HighlandPete
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Posts posted by HighlandPete
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That's a great review mate, the more I read them the more I want it to snow now!!
How steep a hill did you try though cos if the main roads to work are closed I was going to try the country lanes but there is a very steep hill on the way?!!
I've had to use my car on a steep and S curved drive, 200 metres or so in length. A lead in off the main road, with a start from walking speed. 1 in 5 I'd gress, in the curved section. That tests all the working parameters, both going up and even worse, coming down. Nothing with summer tyres will touch it, if covered with snow, needs winter tyres, or AWD.
Plus I've used my car on other snow covered sloping sections with no speed to start with, and no issues with just moving off and doing what was needed.
Running normal roads through the Glen, absolute confidence and when out there on my own, with no other traffic, you can drive with total control at reasonable speeds, much faster than you'd dare even think off with the wrong tyres. It is other cars I worry about more, as they are the ones giving you issues.
HighlandPete
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will be interesting to hear each persons review of their chosen winter tyres once the snow comes
I run Vredestein Wintrac Xtreme on my BMW 330d, put them back on this week, as the temperatures have dropped.
Last winter they did everything thrown at them. I ran a few tests myself, (winter and summer wheel sets), on the same day, on our lane covered with solid ice and thin snow topping. Difference like night and day. Braking was most impressive. Also used it regularly, on thick fresh snow, ice, slush, up hills, forward and reverse up slopes. No issues with braking or car control, oh... and traction grip.
I had a car go out of control in front of me on black ice, and I had to brake mid corner, (worst case scenario for a winter tyre test) saved me ditching the car. Although I had a little bit of slip, was able to easily keep the car under control. Came back later to see another car had ditched on the same bend and had ended up in the tress. That could have been me.
Only slight negative, deep standing water to the verge edges is common up here, the Vred's tend to aquaplane more easily than my summer tyre set.
HighlandPete
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Wow, do you mind if I ask what you do/did as a profession? Not being rude, but you just seem to know about everything!
Back on topic, is that the same logic behind the theory that it is more economical to accelerate hard to your desired speed and then feather the throttle to maintain it, rather than very gradually accelerate to that same speed?
There is certainly good reason to accelerate quite briskly, using the engine where it is pulling strongly and working most efficiently, which gives the lowest BSFC, (Brake Specific Fuel Consumption), but we don't often get to see a fuel consumption map for our particular engine, to know exactly the best revs and loading to get best fuel consumption. It's a bit of trial and error, learning to get the economy 'sweet spot'. Also brisk acceleration in an appropriate gear, allows us to block change, (skip a gear or two) when up to cruising speed, which can also help economy.
HighlandPete
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One would think the only difference would be the tread pattern and silica mix, the actual construction under the rating ( H, V, X, Y ) and so on should be the same over the makes.
Strange as it may seem, the Michelin is the best many have used. I know from personal experience an 18" Michelin PS2 ZP, is the best working RFT I've driven on a 3-series car. Much more like a 'normal' tyre.
I do wonder if the run-on capacity is the same as the Bridgestone.
HighlandPete
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I published BMW's Q&A here> http://www.wheels-inmotion.co.uk/bmw-run-flat-problems.php
Remember reading it when you first posted it Tony, has to be BMW's stance.
I'm more thinking on the lines of this sort of comment.
http://www.tyresafe.org/news-and-events/de...standard-tyres/
There were others at the time and tyre shops have used those comments to refuse to fit non run-flats on customers cars with OEM run-flat fitment. Yes refused to fit non run-flats, other users have been asked to sign a waiver document.
HighlandPete
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It seems that most insurance companies have no issue at all. I've had dealings with a couple, including Direct Line, and they certainly want notification, as they do for fitting winter tyres, but appear more interested in the rims you use. In other words, are they OEM, or some 'aftermarket' modification?
What many have found, as long as you are using tyres to the BMW recommended load/speed rating, or above, there are no issues.
Fitting on the OEM rims is fine, as Tony has commented, even BMW have fitted non run-flats to satisfy customer complaints about RFTs. I discussed it with one dealer and he even checked with a customer, as to what tyres he was using on his 3-series, and his comments on the changes. The garage just reminded me to consider the options for an emergency, like space saver, mobility kit, etc.
The industry has published and distributed scare type documents about changing from RFTs, from what I understand. Many are nervous about fitting non run-flats since that exposure. Tony may have seen them, one is published by TyreSafe.
