Forgive me if this has been addressed, I searched and couldn't find the specific answer i'm looking for. Apologies in advance for the wall of text

After 2 seasons in a local time attack series i've put in far too much development time/money into my EM2, and will probably keep this car as a track toy (hilarious, I know) until I blow up the current motor (D17A1 #2). I've been invited to join a local road racing series which will involve gutting the car and putting in a full cage, but before I decide on that I need to get the tire situation sorted out as i'll be continuing on with time attack regardless.

Currently running 215/45/16 Ecsta XS on 16x7 Konig Feathers, rolled fenders with a drop that varies from 1.5-3". Camber adjustment for F/R (-1.5, -2.0 currently). Next season i'll be going with R-comps, not sure what kind yet as they offer varying sizes.

Ideally i'd like to hear from people who have tracked their cars successfully (e.g. without rubbing) on the largest possible wheels/tires:
What are my options for fitting the most rubber under the car? From a rotational mass standpoint obv i'd like to go with 15" lightweight wheels, but from what i'm seeing the biggest tire I could fit with those would be something like a 195/50. Weak.

I'm thinking something like a 16x8 wheel might be the largest possible, but finding decent r-comps in 16" sizing is proving difficult.

The knowledgeable track gurus who i've come to depend on for advice keep telling me to get a set of lightweight 17s (e.g. RPF1s), as my options for tires increase dramatically in that size, but i'm very hesitant to run such a large wheel due to A) rotational mass and B) my 17" rice wheels (215/45/17 tires) come VERY close to rubbing with track use, so i'm not sure that I could even stick a 225 on there like the RSXs run. Are these guys crazy for telling me to go with 17s?

 

Your car came from the factory with 185/65-15 tires, which is bigger than 2000 and older Civics, so you should be able to use tires that have a bigger diameter than those cars can. With a similar outer diameter, unless you go crazy with width, any rubbing issues result from your lowering the car. You may want to consider adjusting or changing the suspension so that it's not lowered as much, which will give you enough clearance to take advantage of tires close to the stock outer diameter. You may need to decide whether to make your car primarily a show car or a track car.

You are correct that there are not many R compound tires in 16" sizes for older Civics. However, there are some in the slightly larger sizes that your car can use. For example, the Toyo R888 is available in:

195/50-16 - 3.2 percent smaller diameter than stock - mounts on wheels 5.5-7.0 inches wide
225/45-16 - 2.0 percent smaller diameter than stock - mounts on wheels 7.0-8.5 inches wide

The Kumho Ecsta V710 is available in 215/45-16, the same size you say you're using now, but the diameter is awfully small for your car, 3.5 percent smaller than stock.

For 17" wheels, the R888 is available in 215/45-17, which should be a perfect match for your car. (The R888 is available in 205/40-17 and the V710 in 215/40-17, but those tires are a bit too small in diameter for your car.)

Again, though, what is hurting your ability to take advantage of some of these tires is the slamming, so your best bet may be to undo that if you want to use your car on the track.

 

Wow, thanks for the lengthy reply! For some reason this thread was moved from the 01-05 forum - I posted there as I was hoping to hear from other 7th gen owners who've had experience stuffing large wheels/tires on an em2, but i digress.

First off, I have the weakest of civics in that my stock tires were 185/70/14 - an 'SE' in Canada, probably a DX or 'Value Package' in the US. I should say that attempting to replicate the stock diameter isn't really my goal, I simply want to get as much tire on as possible. I don't really care about speedo accuracy.

I suppose my OP was a bit confusing - I have tracked the car extensively on the current setup, and when I encountered rub (on a highway trip in BC, with the 17s on) I did indeed raise the rear until the rubbing stopped. At my last event I hit a new personal best and it was agreed that to knock off any significant time i'd need to step up to a wider/grippier tire. That or a K20, and unfortunately I don't have $6-8K.

In terms of track performance, I'm currently running faster than every RSX-S at my local 'hpde' event (this after 10 events/season), with the exception of a 250hp/255-wide tire competitor who also knows how to drive (he ran a 71.35, my PB is 72.60 ). I know that sounds hilarious, but keep in mind I have the a/c delete mod and iridium plugs (lol).

Anyways - I'm curious about the 17s. Has anyone with an EM2 run a 225/45 or 225/40 (lowered/rolled fenders)? Is 215 as wide as I can go?

 

I realize that replicating the stock outer diameter isn't a goal in track use, but it's a good guide to how much room you have in your wheel wells. Keep in mind, a wider tire is going to reduce your clearance, even if the outer diameter is no different, so you want to avoid a significantly larger outer diameter, especially on a lowered car.

