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View Full Version : Racing - 17s vs. 16s



CCR#5
09-21-2015, 11:21 AM
For you guys whom have tracked both what were your opinions/feels. 17s give me better options for slicks and wider contact patch options, the negative being the higher COG which is a b&%*$ with these top heavy cars and curbs at speed. This is a track ONLY car(roadcourse no autox). The reason for the change/question is I finally have the car dialed in for 16s, but I'm running into cornering issues(opportunity) where I need to figure out a way to increase grip and/or tire contact patch size to get me a little more speed in/during/out of corners. I know I could push it a little harder if I had a little more grip. 17s are the natural solution as I can get a better patch size and the better availability of slicks and sticky DOT sizes, but the COG issue keeps me up at night. I've convinced myself that the increased corner grip and cog combination may open up a whole nother box of problems with stability. I love the way the car currently performs with 16s, sans the fact the car needs more grip in the corners. With low HP I need to carry as much speed as possible through the corners. Just need to see who has pushed the limits of grip vs. stability with the different rim sizes. Lowering the car further on 17s to get the cog back down isn't an options without some serious fender modifications.

Sizes for specifics:

205/45/16s
215/40/17s

BigDaddySRT
09-21-2015, 11:36 AM
I'll be modifying the Front Fenders as needed to get the 225/45R17 A7's to fit.
I am running Eibach Sportlines, so only the front clearances cause me any concern.

CCR#5
09-21-2015, 01:16 PM
yea I have the a7s in that size and the front is what kills me. If you want a spare set I'll make you a great deal! still have the stickers on em.

BigDaddySRT
09-21-2015, 08:11 PM
yea I have the a7s in that size and the front is what kills me. If you want a spare set I'll make you a great deal! still have the stickers on em.

How much am I going to have to roll out the Fenders?

Is that something you didn't want to do? Did you have the Fender Liners installed?

jguerdat
09-22-2015, 07:27 AM
What about going to 15 inchers? Could you get shorter but wider tires with less chance for fender contact?

CCR#5
09-22-2015, 07:57 AM
biggy - certainly going to have to roll the fenders, there is an inner metal lip that needs to be pounded up/flat as well. Liners will need to be modified and/or removed. The big rub, literally, will be the front fender liner/bumper tie-in area even with the side orange marker reflector. there is a screw there that holds together the upper and lower sections that is right in the path on turn in. When I get back in town this weekend I'll snap a pic of the rub damage from when I ran the slicks. depending on how soft your suspension is and if you street drive it you may also have some issues with the inside engine side wheel well area.

Megalomaniacal
09-22-2015, 10:11 AM
go for the wheel size that has a cheaper market and greater availability for tires, so a set of fresh R compounds doesn't break the bank. I believe 16's are less expensive than 17s


compound > contact patch imo

SweetSandMan
09-22-2015, 10:20 AM
225/45 16 here...you MAY experience some rubbing but that will all be dependent on your suspension setup. I'm running ST Coilovers and I occasionally rub in the front under heavy front load like hard sweeping corners and larger dips in the road. Don't have any issues with bumps, though. I think it's because these Coilovers are just too soft for this tire setup.

scrumby14
09-22-2015, 05:05 PM
I agree with Megalomaniacal. The 16's has a lot more tire options to choose from (a lot more sticker tires to choose from!). And plus they're at least 20 bucks cheaper.

Currently running Enkei's PF01s with 205/40R17. My car is setup quite stiff and it gets a bit peppy. So running 16s with taller sidewall w/ some sidewall flex tends to brings my car back in check.
Also I do feel the center of gravity is lower, you can chuck it into a turn and don't feel like sway bar being overworked from load lateral load transfer.

If you were to ask me to pick a set of wheels again, I would choose 16s over the 17s. Or even go w/ 15s. Definitely you will benefits and feel-able difference with Lighter wheels.

E Rossi
09-22-2015, 05:50 PM
I've been told that the 17's create more drag than the 16's, thus slower top speed due to aerodynamics.

This is from the Fiat 500 USA factory sight:
500 Abarth: 0.352 — with 16-in. wheels
500 Abarth: 0.365 — with 17-in. wheels
500c Abarth: 0.352 — with 16-in. wheels
500c Abarth: 0.365 — with 17-in. wheels

http://www.fiat500usa.com/2014/06/2015-fiat-500-abarth-specifications.html

stealthy1ss
09-22-2015, 10:13 PM
My favorite track setup that I have had on my car is the stock 16's with 205/45 Toyo R1R's with corner balanced KW V1 coils. The front camber was somewhere around -2.3 with 0 toe and my lap times at Road America were around 3:00 flat. I will tell you that it is hard to get good clearance with 17's and coil overs when you run a bigger tire. I sucked in a fender with a 215/40/17 on my coils.

CCR#5
09-23-2015, 08:55 AM
rossi - you are correct, though it has a lot to do with increasing the drag disproportionally to the corner grip increase. I was always taught to shoot for a square contact patch and as you get longer(rectangle) you increase drag at a faster rate than corner grip.

Ended up going with some 205/45/16s for a test. Starting with some Federal 595 RSRs since they have great grip and are cheap enough to try out and if I don't like the setup its not a big loss. Im thinking the 215s or 225s would have too much wiggle.

I actually took camber out this time round. Was running right at -2 on the nose for camber and didn't like the feel at all. Adding in -.5 from factory this time round and see if that puts the car back how I like it. I set tow in a bit and I thought it really kept the car aimed more to my liking. I'm still playing around with the rear as I'm convinced there is a better setup than the ones I've tried back there thus far. Then again I'm also not very hot on the 28mm bar I have back there so I may step down to a 26 and redo all my past setup tries.

