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Challenge events with a 110” Defender, Possible???


Tom.H
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As a few of you may know I am planning to fit unimog 404 axels along with 40” tyres to a land rover defender, of some sort. I’ve been talking to a chap who has done the same setup (40” tyres, unimog axels) and put them on a defender 90. His truck is in the pictures below

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I was originally hoping to do exactly the same thing as him (fit the axels to a 90) and because of this I have recently brought a 90 pick up but after being told some more details I am starting to think that it may not have been such a wise idea.

Lately I’ve been told the dimensions of the blue one (in the pictures). It’s basically a cube being 90” high, 90” wide and 90” long which basically means it is as stable on side slope as it will be going up and down hills (not counting were most of the weight is)

Because if this I am now thinking about selling my recently brought 90 for 110 hi cap and fit unimog axels to it. By doing this the car will be far more stable (very strong) going up and down steep hills but the long wheel base creates new problems

If I was to go along with this plan I think the first thing I would need to do is bobtail it as even with the car standing on 40” tyres its rear overhang will still be very bad/poor departure angle. I’ve had a go at editing some pictures just to see what a bobtailed 110 looks like, this was the result

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I think it makes the car look a lot smaller and almost nimble compared to a standard one.

The other issue I think I am going to have with using a long wheel base car is that it turning circle will an issue. But from what I have heard unimog axels turn slightly tighter than standard land rover axels and if I was to fit fiddle brakes on the rear I may actually have a chance of turning without a shunt. I don’t yet know how effective fiddle brakes will be with 40” tyres but I am hoping to find out, somehow.

Anyway I am just trying to get this out my head; with fiddle brakes do you think I will be able to compete in challenge events such as the howlin wolf. Also if any one is able to help me out, tell me any problems I may have (bobtailing, fiddle brakes) it would be great. I have the mog axels all sorted out, doing them through portal rover. (going to bite the bullet and pay for all the work with the axels to be done by someone)

Thanks

Tom

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90" is very wide - it will struggle in many places on events. The risk you have is you could turn a perfectly good vehicle into a tractor - in open situations it may be very impressive but when it gets tight pretty much everything else will run rings round you.

Fiddle brakes are a good solution to the problem. They're going on the car I'm not building.

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Given how much Mog axles weigh I can't see stability of a 90 being a problem unless you tile the roof with lead or something.

However, to the business at hand - with 40's and portals you shouldn't really have too many issues with a 110, lrfun has a 110 on Volvo portals that you might find interesting: lrfun's 110. As for cube cars, Petal was 88" cubed and never had problems.

I only run 37's on my 109 and haven't found the breakover, departure or turning circles to be an issue, the first two are comparable to a 90 on reasonable tyres. RWD helps with the last one.

For every obstacle a short wheelbase will do better there's one where a longer wheelbase will do better. There's no right answer really.

Is Portal Rover just a different name for Straightforward Supplies? If it is, I'm not sure I'd be handing him my life savings... :ph34r:

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As per Firdge's remarks above, I shouldn't worry about latteral stablity in a 90 given the unsprung weight and the axle width (although the latter has validly been raised as a separate issue of concern). The problem, as you seem to have rightly identified, is fore and aft stability in a hill climb or rock-climbing situation. I am not very comfortable in my 88"(ish) on 36" tyres in steep climbs and a few extra inches of length isn't going to do it. On the other hand, 110 inches is awfully long when you get into woodland trail type terrain. I think you are onto something with the bobtail concept, but I would suggest taking it one step further. Chop it down to somewhere in the 100" - 104" wheelbase range and trayback it. That is an ideal wheelbase and the trayback has proven utility.

Why 40" tyres? Is it to aid in raising gearing ? If not, that's an awful lot of tyre. With the Mog axles you will have somewhere in the area of 22" under the diff. That seems....excessive. You will need a lot of power both to push those tyres around and to brake. If your heart is set on 40", so be it, but I find 18" under the diff on my C303 axles and 36" Swampers just fine, while I find their rolling resistance,even with a 3.5L V8, rather much.

