SRW Testing

[whatcharterboat]

Hi , There has been a lot of talk about SRW conversions not being supported as far as warranty claims go. Just to throw in my 50 cents >I can tell you that there is an enormous amount of testing, documentation and interaction between the dealers, our transport authority and us as a company who does this type of work so that factory warranty and road worthiness can be maintained.

Just as an example> one of the main considerations is how brake performance can be effected by the larger diameter single rear wheels and to be compliant the vehicle has to remain within a very close tolerance of the original braking performance (running with the standard size wheels). As manufacturers are often unable to provide this data it means testing the original before fitting the larger SRW’s. Sounds simple enough but it ends up costing megabucks and is not something that can be done safely on the road so it usually requires the hire of a long bitumen airstrip in a quiet country town for three days (and a guy to follow us and tell us if there is any planes coming in. Serious. No skid marks on the piano keys either).

The testing consists of completely stopping the vehicle from various speeds, simulating front or rear failure, brake fade, handbrake hold on a given grade, etc, etc. Everything has to be recorded at different weights such as full GVM or with simulated weight of the final body (see the bags in the pics and our attempt at keeping the weight central under inertia). It means rigging the vehicle with a whole array of sensors such as pedal pressure, a fifth wheel, inertia, system air pressure, event timers, etc. and of course certified vehicle weights. Then there is the mechanical engineer with his data logging laptop. Oh yeah, you can just about throw away a couple of sets of tyres with big flat spots. BTW does anyone else want to STAND on the brakes at 100 kph with no load and no front brakes and try and keep the thing straight?

Obviously the truck passed everything with flying colours, but it is all about having the supporting documentation, especially as this vehicle was destined to be a passenger bus.
The vehicle is an FS550 Isuzu, (tilt cab retained) which was then stretched and fitted with our custom suspension but maybe that’s another thread. www.allterrainwarriors.com.au

[haven]

It's great that the Australian government agencies are willing to work with your company so you can improve the factory vehicle for use off-road.

Since litigation is the national pastime of the USA, upfitters here are taking big risk when they deviate from the tires, suspension and brakes provided by the manufacturers.

It would be great if Isuzu would import the FS550 4x4 to North America! I suppose the 25% tariff on trucks not assembled here, left over from the 1960s, is what keeps them out.

There's talk about a establishing a free-trade agreement with Thailand, where all the small pickups are manufactured. Maybe Isuzu will start building medium duty trucks in Thailand to take advantage. Importing boatloads of Toyota HiLux, Isuzu DMax and Mitsubishi Triton pickups won't help the United Auto Workers, however.

Chip Haven

[whatcharterboat]

Hi Chip, Sorry for the delayed response. Just got back. I help look after a lighthouse a 100 k's up the beach from here (Double Island Point). Took some pics on the way home of a Fuso Rosa 4wd at Red Canyon. Will put them up on the FG forum soon.

I agree with you about the boatloads of cheap utes from Thailand. But with fuel costs and your dollar at the moment, maybe its time your car industry had a major paradigm shift in the type of vehicles they produce. Why can't they produce small cabover trucks like the FG's and NPS's and tacoma/hilux style utes?

As for the Isuzu FS-550, I can tell you that they are probably the most commonly seen 4wd in the 10 ton bracket. Actually there isn't much else here of that size anyway. Wish someone did something halfway between an FG/NPS and the FS 550. An 8 tonner would be perfect for most of the vehicles we build.

We did a SRW conversion on a Isuzu FS-750 (13ton) trayback recently for a sand mining company. These two models are common choice for mining, power, telecomunication, etc. While they may not quite have the offroad ability of a MAN, they are comparatively good value, super reliable and importantly Isuzu have established a huge dealer/support network here.

Here is a couple of 550's that were working behind my house and 2 that we converted to buses. One does rainforest day tours and the other does outback extended tours.

[whatcharterboat]

FS 550 still with duals

[daniel ruops]

On July 22nd Stephen Stewart wrote:

"As for the question on double rear wheels".
"The reason for double rear wheels is weight distribution. If you want to use the same sized (interchangeable) wheels all round and you want to put the load at the back you end up needing to carry more weight on the rear axle. If you want the best off road performance you want equal weight distribution. Hence single rear wheels."

