Letting The Air Out

So do you air down your tyres when you go off road, a lot of folks don’t! Airing down is the best thing you can do for off-road performance, second only to running lockers in your axles. The difference between aired-up and aired-down on the trail can be staggering. So why does airing down make such a difference, people always think that by airing down you increase the width of the contact patch of the tyre, this is true but it also increases the length of the contact patch, so it puts more rubber in touch with the ground, more rubber in touch with the ground means more traction. The table below shows how the contact patch of the tyre grows as the pressure goes down.

   

 

 

Another advantage to airing down is the way the tyre will deform to follow the contours of the ground, the photo below illustrates this very well. If the tyre can conform to the obstacle it is trying to climb over the rolling resistance will be reduced, which means a lots less effort is required.

 

 

 

 

So now that we have established that airing down tyres is a good thing how low can you go? Here is an extract from JP Magazine
“Keeping-It-Low Cappa
Almost everyone I meet runs too much air pressure in their Jeep's tires both on- and off-road. Like Christian, I cringe when I see beadlocks on a Jeep where the tire barely has a sidewall bulge. The owner generally considers 25 psi aired down since he runs the max sidewall-listed pressure of 35-50 psi on the street. Not only is he prematurely wearing out his tires, but he's rattling his teeth loose and giving up a ton of off-road performance. This is even more widespread now that 16-, 17-, and even 18-inch wheels have become common on small Jeeps, whereas before these wheels and higher-pressure tires were typically only found on 3/4- and 1-ton trucks.

Running the correct tire pressure starts by picking the correct tires. Most Jeeps only need a load range C tire. The D- and E-rated tires are for heavy-hauling trucks. With a C range radial tire most Jeeps can run about 20-25 psi on the street. Most bias-ply tires can hold up a Jeep with about half that. Off-road I consider 10-12 psi a good starting point for a radial tire and I'll often go lower than that if the terrain is really soft and there are few tire hazards. On a bias-ply tire you really don't get a good traction bulge until you hit the single digits, so I'll start at around 5-10 psi and go down from there if need be. To some people these pressures sound unreasonably low, but they increase traction significantly and improve the ride as well. You can either adjust your driving style to keep the tires on the beads or step into beadlock wheels if you decide to run at the lower end of these pressures.”

On my yellow Wrangler TJ with 33x12.50x15’s without beadlocks I normally drop them down to 15psi. Many people have different opinions as to how much to air down when off roading, so find what works for you and your setup. But be sure to be careful, it must be noted that we are only talking about and recommending tyres pressures being lowered while off road and at lower speeds, NOT driving on the road or at higher speeds.

So how do you air down your tyres, if you have every tried doing it will a a match stick pushing the valve down you will know how long it can take. There are a lot of devices out there to make life easy, but the one I favour is the Rugged Ridge adjustable tyre deflators, once you have set them up to the pressure you want, you just screw them on to the valves and go have a cup of tea. Once they have finished hissing unscrew them, and you are god to go. The Rugged Ridge tyre deflators are available from FTE 4x4 Specialists Ltd.

Don’t forget that once you have aired down at the end of the day you need to pump the tyres back up.

Technorati Tags: Jeep,Wrangler,Cherokee,TJ,YJ,JK,XJ,WJ,Tyres,off-road,Rugged-Ridge,FTE 4x4 Specialists ltd,Deflators

Heavy Duty Front Ball Joint Sets For the Dana 30 /44 Axles

Fed up having to replace the knuckle ball joints on your Jeep because they just don’t seem to last, running over size tyres and off-set wheels puts a lot more strain on the knuckle ball joints. When you see what is inside the stock Jeep ball joint you will understand why they wear out so quick. The photo below shows a pair of stock ball joints stripped down.Well Synergy Suspension have the answer with there new heavy duty ball joint sets, available for the Jeep Wrangler JK, TJ/LJ, YJ, Cherokee XJ, and Grand Cherokee ZJ & WJ (Dana 30/44). Fully greasable sintered metal on bushing design.

