BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: AdrianW on 05 Oct, 2019, 08:29

Title: B33 - Progressive Fork Springs?
Post by: AdrianW on 05 Oct, 2019, 08:29
Dear All,
It's been a while since I was here but I could do with some help / experience..
Thanks to a local quarry my '54 B33 had an unfortunate meeting with a large rock strategically placed in the road by one of their lorries.. The good news is that I managed to stay on, the bad news a badly dented rim.
The fork seals had leaked for a while so the whole lot came off.. 

In true "while I am at it" style I wondered about fitting new forks springs. Mine are a slightly different length from both 65-5390 (correct ones) and 89-5036 ( that everyone sells for singles but seem really to be for an A10).
So, I wondered about spending a little extra on Progressive ones, either from Paul Goff or SRM..

Anyone have any experience here please?

Thanks,
Adrian
Bristol UK
Title: Re: B33 - Progressive Fork Springs?
Post by: JulianS on 05 Oct, 2019, 09:28
The springs 89 5036 are a replacement for the 65 5390 for the B series.

Service sheet from 1956 explains.

I use the progressive springs on my A10. They work OK.
Title: Re: B33 - Progressive Fork Springs?
Post by: AdrianW on 05 Oct, 2019, 17:05
Thanks Julian,
That's really helpful, explains why everyone sells the later item!!  Unless anyone can convince me the progressives are really worth the extra I think I'll stick with the standard items..

Cheers,
Adrian
Bristol UK
Title: Re: B33 - Progressive Fork Springs?
Post by: Mark B on 07 Oct, 2019, 13:14
I've not used progressive springs on my BSA but in my experience on other bikes they are a retrograde step. Far too springy at low speeds, leading to a pogoing sensation in towns and traffic (where the 'soft' section of the spring is used), and no noticeable difference from the standard ones at higher speeds. I put the standard ones back and everything felt much better.
Title: Re: B33 - Progressive Fork Springs?
Post by: AdrianW on 09 Oct, 2019, 13:03
Many thanks Mark..
I'll order some new standard ones...

Thanks again for confirming my thoughts..

best wishes,
Adrian
Bristol UK