The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: RDfella on 06.03. 2021 18:14
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New Suzuki rear wheel 49t sprocket arrived two days ago, so I turned the teeth off my hub (BSA '62 FWH) and welded it on. Decided to replace the sprocket hub bearing at the same time and duly looked for 89-3022. Now, given imperial bearings are less common than metric, they are usually more expensive. Even moreso when they're C3, as is the case here. Because the sprocket bearing is a press fit in the hub and, as a bearing will usually close up by around half the interference fit (ie an interference of .001" will cause the bearing outer race to 'shrink by .0005") a bearing with extra clearance is required.
For those not familiar with these things, ball and roller races are available with varying internal clearances depending on application: C denotes tighter than usual clearance, C2 is normal, C3 extra clearance, C4 even more and C5 max clearance normally available. A bearing with extra clearance will be marked as such. In the case of C3 - the most commonly used extra-clearance bearing - by three small circles etched on the outer race. Given many bearings advertised online as being 89-3022 were in the £5 - £10 price range, I wonder how many were actually the correct part and how many just run-of-the-mill standard ones? The cheapest genuine C3 bearing I could find was £18.
And the sprocket - what's going on with UK manufacturers? Are they trying to price themselves out of business? Was quoted over £100 by a firm I used to use fairly often years ago, but eventually got a (new) sprocket from Italy for less than half of that, including postage.
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And the sprocket - what's going on with UK manufacturers? Are they trying to price themselves out of business? Was quoted over £100 by a firm I used to use fairly often years ago, but eventually got a (new) sprocket from Italy for less than half of that, including postage.
"No call for them pal"
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G'day RD.
The last proper C3 bearing I bought for the Cafe crank was nearly $100au.
When racing the A7SS, I turned off the teeth on the sprocket. Then got three alloy sprockets of different tooth counts. Bored them out and scotch keyed them to the inner.
Cheers