255/70/16 vs 245/75/16 KM2's for a P38 - First post :)

[UK_P38]

Firstly, hello! I have just bought a 2001 P38 that I plan to use daily but also want to make a few mods for weekend off roading. Starting with tyres and the Faskit EAS emergency kit.

After much research I got my tyre choice split between these two sizes. In reality will the extra 10mm in diameter of 245/75 make any reasonable difference over 10mm extra width of the 255/70 especially considering tyre wear after a few 1000km's.

Going for the BF Goodrich KM2's

Is the light truck rating on the 245/75/16 purely based on the size?

[Keithy P38]

Welcome to the forum mate!

A good thread to talk about! There have been multiple topics raised over tyre sizes on our beloved's! Each to their own with sizes though (search function is your friend)! We have a few P38's running KM2's here. Mine is one, on the 255/70's. another I'm aware of on 265/75's and Paul on 255/85's! May even be one lurking around on 285/75's I think. Mine have worn 2mm over 30,000kms (set of 6). Not sure how the other lads KM2's are doing. I am also running a set of them in 245/75 on my Isuzu D-Max and have experienced great wear so far.

Size is a personal thing and I'm sure either one will perform the same despite the marginal difference in size.

Cheers
Keithy

[UK_P38]

Cheers Keithy,

This was my final decision to make after a lot of researching, thinking the 10mm extra width may be preferable. Will make the call on the day of purchase. I am trying to find a set of wheels to put them on too (keep my current as spares), preferably the land rover rims as I heard they have good beading and are a lot less likely to throw wheel at low pressure. I've found a set 16x7, do you know if these take them ok or do I need the 16x8?

Plan on getting the rims powdercoated, black car, maybe a gun metal grey? Important stuff ;)

[Keithy P38]

Yeah 16x7 will be fine for either of your choices. I have also stuck with factory alloys for the same reasons as yourself!

[UK_P38]

Picked up a set of 16x8's and going for the 255/70/16's, wheels in pretty good condition. Might not bother with getting them powdercoated, spend the money somewhere else more worthwhile..

[Keithy P38]

Good choice mate! I've been happy with mine so far!

[Pete38]

Yeh I'm running the km2's in 265/75/16 and no regrets so far, as mentioned in the thread I started a few months ago.

http://www.aulro.com/afvb/p38a-range-rover/157785-yeh-yeh-another-tyre-thread.html

[UK_P38]

Saw that link pbrown, clearly you have gone through the same thing. With your 265/75/16 do you know if they scrub when it's on the bump stops. I just don't want to be completely stuck in the event of complete EAS failure. I am running standard suspension at the moment, plans for the Gen 111's in the future when the $$ allows. I can cope with very minor scrubbing but as said don't want to become immobile or rip out liners!
Cheers guys, I know this has been thrashed out on many forums but good to get pecific KM2 info!

[Pete38]

Well they drive in a straight line fine and I think on full lock they are OK but I haven't been too tempted to try. But they do rub a little when half turning off memory. Probably still drivable, but I would be concerned doing damage for any proper driving.

But this is easily fixed cause I have packers to extend the bump stops in the field, well extend the bump stop plates actually. Never used them yet though.

But its a little more diff clearance that got me, and if in the odd chance something happens well I think I am prepared.

[Pete38]

And this is only a problem if you pop a bag.

EAS fault can be fixed using the emergency air kit. I have also added a switch on the dash to kill the EAS if a fault comes up and before it drops to the bump stops.

[Keithy P38]

Will be making up an emergency ecu off switch for mine in the near future! I popped a bag in hard low range bush territory, about 50km either way, a few river crossings and all on the bump stops! Not pleasant!

[UK_P38]

I'm going for the 265/75's, thanks for the advice pbrown!

Like the sound of the ECU switch but if you pop a bag then you're gonna loose all the air anyway? With the emergency kit can't you just shut off the blown bag and fill the others with a compressor to give you a bit of support to get out of a situation?

[Keithy P38]

If the ecu is awake it will send you to the bump stops regardless of how much air you feed in! Need to remove the delay timer if you want to pump it manually or shut the ecu off!

I managed to live without an eas fault when mine popped so after letting the compressors cool down a bit I could pump the other 3 bags up using the ecu and a jack on the offending corner to trick the system until I got to an obstacle when I had to shut the door properly. Which was not very long at all!

[Keithy P38]

You lads on 32's are making me jealous btw!

[Pete38]

It's not the size that matters its how you use it remember lol. But seriously these are the limit without more mods I feel. The front mud flaps had to be removed and now my car gets dirty ;-) And there are minor rubs which I find acceptable so They aren't perfect.

[Pete38]

Yeh the point of the switch is to stop it before it let's all the air out. And water crossings so there is less risk of a fault in water.

