I have a 4th gen prelude with a 5 lug conversion. I currently have 17x7.5 RG II's running Toyo R1R's in a 215/45/17. I want to run a wider tire for road race use so the only choice I see out there is a 235/40/17. I'm willing to get a different set of wheels in a 17x8 to run the 235/40's but I'm looking for information out there on what I would need to do to make this work from those who may have done this. I don't have a problem rolling the fenders which I know I'll have to do but I was wondering also about the proper offset to get this setup to work on the inside. I've seen 17x8's in 35 and 38mm offsets. Will either of these work or is there one that's preferred? I've seen pics of 4th gens here with some really wide wheels. I don't know how much track use these cars see so I'm looking for feedback from road racers or autocrossers. And finally, are there any drawbacks running a lower offset even though I don't think the 35mm offset would be a huge drop. How much more rapid wear would this offset have on the bearings if any? Any knowledgeable feedback would be greatly appreciated.

 

is there any reasons you have to keep the 17s? i'd go down to a 16 at least, and up the sidewall then whatever widths and offset you run you'll have less of a fitment issue. and unless you need the gearing the shorter tires will give you better acceleration anyways.

but if you stick with the 235/17 you'll most fefinately have to roll the fenders with a lower offset. how low are you?

 

What is the weight of your current rim? +35 offset isn't recommended. If you want wider, you could get Nitto NT555's in a 225/40/17. Those would mate up to your current rim with no problem.

 

I run the baer track big brake kit with the 13" rotors. after my 20 minute sessions at the track i have absolutely no brake fade so I'd like to stick to those brakes. If I could go with a 16 I would probably be willing to do that for the track but that would mean redoing the brake setup. I'm not really low. I'll see if I can post a pic of my setup. I really like the R1R's and would like to stick to them. The R1R's are also a 140AA tire. Isn't the 555 like a 300? Does anybody have experience with the 555's? I know toyo makes nitto tires and the toyo's are of substantially higher quality. As my driving skills improve I want to move up to the R888 for track use so I am looking into farther down the road. Good input though.

 

you're most likely losing time with that baer kit. stock stuff seems to be adequate for people driving a heck of alot harder then you. good rotors and a good set up pads and you should be set. plus you don't have the weight penalty of the larger brake setup, less unsprung weight in the brake setup itself and less unsprung and rotational weight in the wheel and tire package. not sure if you're looking to be real competitive or not, but the MRW honda challenge car that won the national championship race at mid-ohio last season runs stock calipers and rotors, cobalt XR pads, stainless lines, super blue, and brake ducting. and i think he might be a hair faster, and possibly heavier.

just throwing ideas out there, but like i said, i'm not sure how far you're willing to take it to go faster.

 

17s offer much better selection of tires, and nothing in something as wide as a 235.

His current R1Rs would be waaay better than the NT555. The R1R may not be as good as the RE-11/Z1 star spec/XS, but it's still going to be leaps and bounds better than something like the 555.


To the OP, I would look for something with a higher offset, like +45 or so. I'm not sure how the 5 lug swap is going to affect the wheel/knuckle clearance, but on my 5g a 17x8 with a pretty wide 225 (wider than a street tire 225, certainly) still has fairly good knuckle clearance with a +45...and that will allow you minimal fender mashing. +35/+38 I'm sure can be made to work but there isn't any inherent reason that you need to run that sort of offset.

 

No particular reason to run that offset. I've just looked around here on one of the prelude pics threads and they couple of people that i saw using a 17x8 were running that offset. Maybe it was for the look. I didn't want to make assumptions about people's setups. My build was originally for street but now I have more power than I would ever need or be able to exploit on the street. I was at a nasa event in arizona on april 11th and it was alot of fun being able to really run it legally if you know what i mean. I don't think I would realistically have the funds or time to be really competitive but I would like to be competitive in the events or classes that I do run in. I guess another good question would be this: for someone in the situation I'm in, how much of a difference does that 20mm section width make? If it's gonna be more of a headache than it's worth I wouldn't consider it. I think the 17's are here to stay. And working with what I have, is it something doable. I just think there might be a lot of people on this situation even though they may not all be prelude owners.

