Brompton rider size

[Sergeant Pluck]

On a Brompton that has the extended seatpost, what’s the smallest size of person (or inside leg length, even better) that would be comfortable with that seatpost as far down as permissible?

[rogerzilla]

It's likely to fit adults of the smallest stature, unless they have a form of dwarfism.  Miss Z the elder certainly rode mine when she was about 13.  If you really want a saddle height measurement with the post almost scraping the floor, I can do it.  The advantage of the standard (i.e. no longer standard!) post was smaller folded size and lighter weight, not an ability to fit shorter people.

[Sergeant Pluck]

Thanks. Since my post I discovered this, and as you say the differences in the various posts affect only the max height.
https://brompton.zendesk.com/hc/en-us/articles/360010454177-What-is-the-maximum-minimum-rider-height-

I think we are going to be OK. Extended post needed for me (1.86m) but, as above, that doesn’t affect the minimum height as I had previously thought it might. The less tall rider of this purely hypothetical Brompton is 1.53m, well within the stated range.

What’s the crank length on a Brompton?

[PaulF]

Think they’re 170mm, but I can check in the morning.

[Sergeant Pluck]

A Brompton has arrived and with the extended post it accommodates both of us very well.

I am now going through a Brompton self-initiation. Expect stupid questions. Albeit fewer than in days of yore, as now every question has already been asked and I can JFGI and probably see a video specifically addressing my arcane query.

[Sergeant Pluck]

Rode the Brompton to work today for the first time. It was... OK.

How do taller people find the stock forward saddle position on a Brompton?

I am 1.86m and I felt it necessary to reverse the Pentaclip and get the saddle back. Even then, unless I consciously avoid it, I find myself perched on the back edge of the saddle. That would usually make me think "saddle to low" but it's at the right height.

[LittleWheelsandBig]

Saddle back is better for riding. Saddle forward is better for folding small.

Small bar ends also help get enough distance between handlebar and saddle.

[Sergeant Pluck]

Saddle forward is better for folding small.

Thank you - makes sense. I’m not too bothered about folding small - I have an extended seat post anyway.

Next question. Tyre pressures on the standard Marathons - LBS recommended 100 and 110 psi f/r to minimise the risk of pinch flats. That’s bone-shaking. Do they really need to be that hard?

[LittleWheelsandBig]

I run 20-30 psi lower at both ends but tend to watch the road surface and ‘ride light’ over defects. If you do neither, stick with boneshaking pressures.

[Sergeant Pluck]

Thanks again.

Being hemmed in by traffic for much of the time, sometimes rough stuff is unavoidable.

I noted today that there is a lot of squirming if forced to go along edges of yellow lines etc., another thing I haven’t had to look out for when on Schwable Big Apples, so I might cautiously experiment with pressures to see if it reduces that.

[LittleWheelsandBig]

Run 20-30 lower on the front but keep the rear pressure up - that is a good compromise for most.

[Kim]

I run 20-30 psi lower at both ends but tend to watch the road surface and ‘ride light’ over defects. If you do neither, stick with boneshaking pressures.

Similarly, I usually inflate to 90 on the front and 100 on the back, and leave it a while before topping up.

Depending on the wheel-removal faff factor of your chosen gearing, it may be prudent to keep things bone-shaking on the rear.

Bromptons are allergic to potholes regardless of the tyre pressure