Scirocco? (Road America)

If you plan on putting the car on the track, i.e. "road course", the 17s will give you slower times than a 16 or better yet a 15. If you are going to 17s "just to get bigger/better brakes", at 2200-2300 lbs., you don't need that much to stop a Scirocco. I'd stick with a lightweight 16, for looks, and you could go with a Brembo, or Willwood calipers, w/race pads for track days. Willwoods or the 2 piston Audi TT calipers would fit under the 15s. with the Stainless Steel lines, you'll have plenty of stopping power, and a better handling/accelerating car with the smaller wheel. My $.02.
 

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Re: CONS of putting 17" wheels on 86 16v Scirocco? (colnago)

In my opinion, it's not about the weight of the car but how much power you add to the car combined with the weight, i track my yellow car with 17's and I use to boil my brakes, but then again i am really hard on my car
I did up size my brakes to 12.2 wilwood w/ willwood 4 pistons callipers, and dot 5 fluid, no problems now, my wheels also weigh as much as the average set of 16's 18 lbs, now to answer the question which should have been asked in the forum section
the 17's most likely will hit the fender lips so you'll have to roll them I had to lift my car up from its old ride height with coilovers because it was too low, and use wheel spacers on the rear, but that was my doing because it handled a little better
 

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Re: CONS of putting 17" wheels on 86 16v Scirocco? (vwdohc993)

Quote, originally posted by vwdohc993 »
In my opinion, it's not about the weight of the car but how much power you add to the car combined with the weight, i track my yellow car with 17's and I use to boil my brakes, but then again i am really hard on my car
I did up size my brakes to 12.2 wilwood w/ willwood 4 pistons callipers, and dot 5 fluid, no problems now, my wheels also weigh as much as the average set of 16's 18 lbs, now to answer the question which should have been asked in the forum section
the 17's most likely will hit the fender lips so you'll have to roll them I had to lift my car up from its old ride height with coilovers because it was too low, and use wheel spacers on the rear, but that was my doing because it handled a little better

I just think that going to 17s, "just to get bigger brakes", isn't worth what you would lose in "handling". "Appropriate" brake calipers can be installed with a smaller wheel. And yes, Mass x Velocity = Power. More weight at a given speed will require more "stopping power". So my "G60 brakes" will stop a Scirocco "MUCH" better than my heavier, and probably more powerful, 1.9l G60. It would have 400-500 less pounds to stop. I'd much rather try to stop Allen Iverson from driving down the middle than Shaq.
But for better braking, its all about proper (race) pads, lines, fluid, and multi-piston calipers.
I think European Car or Eurotuner just did an article on a Jetta using different sizes, (15,16, and 17 inch wheels) of the same wheel (BBS RX) and tire combination. The 17s posted the slowest lap times, 15s were the fastest, by over 2 sec. The 16s were closer to the 15s on lap time, but the 16s and their corresponding sidewall ratio, proved to be the more consistent "handler". That's something to consider if you are "competing".
 

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Like everyone said, get light wheels and tires. To break even on inertia, you'll need to lose a few pounds in the upgrade because the rim is located further from the wheel center, so you gain inertia even if you keep the weight the same.
Also, if you currently tune your handling by making air pressure adjustments, you'll need to get your suspension sorted out. Air pressure adjustments (or differences between front and rear pressures) basically adjust the springiness of the sidewalls. When you shorten the sidewalls by increasing the wheel size, the effectiveness of air pressure adjustments for tuning is seriously reduced.
Oh, and for brake upgrades, think better pads. Bigger brakes are usually heavier brakes and hurt accelleration (more inertia) and handling (more unsprung weight). Better pads will increase brake forces and reduce fade without any of the negatives of bigger parts. With the right pads, the 10.1" fronts and 8.9" rears are probably good for any street or track driving so long as you keep the weight below 2700 pounds and the speed below about 140mph. If you weigh less, you can go slighly faster before you need to worry. The main thing is selecting pads that are appropriate to how you drive and where you drive.


