Trailer tyre blowouts - twice on the same trip!

[Garth]

Appreciate some advice on what might be the problem, 18 year old BJ A - Max trailer - 4 wheels. Recent full service by trailer specialist (not BJT). Tyres 5 years old. Did not check pressures before setting off, but certainly not low - could have been too high? The trailer sits a little higher at the front given the height of the tow bar on the car? Was told this was not a problem by BJT and the trailer service chap!

My son Sam was towing the 7 up to Scotland yesterday and had two blowouts.. see pics below - just 7 with some luggage on the trailer, so not overloaded? Think car position on trailer ok, but did not measure weight at tow bar end? Tyres that went were both front tyres on either side of the trailer. 

First incident on M1 - drove slowly on 3 wheels to a tyre place who had a replacement - put existing spare on trailer and replacement kept as new spare. This blowout severely damaged the mudguard which had to be cut off! Is it legal to drive without a mudguard? See second pic below - cannot tell much from this - apart from what looks like delamination between the steel cords the tread?

Second incident happened a few hours later! This looks as though there is delamination between the steel cords and the tread?

Never heard of the tyre brand but says on the side manufactured by Deli Tire (not a typo!)

Thinking we may have just got unlucky with rubbish tyres? Ordering 5 new ones to be put on trailer for trip home.

Any insights most welcome! Thanks Garth

First blowout

 

Second blowout

 

[Jonathan Kay]

8 ply tyres seem to be recommended. Whatever they are.

https://www.lotus7.club/forum/speed/trailer-tyres-0

Jonathan

[ScottR400D]

Ply ratings are just a way of comparing load index to older standards. Originally the load capacity of cross and bias ply tyres was based on the number of actual plies there were in it. 

These days we have a load index as we probably all know and sometimes a 'ply rating' is added so that a comparison can be made with historical standards. 

I've only seen tyres fail like that through being too old or a combination of age, overload, underinflation and injury. I'm not surprised the fronts went first they seem to be carrying most of the load. I know the trailer tilts slightly to the rear but that won't matter when you're driving along, most of the weight's on the front.  

I wouldn't dwell too long on that but would get a full set of good quality tyres with ample load capacity as soon as you can. 

[Wrightpayne]

I was chatting to a guy who details caravans specialising in bringing painted ally and fibreglass panels back to new condition.

He said a lot of caravan tyres sit in one place for most of their life and invariably exposed to UV light. Owners often look at the tread depth thinking they are OK but the tyre has perished invisibly. The industry recommends to change them every 4 years.

[Garth]

Thanks for the comments will look at ones with higher load capacity - BJT say as long as the size is correct don't need to worry about the 'sort' of tyre! Still seems odd - the trailer was stored on blocks in a shed before I got it and the tyres are only 5 years old.

Not sure I understand why most of the weight is on the front - would it not be fairly equally shared, with the front and back tyres deforming slightly differently due to the relative position of the axles?

Will do some work on google!

[David_Long]

I think there is a belief that twin axle trailers are better than single axle. But they do stress the tyres more and the tyres tend to be a lower load capacity individually. Net result is that any uneven loading is a bigger problem and any tyre problems whilst towing are not so easy to spot.

 

But looking at your pictures, I would suggest overheating (for whatever reason) and motorway speeds was the problem.

[SM25T]

Unfortunately tyres and brakes are often neglected on trailers and caravans. They stand outdoors all year in all weathers and then expected to perform at motorway speeds.

[nutty7]

Under inflated tyres being one of the leading causes of tyre failure. When tyre pressure is low, its surface area that touches the road increases. The increased footprint will increase friction, which can cause overheating.

I own a Ifor Williams Transporta and the tyre pressures are 6.5 bar, 95 psi. I was suprised how high they were.

[Garth]

Thanks again for the comments - just had another call with BJT after struggling to get hold of the 140/70 R12 tyres they recommend - they have now confirmed that 155/70 R12's will fit, which I assume means 145/70's will also fit. Now to try and find some with high load capacities. Will make sure the tyre pressures are correct!