 

I put pics of my setup in my album if anyone wants to take a look. I don't know how to get them in the post from there...

 

If this was your first event out (congrats), I don't see much point in throwing out what I'm presuming to be a perfectly fine set of tires and wheels. The additional width will probably be noticed by someone who is competing against the clock and experienced....but if you're not then I wouldn't sweat it yet. Do correct me if I'm making wild assumptions about this though

 

I've tried various combinations on my track car.

Right now I'm in between tire sizes, and planning to mod the fenders to fit 245/40/17s for the additional width.

My prior setup was on 225/45/15 and 225/50/15 Hoosier R6 tires on 15x7 and 15x8 wheels, both with +40mm offset. Trust me, they're much wider than any 225. Actually closer to a 245 wide tire. They're just a bit narrower than the 245/40/17. A friend of mine used to run 225/45/16s, and he was VERY fast with them. He thinks he'll be faster on the 15s, but I think gearing is going to be a problem for him (he runs the 5.15 MF FD).

235/40/17 should fit no problem with something like a +45 to +48mm offset. You should be able to even keep your fender liners in the front, especially if you run a lot of negative camber (I run about -2.7 degrees up front). On the rear, you'll have to roll the fenders for sure, unless you run a lot of offset.

My current wheels are 17x8.5, +40mm. I moved up to 17s to clear my brake setup. I'm hoping to add a fair bit of power next season, so I need the additional thermal capacity.

With my current wheels, I can fit 225/40/17s on the 17x8.5s no problem. The rear fenders were already rolled to fit the 225s on 15x8s, so I didn't have to do anything. The front fenders ARE NOT MODIFIED at all. I have the fender liners and everything. This won't work with the 245/40/17s. I have fitment pictures showing that the fender needs to come out about 5mm or so to clear the 245s. The rear is worse, so I'm not really sure what I'm going to do in the rear.

I'd bet a 225/50/15 Hoosier is wider than any of the 235s you find. Not that I advocate going down to a 15" wheel. If you do that, you really need a brake package that has more thermal capacity than stock.

Before anyone says anything, yes the OEM brakes work great. In fact, they're better than most other OEM brake setups. However, if you run on a course that's hard on the brakes, you'll notice that the rotors develop hairline cracks quite quickly from the heat.

If I could fit an 11.75 x 1.25" rotor under a 15x8 Rota Slipstream (or better yet a set of 15x8.5 Kodiaks), I'd run 15s, but that's just not going to happen with Rotas. Maybe Kodiaks, but they're $400 a wheel!

 

It was my first time, thank you! Firebird's front straight is the dragstrip so you hit alot of traction/no traction sections as you come across the staging lanes. I ended up having to leave it in third to try and avoid it the last 2 sessions. There's another section coming out of turn 4 that I was in second and again just losing traction. That's when I got the toyo's. The are leaps and bounds better than the other one I had. Even so, during some spirited driving, coming out of a turn in second yielded some considerable wheel spin, hence the inquiry into a wider footprint as I could expect to run into this situation in the track.

Thanks for the info 117. I think you're right about the brakes. With the power this car has, I would apex later than other cars there and carry alot more speed down the front straight and have to get on the brakes a lot harder. I had the street pads on (i was actually in az to pick up the car!) so I don't know how things would have gone if I had the stock set up.

It's great to hear that I won't need to use such a low offset. My RG II's are a 45mm offset and there looks to be plenty of room in there up front, inside and out, so I guess I can get a good assessment what I'll be needing to do from there with the 17x8. I was just wondering why people here were running the 35mm offset. The rear will be another issue but one that I think will be worth it.

 

when you say roll the fender..do you mean cut the opening..or are you just turning a lip on her for a lil' clearance