Thread: 275/55R20 KO2 or LTZ

Whilst the original bad resonance was resolved by refitting the brake-line spacer to keep the pipes apart, there's been a continuing light howl from very low speeds up to and including 100 kph on any surface, but non-existent at 110. After a 4 hr trip this morning I was moved to fit sound deadening to the inside of the RF guard and to the hollow panel behind it, as the front guards resonate when tapped whereas the doors do not. With the bonnet up and one hand along the top edge of the guard between bolts, the guard edge vibrated when the flat of the guard was tapped. It may be a day or 2 before a proper test is done to learn if there's any improvement. Forever hopeful!

Edit: Although only a test distance of 4 kms of sealed surface, the noise now sounds to be coming from the left front of the cabin whereas previously it was predominately from my right but also from somewhere else in the cabin. The left front guard is next!

Another edit: Even more promising was finding that the body box section that runs along the top of the guard and to which the guard mounts, when tapped with fingers, resonates like a drum at about the same frequency as that of the noise that has been driving me to distraction. I had applied deadening material to the right side's box section but covered the left one as much as possible, as well as with the guard itself. I'll find out tomorrow the success or otherwise of the exercise.

In my final attempt to reduce the cabin noise from these tyres, the inner sides of the main front to rear rails have now been treated with patches of vibration damping mat as their several sections resonated at different frequencies when tapped. The outer sides and half the bottom was treated at build time with a spray-on material, but not the inner sides. On the left side some adjoining resonating panels below the floor were also treated but the equivalent floor panels on the right could not be done due to the need to drop the exhaust system to totally remove the heat shield to gain access above the right catalytic converter. However one 30cm long section of under-floor panel readily rattled/vibrated when poked with a long screw-driver, suggesting that the opposite, hidden edge missed being welded during assembly. That panel has now been sufficiently distorted to stop it rattling by jacking the screw-driver.

Tomorrow I'll find out if this last attempt has succeeded.

20170314_121200.jpg

What is everyone using for tyres now?
Anyone using a good ATR that handles better than the KO2 on the Rd?
Maybe Pirelli Scorpion ATRs?

Whilst I have no complaints with the KO2 handling on any surface, I have a set of Pirelli All Terrain Plus that will be fitted early next year. The AT+ tread is as open as the KO2, is as wide for sidewall protection, has almost the same load rating (113 vs 115) and importantly for me is reportedly almost HT quietness on sealed roads. However it is a passenger tyre rather than LT which is expected to provide a less harsh ride and hopefully will be strong enough. The sidewalls aren't as thick as the KO2s but are quite substantial for a P-rated tyre.

Originally Posted by Graeme

Whilst I have no complaints with the KO2 handling on any surface, I have a set of Pirelli All Terrain Plus that will be fitted early next year. The AT+ tread is as open as the KO2, is as wide for sidewall protection, has almost the same load rating (113 vs 115) and importantly for me is reportedly almost HT quietness on sealed roads. However it is a passenger tyre rather than LT which is expected to provide a less harsh ride and hopefully will be strong enough. The sidewalls aren't as thick as the KO2s but are quite substantial for a P-rated tyre.

Thanks Graeme,
Are those AT+ readily available here in Australia?

Ok I just found them online. 275/55R20 113T.
Does anyone know how they compare for actual size compared to the KO2?
Assuming similar rub.

Here's a pic of the 2. I'll be keeping the 2 half-worn KO2 as spares.
The 1st AU shipment arrived a few weeks ago so I grabbed 4 in case none in stock when I needed them.

Cool.
I’m curious how much quieter they are on bitumen and if they have better road handling than the KO2’s