In any event, good luck with your project.

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have you seen the Devon 4x4 trayback 110, have alook on there website for it. should give you some ideas

Yeah that is an aswame truck. Me and Jules had to look after it at Gayden so drove it a bit , Very very nice truck and nicly built

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Jules in the Truck

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Most challenge trucks about now and ones being built are around 100" to 106" so a 110 is not far of,

Turning circle is vital at this lengh, as is width, if you put a 40" tyre on a L/R they would stick out around 7 - 8" past body work,if you put another type axle try to keep it something like, this does help in tight wooded sections,

Everyone has an opinion about this so just go for what suits you but have a good look about at what trucks are doing well and take ideas from that,

Going big on the rubber then put some time into gearing, sort out trans box and ring/pinions to compensate,

Carl.

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Thanks for all your help

Tyres:

You can never have too much axel ground clearance :P:P No the main reason I have decided to go for such large tyres is to raise the gear ration, which is needed as mog axels have a very low ratio (overall of 7.56). So by going for 39.5 tyres (thinking ever pitbull rockers or super swamper tsl’s) I’ve worked out that I should be able to go about 40m.p.h with the standard transfer box, I think.

Width:

The truck will be just less than 90” wide as Steve (the owner of the blue 90) went for slightly too offset wheels but yes it is going to be quite a wide truck

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Axels:

Straightforward Supplies has been taken over by Portal Rover. He seems a very nice guy but sadly the prices have not decreased, it anything they may have actually gone up instead but then he supplies the axels bolt on and they are reconditioned.

NewPicture1-4.jpg

Tom

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matthew sykes has been using a 110 in challenges for many years. Muddy truckers, 3 peaks etc - not even bobtailed the rear overhang.

simple 3.5v8 on carbs and front and rear lockers + front and rear 8274. Super reliable and super simple. I dont think he complains too much about its length.....

rear tub has taken a bit of a beating, but them rubbing strips do the job.

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I should be able to go about 40m.p.h with the standard transfer box, I think.

So you're never going on the roads then? :ph34r: I'd be looking for a higher geared LT230 if I were you.

SFS, Portal Rover, whatever, is it still the same "quality" of fabrication as witnessed on the tack-welded yellow 90" abortion he bought to Billing two years ago? If you're paying serious money, I'd want serious quality in return, not stuff knocked up from lumps of box found laying round the floor of a barn.

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I am hoping to use the car on the road and drive it to and from events. And Yes I have thought about putting a different transfer box on but maybe later (lack of money).

I just want the car bobtailed on the axels and tyres. I think 40mph will just about be manageable to my nearest 4x4 sight . Anyway I’ve heard disco transfer boxes have a higher ratio than defender ones, so I think one of them will do the job (When I have the funds).

To be honest I don’t think I will wont to do much more than 60mph when the cars finished, when you think about how 40” and ½ ton (will be un sprung weight) there not going to be great, I don’t think it’s going to beat any records

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Sounds like you could do with a bit more research before throwing your chequebook at this TBH. You may not want to do more than 60mph but you'll probably want to be able to do it at less than 4000rpm. As for stopping, are you factoring in disc brakes, sticking with the stock drums, ? No real reason it shouldn't stop as well as any other car if you get it right.

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Yep, I Portal rover can supply the axels with a disk brake conversion. The conversion uses land rover calipers and disks so no modifications to the master cylinder have to be made. Like any drum brakes unimog ones aren’t great with sand, mud and water so I think it will be well worth the money.

As for transfer boxes: I have an option to either buy a used disco box, which won’t increase my speed all that much or get a custom made one, Again from portal rover. The boxes are specially made to go with mog axels and he says they will get you up to about 70-80mph but again this costs more than a second hand disco box.

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I believe some of the RRC transfer boxes were 1.003:1 high ratio which would add 20% over a 1.2:1 Discovery box, may be worth a look?

That's probably the "special" one PR are trying to sell you. I paid £50 for mine, and yes the car will do 70-80 happily although my gearing's a bit different to Mogs overall.

