Downsizing to 17s

[tian647]

I have decided I hate how clumsy my ZHP feels on the heavy OE wheels, so I mounted snow tires on my Styling 135s and am now casually shopping for a set of 17" wheels to run come spring as they are far lighter, cheaper and I can buy them square so I can rotate my tires to extend their useful life.

I'm eying up Kosei K-1s in 17x8.5" (only 15.4 lbs) but wondering if 245/45s will fit all the way around without rub/clearance issues up front.

How wide of tires are folks running up front on stock suspension? I'm guessing 255s are right out, no?

Thanks all!


Christian

[LivesNearCostco]

The Koseis are popular and were my original first choice for lightweight 17's. They do have a little bit of a reputation for cracking under heavy track use, if you ask around the BFC Track/AutoX/Racing subforum. When I was going to get them, Tire Rack had them on backorder for several months then UUC had a sale so I bought D-force LTW5 rims in 17x8.5 (ET40). I got some 255/40/17 RS-3s from Tire Rack and use them for track and AutoX. They are slightly heavier than the K-1s but might be stronger? Other popular rims in this size range are the Apex Arc-8 (check for group buy if you can wait for them) and one of the TRM models (cheaper but heavier than the D-Force LTW5's, I think). If I had to do it all over again, I would probably buy 17x9" rims (D-Force or Apex Arc8) to provide better support for 255mm tires. Or maye I'll switch to 245/40/17 tires.

At first I thought 255's fit up front at stock ride height without rubbing and without spacers, but then discovered rub marks in the inner wheel well. Appears inside edge of tire was rubbing at full steering lock. So I put my 5pmm spacers back in.

[zj96sc]

I'd hold on until Apex does the 17" group buy, then get 17x9s and run 255s at all 4 corners.

GT172i just went from 18s to 17s on apex arc-8s during their last group buy and i thiiiiink went x9 and 255s but cannot remember. maybe he can chime in.

Depending on what the money looks like when the group buy pops up I may do the same. I love sidewall and I love the prices on 17" tires. 2-3 sets of tires will pay for the wheels.

edit: the arc-8 17x9 is 17.4lbs, x8.5 is 17.0lbs.

[Crickett]

http://www.apexraceparts.com/assets/images/productimages/wheels/NewARC8/17arc8/Arc8_17HyperBlackAngle800.jpg
:drool Do want . . .

[tian647]

Thanks for the thoughts here, surprised to hear that 255s fit with 5mm spacers on, would have expected to need to roll the fender lip for those to clear.

I have another car for playing in while this one just sees commuter duty so I don't need the ultimate setup, just looking for something that glides over potholes better than now - feels like the wheels are made from lead encased in concrete. I'm sure new shocks/struts will help that too, Bilstein HDs on OE springs are queued for install.

Related question, how bad do 255s tramline? I bought this car on Sumitomo HTR IIIs even now on 225s it wants to follow the contour of the road pretty badly. I suspect that's affected by cheap tires and maybe alignment but the width likely does have some impact too. I'm planning either Z1 Star-specs or Kumho XS, FWIW.


Christian

[GT172I]

Like zj96sc said, I did go from 18" Style 71's to 17x9 ARC-8's (the exact ones Crickett posted) with their last group buy. I absolutely love them. I went 255/40/17 square for rotations like tian said plus more rubber up front reduces understeer. Certainly doesn't hurt that a full set of Ventus V12's only set me back $400 (after rebate).

I haven't had any problems with rubbing and I don't have any spacers. My car sits about a half inch lower than my other 330Ci sport with OEM suspension (maybe more, I haven't measured). I might add a spacer later to the rear to get the same flush look out back. I'll double check for wheel well marks tomorrow when I adjust my fogs. When I researched for my purchase I recall APEX saying no spacers were required for 17x9 on e46's. The e36 needs some but we're fine unless you're running race rubber that runs wider that normal.

I've noticed and thoroughly enjoyed the lighter weight (~7lbs per wheel). Turn in is improved, ride quality is similar (minor improvement, but think the impact is reduced with the lowered ride height), responsiveness is definitely better and I can't wait to get them on the track. Most apparent change is the overall sexiness increase. I haven't had any problems with tramlining but I attribute that mostly to the tire more than anything. When I had Yoko S.Drive's (on the 18's) they tramlined but haven't had that problem after switching to V12's. Feel like I'm rambling so I'm done for now; I'm clearly a happy customer and would recommend the change if you're considering it.

