Oh, well... 33's it is then ;- ). Don't be fooled by the "rods for lift" nonsense. If the tires are too big, without stuff cut away, you'll grind right into that on a trail with full articulations, in addition to losing most of the down-travel.

 

I hear ya man. Im going to look into 18s seriously. See where that journey takes me.

 

Just to chime in here. As for the op questions related to long travel suspension. My research and hands on visual inspection has given me this opinion. Until real measurements are taken, this is just hypothetical. But at a glance, nothing has really changed in the suspension layout, design and function of the IFS, other than the 6d add on.
1. There is no tangible difference in control arm length on the Octa. The control arms on the front and tie rod ends are different part numbers, however, they seem to be "cranked" a bit for the taller ride height. There is no tangible size difference or length difference in front cv axles and boots vs the stock setup. All new Defender front axles use the same boot kits including Octa. The front cv axles are different part numbers, but do not seem to be any larger than the stock. units. Possibly made stronger for the added torque. Front wheel bearing/hubs are the same as big brake/p400 caliper equipped defenders.
2. Rear suspension arms are the same as all other variants with the exception of the rear upper arms which are the same as the D5 and L405 which do not show any tangible difference than the stock defender units. The rear axles, cv boots and hub bearings seem to be octa specific. Likely beefed up for the added torque.
3. 6d suspension will provide some more axle travel by default vs stock because of the lack of static sway bars. In addition, rear axle travel has been extended with longer rear dampers. This was evident when JLR snuck in longer dampers on air suspension vs coils giving the air suspension vehicles more rear axle travel. All suspension components other than bags and dampers are the same on coil vs air. Similar when you go to the 6d system. Fundamental difference is the electrohydraulic dampers.

Proper Long arm/travel suspension on the new defender would involve a lot of re Engineering. Not impossible, but would remove/replace most if not all of the factory suspension, similar to what was done with the Dakkar. Litterally all of the 6d, air suspension, and technology have been replaced with tested and proven coil over suspension. I dont believe the Dakkar has much more suspension travel since i believe they are still using the factory axles which limit viable travel. And in addition, more travel may not be needed since the defender has decent travel in stock form.

Would be cool to see an octa on an RTI ramp vs stock air equipped vs modified coil suspension to see how much tangible difference in travel there really is.

The intriguing thing to me is how much beefier the rear axles and hubs are. Knuckles are different part numbers, but nothing can really be seen as different. But if the rear axles have beefier shafts and cvs are larger, this would be a cool upgrade to a stock defender.

 

I gotta be honest. Suspension travel has never crossed my mind with the L663 as an issue, so I don’t think longer control arms is necessary. I run 33’s (because I didnt want to trim - I’ve since changed and wish I had slightly larger tires and a body lift ,which I don’t want to pay for). @jwest I think you’re spot on about 34”s being the sweet spot for L663 (standard, not speaking for Octa as I don’t know). In mine, I’ve been to the toughest trails in Moab etc. This thing is fine out of the box. Suspension travel isn’t the limiting factor on this platform. Is it?

 

Completely agree. It helps to have a bit more in the rear which is easy to get with longer rear dampers. Keeping wheels on the ground adds more contact patch. But in stock form, the defender has better axle travel than a stock Grenadier. So i would not say that axle travel is a hinderance. Also, if going to long travel, you will lose the ride quality on the road, which is what is so nice on the defender. Good balance of on and off road ride quality

 

Dont disagree with any of the above its a very capable truck. I also love how nice it is to drive on the road as my jeeps in the past did NOT perform the same. The reason for my ask around control arms had less to do with articulation of travel and more around ride height as a means for bigger tires and more side wall. I just do NT have the expertise the last few folks who have kindly chimed in possess. I just want more sidewall to air down and I havent found anyone who can do an 18 inch conversion to my 90 V8. !8’s with 34 inch rubber would be amazing.

 

@sarek You are only about 4 hours from me is this something you could help me achieve?

 

That's all very interesting. Do you know where the wider track is created? It isn't the wheels obviously because they're all the same offset, and you mentioned hubs being similar so something has to be either longer (which was my assumption) or mounted more outboard from the body/frame area.

 

We can absolutely help. Just as an fyi, you can fit 35 inch tires without much modding. So 34s should not be an issue. The main issue for fitment is usually because people want wider tires and wheel offset to the outside to get that flush look or sticking out look. The aftermarket wheels and spacers create issues for taller tires especially if wider tires are fitted. Tall skinny wheels on stock offset will fit with less fuss. The major issue for fitment is in front of the front wheels at the bumper and aux coolers. There are products to relocate the coolers and with a bit of plastic trimming, fitment of 34s should be no issue. If on coils, we suggest our 2 inch lift kit (static height helps with larger tire fitment and ride quality) . Air is as simple as lift rods or a fancy tool to calibrate. Keep in mind , ride quality of air suspension goes down when lift rods or adjustments are done. Most people say it is minor up to 1.5 inches, but over that it gets stiff.

 

It seems like they added the spacing in the carrier knuckles. Those are unique different part numbers and can be cast to add track width. Also the wheels are the same offset, but are .5 inches wider than a stock wheel, so if the width changes with the same offset, the backspacing changes and the wheel sticks out more.

The subframes are the same as all production models so the mounting location of the suspension arms is not changed. The arm lengths are not changed especially the rear since the lower control arms are all the same. Track width is 2.7 inches wider as per Internet info, so 1.35 inches wider on each corner. My guess is that the knuckle has about 1 inch more width built into the casting and since the acles are different part numbers, the axles are likely about an inch longer to make up for the knucles being out further. The longer axle would allow for more axle travel.