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Axle components - What to upgrade first?


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This has been asked many times before but things move on and new products come onto the market (as well as businesses going bust, which seeems more common these days).

Let's say you have a set of P-reg/1996 Disco axles, all standard internals. These hypothetical axles have a fair bit of play and could use a general refresh including swivels, pins etc. So it's likely they'll need some pretty significant bits (shafts, diff, etc).

The vehicle is used for everything from being a load lugger to taking part in the more challenging end of drive-round/pay and play days. Let's assume it has 255/85 BFG muds on for this purpose. The vehicle has to work when required and the object is to make it as capable as possible while keeping things as standard/simple as possible and making it no worse on road - no outlandish suspension changes, only upgrades to the axle for reliability/strength.

My thoughts are a pair of Ashlockers and associated gubbins, but these are quite a cost so keen to hear other options and opinions.

What would you start with first?

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If you are happy with diff ratios, keep the factory CW&P if in good condition. These are not junk like some people seem to think.

96 D1, Def’r etc have the worst CVs. I would up grade these to the AEU2522 size. Unfortunately LR never made a 23/24 spline axle shaft so you’ll need aftermarket. New flanges with screw on caps are worth it and you can run oil throughout. 
 

The factory hemisphere is junk. A open or selective locker diff should be 4 pinion gears. You can get HD non locking hemispheres or your choice of selective lockers that are all 4 pinion. I’m personally not a fan of auto style lockers in axles. 
 

You're probably in the UK so Ashcroft makes sense and makes good products 

Diff pegging is ok but would be last on my list for your needs. 
 

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The post 93/94 front shafts are the worst weakness.  Look for Nige’s half shaft video for a good explanation.  Fitting the 24-23 spline shafts from Ashcroft would be a huge leap in strength.  The trouble is they would also need the bigger diameter CVS, which then require modified stub axles.  All available from Ashcroft, but the price stacks up.

The next weakness is the diff itself.  The single cross pin is weak, but the carrier is weaker and I had a low mileage 90 keep throwing the cross pin because it’d shear the retaining split pin through the end of the cross pin and carrier.  In hindsight, I think the carrier’s hole was ovalised, allowing the cross pin to move laterally in the hole under load and shear the roll pin.  The cross pin didn’t break and we never lost drive, but the end of the pin would hit the top face of the pinion gear.  It made a bit of noise and caused cosmetic damage, but eventually it’d have broken something badly. A locking diff or ATB would avoid these problems.

If you play hard off road, especially with oversized tyres, the next thing to think about would be pegging the diff.

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@Snagger it’s s just swapping the needle roller out for a bronze bush. MaxiDrive use to make and keep them in stock, I’d imagine Ashcroft would do/have something similar. The earlier CV is longer so if pairing with the later stub axles and hubs you just need a deeper/thicker drive flange to make up the difference, again something MaxiDrive kept in stock. I think Ashcroft might even offer a custom short stub shaft CV to fit this application. 
 

Edit: ok so I just looked at the Ashcroft website, they offer 2 types of CV. AEU2522 replacement and a custom later replacement which has the bigger star etc but has the stub shaft , shoulder etc to fit later narrow stubs with needle roller. 
 

Below is a photo of how MaxiDrive did it. They retained the later factory bronze bush which controlled outward float, and replaced the needle roller with an internal bronze bush. I think no stub axle machining was involved (IIRC) 

 

4C59AAA6-B59C-44E2-8FE6-311A4536D1DC.thumb.jpeg.0ebb2ad964b062723c0ba37e142ad895.jpeg

Edited by uninformed
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On 1/13/2023 at 7:26 PM, ThreePointFive said:

make it as capable as possible

That to me screams adding a locker. People say LSD etc., but I like the preemptive nature of being able to engage it before needing to. All other kinds are reactive, i.e. something has to happen before they respond.