[UK_P38]

Appreciate the comments pbrown, i'm going to take the gamble and try to find the find any scrub points as I go. Given I gain confidence in the mechanical soundness of the car I will to start suspension mods in the future.

Had a search on here about that switch? Couldn't find anything. Have you just put a bypass in the door or similar?

Pick up the car tomorrow! :D

[Pete38]

I may not have read it in this forum. But the eas computer is under the passenger seat and there is a relay off memory which I put a switch inline to cut the Red and something striped wire that cuts the power. PM me if you have problems finding it when or if you put the switch in.

[mtb_gary]

Pbrown, do you get any error messages ie sped limited to 55 kph come up on the dash when you turn the power off to the relay? I've used the purple with a red stripe wire that connects to the relay as the power to control with an external switch.

[Pete38]

Pbrown, do you get any error messages ie sped limited to 55 kph come up on the dash when you turn the power off to the relay? I've used the purple with a red stripe wire that connects to the relay as the power to control with an external switch.

Yes I do. But it only beeps once and leaves the message on the screen so it doesn't bother me much. Then switch the eas back on even while moving and the message disappears. I guess this is the same as yours seeing you used the same wire (you reminded me which one it was when you posted it).

[mtb_gary]

I' m pleased it wasn't just me :D

[UK_P38]

So as not to leave the thread unaswered. I settled for 265/75/16 km2's. So far very pleased I did, not gone off yet but the tyres look good :D and don't appear to need a lot to stop srubbing. They rub slightly on the front inner liner (mubd guards are removed) and will rub no the top outer part of the liner on the rear (mud guards still attached). I plan to modify the liner slightly to keep full articulation and movement if the car goes to bump stops...

[Pete38]

Good to hear. I'm enjoying my 265/75/16 km2's as well and no regrets.

On mine the outer edge of the rear is damn close to touching when the suspension is let down but doesn't quite touch. Like can't put fingers in there. I can drive on access mode put it that way. But off road it is only the inner that touches as the axle/wheel wheel is normally angled when pushed up to the bump stops. It is very rare it touches so wouldn't even bother trimming myself. Even when the wheel has disappeared into the guard it doesn't often scrape so I don't think much articulation is lost when it actually does touch.

The front I have never had scrape off road, well no black marks in the guards. Only on access mode does it touch lightly when half turned I think. But yet again no guard trim for me as it's really rare.

So on access mode my car still rolls. But it I was on the bump stops I'd be putting the hard rubber packers I have on the axil plates where the bump stops touch. Got the trust worthy cable ties to secure them on there. Haven't done it yet but got the gear ready in case a bag pops and can't be bothered fitting the spare in the bush.

[DT-P38]

But if I was on the bump stops I'd be putting the hard rubber packers I have on the axil plates where the bump stops touch. Got the trust worthy cable ties to secure them on there. Haven't done it yet but got the gear ready in case a bag pops and can't be bothered fitting the spare in the bush.

Can you take and post up a photo of this bit of emergency kit please? I really like the simple sound of it as a lazy get out of jail card!

[UK_P38]

What offset are your wheels? mine are -57... I will take some photos next time a depressurise the EAS, not checked inner rubbing on articulation on the rear but was definitely sat on the outer part of the liner.. I reconthe front of my front inner liner is a little loose, that is all on the front...

Oh at the 55km limit comes one when the cable is plugged into the EAS ECU too...

[Pete38]

Can you take and post up a photo of this bit of emergency kit please? I really like the simple sound of it as a lazy get out of jail card!

I haven't yet done the install but will likely do it and take a photo on the weekend. Probably should check anyway in case I missed something that stops it working huh :-)

All I got was some hard ish rubber to pack the steel bump stop plates up higher on the axle and some good length cable ties to hold the square bits of rubber on the plates. Sorta like extended bump stops.

[Pete38]

What offset are your wheels? mine are -57... I will take some photos next time a depressurise the EAS, not checked inner rubbing on articulation on the rear but was definitely sat on the outer part of the liner.. I reconthe front of my front inner liner is a little loose, that is all on the front...

Oh at the 55km limit comes one when the cable is plugged into the EAS ECU too...


I'm running standard 16x7 p38 wheels so same offset.

To be honest mine might to at a full depressurised system. When only One bag popped I doubt because I tried letting one corner down completely when I first got the tyres.

Maybe I probably should have checked more thoroughly but I figured I had stuff to fix it at all times so I wasn't too concerned. And access mode doesn't scrub so normal days are ok.

