Kosei K1 TS - 17x9

asian312 · 08-29-2006, 11:03 AM

Well here goes...I hate posting a question like this.

I've been pouring through the pages recently regarding tires, wheel sizes, and offsets and finally all that munbo-jumbo makes at least a small bit of sense. I'd pretty much settled on a 17x8 due to the headach of finding a proper fitting 17x9 that was decently priced. Well long and behold while searching the internet I came across a picture of a gen3 RX7 with 17x9 Kosei K1 TS in the rear. I jumpped on TireRack and they are not listed. I hit Kosei's semi-english website and they are listed in +35 offset. Quick call to TireRack expecting to hear, "No we dont have those." But instead I get, "Yep we have those in light grey and silver." Incase those that dont know what wheels I'm speaking of, here's a link:

http://www.tirerack.com/wheels/Displ...Silver+Painted

So they are 17x9 (+35), weigh in at 16lbs for $259 ($20 more than the 17x8). So I'm trying to summerize all the data on 17x9s that I can and trying to rationalize this all in my head.

Why 17x9? Because that's what's needed for 255/40/17. And provides the tire options to run 235/45 and 245/40

Do they fit? yes ( http://www.martincheck.com/wheel_tire_fitment_FAQ.html ), but is it safe to have the tire that close to the rear inside control arm?

How much lateral travel does a tire have during track condition corning loads?

If I understand correctly adding a 5mm spacer will move the wheel out from the center of the car effectivly changing the offset from 35 to 30. Will this solve the problem in the rear?

Rubbing? Fender rolling? yep, a big helping of my baseball bat is in order. Car will see minimal lowering (1"-1.5") and these are track specific tires that will be shielded from Houston's endless potholes and construction.

Suspension is at a tossup at the moment. Pocket book and sensability say Konis with H&R OE springs. Inner child wants JICs and a vacation in California. Ultimate deciding factor, Fiance's rear end driving around town (think Koni/H&R wins).

And lastly
7. I have searched for and read the FAQ's, Tech Articles, and threads on wheel and tire fitment:
a) Yes, but I just need someone with experience to validate my choices

Nanan · 08-29-2006, 11:52 AM

Quote:

Rubbing? Fender rolling? yep, a big helping of my baseball bat is in order. Car will see minimal lowering (1"-1.5") and these are track specific tires that will be shielded from Houston's endless potholes and construction.

You should have no problems with rubbing on the lca/uca/fcb but you will rub the inner fender well on hard dips unless you roll the wheel wells. I am running a set of ProKit springs and I ended up with a good 1.75" drop so I had to roll the hell out of the inner fender wells.

wret · 08-29-2006, 01:11 PM

The +35 offset should be fine for 255/40/17 tires. You do know these will stick out quite a bit right? Even with aggressive fender rolling, you will need to keep the suspension high/stiff to keep from rubbing the fenders.

asian312 · 08-29-2006, 02:24 PM

That I do. I dont think the H&R springs will be stiff enough alone to keep the car from rubbing, but since they are only 1" drops that hopefully will provide enough height.

mavisky · 08-29-2006, 03:05 PM

I was looking at these exact tires myself as I get a small discount through Tire Rack for purchases, I still may go with them in the long run too. If you go through with the order let me see some photos.

asian312 · 08-29-2006, 03:18 PM

I shall, but it'll be a month. Kinda in a catch-22. I need to tend to more pertant matters (brakes, wheel bearing, alighnment, etc.) so I can run in Oct. Driver's Edge DE. Which of course provides me with my discount for TireRack =)

NextGear3 · 09-18-2006, 01:09 PM

I have 17 x 8 +35 with a 235-45-17 and it is rubbing the fenders some. i have got to roll them now.

diambo4life · 09-18-2006, 01:49 PM

It's scary how similar they look to mine. 9" width will rub hardcore.

asian312 · 09-18-2006, 02:13 PM

Next and Diambo, I'm curious if your car is lowered? And if so how much? Do they rub on the street and/or on the track?

diambo4life · 09-19-2006, 10:17 AM

Yes, it's lowered. Well over 2" all around. Maybe more than 2.5" in the rear. I don't recall. I only run 17x7 (with 215/45 or 225/45 rubber) so rubbing issues are not really my concern.

