I did some rim/tire test fitting this weekend, and I found some interference with the race tires I'm planning to use. The wheels have enough offset that I can fit the tire's under the fenders (turning will require some flaring of the front fender), and the rears fit fine. The problem is the front inner fender. The tire hits the inner fender before the suspension is anywhere near being fully compressed. The rim is a good 1 inch away from being tucked into the fender when the tire hits the inner fender. Turning the wheel makes the problem worse.

I did do some test fitting with just the rim. No problems, so I know the probem is the tire.

Anyway, my question is how many of you used a BFH to gain clearance on the inner fender? Another option would be to use a spacer and modify the outer fender. Perhaps that's a better option? What did you guys do to run tires that were much larger than stock on the front? Any suggestions/advice is greatly appreciated.

Another option would be to go with a smaller diameter, narrower tire on a smaller diameter rim, but I'd like to see if there's any way to get these to work short of having custom fender flares made.

 

Inner fender = fender liner?

Is removing it an option?

 

Fender liner is gone. It's rubbing on the metal part of the inner fender in front of and behind the shock/spring.

 

thats not the fender anymore...that's the car's tub.

 

What class and what car? Rules may dictate what you can and can't do to fix the problem.

 

Yes, I suppose I should have been more specific.

As for rules, there aren't any rules since the car is mainly being used for HDPE. I'm wanting to run in ITS in a year or so, that's why I'm a bit hesitant to make any major modifications to the outer fender or inner fender (unibody tub).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 117 &raquo;</TD></TR><TR><TD CLASS="quote">... Another option would be to use a spacer and modify the outer fender. </TD></TR></TABLE>

That would be the typical way to resolve the issue.

K

 

If it's rubbing the tub you may want to get wheel spacers, but then you risk rubbing the outer fender. I rub at full lock, but I'd rather rub the tub and not use spacers...

 

How frigging big of a tire are you trying to stuff in there?

Also - keep in mind that IT has wheel width limitations.

 

It would be most helpful to know what size wheels and tires they are, and what offset the wheels are. What kind of car might be helpful too.

 

It's a 98 Prelude, and I'm trying to fit 245/45/16s on it. No flames, please The wheels are 16x8s with +50mm offset. Before I get flames about the size, let me try to justify my decision. I originally ran with 225/50/15s on 15x7 Kosei rims with +45mm offset. That setup works very well, but I'm looking for something that's a bit wider. I thought about running 15x8 Kodiaks with 225/45/15 Kumhos or Hoosiers, as the Hoosiers are almost as wide as a 245 "regular" tire. However, being that the car is just for HPDE, I'd rather stick with a cheaper tire like the Kumho.

After looking around a bit, I bought a set of 4 RX7 rims for less than one 15x8 Kodiak, so I wanted to give them a try. The bolt pattern is right, but the center bore is a tad big. No big deal, I made a set of hub centric rings on the lathe rather easily.

Stock tires on the Prelude are roughly 24" OD. A 225/45/15 is 22.8" OD and the 225/50/15s I was running are 23.8" OD. Kumho specs their 245/45/16 with an OD of 24.4", which is just a bit over the stock diameter. A friend that races in ITS runs 225/50/16s with a good bit of success, but he does say that the tires can be overworked if he pushes too hard. That's why I wanted to go with something wider to spread the work over a larger area, and hopefully keep tire temps in check (plus, the 245s would give me longer wear life, right?). I know that the 225/45/15 will give me a gearing advantage, but I do have a ProDrive FD on the way, so I'm hoping that helps with the larger OD than stock tires.

 

No flames here, the Prelude is fairly heavy with a big front bias, it needs more than a 225 to work really well and to do that you need to go to at least 16". If memory serves, Mazda tends to use fairly large offsets on their wheels so you may need to consider a spacer. To do it right you would probably also need longer wheel studs. The wider, bigger OD tire should reduce tire temps and overall loads enough to help. The small gearing increase won't hurt much on track.

One important thing to remember is that if you do switch to ITS, you can't run those wheels or tire size. As far as your friend running 16's, I thought ITS was limited to a 15x7 and did not allow 16's at all?

Does the tire hit the top of the fender when the suspension compresses or on the inside face when turning the wheel to full lock? If it's at lock, just don't turn the wheel all the way in the pits, you never need nearly that much steering lock on track. If it's hitting on the top, would the 1" or so you could change with different offset help enough to matter? Is an increased ride height or stiffer spring worth the extra tire size if the problem is under suspension compression?

 

He runs a 16x7 with a 225/50/16 Hoosier without many problems. He does rub here and there. The stock diameter tire on the 97+ Preludes is 16, so that's why he has to run a 16x7. I'd use the 225/50/16, but the 245/45/16 is wider and smaller in OD, that's why I'm interested in it. IIRC, the 225/50/15 is almost a full inch larger in OD than stock!

I need to post pictures, but the tire is hitting the side of the inner fender (unibody tub) right on either side of the upper control arm. It's not hitting the top of the fender well since the tire bottoms on the inner side first. I know a spacer will take care of that problem, and more negative camber will make the problem worse (no camber kit on the car, yet), so if I don't want to use a BFH to gain more clearance a spacer will be mandatory. However, the tire doesn't fit under the sheetmetal fender now if turned more than around 15 degrees with suspension compression, so a spacer will make this problem worse.

So, since a spacer looks like the best option, the fender would have to be severely flared. Has anyone gone about making their own fender flares? I don't want anything pimpy, just something big enough to cover the tire and allow for proper steering and suspension clearance. Has anyone made their own flares out of fiberglass or something similar? I don't think I'd have to do anything to the rear other than roll the fender, so I just need to make a set for the front, if I decide to use this size tire.

The other option I'm considering is a 15x8 Kodiak with 225/50/15s or 225/45/15s, but as stated before, tire temps are a concern. It is an HPDE, so maybe the smaller 15s would be fine for now. Or maybe just run the same setup that David is running on his ITS Prelude. It's certainly less expensive than Kodiaks (Rota 16x7s with 225/50/16s), but I'd hate to put such a large OD tire on the car.

I am trying to get some "volume" pricing on 15x8 Kodiaks if anyone is interested.

 

What is the offset on the wheels you're using?

 

+50mm. Stock is +55mm, but it's a 6.5" wide wheel.