Author Topic: tyre pressure  (Read 3652 times)

Offline townsends20

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tyre pressure
« on: 17.09. 2011 13:43 »
Hi,
     Still getting to know this rebuild 62 rgs. And now on the road I need some input on tyre pressure. I have fitted Avon road riders, the book pressure it says 20psi.(BSA)  the tyre's says 47psi, with these tyres I can see that 20psi is way to low so I am running at 35psi what do you think.
steve   :!
1962 rgs

Online bsa-bill

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Re: tyre pressure
« Reply #1 on: 17.09. 2011 14:17 »
I use speed master front and roadrunner on the back of my Flash for period look, I run them both on 30 lbs/ft, they must have softer sidewalls than back in the day, running at twenty is downright scary.

On my project I run AM20 rear (Venom) and AM18 front both at 30 also, but it hasn't covered a lot of miles as yet so remains to be seen if that is correct - great tyres though, handles nice
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline t20racerman

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Re: tyre pressure
« Reply #2 on: 17.09. 2011 14:18 »
35 psi is too high.  You want about 27/8 in the front and a couple more psi in the back. 20 is way too low, and please don't put 47 psi in - that is telling you the MAX pressure the Tyre can safely run at. You would get little heat in your tyre and no grip at that pressure.
1961 A10 - somewhat modified :-)
1980 TZ350 - lunatic Classic Race machine
1967 T20 Suzuki - heavily modified Classic Racer
1967 T20 Suzuki - pretty standard road bike
2007 KTM 660 SMC - fast and furious supermoto
Triumph 675 Speed triple
Ossa 250 and yet another T20 racer in bits both being built up

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Offline alanp

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Re: tyre pressure
« Reply #3 on: 17.09. 2011 16:46 »
I run my RGS at 22F and 24R. I ride faster than most classic riders as far as I can tell and have no problems with the Road Riders. They warm up nicely and corner really well. Too high a pressure won't flex the tyre enough to warm them up as quickly and can, in some circumstances, affect the way the tyre grips the road when cornering on less than flat surfaces since our suspension is pretty crude by modern standards and will bounce up off undulations more with higher pressures and reduce grip.
I ride solo and am 13 stone, but if you ride with a pillion I'd move the pressures up 2 or 3 pounds, especially the rear.
I suspect that there is no absolute right or wrong with these bikes and that there is a pressure range window from say lower 20's to around 30 where it will won't make much difference in reality depending on your load, riding style and road conditions.
Member of the 'Last of the Summer Wine Club - Jennycliff'.

Offline t20racerman

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Re: tyre pressure
« Reply #4 on: 17.09. 2011 17:43 »
That does sound too low to me alanp. Old thick walled speedmasters ran low pressures - hence the psi recommended by BSA, but no modern Tyre I know of should run at such low pressures now. Although not Tyre specific,look at this US Avon guide:

http://www.avonmoto.com/tech/tire-pressure-guidelines

I'd try it a little higher and see how it feels.

Might be worth an email to Avon - they are really good at customer advice on issues like this. Be bettter than us load arguing about it here!  *smile*
1961 A10 - somewhat modified :-)
1980 TZ350 - lunatic Classic Race machine
1967 T20 Suzuki - heavily modified Classic Racer
1967 T20 Suzuki - pretty standard road bike
2007 KTM 660 SMC - fast and furious supermoto
Triumph 675 Speed triple
Ossa 250 and yet another T20 racer in bits both being built up

"If I had all the money back that I've spent on motorcycles... I'd spend it all on motorcycles!"

Offline Beezageezauk

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Re: tyre pressure
« Reply #5 on: 17.09. 2011 19:50 »
I've been running with a combination of Avon Speedmaster on the front and SM Mk.2 on the rear for many years and cover long distances, mainly on the motorways.  But...I'm normally carrying full camping gear which is the equivalent of a small pillion passenger.

I found that as I ran my tyre pressures recommended by the book the rear tyre used to creep and eventually pull the valve out of the tube.  Over the years I gradually increased the pressures slightly and again the tyre creep would eventually occur.  Now, for the last 6 years I've been running at 28 psi in the front and 36 psi in the rear and haven't had the problem.