"It is this that leads (IMO) to much of the prejudice against double rear wheels rather than their inherent problems."

"They do have a couple of practical disadvantages but these are not that serious for most overland trips."

"1.) You can get rocks stuck between them."
"2.) Inflating and inspecting the inner wheel can be difficult."

"I have traveled for more than 100,000 km with one particular double rear wheel vehicle and during this time he has had rocks stuck between his wheels on say 10 occasions. He has never had to remove the wheels to get the rock out (just wrap a light tow rope round the rock and get another vehicle, usually me, to pull them out). You get into the routine of inspecting your wheels after driving over the (relatively rare) size of rocks that are a risk."

"Access to the valve stems of double rear wheels can be difficult, but a few dollars spent on the correct fittings, a decent pressure gauge and/or extensions is money well spent."

"If you really are intending to drive up mountains and climb sand dunes then you may need a genuine off-road vehicle (like a Unimog) but if you are "only" intending to do the sort of journeys I have been doing an under loaded reliable truck with decent departure angle is fine. If there is a 4x4 version then it may be worth considering."

[whatcharterboat]

Hi Daniel,

Can't find the thread you mentioned from the 22-07 to put things in context but I think I understand where you're coming from.

I really only put this post up as an example of the type of challenges we face to keep a vehicle legally roadworthy and not violate the manufactures specifications as far as warranty goes. The SRW/DRW debate is a little bit more involved than the 2 disadvantages mentioned and checking tyres and clearing rocks are not really a problem for someone adventurous enough to go offroad anyway.

When going to SRW on the FG's and Isuzu NPS's and FSS's, we of course go to a much higher rolling radius tyre which not only is smoother over the bumps(hence easier on the suspension) but alters the gearing considerably. IMO (and I stress My Opinion) these trucks are geared far too low with the original tyres. Having driven many before/after conversions the taller gearing is a quantum leap in the right direction. (ESPECIALLY if you have "an underloaded reliable truck"). I drove an FG with DRW for 4 years doing pipeline work before I started at Allterrainwarriors and the first time I drove a fully loaded FG tour bus with SRW up the beach I couldn't believe it was the same type of truck (DRW do not work in sand). Also drove a short trayback unloaded with SRW. It really went hard. Easily loose your licence in it anyway. And of course the fuel consumption is also improved proportionally.

As for going to a Mog or MAN, the price of them here isn't usually justified. The tour bus operators turn the vehicles over usually every 4 or 5 years and the expedition crew like the 6 ton size of the Jap trucks and also their dual personality. With fairly simple mods (springs, shocks, tyres, seats) they are extremely comfortable ON the highway (The Mogs i've been in certainly aren't) and they are far more capable OFF than most people give them credit for (and reliability and dealer network and and).

After saying all that, we still build a large number vehicles with DRW (and standard suspension) and they perform perfectly for their role. I included some pics of 2 similiar campers and 2 more similiar tour buses with SRW / DRW.

[whatcharterboat]

The one above in the bulldust has the duals. The silver one above is on Michelin 100R16 XZL's and this one is on 19.5/265 Hankooks.

[whatcharterboat]

Hi again David,

Thanks for the comments. The camera shy guy is Don. He’s checking the installation of the generator. It’s his first one actually in production. Very clever bloke. His website is www.watts2c.com.au . Look for the Powermaker. It’s got a little Yanmar diesel putting out 2.5KVA @ 24volts through some really smart controlling software. It’s worth a thread in itself.

Anyway regarding your question of wheel sizes for a dual purpose FG >>> surely its going to come down to what wheel/tyre combos you can get hold of in your location. One of the problems we have here is finding 16” wheels that are strong enough to handle a fully loaded FG, so we have just started using 19.5” x 8.25” rims with really thick plate centres. In Aus, there are a couple of good dual purpose tyres available to suit these. We normally get the offsets made so that the wheels are inline. For the Michelin XZL 100R16’s, we use custom 7.5” tubeless rims. However they will go on the standard 6.25”rims allright. The tyres are pretty close to 36” diameter. In an FG on the road with these you rarely use 1st gear to take off and 100k should be around 2800rpm from memory (I could check this if it was critical).