Modified by Racer_X at 5:13 AM 5-14-2003
 

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Discussion Starter · #10 ·
Re: CONS of putting 17" wheels on 86 16v Scirocco? (Road America)

Ok, yea, I goofed being in the wrong section. Guess I was too caught up in reading ads. Ok, let me explain here.
1. I'm not worried about my shop scratching my wheels. He's got the equipment to do it right.
2. I'm not buying bigger wheels to get bigger brakes, but bigger brakes because the stock brakes will look silly.
3. Handling? I'm really confused here. I think people are confusing handling with ride quality. I'm running larger wheels and tires (both diameter and width) on both of my Porsche's than the factory ever intended. Wasn't easy, but I was able to get them to fit. The result? Instant increase in handling. Less sidewall means less tire roll = better handling. I have yet to read otherwise in any racing document. Please show me where this has been tested. Granted, my 928 especially, rides like a dump truck with the larger wheels, but that is the price I was willing to pay. I guess since a couple of you brought it up, and I've met other VW people with the same opinion, I'm curious where this belief that a taller sidewall will result in better handling. Ok, I will admit that most larger wheels for these cars are very heavy and most people don't spend the $$$ to get light wheels.
What I was looking for I did get so thank you guys (gals) for the input. Rubbing, fender clearance, etc..... I'm researching offsets as well to get the best fit. I plan on buying a set of Fiske wheels for my Scirocco. The dark gray 5-spokes. They will make any size/offset and are extremely light. If you haven’t checked out their wheels yet, you should they are awesome!!
Currently I'm running at 35 series on the 928 and 40 series on the 944. The Scirocco with 17's will be 35's. Granted, the 928 wheels are much wider then the Scirocco could ever hold, possibly giving a slightly softer ride then the Rocco will.
If I go with 17's it will be with the purpose of making it 75% of the time a track car. The other 25% shows and club functions.
Thanks for the input!!
 

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Re: CONS of putting 17" wheels on 86 16v Scirocco? (Road America)

Ugh, PLEASE don't do it.
The whole "bigger is better" wheel nonsense (and it IS nonsense) is a Mk4 thing, and IMHO nothing bigger than 15's (which is a +1 application over the original 14's) should EVER grace any A1-chassis VW.. not only for all the tangible reasons stated above, but also because they just look plain silly on a tiny A1. Resist the temptation! Find a nice, lightweight 15" wheel - something period-correct (BBS, ATS, Ronal, etc.) and be happy.
 

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Re: CONS of putting 17" wheels on 86 16v Scirocco? (Road America)

Quote, originally posted by Road America »
The Scirocco with 17's will be 35's.

35s? 225/35/17 is the only size I know of. Good luck fitting those suckers! Or did you have another size in mind? I would add to the discussion on the CONS of adding 17s but I think everything has been mentioned, cept for maybe the fact that your wheel bearings wont last as long (its that way for me at least with my 17s).
BTW, welcome to the Tex! The forums where half the crackpots dont even bother to answer your question or help you out in any way, but instead they tell you what they would do instead.
 