I suppose that tyre compounds have been changing over the years so you can't go by the BSA Manuals anymore.  Who knows...my settings of 28 and 36 may have to be increased even further in the future.  Time will tell.

Beezageezauk.


Offline alanp

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Re: tyre pressure
« Reply #6 on: 18.09. 2011 11:13 »
That does sound too low to me alanp. Old thick walled speedmasters ran low pressures - hence the psi recommended by BSA, but no modern Tyre I know of should run at such low pressures now. Although not Tyre specific,look at this US Avon guide:

http://www.avonmoto.com/tech/tire-pressure-guidelines

I'd try it a little higher and see how it feels.

Might be worth an email to Avon - they are really good at customer advice on issues like this. Be bettter than us load arguing about it here!  *smile*

Ok, I'll lift the pressures and check the result. It's curious though how well my bike handles running 22F 24R. Thinking about it, my inner tubes were marked for off road use so maybe they are thicker and stiffening up the side walls. I've not thought about that before. It out cornered my '06 BMW so felt that it couldn't be far off the mark, but I'll check.

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Offline BSA_54A10

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Re: tyre pressure
« Reply #7 on: 19.09. 2011 10:56 »
You run the tyre pressure that AVON the people who made the tyre recommend .
You run what BSA recommended if you are running NOS Dunlops stored at less that 30 deg C in a non oxadizing atmosphere protected from UV rays.
Bike Beesa
Trevor

Offline t20racerman

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Re: tyre pressure
« Reply #8 on: 19.09. 2011 15:50 »
I decided to email Avon technical department about this as it is an important safety issue that no doubt will rise again. I got the following answer this morning after asking about Classic bikes, and the A10 in particular:

Quote
Hi Adrian,
We would recommend 25-28 psi front and 28-34 psi rear for classic bikes.
I would suggest 28 psi front and 30 psi rear for your bike.

Best regards,
Peter J McNally
M/C Technical Product Manager
01225 357753
www.avonmotorcycle.com

So folks, if running Avon Rideriders, use 28psi front and 30 psi rear as a good starting point - and higher with a pillion and gear I presume.
 *smile*
1961 A10 - somewhat modified :-)
1980 TZ350 - lunatic Classic Race machine
1967 T20 Suzuki - heavily modified Classic Racer
1967 T20 Suzuki - pretty standard road bike
2007 KTM 660 SMC - fast and furious supermoto
Triumph 675 Speed triple
Ossa 250 and yet another T20 racer in bits both being built up

"If I had all the money back that I've spent on motorcycles... I'd spend it all on motorcycles!"

Offline alanp

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Re: tyre pressure
« Reply #9 on: 19.09. 2011 18:55 »
I decided to email Avon technical department about this as it is an important safety issue that no doubt will rise again. I got the following answer this morning after asking about Classic bikes, and the A10 in particular:

We would recommend 25-28 psi front and 28-34 psi rear for classic bikes.
I would suggest 28 psi front and 30 psi rear for your bike.
Best regards,
Peter J McNally
M/C Technical Product Manager
01225 357753
www.avonmotorcycle.com

So folks, if running Avon Rideriders, use 28psi front and 30 psi rear as a good starting point - and higher with a pillion and gear I presume.
 *smile*


Thanks for your input, that's what I'll put in mine. I can hardly wait for the rain to stop to compare. I could be a while!!!








[/quote]
Member of the 'Last of the Summer Wine Club - Jennycliff'.

Offline MG

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Re: tyre pressure
« Reply #10 on: 19.09. 2011 21:44 »
Interesting thread, on whatever bike I rode, I have always liked using a little bit more pressure than recommended, also in the modern tubeless things.

On the As I have ended up with 31psi front and 35psi rear, that suits me best (Avon RoadRunner rear, Metzeler Perfect ME11 front). Significantly lower pressure (25-26psi) feels very spongy and lacks feedback imo.

But that is really down to personal taste I guess.
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