Underdog Posted May 4, 2008 Share Posted May 4, 2008 I have really been enjoying my new Koni/Swift setup. Over the last 2 weeks, I have become used to the stiffness of the new suspension and I'm looking forward to exploring the >25% firmness range. However, riding on 18" Rota Tarmac 2's with 225/40-18 Toyo T1-R's always makes me cringe when I hit the numerous imperfections on local roads/highways. I think my anxiety is also fueled by the numerous creaks/rattles that the car has over any surface less than immaculate. I know that this comes with the territory of a stiffer suspension, and I am wiling to accept that trade-off. However, I am wondering if the decision to go with 18" wheels was a mistake. I bought the 18" Rotas when the vehicle was stock height. I wanted to fill the fender gap a bit so I decided to go with an overall larger OD tire. Now that I am lowered, I love the look of the car but I'm wondering if a 17" wheel with 225/45-17's would be a better choice. First of all, the wheel/tire combo should be slightly lighter, or at least a lower MoI. The effect on gearing would be very similar (+1.4% for the 17's vs. +1.9% for the 18's) although that would depend on the actual tire. Also, the extra sidewall (101mm vs. 90mm) would give the car a little more isolation, assuming the same make & model (and pressure) of tire. That leads us to my question... Would the extra sidewall make for noticeable sidewall deflection during *spirited* daily-driving? Would the extra comfort over bumps, and possible lighter combined weight more than make up for the deflection? Let's assume we are talking Toyo T1-R's or other UHP Summer or UHP A/S tires. Thanks for your input! The Crimson Dynamo Link to comment Share on other sites More sharing options...
Underdog Posted May 5, 2008 Author Share Posted May 5, 2008 Any opinions? I'm guessing people either don't know, don't care, or the difference will be academic. The Crimson Dynamo Link to comment Share on other sites More sharing options...
hutru01 Posted May 5, 2008 Share Posted May 5, 2008 I say just stick with the 18s and try to avoid potholes.....You could always get thicker tires (like a 225/45 or 225/50).....That would absorb the shock a little better. Of course it all depends on how much room you have between your wheel and fender. I have 18s and I hate to hit potholes (even with bilsteins and pinks). Link to comment Share on other sites More sharing options...
Spec B Posted May 5, 2008 Share Posted May 5, 2008 Not sure if this helps.. I run 2 18" setups 18x8 with 225/40/18's and 18x7.5 with my original 215/45/18. The 215/45 setup rides noticeably more comfortably, but it is not a dramatic difference. The 225/40 setup provides a slight improvement in response..but it is very very slight and almost unnoticeable. Perhaps you should simply change to a 225/45/18 setup? Link to comment Share on other sites More sharing options...
whitetiger Posted May 5, 2008 Share Posted May 5, 2008 I forget how wide the tarmac 2's are but if they are 8" wide you may want to get a wider tire than a 225. Since you have stoct strut housings up front, you have to be careful how tall your tire is or it will hit the lower spring perch. A 245/35/18 tire is very close in side wall height to a 225/40/18 tire. thais may be somthing you would want to consider. Link to comment Share on other sites More sharing options...
Underdog Posted May 5, 2008 Author Share Posted May 5, 2008 Thanks for the replies. My Tarmacs are 18x7.5, so my gut feeling is that 225 is as wide as I want to go with these wheels. My concern with going to a larger aspect ratio is two-fold: The effect on gearing will jump from +1.9% to +5.5%, nominally, and like Whitetiger pointed out, the stock strut housing has a very wide lower spring perch and I don't want any rubbing. 215/45-18 seems to split the difference by having a stock sidewall but a +4% effect on gearing. I don't think the 10mm reduced width is critical, but it doesn't seem like the right direction to go. The Crimson Dynamo Link to comment Share on other sites More sharing options...
robinlsb Posted May 5, 2008 Share Posted May 5, 2008 I am running cobb sways, BC/Br coilovers on 225 GY DS3's mounted on 7.5 X 17 BBs's. The Bcr's , I am sure are a little more stiff than your set up but I am not terrified of most potholes. The 225s have a slightly lower profile than stock but nothing compared to 18's I have seen. Side wall deflection is noticeably less (But remember that this a an issue with the DS'3) and I think that 17X7.5 on 225 is a pretty good compromise. I have manged to bend all four of the stock rims (and ruin 2 tires) at once so there is no real protection for BIG potholes. "Belief does not make truth. Evidence makes truth. And belief does not make evidence." Link to comment Share on other sites More sharing options...
