Engineering 35's ... the bad news

[Yom]

God forbid if we all have to drive on small tyres it may actually bring back a bit of driver skill. With track closures that are, and will go on, it may make some "lesser" tracks more of a challenge as well.

i do have to say it is getting annoying driving on otherwise flat ground and suddenly sinking into the ground because there's some 37" ruts beneath the dry crust.

having to pick a line on flat ground to prevent things like this happening is also quite annoying:

http://i103.photobucket.com/albums/m149 ... G_0264.jpg

That Mav was not going anywhere. Dora the Explorer stickers didn't help.

[bogged]

Watch all the tyre companies start pumping out 34's now! .

are you kidding? what just for the Aussie market, they will spend 100k's just to make 34's for our pissy little market

To clear up what Ed told me, he has Dualcab GQ. So it is a patrol talkin bout here. He was failed on a few bits (eg UHF Ariel on bullbar!) and then when he was home called engineer back to enquire about the tires to add on to the current 'certificate he was getting.

The engineer told him that the engineer was instructed that there is now no way to get 35's engineered (in this case patrol). The engineer is in Epping I believe? could be wrong, can find out if its important.

Ed has 35's in the shed, he thought he would do the right thing and get it engineered with them on. So hes going with 33's. For $66 more, why not.

I still think its up to interpretation of the rules. Unless they have been specifically told NO.

[booflux]

never understood this "engineering crap" so how do u engineer 35's? just write its ok and sign it? like wat do u do to make them ok on a 4wd?


im in qld btw.

The reason you don't understand is it is illegal in QLD. QLD rules on a solid axle 4x4 (F+R) are 25mm larger, no ifs, no buts, no engineer or mod plate required.

The NCOP if adopted in QLD will allow +50mm.

Actually your wrong re-read the ADRs which is what Qld follows at this point in time. Its no more than a 15mm increase in diameter regardless of IFS or solid axle. Track width increase is 50mm for solid and 25mm for IFS.

[sierrajim]

Is this the end for the Engineered vehicles at Tuff Truck??????

[joeblow]

Is this the end for the Engineered vehicles at Tuff Truck??????

they are engineered? ...........................

[v840]

Is this the end for the Engineered vehicles at Tuff Truck??????

They no longer have to be regoed so presumably they will not have to be engineered?

[Gwagensteve]

To the best of my knowledge, you can have a vehicle engineered for "offroad use only" which would ensure that it is soundly constructed. This might avoid the rule book having boggedybillion pages talking about grades of bolts, wall thicknesses, etcetcetc, and go some way to stopping massive bootyfab being entered and killing millions/marshalls/drivers etc. It should also prevent nasty arguments about bias or anything with scrutineers.

I honestly don't know what the current situation is though, but most the TT cars seem to be quite well constructed - probably moreso than a lot of road driven 4WD's.

However, AFAIK in the early years (2000?) cars had to be engineered registered and insured despite insurance being void for competition, and the competition equipment mandated in many cases voiding the engineers cert (non ADR harnesses, full cages etc)

Just some thoughts.

Steve.

[Fathillbilly]

Believe it or not it is up to the engineer’s discretion if a vehicle will pass or fail tyres, wheels, seats bla bla bla.

The NCOP are not a hard and fast nothing gets past this set of rules, if you build a vehicle that passes all test, and conforms to all relevant ADR's, you will get an engineers certificate.

I have been involved in this process and industry (vehicle building and modifying) for 20 years, and worked or have being personally involved in the engineering of hundreds of vehicles.

One last thing, if you get your vehicle engineered with 33" rubber, guess what size tyre you can run then 33"+2"=?

[Gwagensteve]

One last thing, if you get your vehicle engineered with 33" rubber, guess what size tyre you can run then 33"+2"=?

That's not the undertanding I have, but that might be due to engineers covering their ar$e.

Steve.

[ISUZUROVER]

never understood this "engineering crap" so how do u engineer 35's? just write its ok and sign it? like wat do u do to make them ok on a 4wd?


im in qld btw.

The reason you don't understand is it is illegal in QLD. QLD rules on a solid axle 4x4 (F+R) are 25mm larger, no ifs, no buts, no engineer or mod plate required.

The NCOP if adopted in QLD will allow +50mm.

Actually your wrong re-read the ADRs which is what Qld follows at this point in time. Its no more than a 15mm increase in diameter regardless of IFS or solid axle. Track width increase is 50mm for solid and 25mm for IFS.

Cheers.

The rim diameter may be varied from the standard size
but the overall diameter of the tyre must not vary by
more than +15mm or -26mm.

[Fathillbilly]

One last thing, if you get your vehicle engineered with 33" rubber, guess what size tyre you can run then 33"+2"=?

That's not the undertanding I have, but that might be due to engineers covering their ar$e.

Steve.

I'm not saying you will get the vehicle engineered.
But as the vehicle has been "re-complied" you can legally argue the point.

It was an engineer who told me this.

Yes they do tend to try and cover their ar$e$ quite a bit, and alot of the time if it is not written on a piece of paper, they will just say no.

