Different Tyres Front & back?

Submitted: Friday, Mar 17, 2006 at 17:32
ThreadID: 31847 Views:3074 Replies:7 FollowUps:2
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Are there any major issues if a less aggressive tread pattern is on the front compared to the back of the vehicle ?
eg If Cooper STs on back and say ATRs on the front (of same diameter).
Equally are there any good reasons for doing so? eg better road handling or better traction on sand.
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Reply By: BenSpoon - Friday, Mar 17, 2006 at 19:40

Friday, Mar 17, 2006 at 19:40
I'd stick the more aggressive ones at the front- you need more traction up there as they do the vast majority of the work- turning, braking, climbing. It helps keep away from aquaplaning too if you have plenty of good tread. The back round things are just passengers along for the ride.
AnswerID: 161211

Follow Up By: Member - Davoe (Widgiemooltha) - Friday, Mar 17, 2006 at 20:16

Friday, Mar 17, 2006 at 20:16
Spotted - a lifted 80 series roof racks with heaps of arials and an EO sticker between the Kambaldo Turnoff and Widgie around 5.00pm thurs Arvo, Any ideas?
FollowupID: 415977

Follow Up By: BenSpoon - Monday, Mar 20, 2006 at 10:56

Monday, Mar 20, 2006 at 10:56
Our radio emergency channel and the refuge chamber phones went down at the same time so I had to run down there quick- There was no company cars left to do the run from Kal to Norsey so I had to drive my own. $110 of fuel each time...
FollowupID: 416359

Reply By: Gerhardp1 - Friday, Mar 17, 2006 at 20:12

Friday, Mar 17, 2006 at 20:12
If cars or 4WDs handled better with different tyres front and back, you would be able to buy them new like that. You can't, and it's for a very good reason.

Front and rear tyres are equally important, contrary to some opinion, and should always have the same level of grip. That's the reason for tyre rotation - to keep things as even as possible.

For better traction on sand, let your pressures down. For better road holding on bitumen, keep your pressures up. For trail work, somewhere in between.

Let's assume you have a vehicle that has neutral handling when fitted with correct tyres, and you do mix your tyres with more aggressive tyres on the rear, you will find yourself spinning when you didn't want to because you will have created oversteer. If you put them on the front, you will create understeer which will be safer but could see you go straight ahead at roundabouts as soon as there is a sprinkle of rain.

In summary, don't do it. Better still, DON'T DO IT - it could be me you crash into.

AnswerID: 161220

Reply By: Philip A - Friday, Mar 17, 2006 at 20:13

Friday, Mar 17, 2006 at 20:13
Gee that must be why trucks have the traction tyres on the front wheels and the steering ones on the back.
Seriously though, going uphill about 80-90% of the traction is supplied by the back tyres so the obvious solution is to put the traction tyres on the back.
I had a mix of BFG AT on the front and BFG MT on the back of my Rangie.
Only downside was slight oversteer tendency at speed on curves on bitumen, and need to be careful on wet roads as more grip on front. But much better steering and quieter also. i believe that I got about 90% of the benefit of muds with about 30% of the downside.
Regards Philip A
AnswerID: 161221

Reply By: Crackles - Friday, Mar 17, 2006 at 20:20

Friday, Mar 17, 2006 at 20:20
Not normally done on the family 4x4 and I haven't heard of any real benefits in doing so but on mid to large 4x4 trucks used mostly onroad we often run an agressive tread on the rear duals & an intermediate tyre on the front to minimise the stepping of the lugs, common on heavy vehicles. The loss in traction is far outweighed by the improved steering, road holding & tyre wear.
Cheers Craig...........
AnswerID: 161223

Reply By: Scubaroo - Friday, Mar 17, 2006 at 21:40

Friday, Mar 17, 2006 at 21:40
One point to consider having different tread patterns is the slightly different diameter and wear rates, and what this might do to your 4WD system - I had new BFG ATs on the front of the Pajero, and worn ATs on the back - basically disabled the ability to switch from 2WD/4WD on the fly - I had to pull over and reverse to get 4WD to disengage. Basically the 4WD engagement / disengagement mechanism relies on 4 equal tyres being fitted - I think the difference was causing some tension wind-up. Resolved it by moving the worn tyres to the front - wind-up problem went away. Probably still happening, but it's not affecting the 2WD/4WD switch anymore.

The difference in tread depth was about 7mm - that's a 14mm diameter difference between two otherwise identical tyres.
AnswerID: 161243

Reply By: Patrolman Pat - Friday, Mar 17, 2006 at 21:55

Friday, Mar 17, 2006 at 21:55
I'm just wondering what spare you'd carry.
AnswerID: 161245

Reply By: Rob Ackland - Monday, Mar 20, 2006 at 13:46

Monday, Mar 20, 2006 at 13:46
The simplest question you have to answer is if it is legal. I suspect you will find that any local motor registration authority will have a clear opinion that you must have the same tyres all round on any vehicle. Equally your insurance company may have a similiar view.

Apart from the simple legal aspects there is no real benefit. Take a look at any competition 4WD for a start. If there was any real benefit it would be this group exploring the limits and they don't. Ask yourself how many spares you want to take on a trip if you are running different tyres on different axles.

Well driven, with good driving skills and the right tyre pressures will get most 4WD's almost anywhere. It's getting from trouble back to safety that takes some thinking about.

AnswerID: 161680

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