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Taken from vividracing.com
Now, it has long been believed that bigger is better. In the case of wheels and tires, this only applies to cosmetics. You see, the added weight of a wider tire actually makes the vehicles engine have to work much harder to accelerate. Likewise, as you go to a larger diameter wheel, the weight of the wheel is moved further from the center, and again is much harder to accelerate. In a recent issue of Sport Compact car, they did some tests on the effects of different wheel diameters on acceleration, and track times. They tested 16, 17 and 18-inch wheels, on the same car. They also tested the effect of adding 200 pounds of dead weight to the interior of the vehicle. The difference in quarter mile times and road-course times, as the wheel size was increased, was fairly close to the effect of adding 200 pounds of weight to the car.
The larger diameter wheels, with tires of the same circumference slowed the car down every time. One other consideration when picking wheels and tires is the contact patch. For all intensive purposes, your car has a static mass (if you have a WRX, it's about 3100 lbs). Given a set tire pressure, no matter the tire size (within reason), you will have a set contact patch area. As you drive your car hard into a corner, the tire will start to roll over onto the sidewall. The contact patch changes shape. If 20% of the tire is no longer touching the road, and you have a large round contact patch, then you loose perhaps 25% to 30% of your rubber on the road. If you chose wider tires, and have a longer narrow contact patch, then the 20% of the tire no longer touching the road may only represent a loss of 10-15% of the contact area. This is why people 'should' run wider tires. Anyways, if you want to upgrade your car with the best possible package, choose a high quality tire. Yokohama, Nitto, BF Goodrich and Toyo make some excellent high performance models. If you currently have any sort of all-season on your car, and you want the biggest possible increase in cornering and braking ability, upgrade those tires. As for wheels, pick something that is cosmetically pleasing, but is light weight. Often you can tell the quality of a wheel by price. The incredibly lightweight Volk Racing TE37's are several hundred dollars a wheel, while your local garage may be able to source out an identically sized wheel for well under a hundred dollars. You typically get what you pay for. Don't let your desire for 'bigger is better' get the better of you. Choose quality over quantity!
 

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Re: CONS of putting 17" wheels on 86 16v Scirocco? (PA 16v)

Really, you'll be fastest on the track with 14"s...with a brake pad upgrade to stock calipers, new SOLID rotors and SS lines; that's all you really need to have the car at its best....that and a course in tracking a car. I did the Skip Barber school and dropped my lap times at Lime Rock by 3 secs plus with no mods to the car. Tracking a car successfully is 70% driver and 30% car.
17"s do look sharp , I'll agree, but you'll probably be embarassed by being the slowest car out there with them on a 130 hp car. just my 2 centivos...
 

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Re: CONS of putting 17" wheels on 86 16v Scirocco? (Road America)

Quote, originally posted by Road America »
Ok, yea, I goofed being in the wrong section. Guess I was too caught up in reading ads. Ok, let me explain here.
1. I'm not worried about my shop scratching my wheels. He's got the equipment to do it right.
2. I'm not buying bigger wheels to get bigger brakes, but bigger brakes because the stock brakes will look silly.
3. Handling? I'm really confused here.

Perhaps.
Quote, originally posted by Road America »
I think people are confusing handling with ride quality.

Maybe you are confusing absolute lateral grip and sidewall stiffness with real world handling. As soon as you find a bump on the road in the middle of a corner, they aren't the same thing. In a bumpy turn, some compliance in the sidewalls is a very good thing. It allows the tire to soak up some of the bumps entirely, and to absorb a significant portion of larger bumps, too. That keeps the movement of the unsprung weight to a minimum and keeps the tread in contact with the road better.
With stiffer, shorter sidewalls, more of the energy of the bump is transfered to the wheel and unsprung weight of the suspension (and brakes). If you increase the spring rates and stiffen the dampers (shocks) to handle the added spring, you get more roll stiffness (and often more understeer in our VW's). You also get a more significant temporary spike in the loading of the tire when you hit the bump (and more lateral slide from the overload, just like from a more roll stiffness). So you get less lateral force on the rising side of the bump. Going to a softer spring and shock package to increase compliance will keep the load lower on the rising face of the bump, but it will fail to control the unsprung weight once you cross over the top of the bump, and the tire will unload on the back side of the bump and lose some lateral grip. Basically spring and shock adjustments will allow you to choose which side of the bump you lose the most grip on, but the only way to get more grip on both sides of the bump is to have more compliance in the tires.
Back in 1994 or 1995, I ran an improved touring 1986 Golf GTI. Just for the heck of it, I took several different wheels to a Porsche club high performance school (I was an instructor for the school). I ran 13" wheels, 14" wheels and 15" wheels on my car with basically the same tires (all the same make and model of tire, 205/60-13, 205/55-14 and 205/50-15 sizes). The tires were DOT race compound tires. My Golf GTI had the best lap times with 14" wheels. It had the highest speed at the end of the straights with the 13" tires, but it was really "squishy" in the corners with the taller sidewalls. It felt a lot like an A1 car without a lower stress bar. Perhaps if I had taken a few more sessions and made some tire pressure adjustments, I could have worked around that a little more, but I didn't try. It had the slowest speed at the end of the straight with the 15" wheels and tires.
A friend who was also at that event had a set of 16" wheels that fit my car as well. Those wheels had racing slicks on them. I tried those wheels and tires, too, and they were even slower on the straights, and the lap times with those 16" wheels and slicks were only slightly faster than the 15" wheels, and still not as fast as the 14" wheels.
With the bigger wheels on the car (the 15" and 16" wheels), it felt very skittish through the bumpier turns on this track (there were two long sweepers that had some rough spots in the middle of the turns). Through most of the other smooth turns, the shorter sidewall resulted in a sharper feel to the car, and this helped speed through the smooth corners slightly. Still, it wasn't enough to make up for the losses on the straights and the bumpy turns.
IIRC (and it's been a long time, I could probably dig up my notebook entries on this if you really wanted the exact times), the 13" wheels (VW Tarantula wheels) were about 1.5 seconds per lap slower than the 14" wheels (VW Snowflakes), and the 15" wheels (Ronal turbos) were about 2 seconds slower. The 16" wheels with the racing slicks were about 1 second slower than the 14" wheels. That's from 7-8 year old (possibly faulty) memory, though, so take it with a small grain of salt. I'm certain that the fastest times came with the 14" wheels, though.
 