[Wooders]

What a load of crap - by the logic of most of this thread it looks like all the semis on the road are now illegal

[Skegbudley]

What a load of crap - by the logic of most of this thread it looks like all the semis on the road are now illegal

Correct. Most of this tread contains dribble from people that have not read or have read NCOP and still have no idea.
According to NCOP. You will be able to increase tyre dia by 50mm WITHOUT an engineers approval.
Over this you will need a engineers certificate.
Nowhere does it say that you will not be able to engineer 35's on a full size 4WD like a patrol.

[Gwagensteve]

Skeg,

I do understand the NCOP, and I do understand the 50mm limit applies without engineer approval.

However, my understanding is that if 50mm of total other lift is exceeded, then an engineer's certificate is required, so 50mm for tyres=25mm of lift, so more than 25mm of other lift by body or suspension is the limit before enigneering is required.

Adittionally, getting an engineer to sign off >50mm of tyre is the problem - they don't generally want to sign off more than 50mm over the largest tyre for that axle without proof that the components on your axle are equal to those on another axle that is rated for a taller tyre.

Example - the wheelbearings and hub on a new Grand Vitara is the same as on an old grand vitara, but the new GV has a taller tyre.

If you prove to the engineer that the old GV hub is the same as the new one, then you could convince the eng. to pass the new GV tyre size on an old GV, but they are going to want to see a side by side comparison and take their own measurements to prove that beyond doubt.

The calculations required to prove a wheelbearing, for example, is strong enough for it's intended use (once a larger wheel/tyre is propsed) are daunting. Very few people would be willing to pay an engineer to perform them and no engineer will "experiment" and say "you should be OK"

Steve.

[AJ]

So what does this all add up to well the largest tyre on a patrol from factory is a 7.50-16, which some tyre manufactures are labelling as 235/85/16.

Stu

GU wagon series 1 handbook lists a 245/85R16 which is VERY handy.

[DIRTY ROCK STAR]

Is this the end for the Engineered vehicles at Tuff Truck??????

they are engineered? ...........................

mine is engineered for everything except the 42s. its engineered to run 37s legally though.

[rockcrawler31]

It's really not that hard guys.

I've got a coiled 75 in queensland. two sets of tyres, two sets of coils.

I run 36's and 5" off road and 32's and 2" on the road. an hours work if i know i'm going out for a play.

Why do you really need to run an expensive set of tyres on the road anyways?

[k3lst]

It's really not that hard guys.

I've got a coiled 75 in queensland. two sets of tyres, two sets of coils.

I run 36's and 5" off road and 32's and 2" on the road. an hours work if i know i'm going out for a play.

Why do you really need to run an expensive set of tyres on the road anyways?

Youve forgot that some of us have to drive from the big smoke 2 or so hours away just see some decent offroading, in which case we need to run those big tyres on road in front of the blue lights

[mmaaxx]

I undestand everyones concern here as we are always striving to amke our trucks bigger better and more capable.

Myself included.....but say like someone mentioned earlier, if 33 or 34" tyres were the maximum....then the tracks would be more driveable since there wouldnt be (you'd hope) a GQ on 37's ripping it up making it impassible for those on 33's.

if everyone had a 33 or 34 inch limit, it would take more skill to overcome obstacles, rather tha just relying on the bigger diamter tyre to get you through ruts.

I just want to thank some of you blokes for the info posted here, i didnt know that the engineer's look at the wheel bearing and hub strength when determining the largest tyres for a particular vehicle.

Is it possible to get a vehicle engineered where the wheel offset puts it out of the maximum allowable for an IFS vehicle?

Im 30mm over on each side of the hilux....(+30 stock to zero offset wheels)?

[Gwagensteve]

mmaaxx,

The "if everyone had smaller tyres" logic only holds if there's no erosion, winching etc.

The erosion creates ruts that lead to a desire for bigger tyres at least as often as someone with big tyres digs down to make a 35 or 37" tyred rut.

Also, - not everyone has the same sized diffs. It's been proved over and pver againt hat a small tyre and small diff equals the same clearance as a big diff with a big tyre.

I don't think a 37" tyre is big on a GU, especially one with a H260 rear diff. (legal or not - they don't end up woth much clearance under the diff) and it can still only dig 10" or so until it's diffed out. A hilux on a 33 will probab;y have more clearance and walk through the mess the 37" H260 GU made... and so would a sierra on 31's.

Recovery can also deepen ruts very quickly, and driving a small tyred car into an eroded rut is a sure method of chewing it all up in a messy recovery that creates a bigger problem than the undertyred car chould have based on it's tyres alone.

I am happy to admit that big tyres dig big holes, but big tyres also allow clearance that prevents having to get on it and dig up tracks in the first place. Driver behaviour is a big factor, but as someone who's been out there for over 15 years on tracks, I can't say the trand for big tyres is predominantly responsible for track damage.

We've idled our cars through holes (suzuki's on 31-35" tyres, on suzuki diffs) and then watched a convoy of patrols on 31's to 35's all hit the same hole at speed and drag each each other out for the next hour. I know which group caused the most damage.