People make a big song and dance about upgrading everything else like half shafts and CVs at the same time but in reality are they needed? I did because they needed doing and I could comfortably afford to at the time but rather ironically it meant my weakest link then became the crankshaft because the only thing I've damaged since the upgrades was snapping two cranks :lol:. Sympathetic driving will do more for saving components than anything else, after all the standard ones have got a lot of people around a lot of the world in a whole host of setups. What lockers do allow is more control over being sympathetic to the drive train as you can lock them all and not have to spin wheels and shock load components in order to find traction. If you're spinning wheels with all four wheels locked either you don't have traction or your driving can improve.

Of course adding lockers might necessitate extra expense such as compressors and changing other components but that's down to the individual vehicle's wear, tear and setup. My initial air setup cost under £100 because I sourced a second hand air con pump and bracket, most of the expense came from pipework.

Cheaper upgrades are certainly possible but none will be as profound I feel.

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You have to consider application when deciding what capability means.  Full lockers for a vehicle used just on roads and tracks is less capable than an ATB as it has to be left unlocked the bulk of the time and would be dangerous on wintry roads.  But for a vehicle that is used on play sites, quarries, beaches and so on, a full locker would be far better.

I can’t see much debate about the front half shafts and CV joints.  The types from the mid 90s onwards are weak, so will break if you push much torque through them.  Yes, better to break them than a crank shaft, but that seems an extraordinary circumstance (and to do it twice makes me suspicious of the trueness of your block and bearings).  It’s a shame that KAM Diffs’ fusible stub shafts between CV and hub are no longer in production and also incompatible with the uprated Ashcroft CVs.  But if you drive with any degree of mechanical sympathy, the threat to gear box and engine should be small.  I have to say I’m a little torn - I’ll be fitting ATBs in both my RRC axles, and the front stub axles need replacing anyway, but as the car is not going to be used on significant off road surfaces, just wet and snowy roads and occasional tracks or grass, it shouldn’t need the uprated parts.  At £170 for the modified stubs, £570 for the special CVS and £250 for the shafts, all plus VAT, it’s quite an outlay if not needed.  On the other hand, if it saves the car from a blown shaft and contaminated diff or CV in the middle of nowhere in bad weather, that £1k+ could save itself and a lot more without you ever knowing it…

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7 minutes ago, Snagger said:

You have to consider application when deciding what capability means.

Did you read the first post? :P

On 1/13/2023 at 7:26 PM, ThreePointFive said:

everything from being a load lugger to taking part in the more challenging end of drive-round/pay and play days.

I'd say as load lugger then standard open diffs would be fine as after all pretty much all Land Rovers are capable of 7t+ GTW in standard form. Then the latter answers whether it's on-road or off road.

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While I'm a big fan of manually selected lockers, I think ATBs are the best compromise between price and performance, along with ease of fitting. And as said, they offer some advantages on slippery roads as well, where a full locker can only be used with proper care or it will make things worse.

The upside of fitting a locker (any kind) is that it's also stronger than a standard open diff, especially a 2-pin. If budget allows, it's probably a good idea to upgrade shafts and CVs at the same time. But be gentle, and you'll probably be fine with the standard components as well. If it's not your only vehicle and/or you don't need it every day, you could wait for something to expose itself as the weakest link before replacing it. Not if you plan to go overlanding of course!

When I fitted my ARBs in my Defender back in the day, I also fitted Ashcroft all round. Those lasted, but I did break a front prop and twice the ring and pinion. Mind you, that was after fitting 37" Baja Claws, on 255 muds everything was fine. I'm gonna risk Ashcroft lockers with 33" Baja's and standard shafts on the P38, simply because there are no upgrades available. I did have the diffs pegged this time.

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33 minutes ago, Ed Poore said:

Did you read the first post? :P

I'd say as load lugger then standard open diffs would be fine as after all pretty much all Land Rovers are capable of 7t+ GTW in standard form. Then the latter answers whether it's on-road or off road.

Yes, I did.  In this case, depending on how much pay and play vs how much severe winter driving he does, he will lean one way or the other.  Load lugging, an open diff is fine, so that wouldn’t be compromised by a full locker.  That said, for pay and play sites and light competition like RTV trials, an ATB is usually ample.  So, in those cases, either diff is suitable.  But if the vehicle gets used a lot in snow, or is used in more extreme off roading, then that  will dictate one or another.  The original post gave useful information, but I think it was too vague and generalised to give a specific answer.

