Posted: Wed Jun 13, 2012 6:18 pm Post subject: tyre load ratings and sizing
My Kuhmo KU36 tyres have scrubbed out on the insides in no time at all so I'm looking at getting a set of Federal 595 RSR but a little worried about the tyre load rating and also unsure of what size would be best.
Front rim = 9" & 36 offset
Rear rim = 10" & 36 offset
Looking at running 235/40 18 fronts. (91 load rating) would have liked wider but the load rating drops to low
But not sure what rear would be best
265/35 18 (93 load rating) sidewall height 92.71mm
285/30 18 (97 load rating) sidewall height 85.34 not much rubber
I'm sure the aristo should have 94 load rating or higher, problem is not many tyres come with this rating. Even the advan ad08 in those sizes don't meet it.
The Kuhmo were higher then the 94 load rating but they can't be rotated so that the inside of the tyre goes to the outside of the rim..
Anyone in the know ? Should those load ratings be ok? I'm towing a trailer frequently if that changes things also..
Joined: 22 Nov 2009 Posts: 2008 Location: BRISBANE, QLD
Posted: Wed Jun 13, 2012 8:25 pm Post subject:
Camber is only a wheel alignment away from being fixed guys. Id be aiming for something like .5 - 1 degree of camber. Remember when your suspention squats putting power down, your prob adding anouther deg of camber from the squat. 3 deg of camber while turning the tyres is going to chew out the inside edge. Also being that these are softer tyres than reg high performance street tyres you are obviously going to see more wear for less kms regardless of camber settings. _________________
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Every set of tyres I've had on the aristo even with stock ride height have chewed out on the insides.
The ku36's lasted I think around 7000klm. both front and rear are cactus.
I see that hankook RS3 come in a higher load rating, but they would need to be ordered from tire rack.
i be investing in some f&r upper adjustable control arms _________________
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I had the 285/30/18 Federal RSR's on my 11" rear rims. Put them on @ 122,000km's just got them changed @ 148,000km with the usual bad inside wear - still 20,000km+ on semi's was good value for a daily driver.
I had the 285/30/18 Federal RSR's on my 11" rear rims. Put them on @ 122,000km's just got them changed @ 148,000km with the usual bad inside wear - still 20,000km+ on semi's was good value for a daily driver.
Have just put on 285/30/18 Nangkang NS2's now.
Getting taxi mileage out of those and 285s arent a small tyre ! _________________
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Joined: 22 Apr 2007 Posts: 4010 Location: Perth, WA
Posted: Thu Jun 14, 2012 5:58 pm Post subject:
I'd be a little worried about 93 load ratings on the rear if you're towing a trailer. Would prefer more the 97 sorta level personally.
93 is 650kg per tyre, making it 1300kg on rear axle. Car weighs like 1.7t, which is fairly evenly distributed when sitting still but if you go and put your foot down you'll get probably 75% of that onto the rear and be approaching limit, plus the weight of trailer attachment..
Up at 99 load ratings, you're at 775kg == 1550kg on rear axle which is much nicer. You'd have to practically stand the car on the rear tyres alone for it to go over that.
If the wear is the inside half of the tyre it's more likely toe wear. Camber wear usually shows as an extreme inner edge degradation. (So Camber = inner Edge, Toe = inner Half) Either way, get it fixed and you won't have to change your tyres?
I've had 275/35/18 KU36's on the rear of mine for about 2years and they're still going strong. I'm lowered and all and not got any issues with abnormal wear patterns. I don't drive the car much, but it's probably over 10k kms.
There's no reason not to fix your alignment if it's costing you hundreds in tyre replacements... _________________
1994 Black JZS147 Aristo - RIP. Went swimming
New 1992 Aristo Project
Rusty, thanks for that info.
The car has had numerous wheel alignments and not one shop has said they couldn't acheive a road standard alignment. But still every tyre wears out about 1" of the very inner tyre.
Ok so the Federal are out then unless I go the 285/30 18 but federal 265 are already meant to be over size and closer to 275, not sure if the 285 will fit with my offset.
Looks like it will be Hankook ventus RS-3 as they come in higher load ratings but they will have to come from tire rack.
Joined: 22 Apr 2007 Posts: 4010 Location: Perth, WA
Posted: Thu Jun 14, 2012 7:27 pm Post subject:
I used to run 285's on I think 9 or 9.5" rims so they will fit OK.
If you're still having uneven wear I'd be going back to the alignment place and/or making sure you get printouts of the numbers from their system.
For reference:
Toe Wear:
Camber Wear:
THAT SAID:
If your toe is even a little bit out it will exaggerate camber wear.
