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Posted: Sun Oct 11, 2009 6:00 pm
by andrew91
my stopping distance was pretty shithouse before but that's why I upgraded the brakes.. didn't do a gq conversion but I hope to eventually but with new rotors, drums and qfm 500 degree pads and shoes I can lock all 4 wheels in the dry so I'm reasonably happy with the brakes for the moment.
chimpboy I didn't mean to be an ass but to answer your question no I dot drive eratically. I bought the Hilux because I knew it had no power and I drive it well within it's limits. I'm not happy with the steering and plan to upgrade to a hi steer to try take out some of the slack and the new steering box that would all be part of the process would not be astray neither. I am far from a hoon but I do enjoy getting a fair bit muddy when I can.
yes the cops had fair go on the tail lights and I had all intention of changing them. but on my wages LED tail lights wherent quiet within my immediate budget but now I have them. the mudflaps and flares I didn't particularly know about but I did plan on putting flares on. and I definetly didn't feel comfortable driving one on a collapsed wheel bearing but what can you do? I kept to backstreets and kept under 60k but other than that short of getting a tow which isn't really necessary for a 20k drive whatta you do?
I didn't mean to have a go at anyone and I try not to be arrogant but don't stereotype all p players as clueless hoons. I drive well within the law and the abilty of my car and I know it's limitations.
anyhow thanks for all the info. I wasn't particularly planning on HID's because I didn't like the fact that they take a while to warm up but I'll look into upgrading my lightforcers soon.
thanks all
Posted: Sun Oct 11, 2009 6:04 pm
by chimpboy
Fair enough, if I went too grumpy old man on you and stereotyped you as reckless, I apologise.
If you've done all that you should be able to get it (mostly) engineered and it's probably worth it.
Posted: Sun Oct 11, 2009 6:26 pm
by dirtyGQ
-Scott- wrote:dirtyGQ wrote:chimpboy wrote:So how's your stopping distance with the 35s?
I have 36.8's on mine and really have to ask you WTF r u on about ???????
Listen very carefully, I shall say zis only once.
(I'm presuming you're talking about a GQ, because of your username. If your vehicle is street legal with 36.8s, then none of this applies.)
In Queensland you CAN NOT engineer larger tyres on a production vehicle. (I am not talking about ICVs.)
If your 36.8" tyres are on a GQ they are not road legal in Queensland. They are more than 10% larger than the factory tyres, and have both increased the load on your brakes (increased polar moment of inertia of the tyres) and decreased the effectiveness of your brakes (reduced the ability of your brakes to apply a decelerating force.)
Barring exceptional circumstances, if you run into the rear of somebody else, you are automatically considered to be at fault. The bills will come to you.
If your insurance company notices your illegal tyres, which simple physics will prove have compromised your braking ability, it is easy for them to conclude that your defect was a significant contributor to the accident, and deny your claim. That will most likely place you in a world of pain.
I suspect that is WTF chimpboy is on about.
Simple physics explain how my braking distance is increase ........ well explain. I have had one at fault claim in 9 years in my patrol and braking distance was not compromised due to tyre size ...... i might be a little short of intelect so please explain why my braking distance would be compromised due to my humungous people squashing tyres ?????? Brake upgrades etc ,now stops better than ever . I am sure with these dark age laws in qld i could find some illegal mods on most 4wd's if not all vehicles.
Posted: Sun Oct 11, 2009 6:26 pm
by dirtyGQ
-Scott- wrote:dirtyGQ wrote:chimpboy wrote:So how's your stopping distance with the 35s?
I have 36.8's on mine and really have to ask you WTF r u on about ???????
Listen very carefully, I shall say zis only once.
(I'm presuming you're talking about a GQ, because of your username. If your vehicle is street legal with 36.8s, then none of this applies.)
In Queensland you CAN NOT engineer larger tyres on a production vehicle. (I am not talking about ICVs.)
If your 36.8" tyres are on a GQ they are not road legal in Queensland. They are more than 10% larger than the factory tyres, and have both increased the load on your brakes (increased polar moment of inertia of the tyres) and decreased the effectiveness of your brakes (reduced the ability of your brakes to apply a decelerating force.)
Barring exceptional circumstances, if you run into the rear of somebody else, you are automatically considered to be at fault. The bills will come to you.
If your insurance company notices your illegal tyres, which simple physics will prove have compromised your braking ability, it is easy for them to conclude that your defect was a significant contributor to the accident, and deny your claim. That will most likely place you in a world of pain.
I suspect that is WTF chimpboy is on about.
Simple physics explain how my braking distance is increase ........ well explain. I have had one at fault claim in 9 years in my patrol and braking distance was not compromised due to tyre size ...... i might be a little short of intelect so please explain why my braking distance would be compromised due to my humungous people squashing tyres ?????? Brake upgrades etc ,now stops better than ever . I am sure with these dark age laws in qld i could find some illegal mods on most 4wd's if not all vehicles.