You typically can lower a 1g more than you can a 2g before rubbing. My buddy's 95 had barely a 1.75" drop and it would rub the tires very easily with 17x8's.

I would get hold of Sean (Tevenor) and see what he has to say about the best wheel application for your car.

jtmcinder · 09-19-2006, 02:05 PM

People keep asking about 255s on 2Gs. It can be done in a way that allows you to run soft lowering springs, but it takes some work. The problem is that you need to space out the rear upper arms when you lower a 2G (to correct camber), but spacing out the rear upper arms makes it less likely the tires will tuck inside a rolled rear fender lip. But, if you're going to run soft lowering springs, you need the rears to tuck.

Solution: don't space the upper arms out to correct camber; get someone to make you a set of offset bushings for the inboard ends of the lower control arms.

- Jtoby

asian312 · 09-19-2006, 02:32 PM

Thanks for the tips diambo and Jtoby. I'll give an update when I get them on the car.

asian312 · 10-05-2006, 11:07 AM

Glad to say after some much nervous nail biting over the fitment of these...they work. Pictured below are Kosei 17x9-35 w/ Bridgestone Potenza RE050A in 255/40/17. I decided to test them out on the streets for a few days before heading to the track later this month. Thus far I have not experienced any rubbing on the front/rear control arms or on the fenders. This includes stop-go traffic, speed bumps, highway, etc. I'll take them back off this weekend to check the inside wall of the tire to confirm. Haven't been able to test the grip or handling capability, but inital feel is phenominal. I only know of one set of decent S-turns in Houston and the car feels very stable and planted compared to my stock wheels/tires. Also at the moment I am still at stock ride height. Enjoy the pics...more to come.

asian312 · 10-05-2006, 11:09 AM

Front and Rear clearance

jtmcinder · 10-05-2006, 12:41 PM

Inside clearance is more than enough, but they are never going to tuck in. The easiest way to verify this is to jack up one rear corner, remove the shock/spring combo, and cycle the wheel up and down with a jack. I think this will prove that rolling the inside lip of the rear fender is a waste of time. Luckily, your car is so high. It'll take a pretty nasty bump (or a trunk full of lead) to cause any contact.

- Jtoby

asian312 · 10-05-2006, 01:06 PM

I agree, and will probably forego the rolling of the fender. I'll be installing the suspension this weekend so we'll see how it does with a 1" drop.

jtmcinder · 10-05-2006, 01:51 PM

What are your new rear springrates? Hope they're 375s or stiffer....

- Jtoby

Ludachris · 10-05-2006, 02:02 PM

Looking at those pics makes me wonder - is he going to have room for camber adjustments? It looks pretty close to the suspension as it is now. I'm not sure how it works on a 2G so I thought I'd bring up the question.

asian312 · 10-05-2006, 03:28 PM

I went with the Koni/H&R setup since this serves as daily driver and track training wheel. I believe I read the spring rates were

Front - 430
Rear - 260

I'm not sure how it affects camber adjustment, but from what few sources I've found people have managed. On the fronts its done by modifing the mounting points to the body for the upper control arm. Or via the position of where the lower control arm connects to the upper control arm (made by SPC). The rear are done by adding spacers to the upper control arm mounting point to the body. This was partially an experiment as the number of instances with DSMs running this size wheel and larger are scarce.

jtmcinder · 10-05-2006, 06:26 PM

Quote:

Originally Posted by Ludachris

Looking at those pics makes me wonder - is he going to have room for camber adjustments? It looks pretty close to the suspension as it is now. I'm not sure how it works on a 2G so I thought I'd bring up the question.

2Gs have double-wishbone, oh fearless leader, so the knuckle always tilts with the tire, so camber adjustment will have no effect on inside clearance.

Asian -

H&R 260 rears ain't gunna work, dude. One good bump and tire meets fender. Sell them and get a GC kit with 550-650 fronts and 375 or 400 rears. Seriously.

- Jtoby

1stGenRocks · 10-05-2006, 07:01 PM

Quote:

Originally Posted by jtmcinder

Solution: don't space the upper arms out to correct camber; get someone to make you a set of offset bushings for the inboard ends of the lower control arms.

- Jtoby

any info on where/how i could get ahold of a set of these?