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jguerdat
04-29-2013, 08:45 AM
Is there any way to reasonably use 15" wheels on an Abarth? It would seem that some spacers might be needed - how much offset would be needed as well as what offset on the wheels themselves?

The purpose would be to use BFG Rivals in sizes that could actually be advantageous for autocross. The 16" and 17" sizes are ludicrous. Next year's SCCA street class rules allow +/-1" diameter changes so 15s would be possible if they can fit without big changes.

2Cool
04-29-2013, 08:58 AM
The Monza 6.5" wide wheels bolt up without spacers. You lose a bit of width, but man do I love how they look. 17"s on our cars make the brakes look tiny.

JackandSue
04-29-2013, 09:42 AM
I too am interested in this subject as there seems to be a much better collection of fires in the 15" range. It seems the largest tire for a 6.5 rim is the 205, 7.5 fits a 225
. Would like to hear more on this from our racers out there.

JackandSue
04-29-2013, 09:46 AM
alot
Is there any way to reasonably use 15" wheels on an Abarth? It would seem that some spacers might be needed - how much offset would be needed as well as what offset on the wheels themselves?

The purpose would be to use BFG Rivals in sizes that could actually be advantageous for autocross. The 16" and 17" sizes are ludicrous. Next year's SCCA street class rules allow +/-1" diameter changes so 15s would be possible if they can fit without big changes.

I've found a nice autox tire it's a Federal 595racer. 140 treadware its used in Japan a lot and was the sponcer tire for the Lotus Challenge. I went with the 205/45/16.

Abarth Five O
04-29-2013, 12:59 PM
Depending on the design, offset, etc. you might have clearance issues over the brake calipers and rear sway bar. The best way to figure that out is to do a test fitment.

2Cool
04-29-2013, 01:36 PM
The Federal tires are as low as $76 in 205/50-15, though I would worry about daily driving them as they state "for competition use only".
Falken 615Ks, Kumho XS, and even Bridgestone RE-11A's are all in the range of $100 to $115 each in that size. So amazing performance for cheap, plus a cool retro appearance.

jguerdat
04-29-2013, 04:25 PM
I was kinda hoping a sponsor might have something to say about this. With no ability to go someplace and test fit wheels, it'd be a crapshoot. Someone who has already done this or has access to a selection of wheels would have invaluable info.

shagghie
04-29-2013, 04:36 PM
I was kinda hoping a sponsor might have something to say about this. With no ability to go someplace and test fit wheels, it'd be a crapshoot. Someone who has already done this or has access to a selection of wheels would have invaluable info.

This ^^^

The Federal is a good looking tire:
http://im9.cz/iR/importprodukt-orig/647/64715587d3053444f05a657710aae3c1.jpg

Are you running these now Sue? Care to compare to Direzza's, AD08's or the new BFG Rivals?

I'm also thinking about 15" as well....but like the OP, I have no way to test fit a pair. I was looking at some of the racing wheels in a summit racing catalog, for example.
They have some wider 15" wheels, some of which are DOT legal, and not terribly ugly... not sure how they'd hold up for a DD though...which is what I was wondering.

stealthy1ss
04-29-2013, 05:10 PM
Here is a 15x8 +20.

http://i202.photobucket.com/albums/aa263/stealthy1ss/photobucket-84736-1366323189955_zps6af76184.jpg (http://s202.photobucket.com/user/stealthy1ss/media/photobucket-84736-1366323189955_zps6af76184.jpg.html)

Without rolling, pulling, and stretching the fenders I believe that a 15x7 or 15x7.5 +30 wheel will work perfectly. There are no issues with clearing the brakes.

Seafarer61
04-29-2013, 05:45 PM
This should help...
http://www.rimsntires.com/specs.jsp

jguerdat
04-30-2013, 09:40 AM
Here is a 15x8 +20.

http://i202.photobucket.com/albums/aa263/stealthy1ss/photobucket-84736-1366323189955_zps6af76184.jpg (http://s202.photobucket.com/user/stealthy1ss/media/photobucket-84736-1366323189955_zps6af76184.jpg.html)

Without rolling, pulling, and stretching the fenders I believe that a 15x7 or 15x7.5 +30 wheel will work perfectly. There are no issues with clearing the brakes.

Leave the car at stock height with those suckers... ;)

I thought the whole issue with the Abarth was bigger brakes, etc. that precluded using at least the OEM spec 15s. Maybe they're not +30 offset?

shagghie
05-02-2013, 02:26 PM
What would be a good target offset for 15 x 8's on a lowered suspension set up? Would a +35 work, and not rub under auto-x conditions?

