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Tyres - blowouts, causes and how to avoid them?

bmetcalf

Well Known and Active Website User
VOC Member
Security Bolts

You guys are making me paranoid. I have been riding my Rap since 1980 with no security bolts on my rear steel rim with no problems. How long will that last?

Actually, one time I had a medium leak in the rear tube, while I had a very stiff sidewall Michelin tyre on and rode to a gas station at up to 30 mph, aired it up, then rode to a friend's garage to store it until I came back with a fresh tube. It was a bit squirmy and I didn't try any high speed cornering. I told the story to Dave Matson and he said the speed flings the tyre outwards and shouldn't be too bad in a pinch. His ideas of speed are different from mine, though.
 

John Cone

Well Known and Active Website User
VOC Member
Having read this thread from start to finish it accures to me that most people are running their tyres too soft. I have in a past life been a tyre fitter and fitted a lot of tyres to bikes. The use of proper tyre lubricant does not creat tyre creep as it dries out after a short while. On my Prince before it went into hibernation I ran it on Metzlers back and front with the pressures 28 front & 36 in the rear because you never know if and when you will need to go two up. Having Dunlop alloy rims I still use tubes with security bolts "whether you can still buy them I don't know". After having the bike off the road for the last 11 yrs i decided to check the tyre pressures, the front had only lost 5 psi the rear was down to 10 psi not bad me thinks!
 

Comet Rider

Well Known and Active Website User
VOC Member
Modern tyre security bolts

Buyer beware!

Most modern tyre security bolts are designed for modern rims that have a deep well in the centre (such as motocross rims) and are unsuitable for our shallow well steel rims. The new style security bolts tend to trap the tube between the bolt and the sidewall of the tyre..

Neil

PS
don't ask how I found this out, it's painful:eek:
 

BlackLightning998

Well Known and Active Website User
VOC Member
Unfortunately similar pain....

I had a similar embarrasing experience, I changed the tyre the night before going to the Riders Rally in York - put a new tube in whilst I was at it. I left the bike on the ramp and was chuffed with myself to be going to bed early around 10pm for a very early start the next morning - I thought, I'll just take it off the ramp, turn it around and be all ready for the off in the morning. Well you've guessed it, as I took it off the ramp I felt it heavy on the rear tyre - it was flat - I had nipped the tube as I put it in and fitted the tyre. So much for an early night, out with the wheel, off with the tyre and fit a second new tube (thank goodness I had one) - finally hit bed after 11pm.....

It happens.


Stuart
Buyer beware!

Most modern tyre security bolts are designed for modern rims that have a deep well in the centre (such as motocross rims) and are unsuitable for our shallow well steel rims. The new style security bolts tend to trap the tube between the bolt and the sidewall of the tyre..

Neil

PS
don't ask how I found this out, it's painful:eek:
 

Tony Cording

Well Known and Active Website User
VOC Member
Tires and blowouts

Not much mention has been made of the ubiquitous valve stem. There were a couple of comments about the valve stems pulling out due to tire creep, which begs the question about what was done with the valve stem nut. The majority of us over here place the nut against the valve stem cap, not against the rim, to allow for some flexibilty in the event of minor creep. We haven't had any stems pull out, something to think about.

Tony Cording

p.s. Seen on a restaurant menue cover:

"He was a wise man who invented beer - Plato".
 

donrapide

Website User
Non-VOC Member
Re: What size, is it for a solo? I've been using a 21" WM1 rim with originally Avon Speedmaster 21x3.00 tyres, which still seem to be available.

Not being keen on the milage from these I'm currently running a Pirelli 80x90x21 which seems to be a very good tyre. My tyre supplier, ex Speedway and now Sand Racer, tells me it is a Harley fitement so it has excellent speed and load ratings.

On my post war twin I have used, first 20", then 21" and finally 19" with a 3.60 section. (Due to availability over the years) The best for handling was the 21", then 20" and the very worst was the 19"x3.60. The 19" spoilt the steering and the handling.
 

wld50

Well Known and Active Website User
Non-VOC Member
standard front wheel

Re: What size, is it for a solo? I've been using a 21" WM1 rim with originally Avon Speedmaster 21x3.00 tyres, which still seem to be available.