As pointed out by others, cost and complexity of installation is also a consideration.

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13 hours ago, Snagger said:

 The original post gave useful information, but I think it was too vague and generalised to give a specific answer.

Indeed, I didn't want to lead the witness! :D

The other use case for the car is poor weather (a reason I went with these tyres), I admit I had no idea that full lockers were a bad idea, and I am not new to driving in terrible conditions! I assume that's because you'll get sudden grip on one side and get flung off towards the side with least grip without warning? I was almost set on manual lockers as I wanted the control/choice and didn't want any funny business with turning circles on a locker deciding for me. I need to do more research into ATBs it seems. Not all of my offroading is recreational so it needs to work when called upon, hence the capability requirement.

On 1/13/2023 at 8:23 PM, Gazzar said:

Flanges, CVs, shafts, front ATB, rear ATB, pegged diff casings.

So in short, everything then!

There's so much in the above posts that I need to understand and consider, I am very grateful that anyone bothers to put their thoughts and experience down as it's really valuable. I didn't know I had time-bomb components, I went to Disco axles because they're 24 spline and rear discs, so finding this out was a surprise but necessary.

I wanted to avoid mods to the axle itself (upgrading/beefing up internals aside) so I get a bit twitchy when it comes to this stub axle bit. Explaining the mods in the way an insurance broker call centre agent gets tricky. As long as it is straightforward to do and can be reversed... I accept it's a key to getting around that specific weakness though.

I am surprised I didn't break something last time out, one of the downsides of ATs is using revs to deal with obstacles. My normal off roading 'style' is to always try to walk the car over anything, I don't like ragging it with the wheels spinning - that's one of the reasons I'll be changing the larger mud tyres, the other reason being increased ground clearance. It's not a challenge truck and I don't enjoy driving it like that. Last time I did, bits of diff made a surprise appearance out the bottom of the casing. On that day, I learnt the joys of mechanical sympathy.

This sounds like a project to do over time, so unless there are pressing reasons to do it a different way, I'll do the diffs (manual or ATB) and shafts, then work my way to the outer components.

Oh, and I've never heard of anyone snapping a crank! I would have thought there's some much more likely components in the gearbox long before you get into that...!

 

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Ashlockers, Ashcroft shafts and CV's, job done.

if you are having the diffs built and can easily afford the peg them then why not but I doubt you will see the benefit unless you radically change the outlined use.

With the same front axle setup I broke 8 or 9 drivers CVs on a standard front diff (3 in one day) at that point I fitted an open 4 pin ( pre ash lockers days so the price was considerably less) and Ashcroft shafts and cvs with HD drive flanges, touch wood nothing more ever broke and it wasn't for a lack of trying. 

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9 hours ago, ThreePointFive said:

I admit I had no idea that full lockers were a bad idea, and I am not new to driving in terrible conditions! I assume that's because you'll get sudden grip on one side and get flung off towards the side with least grip without warning?

Not something I've experienced in the slightest. I'm assuming when you mean bad conditions on the road then it's down to ice and snow?

I wouldn't ever think of engaging them at "high speeds" say above 20mph so suddenly coming across different traction conditions is largely moot. In the recent icy conditions we had down here (whilst the rest of the country had some snow before Christmas we just got the roads turning to sheet ice where they hadn't been gritted) I still had to go out and about with a trailer (fetching bales of hay for animals etc). If conditions were that bad I'd quite often drop down to low range and lock the centre diff to counteract slightly what you describe. I'm not overly concerned about running that diff locked on the road because you can feel the steering get very heavy to the point of not wanting to turn but at that point you can disengage it because you know you have decent traction.

If I came across, for example, on of the bigger hills with ice on then on the straight bits I'd engage the rear locker before setting off. You can feel things beginning to get heavy and struggle to steer quite readily I find so it's easy enough to quickly unlock the diff, make the turn and re-engage if it's a sharp one. If you're on slipper surfaces then it's irrelevant because the wheel just slips.