• Designed to replace the factory ball joint that is prone to premature failure on lifted vehicles with large off-road tires
• Fully greasable sintered metal on bushing design that has high wear resistance
• Outperforms the factory ball joint assembly
• Ball joint boot is made from tear/wear resistant polyurethane
• Includes all necessary hardware for installation
• Single Set includes: (1) upper, (1) lower
• Complete Set includes: (2) upper, (2) lower
• 12 Month Unlimited-Warranty

Available from FTE 4x4 Specialists Ltd 07973 198483, who are now dealers for Synergy Suspension.

Technorati Tags: Jeep,Wrangler,Cherokee,Grand Cherokee,JK,TJ,XJ,YJ,ZJ,WJ,Off-Road,Suspension,Axle,Steering

Not All Wheel Spacers Are The Same

Recently I had a Cherokee XJ brought into me with some strange noises and even stranger handling, the ability for it to go in a straight line above 20mph was almost none existent without some serious sawing on the steering wheel! At first glance underneath nothing jumped out, the wheels did have a little bit of negative camber, but I have seen a lot worst. First point to check was the wheel hubs, but as soon as I removed the front wheels the true horror was apparent.

To push the stock wheels out to give clearance for the 31x10.50 tyres wheel spacers had been fitted, not normally a problem, if the they are the correct type and fitted correctly. But these particular spaces I have not seen fitted to vehicles since the late 70’s early 80’s. They use a screw on stud extension that is tightened onto the original hub / disc then a hollow cast spacer is slid over the extension studs and the wheels then fitted back on. They work, but are definitely not designed to be used for big tyre set-ups or off-road use.

In this instance they were dangerous, as they had not been fitted correctly, (the work had not been carried out by the current owner, he had only just taken possession of the Cherokee) as you can see from the photos the screw on extensions did not have a deep enough bore to allow them to be tighten on to the hub. So when the spacer plate was fitted it was floating, with the wheel fitted it pulled up against the hex section of stud extension so the whole loading was being placed on the five hexes, allowing the wheel to basically flex on the extension studs. This did not only cause the steering to wander, but put a lot of strain on the hubs and brakes as the discs were not clamped tight to the hubs, it caused excessive wear to the brake pads and discs which had to be changed. One hub survived the ordeal the the other was replaced.

New Rugged Ridge billet spacers were fitted. These are constructed of double anodized black extra thick 6061T6 Aluminium for long life and extra corrosion resistance. All hardware is grade 8 for extra strength. They include 10 pre-installed grade 8 wheel studs, 10 lug nuts and thread locker. So as you can see from the photos below not all wheel spacers are the same!

FTE 4x4 Specialists Ltd can supply the Rugged Ridge spacers, for more information send us an email to info@fte.co.uk

Technorati Tags: Jeep,Rugged Ridge,Off-Road,Wheel,Spacers,Handling,Wrangler,Cherokee

Wrangler Resurrection is alive and kicking

 

Back at the beginning of February I wrote a blog about an old Wrangler and a new project called “Wrangler Resurrection” well it has not been forgotten, it is just that work has got extremely busy (no complaints) so my projects get moved onto the back burner. But I have been collecting parts ready to start, the rear suspension is going to be the first item to get a makeover. The Wrangler is already fitted with a Rubicon Express long arm kit, but to upgrade the rear suspension I am going to convert it over to a triangulated upper link, and remove the rear trac-bar. This should free up the suspension giving greater articulation, I am going to use a Rock Krawler weld-on rear axle mount and brace.

 

 

The upper spring mounts are also going to be altered using the
Black Diamond's Coil Correction Kit, this will corrects the curvature of the rear spring. Meaning they can do there job more efficiently, the problem is even evident at 3" of lift height, and becomes more of an issue as lift height increases. This incorrect coil loading results in lost ride height and a diminished "too soft" spring rate.