Not being keen on the milage from these I'm currently running a Pirelli 80x90x21 which seems to be a very good tyre. My tyre supplier, ex Speedway and now Sand Racer, tells me it is a Harley fitement so it has excellent speed and load ratings.

On my post war twin I have used, first 20", then 21" and finally 19" with a 3.60 section. (Due to availability over the years) The best for handling was the 21", then 20" and the very worst was the 19"x3.60. The 19" spoilt the steering and the handling.
For what I believe is the original for a standard Comet, WM1 3.00 x 20

I haven't managed to find a 20" inner tube, does anybody have any sources or ideas?
Should I use a 19" inner tube, or a 21" inner tube instead?

lyn
 
Last edited:

wld50

Well Known and Active Website User
Non-VOC Member
Central Wheel Components

Dear Nkt267
When I initially found problems in obtaining a 20" inner tube locally for our 20" front wheel, I then contacted Central Wheel Components. They said that 20" tubes were no longer available and they now supplied a 'small' 21" tube.

Watling Tyres and a friendly local bike shop confirmed this unavailability, but both suggested using a 19" tube, the former said I wouldn't get a 21" tube in.

At this point with the jury 2:1 in favour of 19", I posted the query on the forum.

I've had one private reply to my posting who said he used a 21" tube, so we have 2 all.

Are there any more opinions out there?

lyn
 

donrapide

Website User
Non-VOC Member
I've had a conversation with my tyre supplier, Steve Lomas of "5-1", he is the ex speedway and now sandracer I have already mentioned.

He confirms that the 20" has not been available for some years now, what he has done several times, with complete success, is to fit a 2.50/2.75 x 21" tube. When very slightly inflated the diameter is the same as the inside diameter of the 20" tyre. The extra length can be accomodated I guess.

He advised that the fitting of moto cross tubes is not advised because of the thicker wall allows the building up of heat. I guess this would apply if you travelled a long way, at high speed, in the summer. Would not apply perhaps if you just pottered about in usual British weather! For moto crossing, perhaps the heat build up is accepted.

The 2.50/2.75 is I suppose the "small" 21" tube that has been mentioned.
 

Robert Watson

Well Known and Active Website User
VOC Member
Three things
All my 20" fronts are running 19" tubes. Some have done several 1000 miles and all with no issues. That's 3 votes for 19's

I also run Bridgestone motocross tubes in the Woolly one. 100/90 - 19 front and 120/80 18 Rear. 7000 miles in Australia two up with lots of luggage and 42C some days. They've done many many more miles than that, with never a failure. In fact - touching wood - since switching to these sizes I have had only one flat tire, and that was now several years ago, I went to Vancouver Island and stayed the night with my Dad (so probably at least 10 years ago) and got up the next morning to find a flat front tire. The tube had a wrinkle in it and after many miles had managed to wear through itself. So inflicted by me on assembly even though I blow up the tube after only installing one side of the tire. I also use talcum powder for assembly

I also run the valve stem nut up against the cap and remember only one time when I detected a tire moving, and that on a dirt bike with an almost flat tire. I do not run any rim locks
Robert
 

b'knighted

Well Known and Active Website User
VOC Member
new 20" (equivalent) tube bought this week

I feel it would be much better to stretch a 19" tube onto a 20" rim than to risk having wrinkles in a 21".
Last week at our old farts meeting Jack Edney, late of Sunbury? (not a Vin owner but known to many) arrived on his 1928 Velocette KSS with a flat and cracked rear tyre. The valve had torn out and the ancient sidewalls suffered from this deflation. As the tyre was 20" and rear 20" have been scarce for decades, I did not expect to see the bike back on the road for quite a while. He rode it in today on a brand new SM bought from Lambrook Tyres. I think he said it arrived with Central Tyre packaging. He said the numbers marked on the new tube were not what he was used to but that despite not being labelled as such, it WAS a new 20"inner tube, albeit for a 3.50 tyre.

