Wheel & tire selection help

[Iziks]

Probably getting ahead of myself since I just ordered my kit, but what else is there to do but look for wheels? Bad part about looking is you might find something you like. So I found a smoking hot closeout deal that I may not want to pass up if it works.

I realize there is a ton of data in the forum on wheel and tire fitment, and I tried to review it, but a lot of it is still Greek to me.

33 Hot Rod with IRS, Wilwood brakes and no fenders. I prefer a bit more sidewall than most, so I was looking at 18” wheels. This will basically be a street machine, but an autocross event is not out of the question.

I ran across a close out special for some new wheels - 18x12/45mm offset rear and 18x8.5/50 mm offset front. The only issue is the bolt pattern is 5x130. It seems like a lot of folks are using spacers anyways, so I guess I could go with a one inch adapter.

Looks like tires would be 295/35 rear and 235/40 front ?? That was what I could determine based simply on availability.

Multiple questions:

Will those wheels be a fitment issue?
Should I just stick with something more in the 10” rear - admittedly, going to 12” is more for the look.
Is it bad to be using the adapter or am I likely to need spacers anyway?
Assuming the wheel size is ok, how about the tire size?

Thanks in advance for any input.

[NAZ]

Why not buy wheels that fit without spacers?

Without fenders you can fit most any reasonable choice of tire, even some very wide tires. Under fenders, I've found that the following combo worked good and looked great:

Front -- 18x9x5.0" backspace with 255/35R18 tires
Rear -- 18x10x 5.75" backspace with 315/30R18 tires

[Iziks]

Why not buy wheels that fit without spacers?

I have not been able to find any 18x12 black wheels. Perhaps I am just not looking in the right place.

[NAZ]

Summit Racing has a good selection. If you are dead-set on all black and can't find what you like, you can always have a wheel you do like powder coated black.

[NAZ]

Rear Street Tires.jpgFront Street Tires.jpg

Here's what I'm using now -- some 16" wide tires under fenders. The wheel centers are black and the rims polished.

[RoadRacer]

295 is pretty narrow for a 12” rim. I run 295 on a 19x10. And 355 on a 19x13” rim

I don’t know the offset you’ll need at rear with an irs, sorry.

Nothing wrong with a 1” spacer and can be hard to find wheels to fit without, but I doubt you’ll find an adapter under 2”. I was forced to use an adapter cos 19x13 are commonly viper pattern but if I was you I’d look for the standard bolt pattern.

P.S. if you’re racing, even autox.. the more rubber the better

[Iziks]

Thanks for the input guys. After much more digging, I found a set of wheels I like that are 18x11 rear and 17x9 or 8 front in the standard bolt.

Standard bolt is 5x4.5, correct?

For front, is there any reason to go 8 vs 9 or vice versa?

On the rears, would a 295/40 be ok on 11”, or do I still need to go wider?

[NAZ]

Yes, bolt circle is 5 on 4.5". The 295/40R18 tires will work with rim widths between 10" & 11.5" and are ~27.3" dia x 11.6" cross section. Without fenders you can run these on the front and much wider on the rear. Choose wisely as it gets expensive buying more than once.

[andyw]

Iziks, I'm struggling with the same questions so thanks for asking. We're waiting for our kit in Feb and also have IRS and debating wheel sizes and styles.

Andy

[Brave Salmon]

For what it's worth, i would suggest you wait a lot longer before buying wheels and tires for your ride. As you build this thing you will find that you mind will wonder in a dozen different directions regarding configuration. You may now want fenders but not in a year. You may want to run without fenders now but then learn after the fact that your paint is afu from road rash thrown up from your tires. And then there is the ever present warranty concerns with those shiny new tires and wheels sitting in the corner long after the 6mo warranty has expired and you find they actually dont work afterall. We all believe the car will be done in 6 months but most of us have faced reality and the longer you wait for rubber and wheels, the longer you'll have them once on the road. Good luck..

[FF33rod]

What Brave Salmon said - your paint will be trashed in seconds without fenders. Even with the bicycle fenders on the front, positioning is crucial, need to get the rear of them as low as possible. Also, if you plan on building a roadster or run with the top off from time to time, expect pebbles/sand raining on you in the cockpit. So if you're not planning a high end paint job you may not care. That aside...

Your rear tire options are no different than the other rear ends that FFR sells, they all have the same track width.

The FFR manual does a pretty good job of detailing the max tire size and backspace you can get away with if you have fenders. Some of played around a little and "snuck" a little bit more tire in there but playing around can be expensive when you're guessing.

Without fenders, as NAZ said, your options are pretty open and you can run some pretty wide puppies, particularly on the back. Just pay attention to the back space. (Backspace and Offset are basically specifying the same thing, position of the wheel mounting surface. Offset is just relative to the centerline and backspace is relative to the inside rim. Lots of articles and calculators if you google it https://www.customwheeloffset.com/ti...et-calculators ) Per the manual, max backspace on the rear should be 6" and front is 5.5 - if you stick with those no matter what the wheel width is, all your varying is how far the wheel/tire sticks out from the body, not the distance from the body to the inner surface of the wheel/tire.

hope that helps a bit

Steve

[33fromSD]

Agree with all statements, this is one of the reasons I went full fenders.

Make your own determination obviously, my only input will be once you go-kart your chassis prior to putting the body on, pay attention to how much sand & gravel flies in your face and in the interior. That will give you a sense of what it will be like to run with no fenders. It surprised me how much sand & gravel I had to vacuum out of the inside of the chassis after I go-karted it and I only drove around the block 3-4 times.

Jim