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  #51  
Unread 1st October 2018, 08:30 PM
Beachworm Beachworm is offline
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Quote:
Originally Posted by Rally View Post
Point is that tyres make only a minor difference to off road ability compared to diffs. By having better diffs with good road tyres you have a more capable car on road and more capable off road. Win win.

Both cars were turbos. Both cars were aired down. A welded diff would be as effective off road as a locker, until something broke. And a nightmare on road. Yes the SH made it up, more due to the driver than anything else. And not without cutting up the track even more.
I'd love to have a locked diff but I don't think you've proven your point about tyres. On the dry, loose surface you were on the tyre compound would be more significant than the tread pattern. What you need is two cars, identical bar for different tyres to do the same run. Then you would have a valid comparison of tyres.

I would be very surprised if your road tyres would get you the same distance as KO2 tyres uphill in muddy conditions given all other things were equal.

In most dry circumstances in Australia tread pattern makes only a small amount of difference. On sand, there is no doubt that road tyres work better. The true advantage of AT tyres is in their construction and the benefits that offers in rough conditions.

Firstly, additional sidewall strength reduces the risk of damage from sharp rocks, roots etc. I have personal experience of tearing a great chunk out of the sidewall of a road tyre while competing in a rally. An instant flat is the result and that's the last thing you want on a steep climb. It's often very difficult to get the car somewhere a wheel can be changed when one tyre is flat. Having it happen at speed is another story.

Secondly, most people who fit AT tyres go for a higher profile that allows running greatly reduced pressures without losing so much ground clearance as with standard road tyres.

Thirdly, but not last by any means is the ability to run AT tyres at reduced pressure for extended periods of time with less risk of overheating the sidewalls resulting in tyre failure.

I do some beach driving and some bush driving. Although road tyres would work as well, or better on the sand for short runs, They have distinct advantages on other terrain or over long distances at low pressure. In my opinion, a set of good AT tyres is a much more practical investment than a locker in the first instance. ( I still want a locker, but AT tyres come first because I can afford them and they don't cost more than my car is worth)
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  #52  
Unread 2nd October 2018, 12:25 AM
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Rally Rally is online now
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You assume all all terrain tyres are equal when they aren’t. Sure. The ko2 has stiff sidewalls but many other all terrains don’t and have thinner sidewalls than my road tyres. Maybe the KO2 will go a bit further though you will have to put up with a lot less grip elsewhere for the tiny numbers of opportunities to use that slight advantage. Yes, the taller tyre has advantages yet these work against you on bitumen where most cars are found, even ones considered an off road car.

The video clearly shows that diffs are more important than tyres. For it to be otherwise, then the SH would not have struggled
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  #53  
Unread 2nd October 2018, 01:39 AM
Beachworm Beachworm is offline
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Quote:
Originally Posted by Rally View Post
You assume all all terrain tyres are equal when they arenít. Sure. The ko2 has stiff sidewalls but many other all terrains donít and have thinner sidewalls than my road tyres. Maybe the KO2 will go a bit further though you will have to put up with a lot less grip elsewhere for the tiny numbers of opportunities to use that slight advantage. Yes, the taller tyre has advantages yet these work against you on bitumen where most cars are found, even ones considered an off road car.

The video clearly shows that diffs are more important than tyres. For it to be otherwise, then the SH would not have struggled
What the video actually shows is that an SG turbo manual with road tyres and diff lock will climb better on loose gravel and rocky terrain that a stock SH turbo auto with KO2 AT tyres.

If you want to try to prove that a diff lock is more important than AT tyres you need to have two sets of tyres for your car and run the same section of track on the same day using the same lines at the same speed. Even then you can't prove that the diff is more important than the tyres. You can only prove which combination gave you the best performance under that specific set of circumstances.

I have no doubt that you will be able to prove that a car with a locked diff and road tyres will get you further than the same car on AT tyres and no locked diff.

I would be surprised if you couldn't also prove, using the appropriate scientific method, that a locked diff is superior to VDC.

I am not arguing that AT tyres are more important than a locked diff. I am making the point that if someone is setting up a car for off-road use it is more logical, as one of the first steps, to spend a small amount of money on AT tyres ( the cost is minimal if you have to fit a new set of tyres anyway) than a large amount of money on a locked diff.

My car spends 90% of its time on bitumen and my good quality AT tyres with tough sidewalls don't perform as well as my old road tyres and I knew that would be the case. AT tyres, like nearly every other modification you can make for off-roading will be a compromise between performance off-road and performance on-road. As long as you know what to expect it isn't a problem. I couldn't justify spending more than my car is worth on a modification for off-roading when my AT tyres were actually cheaper than good quality road tyres.
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  #54  
Unread 2nd October 2018, 12:17 PM
MiddleAgeSubie MiddleAgeSubie is offline
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I think pretty much everyone other than Rally agrees
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Last edited by Kevin; 3rd October 2018 at 11:38 AM. Reason: Unnecessary use of Quote
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  #55  
Unread 2nd October 2018, 02:46 PM
scalman scalman is offline
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actually street tires are pretty good on sand or sandish road. on stones they can be not bad too. and street tires wont dig up down so much as more agressive tires would. important thing is what everyone finds work best for him and thats fine. Rally just dont need rally tires at all.
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  #56  
Unread 3rd October 2018, 12:03 AM
Beachworm Beachworm is offline
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Quote:
Originally Posted by MiddleAgeSubie View Post
I think pretty much everyone other than Rally agrees
I understand where Rally is coming from. The locker has been his project and is probably the most significant development of an off-road aid that I've ever heard of in Subaruland. I'd love to have one in my car too. If I win Lotto, I'll be contacting Rally to see how I go about getting one.

I acknowledge that he has also demonstrated that, under some conditions, road tyres are as good, or better than AT tyres.

I believe, however, that good quality AT tyres are the best all-round compromise as the first improvement for a Subaru when more than gentle off-road trips are planned through a wide variety of environments, a locker is something that could be considered after tyres, underbody protection, suspension modifications etc. have been done.

Credit where credit is due: Rally has done all of this except for the AT tyres.
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  #57  
Unread 3rd October 2018, 04:49 AM
scalman scalman is offline
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Imagine places Rally could go with ko2 tires and lockers, more lift and cut bumpers. Lol but if he dont need it he dont need it. Stuborn people like myself knows best.
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