Also, don't be overly concerned about treadwidth. What really determines performance and grip is which tire (i.e. make and model) you choose, and the treadwidth is relatively insignificant by comparison. A stickier, slightly narrower tire will always give better grip than a less sticky, slightly wider tire. For example, a 205-treadwidth R compound track tire will give you MUCH better grip and lap times than your current 215-treadwidth XS street tires (and the XS is one of the stickiest street tires you can buy). So the extra treadwidth of a 225 isn't going to make a whole lot of difference in grip, and as you already realize you could run into problems with rubbing. Rather than worrying about how wide you can go, I would just get an R compound in a size you know fits, and use it to get accustomed to R comps. Remember, track tires, like brake pads, will wear out quickly, so you can try something out, and if you aren't totally happy with them, it won't take long before you need to replace them and can try something else next time.

If I were you, if you have 17" wheels for the track tires, I'd get the 215/45-17 - you already know that that will fit, and anything wider probably won't. In addition to the R888, the Yokohama A048 and Kumho Ecsta V700 are also available in that size. The V700 is on a closeout special at the Tire Rack right now, $104 each, which is a great deal on an R comp. The A048 is $255 at Tire Rack and the R888 is $175 at tiresdirect.net Yes, R compound track tires are expensive!

Incidentally, I have a lot of track experience - over 200 track events (NOT an exaggeration), and over 100 as an instructor. I use 205/50-15 R comps when tracking the ITR, and stock-sized R comps (205/50-15 and 225/50-16) on the NSX. So I "practice what I preach".

 

I'll add a couple cents in on this conversation, as it pertains to the chassis I drive.

I've been able to run 225/50/16's on 16x7.5 +42 Kosei's without rubbing problems on stock metal work with a moderate suspension drop. Anything wider and you'll need to stagger your wheel set or do some metal work, in order to maintain proper suspension geometry.

The 7th generation Civics respond well to larger amounts of negative camber in the front wheels when pertaining to autocross, because the MacPherson struts rotate in a way that allows you to maintain a larger contact patch in tighter turns. I run near -3.8 degrees on the front of my car currently, and I may go a couple tenths further when I run R-comps after the car gets built. We'll see how the car reacts after all the work.

The rear of the 7th generation Civics, however, doesn't handle well with much more than 1.5 degrees of negative camber. It's entirely too skiddish, and that inconsistent control is magnified by stiffer suspension components.

 

Awesome information, thanks to both of you.

NSX - Good point re: size - I know i'll see a huge increase in performance going with r-comps, I just thought i'd see an even bigger increase if I stuff the largest possible tire in there. Also WOW @ the price of A048s... I'll cross my fingers and hope the V700s are still around when I can scrounge some cash together (no more events until Spring 2011).

Matt - By metal work I assume you mean rolled fenders (done), or do you mean pulling them as well (not done)? The camber advice matches quite well with my experience. Running -2.0 on my rears i've learned what the combination of cold tires/neg camber does on this car with a quick trip into the gravel trap and another close call. It does make it kind of fun for messing around though - cold or wet Kumho XS + sharp turn + elevation drop = 4 wheel civic dorifto haha.

I'm going to need to get a different kit for the fronts, as all I have now is an Eibach 'camber kit' that consists of a bolt, limiting me to -1.5 up front. What setup are you running?

Also i'll look into 225/50/16s.. might be an issue fitting them on a 16x7 Konig Feather though..? Pretty soon i'm going to have 5 sets of rims for this car :/

 

No problem at all. Most 225/50-16 tires are approved for mounting on rims 6.0-8.0 inches wide, so 16x7 is perfect.

 

Metalwork - cutting the inner lip of the quarter panels down and re-welding the panels at the newly created seam, or running fender flares and cutting the quarter panels and fenders to match the new opening.

Currently, this is my suspension/wheel/tire setup:
Hotchkis front camber plates
HKS Hypermax RS coilovers
Swift springs (11kgmm front, 13kgmm rear)
Tanabe 29mm front anti-sway
Mugen hard bushings (for the compliance bushings in the front LCA's)
ASR 32mm rear anti-sway
Function7 rear LCA's
16x8 +35 Work Ewing RS-Betas
Hankook Ventus RS-2 245/45/16's
-3.6 camber front
-1.8 camber rear
Cut/welded quarters and a front clip swap (which gives me about 25-30mm extra space)

 

Extremely impressive setup.. would love to see that thing in action. I'm going to pick up some parts from your list, this is way better than the trial/error i've been doing so far. Thanks guys!

 

Here's the first Auto-cross I participated in with the setup. I wasn't completely dialed in, and my sister isn't a professional when it comes to the camera... but it does give you an idea of the car in the corners.

http://www.youtube.com/watch?v=_u8i2jbkoWQ


PS. A lot of the things on my car were custom order and aren't available anymore, bud. Just as a forewarning.