Contrary to your comment I find it far more predictable driving in those conditions because you know the wheels are all locked together. When you're going downhill then potentially you might induce a skid because of a wheel having to skid to go around a corner but then the flip side (and a bigger benefit in my experience) is keeping all the wheels locked together so you have greater traction overall so the risk of a slide is less overall.

It's really just getting used to the way the vehicle responds in any situation. I've personally not had any experience of LSDs in a Defender, the Range Rover has them but then it also has a very capable traction control system so you're isolated somewhat (still doesn't get you out of trouble as I found recently). Of the two systems I prefer the Defender setup mainly, I suspect, because I learnt to drive off road and have the experience and like being in control. Another factor may be tyres, I'm running mud terrains all the time so I know that they tend to break traction before breaking something driveline related. Whether that'd be the case with standard components (running Ashcroft HD all around) I don't know.

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As above, in poor conditions on road just leave the locker open, unless you really need it. Like on a steep slope or setting of when snowed in. With an open diff, if one wheel slips, the other will sit still and provide lateral grip. I've never found the need to lock the diffs unless (seriously) off road.

I'd stay away from an LSD (as in, speed dependent lock-up, as used by some Jap pick-ups etc, as that could surprise you when locking up) but a TorSen (like the ATB) will help you find more traction without sudden changes. It should allow you to drive faster, not necessarily safer though. Remember a TorSen is also used in fast cars to promote over steer and make drifting easier. Driven with some sympathy it shouldn't be a real problem, especially with permanent 4x4 but you do risk spinning 2 wheels instead of one if you're to hard on the throttle or misjudge a situation.

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The problem with locked diffs on a slippery road is that on anything more than a very slight bend, they will force a tyre to lose grip.  Once that happens, only one tyre is going to be aiding control, and that tyre’s grip could be compromised by the windup from the opposite side too.  In a straight line, it’s arguably more predictable and balanced, so for a straight hill climb, then it may be slightly better than an ATB.  The ATB in those conditions is not locked and doesn’t even have the cross-resistance of a classic LSD that could force a skid on a poor surface; the ATB will send torque to where it has traction but will never lock up and force both wheels to turn at the same speed.  That is why they are so good for road use.

It’s not even about road speed.  Imagine all those snow covered city road videos shown on social media, where there is very little grip.  Road speed is a crawl, but turns are relatively tight and a locked diff or classic LSD would almost certainly cause a loss of control in those conditions, where an open diff would just cause a loss of drive but an ATB would give far more drive than an open diff and may be enough to get you through without compromising control.  That’s the theory, anyway.  If you have ETC, even better.

Of course, all the ETC and diff trickery in the world will give you nothing if the tyres aren’t appropriate - that is always the most important factor: double of zero grip is still zero.

But, for pay and play, a locker is more capable.

I will try to find Nige’s half shaft video.  It is quite illuminating.  But don’t be too paranoid - you haven’t broken a shaft or CV yet, so it can’t be that desperate.  For heavy competition, they’re essential, but light use, the jury is out…

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Here:

 

Just as an addendum, there was also a relatively uncommon 10-32 spline shaft, during the transition from the 10-23 to the 24-32.  They were the weakest of the lot, though they should theoretically be no worse than the 24-32 as they share the same thinnest point.  
 

The 24-23 spline shafts as “option 3” on the video are aftermarket only, not genuine parts.  They suit both older axles being upgraded with later diffs (like my 109 with early Discovery front axle) and the later vehicles being upgraded with early or aftermarket CV joints, which is the scenario you and I are in with our 300Tdi vehicles.

 

 

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I wouldn’t describe the later 24-spline components as a ‘time bomb’. Under normal use they will be absolutely fine. I swapped the internals of my 90’s front axle from the earlier stronger CVs to the later ones for a few reasons and yes in theory I have lost some strength but I use the car for green laning and trips abroad, where your right foot is the biggest factor in whether you will break something.