Posted: Sun Oct 11, 2009 6:39 pm
by -Scott-
dirtyGQ wrote:-Scott- wrote:dirtyGQ wrote:chimpboy wrote:So how's your stopping distance with the 35s?
I have 36.8's on mine and really have to ask you WTF r u on about ???????
Listen very carefully, I shall say zis only once.
(I'm presuming you're talking about a GQ, because of your username. If your vehicle is street legal with 36.8s, then none of this applies.)
In Queensland you CAN NOT engineer larger tyres on a production vehicle. (I am not talking about ICVs.)
If your 36.8" tyres are on a GQ they are not road legal in Queensland. They are more than 10% larger than the factory tyres, and
have both increased the load on your brakes (increased polar moment of inertia of the tyres) and decreased the effectiveness of your brakes (reduced the ability of your brakes to apply a decelerating force.)
Barring exceptional circumstances, if you run into the rear of somebody else, you are automatically considered to be at fault. The bills will come to you.
If your insurance company notices your illegal tyres, which simple physics will prove have compromised your braking ability, it is easy for them to conclude that your defect was a significant contributor to the accident, and deny your claim. That will most likely place you in a world of pain.
I suspect that is WTF chimpboy is on about.
Simple physics explain how my braking distance is increase ........ well explain. I have had one at fault claim in 9 years in my patrol and braking distance was not compromised due to tyre size ...... i might be a little short of intelect so please explain why my braking distance would be compromised due to my humungous people squashing tyres ?????? Brake upgrades etc ,now stops better than ever . I am sure with these dark age laws in qld i could find some illegal mods on most 4wd's if not all vehicles.
Posted: Sun Oct 11, 2009 6:40 pm
by -Scott-
-Scott- wrote:dirtyGQ wrote:-Scott- wrote:dirtyGQ wrote:chimpboy wrote:So how's your stopping distance with the 35s?
I have 36.8's on mine and really have to ask you WTF r u on about ???????
Listen very carefully, I shall say zis only once.
(I'm presuming you're talking about a GQ, because of your username. If your vehicle is street legal with 36.8s, then none of this applies.)
In Queensland you CAN NOT engineer larger tyres on a production vehicle. (I am not talking about ICVs.)
If your 36.8" tyres are on a GQ they are not road legal in Queensland. They are more than 10% larger than the factory tyres, and
have both increased the load on your brakes (increased polar moment of inertia of the tyres) and decreased the effectiveness of your brakes (reduced the ability of your brakes to apply a decelerating force.)
Barring exceptional circumstances, if you run into the rear of somebody else, you are automatically considered to be at fault. The bills will come to you.
If your insurance company notices your illegal tyres, which simple physics will prove have compromised your braking ability, it is easy for them to conclude that your defect was a significant contributor to the accident, and deny your claim. That will most likely place you in a world of pain.
I suspect that is WTF chimpboy is on about.
Simple physics explain how my braking distance is increase ........ well explain. I have had one at fault claim in 9 years in my patrol and braking distance was not compromised due to tyre size ...... i might be a little short of intelect so please explain why my braking distance would be compromised due to my humungous people squashing tyres ?????? Brake upgrades etc ,now stops better than ever . I am sure with these dark age laws in qld i could find some illegal mods on most 4wd's if not all vehicles.
Posted: Sun Oct 11, 2009 9:08 pm
by zuffen
The Insurance company needs to prove the tyres caused the accident.
This is not "black and white".
I ran an insurance organaisation for almost 20 years that specialised in modified cars so I know the law.
If the tyres didn't cause oe contribute in major way the claim will have to be paid.
Posted: Sun Oct 11, 2009 10:04 pm
by -Scott-
zuffen wrote:The Insurance company needs to prove the tyres caused the accident.
This is not "black and white".
I ran an insurance organaisation for almost 20 years that specialised in modified cars so I know the law.
If the tyres didn't cause oe contribute in major way the claim will have to be paid.
I agree 100%.
I was basically playing devil's advocate, that the large tyres (under some circumstances, such as the scenario I posted) could give the insurance company an excuse to deny the claim. They could be challenged in court, and the onus of proof would be on the insurance company, but this would be (for most people) a painful experience.
Posted: Mon Oct 12, 2009 7:50 am
by KiwiBacon
I really wish people would stop stating rotational weight and polar moment as reasons bigger tyres are harder to stop.
They're harder to stop because they're bigger diameter, they take more torque at the brakes to provde the same stopping force on the road. Rotating weight and polar moment factors are small enough to be ignored completely.
The decrease in your brakes effectiveness is directly related to size increase. 10% taller and you've got 10% less maximum braking force.