I Another item on the rear that is going to get modified is the shock mounts, at present I am undecided with which manufacturer to go with, but the intent is to turret the shocks outboard of the chassis. This will allow for greater articulation, and I will be using a Currie Enterprise coil spring retainer kit to make sure I do not pop any springs.

As for the front suspension I would like to convert over to coil overs, as I intend to change the front axle, to a high pinion unit then this will be the time I would do the work. There are many kits on the market to do this, again I am looking at using the Rock Krawler set-up. This involves cutting off the original spring/shock mounts from the chassis and welding in complete new mounts. Part of my reason to convert over to this style of front suspension is with the front diff angled correctly, the springs are bowed a considerable amount with with a 5.5” lift. One option is to cut the spring mounts of the axle and reposition them, but that seems like the ideal time to think of an upgrade!

Another item that is getting a serious makeover is the steering linkage, as once a Wrangler TJ (or a Cherokee XJ and Grand Cherokee ZJ) is lifted more then 4” then the steering is a compromise. There are many kits on the market is you own a LHD Jeep, but for us RHD owners the market is very limited. For the pass 12 months I have been trying different configurations and I am at long last very close to an answer. My main itinerary was it should be a bolt-on set-up, with the minimum of part changes, so it could be done by an owner of a vehicle rather then having to take the vehicle to a specialist workshop. As soon as I have tested the set-up, ( I have plenty of volunteers who want to test it for me) and am happy with the results, I will be publishing it here first. So as they say watch this space.

All parts that I am using in this project are available from FTE 4x4 Specialists Ltd so if you have any questions then feel free to contact me. Also don’t forget to check out our face book page  

Technorati Tags: Jeep,Wrangler,Suspension,FTE 4x4 Specialists,Rock Krawler,Rubicon Express,Steering

May not contain all you need!

Recently I was asked if I could check over a Cherokee that had a 3” lift kit fitted, to make sure bolts were torqued correctly, and such like. Once I had the Jeep on the ramp I gave it a good look over and a couple of items came to light very quickly one was serious. As you can see from the photo the suspension is almost on full drop with hardly any steering lock, and the brake line is ready tight and pulling. As you can imagine in an off-road situation with the Jeep articulated up and full lock being put on I doubt very much that the brake line would hold. Resulting in no front brakes not an ideal position to be in. So when fitting a lift kit it is always a good idea to cycle the suspension through its full travel and check. That way the next problem I found would have come to light as well.
The second problem I found was, there were no front bumpstop extensions fitted, now this is not as serious a problem as with the brake lines, but can still end up costing money. The gap between the the axle pad and the bumpstop on the front suspension with the vehicle sitting at rest was 4.75” the length of the shock rod left showing was 4”. So before the bumpstop can do it work at full compression the shock would bottom out and would act as the bumpstop. This would eventually end up damaging the piston rod and valve, resulting in new shocks being needed.
Not all suspension kits have all the parts you require in the box so to say when fitting the lift. Just because the parts are not in the box does not mean that you do not need them. When buying a lift kit if you are not sure ask, if they recommend any other components that may be required, it could end up saving you a lot of money in the long run and giving you a reliable rig as well.
If you have questions regarding your Jeep suspension, then give me a ring at FTE 4x4 Specialists Ltd. We can always advise and point you in the right direction.

C2ZN72Q53WMV Technorati Tags: Jeep,Wrangler,Cherokee,Suspension,Shocks,Brakes,Articulation,Bumpstops,Lifts,FTE 4x4 Specialists

Time for an upgrade?

The photo below shows a UJ from a Wrangler TJ front half shaft, which was only fitted 9 months ago! The corrosion is not due to lack of maintenance, as this particular UJ is classed as maintenance free or more commonly known as sealed for life ( in this case not a very long life). On a road going vehicle that does not see any real off-road use this type of UJ could last years, I know one guy with a Cherokee XJ that has never change the UJ’s and it is 16 years old and they are still in good condition!

