cold setting a steel frame- how far can you go?

[bkaldorf]

so I'm starting on my first build, I have a 52 schwinn dx frame that I would like to add a 3 or 5 speed to. right now the hub spacing between the dropouts is 110mm. Is it possible to cold set the frame to fit something like a 5 speed, which from what i'm reading has a hub spacing closer to 120mm or if I'm going with a more modern hub, even closer to 135mm? Is that pushing the rear triangle too far?

 

[Captain Awesome]

Done properly 135 is totally possible. Just watch the seams where welded/brazed. May have to "align" the dropouts back to parallel if they should V outward

 

[rickpaulos]

135mm spacing is typical for modern road or mtbs with 8 or more gears in the back end. Trying to add 8,9 or 10 speed gearing leads to many other issues. More gears = skinnier chain which means you need skinnier sprockets which means a 1 piece to 3 piece bb adapter. There is a distinct lack of 1" clamp sizes for modern front derailleurs. The chain stay length may be too short to accommodate the wide chain angles without grinding on the front der cage. Most 8,9,10 speed rear derailleurs are made for dropouts with hangers. An old cruiser frame would use a der with a built in claw mount.

keep it at 7 or less gears for fewer issues. There have been many 7 speed cruisers over the past 20 years so there are parts for that.

Some IGH makes offer the same hub in different spacing. Hold off on respacing your frame until you have your hub/wheel in hand to measure. Freewheel hubs can have their spacers moved around to fit just about any frame.

A 52 Schiwnn should be a brass fillet brazed frame. Off hand I don't remember what year Schwinn switched over to the EF frames. As stated above 110 to 120 is no problem. Low-carbon steel frames can usually take quite a bit of alteration. I've respaced many steel frames. By far the toughest was a cromo race frame. Most gas pipe frames are all to easy to bend. With the curved tubes on the Schwinns, you often need to run full length cable housing which adds a lot of drag in the cable. I never liked full housing as it really degrades shifting performance. Higher grade cables and housing can sure help. Using cable stops with open cables on curved tubes leaves the cables sticking out more which are easy to snag.

A note on front wheels. Many old bikes had 5/16" axles. Now days most front axles are 10mm. You may need to file out the fork ends a bit so the axle will fit in the slot. Just try to keep your filling even, front-back and side-to-side so the wheel stays centered. Use a hand file(s) and take your time. Power tools will overdo it too quick. 100 mm is the modern width standard but many older bikes were a bit narrower. Removing lock washers or using thinner lock nuts can help them fit better so you don't have to wrestle the wheel in/out. Bending forks to fit wheels isn't a good option ever.

 

[bkaldorf]

thanks guys for the replies! I guess my goal is to make a 24" krate style bike so definitely leaning towards a 5 speed. The area at the headtube where it meets the downtube and toptube is curved, is that an indication that it was made using electroforging?

 

[Wildcat]

I put a Nexus 3 speed on my 53 Schwinn with no problem.

I think it was 120 or 130mm, a lot wider than the original spacing of the dropouts.

You should use something widen the stays when you know the exact width. Probably the best way is like this pic shows, using a threaded bolt to widen it. An old axle would work if it's long enough. That way you can be sure the dropouts are exactly perpendicular also.

 

[MattiThundrrr]

Lol @rickpaulos said it all. But he said it with pictures here:
https://ratrodbikes.com/forum/threa...ce-between-rear-dropouts.114609/#post-1193010

 

[MattiThundrrr]

Rick also shared his string method:
"
You can used the "string method" to see if you got both stays moved equal distances.

Run a string from one rear dropout, around the head tube, and back to the other dropout. Pull the string tight. measure the distance between the string and the seat tube, compare both sides to see if they are close.

Many frames have indentations in the stays for chain ring or tire clearance so the stays aren't equally strong. As a result, your method can move one side more than the other.

If the string method is off, your bike will ride down the road crooked. The rider won't notice (much). it will slow you down a bit as the rear tire is crooked in relation to going straight ahead. You can put the wheel in the rear in at an angle to try to make up for it but then it rolls offset from the front wheel."
Totally not stalking you Rick, you just give good advice

 

[Karate Chicken Industries]

Skip the cold setting and use an old bolt on freewheel hub by adjusting the spacers as needed. I've done it a few times now and am headed into the coolness of my garage in a bit to get another five speed cruiser rolling. It's cheap and easy if you build wheels or have a competent wheelbuilder.

 

[us56456712]

You can make a frame alignment gauge from wood. This is better than the string method, I always get a little off using string. I made mine out of welded square tubing, because I got tired of making a new wood one when I needed it. You can use threaded rods or old axles that fit the rear drops to check for alignment after spreading and use the ends of the rods or axles to bend them parallel.

My frame alignment gauge.

Rear fork/drop out alignment, not parallel here.

Same bike as above bent back with the rods to parallel.