standard hub spacing?

[courierdude]

i wanted to build up this sachs frame i have but ive tried a couple of rear wheels on and they are about a cm too wide for the drop outs/swing arm.

given that its a weird old bike and also been squashed on one side, big chain ring bent, derailleur hanger snapped, it could well be that the swing arm its self-straight as it looks could have been pinched..but it doesnt look like it

jst wondering if-on a mid 90s frame that there might be some obscure dimension to this particular bike?

 

[Stick Legs]

135mm rear.

some late 80's bikes and custom jobs ran 130mm as road hubs do but the industry pretty much standardised on 135mm rear and 100mm front by 1992.

Those are 'over lock nut' dimensions, so the 135mm will be the spacing between from the clamping surface of the hub to the other side.

Obviously most frame 'spring' a little, but only a mm or 2.

If a frame hasn't had a wheel in for a long time it can move, but don't be scared to ease it back a little.

 

[xerxes]

Re:

Some early MTBs had a 130mm spacing, but before the advent of modern through axle malarkey, most were 135mm.

However, there are quite a few "standards", such that using the word "standard" is a bit silly: https://www.sheldonbrown.com/frame-spacing.html

 

[courierdude]

Re:

lol i just measured up and im 120mm : /

was hard to see, given that chain stays can be asymmetric but the gap would be impossible to fill...unless you have a hub from the 1940s i could borrow?

thanks for the link

gonna have to buy that tool then
cheers

 

[xerxes]

Re:

gonna have to buy that tool then

What are you planning on doing?

Be aware that you cannot "cold set" aluminium. Cold setting, is essentially just bending the frame without using any heating it to soften the metal. This is fine for steel frames, you can bend steel around pretty much willy nilly and provided you stay within the point where steel cracks or tears, or in the case of a tube, creases and collapses, it's all good and you won't weaken the metal.

However, you can't cold work aluminium, if you bend aluminium too much it will crack and even if you stop before it cracks, you may have weakened it.

 

[courierdude]

i wouldve expective to see a fracture in it somewhere already to be honest to give me some sort of clue as to where the bend might be but there isnt anything to indicate such unless its just a nice long shallow sweep. yes i understand it would need heating up but if i cant find where its bent then i wouldnt know where to begin straightening it. i would end up bending it more than it already is and its not so nice that i would spend time welding up a mild steel jig...so i guess its strip its bits and off to the recycling tip : / bit sad as its quite different, uncommon if not rare and quite an early example of a 1.1/8 head tube and beam frame... maybe hang on to it until im really bored with too much time on my hands

 

[mk one]

I would have thought you could have seen the bend, if you measure from the top of the swingarm gap all the way along to the dropouts at regular intervals you should see where it is bent, but if you cant see it by eye then it probably aint.

I also doubt the top and bottom stay has bent, if you run a straight line, string or the like, parallel to each other from the dropouts to the front you should notice any twisting of the frame, again should see that by eye.

The option would be to replace the swingarm if bent, looks like a standard style and should be pretty easy and cheap to pick up a donor frame.

Mark