Riv Silver brand crank on Crust LB?

[kw]

Hi all,

I'm planning to use a Silver3 crank as a 44/28 double on my Lightning Bolt with a 9 speed cassette. I'm wondering if anyone has this setup and what BB spindle length you're using?

Thanks!

Ken 

[tnort...@gmail.com]

Not exactly an answer to your question.  But I  have accumulated old bb in different sizes to use to "actually " determine the correct chain line. It helps that I work PT in a bike shop and can grab old ones!

Tom

NE Ohio 

[Mark in Beacon]

I would go with what Rivendell says. A 110 bottom bracket will get you a 45mm chainline at the middle ring if you are running it as a triple or with a chain guard outer. I would start around there, maybe try a 107 to move the chainline in a bit for the double, . Call Riv if you are not sure. Doesn't have much to do with the Crust.

[satanas]

Many 110mm BBs (i.e., Shimano) are 3mm longer than 107mm on the LHS, but the same length on the RHS = same chainline.If it was me I'd want to measure the BB before committing to it. YMMV.

Later,

Stephen

[Will Mill]

Hey Ken, 

Short answer: I'd probably go with 110mm BB. 

Longer answer: I ran the Silver1 42/28 on my Lightning Bolt with a 68x107 mm BB and 9-speed cassette... and the chainline and Q-factor were spot on. Your Silver3 (44/28) is a different crank, and people (e.g., Riv Owners bunch) usually seem to run it with about a 110 mm BB, so it may not land in exactly the same place with the same 107 mm spindle.  

Will in NYC

[Kenneth Wiss]

Thanks all! 

I'll start with a 110mm BB and see how that works.

Ken

Brooklyn, NY

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[Ken Freeman]

I intended to share these thoughts with the group earlier, but I’m home caregiver for my wife who is an Alzheimer patient, and keeps me hopping!

Last rewarding fix I did on a bike was to salvage a 1952 Rudge Aero Special.  Identical to the Lenton Sport for 1952, same assembly line, parts list, and parts bins.  Nottingham plant sound them globally in four different branding, depending on where sold. Brands are Raleigh, Rudge and two others not well-known to me.  I think Humber was one of them.

I damaged the original cotter spindle pulling the arms off for overhaul. I ended up able to replace the whole cottered Raleigh Industries steel chainset with a TA 5-vis set of arms and  TA BB parts including BB cups.  I had to search for a 44 or 46 tooth track-width chainring as now used for track.  I found the TA chainset, a 48 tooth Al ring, and a few TA cotterless spindles and some TA bearing cups.

The TA cups threaded into the BB perfectly, with the bearing balls and the TA spindle matching perfectly. A test fit of the and  If the bearing cups thread the frame, place the bearings in the same place as did the original Raleigh Industries parts from 1952, then there is a real good chance the TA set of parts will be a good fit.  So my chain line is 45mm front ring and rear sprocket, my rear dropouts are aligned and their offsets are balanced.  The right pedal offset is 50 mm and the left is 55 for a very small Q factor of 102 mm! 

The alignment also depends on dropout alignment and if the chain stays are aligned nd offset the same.  There may also be spindles which match the TA crank arms but have different length drive side and non-drive side stubs.  This is something to watch out for in a nice old vintage frame like mine.

 

Ken Freeman
Ann Arbor, MI USA

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[Brad]

It may just be my quirks, but I have gone wider than recommended with my Stronglight Impact cranks.  I think they use a related forging.  Here is my rational beyond a bad experience at 107.  Which rear cogs do you ride most often?  That is where your chainline should be.   If you ride the middle cogs front and rear, then great, line up the usual way.  8, 9, 10, 11, etc. cogs the gaps get thinner and the chains more flexible.  see https://www.sheldonbrown.com/cribsheet-spacing.html

A difference of 3mm on the chainline further out is less than the space between cogs.  On a freewheel a difference of 6 is just slightly more than the space between cogs.