Posted: Mon Oct 12, 2009 8:09 am
by rockcrawler31
Barnsey wrote:bogged wrote:andrew91 wrote:does anyone know the law with spotties? as in are roof mounted ones illegal, and do they need to be within a certain distance of the ground, how many etc?
Just buy 2 good quality spotlights, and you wont need 1200 hanging off everywhere. Put some HID kits off ebay in them if you feel you need.
X infinity
Never seen the point in roof mounted spotties, unless they're the pivot type for hunting.
Ok where do i start
Increased light throw off road, illuminating holes and whathaveyou better than down low
most importantly for my car
less obstacles in the way of a radiator that is marginal in size from factory as it is, then has a turbo strapped to it. So far better cooling characteristics.
while you have to be carefull of overhanging branches off road, less chance of a stone destroying the lens on the road from the car in front.
no back glare off the bullbar, mine are place far enough back to not get any off the bonnet either before you mention it.
Like you have pointed out before it's personal preference depending on what your needs are. It doesn't make either of us more right or wrong. It's like the mack truck bullbars on commonwhores. I think they're over the top and wanky and trying to be something they're not when a smaller one will do the job, but if it's what they want then i guess that's their choice.
Posted: Mon Oct 12, 2009 8:15 am
by rockcrawler31
KiwiBacon wrote:I really wish people would stop stating rotational weight and polar moment as reasons bigger tyres are harder to stop.
They're harder to stop because they're bigger diameter, they take more torque at the brakes to provde the same stopping force on the road. Rotating weight and polar moment factors are small enough to be ignored completely.
The decrease in your brakes effectiveness is directly related to size increase. 10% taller and you've got 10% less maximum braking force.
i thought it was a leverage thing too, same reason it accelerates like a slug and breaks components. If there was no difference to braking at all, can someone explain why mine brakes like it's on ice with 37's? (off road only of course)
Posted: Mon Oct 12, 2009 10:46 am
by Athol
Yes, it is the leverage ratio between the effective diameter of the brake caliper and the effective diameter of the tyre. Change the tyre diameter and you're changing the ratio.
This was specifically the reason why the "Manager, Investigations and Compliance" at the NSW RTA decided to allow only up to 2" diameter increase over standard before requiring an abridged brake test. A percentage might have been more technically correct, but they chose a nice easy round number.
A different person within the same department suggested that there was also an issue with increased unsprung mass making handling worse, but some 35" tyre combos are lighter than original split rims...
Posted: Mon Oct 12, 2009 11:48 am
by dogbreath_48
Athol wrote:Yes, it is the leverage ratio between the effective diameter of the brake caliper and the effective diameter of the tyre. Change the tyre diameter and you're changing the ratio.
This was specifically the reason why the "Manager, Investigations and Compliance" at the NSW RTA decided to allow only up to 2" diameter increase over standard before requiring an abridged brake test. A percentage might have been more technically correct, but they chose a nice easy round number.
A different person within the same department suggested that there was also an issue with increased unsprung mass making handling worse, but some 35" tyre combos are lighter than original split rims...
r.e. Braking test.
Do the brakes have to peform as well as a standard vehical of the same year/model, or is there another benchmark that they have meet?
Posted: Mon Oct 12, 2009 12:08 pm
by Chucky
[quote="KiwiBacon"]I really wish people would stop stating rotational weight and polar moment as reasons bigger tyres are harder to stop.
They're harder to stop because they're bigger diameter, they take more torque at the brakes to provde the same stopping force on the road. Rotating weight and polar moment factors are small enough to be ignored completely.
The decrease in your brakes effectiveness is directly related to size increase. 10% taller and you've got 10% less maximum braking force.[/quote]
This is also wrong, braking is effected by larger tyres, but it's not as linear, or a sever as you are saying.
In reality, ensuring you have good brake system (booster, calipers and solid brake lines, no ballooning rubber lines etc) and good brake pads and you can easily brake a 35" or even bigger tyre.
Remember, the brake systems are designed to brake a hilux, fully loaded, towing a trailer fully loaded to it's max towing cap.
Posted: Mon Oct 12, 2009 12:14 pm
by KiwiBacon
Chucky wrote:This is also wrong, braking is effected by larger tyres, but it's not as linear, or a sever as you are saying.
In reality, ensuring you have good brake system (booster, calipers and solid brake lines, no ballooning rubber lines etc) and good brake pads and you can easily brake a 35" or even bigger tyre.
Remember, the brake systems are designed to brake a hilux, fully loaded, towing a trailer fully loaded to it's max towing cap.
Simple physics, 10% bigger tyres require 10% more brake torque to stop as hard. Yes it's completely linear.
25% bigger tyres need 25% more braking torque to stop as hard.
A hilux at max load with a trailer at max load would be a pretty poor measure of braking performance.