I just spoke to the mechanic who looks after a fleet of FG 4x4s that we built cause I wanted to get it right before I posted this. They recently took delivery of their 26th bus from us and they sell them at about 300,000k’s and usually operate with 7 buses. What he doesn’t know about fixing them isn’t worth knowing. The vehicles do about ¼ road, ¼ dirt road and ½ sand and they do about 80,000k’s on a set of Michelins. These FG’s are driven very hard too as they are always racing the tides on the beach. They don’t bother with the cost of custom offset wheels so they just use standard rims turned around on the back. There is a trick to this however and that is you have to use a spacer (in place of the inside DRW) and lock it down with the original DRW nuts. If you look at the rear hub you’ll see that it’s shape doesn’t provide a good seating surface and this allows flex in the original rim which will eventually cause it to crack. According to Sean the spacer supposedly takes care of this.

He tells me they have NEVER had a rear bearing failure through normal wear during the 300,000k’s and the only time he has ever replaced them is if they get damaged from the retaining nut coming loose. Twice as far as he can remember. Some of the outback FG mechanics now Araldite the nuts on as a failsafe. The outback vehicles cop a lot of badly corrugated roads at high speed like the one in the dusty pic above. BTW the fiberglass paneled bodies we build get swapped onto a new chassis twice and are usually sold on the third chassis. The others trucks get the back of the cab replaced and are sold as cab chassis or as a trayback.

We have gone to more serious offroad tyres using big Michelin XML’s which must be closer to 40” but they are very shortlived on the road and not cheap. I think we ran 9.5” rims with these. Very hard to get 16” XML’s here. Usually only brought in for military use on our 8wheel drive tanks (Sorry that’s the only way I can describe them. Maybe they’re called ASLAV’s).

Hope this helps, David. These pics from my phone so not so good.
Shouldn’t this be in the FG forum?

[charlieaarons]

One important consideration is that a US spec FG has 4.875 gears and an Australian spec has 5.71 gears, I believe. The difference in gearing makes fitting oversized tires to a US version questionable as far as gearing if the intention is to load up to near GVW.
On the other hand, gears can be changed; and maybe even lockers installed...
My experience with military Michelins is that XZLs are very durable on rocks but XMLs quickly disintegrate on rock; they should only be used in pure mud.
Charlie

[whatcharterboat]

Hi Charlie,

If that's the case, of course you are quite right. I never even considered that they would be a different spec and looking back I see that David mentioned it. Why would FUSO do this? Will have to check on this tomorrow and get back. It still might be a good thing given how well they perform with the even bigger XML's.

Thanks.

[FusoFG]

my 93 and 2004 have 5.71 gears. I don't think they changed the gears until the bigger (+ 100 lb ft torque) engine.

I think the standard tires and wheels give 32 kph / 1000 rpm

[whatcharterboat]

Hi David

They are not something that we make or fit so I'm guessing that the ones I've seen are 8 or 10mm and have the holes countersunk the same as the original wheels so that the inner DRW nuts can lock them down centrally. Obviously they are at least the diameter of the flat section of the original wheel centre. And no they are not to increase the width of the track as they are already to wide (hence why we get our own rims built).

I'm really concerned now about the different specs between US and Aus. I thought as "FusoFg" did and that all the previous models ran the 5.71 rear ratio and didn't realize there was a difference. You see the 4.9L model you have in the US won't arrive here till October (fingers crossed) and I haven't seen much info on it yet. If it has 4.87 diffs, and as this is such a big difference, I wonder if the transfer case ratios and the gearbox ratios are lower to compensate. Could someone tell me or direct me to a site that has the full gear split ratio specs.

Ours have 5th gear > 0.722, high range > 1.090 and as stated final ratio 5.714

I know the diff housings changed a bit here recently but I checked with some of the guys and the SRW Michelins have always given the around same 2800rpm @ 100k's so I think the gearing has always been similar.

