The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: mikeb on 30.08. 2020 08:50
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I’m trying to fit a ‘69 triumph TLS front wheel / TLS brake to my 1961 super rocket which currently has the 8” full width hub. The goal is swap the whole wheel and keep it reversable. But the ‘69 Triumph spindle measures 7” wide whereas the a10 is 7 3/16”.
I’ve read a bunch of threads saying sometimes contradictory things, probably as there’s a lot of variance between models. Ie: it should just bolt on (or not!), different models have different width spindles, the spindles are interchangeable between a10 and between tri-bsa tls hubs (or not!), the a65 spindle is the same width as the a10 (or narrower!). Solutions appear to be:
a. Use the a10 spindle – but will it actually fit to the triumph hub???
b. Use an a65 TLS spindle – but will it fit the triumph hub AND is it the a10 width?
c. Use ??? spindle and re-machine some grooves for the clamp bolts. but what spindle??
d. just pull the folks together – no, I’m not doing that.
1. So can someone suggest what the easiest way forward is here?
2. there’s also mention of some people making a spacer (on the RHS only?) to compensate for the extra width. Can someone clarify this please?
FWIW I know I’m also up for building up the slot on the brake plate to mate to the slider lug, kinking the right mudguard stay and fitting the split brake cable (the one for the front brake switch).
Thanks
Mike
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I had a problem with the front forks on an A10, in that when I installed the wheel (8 inch fwh) the forks had to be flexed slightly to fit the caps. this caused the suspension to bind up. long story short, it transpired that the wheel was a Triumph one. Fitting an A10 spindle ( BSA and Triumph used the same hubs ) sorted the problem, The previous owner had owned the bike for about 20 years and always wondered why the forks didnt seem to work
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thanks rayjay. so to clarify: was the triumph FW hub a TLS? and did the standard a10 spindle just fitted to it?
anyone else have thoughts on spindles and hubs between a10 and triumphs tls?
cheers
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The A10 spindle does fit the BSA/Triumph full width hub with verticle spoke flange on the brake side. My A10 been using that arrangement since 1976.
That hub was used from 1966 for the big Triumphs but be aware that the Triumph forks to 1968 have 6 1/2 inch inch centres. For 1969 season Triumph changed to 6 3/4 inch centres. The A10/A65 has 6 3/4 inch centres.
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Hi Mike,
I remember fitting a triumph front wheel to a 69/70 A65, had to swop spindles
No knowing the year of the wheel tho,
You will just have to strip got both wheels and work out how it will go together
John
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There's a spare a10 front hub here waiting for you to strip the axle out of . Either Sunday or the next clubnight. I've got a shelf of those (7" & 8") I'd like to get rid of.
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Thanks guys - that's super helpful.
Julian - with those different yoke widths, do you recall if a spacer is required when fitting those later triumph/bsa hubs to the a10 (with a10 spindle)?
Tim - I'll see you Sunday and look forward to relocating some more bsa treasure from your shed to mine!
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My conversion was quite easy - bought the hub, fitted the A10 spindle, no extra spacer, took hub complete to local dealer (then Ray Fisher in Christchurch) who built the wheel (he did not need any off set etc he had the details to hand) The wheel fitted perfectly but then had to deal with the problem of the A10 fork lug not being long enough to engage with brake plate. Had the plate build up with ali weld and filed to fit the fork.
I have seen it suggested that a spacer can be fitted between the shoulder of the spindle and the brake side bearing to move the whole assembly towards the fork, but looking at my setup it does not look like there is enough thread on spindle to allow the large nut to be fitted.
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Thanks Julian - that's very encouraging
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The 69-70 Triumph TLS backing plate requires about 1/4 inch greater clearance due to the different design than the 68 TLS...
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I've now got the wheel test-fitted and the brake plate waiting to get the lug built up. turns out (as usual) I was overthinking it. after hours of internetting and measuring some spindles from RR, the short version is just use your existing a10 spindle on any TLS triumph/bsa hub/plate when the spindle you have is too short. For the next person facing this, here's the long version:
Summary of fitting Triumph/BSA TLS plate/hub/wheel to late A10 forks:
- Make sure the spindle you use is the right length (width) for the a10 forks with the grooves in the right place.
- There are two main different spindle lengths encountered. various internet sites will state different lengths for each. also, there may also be a third even-shorter spindle used on smaller triumphs. And BSA and Triumph fork lowers do not have the bolts in the same position creating more variations.
- The A10 spindle (42-5824) does fit the BSA/Triumph full width hubs with vertical spoke flange on the brake side. All these full width hub variants use the right bearing fixed by the retaining ring and the floating left bearing secured by the dust seal and circlip.
- My A10 spindle (42-5824) measure 7 1/4" long with groove centres at approx 6 1/8"
- There are narrower spindles (37-1641 / W3641) on 65-68 triumph hubs which match their narrower 6 1/2" fork spacing. I measured these as 7" long with the groove centres approx at 5 7/8". To fit to the a10 just replace these spindles with an A10 spindle. Some people talk of re-machining the grooves that locate to the end-cap bolts, but unclear if the spindle would be long enough.
- The a65 hubs/spindles should fit the a10 as all bsa forks were 6 3/4" spacing. BUT the 1968 A65 used narrower '37-1641' (triumph W1641) spindle to accommodate the 'new' triumph hub/TLS into the 'wider' bsa forks by using offset end caps in the sliders - THAT YEAR ONLY. (So note the '68 A65 forks are unique to that year).
- Some people talk of using spacers to accommodate the narrower 65-68 triumph hubs but most don't. The only thing a 1/4" spacer may do is sit inside of the right hand anchor plate nut to ease its tightening.
- Some people suggest the triumph '69 TLS plate (for the 1969-70 6 3/4" spaced forks) is wider than the '68 plate but others say the plates are the same width. The triumph '69 TLS plate has the more agreeable brake cable angle BUT it MAY be easier to fit the later a10 mudguard stay with the 68 plate.
- The 69-70 triumph hubs and their spindles should fit the A10 forks, but some (maybe early) 69 hubs appear to have the narrower '1641' spindle which will need changing to the a10 spindle.
- The 70- conical hubs were completely different spindles and internals. Don't go there on a10 forks.
if you see anything inaccurate in this summary let me know
cheers
EDIT: pic added showing a10 vs shorter triumph spindles
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i was clearing photos off the camera and thought I'd add this one to this post for the next person trying to visualize how to build up the slot for the fork lug when fitting a later tls brake plate to an A10. from what i've seen, the one shown has a lot more metal added than some others (that work just as well). you can get the idea of building the slot out 1/4" further and some strengthening.
also FWIW the easy way to get the mudguard stay around the grease nipple is just splay it out sideways using am old nut as a spacer and a longer bolt. no bending required and 100% reversible. and my a10 brake cable worked fine albeit with a slight extender at the lever end to make it 1/2" shorter.
I'm loving the TLS brake *smile*
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Pretty sure 1969 was the first year for the front brake light switch on bonneville