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Tyres - blowouts, causes and how to avoid them?

BlackLightning998

Well Known and Active Website User
VOC Member
Evening All,

Three events this year cause me to ask a few questions about having a tyre blow out or lose pressure rapidly.

I had an incident this summer on my Rapide when the rear tyre lost pressure rapidly and caused the bike to become pretty uncontrollable at about 40 mph - the tyre rolling off either side of the rim and me snaking along the road on opposite lock like a speedway rider - and pretty frightening it was too. The culprit was some form of alloy stake that had been picked up from the road, gone into the tread and out the sidewall of the tyre - two puncture wounds.

Then Bill Bewley and his wife were spat off their Rapide in France, they subsequently found what they think was the cause - a rear valve pulled out.

Third, a friend of mine had a similar incident with the front wheel on his Rapide the other day and ended up in a hedge with broken ribs. He suspects the valve may have pulled out.

Now, I've had punctures on modern bikes in the past and never had such a frightening experience - I really thought I was going to throw the bike down the road.

I'm keen to hear of the sorts of precautions that VOC members take and what they have found, over the miles, work.

So far I have:

1 - Good quality tubes
Made sure I buy and fit a good quality tube.

2 - Right sized tubes and tyres
Tubes and tyres are the right size for the wheel.

3 - Rim tapes which are in good order
Fitted and in good repair, no spoke ends in sight.

4 - Good quality tyres
Made sure I buy and fit a good quality tyre from a reputable source - no old stock.

5 - Pressure set right
Run 22 front and 18-20 depending in the back.

6 - Nipped the locknuts
Nipped the two valve locknuts up on each other with a couple of threads showing through the rim to watch early if I am getting any tube/tyre creep that may pull the valve out.

7 - Got Tyre tread left
Make sure that I have a decent tread left and don't run the tyre to the end.

I haven't fitted security bolts and would be interested to hear the pro's and con's of this.

Any other thoughts and comments - not sure I'd like to contemplate this happening closer to 70 mph thank you very much?

Regards

Stuart
 

vin998

Well Known and Active Website User
VOC Member
VOC Forum Moderator
Stuart,
I had a rapid blowout of the rear tyre on my Rap 14 years ago. This occured at 70mph in the centre lane of the M5 heading for the Severn rally. The bike was 2 up (2 adults) and fully loaded with camping gear. I managed to get to the hard shoulder and down to 30mph before we came off. Also the weather was hot and sunny.

The tyre was a Dunlop TT100 and around 1500 miles and 6 months old. The tube was a good quality and new with the tyre. The eventual cause after much investigation was found to be due to running the tyre at 26psi which was too low!!!! but still higher than the old recomendations. This would allow the tube to rub on the flexing tyre and along with the weight on the tyre and the hot weather most probably caused the tube to overheat and fail.

Dunlop recommended to me for the weight of the bike and my weight etc to run on the REAR tyre at 30psi when solo and 36psi when 2 up and fully loaded with camping gear. I have followed these figures (for the rear) and have had no other problems.

What I do is to load up the bike, sit on it and look at the tyre deflection / distortion. What Dunlop suggested causes a slight deflection and this is what I aim for.

Tyre pressures on old bikes is a minefield as even the original style tyres which are made today are made from different (softer?) compounds to the 1950's therefore I suggest you do your own investigation and don't take the figures above as correct, but also don't take the 1950's Vincent figures as correct either as they would have been for tyres made in the 1950's.

Regards,
Simon.

P.S. The above works for me but as a disclaimer, do not take above as correct, but do your own investigation into tyre pressures.
 

Paul Ennis

Well Known and Active Website User
VOC Member
Punctures

For what it's worth, I use Ultraseal in my tubes. I hope I never have to find out if it works!
The demo at various events uses a tubeless tyre and punters are invited to drive nails into it. Of course it stays inflated. When asked about tubed tyres, they cannot guarantee that the tyre will not deflate, but they say if it does deflate, it will deflate slowly.
Cheers, Paul.
 

b'knighted

Well Known and Active Website User
VOC Member
Security bolts or tubeless tyres!