Thanks

[charlieaarons]

I looked up the specs in both countries to get the axle designations. Unfortunately the US site doesn't give the axle designations but the Australian site does. The front axles have the same load spec; the rear has a greater load spec in the US. So I can't tell if the 5.71s are transplantable into the US models or not. The rear axle is called D033H; the front F020TW/D1H(SP) - in Australian models. Perhaps a US owners manual will tell?
I believe the transmission and transfer ratios are the same but I'm not 100% sure.
How much torque is the 4.9L motor supposed to produce?

Charlie

[dhackney]

U.S. current model Fuso FG gear ratios are here: http://www.hackneys.com/mitsu/index-specs.htm

Scroll down for the gear ratios.

[dhackney]

How much torque is the 4.9L motor supposed to produce?

Charlie

Here's the engine specs for the current model U.S.A. FE/FG series:

http://www.hackneys.com/mitsu/photos/fusoenginespecs.jpg

[edit to add the conversions]
347 lb ft = 47.974 kilogram force meter
391 lb ft = 54.058 kilogram force meter

147 HP = 108.118 kilowatts
175 HP = 128.712 kilowatts


The T8 is for the automatic transmission chassis. I did some preliminary research on the differences. My service manager and parts manager swore that the fuel pump, injectors, etc. were all identical part numbers between the two motors.

The Fuso factory service rep told my service manager they were different because the manual trans couldn't take the extra torque. My personal opinion was that it was more likely there were making up for the losses incurred by the torque converter of the auto trans.

At any rate, I did not procure the fuel injection computer or chip for the T8, so I don't know if it is a straight swap with the T7 or not.

[dhackney]

Unfortunately the US site doesn't give the axle designations but the Australian site does.
Charlie

Relevent pages to determine drivetrain components are here: http://www.hackneys.com/mitsu/docs/fusopowertrainpages.pdf

[daniel ruops]

whatcharterboat
Adventurer

Join Date: Jun 2008
Location: Noosa Heads, Australia
Posts: 31
Re: Hello Senor Whatcharterboat
Hi Dan

Thanks for the offer to come to the cesspool. It's actually in my plans to visit one day maybe in the next 5 years. I'm doing a Uni degree at the moment too so I'm a bit locked in. The customer who owns the IVECO in the pics has a shack down in Baja near good surf so I'm quite keen for a West Coast (or do you say Leftside) visit. Just be a matter of money.

(Please put this up as a separate post in the FG forum if you think its worth it and quote what I'm saying) Anyway regarging your question about DRW in sand > instead of running in the same wheel tracks, the DRW are breaking new ground and tend to drag rather than float. The biggest misconception people have about tyres on sand is that they have to be wide and float on top. It is not about having a wider footprint it's about having a LONGER one. (And IMO the narrower the better)

As I said in the post the Adventure Tours FG's don't bother with the correct offsets but that would be better. So when the FG's run into really soft stuff (usally coming off the beach) rather than charging at a dangerous pace, especially if your right next to a bogged Samari, they go forward till they start to go down, back up, go again but as they are still in there own wheel tracks they end up going a little further each time till they get through. Maybe 3 or 4 times. So they are sort of compacting hard tracks in their path. Can you see why a DRW is not the ideal setup for this?

BTW when I used to build offroad caravans it was always important to build the vans with the same track as the tow vehicle.

So regarding SRW, they tried big floatation tyres here and have now gone to the comparatively skinny Michelins which give a much longer footprint than the stock 7.50's. Even the road version of the XZL 100R16 was a good performer in sand but they are now longer available. There are some big MAN's over on Fraser running wider tyres but of course they are more than twice the weight.

Beach (soft sand) driving and the development of vehicles specifically for this is what the company that I work for was founded on and I myself have been heading up the beach surfing/camping since the seventies and still do. Noosa to Fraser Island (Cooloola National Park) is sort of like a mini Baja but only 15 minutes and a $5 ferry ride from my house.

Thanks for listening.

[whatcharterboat]

Hi Doug,

So looking at your gear ratios. They are the same as what we have here. Yes?
What has the 4.87 diffs then? The 07/08 models?

Regards.

[dhackney]

Hi Doug,

So looking at your gear ratios. They are the same as what we have here. Yes?
What has the 4.87 diffs then? The 07/08 models?

