suspension and tyres

[Abri Hoffman]

Abri
What was your rationale for this move to narrower tyres?

Apparently the narrower tyres has less drag. My main consideration however was price as at the time the 255's were R400 per tyre less than the 285's. The 255's are about 7.5mm higher than the 285's thus nothing sacrificed in terms of ground clearance while flotation is as good.

Cant say I notice any difference in terms of power of fuel consumption.

The Maxxi's are holding up very well. Sidewall does not grip as good as the BFG's and they are much noisier than the KM2's.

[Jorrie]

Abri, thanks.

[Zantus]

Here's some pics of my Patrol with half worn 315/75R16 Bighorns with standard suspension, but the mudflaps have been removed.

It rubs on the control arm when turning right but not to the left, guessing the steering stops aren't adjusted the same. Then they rub at the back, but not too bad, these marks are from gunning it up some steep loose hills with cross axles.

I'll gladly take this set-up on a slow moving trail, but I won't go racing up dunes just yet, bottoming out hard, might damage something.

Time will tell what the gearing will be like, only done about 50km's of flat roads, but I made up my mind a while back, that I want tyres that are 35" tall and if gearing is a problem, I'll do a ratio change and not revert back to smaller tyres.

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[Jorrie]

Zantus, dankie vir jou inset. Ek hou van die groooot tyre image, maar ek dink ek gaan hou by die 285/75/R16 bande!

[Sweetlips]

Jorrie daai 285's is dit die selfde as 33"?

[Tinus lotz]

Dit werk so die 285 is die wydste gedeelte van die band die 70 of 75 is n persintasie van die loopvlak vir die sidewall en ja 285 75 16 werk uit op 33 duim deursnee
Zantus daai 4.5 lyk baie mooi met daai tekkies, ga jy n lift kit opsit????

[ChristoSlang]

Use the following formula to determine the height of the rubber in inches: (<Section width in mm> / 25.4) x (<Aspect ratio> / 100), multiply it by two (for the top and bottom portions of the tyre) and add the rim height to get the total height of the tyre. For a 285/75/16 this means:

(2 x (285/25.4) x (75/100)) + 16
= 2 x 11.22 x 0.75
= 32.83

So naby as demmit aan vloek van 33" af

Zantus se 315/75R16 werk uit op 34.6"....

[Zantus]

Working out the theoretical tyres size is all fine, but remember to check the specific tyre's actual size because tyres are not all made at the exact theoretical size. The Kumho KL71 33x12.5R15 tyre stands out in my mind in this regards, because that tyre is actually only 32.3".

My tyres have an actual size of 34.6" as well, but at least half of the 15mm tread is gone (7mm per side), so that takes mine down to 34" at the moment.

Just looking at the Maxxis Bighorn 285/75R16, because I have that website open, and it's true size is exactly 33".

[Peter Connan]

Zantus, a set of spacers (or rims with more offset) will solve the rubbing inside the rear arches as well as on the front control arm, but could cause problems with the front mudflaps (or you could just adjust the steering stop).

Sweetlips, in general, as far as lifting a Troll goes:

Up to 3", you can get away with just caster-correction bushes and ideally a lower gearbox mount (comes with the better kits), brake bias fix and anti-sway bar extensions as described by Christo, although I would probably either just remove the anti-sway bars altogether (if you don't use a roofrack) or fit quick-disconnects.
Over 3", you need to fit longer brake pipes and diff breathers.
Over 4", you need to fit adjustable panhard rods and drag links, and caster-correction bushes start becoming marginal. There are a couple of methods of fixing that, the easy way is to use drop-boxes.

I believe 285/75 R16s (and maybe 33" x 12.5", or 315/70 R16) will fit a GU (but not a GQ) without any lift.

[Zantus]

Zantus, a set of spacers (or rims with more offset) will solve the rubbing inside the rear arches as well as on the front control arm, but could cause problems with the front mudflaps (or you could just adjust the steering stop).

Mudflaps were removed when I got the Patrol, they are usually the first thing I rip off in sand and often a vehicle's plastic wheel arch will go along as well.

The rubbing at the front control arm has been fixed, the steering stop on the one side was missing, fitted a bolt with the same fine thread and that problem at least is gone.