Might be a really daft question but I’m looking at new FS frames and stand over wise all are fine as most have dropped tubes.

I notice a lot it says reach, how do I measure that off the bike?

Horizontal distance between centre of top of headtube and vertical line projected up from BB. Spirit level, plumb line, measuring tape and many hands?

Ha. I only have two.

So is. It a natural position? Arched back? Bent knees etc?

Are you thinking in terms of yourself? MTBs aren’t like road bikes – your body position is constantly changing, so you can’t really measure the reach you need, especially as bar and stem have such an effect.

Yea in terms for myself. That’s what I thought so I wondered why manufacturers put reach on if it’s such a variable measure?

Basically reach is how long a bike feels when you’re standing up whilst effective top tube length tells you how long a bike is when you’re sitting down. The higher the stack (vertical distance between BB and top of headtube) the longer the ETT is for a given reach and the slacker the seat angle, the longer the ETT is for a given reach.

Therefore a bike with a slack seat angle and high front end will have a much shorter reach for a given top tube length, which means that if you’re trying to size bikes based on top tube length alone you could end up with one that feels scarily short or too long and unwieldy when descending, even if it feels spot on when sitting and pedalling.

I think it relies on the theory that whatever the seat angle/seat tube shape, your saddle will be in the same position relative to the bottom bracket by virtue of the seat height and layback which are chosen by you but different for each rider.

Find a bike you do like the fit of and compare reach measurements from there.

I was looking at road bikes recently and the difference in reach between the 52 and the 54 was 3mm. I think I’d struggle to notice that.

Find a bike you do like the fit of and compare reach measurements from there.

+1

Reach is difficult to measure without the bike on a jig but is a reliable way of comparing different bikes on paper – it’s the important measurement for how a bike fits when you’re standing up (which is what you’ll be doing when riding anything technical).

My view is that +/- 10 or even 20mm I think you can easily adapt with a stem length (ie a large frame with a 40mm stem could be nigh on identical to a medium with a 50mm stem). Much more than that and handling will start to change.

Seated position is much more important on a road bike isn’t it? So ETT isn’t such a problematic measurement

Brilliant thanks fellas. I’ll match up to the bike I already know fit perfect.

I’ll rest ride the ones I can ASAP.