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Discussion Starter #1 (Edited)
Following on from this thread:

http://www.hyundai-forums.com/cm-2007-2012-santa-fe/305897-santa-fe-need-replace-all-four-tires.html

That mentions that Hyundai (WRT to the Santa Fe) have a 20mm (about 3/4") tolerance in the rolling circumference of each tyre.

Is this a real number (I can find no source for that and the original other forum message has gone away), and would it apply to the Tucson's part time 4WD system?


I'm curious as, in the UK at least, 20mm is virtually the difference in rolling circumference between a brand new (8mm tread) and a legal min (1.6mm tread) tyre. Which would suggest you can switch tyres around and replace as you like without upsetting the 4WD system.
============

The only recommendation I can see in the owners book is: 7-52:

"It is best to replace all four tyres at the same time.
If that is not possible, or necessary, then replace the two front or two rear
tyres as a pair.
Replacing just one tyre can seriously affect your vehicle’s handling."


Sound advice and that's what I'd tend to do anyway - moreso on the front at least which takes the brunt of driving, steering and braking.

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Irregular tyre wear

I just got some accurate numbers back from the 1 year routine service and my tyres are, by position in mm:

Total Mileage from new: 8800 ish.

2.8 4.0
5.5 5.0

Front nearside has taken a hammering which is unexplained. Might be all the potholes and rough road edges we have in 3rd world Britain :wink:

I was wondering whether to put the spare in the F/N/S then do a front-back swap on all 4 which would give me:

5.5 5.0
8.0 4.0


but the Hyundai dealer advised against it on the vague notion of "too much difference upsetting something" (well, he said "windup" which isn't going to happen on a non locked system - so I'm not sure if there's any validity to his claim).

With all the dodgy info going around concerning matching tyre wear on 4WD systems, I'd thought I'd drop in here and see if anyone can add anything?

Cheers,

Tim

PS next year, I'll do some more frequent tyre rotation - I was going to this year, but the high rate of wear caught me out - they were pretty good last autumn when I least checked myself.
 

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A typical standard tyre is 701.04 mm diameter which gives 2202.31mm circumference. Tread wear from 8mm to 1.6 mm will reduce the tyre diameter by12.8 mm to 688.6 mm giving 2163.23 mm circumference - a difference of 39.08 mm.. It follows that the largest difference in tread depths is about 3 mm if 20 mm circumferential difference is not to be exceeded,

I have a Tucson 1.7 diesel manual now at 14000 miles with tread depths - lf 4.88 - rf 5.0 - lr 6.89 -rr 6.57

You need to get your steering geometry checked. And that rear tread wear seems a lot compared to mine and I tend to motor on when out and about!
 

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Discussion Starter #3
Well spotted - silly error, not doubling the wear!!! Thanks for spotting that.

That does make a bit more sense - and would go against putting the spare on with a 4mm tyre (although I still don't know where the 20mm figure comes from)

Yes - the wear is very high... These are the original Continentals (245/45R19). I do tend to floor it, but it's unclear why the rears are so worn... I maintain tyre pressures religiously. However, we have seemed to burn through tyres even on other cars, so I am wondering if it's our roads too.

The only thing that happened to the front was the F/O/S wheel took a hit that knocked the tracking out, but that was corrected within a couple of days - so the tracking *should* be spot on. It's weird...
 

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Discussion Starter #4 (Edited)
OK - going to email Hyundai UK about the 20mm thing - I'd hate to be throwing away part worn tyres without good reason...

Message sent. I asked (in the most concise way I could manage):

Hi,

Can you tell me please:

What is the maximum permitted difference in tyre tread wear:
1) Between tyres on the same axle;
2) Between front and rear tyres.

Reason for asking: I have seen a rumour on a forum that says 4WD Hyundais need the rolling circumference of each tyre to have no more than 20mm variation to any other tyre. This equates to about 3.1mm tread depth difference.

I'd would like you to confirm that number, or tell me the correct number, if there is such a specification?

Many thanks,

Tim

PS

The only thing the owner's handbook says is:

It is best to replace all four
tyres at the same time. If that
is not possible, or necessary,
then replace the two front or
two rear tyres as a pair.

I'd hate to be wasting tyres with 4mm of tread on, but equally, if having 4mm on the rear and 8mm on the front is going to damage the transmission, that would be worse.
 

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Discussion Starter #5
I've had replies from them reliably before after a few days, so hopefully we'll get to the bottom of this :)
 

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Discussion Starter #6
On an aside, I've seen other reviews on the ContiSportContact 5 wearing fast. Going to try the Uniroyal Rainsport 3 on the front next - good reviews for a summer tyre, cheaper and to my mind, a better tread pattern in the 5 minutes of snow we get in southern England.
 