Upgraded parts will undeniably be better, just whether they’re worth it from a financial point of view will be down to your use case(s).

Breaking traction on snow/ice at low speed is a real risk, no idea about it being caused by axle lockers etc. as I’ve never had (or needed) any but I did once change down a gear at low speed on an icy road and the wheels broke traction and the car spun 180° as a result :lol:

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9 hours ago, muddy said:

Ashlockers, Ashcroft shafts and CV's, job done.

if you are having the diffs built and can easily afford the peg them then why not but I doubt you will see the benefit unless you radically change the outlined use.

With the same front axle setup I broke 8 or 9 drivers CVs on a standard front diff (3 in one day) at that point I fitted an open 4 pin ( pre ash lockers days so the price was considerably less) and Ashcroft shafts and cvs with HD drive flanges, touch wood nothing more ever broke and it wasn't for a lack of trying. 

I am minded to heed your advice. I vividly remember  when I put this photo up in 2009, you commented "BANG, and the diff is gone"...

90DRDCulmhead1.jpg.5dcea1c34b62965c2359a57185c96d26.jpg

..and this happened the next time out (on a much less severe, gentle piece of ground being driven more normally).

Diff4.jpg.e86f2707e7d4709ae73e8df1d1ddceef.jpg

That was a factory 2-pin front diff. The rear was fine, I'm told it would have been a 4 pin in the V8 CSW. It was my first and last trip into the 'drive it like you stole it' camp of off roading.

As a first shopping list, yours works for me. It will have other benefits in reducing what I think is a ton of play in the transmission (see other threads recently...) with new parts. While I wanted to select something based on what was right for me, rather than what was cheap, I didn't realise that ATBs were so much less than manual lockers. I can get a full set of Ashcroft ATBs and shafts for the same as just a pair of Ashlockers. Unsure if pegging (now I sound like Mo) is necessary or not, but there's almost no point not to if they're out of the car anyway.

I was always set on manual lockers as I wanted the choice/control - and, frankly, to see how much further I got for my money - but I'm starting to think ATBs might be the better way to go. I just hope they do deliver off road or it's saving money for no benefit.

 

4 hours ago, Retroanaconda said:

I wouldn’t describe the later 24-spline components as a ‘time bomb’. Under normal use they will be absolutely fine. I swapped the internals of my 90’s front axle from the earlier stronger CVs to the later ones for a few reasons and yes in theory I have lost some strength but I use the car for green laning and trips abroad, where your right foot is the biggest factor in whether you will break something.

Upgraded parts will undeniably be better, just whether they’re worth it from a financial point of view will be down to your use case(s).

Breaking traction on snow/ice at low speed is a real risk, no idea about it being caused by axle lockers etc. as I’ve never had (or needed) any but I did once change down a gear at low speed on an icy road and the wheels broke traction and the car spun 180° as a result :lol:

You describe what I think my driving style is with the last paragraph, and I agree that's the realy control over breakages. This is all really insurance about getting somewhere I shouldn't and having the ability to get back out of it without then causing mechanical damage. I know the addage is that lockers get you further into the woods to get stuck, but common sense still plays a factor.

As to whether it's financially worth it or not, that boat sailed a while ago on my car.

 

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I was recovering a Rocky (Fourtrack in UK) yesterday, with Tommy the Lightweight. The Rocky has no lockers but a determined driver that dug quite a hole. Even if he had gotten stuck with lockers, it would have been a lot easier to get him out. Of course, chances are then he then would have found an even deeper hole to get stuck in...

But in general, lockers are a great upgrade and will keep you out of trouble in most cases. They also allow you to tackle obstacles without needing to resort to momentum. An ATB will be very noticeable if traction is low. I'd even say you get more for your money, just not the full monty. And no buttons to play with, whether that's a pro or a con is for each to decide. I like the added control but certainly wouldn't dismiss an ATB either.

