So I searched and searched for a way to get anything smaller than a 19" rim on my Supercharged Sport (07), and finally my local offroad wheel & tyre ledgend found some for me. After about 101 visits to rim shops who think they all have the answers.. Until they see the size of the rotors & calipers of course..!!

The mods were somewhat intricate, because anyone who has Brembo brakes on their Sport will know about the damn little blocks attached to the inside of the Brembos.

Solution, have new blocks made up out of cast steel, but so they are a different shape and become flush with the calipers. Make them the same cubic milimeters & weight as the original blocks, but a different shape of course so the rim actually fits around them.

I talked to a lot of people about what these little suckers are (blocks attached to the calipers), and I finally got some answers (albiet vague). They are apparently there to stop caliper vibration. I was told that if you take the blocks off, and then get some caliper vibration, then your ABS, traction control etc. will dissengage. I actually found that when you get caliper vibration the ABS actually engages... (opposite of what I was told, but makes more sense I suppose... brakes shudder, car thinks you are braking really hard, ABS engages...) That was with the blocks OFF mind you...

So, just a small message in celebration of my recent achievement, and I will post photos, specs, and videos of the result (me celebrating my new found real off-road & sand capability). Anyone who wants a quick summary before I get my act together with video and pics, let me know.

The end result is that I am now running 255, 55, 18" Coopers on my 18" rims, PLUS my Rangie is Supercharged with Brembos... A combination/solution I have looked everywhere on this forum for, but to no avail...

Here's a vid - although you can't see the wheels and tyres, I'm sure you can see the result of them! Try to do that on 20" rims in an SC in deep sand, impossibile. Believe me, I tried...




Enjoy the deep sand rally track! I did... (at very stupid speeds mind you...) The car is actually sideways most of the time there, stradling up out of the ruts.. you just can't really tell on the video..

Ciao!

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Yeah, too slow to get my will written in time... pretty scary when you are going sideways and trees are skating towards you

Oh, and the music, I definately recomend listening to Mozart or something when you have a 4.2l cat under your bonnett

As for Rolf Harris, he could have been in the back smashing me over the head with his guitar & I wouldn't have noticed..!

ROFLHARRIS

Looks like a quiet amble on a picnic trip Still, I suppose with those little wheels the speedo made you think you were going fast

The rolling circumference is the same as the original 20"s, so the speedo is the same.. good point though..

Reason I wanted smaller rims is for more tyre profile, so the tyres can belly out with pressures down on the sand.

Generally don't look at the speedo anyway, just judge your speed based on your heart rate - more accurate that way..

Ok, spill the beans! A few of us over in the US have been dying to find a way to get 18"s around our Brembos. The main difficulty has been finding the right wheel. Post up the details of what wheel you are running, and whatever specifics you have on modifying the calipers. Thanks, we sure appreciate it!

Ok, here’s a slap happy explanation of the specs and details involved in putting 18” rims on a RRS S/C (only.. i.e. if you have the factory front Brembo’s)

Bear with me, as I will edit and update as more precise details come through regarding offsets for wheels etc.

1. STEP 1 – CALIPER BLOCKS (vibration dampeners)

When you take a front wheel off, and poke your head into wheel well to see the “car side” of the calipers, you will see 2 blocks pointing to the back of the car, that are attached to the calipers themselves.

They look like they do nothing, and they come off very easily with an allen key. But Land Rover tells me plainly “don’t take them off” with their usual blank look on their faces, not knowing why they are telling me. Standard cautious advice I suppose.

After a while I finally talked to a few different service departments who say the blocks are to stop caliper vibration, which makes sense in that they dampen any vibration that the caliper might experience.

My solution, make some up like this:



What I tried to do is get the dimensions of the original blocks, work out the cubic millimeters in the existing blocks, and then make them with a slant on one side so that the rim will actually fit around them whilst still being bolted back onto the caliper. I.e. make the blocks deeper (i.e. towards the suspension, there is heaps of room), but make them look “cut off on an angle”.

