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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6308   
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I'll hopefully get a response from Continental tomorrow so I'll see what they say first.
but yes a great idea if I get nowhere with Conti. In fact a very nice chap on here has already offered to let me try a set.  |
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4th Aug 2013 3:19pm |
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| excossack Member Since: 22 Feb 2012 Location: North West Posts: 5861  
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When I first got me Defender I had 275/16 tyres and at 50-60 I had a wobble. Thought it was tracking - nope. Thought is balancing - nope.
Then I got some 235/16 ATs and the wobble went away. 1999 Defender TD5 110 Regards John M0VAZ Econet Station 48 no clock |
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4th Aug 2013 4:04pm |
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| WarPig Member Since: 04 Dec 2009 Location: Sheffield Posts: 1748 
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You probably just had a pebble stuck in the tyre tread  |
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4th Aug 2013 4:10pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6308
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please accept my apologies
having spoken to Continental it would appear I've shagged my tyres from drivin too slow and in a straight line - and thats for real. 
so my great fuel economy and fuel savings will have to go towards my new tyres. all I can say is try and avoid driving slowly on motorways.....(If I recall the actual quote was not slowly but constant speed in a straight line. - you live and learn - thats a new one on me. needless to say I'll be trying a different brand. anyone else come across this before? |
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5th Aug 2013 11:48am |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6308
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for those interested....
I have taken a look at the photographs you have sent me and although I cannot be 100% sure I think the most likely cause is a wear related condition known as 'Heel & Toe' or 'Sawtooth' wear. This manifests itself in an uneven wear pattern that can if it develops to its severest form can result in a noise similar to a worn wheel bearing and can cause a vibration. The cause is not as simple to explain because there is not a single factor. There are tyre, vehicle, pressure, driver, and environmental related conditions that are the fundamental reasons that the condition arises. I have attached a booklet on tyre damage that refers to this condition on page 8. If you have any question feel free to call me. Saw-tooth wear “Saw-tooth” wear is a wear pattern caused under normal usage with normal suspension settings. This is the outwardly visible (and audible) manifestation of various distortional forces at work on the tread. To explain this, it is better to first say something about ”tread design”. Tread grooves and sipes – a source of noise – are absolutely essential in ensuring safety on wet and flooded roads. In the case of low-profile tyres in particular, a higher percentage of tread void is necessary to take up the water and to improve the protection against aquaplaning. Cross-grooves for water drainage form “freestanding blocks” in the shoulder area. These shoulder blocks can wear to leave the “sawtooth” pattern as a result of rolling mechanisms under certain operating conditions. These operating conditions include: q Long, straight journeys at constant speed q Moderate driving style q Suspension geometry (alignment/camber).  |
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6th Aug 2013 9:28am |
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| tookaphotoof Member Since: 18 Mar 2013 Location: dordrecht Posts: 1279  
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So in order to get to my holiday destination I shoud:
a. keep the pedal down like a hooligan, b. avoid motorways and only take the twisty backroads. Thanks for the usefull information...  |
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6th Aug 2013 9:40am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17469 
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Interesting. What they (quite reasonably) call "saw -tooth wear" is essentially what I have always called "crenellation". Especially common on aggreesive or mud-type tyres, it is characterised by (a) the leading edges of tread blocks (ie the edge that hits the road first) wearing more than the trailing edge, resulting in a sloping surface up from the leading to trailing edges, and/or (b) alternate tread blocks wearing unevenly, so there will be a worn tread block followed by a less-worn one, followed by a worn one again.
