40 Inch Tire Talk.

UNSTUCK

But stuck more often.
So the 35's are sold, the one tons are sitting in the garage, and I'm a phone call away from 40's. I have a nice set of 15 inch wheels that I used with the 35's, that I can't seem to sell. So now, I'm thinking about using them with my 40's, which will be Iroks.

I was planning on buying steel 17 inch wheels, but I have these much nicer 15's. So the question is, what is the performance difference between 15 and 17 inch wheels and 40 inch tires? I've heard that with 40's aired way down, a 15 inch wheel can just turn inside of the tire? Any truth to that?
 

LT.

Well-Known Member
I have yet to run a 40" tire on a 15" wheel but, I have run an IROK on a 15" wheel that was 42". The issue that I had with them was there was too much side wall and that resulted in some tire hop. I have also yet to run my 42" Pitbulls with the 17" wheel but, I am expecting better from the combo.

LT.
 

Tacoma

Et incurventur ante non
Location
far enough away
I was gonna say, lots of sidewall, and the attendant issues... which may or may not be issues for YOU. :D

Plus you'll have the dreaded Balloon Tire Syndrome. :shudder: :D
 

UNSTUCK

But stuck more often.
I kind of figured that would be the case. I think I'll wait a bit longer and see if I can get these sold first and buy 17's.
 

ChestonScout

opinions are like Jeeps..
Location
Clinton, Ut
I loved my 40s on 15" wheels. I also didnt have any problems with my 42s on 15" wheels. Both were TSLs.

The only issue I had was I had to grind the front brake calipers down on the dana 60 so the wheels would fit over them. I could see the caliper flex when I applied the brakes which always worried me. That would be the only reason I would go to a bigger wheel.

Having a little sidewall is nice IMO. Ya.....if you air them down to nothing they will hop and fold on themselves but I think you would have the same problem with a 17
 

notajeep

Just me
Location
Logan
I have run both a 40 irok on a 15 inch rim and now a 42 irok on a 17 inch rim. I realize that the sidewall to wheel size is about the same for both, but in everything except competion, I have been really happy with them. The 15's did require some caliper grinding. If you are starting fresh, I would say go for the 17ls. You are still dealing with a lot of sidewall on any 40/17 combo.
 

lewis

Fight Till You Die
Location
Hairyman
I ran bogger, tsl and Irok on a 40-15 combo. Lots of sidewall meant lots of sidewall pinch flats tears for both the bogger and tsl. I ruined 2 tires on each and had them down to about 8 psi. Nover had a problem with the Iroks though, could be cause i went to beadlocks and only went down to 10 psi.
 

ID Bronco

Registered User
Location
Idaho Falls, ID
I guess it's been said, but I ran 39.5's on 15's with no problems, aired down to 4-5psi. It is an early bronco, so not super heavy, but not super light either.

I say run the 15's if the wheels are nice, if not step up to 17's
 

Jinx

when in doubt, upgrade!
Location
So Jordan, Utah
I think it has been addressed, but for me the question would be can I make the 15" rims work on my new axles? If yes, then problem solved if not go 17"s.

I never realized the difference in one ton brakes before trying to put a 15" wheel over them. :D
 

lime chev

Member
Location
Idaho
are your 15s already 8 lug, I only run my 40s down to about 8-10 psi cuz I have a fat turd of a rig but with no problems, but I think that I would go with 17s that way if I was givin Krawlers I could run them:D
 
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rockreligious

NoEcoNaziAmmo
Location
Ephraim
I ran 39.5 IROKS on 16" beadlocks all last season, I liked it, no grinding, no hop, running at 8-10 lbs on a 4 seater buggy.. i didnt want to grind, but I wanted some sidewall flex without getting bouncy. very happy.
 

UNSTUCK

But stuck more often.
My rear 60 is 5 lug already, so I will be swapping out the front 60 8 lug parts to 5 lug parts. So there will be no caliper grinding. Doing that will cost a lot of money so saving money by not buying wheels will be nice. I could get Stauns later on down the road as well and be set.
I can get the 39.5 Irok for the 17 inch wheel for about $299. I would guess the 15 inch would be the same or just cheeper. I haven't looked into it. That is about my price range. Any better options out there? I want to stay around 12 -13 inches wide.
 
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