I can find the tyre listed (http://www.classictyres.com/lambroo...rt=sort_size&mw=1&st_01=motorcycle&sf_01=type) but not the tube. They may be worth contacting.

Lambrook Tyres
C/O Vintage Tyres
National Motor Museum
Beaulieu, Hants SO42 7ZN

Tel: 0845 1200711
You can email them on: sales@lambrooktyres.com
 

Somer

Well Known and Active Website User
VOC Member
Another "trick" is to run a flap on your front fender.A lot of flats are caused by the front tire picking up a nail and "throwing" it into the rear tire.
 

wld50

Well Known and Active Website User
Non-VOC Member
Lambrook Tyres

I feel it would be much better to stretch a 19" tube onto a 20" rim than to risk having wrinkles in a 21".
Last week at our old farts meeting Jack Edney, late of Sunbury? (not a Vin owner but known to many) arrived on his 1928 Velocette KSS with a flat and cracked rear tyre. The valve had torn out and the ancient sidewalls suffered from this deflation. As the tyre was 20" and rear 20" have been scarce for decades, I did not expect to see the bike back on the road for quite a while. He rode it in today on a brand new SM bought from Lambrook Tyres. I think he said it arrived with Central Tyre packaging. He said the numbers marked on the new tube were not what he was used to but that despite not being labelled as such, it WAS a new 20"inner tube, albeit for a 3.50 tyre.

I can find the tyre listed (http://www.classictyres.com/lambroo...rt=sort_size&mw=1&st_01=motorcycle&sf_01=type) but not the tube. They may be worth contacting.

Lambrook Tyres
C/O Vintage Tyres
National Motor Museum
Beaulieu, Hants SO42 7ZN

Tel: 0845 1200711
You can email them on: sales@lambrooktyres.com

Reply just received from Neil of Lambrook Tyres to my query:

"Sorry but we are only able to supply 19 or 21" tubes.
Best Regards
Neil
<sales@lambrooktyres.com> "
 
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methamon

Well Known and Active Website User
Non-VOC Member
pressures

My contribution to this is:
Old MPH's are riddled at some point with extensive discussion about tyre pressures and I recollect that 22 PSI for the front was considered to be right.
I'll stick my neck right out now and say that in my opinion that is far too low (my Rapide from memory runs a 20 x 3.5" front tyre). At 22 PSI my tyre looks visibly flattened and the steering is heavy.
I acheive perfectly good handling and even tyre wear by inflating to 30 PSI.
The reason I mention this is that other than the points already made it is much harder for the tyre to slip on the rim and pull the valve out of the inner tube. I also run the rear at 30 PSI.
One further point is that the pressures do need checking regularly. My front always loses pressure over a couple of weeks and there isn't a puncture.
 

mr.hutch

Well Known and Active Website User
VOC Member
Blowouts!

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.
I've used "Ultraseal " in the tubeless tyres on my BMW for many years, also in the tubes on the outfit, without incident. ( fingers crossed)
I've proved it works to my own satisfaction, re the BMW, as having removed ,"a foreign body", from the running surface of the rear tyre, with total loss of air, but on rotating the wheel to spread the compound fluid found , re the instructions, that the the leak seald, at 42 psi., which was still ok after some 4000 miles plus and still OK until the tyre was changed. The claim that "Ultraseal" seals punctures without you knowing it, is quite credible.
Ok there are limits to the size of "objects" , but so far so good relative to the outfit's tubes.

This is a far different product to that offered back in my professional motocyclying days up and down the A12 in the 80's, when I had several horrenous incidents with products that guranteed , "no punctures", OKO is a name that springs to mind, one of many, a total waste of of money, and seriously dangerious!, if it's still available.
The trades description Act was not much in evidence then, but, hay ho! has anything changed.

This has nothing to do with security bolts, obviously, I do'nt have that problem.

Go carefully, mr.hutch :)

P.S. Hope I don't go out and find a flat tyre in the morning! :rolleyes:
 

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