Inner Tyre Wall Cracking - MOT Failure
Discussion
dhutch said:
A) how old are they tyres, they all have date codes on them.
B) what size are they, presumably low profile on an at, ms titanium diesal is bad enough!
C) can't believe how his hasn't been mentioned yet, but have you been straddling the square type speed bumps?
Daniel
On C yes although there aren't many around here. I have been driving into London recently and they're everywhere. B) what size are they, presumably low profile on an at, ms titanium diesal is bad enough!
C) can't believe how his hasn't been mentioned yet, but have you been straddling the square type speed bumps?
Daniel
Unless you're going over at speed (and it's obviously dependent on the severity of the cushion as well) then the loading on the tyre wall is going to be fairly minimal and far less, I would have thought, than going over a slight corrugation on a motorway at 70mph. I'd be very surprised if straddling them at moderate speeds has any effect on the tyre wall.
If you're hitting them at 20+ that may well be different, but then you'd be subjecting the tyre that's going over the cushion to much greater stresses as well.
If the asymmetry of the forces was a significant problem, we'd see a lot more tyres failing through cornering.
If you're hitting them at 20+ that may well be different, but then you'd be subjecting the tyre that's going over the cushion to much greater stresses as well.
If the asymmetry of the forces was a significant problem, we'd see a lot more tyres failing through cornering.
9xxNick said:
Unless you're going over at speed ...
If you're hitting them at 20+ that may well be different, but then you'd be subjecting the tyre that's going over the cushion to much greater stresses...
Given most are in 30 limits, I would expect it's is status normal to be going over at 20+ mph infact 35 is likely common. If you're hitting them at 20+ that may well be different, but then you'd be subjecting the tyre that's going over the cushion to much greater stresses...
If you watch while following a modern car over these humps, attempting to stradde them, often more than half the tyre width comes fully off the ground, focusing a huge force in the inner half of the tyre and inner sidewall. It's a reasonably well known failure mode for low profile tyres.
Daniel
I had a similar shock shortly after buying a Landcruiser several years ago, tyres still around 9mm (All Terrain) and looked great, until i was underneath doing some routine service work and noticed a black line all the way around one tyre just above the bead which proved to be a crack about 1mm wide but nearly down to the cords, inspecting the rest proved all were the same yet not a sign of cracking the outside or in the treads, tyres not old by any means and large 70% aspect to straddling road cushions wouldn't be the cause, i'd inspected the motor well i thought pre purchase but hadn't spotted this.
Did my offroader mate some good though, he ripped the cracking set up playing in the mud and rocks.
Isn't an emergency purchase both expensive and annoying, don't know why they do this, once you find out you've had you pants pulled down that's the last time they'll ever see you, if they looked after you (as the garage we use in the centre of our town does, nothing too much trouble) when you needed them you'll become a loyal customer and tell others about them, stupid short sighted business practice to take advantage in the heat of the moment.
Did my offroader mate some good though, he ripped the cracking set up playing in the mud and rocks.
Isn't an emergency purchase both expensive and annoying, don't know why they do this, once you find out you've had you pants pulled down that's the last time they'll ever see you, if they looked after you (as the garage we use in the centre of our town does, nothing too much trouble) when you needed them you'll become a loyal customer and tell others about them, stupid short sighted business practice to take advantage in the heat of the moment.
AlphaDelta said:
New fronts have now been fitted. Nexen tyres. I've no idea if these are any good but I wasn't going to drive away on what I had on there so went with it. At £90/tyre I'd hope they aren't complete s
te but I will replace them if they are.
They're average at best, and not worth anywhere near £90 apiece, but ah well, you've got them now, see how you get on.te but I will replace them if they are. AlphaDelta said:
A side issue was pitting on the rear discs. This was an advisory as there's still plenty of disc and pad left. I'm going to take them off and have a proper inspection at the weekend so any advice on this issue and at what point I should be looking to replace the discs would also be appreciated.
I took advantage of a nice bank holiday Saturday in the sun and fitted new rear discs & pads. The rear caliper slider pins were immobile and after some work and lubrication I got the pins out. There was alot of rust so the entire caliper was cleaned, re-greased and put back together with the new discs/pads. I suspect the state of the slider pins was part of why the pads were not making full contact with the disc. One to remember for next time. Smint said:
Isn't an emergency purchase both expensive and annoying, don't know why they do this, once you find out you've had you pants pulled down that's the last time they'll ever see you, if they looked after you (as the garage we use in the centre of our town does, nothing too much trouble) when you needed them you'll become a loyal customer and tell others about them, stupid short sighted business practice to take advantage in the heat of the moment.
