Rim offset

[83zook]

Hi i am looking at getting some 15x7 sunraysia's, i am looking for rims which have between 2" and 2.5" backspacing. If anyone has 4 or 5 for sale or know where i can buy some it would be greatly appreciated.
Also if anyone has a cheap set of 30 to 31" muddies also PM me.
Thanks
Mitch

[built4thrashing]

will be easier to find 15x8 f100 rims with the offset your after.

31 tyres still fit ok and gives a meaner stance.

[83zook]

thanks b4t but wouldn't the 15x8's rub on the springs and make it harder to steer? i guess if the rims had the right offset they wouldn't. im after a bit more track width to make it more stable, unlike yours i guess being a narrow track will make mine feel unsafe on side angles, etc than yours.
BTW I have been experiencing really bad bump-steer in my zook, what do you think the best cure for this is? RTC dampener, or a dropped pitman arm? at the moment the RTC is looking good in comparison, costwise.
Mitch

[want33s]

thanks b4t but wouldn't the 15x8's rub on the springs and make it harder to steer? i guess if the rims had the right offset they wouldn't. im after a bit more track width to make it more stable, unlike yours i guess being a narrow track will make mine feel unsafe on side angles, etc than yours.
BTW I have been experiencing really bad bump-steer in my zook, what do you think the best cure for this is? RTC dampener, or a dropped pitman arm? at the moment the RTC is looking good in comparison, costwise.
Mitch

I just bought a set of 15x8's (33x10.5R15)to replace 15x7's(31x10.5R15) on my Sierra. Backspacing is exactly the same. 80mm from memory. Just an extra inch wider outwards.
Wider rims won't make it harder to steer but wider tyres will. Wider tyres will also increase your turning circle.
The more offset you have the higher the load on the bearings.
As for bump steer, start with a wheel alignment and go from there. I put a RTC damper on mine and it didn't make much difference at all. I only have 2" spring lift, no SOA.

[lay80n]

thanks b4t but wouldn't the 15x8's rub on the springs and make it harder to steer? i guess if the rims had the right offset they wouldn't. im after a bit more track width to make it more stable, unlike yours i guess being a narrow track will make mine feel unsafe on side angles, etc than yours.
BTW I have been experiencing really bad bump-steer in my zook, what do you think the best cure for this is? RTC dampener, or a dropped pitman arm? at the moment the RTC is looking good in comparison, costwise.
Mitch

I just bought a set of 15x8's (33x10.5R15)to replace 15x7's(31x10.5R15) on my Sierra. Backspacing is exactly the same. 80mm from memory. Just an extra inch wider outwards.
Wider rims won't make it harder to steer but wider tyres will. Wider tyres will also increase your turning circle.
The more offset you have the higher the load on the bearings.
As for bump steer, start with a wheel alignment and go from there. I put a RTC damper on mine and it didn't make much difference at all. I only have 2" spring lift, no SOA.

The more offset you have, the larger your scrub radius is, and the more effort to turn and more scrubbing of the tyre will ocour. Basically, if you draw a line through the centre of your upper and lower kingpin, it should hit the ground at the centre of the tyres contact patch. Increasein the offset without increasing the tyre sidewall height sufficently increases the scrub radius. Correct that the increase in offset will load bearing. Bump steer is due to the opperating angle of the drag link, not the wheel alignment. If the alignment is causeing it, its not bump steer. When teh drag link travels through its arc, its effective length between the pitman arm and the link to the tie-rod changes. This shortening and lengthening of the effective length is what causes bump steer. Keeping your drag link parallel to the ground, or paralell to the panhard rod in linked applications is the way to eliminate or at least reduce bump steer. Steering dampeners are a band-aid fix.

Layto....

[dank]

went from 15x7 ROH Trak 2 with 30x9.5 Muddies to Unknown Brand 15x8 -30 offset with 31x10.5 silverstone extremes. Tyres used to Rub on full lock with the 15x7s but don't even come close with the 15x8s and 1 inch wider tyres. On a WT Sierra.

[83zook]

Thanks for all your input, Dank do you know if they will rub on a narrow-track? also did you need a bodylift for 31's? I have at the moment 2" spring and about 1" shackle, do you think 31's will fit? i know i'll have to make a new front bar as my 29" tyres on 15x6 sunnies rub on the bumper bracket/pipe on full compression! but not on the springs. I am going to put lj50 centres in to get the gearing as i have a 1ltr.
Also what do you think of sumitomo sarengetti M/T? as thats what im going to get. As the price is right ($167.50 a tyre).
Thanks
Mitch

[mrRocky]

2" wheel spacers

[dank]

g'day 83 zook,

look I guess you'd have to just try it out and see. I've got the OME dakar 2inch susp kits and my shackles are 2 inchs longer than standard giving me 3inchs inch of lift and a lot more articulation in the springs. the 140mm track increase is Crazy! it makes the zook look tougher and actually is a shite load more stable now than it was before.