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The increased use of momentum with open diffs is a fair point, perhaps getting you into the same depths of flag that fancy diffs do.  It is an oft-repeated view that traction aids get you stuck further into the obstacle, but perhaps that use of momentum achieves as much, or worse, in getting stuck on rocks, stumps and bottoming out. 🤔

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There is no denying that the better equipped your car is, the further you can make it before getting stuck. And the more difficult it will be for others to reach and recover you. After all, there is nothing stopping you from using momentum with lockers, unless some sense of mechanical sympathy and/or common sense. And most of us drive our LRs for the fun of it, so will deliberately seek the limits, not just try to get from A to B. Except maybe some overlanders. I just think the more traction you have, the easier it is to hold back a bit and not get into so much trouble trying to follow the herd or prove yourself. 😉 

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2 hours ago, Escape said:

There is no denying that the better equipped your car is, the further you can make it before getting stuck. And the more difficult it will be for others to reach and recover you. After all, there is nothing stopping you from using momentum with lockers, unless some sense of mechanical sympathy and/or common sense. And most of us drive our LRs for the fun of it, so will deliberately seek the limits, not just try to get from A to B. Except maybe some overlanders. I just think the more traction you have, the easier it is to hold back a bit and not get into so much trouble trying to follow the herd or prove yourself. 😉 

I agree with most of this ^^^^^^

For me as I gained in confidence when learning to off road, my vehicle became less able

This is when the modifications started on what was a bog standard lightweight, bigger tyres first..and then here we are, coils, lockers, front and rear winches and now portals

My lightweight is my toy, not my daily driver, therefore it gets pushed to and beyond its limits sometimes resulting in damage ( quite often when doing modified trials with fiddle brakes ) just to see how far through or over I can get

@Escape is correct some of us seek the limits of our personal abilities, be that driving fast, offroading, exercising, electronics, modifying our vehicles etc, it's what makes us tic

Regards Stephen

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5 hours ago, Snagger said:

The increased use of momentum with open diffs is a fair point, perhaps getting you into the same depths of flag that fancy diffs do.  It is an oft-repeated view that traction aids get you stuck further into the obstacle, but perhaps that use of momentum achieves as much, or worse, in getting stuck on rocks, stumps and bottoming out. 🤔

Another point might be that with the increased use of momentum you are possibly more likely to do damage to components. Of course it's down to the driver that once they have traction aids such as lockers that they don't also use extra momentum to get stuck even further. Basically they allow you to overcome the same obstacles in a much more controlled manner.

I actually use the lockers quite a lot on lanes, partly because I spent quite a bit of money installing them, but I also find that it provides a much more pleasant ride. Some people I've been out with like seeing how far they can get without resorting to engaging lockers (i.e. using a more standard vehicle), I take (perhaps slightly a perverse) pleasure in seeing how slowly I can creep through an obstacle.

In the summer we joined a friend to help him out guiding a trip in the Highlands, the last track has a potentially* quite dangerous hill climb on it if things go wrong - you can easily bypass it and some do but the vast majority use it as an opportunity to learn. I suspect for the vast majority of people on this forum it would be a non-event but given the majority of these people haven't been "off-road" with their vehicles it's an eye opener. It's only about 100ft but a 60%+ slope (>31°) on a loose surface. The only two crucial bits are ensuring sufficient momentum to get up and making sure you turn left at the top because otherwise you suddenly drop onto a nice 45° side-slope you can't see until your front wheels are on it. On this summer's trip I sat in the vehicle for almost everyone to offer advice if they needed and we practiced good failed hill-climb descents on the start of the slope before they tackled the full climb. Anyway those who wanted a go had a go, then they all wanted me to drive up. There's a video somewhere of one of the group shouting "he's not going fast enough!" as I set off in low second just above a tick-over (but with all three lockers engaged and the anti-roll bar disengaged). The friend in charge of the trip just replied "he knows what he's doing". Well it was a rather uneventful pottering climb up with very minimal wheel slipping, oh so satisfying! :D One of the clients at the end of the track commented about how uneventful and simple my 110 made things look compared to everyone else (mixture of modern pick-ups, Land Cruisers, Defenders etc). That was a very welcome comment.

* they have had rolls on it down, largely, to inexperience when someone fails the hill-climb and loses control on the way back down.

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