It does drive me nuts. I won't be back to that dealership for a MOT/service again any time soon.My wife's Skoda Superb failed its MOT in July 2020 with severe cracking on the inside tyre walls of all four Bridgestone Potenza S001 (235/40 R19W) that were less that 3 years old having travelled 20k miles. We were told it was caused by driving on underinflated tyres. I disputed this as I checked the tyres regularly and always reset the tyre pressure monitoring, which would alert and continue to nah for under inflated tyres.
I replaced them with Bridgestone Potenzas as before. After suffering a blow out on the outer sidewall after hitting a pothole with a raised cats eye in the middle of it (May 2022 only 22 months old 15k miles). After removing the wheel I discovered the inner tyre wall was again cracked like before and split with the same type of cracks around the whole circumference of the tyre. They are diagonal cracks from left to right like spirals radiating outward.
I suspect that the causes could be
a. low profile tyres stressing the sidewalls driving over the rough roads of southern Hertfordshire
b. Rubber compound issue or manufacturing fault
c. driving over road humps and straddling "speed pillows"
I'm replacing them with Michelin Pilot Sport 4s
Warning to others to check the inside tyre walls, particularly if driving over speed humps regularly
I replaced them with Bridgestone Potenzas as before. After suffering a blow out on the outer sidewall after hitting a pothole with a raised cats eye in the middle of it (May 2022 only 22 months old 15k miles). After removing the wheel I discovered the inner tyre wall was again cracked like before and split with the same type of cracks around the whole circumference of the tyre. They are diagonal cracks from left to right like spirals radiating outward.
I suspect that the causes could be
a. low profile tyres stressing the sidewalls driving over the rough roads of southern Hertfordshire
b. Rubber compound issue or manufacturing fault
c. driving over road humps and straddling "speed pillows"
I'm replacing them with Michelin Pilot Sport 4s
Warning to others to check the inside tyre walls, particularly if driving over speed humps regularly
dec765 said:
My wife's Skoda Superb failed its MOT in July 2020 with severe cracking on the inside tyre walls of all four Bridgestone Potenza S001 (235/40 R19W) that were less that 3 years old having travelled 20k miles. We were told it was caused by driving on underinflated tyres. I disputed this as I checked the tyres regularly and always reset the tyre pressure monitoring, which would alert and continue to nah for under inflated tyres.
I replaced them with Bridgestone Potenzas as before. After suffering a blow out on the outer sidewall after hitting a pothole with a raised cats eye in the middle of it (May 2022 only 22 months old 15k miles). After removing the wheel I discovered the inner tyre wall was again cracked like before and split with the same type of cracks around the whole circumference of the tyre. They are diagonal cracks from left to right like spirals radiating outward.
I suspect that the causes could be
a. low profile tyres stressing the sidewalls driving over the rough roads of southern Hertfordshire
b. Rubber compound issue or manufacturing fault
c. driving over road humps and straddling "speed pillows"
I'm replacing them with Michelin Pilot Sport 4s
Warning to others to check the inside tyre walls, particularly if driving over speed humps regularly
The issue could be trying to straddle speed humps, that can stress both inner side of both tyres and wheel rims. It is probably best to take one wheel onto and over the centre of the speed hump.I replaced them with Bridgestone Potenzas as before. After suffering a blow out on the outer sidewall after hitting a pothole with a raised cats eye in the middle of it (May 2022 only 22 months old 15k miles). After removing the wheel I discovered the inner tyre wall was again cracked like before and split with the same type of cracks around the whole circumference of the tyre. They are diagonal cracks from left to right like spirals radiating outward.
I suspect that the causes could be
a. low profile tyres stressing the sidewalls driving over the rough roads of southern Hertfordshire
b. Rubber compound issue or manufacturing fault
c. driving over road humps and straddling "speed pillows"
I'm replacing them with Michelin Pilot Sport 4s
Warning to others to check the inside tyre walls, particularly if driving over speed humps regularly
This does sound like an age/speed hump agrivated issue.
I do wonder then, in tyre development, do manufacturers simulate different types of speed humps? Anyone in the industry know?
On your specific case OP; you mention mileage of the fronts, but not their age. Have you had those tyres from new or is the car new to you and tyres were already on? Could they have already done a stint on the rears?