The reason for the premature wear & corrosion is basically the ingress of water into the cups. How does this happen so quickly? You can see the seals look in good condition! When driving to the shops or work the UJ’s heat up expanding the grease and pushing any air trapped in the cups out. This is not normally a problem, as when you park up at your destination the UJ’s cool, the grease contracts and it pulls air back into the cups. When you arrive at the off-road site you drop into low box and trundle off hitting mud holes water splashes and such like. The UJ’s are cooled down by the water hitting them and the grease inside the cups cools and contracts pulling in whatever surrounds the UJ’s. Water, a water-sand mix, water-mud mix. So starts the rapid detrition of the UJ’s, and as these are sealed unless you strip the UJ out, which is not an easy job, there is no way in which to grease the UJ and push the dirt/grit out.
There were some UJ’s that were cross drilled with a grease nipple (red arrow) but this caused an inherent weakness and they often broke across the middle (in off-road use). There are a few heavy duty UJ’s available such as CTM, but these are not designed for long road use at high speed. So what is a good alterative to the stock Spicer UJ? Alloy-USA make a UJ that fits the bill, serviceable flush grease nipples at each cap allows you to flush grime and fill with grease. Made of cold forged steel composition made of chromium, molybdenum and nickel alloy, with a hardened case for excellent wear resistance. These UJ’s are not a lot more expensive than the stock Spicer units, but if maintained will last and give years of trouble free miles.

So the next time you are stripping down the front axle to pull the half shafts to change out the UJ’s why not upgrade to a serviceable unit. Its is a lot easier to pump a bit of grease into a UJ then replace it!
For more information and prices contact Steve at FTE 4x4 Specialists Ltd. on 01268 730131/07973 198483 or email steve@fte.co.uk 

Technorati Tags: Jeep,Wrangler,Cherokee,Axle,Off-Road,UJ's,Dana 30,Dana 44,TJ,XJ,ZJ,JK

Replacement Bushings for Rubicon Express Control Arms

Daystar is now offering heavy-duty polyurethane bushings available to replace the rubber hourglass bushings used in the company's long-arm and short-arm kits. Specially formulated from a unique new blend of polyurethane, these bushings have much of the same elasticity as the original rubber bushings, yet are capable of surviving the most demanding off-road conditions.

Designed as direct replacements for the larger and smaller "hourglass" bushings used in upper and lower Rubicon Express control arms, no modifications to the arms themselves will be needed and even the original sleeves can be re-used.  They are packaged in sets of eight; four large and four small bushings in each kit.

As soon as these are available we shall be stocking these at FTE 4x4 Specialists Ltd. We are hoping to be able to supply the bushes individually, rather then as set of 8.

Technorati Tags: Rubicon Express,DayStar,FTE 4x4 Specialists,Wrangler,TJ,XJ,ZJ,JK,Bushes

Tides Out (When was the last time you checked your diff oil?)

So when was the last time you checked your diff oil? A lot of people undo the filler plug and as soon as they see fluid (the reason I say fluid is it might be black but that does not mean it is oil) running out they screw the plug back in and the check is over it has oil! What is running out might well be a mixture of water and oil don’t forget oil floats on water, so when you filled the diff you only filled it to the bottom edge of the filler hole. So why is it running out? Could it be that the axle has water in it, so pushing the oil up higher in the diff housing!
 
The photo above left shows what can happen when the oil is not check correctly. The photo above on the right shows the line the oil/water mix was sitting at almost 30mm about the bottom edge of the filler hole.

 

 

 

 

This is the damage that has been done to this diff housing the corrosion is very bad. Once the diff and carrier is stripped out an assessment can be made on the condition of the components and hopefully it will only need new bearings, still a cost that could have been avoided with regular oil changes.

 

An easy way to change the oil in the Dana axles is to use a LubeLocker no more having to prise the diff cover off, or scrapping of the old RTV. Available from FTE 4x4 Specialists Ltd. 

 

Technorati Tags: Jeep,Wrangler,Cherokee,TJ,JK,XJ,ZJ,FTE 4x4 Specialits