I have taken to the bumper mounts with the grinder and rounded them off to the bar that comes out of the chassis. I've also got 1 inch bumpstops but I think I might need a little bit more maybe 5-10mm. I also cut off about 15mm off my outer WT guards to minimise rubbing and tek screwed in bunnings poly garden edging.

here's mine....84 zooksta is the ugly bugger walking next to my zook!


I dont' have a body lift at the moment and am reluctant to do it due to the COG changes that occur. I can live with a tiny bit of rubbing.

Also i'm thinking of cutting more out of the outrigger bar tha holds my winch bar on at an angle to give it more space and just weld in a section of plate on an angle. I don't want to completely cut them off as it provides really good mounting points for the wonch bar which can winch out something like rochrd's lwb patrol beast when it needs to.

I had other ideas of cutting off the mounts and sleeving the cross member and then welding on new outer mounts for the bar but at this stage I don't think I'll change it. I might cut off some more tube and weld in some plate and see how i go.

as for your tyre dilemmas I would highly recommend something like the federal mud terrains that widetread in ferntree gully have in 31s at around 165 a tyre. New pattern way more agressive than sumitomo(these will wear out in 20000k), hankooks and BFGs....I haven't actually tried the federals but they look really good for something like a zook. Also Kuhmo make a nice agressive Mud terrain as well for aorund 175 a tyre worth checking out as well. Stay away from the Sumitomos! I'd say in a narrow track you would need at least a 2inch bodylift to fit 31s. got nuts with a hammer and grinder!

One guy that came out with the zook club to toolangi on the only zook club trip I did had just put in a 3 inch body lift and 31x10.5 mongrels and he was packing his dacks at the COG increase on the high angled tracks. whereas I felt pretty comfortable on the same tracks in mine.

PM suzuki boy. He has 30x9.5s on his. Also 84ZOOKSTA has 32x10.5s on offset 15x7s, 3 inch bodylift and flat springs...really good setup and it goes hard although he has 6.1 or 6.4 tranny gears.

Speak to Dave at Lindsays Tyres in Mt Evelyn, he sorted an awesome deal out for me on my 15x8s and the silverstones.

good luck....what a mega post!

[mick85]

just be careful with the f100 rims, earlier f100 had smaller hub than a suzi and as someone told me not too long ago it wont fit over the hub!!

found out the hard way when searching for a spare, the centre hole needs to be about 11.5cm or so and early early f100 rims had a centre hole of about 8ish cm... but some do fit, otherwise roh do a steelie called trak 2

just a thought,

mick

[Gwagensteve]

I agree Dank- Those Federal muddies look the business- surprisingly aggressive.

The guy with the 3" BL was also NT and had stock offset rims - I agree it was pretty spooky.

If you don't have clearance problems with your current setup, there is no need to go to a BL- they don't really have any useful effect except for tyre clearance

In itself, I don't think BL's have too much effect on COG. Part of the problem is 1/2 built cars that are way too narrow with BL's. Obviously, BL's have less effect on COG than a suspension lift of the same height.

83Zook- Yes, 31's will rub on a NT with almost any amount of suspension lift. It's confusing, but have a read of the WT vs NT discussion thread.

The long and the short of it is that 30's are an easy fit on a NT but to step up to a 31, a Body lift and offset rims are required. These two factors are irrespective of suspension height.

Wheel spacers are a very expensive way of getting 2" more track. Add to this that they are totally illegal, result in twice the lug nuts to come loose (and they do) and add substantial weight where you least want it.

A wheel repairer will change the offset on steel rims for $35-$50 per rim.

2WD F100s have the small bore centre.

Steve.

[bigzuk]

i found it much easier to go out and buy new rims when i wanted some decent offset. for the 55 bux a rim i paid for my 15x8's its alot less screwing around than chasing 2nd hand f100 rims.

[lay80n]

I run my swampers on Speedy Rims Desert Rats style 15x8 sunrasia style rims with -28mm offset. Give a good offset, and cheap as chips. If you need more offset, look at getting your rims flipped as Steve said. Wheel spacers are expensive, offer more studs (that WILL come loose) and are illegal.

Layto....