I am getting a lot of sway in my rear rack. Any suggestions for getting rid of this? I have a 100mm fat bike frame with this rack:
amazon.com/gp/product/B005M9CQTC/ref=od_aui_detailpages00?ie=UTF8&psc=1

is it steel?
Any triangulation you can add from side to side would be good. Even braces from one side to the other.

https://www.amazon.com/Minoura-Gamoh...+Rack%2C+Black

Yep its steel. Any suggestion for brackets? Or are you thinking I should bust out the welder?

I assumed you posted in framebuilding because you could weld or braze.

I think a flat plate bolted between the stays on opposite sides would probably be a good start. How much clearance is there between the rack platform and the tire?

I agree completely that without and triangulation sway would be expected. It's sad how many racks don't take this into account. Andy

I could get my hands on a welder if needed but was trying to see what I could do without one. I saw a similar post saying to ask in the framebuilders section(I have no frame building experience).

Good idea regarding bolting a plate between the stays. Ill try this out temporarily until I can get a flat plate welded between them. There is a decent amount of clearance in the back but not so much in the front.

Thank you for the advice.

Heavier top tube, and beefy rack struts... My Touring bike has 2 3/4" .049" wall 4130 tubes side by side..

they also are the rear triangle .. bent to shape,

I made rack struts for my [Bruce Gordon] Racks of 1/2" steel square tubing..

it sways not at all ..

If starting from scratch maybe ovalized tube wider than it is tall.. and rear rack part of the frame
like Ian Hibell got his touring bikes built , for him..



his first tour bike had a wobbly common 2 strut rear rack
he triangulated it with a tensioned cable.





....

Oval tube. I like it. I could probably get some screw down circle clamps to hold it down till I can weld it down.

The way they used a flat piece of metal to bolt the stays on is just asking for sway. There are hinges designed that way. So it might not take much to improve it a lot. OTOH, most racks will sway some under heavy loads.

I was thinking the same thing. They are very narrow. I have about 20lbs on the top and its like a boat.