Axle Trussing and CV's for 30"

If I'm going maximum 30" tires and front and rear lockers:

-Is it advised to truss the front AND rear axle?
-Upgrading the front shafts to 26 spline and beefier cv's

Has anyone used the birfield rings instead and the 22 spline front shaft? Also what's the recommended minimum width and offset of rim to go with a 30x9.5R15 tire? This vehicle gets driven on the road as well. I have 16" rims right now and don't like the tire selection almost all tires are E rated. Slowly planning my build and if I'm pulling the diffs to put in lockers, it could be a good time to truss the axle if it's needed.

I can't answer your axle questions.

30.9.50R15 is an interesting size, one I contemplated on my JB74. But I decided that a re-gear would 100% be needed.

Not the best choice of tyres in this size. As for rims BFG say 6.0 - 8.5" with the ideal being 7.5", however 'if' I'd gone for them, I was going to mount them on the 5.5" stock Jimny rims. They should fit fine, just a little more pinched in.

Having said that, 16" rims give you way more choice.

A 30.9.50R15 is 29.5" tall.

If you are in the UK, then my personal experience says tall narrow tyres work the best in many off road situations on UK terrain.

A 205 x 16 (205/80R16) is nice an narrow and 28.9" tall. So slightly shorted, but less mass and a lot more narrow.

If you are in the EU, then you can get 6.50 x 16 tyres. Although a bit of a challenge in the UK. These are slightly taller than the 205 at about 29" tall and slightly narrower. I think they could be almost the ideal size for a Jimny on stock gearing.

Although both of the above sizes really want nice narrow rims in the 5.5-6.0" range.

There are taller tyre options too such as a 7.50 x 16 (31.8") and a 235/85R16 (31.7") which would probably also suit a Jimny's wheelbase.

235/70R16 is 29" tall and the same width as the 30.9.50R15

Or if you want a true 30 inch tyre a 245/75R16 is hardly any wider but comes in at 30.5"

255/70R16 is 30.1" albeit slightly fatter.


I'm not saying don't go 30.9.50's, but there are plenty of comparable 16 inch tyres, that may save you spending out on new rims.

In my mind, trussing the axle is unrelated to the tire size, and whether or not it's needed is more a matter of where and how you will be using the vehicle. Rock crawling or similar is where you'll want to look into it.

Also, you make no mention of gearing adjustment, and as 300bhpton has indicated, it's going to be 100% required.

I forgot to add that this would be in conjunction with a transfer case re-gear. Trail gear 17/87 or a hiwow 15/75 gear reduction in hi/low. Don’t really plan on rock crawling at the moment but who knows? I’m based in Canada and I’m doing more deactivate forest roads to get to camping spots but we do have some pretty challenging roads/trails.

id like to save money and stay with my 16” steel wheels but they are all E rated tires and thus heavier. The skinnier tires are also E rated. Is it better to have a skinny E rated or light wider? I have found one tire that would be nice, the kenda klever r/t LT235/70R16

Just looking at the BFG site and the 235/70 is lighter than the 30.9.50R15

 
 

Thanks for checking. They're about the same 46 and 47. I'm down for a thinner tire but do you have any insight if a load ratting of 110 would still feel ok on road? As well as pushing a 46lb tire?