Noting potential for MOTs to move to every 2 years; tyres certainly one to watch in-between, particularly if you live in a speed hump area.
I do wonder then, in tyre development, do manufacturers simulate different types of speed humps? Anyone in the industry know?
On your specific case OP; you mention mileage of the fronts, but not their age. Have you had those tyres from new or is the car new to you and tyres were already on? Could they have already done a stint on the rears?
Noting potential for MOTs to move to every 2 years; tyres certainly one to watch in-between, particularly if you live in a speed hump area.
Pretty much all tyres crack now...it isn't humps, the weather, climate change, Brexit, Putin's war.....none of those things.
Although it could perhaps be bullst EU regulations on rubber, tyres a couple of decades ago or more never suffered the same cracks when only a few months old. Some might still be ok 10-20 years old.
Although it could perhaps be bulls
t EU regulations on rubber, tyres a couple of decades ago or more never suffered the same cracks when only a few months old. Some might still be ok 10-20 years old.stevieturbo said:
Pretty much all tyres crack now...it isn't humps, the weather, climate change, Brexit, Putin's war.....none of those things.
Although it could perhaps be bullst EU regulations on rubber, tyres a couple of decades ago or more never suffered the same cracks when only a few months old. Some might still be ok 10-20 years old.
They used to have a decent sidewall though.Although it could perhaps be bulls
t EU regulations on rubber, tyres a couple of decades ago or more never suffered the same cracks when only a few months old. Some might still be ok 10-20 years old.Lack of aspect allowing tyres to flex properly, plus the obsession with flat roll free go kart type handling on everything including shopping cars, must have had an impact on the life of everything to do with suspension systems let alone the tyres.
My MB indy said probably 10 years ago that increasingly his work now comprised fixing suspensions, he put the blame squarely on speed humps and the pot holed third world standard surfaces that comprise so much of our road network.
I visit Park Royal industrial area regularly coming in from the Ace Cafe junction going in past the hospital, if you didn't have the seat belt on in a truck and opened the window a good chance you'd be ejected.
Have you watched the tyres of a car as they straddle a square speed bump.
Even something fairly 'mild' in todays eyes like 195x45 R16 the whole car is picked up on the inside 1/3 if the tyre with the sidewall on the inside crushed to almost nothing.
Physicals suggests that's not good for long life, I don't think you could design some that work well doing that ever.
As for 20 years ago. Tyres that shape didn't exist.
Even something fairly 'mild' in todays eyes like 195x45 R16 the whole car is picked up on the inside 1/3 if the tyre with the sidewall on the inside crushed to almost nothing.
Physicals suggests that's not good for long life, I don't think you could design some that work well doing that ever.
As for 20 years ago. Tyres that shape didn't exist.
InitialDave said:
dhutch said:
As for 20 years ago. Tyres that shape didn't exist.
I hate doing this to you, but you just did the old man "20 years ago, so, like 1980, yeah?" thing.20 years ago was 2002.
Enjoy yourself, it's later than you think.
But even in 2002 low profile tyres where I think less common and less low than we have the overall pool of cars today.
Yes you could buy a 330ci BMW sport with 255/35 staggered R18 back then, but a family hatch back with low profiles was still rare a feel?
Certainly in the 90s there where still a lot of cars running around on 80-65 profiles. 175/80 R13 , 185/75R13 , 185/65 R14 , 185/55/15 or 205/55R15 was the sports model.
dhutch said:
Valid to a point.
But even in 2002 low profile tyres where I think less common and less low than we have the overall pool of cars today.
Yes you could buy a 330ci BMW sport with 255/35 staggered R18 back then, but a family hatch back with low profiles was still rare a feel?
Certainly in the 90s there where still a lot of cars running around on 80-65 profiles. 175/80 R13 , 185/75R13 , 185/65 R14 , 185/55/15 or 205/55R15 was the sports model.
I'm afraid not. For example, the early-2000s Fiesta ST came on 205/40R17sBut even in 2002 low profile tyres where I think less common and less low than we have the overall pool of cars today.
Yes you could buy a 330ci BMW sport with 255/35 staggered R18 back then, but a family hatch back with low profiles was still rare a feel?
Certainly in the 90s there where still a lot of cars running around on 80-65 profiles. 175/80 R13 , 185/75R13 , 185/65 R14 , 185/55/15 or 205/55R15 was the sports model.
45 profile wasn't at all uncommon on "warm but not ridiculous" performance level cars of that period.
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