Might be repeating myself but hey... But have definitely never scraped on the outer edge when off road and only once, maybe twice ever so slightly on the inside of the rear off road and I've done some rock climbs that I was quietly sh*@ing my pants with wheels in the guards and wheels off the ground... I actually expected to scrape more as the first test I did when trying to see if it would scrape squeaked and left a black mark on the inside of the rear. Maybe after 5000 km the 1mm wear has stopped them touching. Or that the slight air down for rock climbing helps...

[Pete38]

OK disclaimers first.

Not the most challenging bit of off roading but it is a little more than the video shows. Videos never do the heights and slopes justice... Cause those rocks were boulders lol.

But the rear right waa up in the guards a fair way at one point and the rear left up when the right was off the ground but you couldn't see that cause my car ain't see through.

Also I take no responsibility if you feel sick after all the camera shake.

Oh and excuse the few moments where the decent wasn't quite so smooth, especially the end where I thought the tow bar tube woulda scraped.

I'll sure to upload a video where it's more challenging and have less defensive comments ha ha.

Anyway after the long intro here it is....

https://www.youtube.com/watch?v=hN0Q0tbjb98&feature=youtube_gdata_player

[Pete38]

Double post

[Keithy P38]

They tuck up nicely!

[RoverHse]

My Rangie with 265/75/16 Wrangler MTR's fitted to the standard rims... they were great!

[DANMAL]

my rangie is running 265 75 16 km2's... doesnt rub at all when articulating, just rubs in front, in access height when turning (stock suspension), but i think my front guard liners are loose, missing screws or clips(whatever they are)..
265 75 16 km2s are the best thing i did to the rangie, UNSTOPPABLE with them on..
i drove up that bank n went back down because the "rambo" in his gu patrol and his 35's was convinced my car was a toorak tractor n my tyres were too small!!

[DT-P38]

Hey Danmal,

Where did you get your wheels painted? Was it a DIY or powder coat or what?

[DT-P38]

I haven't yet done the install but will likely do it and take a photo on the weekend. Probably should check anyway in case I missed something that stops it working huh :-)

All I got was some hard ish rubber to pack the steel bump stop plates up higher on the axle and some good length cable ties to hold the square bits of rubber on the plates. Sorta like extended bump stops.

Seen my popped a bag photo's? How ironic we were just chatting about all this last week!

[Pete38]

Hey Danmal,

Where did you get your wheels painted? Was it a DIY or powder coat or what?

I'm looking at using matt black plasti dip. It's a non permanent rubber spray paint designed for cars. But it's marked up a lot here as it's far cheaper in the US

[Pete38]

Seen my popped a bag photo's? How ironic we were just chatting about all this last week!

Yeh I did. You changed your bag in the field though huh? Made me add a small bottle jack to my kit. Did you jack between the axle and body? Impressive I say because while it was easy to do in the garage I've always feared doing one in the rough stuff.

[Keithy P38]

I believe it was I who did the bush bag swap, dt had a nice lump of lumber instead.

I used the bottle jack to lift the wheel off the ground, put a large flat rock under the chassis and once the wheel was off and the top clip off the bag, I lowered the jack. Reverse for re-installation.

Too easy

[DANMAL]

I'm looking at using matt black plasti dip. It's a non permanent rubber spray paint designed for cars. But it's marked up a lot here as it's far cheaper in the US

It's DIY, use VHT caliper paint, doesn't chip or carry on n the finish is good..
Just lightly rubbed it back, masked up Tyres n gave it 2 coats..
I was a bit sketchy on using pressure pack but the nozzle on the vht stuff sprays pretty even..
Cheers
Sam..

[p38oncoils]

Welcome to the forum mate!

A good thread to talk about! There have been multiple topics raised over tyre sizes on our beloved's! Each to their own with sizes though (search function is your friend)! We have a few P38's running KM2's here. Mine is one, on the 255/70's. another I'm aware of on 265/75's and Paul on 255/85's! May even be one lurking around on 285/75's I think. Mine have worn 2mm over 30,000kms (set of 6). Not sure how the other lads KM2's are doing. I am also running a set of them in 245/75 on my Isuzu D-Max and have experienced great wear so far.

Size is a personal thing and I'm sure either one will perform the same despite the marginal difference in size.

Cheers
Keithy

I'm running 285/75s and after initially modifying the front sill trim on the vehicle I have only minimum rubbing of the tyres under extreme articulation and only with the front wheels at certain angles. Below is a recent picture of it.

https://www.aulro.com/afvb/images/imported/2013/01/1247.jpg

[benji]

Have been following this thread with a lot of interest; itching for the ability of a KM2 etc, and I think the 265/75 looks more proportional.

RoverHSE how many km have you put on your Wranglers? I'm wondering how noisy they are, and how they stop in the wet.
I really want to go a mud tire, but have been told the KM2 when about half worn looses an appreciable amount of grip in the wet.
I've got 78,000km (60% worn) on my BFGATs and they still pull up like they were new.