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Discussion Starter · #17 ·
Re: CONS of putting 17" wheels on 86 16v Scirocco? (Racer_X)

Interesting.
I see some good points and see holes in some of the ideas but overall a lot to think about and research.
In looking around the web, other various sites with forums, I've looked for similar topics. This is the only one I started on the issue.
My current conclusion is the negative effects of 16" or larger wheels on a Scirocco has more to do with the Scirocco itself than the idea of larger wheels in general. Any upgrade is like that. Just because something makes a 911 Turbo faster doesn't mean that will also make a Camero faster etc....
Let’s take Porsche's. 15" phone dials on a 250hp 944 turbo is not better than 17" Fiske's. The reason why I keep using Fiske as an example because they build one of the best wheels on the planet. I use them as an example to eliminate out of the equation the possibility of wrong offset, fitment etc....What I'm getting at here is wheel, suspension, hell, any chassis upgrade can be overdone for any car.
The Scirocco is so narrow, light and let’s face it, 20+ year chassis design is really what we are talking about and the effects of much stiffer corners. Take a Dodge Viper, plop in the stiffest sidewall tire on a 15" wheel, it won't handle as good. Yea yea, I know 15's won't fit over the brakes but work with me here, ok?
This will ruffle some feathers but it is not meant to. Driver skill is also a big part of this as somebody else mentioned. If you drive your VW for a couple of years with stock wheels. Then slap on a set of 16" wheels with a really good tire, you won't instantly know how to get most out of the new setup. Especially when you are so used to how it was before. So if you drive the same way with a different setup, yea you'll be slower. That's just plain common sense. Again, I'm not saying that is the only factor here, just one of many.
Ok, I'm done with the wheels discussion. I'm 99% sure I'll be getting 16's at this point. One comment from above I can't even begin to understand though is:
"Really, you'll be fastest on the track with 14"s...with a brake pad upgrade to stock calipers, new SOLID rotors and SS lines"
Solid rotors? Do you mean unvented? Holy cow. Nobody will EVER convince me that keeping your brakes cool is bad. If you mean non-cross drilled I agree. Slotted is the way to go. The effects of slotted was instant at Road America on my 944S. Just curious what you meant by Solid Rotors.
 

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Re: CONS of putting 17" wheels on 86 16v Scirocco? (Road America)

Let’s take Porsche's. 15" phone dials on a 250hp 944 turbo is not better than 17" Fiske's. The reason why I keep using Fiske as an example because they build one of the best wheels on the planet.
Hey I resemble that remark
Fikse FM10's baby



Modified by vwdohc993 at 2:03 AM 5-17-2003
 
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