[LivesNearCostco]

I was also surprised, which is why I originally ordered 17x8.5" instead of 17x9"--I was going to run 245/40/17. You can test it somewhat by fitting your stock 135 rear wheels up front in reverse stagger. I did that for a few days before ordering the tires. Just don't run it like that on the track or in the rain--could be a recipe for oversteer.

I hear of many folks who roll the fender lip to clear 255 tires, but I think most of them are....
A) Lowered
B) Using lower offset, like ET 25 instead of ET38 or ET40
C) Using bigger rubber, like 255/35/19 or 255/45/17
D) Using coilovers that need big spacer or aggressive (e.g. ET25) offset to clear the spring perch

In my case I didn't hear the rubbing and it wasn't rubbing the fender lip at all. Just saw paint polished off inner fender well near the brake hard line mounting point. It's possible that paint got rubbed off by the PO who was running 19" rims (not sure what tire size) before he sold me the car.


Thanks for the thoughts here, surprised to hear that 255s fit with 5mm spacers on, would have expected to need to roll the fender lip for those to clear.

[derbo]

LivesNearCostco,

Our rear 135 is 18x8.5 +50. Run a 10mm spacer with it and you get what 17x8.5 Apex ARC8 will be like. Currently I am lowered with 18x8.5 +40 and 255/35/18 in the front and I have no rubbing issues in the front. You can definitely run a 255!

dang, this talk about 17s makes me want to get a set too. 17x8.5 +40mm. Tires are so much cheaper in a 255/40/17 than a 255/35/18! Thats the main reason for me to get these. Hankook RS3s are under $600 and Star Specs are under $800!

I am lowered and I rub in the rear currently with 255/35/18 18x8.5 +40. Fenders are rolled too haha. Chances are I will rub in the rear with these rims but cheaper tire choices than $300 each RE11 for my track tires will benefit in the long run.




Now to test my coworkers 17x8.5 to make sure it clears my front brakes..

[e3thekid]

derbo, what are you lowered on?

[az3579]

Whether it will clear the brakes depends on what wheel, I believe. I know for a fact Style 68's clear them.


I'm hoping my Kosei K1's clear, otherwise I'll have some wheels and tires for sale. Lol


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[derbo]

derbo, what are you lowered on?


Ground control coilovers.

[YoRuddy]

Do you give up a lot of handling responsiveness with 17's? What are the main benefits of smaller diameter rims?

[zj96sc]

my main driving desires to pick up 17s (arc-8s in particular) are lower unsprung, much cheaper tires, and more sidewall to absorb crappy roads. beyond that, aesthetically i personally prefer the look of more meaty tires and sidewall, but that's not really why i'm interested in doing it.

[derbo]

less weight overall per rim, and cheaper tires are my main goals for downsizing.

[yura]

Interesting thread. My OZ Ultraleggeras are in pretty rough shape, so I might also look into downsizing to 17's once those tires are worn out...

[acontzhp]

less weight overall per rim, and cheaper tires are my main goals for downsizing.

+1

[M0nk3y]

less weight overall per rim, and cheaper tires are my main goals for downsizing.

Moment of Inertia fun!

[zj96sc]

my main driving desires to pick up 17s (arc-8s in particular) are lower unsprung, much cheaper tires, and more sidewall to absorb crappy roads. beyond that, aesthetically i personally prefer the look of more meaty tires and sidewall, but that's not really why i'm interested in doing it.

by unsprung i mean.........sprung.

derp.

[MisterMotorist]

Somewhere in the weeds in my backyard are about 9 17x8.5 ACS Type III wheels off of my E36 M3 (r.i.p.). When I find some time, I am going to root through them and see if I have 4 good ones and I will try running a square setup. I have been thinking about this for a while - does anyone have pics of a 330 Ci with ACS Type III fitment?