Deefourtay
05-02-2013, 03:05 PM
I use to run Federal 595 in my drifter days, they are hands down still my only liked "budget tire". Great value, and the grip is amazing! Stiff sidewalls, very predictable.

Abarth Five O
05-02-2013, 03:05 PM
Shaggie, I initially looked into 15s for the Abarth, but most will not clear the OEM brake calipers and/or rear sway bar. 16s were recommended by R/R to safely clear the stock setup, but if you wanted to go with bigger brake calipers later on, then I would go with 17s to save some $$.

shagghie
05-02-2013, 04:35 PM
Shaggie, I initially looked into 15s for the Abarth, but most will not clear the OEM brake calipers and/or rear sway bar. 16s were recommended by R/R to safely clear the stock setup, but if you wanted to go with bigger brake calipers later on, then I would go with 17s to save some $$.

So the wheels I'm looking at can handle up to 11.5" rotors no problem. I think ours are 11.1" if I recall, so tight fit, but do-able. Not sure about the sway bar though. is it the wheels to worry about there or the tire during deflection, or? Now you have me worried...

shagghie
05-02-2013, 05:22 PM
Not sure if I'm using this tool right, but if so, I think 15 x 7.5" is about as wide as we can go with a +36 offset wheel.
Using our stock 17" wheel at +35 offset and 7", and plugging in the new wheel at 8" and +36offset, we get:


Inner Clearance: (the inside of the wheel to the strut housing): 14mm
Outer Position: (position of the outside edge of the wheel): 12mm

When we reduce the width of the new wheel to 7.5" (vice 8"), we get:

Inner Clearance: (the inside of the wheel to the strut housing): 7mm
Outer Position: (position of the outside edge of the wheel): 5mm

I think 5mm is fine considering I'm running 10mmF/15mmR spacers now on stock 17's, but 12mm would be pushing it, although I know the Italian Abarth forums swear by 12mm spacers F&R. At that point probably a slightly stretched tire would be needed?

But it's the INTERNAL clearance I'm mostly worried about with an 8" tire..12mm seems like a lot to not hit either the Torsion Bar or other suspension components.


Am I like way off in left field, or is the above making general sense? Sorry, I'm new to wheel fitment, so trying to learn best I can, and I really want to pull the trigger on these wheels and go as wide as possible.

Tool: http://www.1010tires.com/Tools/Wheel-Offset-Calculator

stealthy1ss
05-02-2013, 06:19 PM
With the stock struts you will run into problems with fitting wide wheels because of the lack of camber adjustment and the part of the strut where the bottom of the spring sits. Coilovers will solve those issues but are quite expensive. I can tell you that the 15" XXR 530's will clear the rear sway bar mount and the front calipers.

shagghie
05-02-2013, 06:34 PM
With the stock struts you will run into problems with fitting wide wheels because of the lack of camber adjustment and the part of the strut where the bottom of the spring sits. Coilovers will solve those issues but are quite expensive. I can tell you that the 15" XXR 530's will clear the rear sway bar mount and the front calipers.

I'm on Madness Coilovers for now until the Fortunes are ready. They've done OK for me so far this auto-cross season, but I have camber set at the stock specs right now. Do you think i'll need to run neg camber in the rear with 15 x 7.5' for sake of fitment (handling aside for a moment)?

Deefourtay
05-02-2013, 06:49 PM
I've seen the BBS CS4 fit onto our cars without issues.. And the specs for those is 17x7.5 +30! The 15 inch ones should fit fine as long as it clears the fenders and brakes as well.

Something that tucks nicely under the fender without stretching the tires is ideal.

Wider wheels = less clearance on the brake/strut side, that's where you need Negative Camber to compensate for that.

General:

- Camber = Popping out of the fender side

+ Camber = Closer to the Brake/Strut Assembly side

Abarth Five O
05-02-2013, 07:34 PM
The rear sway bar mounts could present clearance issues. Your safest bet is to get a test fitment to make sure it will clear the 15s.

Deefourtay
05-02-2013, 07:36 PM
The rear sway bar mounts could present clearance issues. Your safest bet is to get a test fitment to make sure it will clear the 15s.

For sure, a reputable Tuner Tire/Wheel Shop should be able to help you test fit different sizes of wheels so you can make sure that it has the right clearance.

stealthy1ss
05-02-2013, 08:04 PM
Some places will let you buy just 1 wheel to test fit and if it doesn't fit they will let you return it as long as you don't mount a tire on it. I know that NLMotoring will let you do that.