Underdog Posted May 5, 2008 Author Share Posted May 5, 2008 Robin, you didn't mention what aspect ration your 225 GY DS3's are, but based on your comments it's a 225/40-17. That would have comparable sidewall to my 225/40-18 tires but a -2.2% effect on gearing. Now a 225/45-17 would have an additional ~5mm of sidewall compared to stock (10mm compared to my current setup) and be very close in gearing at stock+1.4%. You are right though, it is all relative and an errant sink-hole or nail will lay all my plans to waste. The Crimson Dynamo Link to comment Share on other sites More sharing options...
whobaru Posted May 5, 2008 Share Posted May 5, 2008 To the OP- I won't get anything larger than 17 for this very reason. Ride quality is often a much greater factor than the benefit of a potential mod. I almost got Pinks with HDs, but bucked up and spent more on KWs to ensure a better ride. Also, as you know, there's the slight loss of performance with larger wheels. The way I see it, 17s are plenty big. Then there's the expense, this saves a lot on tires too. Link to comment Share on other sites More sharing options...
hutru01 Posted May 5, 2008 Share Posted May 5, 2008 ^ How do you like the KWs? I have Bilsteins and pinks, I like them quite a bit, although I do wish the front end was a tad bit lower to fill the wheel gap. Link to comment Share on other sites More sharing options...
whobaru Posted May 5, 2008 Share Posted May 5, 2008 Here's where they sit: http://i180.photobucket.com/albums/x312/kagenmateer/IMG_3391.jpg Stay tuned... Link to comment Share on other sites More sharing options...
Underdog Posted May 5, 2008 Author Share Posted May 5, 2008 To the OP- I won't get anything larger than 17 for this very reason. Ride quality is often a much greater factor than the benefit of a potential mod. I almost got Pinks with HDs, but bucked up and spent more on KWs to ensure a better ride. Also, as you know, there's the slight loss of performance with larger wheels. The way I see it, 17s are plenty big. Then there's the expense, this saves a lot on tires too. This is very true. I am thinking that the 225/45-17 is sounding better and better, especially if I can find a good UHP A/S with reasonably stiff sidewalls. I love the Toyo T1-R's but I get nervous on the fringes of the seasons. Maybe I will keep the 18" Tarmacs for some really sticky stuff and get the 17x7.5 Tarmac2's from SubyDude for my A/S tires. The Crimson Dynamo Link to comment Share on other sites More sharing options...
Underdog Posted May 5, 2008 Author Share Posted May 5, 2008 Keeps getting better. Subydude is stocking 17x7.5 Tarmac2 in Full-Royal Gunmetallic which is the color I wanted originally (a little darker than the full-royal steel grey). Thinking about ContiExtremeContacts... Not sure though... The Crimson Dynamo Link to comment Share on other sites More sharing options...
Underdog Posted May 5, 2008 Author Share Posted May 5, 2008 Shelving this idea for now. Talked it over with my buddies and we agreed, it made no sense to change now, with only one season on the Toyos. I will bide my time and do some more research as to how many options I really have. I was getting kind of excited for something new though... Also had a positive experience coming back from lunch... read about it here. The Crimson Dynamo Link to comment Share on other sites More sharing options...
whobaru Posted May 5, 2008 Share Posted May 5, 2008 The unsprung weight's inability to snap back to the ground too quickly is the key. This is why a stiffer coilover can ride more comfortably. This is my understanding after many, many hours of researching coilovers. So, I plan to keep mine fairly stiff. Link to comment Share on other sites More sharing options...
Underdog Posted May 5, 2008 Author Share Posted May 5, 2008 The unsprung weight's inability to snap back to the ground too quickly is the key. This is why a stiffer coilover can ride more comfortably. This is my understanding after many, many hours of researching coilovers. So, I plan to keep mine fairly stiff. In this case, adjusting the Konis only alters the rebound setting. This is something I had forgotten since purchasing. It makes much more sense now that the stiffer settings will not increase bump absorption stiffness, rather it will better control the unloading of the spring and the return to normal-state. The Crimson Dynamo Link to comment Share on other sites More sharing options...
whobaru Posted May 5, 2008 Share Posted May 5, 2008 That was my point. Link to comment Share on other sites More sharing options...
Underdog Posted May 5, 2008 Author Share Posted May 5, 2008 Gotcha In this case, repeating and elaborating was a mental process I needed to go through to achieve understanding. The Crimson Dynamo Link to comment Share on other sites More sharing options...
whobaru Posted May 5, 2008 Share Posted May 5, 2008 As with any higher learning. Link to comment Share on other sites More sharing options...
Hanger Posted May 5, 2008 Share Posted May 5, 2008 I'm thinking to downgrade to 17" because of the growing potholes problem in my area ○ ○ ○ Instagram: itshangertime :spin: ○ ○ ○ Link to comment Share on other sites More sharing options...
whobaru Posted May 5, 2008 Share Posted May 5, 2008 I just wish 17s looked as pimp as 18s. Link to comment Share on other sites More sharing options...
Hanger Posted May 5, 2008 Share Posted May 5, 2008 Slam the car!!! ○ ○ ○ Instagram: itshangertime :spin: ○ ○ ○ Link to comment Share on other sites More sharing options...
whobaru Posted May 5, 2008 Share Posted May 5, 2008 I'm not sure which would be worse. Slamming it is prolly worse than large wheels. Link to comment Share on other sites More sharing options...
Underdog Posted May 6, 2008 Author Share Posted May 6, 2008 No slamming, no way. I love the way it looks now! My recent discoveries with the rebound adjustment on the Konis has definitely helped, but I will still likely switch over to 17's in the future. Bling just doesn't mean as much to me as comfort and performance. :shrug: The Crimson Dynamo Link to comment Share on other sites More sharing options...
whobaru Posted May 6, 2008 Share Posted May 6, 2008 Function before fashion. Otherwise you'd be bordering on ricer. Link to comment Share on other sites More sharing options...
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