[zhp43867]

I ran 17s for a while (Kosei K1s), and I still do for winter (M68s). I think they look a little too small on the E46. The Koseis were fun but you can find 18s that are light as well: the ARC-8 in 18", some of the BBS wheels (RG-R), OZ, Volk, and the Sportline CSL Replicas all come to mind right off the bat. The ZHP is about the whole package, and going to 17s sacrifices some of the aesthetic portion of that.

[derbo]

http://i23.photobucket.com/albums/b388/paintpro21/980610285_g72DY-XL.jpg

It does look small. hmmm.. Only reason for me to get new rims is because of cheaper tires.. :X

[LivesNearCostco]

Oh yeah, for looks go with 18"s. For cheaper tires go with 17's. For maximum track performance I'm not sure which is better... it seems the serious BMW race teams mostly run 18's but that could be to clear BBK's and not just for the shorter sidewalls.

[JAMFAM]

There is a part of the original question that still remains unanswered here.

I too am interested in whether 245/45/17's will work on the track with 17x8.5 wheels and a totally stock suspension...??

[danewilson77]

There is a part of the original question that still remains unanswered here.

I too am interested in whether 245/45/17's will work on the track with 17x8.5 wheels and a totally stock suspension...??

Yes...it will work depending on offset of rim.

[JAMFAM]

Yes...it will work depending on offset of rim.

OK, thanks.
The offset on the D-Force LTW-5's is 41mm, I think.

[danewilson77]

OK, thanks.
The offset on the D-Force LTW-5's is 41mm, I think.

Perfection.

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[derbo]

245/40/17 maybe a better choice for more tire options :)


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[danewilson77]

245/40/17 maybe a better choice for more tire options :)


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Yeah....good point....you don't want 45's with a 245 tread.

[derbo]

Ideally 255/40/17 is the exact diameter from factory. The 245/40/17 will read 1.6% slower on the speedometer. The 245/40/17 is 24.7inches in diameter while the 255/40/17 is 25inches.


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[JAMFAM]

Ideally 255/40/17 is the exact diameter from factory. The 245/40/17 will read 1.6% slower on the speedometer. The 245/40/17 is 24.7inches in diameter while the 255/40/17 is 25inches.

Yes, I understand that, but what about the 245/45 with those wheels?
The reason I ask is because a friend offered me a new set of Nitto nt01 at a deep discount because they did not fit on his car. I'm afraid they won't be perfect for mine, either.

[danewilson77]

Yes, I understand that, but what about the 45?

About 25.68" tall.

0.45 x 245 = sidewall = 110.25cm

> Where 245 = tread width (footprint), and 0.45 equals the percentage of tread width, that is the sidewall.

110.25mm x 2 (for upper and lower sidwalls) = 220.50mm.

Convert to inches (of bowls)... 220.50mm / 25.4mm per inch = 8.68 inches.

Total height = 17 inches (rim) + 8.68 inches = 25.68 inches.

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[JAMFAM]

About 25.68" tall.

0.45 x 245 = sidewall = 110.25cm

> Where 245 = tread width (footprint), and 0.45 equals the percentage of tread width, that is the sidewall.

110.25mm x 2 (for upper and lower sidwalls) = 220.50mm.

Convert to inches (of bowls)... 220.50mm / 25.4mm per inch = 8.68 inches.

Total height = 17 inches (rim) + 8.68 inches = 25.68 inches.

OK. So that is 25.68 inches from the ground to the top of the tire. With shock travel, I think that may be risky. I don't want to make mods to suspension
or fenders.

[derbo]

if you are near stock height, it shouldn't be a problem for clearance. However, your speedo will be reading 2.7% slower.

[johnrando]

Inches of bowls sighting... love it!

[danewilson77]

Inches of bowls sighting... love it!

Lol. It still gets me.

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[wsmeyer]

Inches of bowls sighting... love it!


Lol. It still gets me.

I don't get it...

[danewilson77]

I don't get it...

Read the thread below.


http://forums.bimmerforums.com/forum/showthread.php?t=1578455&highlight=Inches+of+bowls
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[JAMFAM]

Thanks to all for the help.
I'm going to skip the 45's. Couldn't tolerate the speedometer reading 2.7% slower. Maybe 2.5%, but not more ;-)