HighlandPete
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I thought the PAX system had bit the dust, after the class action in the States.
Business News
By failing to see the product through the lens of the customers' total experience, Michelin's hoped-for killer competitive advantage limped along until April, 2008, when the company announced that it would discontinue the line.From reports on the Class Action
A major tire manufacturer and car company have settled a nationwide class-action lawsuit brought by consumers who claimed they were misled about the benefits of their "run-flat" tires and were then further burdened by the slow and expensive repair process.In their 140-page consolidated amended complaint filed in May, the plaintiffs allege Michelin, which made the tires, and Honda, which outfitted certain cars and minivans with Michelin's PAX Tire and Wheel Assembly System, failed to disclose that the tires last half as long as radial tires. They also alleged the tires are "prohibitively expensive to repair and replace" and that sufficient repair facilities and stock of the tires and other parts of the PAX system do not exist in the U.S.According to the suit, the paucity of repair facilities, exacerbated by the system's discontinuation, has led to inconvenience and poses a safety risk for those who must drive on bad tires.HighlandPete
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I'll go with stress fatigue, can be high duty cyclic loadings, even without any stress raiser. Could be some age hardening depending on the material.
The experience with BMW wheels with RFTs, show rims can crack like that, sometimes several places around the rim, (seen seven cracks on one inner edge) so suggesting loadings are far too high for the expected life cycle.
HighlandPete
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or more importantly BMW choosing to use run flats should have made considerations in the geometry
In many countries run-flats will be mandatory, so BMW are compiling, but seemingly they are not making geometric considerations..... we are.
Don't forget BMW suspension is designed for run-flats.....
often quoted by BMW. Nah, they can't be wrong. :lmaosmiley: I've seen pictures like above, where the tyre has seperated. Get the warning 'bong' and 5 miles further on, total tyre failure. So looks like the X5 had a very close call before failure. Also seen pics where it looks the same as above, but with a flat and the owner was praising the run-flat as it 'probably saved his life'.
Don't think everyone using the run-flat is getting, that without very close inspection, run-flats are contributing to premature tyre failure.
HighlandPete
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Yeah that was it.......maybe warped means run out in the trade?
I'm sure localised contamination, corrosion, run-out, are all bagged together as 'warped' to many.
A badly mounted disc with resulting run-out, can be forced to 'sort of warp', during braking, to try and run true. So after removing, if measured for run-out it, can actually read as 'warped'.
HighlandPete
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I totally agree....
The warning threshold is to vast, i feel this is because the warning is intended for a flat tyre rather than a tyre that needs maintenance. Owners are either misinformed or ignorant to what the system promises.
+1
The indirect system is really a very poor system when we think about it. Many users won't have any idea. I also fear that there will be even less checking of pressures than at present.
HighlandPete
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This Merc today, i made a visual observation of the rear body trim height being a little low, the tow bar and the complaint since the rear camber on this Merc is not adjustable. The tyre wear is camber so the "WHY" mental button get hit.
If only more folks would ask 'why' when the obvious doesn't fit the problem, then the motoring industry would have a few more friends.
Good to hear when success is achieved by a bit of 'out of the box' thinking.
WIM 1, Merc Nil.
HighlandPete
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Are they spy shots of a tyre maker, testing the latest run-flats?
A real alternative to the Brickstones....
HighlandPete
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If you had bought a stag back in the mid 70s the state of the engine bay wires would have been the least of your worries.....
So true... Worked in a Triumph/Rover garage at the time and heard it all... "I think I've cooked the engine", "and I bled it properly", "was only a small water leak".
HighlandPete
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At the Lecturer level i charge nothing because i'm keen to educate this sorry area, reads odd in a business sense but that's how i feel.
Tony, so refreshing to see and read such a statement. If only more businessmen could see beyond the immediate cash benefits of any decision. I believe you should 'wobble your head' as much as you like.
HighlandPete
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There also comes a point where we need to sit back and think about the power and performance our cars flawlessly deliver a think all this performance and energy goes through the tyres, can we really, honestly expect a perfect world while driving the perfect car...... When it come to a long well known bend and we "floor it" we don't get out at the end of the journey an check the tyres and yet they hold a historical image of events we try to explain today.
Ain't it the truth... was down at the dealer a couple of weeks ago and a nearly new 3-series was sat outside the entrance with front wheels turned. The outside shoulders on the front tyres were absolutely hammered. One of the worst I've ever seen on a car, but plenty of tread (6 - 7mm) in the middle. Bet he's the sort of driver who 'loves' the sharp turn in on the big rims.