First off this is an entirely normal phenomenon with tyres with sizeable tread blocks driven on hard surfaces. The softer the compound the more it tends to happen (so a KM2 is more prone to it than a KM1, for example), and the "harder" you drive the vehicle the more it tends to happen. Drive on the road on Muds as though you're running on road-biased tyres and it is more or less inevitable. It is actually caused, as far as I can determine, by the tread block 'scrunching' backwards from the leading edge as it comes into contact with the road. Since the front edge of the block is well supported it is quite solid when it bites. The trailing edge however scrunched back into the void between the tread block and the following block where is it not well supported and hence can deflect towards the centre of the tyre. The result is that the leading edge is loaded far more than the trailing edge and wears quicker, as well as generating the 'thumming' sound normal with mud tyres. Due to the uneven wear, the things you notice most as a driver are increased noise and a tendency for vibration, sometimes massive vibration, through the steering at certain speeds. The vibration is, of course, due the wear throwing the tyre out of balance. If the fron tyres are badly crenellated and if you get both front wheels out of balance and out of phase with each other and resonating, the steering disturbance can be very severe. The best solution to this is (1) to drive sensibly and not wear the tyres excessively in the first place and (2) periodically to swap the tyres from side to side and end to end. About every 6 months I swap the FNS and ROS, and the FOS and RNS wheels, so that the tyre rotation is reversed (to even up the crenellation) and the front and rear sets are swapped (to even out overall wear rates). There are those who will tell you nowadays that tyres shouldn't be swapped round in this way but usually they're people who seem to have a vested interest in selling you a new set. Incidentally the one complaint I have about the Kumho KL71, generally an excellent mud tyre, is the fact that you cannot reverse its rotation and even up the wear. It is also worth bearing in miond that an unevenly worn tyre wears unevenly faster, if that makes sense. In other words, once the unevenness gets to a certain point, it cannot be evened up. Michelin XCLs with their enormous tread blocks were very prone to this if driven hard on hard surfaces. Having said all that, your tyres really didn't look bad to me from your photo and I don't really see what the problem was! |
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6th Aug 2013 10:14am |
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| Natlas Member Since: 20 Mar 2013 Location: West Sussex Posts: 461 
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Hi Caterham and all.
I'm going to be very boring and pop in with a safety moment, a few messages ago a post referred to 36 bar among other things as a potential tyre pressure. This is confusing Bar with psi and they ain't the same. One Bar is 14.5 psi so 36 Bar would give a tyre pressure of over 500 psi which thankfully no compressor could ever reach but if you tried to pump your tyres that high you might just have an accident on the way! I doubt that anyone here would make such a mistake but I thought I'd mention it just the same. Good luck! John. 2.2 90 XS 88" Series One Old Norton 
Minerva |
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6th Aug 2013 12:02pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6308
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re psi and bar.....
it was only a joke which I thought I'd clarified. Blackwolf you appear to be spot on however Continental mention the 'saw tooth' effect can be brought on by moderate driving.
I therefore read that as aggressive driving would NOT cause the problem. All I can say is I've learnt something new AND I'm not very happy about it.
so no more bragging about good mpg from me cos I've learnt that equates to poor economy. 
AND had I not had all the other problems along the way I may have sussed this out before it became a problem......drat ! |
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6th Aug 2013 4:53pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17469
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It'd be interesting to have that conversation with them since I cannot see any engineering logic behind their assertion. Logic says the harder you accelerate, the more rapidly the wear pattern will develop. I think that they may have seen you coming (perhaps they lurk in this forum)!
I know from experience that if you drive hard, it happens quicker than if you pretend you're your granny - I have done this experiment!  |
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6th Aug 2013 6:24pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6308
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I feel that they saw me coming too - In fact I'm waiting to see myself on 'you've been framed'....
alas no. drive like miss daisy on continentals and you shag them - I have it in black and white.  |
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6th Aug 2013 6:30pm |
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| jst Member Since: 14 Jan 2008 Location: Taunton Posts: 8094  
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not the use you wanted to hear but i can understand it.
so whats next to buy tyre wise? or swap them around the vehicle? Cheers James 110 2012 XS Utility 130 2011 M57 bespoke Camper 90 2010 Hardtop 90 M57 1988 Hardtop |
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6th Aug 2013 6:32pm |
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| Happyoldgit Member Since: 14 Sep 2007 Location: Norfolk Posts: 3471 
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Swap them around, front to back and side to side, it's got to be worth a try surely?
Wait a minute, does the jack work? Steve.
Owned numerous Land Rover vehicles of all shapes and sizes over the decades. Current Defender: A non tarts hand-bagged Puma 110 XS USW. [Insert something impressive here such as extensive list of previous Land Rovers or examples of your prestigeous and expensive items, trinkets, houses, bikes, vehicles etc] http://forums.lr4x4.com I used to be Miserable ...but now I'm ecstatic. |
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6th Aug 2013 7:25pm |
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| Caterham Member Since: 06 Nov 2008 Location: Birmingham Posts: 6308
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'does the jack work'
never thought of that one - I'm scared to even try it know.
swapping them round - a job for the weekend. like you say its gotta be worth a try
been putting a few miles on the father in laws touran and thats been making a knocking noise at the back....had a wee look earlier and turns out the spring has 'popped' out at the top on the rear 
not doing so well with 4 wheel things ..... (its probably the bio diesel thats done it )
will keep you posted.... (probably the last thing you wanted to hear) |
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6th Aug 2013 8:20pm |
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