lurch Posted January 25, 2009 Share Posted January 25, 2009 Hi I have a 97 300 tdi and am going to mod it for some serious offroading and would like some advice before I even start! I always see on here people asking how to go from 33,s then to 35,s then to 37,s so I have decided to do it the easy way or not and go straight to 37,s. What i have decided to go for is the Scorpion Racing Extreme kit with I hope a 3" lift from that I will also be fitting double cardan propshafts, upgrading the half shafts, cv joints, rose jointed panhard rods and trailing arms etc I am also going to fit ARB Air Lockers front and back. What I need to know is how much of a body lift am I going to need and how much of the arches will I needs to lose to get some 37,s on it. it is a 3 dooor so no major problem cutting a fair bit of body out. Also if anyone can help what sort of ratio would you sugest for this set up. I would like to get it right the first time so any advice is welcome Cheers Quote Link to comment Share on other sites More sharing options...
lurch Posted January 25, 2009 Author Share Posted January 25, 2009 Hi I have a 97 300 tdi and am going to mod it for some serious offroading and would like some advice before I even start! I always see on here people asking how to go from 33,s then to 35,s then to 37,s so I have decided to do it the easy way or not and go straight to 37,s. What i have decided to go for is the Scorpion Racing Extreme kit with I hope a 3" lift from that I will also be fitting double cardan propshafts, upgrading the half shafts, cv joints, rose jointed panhard rods and trailing arms etc I am also going to fit ARB Air Lockers front and back. What I need to know is how much of a body lift am I going to need and how much of the arches will I needs to lose to get some 37,s on it. it is a 3 dooor so no major problem cutting a fair bit of body out. Also if anyone can help what sort of ratio would you sugest for this set up. I would like to get it right the first time so any advice is welcome Cheers Quote Link to comment Share on other sites More sharing options...
BogMonster Posted January 26, 2009 Share Posted January 26, 2009 Can't help you on the lift but in terms of ratios 37" are about a 28% increase on standard tyres which are just under 29" diameter so you need to lose about the same in your ratios. Whether you do this by changing the 1.22 transfer box to a 1.67:1 (which will leave it a little lower geared in high range but still the much higher low range) or a proper job and change the diff ratios is up to you. 37s on a Discovery are going to be an interesting challenge Quote Link to comment Share on other sites More sharing options...
Anderzander Posted January 26, 2009 Share Posted January 26, 2009 Can we talk you out of using the Scorpion gear? And tempt you with the superior Gwyn Lewis kit? Quote Link to comment Share on other sites More sharing options...
plasticbadger Posted January 26, 2009 Share Posted January 26, 2009 To answer your questions: Lift: I'm running 4" to 5" lift with +2" bump stops. The lift shouldn't really effect clearance when you're off road as the suspension will be compressed regularily. 3" lift should just about be OK. Get good quality shocks though because with that much lift it's gonna wallow like a pig. Running gear: For 37's you'll definately need uprated diffs, shafts, CVs etc. For the amount of lift though get 30 degree props from Glwyn Lewis, much cheaper than the double carden ones, which you don't really need. I'd also recommend Glwyn for the suspension. Body lift: Don't go too big as you'll start to run into all sorts of problems with steering, gear shift, plumbing etc. 40mm to 50mm is about right. Try looking for Wizard Bilt on ebay. Wheels arches: I had cut down defender arches on my Disco with 37's and they still caught the tyres. I'm currently fitting 3" Innovation 4x4 arches to my Rangie on 37's and I don't think they're gonna be big enough. The tyres will also rub at the back of the rear inner arches, both front and back of the front inner arches, on the radius arms, rock sliders (if you have them) and probably more. The answer is cut at lot off everything - don't be shy! Ratio: 4.7:1 diffs would return you to near standard, but you might get away with 4.1:1 (which is what I'm running and it's a bit over geared, but only about the same as 32" tyres on standard ratio). You might want to look at an axle swap, because even with the uprated parts 37" tyres are big to put on Landrover axles for heavy off road work. The money involved is scarry too. Don't forget the effect of the tyres on the brakes as well. I'm running Toyota Landcruiser axles under my Disco/Rangie which also gives me bigger brakes, bearings, diff ring gears and more. Quote Link to comment Share on other sites More sharing options...