[OldAndrewE]

How about getting some 13" wheels to give you a better tyre choice

[Mcalvert]

Hi Garth - I had exactly the same thing a few years ago on my Minno when one tyre burst, then the other on the same side failed only 10 mins or so later.  I'm not sure what triggered the first wheel to blow (age?) but the problem is that when the first wheel blows, the trailer remains so stable that you don't realise it has until quite a while later, by which time the tyre is completely shredded and has thrown sharp bits of steel belt all over the place, damaging the other tyre in front or behind which fails soon thereafter.

The only good news is that I found you can get home fairly well (slowly and carefully) on just 3 wheels (probably not recommended practice however)

 

[7 wonders of the world]

Under inflation causes addition flexing of the carcass which increases temps and leads to delamination of the plys.

Take a look at Maxxis Trailermax tyres - and make sure yo have them balanced too !

Worth also popping a bathroom scale under the drawbar to check te nose weight , once you have it correct mark the trailer for location of the front wheels.

Also check the trailer drawbar height is set correctly for the tow vehicle, these can be adjusted with spacers between hitch and drawbar. - trailer should sit level

[Guy Lowe]

Tyres 5 years old

I change my trailer tyres every 3 years, very few of us have the same tyres on our tin tops for 5 years. 

[Garth]

Only tyres we could get hold of in Scotland from the tyre place in Fort William were 'Greenlander'. Spoke to a very helpful tech chap at Wheel Solutions who supply BJT tyres. He said that the 155/70 R12C is a 'commercial' Spec tyre with a load rating equating to 900kg and that with 4 wheels on the trailer even the cheaper brands would be fine!

Going to have to sort out the height of my tow bar - on two cars!

Other thing I have discovered is that the weight at the tow bar is dependent on the car rather than the trailer (obvious I guess!) - so need to adjust the Caterham position on the trailer for each car!

Have ordered a 'nose weight gauge' for the trailer - cheap at £35!

Thanks again all.

[Roger Ford]

After suffering a blowout on my Minno (which I didn't even notice until someone pointed it out in the paddock) I bought a set of four wheels and tyres for a tad over £200. From here: Towing and Trailers 

[grumpy the 7th]

Just a thought? is the auto braking snatching on on one side every time you back off the throttle?? 

Had a problem with one side locking up the wheel so that it smoked, got hot then released with the next throttle lift off causing the trailer to brake again.

 

[Rob Walker]

I have been towing my 7 for 20 years without any tyre problems until last year when I stated getting tyres failing as per your picture.  I have come to the conclusion that there are some sub standard tyres around now.  Mine were all made in China IIRC powerstar.   Even when correctly inflated or even over inflated they overheated at 60mph and delaminated.  Fit some quality tyres and I would go for 6 ply if possible and correctly inflate them and keep the speed down to 60 .

[Garth]

Thanks for the comments - the brakes seem to be behaving themselves, but will keep an eye on that - had a thorough service recently and was given a clean bill of health! I suspect my tyres were duff as you suggest Rob - see comments about inflation below.

My son replaced all the tyres in Scotland and has just driven back to London without any issues, although it poured with rain the whole journey so not likely to have been problems with overheating?

We checked the tyre pressures on the three remaining original tyres before replacing them and they were all over inflated which suggests the others which failed (probably but obviously not conclusively!) were unlikely to have be under inflated. I have come to the conclusion that the tyres were duff and were fine for the short journeys we have done to date, but did not fancy a long journey!

Also worth noting that the 140/70 R12 tyres that BJT recommend can be replaced with 155/70 R12's which are about 15mm wider and 21mm larger in diameter! There are many more tyres available in this size with more choice of load index etc.

Now to get a new mud guard!

 

[Guy Lowe]

Don't forget a cover for your spare   
 

) 

[andy_harries]

@garth

 

What pressure were you running? Reading this makes me think I need to check mine!

[Garth]

Where did that cover come from Guy?

I was advised to run my tyres at between 45 and 50 psi - chap I spoke to had a table of recommended pressures for tyres depending on the tyre size and trailer load. Suspect your trailer manufacturer would also be able to advise? Was told that broadly speaking over inflation will lead to premature tyre wear (centre of tyre) and the trailer being a bit 'bouncy', but unlikely to lead to tyre failure whereas under inflation more likely to lead to tyre failure as tread blocks move around more leading to overheating and then delamination?