I have only just dashed back from ameeeting and am now trying to find some relaxation by reading the Clasicrendezvous List. So far I have read only a selection of contributions, but felt that I might be able to explain why th is type if horizontally rear-facing drop-outs were used. If someone has alr eady put forward this expanation please accept my apologies because I haven 't yet had time to read all the contris yet.
Some members have correctly stated that the long rear slot permitted the ra pid change of gear ratios, by replacing the single sprocket...usually a fix ed gear one, the chain taking up the slack of the chain or vice-versa , hence the longer than usual slot..longer than those on long Campag forward-facing gear drop-outs.
This type of drop-out was particularly popular in the 40s through to the la te 60s in the UK when the road-track fixed gear commuting bike was popular, the bike also doubling up for a spot of track racing, or even for competit ive roller racing during the winter wet season, in the club-house.
I can't speak for this type of drop-out in the States but in the UK, where the use was predominantly with fixed gear it was customary and indeed essen tial to use the drop-ots in conjunction with wheel/chain adjusters. These w ere pressed steel affairs fairly long with an eyelet that slotted over the non-Q/R axle. On to this eyelet was welded a threaded rod that passed throu gh the centre of a U-section piece of steel that located up against the ver y end surface of the drop-out
When in place the wheel would be pulled rearwards until quite tight and the track nuts tightened, but not fully so. The mechanic would then set his sp anner of the small nut at the end of each adjuster rod , gently pull the wh eel backwards and in this way gradually fine tune the tension of the chain, until it had just the correct tension., and then lock the track nuts up firmly. If the frame was slightly out of track and the wheel not exactl y central in the stays or the wheel itself not built true, the adjusters co uld compensate as necssary. It was an incredibly accurate way of tensioning a chain and also centering the wheel. The fact the the adjuster butted ver y hard against the end of the drop-out when the chain was fully tensioned r endered it impossible to pull the wheel over against the stay even under sp rinting conditions.
Several models of track-ends made in the UK during that period appeared to be very chunky and had two small spigots pressed or forged or machined into the very end of each drop-out. These spigots located on the inside faces o f the U-section part of the adjuster and virtually locked the adjusters fir mly into position.
A similar but smaller ajuster was very common on single speed roadsters and kids' bikes for a very long time.
Norris Lockley Settle UK
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