I won’t give you the dimensions of the blocks I made, because I stuffed it up anyway, plus I wrongly had them machined from alloy instead of cast so they were like half the weight. Didn’t experience any problems though, and I think it’s more that there is “something” there to dampen the vibration, rather than the exact measurements/size etc.

What I would try to suggest is to match the weight of the new blocks with the original blocks, whilst making them into a shape that the angle of the block follows as flush as possible with the caliper if you look at it installed from the side of the car.

Get your blocks made, and get your blocks on! Step 1 complete! P.S. Whenever I change to my off-road wheels I put the angled blocks on, and when I put the 20”s back on I put the original blocks back on, because I still don’t trust myself with the new blocks. I’m just over cautious I think (probably just because of what the guy who made the blocks looked like..!!).


2. STEP 2 – ADVANTI RIMS

The specs for the Advanti rims are as follows (if information is missing, I will get update the post when the info is received by me, I have to retrospectively get some info because what we tried just “worked”)

Here's mine:



BRAND: ADVANTI http://www.mrmag.com.au/catalog/item.asp?id=447
NAME: PHOTON
SPECS: 18” x 8”
LOAD RATING: ???????
SPEED RATING: ???????
OFFSETS: ???????

This is what the offset configuration looks like:



The rim supplier simply looked up the offsets for a RRS S/C (07) and he apparently had the published offset information to go off. He then used a blank rim, drilled the center core, and machined the offsets to the published information. Any good wheel place should be able to get that information, but I will chase it up to put in the summary above. There may well be another brand of rim that fits the right criteria of this rim, but to tell you the truth after all of my running around asking people who didn’t know what they were talking about I am more than happy with this one.

I am having the rims sand blasted, and powder coated matte black soon, so I will keep the post up to date with that. I may have to paint (instead of powder coat) them if the alloy isn’t ok to put into 200+ degrees Celsius.


3. STEP 3 – TIRE FITMENT

What I wanted to do is stay as close as possible to the rolling circumference as the standard, which I believe to be something like 726 (cant remember exactly, but I’m pretty certain that’s it for the 20” Conti’s. The tires below have I think a rolling circumference of 734 or something like that..

I am running the following tires (these aren't my rims obviously though):



NAME: COOPER H/T Plus
SPECS: 255 x 55 x 18 (The Specs for the tire are here: http://www.coopertire.com/html/products/sp...guageId=1)

The 3 reasons I got this tire are as follows:

1. The rolling circumference is the most similar to the standard 20”s rolling circumference.

2. They aren’t too mud terrain etc. for example, if I don’t feel like changing my wheels back the day I return from an off-road trip I can still drive around on them on the road with not too slushy handeling..

3. That type of tread pattern is better for sand than some of the chunky mud terrain stuff you can get through Mickey Thompson etc.


IF ANYONE PUTS A TIRE MORE THAN 55 PROFILE (i.e. more tyre wall than the specs above) ON THEIR RRS S/C (in 18”) AND DOESN”T HAVE A PROBLEM, PLEASE LET ME KNOW, BECAUSE I ONLY TRIED TO KEEP THE SAME CIRCUMFERENCE OUT OF CAUTION RATHER THAN CHOICE. You will have to beware of tires scraping on the wheel well and whether the computers start playing up with any crazy rolling circumference. I wasn’t game to do that, I was just happy enough to find a solution full stop..


Let me know what you think so far, and if you have any questions let me know. Can’t think if I’ve missed anything.

By the way, the above is not advice, it’s just what I’ve done… Make any decisions at your own risk, I don’t have to tell you that brakes are an integral part of your car… I accept no responsibility for anyone else’s decisions (or damage to car or person) other than my own… [/img][/img][/img]

Last edited by andrewjakovac on Thu May 10 2007 9:25am. Edited 6 times in total

Uploading images

http://www.rrsport.co.uk/forum/topic30.htm...ing+photos 2005 Zambezi TDV6 - Gone but not forgotten
2009 Alaska TDV8 - Gone and much missed.



