Harry Hall rear spacing options

[culleyh]

Hi
I've got a classic Harry hall frame I'm looking to rebuild into a useable classic.
Confusingly the rear dropout is spaced at 122mm and the 27" wheel set that it came with is a helicomatic rear hub / cassette which also appear to have been made in the odd oln size.
Single speed isn't an option or of interest where I live so I'm looking for suggestions to achieve a decent gear range with this dropout spacing. But guessing going up to 130mm may not be a realistic option?

 

[Little Al]

6 & narrow 7 speed screw on blocks require a rear drop out spacing of 126 mm.

 

[culleyh]

Re:

Yes that's the weird thing as the helicomatic hub is 6 speed, yet the dropout is relaxed at 122mm and the hub is a loose fit when installed! Think I might have to bite the bullet and try to cold set the frame as don't really want to spend a fortune getting a frame builder to do it

 

[Midlife]

You should be able to spring that to 126mm with your thumbs putting a 126mm hub in?

Shaun

 

[Cefnbikie]

In the early 1990s I fitted out a couple of wheels to take Sachs Maillard 7-speed freewheel bodies (the 7-speed bodies had seals whereas the 6-speed didn’t) fitted with 6 sprockets. This combination caused slight chain rubbing on the chainstay, so I had to space out to 122mm OLN (and re-dish the wheel very slightly), and slightly spring the rear dropouts. (Springing the rear dropouts too much can cause problems with the dropouts no longer being parallel, and make axles more prone to breakage)

Interestingly, the Sachs freewheels were marketed as being narrow, and they were slightly narrower (about 5.3mm spacing between sprocket centres) than a normal 5 or 6-speed (5.5mm), but slightly wider than a Suntour Ultra 6 (5mm). The freewheel that I use for general riding is 15-28T with, at present, 39-52 chain rings giving 36 to 91 inch gearing. Nowadays, I avoid the steepest climbs and am now considering a chainset with smaller rings.

Personally, I have always ruled out cold setting the rear dropouts on any of my frames, as I think that cold setting can unduly stress the brazing of the chainstay and seatstay bridges and cause weakness. One could clamp the bridges with preformed wooden blocks when cold setting, but there is still a risk of causing a slight fold in the stays themselves, especially in the area around the indentation that gives chainring clearance.