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To answer your original question yes you can compete, whether you'll be competitive is something I (or anyone else) will struggle to answer. Seems to me that reliability and the team matter as much as the vehicle's ability.

Oh and sorry to raise this one but you do realise bobtailing may cause issues with road legality/SVA ? read me

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Yep, I Portal rover can supply the axels with a disk brake conversion. The conversion uses land rover calipers and disks so no modifications to the master cylinder have to be made. Like any drum brakes unimog ones aren’t great with sand, mud and water so I think it will be well worth the money.

As for transfer boxes: I have an option to either buy a used disco box, which won’t increase my speed all that much or get a custom made one, Again from portal rover. The boxes are specially made to go with mog axels and he says they will get you up to about 70-80mph but again this costs more than a second hand disco box.

What are these 'special' boxes???? They don't seem to mention them on they're website and gear cutting is not a cheap thing so you'd expect them to shout about it. I'd put money on them being a 1:1 t.box which, as FF said can be had very cheaply.

Think very carefully about the SVA implications of doing something like this especially as you intend to use it quite a bit on road.

What do you plan to do about steering? Moglite found that a standard Land Rover setup didn't really cope with Mog Axles. That means you really need to factor in hydro assist (full hydro fails construction and use regs) which means more money.

What do you plan to do with winches? Given its a winch challenge vehicle this is where the first of the big money should go IMHO as it will make the most difference. A fairly standard car with a decent set of tyres (say 35" or so in your tread of choice) and a good spec winch (tweeked 8274, MM type R etc) driven by someone who knows what they're doing will go a long way.

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reading this with interest as the 90's here in Aus are far too short for the course and challenges in Aus

Need somthing a bit bigger and longer. Hence why the RRC is used alot here. 90's not used alot because they are far too short and small inside. Although not too many 90's here anyway

Compaired to alot of trucks raced / competing here the 110 is still alot short than alot of the nissans and toyotas, they are knocking on the door of a Defender 130 style wheel base

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That's probably the "special" one PR are trying to sell you. I paid £50 for mine, and yes the car will do 70-80 happily although my gearing's a bit different to Mogs overall.

LOL! Perhaps a little too subtle in this case. You did try to save him though...

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Thanks for all your replies

Because of the comment ‘sheeppimp’ made about going through an SVA I’ve decided that it wouldnt be worth bobtailing a 110. The car will have been lifted through the tyres and portal axels so high I don’t think it will be too much of an issue anyway.

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Anyway after talking to a few people about this project a few of them have said, why not just use a unimog. A 404 has a 114” wheel base so 4” longer than the 110 land rover. I also suspect it would cost a lot less than the 110 project but I still think its a rather big jump. :o Just a thought :o

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Tom

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It's a good point, if I had any sense I'd have scrapped my 109 and just bought a 6x6 Volvo :rolleyes:

A Mog with a decent engine and a coat of looking at would probably be very capable, although they definitely *do* suffer stability issues down steep slopes (some ballast on the back end could be a good idea). Plenty of room for tyres, no SVA issues, classic insurance, and it's a bit different to another bl**dy defender :ph34r:

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The truck will be just less than 90” wide as Steve (the owner of the blue 90) went for slightly too offset wheels but yes it is going to be quite a wide truck

P5310040.jpg

You prehaps want to have an in depth conversation with the owner of that 90 as he very rarely ventures out into very nasty stuff, i've only ever seen him in deep mud and bogs, the car seems allergic to hill climbs and rock sections

Straightforward Supplies has been taken over by Portal Rover. He seems a very nice guy but sadly the prices have not decreased, it anything they may have actually gone up instead but then he supplies the axels bolt on and they are reconditioned.

NewPicture1-4.jpg

Tom

Steer well clear of that dog s**t brake conversion. mounting the callipers off the sandwich bolts is asking for trouble, and the way they reverse the hubs makes you way to wide.

From personal experiance anything wider than 80" overall will hurt you big time in challenge event.

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