Also wondering if anyone else has had experiences with worn mud tires.

[PaulP38a]

Benji... no, don't tell me that... I put 255/85R16 KM2's on my blue P38 less than a year ago and am loving them. It has done less than 15k KM in that time and they are still like new.
I also have the set of five 255/85R16 Maxxis Bighorns on other rims which are less than 50% and they were still handling and stopping well before I replaced them... much noisier and stiffer sidewalls than the KM2's though.

[benji]

Was talking talking to the owner of a local 4wd shop who told me that (very knowlegeable fellow); but it's just one opinion. Was just wondering if someone was driving on, say, almost worn out KM2s to verify it. Cannot be as bad as Kelly ATRs in the wet, a higher gip coefficient exists between baby poo and a wipe.

I've also been looking at the pro comps as well, which by all accounts are very good and quiet.

Just don't know.

Wet weather braking, noise and sidewall flexibility are my only concerns
If the KM2s brake as well at their AT's when half worn i'll be more than happy.

[glenhendry]

Ive gone 245/75-16 Wrangler Duratrac mud tyres. I love them. I didnt feel the need to go higher and these are 31.5" which improve over the 29" stock without rubbing. Mine still look very good after ~30kkm and are not noisy in the least. I havent noticed any reduction in grip, and I am very impressed about wet weather braking.

[highrr]

Can anyone tell me I was thinking of going 235 85 16s but I have not heard anyone mention these is this a good size or not?

[Pete38]

Similar diameter to 265/75 but narrower tread so imagine if anything they will likely scrape slightly LESS. But the tread of my km2's doesn't technically have a flat 265 on the road and some AT's might actually have flatter/wider tread touching the road and thus have the corners sticking out further... Yeh its not so clear but hope you understand what I mean.

[highrr]

Sorry mate, I don't really understand, are you saying it's better to run the
265 75 16 or the 235 85 16? given the width issues

[Pete38]

I would think the narrower tread will help with the clearance.

But my 265 KM2 only have just over 200mm in contact with the road and the remaining tread slopes off and doesn't appear to be the bit that touches. If the tyre had a more square shape and actually had 265mm in contact with the road then I'm sure they'd scrape much more.

My feeling is 235/85/16 is very unlikely to cause dramas, except maybe when eas failure occurs and no precautions are taken.
Keep in mind the axle and wheel "angle in" at the top when off road and pushing one side up into the guards. Quite different than eas failure when the body drops straight down.

265/75/16 most are ok but will scrape at some stage, perhaps some tread patterns will cause dramas though if they are tall and wide. Thing is not all 265/75/16 are the same height even, never alone the same tarmac contact path. I think the KM2 are almost what the calcs give.

[HEYVJ]

Ive gone 245/75-16 Wrangler Duratrac mud tyres. I love them. I didnt feel the need to go higher and these are 31.5" which improve over the 29" stock without rubbing. Mine still look very good after ~30kkm and are not noisy in the least. I havent noticed any reduction in grip, and I am very impressed about wet weather braking.

Glenhendry, size what rims were the 245's fitted onto? 7" or 8" wide?

Cheers,
HEYVJ

[redandy3575]

Don't know about you lot, but Silverstone AT 245/65-16's & MT 275/55 - 16's is my pick. These are fantastic tyres and swear by them, plus they're tough as nails. Silverstone is kinda the underrated quiet achiever in tyres. They don't spend huge in advertising, but boy do they make great tyres. Was considering Micky Thompsons, but after reading negative reviews and bad aftermarket service, I wouldn't even put them on my wheel barrow.

[Keithy P38]

245/65 is smaller than the factory size! Why would you decrease the diameter? Brings the diffs closer to rocks and ruts!

[seano87]

Ive gone 245/75-16 Wrangler Duratrac mud tyres. I love them. I didnt feel the need to go higher and these are 31.5" which improve over the 29" stock without rubbing. Mine still look very good after ~30kkm and are not noisy in the least. I havent noticed any reduction in grip, and I am very impressed about wet weather braking.

How did you work them out as 31.5"? I think you'll find it's a smidge under 30.5"?

[HEYVJ]

This is an online size convertor / calculator I have used in the past.
I hope this helps people.
Tire size calculator (http://www.miata.net/garage/tirecalc.html)

Cheers,
HEYVJ

[redandy3575]

245/65 is smaller than the factory size! Why would you decrease the diameter? Brings the diffs closer to rocks and ruts!

Sorry 245/70.....

Nah, actually sit higher than standard road tyres. Not too many AT's that are exact to factory size. Fits nicely under the wheel arch.

[Keithy P38]

That sounds better!

They would be a very close match to the factory size indeed!