Thread: driveline questions

The formula is easy

Reliability = $$$$

Regards
Max P

Originally Posted by Tusker

The formula is easy

Reliability = $$$$

Regards
Max P

LOL

I like that

You'll be OK with your set up Mat.
You don't have all that V8 power that Mick has under his right foot .


I think you'll find Micks situation was a bit extreme. He was towing a very unco-operative Patrol uphill through a very rough section of track.
Something eventually gave & it just happened to be the diff in this case. It could quite easily have have been an axle.
The tyres might have contributed by gripping the track very well & preventing wheel spin but I doubt the size factor played a part in the diff failure.

Originally Posted by dobbo

I've been having a think since seeing the photo's of CAL415's destroyed dif and have been wondering how much stress does fitting oversized tyres put on a standard differential and driveline components. Does anyone know the a formulae to work out the best tyre size to get the best overall combination between the reliabilty of standard sized tyres and the offroad ability of the oversized tyres.

I like the advantages of running with larger tyres offers, but do not want the expense and hassles of destroyed differentials and other components

What is the happy medium?

mate ive seen Tdi discos running 31/10.5/15,s blow diffs

yes your standard diff is poo id update

i did 3 rear diffs in one year in my old rangie then i found jmac in melb oh it was heaven from then on

and now i have the universe its called salisbury with a locker + Defender

Even the biggest usual tyre size upgrade is only about 10% larger in radius than standard, so the increase in stress on the driveline from the larger tyres is only in the same proportion. Any increase in tyre grip increases the possible stress, and although this grip is independent of tyre diameter, those who increase tyre size usually seek to increase grip as well.

Failures are usually caused by impact loads, when the tyre is slipping and then grips suddenly, and larger tyres may increase the frequency of this because the higher unsprung weight makes it harder to keep the wheels in contact with the ground.

But probably the major reason for the association of larger tyres with driveline failures is simply that people who go for oversize tyres are often (usually?) the same people who drive in a manner likely to result in driveline failure.
John

Originally Posted by rangieman

mate ive seen Tdi discos running 31/10.5/15,s blow diffs

yes your standard diff is poo id update

i did 3 rear diffs in one year in my old rangie then i found jmac in melb oh it was heaven from then on

and now i have the universe its called salisbury with a locker + Defender

3 diffs in 1 year . Is that driving style or V8 powers fault?

Hmmm yeah. A 10% bigger tyre weighs a lot more than 10% more.

If you're sensible when you drive it and have mechanical empathy then generally you'll be ok - but big tyres with big grip and big weight are hard on the driveline when they spin and then grab - which breaks and twists things.

I ran 33's on standard (24spline) gear for ages, including Simexs, but a lot of stick and a lot of stupidity did the trick in breaking it, but it took a bit.

Originally Posted by mns488

3 diffs in 1 year . Is that driving style or V8 powers fault?

Thats time to fork out for a maxidrive!!!!