BigDaddySRT
09-23-2015, 05:45 PM
biggy - certainly going to have to roll the fenders, there is an inner metal lip that needs to be pounded up/flat as well. Liners will need to be modified and/or removed. The big rub, literally, will be the front fender liner/bumper tie-in area even with the side orange marker reflector. there is a screw there that holds together the upper and lower sections that is right in the path on turn in. When I get back in town this weekend I'll snap a pic of the rub damage from when I ran the slicks. depending on how soft your suspension is and if you street drive it you may also have some issues with the inside engine side wheel well area.

How much negative camber were you running?

I had the Hoosiers mounted on my Forged Wheels... Advans will now become street tires.
I barely clear the suspension, might need to add spacers and longer wheel bolts.

This Friday will be working in the garage to get these things to fit.

Anyone in North Texas have a Fender Roller I can borrow or buy for a discounted rate?

CCR#5
09-24-2015, 08:44 AM
the hoosiers were mounted on a set of oz legennda racing rims so I was a bit further out than stock b/s. We were running right on factory specs with the slicks. With stock rims I'd think you'd need atleast a 10mm spacer if you're running -2 camber to clear the tower. I'm not sure there is enough to work with to roll the fenders for 225 slicks. If I were going that route again I would cut about .25" off the wheel opening starting at 2 o'clock and as I went counter clockwise I would taper that out to .75" right above the side marker. Then completely yank the front half of the wheel well liner out and cut out the rear "bump" part of the liner. BUUUT keep in mind I'm sitting very very low on KW V3s.

You know you could always use a metal baseball bat to roll them. Does a decent job, just a pita and you have to go slow. Only other thing I will throw out there is the car gets veeeeeery light in the rear under hard braking with the slicks. You almost NEED a little bit of 'skidding' to keep the rear end on the ground.

BigDaddySRT
09-26-2015, 08:56 AM
the hoosiers were mounted on a set of oz legennda racing rims so I was a bit further out than stock b/s. We were running right on factory specs with the slicks. With stock rims I'd think you'd need atleast a 10mm spacer if you're running -2 camber to clear the tower. I'm not sure there is enough to work with to roll the fenders for 225 slicks. If I were going that route again I would cut about .25" off the wheel opening starting at 2 o'clock and as I went counter clockwise I would taper that out to .75" right above the side marker. Then completely yank the front half of the wheel well liner out and cut out the rear "bump" part of the liner. BUUUT keep in mind I'm sitting very very low on KW V3s.

You know you could always use a metal baseball bat to roll them. Does a decent job, just a pita and you have to go slow. Only other thing I will throw out there is the car gets veeeeeery light in the rear under hard braking with the slicks. You almost NEED a little bit of 'skidding' to keep the rear end on the ground.

Mission accomplished!!! I'll post pictures soon. This weekend is Anniversary weekend for me so I knocked out the ABARTH yesterday.

CCR#5
10-07-2015, 07:49 PM
definitely let me see how it turned out. I still have the slicks sitting in the corner.

Abnormalradio13
10-14-2015, 04:58 AM
I'm currently running the RE-71R tires 215/45/17 and although they have amazing grip, it doesn't help when I take a high speed corner and have to worry about two wheeling half way through (done it twice). I thought about running 15s but I think 16s may be better but then again who knows.

doverosx
10-14-2015, 07:22 AM
the hoosiers were mounted on a set of oz legennda racing rims so I was a bit further out than stock b/s. We were running right on factory specs with the slicks. With stock rims I'd think you'd need atleast a 10mm spacer if you're running -2 camber to clear the tower. I'm not sure there is enough to work with to roll the fenders for 225 slicks. If I were going that route again I would cut about .25" off the wheel opening starting at 2 o'clock and as I went counter clockwise I would taper that out to .75" right above the side marker. Then completely yank the front half of the wheel well liner out and cut out the rear "bump" part of the liner. BUUUT keep in mind I'm sitting very very low on KW V3s.

You know you could always use a metal baseball bat to roll them. Does a decent job, just a pita and you have to go slow. Only other thing I will throw out there is the car gets veeeeeery light in the rear under hard braking with the slicks. You almost NEED a little bit of 'skidding' to keep the rear end on the ground.

I lift my rear wheels under braking with RS3s.

Abnormalradio13
10-15-2015, 12:18 AM
I think at the end of the day it'll have to come down to tire selection. Next year I plan to run both 16s and 17s because of the selections that's available

CCR#5
10-15-2015, 03:04 PM
ended up getting a set of Federal 595 RSRs on the 16s for now. I'm very impressed with how sticky they are, the price is great, and they came very highly recommended from a few of my pro friends. With these cars there is such a thing as too much tire/grip so I think the trick is going to be finding that perfect mix of spring rate, weight, and tire grip. These cars are a lot more sensitive to driving technique than one would guess. Really forces you to drive a smooth line and pay close attention to the weight transfer/transition.

Michael T
11-01-2015, 07:37 PM
ended up getting a set of Federal 595 RSRs on the 16s for now. I'm very impressed with how sticky they are, the price is great, and they came very highly recommended from a few of my pro friends. With these cars there is such a thing as too much tire/grip so I think the trick is going to be finding that perfect mix of spring rate, weight, and tire grip. These cars are a lot more sensitive to driving technique than one would guess. Really forces you to drive a smooth line and pay close attention to the weight transfer/transition.

What size?

CCR#5
11-03-2015, 02:51 PM
205/45/16 the full out track tires are the RSRs... they also offer a SS and regular 595 version. Only thing you need to do is bend the ebrake bracket up against the control arm for clearance. Its a little tight upfront with the shock tower, so may want to run 5/10mm spacers if you need the piece of mind. I could get my hand between the tire an the tower so not required, but certainly closer than some people may be comfortable with.