Many moons ago, on my first visit to the West Country at the start of a three week touring holiday, two up with panniers, top box, chin high tank bags and camping gear on the tops of panniers and top box, I had a scary incident on the B’knight. It was on an A road and, having followed a convoy of articulated lorries for miles, I blasted past the first of them and was in the gap between them when the rear tyre blew out. I managed to leave the road in a straight line as the road curved right.
To quote a friend “ That was when I discovered that adrenaline was brown”.
I happily concur with Simon’s analysis of low pressure causing the tube to rub on the tyre and along with excess weight on the tyre and hot weather causing the tube to overheat and fail.
I had always believed the major part of the problem to be the lack of security bolts allowing the wheel to turn inside the tyre and rip out the valve once the tyre had partially deflated, causing a sudden loss of all remaining air.
The bike was transported home and we restarted the holiday by car. When I got back home I started work on the cast aluminium wheel that now carries my rear tubeless tyre. It is great what you can hide under the cowlings. On one occasion I realised that my rear tyre was too soft and before inflating it, checked and found that the pressure was down to 8psi without causing any dangerous incidents. It is really sad that it is so easy to neglect things under the cowlings!
Even with the best maintenance a puncture may occur while riding. As the tyre deflates there is the risk of the wheel rotating in the tyre and ripping out the valve, however well secured, especially in the wet. I have had that happen on my Comet.
With a tubed tyre I really think that the security bolts are essential.
Would the factory have fitted them otherwise?
 

pifinch

Well Known and Active Website User
VOC Member
I remember in the seventies waiting at a set of lights next to a 750-4 ready to embarrass "The Worlds Fastest Bike", the lights went green, I dropped the clutch, the honda thingy flew away & We sat spinning the rim inside the brand new tyre - I forgot to tighten the security bolts! yes they are VERY vital on a tubed tyre.
steve
 

BlackLightning998

Well Known and Active Website User
VOC Member
I suppose the next logical question is.....

Thanks to all for pitching in - I guess one question that comes out straight away is has anyone ever had a problem like this with security bolts fitted?

Stuart
 

BlackLightning998

Well Known and Active Website User
VOC Member
Where do you get them from Paul?

Hi Paul,

Where do you get your "ultraseal" tubes from please?

Stuart

For what it's worth, I use Ultraseal in my tubes. I hope I never have to find out if it works!
The demo at various events uses a tubeless tyre and punters are invited to drive nails into it. Of course it stays inflated. When asked about tubed tyres, they cannot guarantee that the tyre will not deflate, but they say if it does deflate, it will deflate slowly.
Cheers, Paul.
 

timetraveller

Well Known and Active Website User
VOC Member
Could I ask for a point of clarrification? I absolutely agree about the need for security bolts with chromed steel rims but what about aluminium rims with serations all round both sides of the wheel. I have always assumed that security bolts were not needed if these were present and in fact used to sprint without security bolts if using this type of rim. However, what would happen if the tyre was punctured and running very soft I do not know and had not considered. Conversely I do recall getting only a mile or so down the road with a sidecar outfit without security bolts on a chromed steel rim before the tube ripped out of the rear tube. :)
 

Comet Rider

Well Known and Active Website User
VOC Member
Lubricant and other stuff

In the past I have used proper tyre soap when fitting tyres, but now I use talcum powder which seems just as good. My father has serated ally rims on his Comet outfit and he has never seen tyre creep.

Point to note, do what most sprinters and drag racers do, paint a small line acroos the side wall of the tyre onto the rim, this is an easy visual check that the tyre is not creaping.;)

Tyreseal, slime and other trade names do do a variant for TUBED tryres, we usually get ours from the BMF show or similar. We have is fitted to all our bikes, as well as the caravan. It does seem to help in maintaining a level tyre pressure.

Cheers
Neil
 

BlackLightning998

Well Known and Active Website User
VOC Member
Caravans

I've always found it difficult to maintain tyre pressure in the Caravan above 100 mph though........



In the past I have used proper tyre soap when fitting tyres, but now I use talcum powder which seems just as good. My father has serated ally rims on his Comet outfit and he has never seen tyre creep.

Point to note, do what most sprinters and drag racers do, paint a small line acroos the side wall of the tyre onto the rim, this is an easy visual check that the tyre is not creaping.;)

Tyreseal, slime and other trade names do do a variant for TUBED tryres, we usually get ours from the BMF show or similar. We have is fitted to all our bikes, as well as the caravan. It does seem to help in maintaining a level tyre pressure.

Cheers
Neil
 

Comet Rider

Well Known and Active Website User
VOC Member
I might of known

Hi Stuart,
Trust you:D
But I did have a friend when I was racing who was done by the plod for "agressive towing":confused:
He was caught doing 95 on the M6 in a Merc Sprinter fully laden with race bike and tools, towing a 4 berth twin axle caravan:rolleyes:

Cheers
Neil
 

Paul Ennis

Well Known and Active Website User
VOC Member
Ultraseal

No Stuart, they are not 'ultraseal' tubes: Ultraseal is a compound that you squirt in any inner tube or tyre. Motobins (BMW spares) stock it, but I expect they have a website. I'll have a look when I log off from here.
Cheeers, Paul.
 

vin998

Well Known and Active Website User
VOC Member
VOC Forum Moderator
Thanks to all for pitching in - I guess one question that comes out straight away is has anyone ever had a problem like this with security bolts fitted?