Just some thoughts. I'm not really pushing a barrow except to say that there's a role for big tyres due to erosion, ledge size, rock traction quite apart from digging big holes that others can't drive.

[Gwagensteve]

an aside mmaaxx -

I'd be checking some part numbers. TRD Hiluxes ran a taller tyre than "normal" hiluxes, and additionally, I'd be interested to see if the hubs/bearings are the same between the hilux and LC100/L200.

I'd be guessing that with some clever parts number chasing and an sympathetic engineer, I'd bet you could cert a 34 on a current hilux without an unfeasible amount of work.

Steve.

[mmaaxx]

an aside mmaaxx -

I'd be checking some part numbers. TRD Hiluxes ran a taller tyre than "normal" hiluxes, and additionally, I'd be interested to see if the hubs/bearings are the same between the hilux and LC100/L200.

I'd be guessing that with some clever parts number chasing and an sympathetic engineer, I'd bet you could cert a 34 on a current hilux without an unfeasible amount of work.

Steve.

34's are my goal on my hilux, Im pretty sure with a bit more clever trimming I can get it to work...just got other expenses at the moment that stop me buying a 34" LTB or simex.

regarding the parts numbers, leave it up to me....Ill chase it up tomorrow.

and yes the TRD has a larger tyre, the equivalent of 30.5" over the sr5's 29" which if you argue right, you may get away with a small 285 that is only 32.5" diameter...something like a federal couragia which are small in their stated size, just to get the engineer certificate.

cheers.

[money_killer]

big tyres on the road are gay no need accept for WANK FACTOR

[Gwagensteve]

big tyres on the road are . no need accept for WANK FACTOR

What on earth does that mean? Where we drive in Vic are all "roads" as we don't have any private property parks, so to get where we are going we need to drive on roads.

Anyway, we're only talking 37 and under ATM so that's not "big"

Steve.

[weeman]

I cant believe this thread was even started, such a load of shit.

And all the answers/feedback are from an Instant message chat session.

For fuck sake, if there was statutory document stating it yeah i would believe it however as stu was saying speak to some decent engineers and anything is possible.

There are number of comp trucks which i would never have thought would be engineered are. They met the test so they also have coil over chassis extensions and i believe are either running 35s or 37s...

This whole thread is just a dribble of crap just to put the wind up people skirts

[Hoppy11]

My 35's and 15x 10's are engineered under the ICV rule, I can legally have 37's in WA, no swerve or brake test

[Gwagensteve]

load of shit.

This whole thread is just a dribble of crap just to put the wind up people skirts

Um, not it's not ALL dribble weeman

A) which state are you in?

B) what have you recently had engineered

(Serious questions)

I deal with club members engineering cars all the time in Victoria. Bogged is in victoria and my comments relate to my experience over some years in Victoria.

Yes, I've seen all sorts of garbage engineered in other states, in the past. I'm talking about the state of play, with multiple enigneers, in victoria, right now.

I'll stand by my original comments - 35's aren't impossible or prohibited on a patrol, just harder than many people could be bothered doing.

You'd be surprised what's possible if you're prepared to do the work.

Steve.

[k3lst]

big tyres on the road are . no need accept for WANK FACTOR

Youve forgot that some of us have to drive from the big smoke 2 or so hours away just see some decent offroading, in which case we need to run those big tyres on road in front of the blue lights

You should replies in future befre you post buddy

[weeman]

load of shit.

This whole thread is just a dribble of crap just to put the wind up people skirts

Um, not it's not ALL dribble weeman

A) which state are you in?

B) what have you recently had engineered

(Serious questions)

I deal with club members engineering cars all the time in Victoria. Bogged is in victoria and my comments relate to my experience over some years in Victoria.

Yes, I've seen all sorts of garbage engineered in other states, in the past. I'm talking about the state of play, with multiple enigneers, in victoria, right now.

I'll stand by my original comments - 35's aren't impossible or prohibited on a patrol, just harder than many people could be bothered doing.

You'd be surprised what's possible if you're prepared to do the work.

Steve.

Im in melbourne also.

I haven't had anything engineered because i don't see the point. I have not heard of anyone who has been done by running 35's on there patrol and i have been pulled up a number of times by the police and its never been questioned.

However about the engineering aspect of this conversation, yes there is a engineer from narre warren area that has engineered number of patrols and jeeps running 35's they were all at san down doing the swerve tests.

For people here to post that it cant be done and there is no possible solutions, is somewhat misleading. Yes i agree the rules are getting tighter however not to the point everyone that everyone has to sell there 35's.

And more to the point what is a true 35", as not all tyre are the same just because they placarded with 35 on the sidewall does not mean they are to a set size, and i doubt the cops or testers would be walking around with a tyre gauge to check the measurements.

[Gwagensteve]

Engineers use the tyre and wheel association handbook for what equals a certain size, both in relation to what you want to run and what's on your car now.

You can't say "I only want to run bald 35's on my patrol and they're 34" tall so that's OK" or "I run short 35's"

No, I know you're unlikely to get measured, and that SLA makes a huge difference (Static Loaded Radius) but rules are rules.

Steve.