HighlandPete
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Martin
Your pictures do appear to show more wear on the inside, whether the type of driving, or needing an adjustment, only a check will show.
I know from the wear pattern and tread depths across the tyres, I'd personally be running a couple more psi than your original figures, to try and balance out the wear rates.
On the bigger issue of getting high mileage out of our current tyre designs and specs, even for motorway use, we do seem to be all over the place with what users get. I'm sure Tony is seeing this all the time, and some unusual wear, even when the geometry is inside manufacturers tolerances.
HighlandPete
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Interesting point regarding temperature and actual pressures, another reason to increase from the minimum setting I guess. I have tried in the past to inflate my tyres with Nitrogen (Uniflate) but to be honest I didn't notice any difference in neither wear of nor driving.
When I examined my tyres with the wheels off the car today (I checked the rears while I was at it also which are wearing fine, but they have not done too many miles yet) I did notice that whilst the 'Saw-Tooth' effect is indeed apparaent on both inside and outside shoulders of both front tyres, it is actually slightly worse on the inside edges of both fronts. They are wearing evenly in comparison to each side i.e. both sides are mirrored perfectly from left to right. The leading edge of the outter tread blocks are more prounced, but the inner edges are more wavy if that makes sense - sort of a more clear highspot and lowspot. Swapping from side to side has certainly began to reduce the level of 'Saw-Toothing' (I have done about 1500 miles since swapping).
Looks like I'll have to get a pair of fronts ASAP and hope the increased pressure avoids this happening in the future! If this is the cause, it will have been a costly mistake.
Martin
A personal viewpoint, but I'm sure quite a few will have been caught by excessive, or odd tyre wear, due to the colder than average winter period. Some will be due to tyres running lower working pressures, due to not warming up the same.
Are you planning to visit WIM, to have the geometry checked? As you mention the inside wear is different, may be wise before fitting new tyres. Have you any pictures of the wear pattern to post on the thread?
HighlandPete
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Thanks again for your valued comments! I guess my comments about wearing the centres of the tyres was really as a knee-jerk reaction to the rate at which the rears wear in the centres - a typical characteristic of tyres this size I'm told. Anyway, your comments regarding pressures on the front is understood and I will bare this in mind.
This may then have been caused by pressures being too low - but I guess the damage is now done. So, apart from slowing further damage down be switching tyres side to side as I have done and by increasing the pressures as I have done there is nothing else I can do to reduce noise until I replace the tyres...... afraid it will have to be a 'turn the radio up' approach in the short term as long as they are safe (but noisy) which they appear to be!
Martin
Noise generated from tyres on the latest BMWs is not unusual, some tyres have had many complaints and even Technical Information Bulletins (TSB) on the issues. Not a simple issue or easy solution.
As to the rear middle wear, (I'm sure Tony will add his comments), but it is not all about overinflation. Centrifugal growth at high speed and high tractive forces, particularly on high powered RWD cars can cause far more middle wear on rear tyres, than a couple of increased psi. You can still get rear middle wear on high powered RWD cars at low setting pressures.
Which brings me to another variable we sometimes miss. When using the lower pressure values, (which makes things worse) we sometimes never achieve the hot working pressures we really ought to be running. Cold/wet weather can accelerate tyre issues, often we do not consider the pressure setting may not be high enough for our use. Easy to be running 3 - 5 psi lower than we think, just because our tyres don't get hot during some conditions of use. We do need to compensate, particularly on low profile tyres, as the wear rate/pattern is far more critical than running 'loads of rubber', from my experience.
HighlandPete
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At least we have true 'like for like' tyres. Eliminates one issue.
You mention the 'saw tooth' on both shoulders, you mean of the same tyre? If so, are the saw tooth forms in the same direction? Meaning the leading edge is towards the front on either shoulder, (hand across them at the top of the wheel). Gives a clue the geometry is not far off ideal settingas, if at all needing adjustment.
I still believe a part of this wear is accelerated by running pressures at the low side of BMW's recommended rating. As said before, many users find the tyres need more pressure to work better and also balance the wear patterns. It is hard to wear the middles of front tyres on BMWs, without using excessive pressures. You'd notice the compromised drive chartacteristics, before you ever had too much pressure, if you increase and try at small incremental increases.