Stuart

Stuart,
The rear rapid puncture I described earlier occured with a security bolt in the wheel. Upon examining the wheel after, the tube's valve had not been ripped out and there was no evidence that the tyre and wheel rim had rotated in relation to each other. So yes I would always fit a security bolt.
Also when fitting a security bolt, don't forget the balance weights to eliminate the out of balance security bolt. I think the position of the balance weights and security bolt in relation to the tubes valve is mentioned in Know Thy Beast.

Simon.
 

BlackLightning998

Well Known and Active Website User
VOC Member
How does it work then?

Hi Paul,

Sorry for appearing thick - but tubed tyres are something I'm not that familiar with on a motorcycle, I guess then that you squirt this stuff inside the tubes with the valve core removed when you fit the tube do you, what does it then do, stay flexible running around the inside until there is a puncture, or does it coat the inside of the tube and form a flexible liquid rubber type membrane that is hard to pierce?

Is there a product website to go look at and find out about the science? Yes - here is what I found:

http://www.ultrasealnorth.co.uk/index.htm


Q - Can Ultraseal be used in tyres with tubes?

A - Yes!

Ultraseal will seal wounds in both tube and tubeless tyres as long as there is rubber recovery and it is not a dangerous wound.

A tube is not one of man's most ingenious inventions, and is very unreliable. The tube is basically made of rubber and synthetics. The wall thickness of a tube is not uniform and rubber content is very critical in terms of elasticity and rubber recovery. A tube that does not contain a sufficient amount of natural rubber cannot recover (close up) after sustaining a wound. It is critical that there be rubber recovery to assure a positive secure clot.

By installing Ultraseal into a tube, the problem of punctures can be reduced. The seal in a tube is not permanent. Tubes squirm inside a tyre at high speed if the puncturing object is left in the tyre and tube, it may rip the tube. Then even Ultraseal may not able to help. We recommend that nails be removed on a routine basis and the tyres air pressure be maintained at maximum PSI to reduce the squirming.

When a tube is punctured, the size of the wound in the tube may be much larger than the actual puncturing object; also tubes are very susceptible to ripping.


I'm trying not to be a wos, but I enjoy riding the Vincent "making progress" and these three events this year are causing me to think again about that, coming off the bike is not high on my "bucket list" I must say.

Having said that, I'd like to keep it close to original so fitting comstar alloys with tubless tyres isn't on my radar. I'd simply like to do what I can to swing the odds firmly in my favour for staying in the saddle.

I think I may just give Ultraseal a go, website looks good.


Stuart

No Stuart, they are not 'ultraseal' tubes: Ultraseal is a compound that you squirt in any inner tube or tyre. Motobins (BMW spares) stock it, but I expect they have a website. I'll have a look when I log off from here.
Cheeers, Paul.
 
Last edited:

hound

New Website User
Non-VOC Member
Tyres, Blowouts and Pressures

Stuart,
I had a rapid blowout of the rear tyre on my Rap 14 years ago. This occured at 70mph in the centre lane of the M5 heading for the Severn rally. The bike was 2 up (2 adults) and fully loaded with camping gear. I managed to get to the hard shoulder and down to 30mph before we came off. Also the weather was hot and sunny.

The tyre was a Dunlop TT100 and around 1500 miles and 6 months old. The tube was a good quality and new with the tyre. The eventual cause after much investigation was found to be due to running the tyre at 26psi which was too low!!!! but still higher than the old recomendations. This would allow the tube to rub on the flexing tyre and along with the weight on the tyre and the hot weather most probably caused the tube to overheat and fail.

Dunlop recommended to me for the weight of the bike and my weight etc to run on the REAR tyre at 30psi when solo and 36psi when 2 up and fully loaded with camping gear. I have followed these figures (for the rear) and have had no other problems.

What I do is to load up the bike, sit on it and look at the tyre deflection / distortion. What Dunlop suggested causes a slight deflection and this is what I aim for.

Tyre pressures on old bikes is a minefield as even the original style tyres which are made today are made from different (softer?) compounds to the 1950's therefore I suggest you do your own investigation and don't take the figures above as correct, but also don't take the 1950's Vincent figures as correct either as they would have been for tyres made in the 1950's.