Regards.

John,

The data includes the 2007 models. I don't believe there were any changes for the 2008 models.

Chip is probably the best resource for what is current data for products on sale in North America.

I have not kept up with the new Fuso model changes since we started our build and subsequently left the U.S.

I think there is a new FG coming to the U.S.A. as a 2009 model, but Chip or someone back there would be better informed on that information than I am out here.

And BTW, thanks for your invaluable posts on what is possible on the Fuso chassis. I hope that your company has the oppotunity in the future to partner with an existing supplier or franchise operations into the U.S. market so people there can take advantage of your experience and capabilities.

Doug

[charlieaarons]

We have gone to more serious offroad tyres using big Michelin XML’s which must be closer to 40” but they are very shortlived on the road and not cheap. I think we ran 9.5” rims with these. Very hard to get 16” XML’s here. Usually only brought in for military use on our 8wheel drive tanks (Sorry that’s the only way I can describe them. Maybe they’re called ASLAV’s).


11.00R16 XZLs are the same height as 325s (38.7") and have almost the same footprint (90 sq" vs. 94 - a 7.50R16 is 44 sq") and load capacity (4360kg/axle vs 4600kg/axle). They fit on 6.5 or 7" rims. A North American FG with these tires and 5.71s (with one of the 4.9L motors) would do fine as far as gearing. 11.00s are marked as "limited availability" on my North American Michelin database.
As you know, XZLs wear very well on tarmac and rocks despite their fairly aggressive tread.
Also, I read that Locked Drive Systems has NoSpin (Detroit Locker) diffs for the D033H diff (FG) as well as larger Mitsubishi trucks.
Charlie

[whatcharterboat]

Hey Charlie thanks for the info on Locked Drive Systems. Sounds about right for the tyre sizes. Im sure my boss has the exact specs. I have trouble locating detailed info on them at the moment. I just know that the XZL 255/100R16 is about 930mm and the XML 325/85R16 is close to 1000mm and the 100's will just go on an FG with standard suspension (but 7.5" custom offset rims and long travel is better) but you have to relocate the Air-con condenser. The XML's need more major work( see pic) > custom offset widened rims, fiberglass flairs, long travel suspension, loose the bottom step, modify the mudflaps and the driver's side tyre may still rub on the steering arm at absolute full lock. Is it worth it? Offroad > sure it is. But onroad is another story. The gearing feels great but wear,noise and vibration. 100's put the speedo out by about 10% and the XML's out by 17% I seem to remember.

An example: On our test track, we have a very steep, rutted, loose (marble to golfball sized rocks) and long hillclimb. No run up area either. A friend went out there to have a play. He has a Taco (Hilux) with a 5" lift and 35" aggressive offroad tyres. He came back and told me about how just couldn't get up the "hill" and muttering something about a front air-locker. The FG putting close to 6ton on the ground through those big claws just went straightup with a change from 2nd to 1st in low range at the halfway mark. Obviously the Taco driver was a bit deflated.


. I hope that your company has the oppotunity in the future to partner with an existing supplier or franchise operations into the U.S. market so people there can take advantage of your experience and capabilities.

Doug. Thanks. Things are very quiet here and as I said before to you we are only a very small family run company and this may be our best option. My boss is aguably one of the most knowlagable guys with modifying offoad FG's and Jap trucks on the planet and our market here is so very small by comparison. Very down to earth (humble/honest) kind of guy too. Not the sort to blab on all day in a forum like me.

[whatcharterboat]

Just noticed the flex in the chassis in the middle pic. See the body line of the cab and body Also the bottom pic was quite steep I know it doesn't look it from the angle of the pic but you can see how the weight shifted cause he took it on an angle instead of going straight. I was in the truck following but the guys who took the pics said they took a deep breath all at once.

[dhackney]

Just noticed the flex in the chassis in the middle pic. See the body line of the cab and body Also the bottom pic was quite steep I know it doesn't look it from the angle of the pic but you can see how the weight shifted cause he took it on an angle instead of going straight. I was in the truck following but the guys who took the pics said they took a deep breath all at once.

