Wheel Size/Back Spacing Issue w/17x9

[cyc6603]

I have been around Fj40s for many years and have always noticed discussions about 15" wheels. I understand that there are issues with having more BS than 3.5 or 3.75 due to interference with the TREs and possibly the Disc Brake Caliper. However it seems that most of the discussion is around 15" wheels.

I'm considering 17" wheels but don't fully understand if there really are any issues. I'm an engineer (so I tend to get pretty technical and understand in detail what I'm trying to do) and so before I dump lots of $$ on wheels/tires I would like to here from some of you who have already been down this road. I've done quite a few conversions on my 78 FJ40 and have always measured twice and cut once philsophy. So, I've searched and spent many hours and haven't really found the answer to my question.

Why is the backspacing seem to always be discussed as no more than 3.75". Maybe this is the issue with 15 or 16 wheels hitting the TREs or possibly the Brake caliper. It sure seems that going to a 17" wheel opens the the door for more BSing (maybe I'm missing something). Please help me understand why this would not work. I really want to use 17x9 with no spacers. Has anyone done this or had success with this? Thanks in advance for your help.

 

[KY Longhunter]

cyc6603 I've been waiting for someone to reply to your thread as I have wondered the same thing. If you go to a 17" rim would you eliminate the tie rod ends rubbing? The TLC ICON has 17" rims but of course it is custom from the ground up.

Most wheels I have been pricing have a 4" backspace and stock is 3.25" backspace requiring a minimum of 3/4 " spacer.

I would love to hear a little more discussion on this topic before I purchase new wheels. Cheers!

 

[cruzer971]

I had a set of KMC 17x8's for my 80 that were left alone in this world when the 80 died. Not to let them wither away, I fit them on my '72 FJ40. They had like 5" BS which kept everything under the 80. On the 40 the diameter was big enough to clear the TRE. Just barely though. Depending on how the wheel is machined out you may get too close, but mine worked. Having the tall tires on high offset wheels caused them to rub on the leaf springs on full turns. I had 315/70's on them and I didn't like the fit on the rear. There was very little room between the inside sidewall and inner fender. So I bought a set of 1.25" adapters to space the wheels out. With those on there, The clearance was good on the rear, and I could turn the fronts to full lock again. That put me back to the 3.75" BS, so that is what I would recommend staying with. The 17's clear the TRE's but you end up being too offset inwards with 5" BS and tall/wide tires

 

[KY Longhunter]

OK, good info. So I am considering some 8" rims with a 0 offset (i.e. 4" Backspace).

If I ran 285/70 on the 4" Backspace would I have any clearance issues?

By the way...I'm running a 2.5" OME lift.

 

[alumacruiser]

I am running 17"x8" with 4.5" of back spacing. Tire size is a 265/70-17 Geolander M/T. You can look up past ROTW - 'alumacruiser' to see a couple of pictures.

 

[KY Longhunter]

Well I broke down and bought some American Racing Mojave 17x8 and BFGoodrich MT KM2s (285/70R17). I think I will be alright on the TRE per pictures.

Does anybody know size of Lug Nuts? The ones they sent me are too small.