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Edit: This link may explain
Well spotted - silly error, not doubling the wear!!! Thanks for spotting that.

That does make a bit more sense - and would go against putting the spare on with a 4mm tyre (although I still don't know where the 20mm figure comes from)

Yes - the wear is very high... These are the original Continentals (245/45R19). I do tend to floor it, but it's unclear why the rears are so worn... I maintain tyre pressures religiously. However, we have seemed to burn through tyres even on other cars, so I am wondering if it's our roads too.

The only thing that happened to the front was the F/O/S wheel took a hit that knocked the tracking out, but that was corrected within a couple of days - so the tracking *should* be spot on. It's weird...
Contis on a Hyundai? What next? My Tucson came on Hankooks as did my previous Hyundais albeit from different assembly plants ( i20 from India, i20 Gen2 from Turkey, i30 from Czech Rep and Terracans from S Korea). Must say I have no complaints about Hankooks.
Of course, on 19" wheels with a lower aspect ratio and stiffer wall you have to put up with the faster wear rate compared to 17" wheels ! :wink:

Edit: This link may explain http://tinyurl.com/yc49s585
 

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Discussion Starter #9
Right, got a definitive reply from Hyundai UK and they have very kindly given me permission to share the information.

It is from Hyundai UK's technical team (not dealer) and as such, you should consider it valid with respect to UK vehicles (my caveat). I'm sure your local Hyundai office would be happy to answer the question, in case there are any variations by locality.


The sent me an internal pamphlet which says:

"The maximum difference in tread depths between the front
and rear axle sets should be no greater than 3.5mm"

It reiterates the requirement to replace tyres as a pair on each axle.

It also says to put new tyres on the rear, BUT the email said that advice had been revised in the light of recent testing, and the current advice is to put new tyres on the rear.

That's basically it. At least something solid to work to...
 

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That's a little over 4/32nds in american terms. My tires are 11/32nds(8.75mm) brand new. So if the tires are less than 7/32nd(5.5mm) tread depth, then the difference is too great for the AWD system and all 4 tires should be replaced.
 

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Discussion Starter #11
I'm not quite sure what the tread is on the Uniroyals - it's getting marginal in my case. ContiSportContact 5 came in at 8mm (simple old fashioned depth tester).

It's getting likely that I might need to do all 4 - well 5, with the spare as I'd like to keep the same make. Expensive oversight - I had planned to do a full rotation including the spare, but over autumn they wore faster than expected and I was too busy to do a detailed depth check.

The book recommends a rotation at 7500 miles IIRC, but that's way off with these Contis - they wear too fast for that. I'll probably be looking at a 5 way rotation every 2000 miles or so...
 

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Discussion Starter #12
Question:

Rear drivetrain just has a regular dumb differential, doesn't it? Which means it will not mind a mm or 2 between nearside and offside...


I've just noticed my spare is part worn to centre 5.7mm (ish with a crappy old time gauge - I did rotate it in due to dinging a wheel and needing a repair).

Just noticed Hyundai gave me the centre depth on my tyres at the service the other week which probably relates better to rolling circumference:

4.0 5.2
5.9 5.6

I could swap rear to front and swap the low for the spare and get centre tread

5.9 5.2
5.7 5.6


which looks pretty reasonable. Then I get to wear them all down for the cost of a rotation (it's winter, I'm lazy, shoot me :)

OK - seems like a plan...
 

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On our cars, the prop shaft always spins, then there's a rear clutch inside the rear diff controls clamps in power from the prop shaft as needed. But from side to side, it should be an open diff I would assume.
 

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Discussion Starter #14
Thanks mate... When the weather's better, I'll look to doing more frequent tyre rotations myself at home. Seems to actually be a good idea on this machine.
 

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Discussion Starter #15
Just paid all of £20 British pounds to get a 5 way rotation at my favourite garage:

https://docs.google.com/spreadsheets/d/1qOFcojSjw4tjqXjzD0TDamtba0yRBful1vebrwKvjIs/edit?usp=sharing

That's pretty well balanced now. Should see me through to September (projected date) if wear remains constant then we'll replace all of them...

Bloke at the garage (who is a tyre specialist) reckoned the initial high wear on the nearside (left side) and on the inside of the tyre, was likely down to the British roundabouts (clockwise) and the state of the road gutter side.
 

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Just paid all of £20 British pounds to get a 5 way rotation at my favourite garage:

Bloke at the garage (who is a tyre specialist) reckoned the initial high wear on the nearside (left side) and on the inside of the tyre, was likely down to the British roundabouts (clockwise) and the state of the road gutter side.
The effect of cornering on roundabouts would wear the outside of the tread shoulder not the inside.
 
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