Regards,
Simon.

P.S. The above works for me but as a disclaimer, do not take above as correct, but do your own investigation into tyre pressures.



I agree with Stuart that the modern produced tyres are a very different animal than the originals fitted to our 1950's classics. And yes I've found tyre pressures to be a minefield. I had a Front tyre 'snake bite' Puncture (2 small holes either side of the tube) whilst crossing the M4 flyover in August 2003, managing to control my Rapide to a halt at the traffic lights. The tyre was a Metzler and good quality tube, with 27lbs pressure. Last year after having new tyres fitted to my estate car, I checked the pressures whilst inflating for carring a holiday load and was amazed to find that my own pressure guage was out to the tune of 8lbs! So the actual Vincent front tyre was more like 19lbs! Some years ago I also checked my Trials BMW outfit tyres at 4 local garages and found they ALL differed, the worst being 5lbs adrift. I checked this against my local Tyre Specialist tyre guage. Finally, I have ALWAYS used security bolts on the Rear rim, whether Steel or Alloy on all the classic bikes I've had. I've had very few Rear punctures, in fact I can't remember having a Rear one on the Vincent, they were mostly on Trials bikes. I've been riding on and off for around 50 odd years and still learning!!!

Cheers ROD
 

Tnecniv Edipar

Well Known and Active Website User
Non-VOC Member
Could I ask for a point of clarrification? I absolutely agree about the need for security bolts with chromed steel rims but what about aluminium rims with serations all round both sides of the wheel. I have always assumed that security bolts were not needed if these were present and in fact used to sprint without security bolts if using this type of rim. However, what would happen if the tyre was punctured and running very soft I do not know and had not considered. Conversely I do recall getting only a mile or so down the road with a sidecar outfit without security bolts on a chromed steel rim before the tube ripped out of the rear tube. :)

See reply 3 above.
 

Tnecniv Edipar

Well Known and Active Website User
Non-VOC Member
I agree with Stuart that the modern produced tyres are a very different animal than the originals fitted to our 1950's classics. And yes I've found tyre pressures to be a minefield. I had a Front tyre 'snake bite' Puncture (2 small holes either side of the tube) whilst crossing the M4 flyover in August 2003, managing to control my Rapide to a halt at the traffic lights. The tyre was a Metzler and good quality tube, with 27lbs pressure. Last year after having new tyres fitted to my estate car, I checked the pressures whilst inflating for carring a holiday load and was amazed to find that my own pressure guage was out to the tune of 8lbs! So the actual Vincent front tyre was more like 19lbs! Some years ago I also checked my Trials BMW outfit tyres at 4 local garages and found they ALL differed, the worst being 5lbs adrift. I checked this against my local Tyre Specialist tyre guage. Finally, I have ALWAYS used security bolts on the Rear rim, whether Steel or Alloy on all the classic bikes I've had. I've had very few Rear punctures, in fact I can't remember having a Rear one on the Vincent, they were mostly on Trials bikes. I've been riding on and off for around 50 odd years and still learning!!!

Cheers ROD

Most tyre gauges are far from accurate , the types supplied with small hobby compressors are the worst in my experience. Unless the gauge is supplied with a calibration certificate I wouldn't trust it. The only exception that I have experience of is the small pocket gauge supplied by Michelin , I have one and it's within 1 psi compared with a calibrated digital racing gauge that I have. Forecourt pump guages are so inaccurate as to be a case for trade descriptions or whatever is appropriate. I also have a digital guage supplied by Snap On , the case is in the style of a conventional gauge but is digital , that is also accurate. I haven't tried the many commonly available digital gauges now available from Halfords etc , but I would expect these also to be more accurate than the cheapo analogue type.
 

Tnecniv Edipar

Well Known and Active Website User
Non-VOC Member
Regarding tubes in general , I would advise the following from my experience :-

Never use tubes from Taiwan , China or any other suspect area's , the best tubes available from my experience are Metzler , Continental or Barum. Go for the extra duty motocross tubes.

Exercise extreme care to avoid nipping or distressing the tube when fitting. Use tube powder so the tube slides easily inside the tyre when being inflated.

Never use oil based lubricant when fitting tyres , the rubber used in tyres and tubes is not oil resistant.

Maintain correct pressure , and if unsure of the correct pressure for any tyre , call the manufacturer , they have immense technical knowledge and will be able to correctly advise. Tyre suppliers and fitting depots know almost nothing in my experience.
 
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