Orgasmic Farmer Posted January 26, 2009 Share Posted January 26, 2009 36" tyres on a Disco with a 2 " lift.......... Quote Link to comment Share on other sites More sharing options...
q-rover Posted January 26, 2009 Share Posted January 26, 2009 Only minor trimming needed then. B) Quote Link to comment Share on other sites More sharing options...
kellyv8 Posted January 26, 2009 Share Posted January 26, 2009 i done this conversion on my two door i used a two inch lift wide angle props salisbury rear axleand the 1.6 ratio box you need alot of reworking of the arches i cut my rears out and stuck in some series rear tub ones upside down the fronts i extended too and had to rework the throttle pedal looked good though and didnt drive too bad if you do a search you should find some pics Quote Link to comment Share on other sites More sharing options...
BogMonster Posted January 26, 2009 Share Posted January 26, 2009 2 virtually identical threads have now been merged! Quote Link to comment Share on other sites More sharing options...
plasticbadger Posted January 26, 2009 Share Posted January 26, 2009 My Disco on 37's Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 26, 2009 Share Posted January 26, 2009 I agree with Mr Badger, a toyota or similar axle swap is going to be much cheaper in the long run considering the donor vehicles can be had complete for around the price of an ARB locker. Rovers are at their limit with 37's no matter how big your chequebook is. Quote Link to comment Share on other sites More sharing options...
clbarclay Posted January 26, 2009 Share Posted January 26, 2009 Massive articulation = rubbing Massive tyres = rubbing Massive articulation and tyres = kiss good by to your wheel arches. Its not just the height of the wheel arches, when articulated the top of the tyre on the compressed side moves sideways towards the center of the vehicle. Having tried on my own RRC and seeing others on the net I would advise that the Gwyn Lewis setup provides too much articulation for standard RRC and Discovery inner rear wheel arches. There are ways round this such as either chopping up the inner wheel arches (I like Orgasmic Farmer's solution ) or increasing the wheel back spacing, but both of these have there disavantages. Cutting up inner wheel arches or further increasing the back spacing were not practical options for me so I sold my 11" dampers off the rear and currently just using standard fronts on the gwyn lewis mounts untill I sort out just how longer damper I can conviently use and some springs to match them. Last time Off road I drove places that LRs with longer travel suspension didn't and winch places were longer travel suspension would have made a differeance. That was with tyres which measure (not claimed size) 33" by 11" with the track width increased by 80mm What are your priotrities? Quote Link to comment Share on other sites More sharing options...
upnover4x4 Posted January 26, 2009 Share Posted January 26, 2009 Good luck, 37" tyres snap bits for a pastime. My 90 has fedimas measuring about that & nothing but carnage. Ive been at turmoil trying to decide what to do strentghening the drive line & correcting the gearing. My conclusion has been 1.66-1 transfer box std ratio 3.54-1 diffs arb or 4 pinned & am going to treat myself to an underdrive which is massively expensive but when you look at the cost of 4.75-1 crown &pinnion at 275 each cost is getting up on them. Quote Link to comment Share on other sites More sharing options...
upnover4x4 Posted January 26, 2009 Share Posted January 26, 2009 One other thing Ive got the extreme kit, works superbly but it came at a good price 2nd hand & I wish i had bought gwyns suspension for the minimal comparative outlay Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 26, 2009 Share Posted January 26, 2009 Won't an underdrive just massively increase the ease with which you can snap bits? Portals of some description would kill two birds with one stone - stronger, more clearance with no lift, and they'd drop the gearing too. Mog ones would probably work out similar money to strengthening the Rovers all in. Quote Link to comment Share on other sites More sharing options...