Posted: Mon Oct 12, 2009 1:23 pm
by Athol
dogbreath_48 wrote:Do the brakes have to peform as well as a standard vehical of the same year/model, or is there another benchmark that they have meet?
The ADR (31 or 35 depending on vehicle category) specifies minimum rates of deceleration for various loading conditions. The abridged test is for a fully loaded vehicle (ie at GVM). If the stock vehicle passed the requirements easily, the bigger tyres might pass even though their results were inferior to the stock vehicle.
Posted: Mon Oct 12, 2009 3:14 pm
by PCRman
KiwiBacon wrote:Chucky wrote:This is also wrong, braking is effected by larger tyres, but it's not as linear, or a sever as you are saying.
In reality, ensuring you have good brake system (booster, calipers and solid brake lines, no ballooning rubber lines etc) and good brake pads and you can easily brake a 35" or even bigger tyre.
Remember, the brake systems are designed to brake a hilux, fully loaded, towing a trailer fully loaded to it's max towing cap.
Simple physics, 10% bigger tyres require 10% more brake torque to stop as hard. Yes it's completely linear.
25% bigger tyres need 25% more braking torque to stop as hard.
A hilux at max load with a trailer at max load would be a pretty poor measure of braking performance.
Just to clear this up. When working in a single plane.
Torque = Force X distance.
Solving this for Force we get
Force = Torque / Distance
Lets say that your brakes can apply 10Nm of torque (just for convenience I don't know how much torque brakes can apply) in the opposite direction to travel (hence stopping). Lets also say your 35" tyres have a radius of 0.4445m. This means that Force is 10Nm / 0.4445m or 22.4971879 Newtons. No if we go to a tyre that is 10% bigger we have a 38.5" we have a radius of 0.48768m. Doing the same equation we have 10Nm / 0.48768m = 20.5052493 Newtons.
((20.5052493-22.4971879)/20.5052493) X 100 = -9.71428619 or close enough to a 10% drop when the effect of rounding is included.
I'm not saying that the entire braking system is this simple but when you have an equation with three parts and one is constant the other two are always in proportion (either inverse or direct). What simple physics IS saying is that IF you increase your rolling diameter for the same counter-torque applied at the brake you WILL have less force at the tread to counteract your forward momentum. This means that for the same amount of Force on the brake you WILL take longer to stop, UNLESS you push down harder on the brake thus applying more force. Or if you have already exceeded you braking systems maximum force and the back of that truck is STILL coming at you may have problems.
Posted: Mon Oct 12, 2009 8:44 pm
by -Scott-
As Athol has noted, abridged braking tests aren't so much about determining ultimate braking performance as about determining whether brake performance is acceptable.
If the test has been performed on your vehicle (by a qualified person) and judged to be acceptable, you're good.
If the test hasn't been performed, and your insurance company decides to try you on, you'll need to fight them on a legal battle field.
In dirtyGQ's case, his tyres cannot be engineered in Queensland, so his brakes weren't tested as part of that engineering process.
However, he has since indicated that he has uprated his brakes. If he has had a braking test performed on his larger tyres, and passed, I would say he has a defensible position.
As for the actual impact of the other factors I listed, I don't know how much analysis an insurance assessor will perform before deciding to deny a claim. If he/she should decide to deny the claim, the decision must be challenged, and could end up in court.
The probability of this happening? Not sure, and not really concerned - now that my tyres are engineered.
When I was in Queensland the same tyres weren't engineered, I was aware of the risks, and I accepted them.
Not all members on this forum are aware of the risks (however big they are) they run with their larger tyres.
Posted: Tue Oct 13, 2009 4:31 pm
by dogbreath_48
Athol wrote:dogbreath_48 wrote:Do the brakes have to peform as well as a standard vehical of the same year/model, or is there another benchmark that they have meet?
The ADR (31 or 35 depending on vehicle category) specifies minimum rates of deceleration for various loading conditions. The abridged test is for a fully loaded vehicle (ie at GVM). If the stock vehicle passed the requirements easily, the bigger tyres might pass even though their results were inferior to the stock vehicle.
Thanks for the info
Posted: Wed Oct 14, 2009 5:10 pm
by +dj_hansen+
andrew91 wrote:does anyone know the law with spotties? as in are roof mounted ones illegal, and do they need to be within a certain distance of the ground, how many etc?
To be honest mate... i think you need to have a good read off the relevent documents found in this link which should answer all your questions.
http://www.vicroads.vic.gov.au/Home/Rul ... formation/
Once upon a time you could get away with no mud flaps, small flares, and 35's with mud everywhere, sadly those days are gone, just like i never got to legally play with firecrackers. If you wont to have as much fun with your new truck, atleast make it look like your car complys with the standards above
Remember,
Mud flaps can be unbolted for offroad use, same with flares, light bars etc
Good tech Athol!