Bike friday has a few 20" wheel bikes , that could be fine on unpaved surfaces

They are made in Oregon in USA, not imported they are the only one made to fit the rider

both size and parts pick . is an individual choice .. so you can get a bike that fits .. You.

rather than getting a bike mass produced, that you adjust to fit tolerably .. which is what you have ...

My Bike Friday Pocket Llama.. will take a 20" - 1.75" wide tire... I can ride it past the ends of a paved road,
But it is not going to plough over larger obstacles like a 29er wheel ..

there is the montague often spoken of here, it's a bigger wheel bike with a frame that folds ,
but again it is a one size frame, so yat may not fit a smaller rider.
a bike is even made for those Shorter than you


https://www.bikefriday.com/folding-b...t-folding-bike

I'd look into this thread, so not all posts there have to be rewritten once more Best Off Road 20" Folder

Maybe one or more of i.e. these threads provide even more info:

Best folding mtb for a short person?

Advice on folding bike for light trails, rails-to-trails, mountain trails

Airnimal rhino am I mad? :)

Will an Airnimal Rhino fit in to a Brompton hard case ?

Airnimal Rhino - anyone ride this one?

Mountainbiking in Colorado on my 2008 Dahon Jetstream XP

Time for a new bike, BF Pocket Llama or Airnimal Rhino, advice please.

Bikefriday Llama vs a conventional MTB?

Airnimal Rhino in the snow with 20" spike tyres

I've done a fair bit of trail riding on a 18" Tyrell Ive.
1.65" tires was the largest I can fit and generally this is ok unless the ground is very loose gravel, or sand/snow.
Roots, rock gardens and wash board surfaces will be a major problem as its hard for the small wheels to roll over them.

A 20" bike will certainly be better, but I'd say not by much (and don't expect miracles vs even 26" rigid mtbs with >1.85" tires. (wrt trail riding)
The Dahon Jetsteam is the main one to consider for a 20" wheeled folder.

The problem with larger wheeled offerings is that they are all biggish even after the folding and more clunky to handle folded.


I did end up selling my Tyrell Ive in favor of getting a 650b folding gravel bike.

Montague has 3 frame sizes.

Frame Sizes

If going Montague, should pick the ones with lockout on the suspension fork, for all the road\flat\gravel.

I was going to suggest trying a pair of Schwalbe big apples on your uno.

I find my Mu Uno is perfectly acceptable on dirt. Not crazy about any folder on gravel. But then I also ride a 16" wheel bike most of the time so the 20" feel really cushy, lol. Plus, I'm very old school and my mtn bike experience of posting out of the saddle works wonders. The more important drawback to the Uno is the single speed when constantly going up and down hills.

OK ( re # 7) bike friday has 8 all reach differences , the seat and handlebar masts are additional sizing customizations..






....

the best story of someone whose keen to discover how much a folder would hold in true offroad, is Debcar Blog!
this guy made 50 epic trails in usa with a dahon jestream 20"!

its truly epic story...also brakeages and diy fixes

DEBCAR Story

I second this, use it everywhere.

My mountain bike riding was done in the days when bikes were rigid, no shocks at all. A 20" could be used off road but I can't imagine it would be a lot of fun. Something you can do for a bit and tolerate, but definitely not something you would want to do regularly. It's all about the right tool for the job. If you're going to ride rutted rocky places, get a bike specifically to make that a pleasure, not just bearable. Just like I wouldn't want to use a mountain bike for multi-modal, lol.

BMX is off road on 20" wheels , Motos are massed starts , just like the motor bikes..

2 Olympics have now had a BMX medal race series ..

(though those tracks were groomed for equal conditions for all races)




...