plasticbadger Posted January 26, 2009 Share Posted January 26, 2009 Won't an underdrive just massively increase the ease with which you can snap bits? Portals of some description would kill two birds with one stone - stronger, more clearance with no lift, and they'd drop the gearing too. Mog ones would probably work out similar money to strengthening the Rovers all in. Well put fridge. Underdrive basically multiplies torque, therefore multipling the load on the drive chain components down stream. That's one of the many advantages of portals - the down gearing is at the furthest point of the drive chain meaning all other components are subjected to less load. A portal swap is actually reasonably sensible once you get into huge tyres and huge lift. Mog 404 axles offer about 8" of portal drop, or lift. The problem is the down gearing in the portal box is in the region of 7:1 - my brother-in-law's 110 on Mog axles does 50 mph flat out, on 44" tyres. Also he's only running a 2" suspension lift and no body lift to 'clear' the 44s. Plenty of trimming though! clbarclay - how do smaller travel shocks help your tyre clearance? Wont they just limit down travel without limiting the critical up travel? Quote Link to comment Share on other sites More sharing options...
clbarclay Posted January 26, 2009 Share Posted January 26, 2009 Its not the upwards travel that was the problem, it was the inwards travel caused by the angle of the axle. To help explain here is a CAD model based on the geometry of a RRC. Note that this is a simplified model and doesn't take into account the effects of rear steer. The axle and tyres shown in green pivots around the star which represents the position of the A frame ball joint. The body is shown in red. This shows the model on 205r16 tyres, standard track width and the axle horizontal. The axle is then rotated around the ball joint untill the tyre touches the side of body, resulting in a maxium articulation of nearly 16 degrees. When I fitted the Gwyn Lewis mounts with RC dampers I was running 7.50-16 SATs on 11mm positive offset modulars. With the tyres and wheels changed the maximum articulation was increased to over 18 degrees. I didn't notice any innwer wheel arch rubbing issues while running the SATs Finally I got some Super Swamper LTBs on 8 sopke wheels with 7mm negative offset. Maximum articulation has been reduced to less than standard, despite the 80mm increas in track width. I hope this explains it for you. Quote Link to comment Share on other sites More sharing options...
plasticbadger Posted January 27, 2009 Share Posted January 27, 2009 Crikey, talk about comprehensive answer. That does explain it, I thought you meant clearance at the top of the arch, not on the inside face. My Landcruiser axle / wheel combo gives about 100mm increase in track width, so it isn't something I've come across, also because I've had to limit up travel due to the tyre diameter. Quote Link to comment Share on other sites More sharing options...
Escape Posted January 27, 2009 Share Posted January 27, 2009 Good luck, 37" tyres snap bits for a pastime. A lot depends on your right foot. I've been using 3" Mickey Thompson Competition Claws for the last 2 years, with ARBs, Ashcroft halfshafts and standard TD5 engine/gearing. Broke one HD CV, then upgraded those to Ashcroft as well and haven't had any problems since. I try and drive it sensibly, but have had moments with the front wheels up in the air and my foot down. Not cheap, but I have enough confidence in the set-up to take it out for a little greenlane around a big stinky puddle somewhere in Russia. Must admit I'm waiting for a set of Volvo's to arrive, but that has more to do with the car being a work in progress and always looking to improve. Quote Link to comment Share on other sites More sharing options...
clbarclay Posted January 27, 2009 Share Posted January 27, 2009 Glad that helped. I found out a while ago when trying to explain the change in front prop angles when lifted than simplified CAD models can be my more effective than just words. Like I says simplified I just realised that I got used the cross section width at the widest point for the LTBs rather than at the point where they rubbed at the corners of the tread which is slightly narrower. This worked out at 16.9 degrees. 1 degree better than standard, but 1.5 degrees worse than the SATs. Quote Link to comment Share on other sites More sharing options...
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