This is the reason we built ours with a 3 point pivot frame. Once I saw the photos from Darrin Fink's torsional twist test of an FG I decided that any North American produced RV product rigidly mounted to that frame would self-destruct very soon.

Your company must obviously be building very strong bus/camper units to withstand the torsional forces we have experienced with our FG offroad.

More photos and info here: http://www.hackneys.com/mitsu/index-pivot-frame.htm

Re: North America
A small manufacturer with a proven track record such as Sportsmobile http://www.sportsmobile.com/ might be a good Joint Venture / Franchise fit for your company, especially their west coast division. A Fuso would be a good next class up vehicle chassis for them. They have knowledge of the NA market, sales channels, etc. - you have world class knowledge and a proven track record with the chassis, etc.

[whatcharterboat]

I'll pass this on to my boss. The financial market is pretty volatile at the moment. So I'm not sure. Certainly worth discussing with them. Absolutely.

The motorhome bodies have always been strong because we built them using the same steel frames as our buses which have to meet Government "rollover " standards. You would not believe what we have to go through to supply that documentation. However the one we are building at the moment will be of a full composite construction. Similar to a foam sandwich yacht and we will probably continue down that path, maybe with some rollover protection over the seating area only if it is expected to carry passengers in the rear while in transit.

About the body mounts, Sorry I must have misled you with that statement. The Fuso with the 4.5mm chassis, flex more than any other truck I've come across. Sorry I can't give full details but we have a really simple system allows the body to just sit on top of the chassis, without pivoting from side to side but still allows the chassis to fall away freely in any direction it needs to. So it is completely independant of the body.

This is something that Paul worked out many,many years ago (instead of copying a Mog) cause he was trying to better utilize the frame flex offroad but without the potential body roll and also keep the centre of gravity as low as possible. Our floors are still flat and maybe only an inch and a half or so above the transmisssion/step area.

Thanks Doug. Have just joined your mailing list. Very cool.

[1Engine]

Hi All,
I have just had the SRW conversion carried out by ATW on my 2002 Isuzu NPS300 115hp 4.6lt naturally aspirated service truck. The work carried out by John, Mark & the others in the workshop was great & nothing seemed to be too difficult. A great company to deal with.
The trip from home to Brisbane is just over 1600kms & we (myself, the wife & our 9yo son the navigator completed it in 2 days with stopping at Waverly Creek for some sleep. The return trip was carried out in the same time frame. The GVM for the trip down was 4500kg & return was 4900kg.
In some ways we were luck that we had similar conditions both ways. Air temp during the day between 30C & 38C, of a night 25C by the time we stopped. Between Ayr & Mackay both ways we had a head wind 15-20kph
Some comparisons before & after.
Before- Average speed 74kph, cruising at 80-85kph. Fuel usage overall 16.9l/100km
After- Average speed 82kph, cruising at 90-97kph. Fuel usage overall 16.8l/100km:smiley_drive:

[ozzyfishaman]

Hi 1Engine,do you have any suspension mods on the NPS?

Cheers John

[1Engine]

Hi John,
No suspension mods here. Just the wheels

Dave

[lehel1]

hello all

on our 08 fuso fg (us model) we are running 19.5 x 8.25 single rims with yokohama ty 303 tires 285/70-19.5, 35.4 high x 11.1 wide, weight rating 6615 per. we choose these commercial tires as we needed the ability to haul goods for our store.

we use our rig dual purpose, to haul for our general store as well as a camper. we've been very happy with these wheels and gearing change. we live in a mountanous area and haul at max gvw regularly, the power loss with the large tires is minimal. at 60 mph we are seeing just about a 4-5 mile difference on the speedo and gps. this has also helped our fuel mileage as the higher rpms really seems to reduce the mileage on our truck.

on our recent trip to death valley with our new camper installed, we traveled over a 100 miles of dirt, mud and 8-10" snow in the back country and we're happy to report the fuso is outstanding in offroad conditions. we aired down to 60 psi all around from our normal 85 front 95 rear (for hauling) and that worked well. not sure how far we'll be able to air down these tires in offroad conditions, we'll try alittle lower next trip and see how it goes. these tires are pretty stiff in the sidewall but preformed well.

cheers lehel and laura