The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: BrianS on 03.01. 2017 10:02
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I had an email reply this morning from Ashley Vowles at Avon recommending tyre pressures for my 1955 BSA A10 650cc Golden Flash (swinging arm model).
For the Avon Safety Mileage MkII rear tyre 3.50x19 he recommends 30 psi
For the Avon Speedmaster 3.25x19 front he recommends 26psi.
Both tubed type.
He recommends increasing those by 1-2psi to carry a pillion.
Brian
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yes I agree with those pressures, when I first rebuilt the Flash I followed the BSA book - not good.
Modern tyres (even the old names) require higher pressures, think I read they are made differently now.
Tubes are something I have a thing about, rear has never had a problem but the front always has a very slow leak, like the three tubes I've put in are all porous, and yes I have checked the spokes and changed the tyre, could be I'm just a crap tyre fitter of course
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http://www.a7a10.net/forum/index.php?topic=1538.0
It was the above thread that lead me to this forum and glad I did too *smile*
Having bought my A10 in sept last year and it being the first time on a Brit bike for over 40 year I thought *eek* WTF have I bought ! had already checked tyre psi and correct to manual that came with the bike but it was all over the road and crap cornering, googled the tyre pressures for the bike and up came the above thread, straight to the garage and pumped up the tyres to said pressures and a pump or 2 for the wife on the back and Hey Presto it was a different bike to ride !
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WOW ! ! ! ! My Haynes manual says, 18 pounds front , 20 pounds rear, from what I read here, that has to be way too low ! !
Good old Haynes manual, 47 to 62 A-7 and A-10 bikes. Just another one of the many miss info`s in Haynes. ! ! ! !
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WOW ! ! ! ! My Haynes manual says, 18 pounds front , 20 pounds rear, from what I read here, that has to be way too low ! !
Good old Haynes manual, 47 to 62 A-7 and A-10 bikes. Just another one of the many miss info`s in Haynes. ! ! ! !
Bill,
its not that Haynes was wrong for the tyres of the day (back in the sixties), but that todays tyres require much higher pressures even if we are choosing old school patterns. 25-30lbs is a good starting point. The new tyres are made with modern compounds and with modern methods irrespective of the tread still being circa 1950
Tim
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[quote author=bsa-bill
Tubes are something I have a thing about, rear has never had a problem but the front always has a very slow leak, like the three tubes I've put in are all porous, and yes I have checked the spokes and changed the tyre, could be I'm just a crap tyre fitter of course
I bought some pure rubber tubes and they leak. Apparently this is a good feature. As I always fit new tubes to new tyres, next tubes will not be pure rubber...
And Haynes manuals should not be relied upon, just good to have the specs all in one place
Cheeers TC
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I like a little more in my Avon AM26 Road Riders. 32 in front 36 in back. If it's wet I drop 2 out of each.
Cheers
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I like a little more in my Avon AM26 Road Riders. 32 in front 36 in back. If it's wet I drop 2 out of each.
Cheers
Funnily enough those are the pressures I guessed at before I heard back from Avon and, with two up, they seemed to work just fine!
Probably a tad OTT for going solo though.
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Hi All
next tubes will not be pure rubber..
Tomcat,
I only use quality branded, Michelin, Metzeler, or Continental tubes
All these seem to lose pressure over time
It makes you check the pressures are correct regularly *good3*
Back in 2001 I had a really nasty "Off" when a synthetic rubber tube split in the front wheel *warn*
I think a bit of chrome peeled and punctured the tube ?? but instead of losing pressure over time
it split along a 6in. length *pull hair out*
John
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I wouldn't even consider using a butyl tube after seeing the way they tear. I just put up with the rubber.
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They usually only split when they have been overinflated.
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32/36 seem rather high Musky.You must have a good back.
I usually run around 30 both ends but will give it a shot.
Cheers.
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G'day HD.
Ha, my back is rooted (L4 L5 S1 fused). I've tried lower pressures and they feel (to me) a little washy. With the pressure I run the Avon Road Riders just fall into corners, I luv'em.
Cheers
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I also work on running ~28/~30 and it's fine, but as my tubes also rapidly lose pressure, I sometimes go a bit extra, so it's a couple of weeks before they get down to 15, whereby they feel a bit 'buckety' (I don't check them every outing- most days @ short notice)
The good thing about adding air, is they feel like new tyres again *woo* *woo*
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Just discovered mine were flat, the only tell tale was that the back squealed on braking. Filled them up to 22 and 30 and the only difference was it was a little bit more feel through the bars. Avons front and back. My old RE Bullet just stops lying down round corners when the tyres are low but no such indicator on the SR.
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Continental tubes my group had were very porous and needed air every couple of weeks.
We've all switched to Michelins and problem has disappreared
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G'day Slymo.
At those pressures mine would handle like a wet sponge! Which Avons are you running?
Cheers
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RGS-Bill - and Haynes tell us to shim both sides of the crank! And now I find modern Haynes manuals next to useless as clearly whoever writes tham hasn't done the work suggested.
As for tyre pressures, there are a lot of variables to take into account. I've found bigger rims (eg WM3 instead of WM2) need less pressure as the tyre is less rounded. Run 20/20 on my M21 (rigid) and just a tad more on the GF (S/A) My Firestorm is 36/42 so I'm slightly surprised at 30 being suggested for the A series. Although years ago I recall running pressures about 10psi above normal increased grip for rally cars on tarmac.
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Erm no actually re reading my post 30 was a typo, Ive got 34 in the back but do have 22 in the front. No problems with cornering but then I didnt really notice that they were down in the low teens prior to the top up other than the squealing. Also I inflated them at the local petrol station and that guage has been thrashed, dropped and driven over so Its at best an aproximation of inflation.