You mention the weight... it is all relative, light weight materials don't mean the car is light, still a 'weighty' car in real terms. The use of aluminium has really just stopped our cars getting too bloated in weight.
I swapped my original Bridgestone tyres 'side to side' to balance the heel and toe wear, which it obviously did, but the tyres were never as quiet afterwards. Stopped them getting worse and higher pressures slowed down the shoulder wear, but still came off at 15k miles with loads of middle tread, but useless as tyres.
HighlandPete
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What has me baffled is why the first pair of front tyres didn't do this? These were the exact same make & type. What tyres would you recommend as alternatives?
Just a thought, are the replacements OEM as in BMW 'star' rated/marked tyres, or the standard Continental offering of the same type and size? That can make a big difference on tyre wear and performance.
HighlandPete
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Completely standard 320d Coupe Convertible. 58 plate with approx 20k on the clock.
The two pictures were of each front Tyre. The tyre with the least wear is how the rears are going too... so that's 4 corners he will need replacing pretty sharpish. The wear pattern just seemed completely strange to me. At first he checked the bad wheel and thought some trim must have been rubbing against the inner wall, but after getting under the car i couldn't see anything and checked out the other tires. All 4 are going the same way.
What pressures do you run on those front tyres? Checked regularly? Do you make lots of short runs, less than 12 - 15 miles?
I hope you haven't been relying on the TPWS* for warning of a low pressure, as it can take a significant drop in one tyre to trigger. The big problem with the indirect ABS wheel sensor based system we have in the UK, if all tyres drop over time we can run on far too low a set of pressures, without any warning. It requires quite a rapid air loss, on the run, to get the warning trigger. Or something like an overnight slow pucture to get the warning 'bong'.
* BMW don't normally use the TPMS (Tyre Pressure Monitoring System) reference anymore, as it is not strictly a monitoring system. But use acronyms such as TPWS (Tyre Puncture/Pressure Warning System), latest is, Tyre Defect Indicator (TDI).
There's been a false sense of security, which has lead many to feel they don't need to check tyre pressures, they'll be told when to.
HighlandPete
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Interesting thread...
This problem does seem to be very common on BMW suspension setups, even from new. One thing I've noted on three different tyre makes (on one car) that they all have the tendancy to 'heel and toe'.
One thing I've kept a close eye on is, inside vs. outside, tendancy to 'heel and toe'. Obviously asymmetric treads will be slightly biased to one side, but directional tyres of symmetrical tread patterns will wear very similar either side of the front tyres. That teaches me the tyre, along with use, is more the culprit, rather than the geometry.
I know a lot of BMW users run the low pressures on front tyres, to try and help comfort, and stop some of the steering/tramlining issues, but to me that is a asking for tyre wear issues. Comfort and more control comes with smaller rims and more rubber, not ultra low profiles and compromised pressures. Best performance, even unloaded often requires about +0.2 bar (3 psi), than the low placard recommendation, on front tyres of many BMWs.
I'm not at all surprised at the side wind issue and low tyre pressures contributing to it. To me 30 psi on 19" front tyres seems so low anyway, with a 6-pot diesel sitting above them, whether it is a 3 or 5-series. I run 2.4 bar (35 psi) on the front of my E91 330d touring for normal use, and that is on 17" tyres.
HighlandPete
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Yes, they are allowing the tyre to deform so it can adopt the camber positions..... It's a pants solution because the tyres "slip angle" or lets say roll is greatly increased giving the feeling the rear is on ice.
As an engineer I sense tyres are getting far too hi-tech. Too much expected from one component in a suspension system. The problem as I see it, as the technology gets even more complex, more compromises can come back and bite the users and manufacturers. Wait until the Bridgestone G3's come into the market, rubber with heat reactions seems a step too far, IMO. Perhaps the reason we are waiting longer than anticipated, from the big PR exercise, before product is ready.
HighlandPete
Summer and Winter Tyres on the same rim?
in Tyres / Wheels
Posted
I'm in an auto, true, it is a pretty advanced box by comparison to many older ones, but honestly, an auto it is not an issue.
As said, 2nd gear starts are the typical auto snow/poor surface programme. Drive gently, use the throttle lightly. No need to copy the folks we see (manual or auto), spinning at 1,000's of revs and getting no where.
I will typically use the full auto 'drive' mode in good quality snow, but when there is poor snow/ice conditions, will go over to manual mode and particularly so for engine braking, to benefit from the car retarding from the rear and keeping maximum stability.
HighlandPete