Airing Down Tires
Thread Starter
|
Recovery Vehicle
Joined: Oct 2018
Posts: 943
Likes: 309
From: Colorado
Airing Down Tires
I had an LR3 for 12 years and took it off road on true 4 wheel drive trails in the San Juan Mountains, Colorado a number of times.
I replaced it with a D5 that seemed just as capable but I never felt like it belonged on those same trails. This was just my feeling, not backed by fact. It has off road tires and a 1.5 inch lift.
Recently on those same trails, I decided to air down my tires to 30 psi instead of the 44 front/50 rear I always run. The differnce was incredible.
With the air suspension I never minded the higher pressures but I wanted to see the difference with the lower pressure and would never take it on those trails again without the lower pressure. I never had trouble with traction at the higher pressure but the comfort level sure improved. Previously, when it was in raised/lifted mode, I would get some rebound banging over the rocks. I did not get this same rebound in reglular/normal air suspension mode. Only with the higher air shock pressure.
With the lower pressure that was nonexistant.
I had always felt that this vehicle could go almost anywhere without lowering the tire pressure (nor using any terrain modes other than low range) so I never bothered airing down the tires.
I replaced it with a D5 that seemed just as capable but I never felt like it belonged on those same trails. This was just my feeling, not backed by fact. It has off road tires and a 1.5 inch lift.
Recently on those same trails, I decided to air down my tires to 30 psi instead of the 44 front/50 rear I always run. The differnce was incredible.
With the air suspension I never minded the higher pressures but I wanted to see the difference with the lower pressure and would never take it on those trails again without the lower pressure. I never had trouble with traction at the higher pressure but the comfort level sure improved. Previously, when it was in raised/lifted mode, I would get some rebound banging over the rocks. I did not get this same rebound in reglular/normal air suspension mode. Only with the higher air shock pressure.
With the lower pressure that was nonexistant.
I had always felt that this vehicle could go almost anywhere without lowering the tire pressure (nor using any terrain modes other than low range) so I never bothered airing down the tires.
Last edited by ponderosajack; Oct 21, 2024 at 09:25 PM.
Mudding
Joined: Nov 2021
Posts: 213
Likes: 131
From: Southern CA
i recall reading a giant defender forum thread about this topic; it had a post from a (claimed) LR employee.
Apparently, JLR recommends airing down 18" or smaller wheels. 19"+ are recommended to try "comfort" spec air pressures as a baseline, and tweak as needed.
Apparently, JLR recommends airing down 18" or smaller wheels. 19"+ are recommended to try "comfort" spec air pressures as a baseline, and tweak as needed.
Mudding
Joined: Nov 2021
Posts: 213
Likes: 131
From: Southern CA
I'm quite late to this thread I'm afraid, but I feel it's important to address this topic. At JLR it was very painful for us to watch the TFL video in which they experienced multiple flat tyres on the trail with their new Defender. The video received many views and misled perhaps millions about our vehicle. The tyres on that vehicle were NOT running the appropriate pressure and thus easily pinch-flatted on a rock.
I can't emphasize enough that you DO NOT lower the pressure on low-profile tyres. Period. You need sufficient sidewall height to do this and low-profile tyres do not possess this sidewall height. I define low profile tyres on an SUV as anything with less than 7" (180mm) of sidewall height. You can manipulate pressures and go below factory pressures with 18" wheels, but the 19-22" wheels should stick to comfort settings. 2.2 Bar/32psi is the bare minimum, but you'd be safer at 2.3Bar/34psi.
More importantly, there is very little to be gained on a low profile tyre by doing this. Traction is a function of surface area, vehicle weight, compound, tread, etc. I can assure you that our terrain response systems are calibrated to deal with the tyres at factory recommended pressures.
When you see press videos or films of our vehicles flying across deserts or climbing through remote parts of the African continent- I can assure you we are not running low pressure.
I can't emphasize enough that you DO NOT lower the pressure on low-profile tyres. Period. You need sufficient sidewall height to do this and low-profile tyres do not possess this sidewall height. I define low profile tyres on an SUV as anything with less than 7" (180mm) of sidewall height. You can manipulate pressures and go below factory pressures with 18" wheels, but the 19-22" wheels should stick to comfort settings. 2.2 Bar/32psi is the bare minimum, but you'd be safer at 2.3Bar/34psi.
More importantly, there is very little to be gained on a low profile tyre by doing this. Traction is a function of surface area, vehicle weight, compound, tread, etc. I can assure you that our terrain response systems are calibrated to deal with the tyres at factory recommended pressures.
When you see press videos or films of our vehicles flying across deserts or climbing through remote parts of the African continent- I can assure you we are not running low pressure.
4wd Low
Joined: Dec 2023
Posts: 12
Likes: 7
We have 275/55 R20 Nitto Recon Grapplers and when we off-road (desert and rock climbing) we air down to 20psi. Much more comfortable ride and better tire grip. That being said, we also carry a full size off-road spare.
5th Gear
Joined: Feb 2026
Posts: 5
Likes: 1
Recently put BMW X5 18" wheels with 265/65R18 tires. Biggest surprise was the in town mpg boost vs the stock HSE Luxury 22" and Toyo Proxes STIII tires that were 285/40r22. Plus the weight alone was a huge difference. Felt like at least 40lbs/ea. Highway it's only maybe 1-2 mpg better. But in town was easily 3-4 more. I'm closer to 25 in town and 31-32 highway. This is the td6. Also so far only tested on sugar sand but much better grip aired down to 25 front 29 rear.
5th Gear
Joined: Feb 2026
Posts: 5
Likes: 1
X5 isn't far off from the d5 weight wise. Some x5 also have 3rd row. According to wheel spec 725-750kg for this particular style. Close enough for me. Either way it's 100x better than the stupid fancy factory Luxury wheels it came with that are useless off-road. In that regard I trust my current setup way way more than the original 🤣🤣🤣
