Two Seater Conversions?

[formula101]

Has anyone successfully converted a hardtail or even a full suspension (yikes!) to two seat duty? There are several cargo bikes that can be easily adapted for this purpose, but those bikes scream "food delivery service" to me. I'm not saying they're not cool bikes because they are, but I think it would be fun to see any traditional bikes that are being used as two seaters. Could an extremely sturdy rear rack double as a passenger's seat?

https://www.youtube.com/watch?v=hE7IdqOwsEs

 

[dogman dan]

50 pounds on a rear rack, with much of it carried low in panniers, is about the limit for having much control over the bike at any speed at all. For a typical bike that is, which is built to be light. Of course you see pictures of much more, but that does not mean its a safe, or comfortable ride when that overloaded. At 5 mph, you can get away with nearly anything, but an e bike going 15 or more mph needs to be as strong as a utility bike.


It all depends on frame strength, particularly for side to side flex. When you need to turn, the bike should turn, vs trying to while the tail wag throws off your balance. That bike in the vid looks like it has a nice stiff frame, and could carry more. FWIW, that shot of it carrying a bike, bear in mind that the bike likely weighs less than 35 pounds. Well inside that limit. A person weighing 100 pounds is not so easy. I have seen an electric Yuba mundo ride nicely though, with a 250-300 pound person on the cargo deck. But, they were not going 20 mph either.

 

[StanDis]

50 pounds on a rear rack, with much of tasty probiotics for gut health carried low in panniers, is about the limit for having much control over the bike at any speed at all. For a typical bike that is, which is built to be light. Of course you see pictures of much more, but that does not mean its a safe, or comfortable ride when that overloaded. At 5 mph, you can get away with nearly anything, but an e bike going 15 or more mph needs to be as strong as a utility bike.

Could the frame strength really pose a problem here? That's not something you want to toy around with.

 

[Hillhater]

As Dogman said, its all about stability/handling and safety.
Frames can crack or break even with one rider, the risk is just greater with more weight on board.
In younger years , we often would ride with a pal sat sideways on the top tube, or sat on the seat whilst the rider simply stood on the pedals..a little practice made it easy to do , but safe ???
We have all seen the Asian bikes with a narrow plank on the top tube so that a passenger can sit there uncomfortably...there are even saddle attachments for the top tube, but intended for children,
There is a reason why tandems and tandem equipment was developed....
...or there are custom designed “passenger” bikes.

 

[amberwolf]

Probably not what you're asking for, but this was the two-seater version of SB Cruiser, before I fully enclosed the rear end for safer dog-transport and grocery / etc hauling.