Thread: Sidewall strength in a 20"

LT275/55R20 in BFG KO2 are way to noisy on my MY12 for which I have applied sound deadening stick-on material to every accessible panel at the front including the inside of the front guards and all flat sections behind the front liners and outer foot-wells, the spare wheel well, the channels underneath and the air reservoir but still can't stop the resonance.

The availability in Australia of the Pirelli All Terrain Plus in 275/55R20 with LI 113 and an improved strength carcass for off-road use over the earlier ATR with its LI 110 has been put back to 4th qtr from its earlier Aug/Sept date. I hope that my KO2s will last because the AT+ are reportedly very quiet yet have a reasonably open tread pattern with full depth voids right across rather than the part depth commonly seen.

I would prefer to fit 255/60R19 on D4 rims to lower the gearing on this already highly-geared vehicle but currently that size in the AT+ has not been released anywhere. However 8 more sizes are reportedly scheduled for release in the 3rd qtr and with all 17/18/19 30" LR sizes already available perhaps D5/L494/L405 31" sizes might be included, noting that the 90% highway-use Pirelli Verde All-Season is available in 255/60R19 with LI 113 for these later vehicles. I may have fit the 20" version this time then change to 19" next time as I expect that my preferred 19" will eventually be produced even if not in this next release.

Originally Posted by justinc

Tyres... 🙂😅

Looking at trying a slightly taller tyre such as a 275 55 20 to enable some aired down use and gravel road etc, and after some experienced recommendations from real world users of this rim size.

Currently thinking of Mickey T Deegan 38 A/T, BFG KO A/T and Toyo Open Country.. which i think only do 275 50 20.

Jc

I ran 265 50 20 and thought they were quite good in my few excursions off road, I had no problems.

I'm looking at 275 55 20 for my RRS as well, I have decided that the BFGs would be too noisy and I don't need such an open tyre anyway. The Mickey Ts look interesting and there is also the GoodYear Wrangler Duratrac. If you look at XL tyres rather than LT there are a few such as the Nitto Terra Grappler and Nexen Roadian AT Pro as well.

You could also consider 285 50 20 if they will fit as there is a wide range of those as well.

Graeme, will the 19s fit over your Brembos? I thought that 20" was the minimum for the L322?

A special RR 19" was produced to fit over the 6-pot Brembos on the L322 but D4 19" rims fit too. I transferred my D4's rims to the L322 for a few weeks to get a better ride than the 255/50/R20 on the L322. D4 rims have a slightly less positive offset (53mm vs 57mm) which is of no real significance.

Edit: I recently refitted the 19" D4 rims for a test run and appreciated the lack of noise and the original gearing even though not towing but the stones on gravel roads and bumps on sealed roads were noticed a lot more than with the BFGs.

Graeme is that any style of D4 19"? I would be interested for sure as there is a nice quiet Hankook A/T in 255 55 19 that is appealing

Hankook_RF10.jpg
These were from my MY10 3.0 D4 but I expect that any D4 19" rim that fits a 3.0 will fit. These had proper minimum clearance.

With the 6 spot cslipers or was that the ones where you changed to 5 litre brakes?

And how do you rate the Hankooks? These are the ones i am interested in..

I haven't changed the brakes and hope to avoid doing so.

I only used the then new Hankooks for a few weeks so don't have much experience with them - my son Justin who now has the D4 ran the tyres until a couple of months ago. They're like all 255/55R19 without much sidewall height and like most the sidewalls are light-weight but they weren't noisy when refitted some weeks ago for a trial even though well worn. However I'd give the new Pirelli All Terrain Plus in 255/55R19 a try if fitting this size, which is an option being considered as the 275/55R20 might be too long coming.

PS. I may have been unduly critical of the noise from the BFGs, having spotted the rears are quite scalloped on the outside blocks and recalled that the rear hasn't had a wheel alignment since fitting the e-diff over a year ago which required the top adjusting bolts to be R&R'd.