The BSA A7-A10 Forum

Bikes, Pictures, Stories & more => Chat, Offtopic, Meetings & Everything Else => Topic started by: dave55 on 07.06. 2017 15:12

Title: Maximum Carrying Capacity
Post by: dave55 on 07.06. 2017 15:12
Maybe an odd question but i am sure someone will know the answer, is there a maximum carrying capacity for a A10 plunger GF, meaning total of rider, pillion and any luggage for touring .
I wouldnt want to overload the old girl and bust the tyres or worse being as the tyres are skinny things unlike the rider  *eek*
Or do you take the max load written on the tyres and divide by two as being the max load ?
Title: Re: Maximum Carrying Capacity
Post by: duTch on 07.06. 2017 22:13

 There's only about 2" of travel in the load springs (total).

 I had springs made for mine, and I doubt they're same as standard (I know they're not), But I think about 400 kg will push them to the limit (fully compressed). I think that's both springs together.

 Had a late call for a job, but can check  my figures later.

 In your case, it would depend on the position in travel of your axle, unladen at rest (off centre stand).

Title: Re: Maximum Carrying Capacity
Post by: muskrat on 07.06. 2017 22:29
G'day Dave.
The wife and I weigh 200Kg plus another 20Kg in luggage on the A7 plunger. The sprung saddles worked overtime!
Cheers
Title: Re: Maximum Carrying Capacity
Post by: dave55 on 08.06. 2017 10:31
Thanks for the replies , mine has a dual seat but according to the wife its 4inches  too short ! but that's another story  *eek* We have used the bike a fair bit last year on short runs and never felt as though the suspension was bottoming out , just a bit like a gondola in the wind  *smiley4* I checked the tyres last night and the front is  DUNLOP GOLD SEAL K70  3,25-19   and this has no load marking on it ( looks old and too big and square so will change soon )     rear is AVON  S.M  MK2    3.50 -19   load marking says  MAX LOAD 230KG AT 36PSI COLD......................which by my reckoning is 36stone.  ;)So if the tyre says that and a new front would be similar maybe it would be ok at 20kg less than Musky ????......but I will tell her we are on the limit then she cant stuff 6 stone of clothes that wont be worn  in a set of panniers  ;)
Title: Re: Maximum Carrying Capacity
Post by: Klaus on 08.06. 2017 11:19
And tell your wife no hairdresser, curlers, stilettos and so on *roll*

This will save a lot of whight at the luggage *yeah*
Title: Re: Maximum Carrying Capacity
Post by: dave55 on 08.06. 2017 11:31
Good point Klaus  *good3*
Title: Re: Maximum Carrying Capacity
Post by: jachenbach on 08.06. 2017 12:54
The tire max load is definitely not the way to determine max load for the bike. The tire manufacturer has no control over what bike their tire is on.
Title: Re: Maximum Carrying Capacity
Post by: dave55 on 08.06. 2017 17:42
So what is the way jachenbach? Is there a capacity printed on a spec sheet somewhere or a magic formula to work it out, I just don't know and would like to? All I know at the moment is the tyres according to Avons and Dunlops documented load sheet I have found this afternoon says the tyres are good to go...........But I would like to know about the rest of the bike ?
Title: Re: Maximum Carrying Capacity
Post by: JulianS on 08.06. 2017 18:35
I have never seen anything from BSA (or anyone else) concerning maximum loading. I do not think there is a magic formula and ultimately its up to the rider to ensure his bike is safe.

Many of these bikes were attached to large sidecars carrying heavy loads of passengers and luggage. The cycle was clearly capable of taking high loads, though your hear reports of broken rear wheel spokes.

To cope with the sidecar load they were fitted with sidecar strength top springs in the plungers and sidecar strength fork springs.

Title: Re: Maximum Carrying Capacity
Post by: bsa-bill on 08.06. 2017 19:51
Quote
do you take the max load written on the tyres and divide by two as being the max load ?

Problematic that one I think as it assumes equal load on both wheels at all times, not that I've ever seen a A7/10 dp a wheelie with two up *smiley4*
Title: Re: Maximum Carrying Capacity
Post by: jachenbach on 09.06. 2017 01:10
I would recommend checking sag at both ends with whatever load is typically to be carried. About an inch on the forks should be a good starting point. The plunger rear, I'm not so sure. I would think no more than 1/4 of the available travel from full extension to bottomed out.
This should give reasonable handling. The frames on these bikes are pretty stout, so I doubt breakage will be an issue.
Title: Re: Maximum Carrying Capacity
Post by: muskrat on 09.06. 2017 08:48
Ha, hay Bill, it's easier two up!
The problem I had with too much weight on the plunger is the rear section of frame twisted. the plunger unit was 3/4" higher on the right.
Cheers
Title: Re: Maximum Carrying Capacity
Post by: bsa-bill on 09.06. 2017 09:24
Quote
Ha, hay Bill, it's easier two up!

True - I realised that as I posted  *red*
Title: Re: Maximum Carrying Capacity
Post by: duTch on 09.06. 2017 09:50
 So I got stitched up with work, and haven't found those figures yet, but mine are maybe not 'too' far from factory spec.

 Nothing to do with tyres here, but  From memory Plunger Rigs are ~ 420ish Lbs/ ~190Kgs total dry weight. Mine is slightly lighter, and roughly 80/110 Kg Front/Rear- I think from memory.

 so already there's 110 Kg of bike on the rear, and as you load it, unless you add any weight to the front, most of it (rider + pillion=80kg+70kg) will be all on the rear so by the time you account for road undulations/craters, you only have about 130kg/inch of spring to do the soft ridie bit.....


 Really dunno, but am curious to see how it goes- just be prepared to act like the Jetsons or ship-wreckees, and jettison stuff