So you may be getting Camber wear with -1 only because your toe is borderline. You should run maybe -0.5 to -1.5 camber. You can get up to -3 or so without excessive wear Only IF your toe is perfect. Toe on rear I think (correct me if I'm wrong) should be slightly toe-in but around like 0.1degree. 0.5degrees is too much. A Lot of shops just kinda wing it and say it's oK when it's not. And Toe-out is a 100% no-no on RWD cars.
The other thing you should check for is 'cupped' wear patterns:
which are almost exclusively due to worn suspension components.
So if your inner tyre wear is sorta cupped or scalloped in any way this could be the cause (nothing to do with alignment)
Hope that helps? _________________
1994 Black JZS147 Aristo - RIP. Went swimming
New 1992 Aristo Project
Joined: 22 Apr 2007 Posts: 4010 Location: Perth, WA
Posted: Fri Jun 15, 2012 11:51 am Post subject:
Yes for sure!
Worn suspension will cause it to move around a lot and give you weird wear patterns.
The other way you can try it out if your alignment place is willing is to attach the sensors, take an initial reading, go for a slow drive around the block and go back and take another reading. If any of the values are more than a little bit different its cause your suspension is moving around when you drive it and no amount of aligning will fix it. _________________
1994 Black JZS147 Aristo - RIP. Went swimming
New 1992 Aristo Project
Joined: 17 Feb 2008 Posts: 151 Location: Darwin NT
Posted: Fri Jun 15, 2012 12:44 pm Post subject:
So can anyone confirm what the wheel alignments settings for a lowered aristo with rims should be? I'm sure the alignment places up here have no idea and just wing it
I had the 285/30/18 Federal RSR's on my 11" rear rims. Put them on @ 122,000km's just got them changed @ 148,000km with the usual bad inside wear - still 20,000km+ on semi's was good value for a daily driver.
Have just put on 285/30/18 Nangkang NS2's now.
Getting taxi mileage out of those and 285s arent a small tyre !
Yeah but they were as bad as the camber wear photo in this thread! hahaha
But it also brings up the point to really have a good look at your tyres, I didn't even know they were that bad as I only had quick checks from the outside and never drive the car.
Rusty - Depending on wheel offset will determine scrubbing but my 245/45's scrub a little at full lock and my old 235/35's didn't - I only went a larger profile to get better front end clearance. Wish I went a 245/40 - probably would of been the best of both worlds for profile and no scrubbing!
Joined: 17 May 2009 Posts: 3928 Location: S.E Melbourne
Posted: Sat Jun 16, 2012 8:59 am Post subject:
285's on 10's +36 will scrub on the outer guards with proper camber and sensible ride height.
If proper handling and tyre wear are your main concerns forget about slamming your car without adj arms. Even with offset bushes you can't lower the car much without getting camber wear.
Id say 90% of aristos have shagged out bushes and balljoints. Making noises is the last sign of wear/damage and not what you should be looking out for. Have the car tested by a professional and replace the balljoints first then the inner arm bushes and so on then watch your car transform into a tight and predictable machine with consistent wheel aligment specs and suspension geometry.
So unless you have good bushes in there all you will be told be your local tyre shop doing the alignment will be "we adjusted it as far as it will go, see how that goes" = fail.
Joined: 17 May 2009 Posts: 3928 Location: S.E Melbourne
Posted: Sat Jun 16, 2012 10:32 am Post subject:
Factory tyre placard says. 93/94 for the front and 98 for the rears. Good luck finding low profile tyres with those ratings this side of $500 each.
The compliance sticker over the factory placard says 90/91. I run 235/40r17 90w rsr's on the front. Unless you carry 5 passengers each weighing 500kg at 270kph all the time, I wouldn't worry too much about it.
Most states stipulate tyre ratings must be equal or greater to factory spec, but seriously its not a commonwhore with 88H factory rated tyres.
EDIT: Missed the whole towing a trailer bit. Which I in NO Shape or form recommend. Calculate total weight you'll be carrying and use the site below to work out what rating tyres you need, taking into consideration the trailer will take most of the load its axles.
I'm not sure why you don't recomend towing a trailer.
I had the towbar made at a specialist shop and they have run bracing back under the car and also through the tyre well. They have said it is strong enough to tow what I need it for. But not to use it for big items like boats or caravans etc...
So looking at that site, I need 97 minimum to be safe. But the Hankook 285/35 rates at 101 which would be better. But that would need guard rolling you think?
The car is only slightly lower then standard.
hmmm either that or put smaller rims and go a proper tyre
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not much rubber