WINNER - 2009 �Idler Of The Year� Award
Runner Up - 2009 �Just Doing What It�s Designed To Do� Award


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Thanks for that info about uploading images...

Post updated with a bit of text and image addition. Will keep posted on the offset info & load rating info I get back from my wheel man...

By the way - www.fourbys.com.au is THE place to go for the wheel & tyre set-up explained in this post... Can't say anything better about those guys, can't fault them..

Cheers.

Hope the information has helped so far..

I'm still waiting for the information on the offsets though, and the reason I want to put it out there is because I am sure there are other load rated rims out there with the same specs etc. that could fit, so the numbers would be good to have...

andrewjakovac wrote:

Hope the information has helped so far..

Definitely, thanks for posting.

You should be able to go a bit bigger than 255/55-18, however your truck will seem a bit slower and your speedo will be pessimistic. Apparently you can go all the way up to a 285/60-18. Check it out:
http://www.rangerovers.net/outfitting/tires/sporttires.html

Did you ever try an LR3 18" wheel like this:

Those would make a conversion super easy since the offset and bolt pattern are already machined correctly.

Regardless, be sure to post the offset information when you find out.

Did you consider just removing those little caliper 'vibration damping' blocks altogether? From my relatively layman perspective, it seems that LR underengineers some parts of the truck. They then compensate by adding weight, or 'balancers'. For example, the swinging concrete blocks just inside the rear bumper. As if the truck needed to be ever MORE obese!
Maybe you could get away with removing those balancers altogether...

Hi Drevs,

Thanks for the insight. Couple of problems / questions though:

1. Have you tried using the standard LR3 wheel on the Supercharged? I notice the one in the photos is a back wheel (i.e. no Brembo brakes)..

2. I tried to get the LR service workshop to try and fit some of the standard 18" RR Sport (non supercharged) rims on mine, and they didn't fit around the Brembos... I must admit that I am not sure whether they tried with removing the dampeners or not.. I suspect not.. But it would most probably mean that the standard LR3 18" rims don't fit around the Brembos.. If someone can try standard RR Sport 18"s OR LR3 18"s for sure, that would be great - let us know (so I can cry for all my wasted hunting for alternate rims...)

3. Since I already have the dampeners made up with the "cut off configuration", I'll always leave them on and not risk driving without them on. But you might be right and you may be able to successfully drive without them on... I just wouldn't recomend it given that LR raised their eyebrows so high and scared me heaps by saying the words "brakes are a very integeral part of the safety of your car..." I tend to agree with them in the main... Plus, i did try it without the dampeners for a bit, and the ABS did come on more often than normal (in fact whilst cornering, not braking...) I suppose that's a sign to leave them on, especially the way I kill my car in corners when I have the 20"s on...!!

The site you sent me did upset me a little bit because I was trying to do the right thing with the rolling diameter and keep mine as close to the standard RD as possibile... It seems as though you can increase it substantially without causing dramas with the electronic systems... Damn me for being cautious with my $140,000 vehicile.. Wish I wasn't though..!! One main reason for being so cautions was because they told me that there is a speed sensor in the transmission, PLUS speed sensors at the wheels.. Therefore they didn't know (nor recomend) whether there would be computer faults / shutdowns when the two speed sensors contain different readings from eachother... they speculatively thought there MIGHT be issues with some electronic systems (i.e. traction control, ABS, and any speed related gizmos)...

Let me know... and thanks again for the feedback..

I have not tried an LR3 wheel... just a thought.

I'll have to drive around a bit and see what happens with the caliper blocks removed.

Right now I'm torn between going through the same 18" hassle you did, or just putting some offroad style tires on my extra 20's. The Cooper Zeon LTZ is a cool tire that one of us USA people just installed. I'm looking at testing out a set of the 285/50-20 and seeing how they fit. Here's the thread on the other board:
http://rangerovers.net/forum/viewtopic.php?p=113392#113392

Since I already have a set of wheels/tires for the street, I'd really like to get some serious mud terrain tires for my dedicated off-road setup. Unfortunately I can't seem to find a really aggressive tire in either 18" or 20".