[Closed] Reach or effective top tube?

Depends on your stem length, bar width and backsweep, back length and hip hinge flexibility - and how short the reach on your current bike is. 2.5" is about the difference in reach between a small and a large.

I have realised over the years that it is rather hard to get an accurate "feel" of how a bike will just looking at geometry charts.

Case in point, I recently took a test ride on a large Orange Crush (the new model) which has an ETT of something crazy like 650mm. On paper it looks massive, but the cockpit felt more compact than my current 26er Specialized Camber due to the shorter stem and higher cockpit.

By all means, use the geometry charts to pick out some frames that might fit the style of ride you are looking for, but test riding is a must.

I know you can't beat a test ride but some of the stuff I'm looking at is really hard to throw a leg over.

Couple of bikes are similar to what I had before but the transition and bird aeris are a departure from what I'm used to.

I've gone from a bike with 575 ett and 396 reach to 620 ett and 449 reach. Big difference, but losing 30mm off the stem and 20-25mm by going to an inline post means the saddle to bars distance is pretty much unchanged but the extra 25mm in effective reach (inc stem) when standing feel much better, more centered and with more room to move around.

I did try a few of these longer modern geometry bikes, and in different sizes to get an idea of what suited best. Looking at the numbers is only half the story, but it conjunction with demo/test rides can help narrow the list down.

Edit: If you're looking at an Aeris, that's what I went to from an Anthem.

Might this help: https://geometrygeeks.bike/ ?

Yeah, inspired by Ben's contributions on here, I've added the new 145 to the list.

Onzadog I saw on the Pootle thread that you where looking at Transitions, if you're struggling to get a ride on one and you're after a large, you're quite welcome to a sit on my Scout.

I'm in Northish Leicester and ride in the Peak/Cannock on a reasonably regular basis.

Fathomer, thanks for that. I might well take you up on that. Tried a medium on the pootle so now I know I need a large.

Stevied, useful site that. Gives me three of the five I'm looking at.

I'm going through a similar process. As I live abroad there are a few bikes (Bird, Canyon etc) that I just can't justify buying on spec from geometry charts. As a result I'm restricting myself to bikes I can test ride here. Luckily I found a Transition dealer down the road so I'm just waiting for my trails to thaw out..

I've bought frames mail order after checking and measuring things but that's because the financial outlay is lower and no one really does small indy frame builders like the British..

Any thoughts from the evening crowd?

Not a fan of the ETT so tend to totally disregard it to be honest.

Reach, stack, HA & ST angle are the important numbers for me. I went from a Reign to a Patrol which on paper were very similar, save for the steeper SA on the Patrol, which made it easier to pedal. Annoyingly (IMO) other than that, the Reign was the better bike, but hey, it's easy to look back.

My new bike sits somewhere between the 2 previous in terms of geometry.

To match my current ett, the reach will be about 2.5" longer. How noticeable would that be?

I reckon it'll be really noticeable for the first hour, then just feel totally fine.

I'm so glad reach has become one of the standard measurements, I can now tell from geo charts whether a bike will fit me or not. Hasn't let me down yet anyway.

TBH ETT is almost completely useless, it just doesn't measure things it needs to.

Reach is pretty limited, but that means it's actually measuring something, which is more useful.

Is ETT really that useless? My saddle is usual the same height as the stem so it gives me a good idea of the distance between my hands and my arse. That's useful for all the time I'm not standing up, so whenever I'm climbing or traversing.

I agree, once I've stood up, ETT is pointless and then the reach is more use.

The problem with ETT is that most full-sus bikes don't have a seat tube that runs in a straight line from the bottom bracket - it's either offset, bent, angled or some combination of the three. ETT is based on where the seat post crosses a horizontal line to the top centre of the head tube but it's very unlikely that that's your saddle height. And if it's your saddle height on one bike, it won't be on another that has a different stack height.

So if you get two bikes that are identical apart from one having a taller head tube (and thus stack height) then that one will have a longer ETT, even if the reach is the same. If they're identical but one has a slacker actual seat angle but the same effective seat angle, then the reach, stack and ETT will be the same - but the one with the slacker seat angle will feel longer when you're sitting on it, especially if you have long legs.

And that's just the problem with ETT when you're sitting down - stand up and it is completely irrelevant!

That's half of the problem with offset seat tubes. The other half is that the quoted seat tube angle is also not going to mean much. Most manufacturers appear to quote the actual angle of the tube (judging by the numbers, they often don't indicate how it is measured). They could do a bit better I feel, like drawing a line from the BB to the same point they measure horizontal top tube to.

Actually, effective top tube is really useful for such cases as if you combine it with reach and stack (and some trig) you could work out the "effective seat angle".

ETA not chainstay length

And that's just the problem with ETT when you're sitting down - stand up and it is completely irrelevant!

I demo'd a Large Aeris 145 a couple of weeks ago: it's got a 655mm ETT and 506mm reach, yet thanks to the inline post and 35mm stem the saddle to bars was only 15mm longer than my Medium Pitch which has a 586mm ETT and 446mm reach.

I tend to just measure horizontally from front of saddle to centre of steerer bolt and base my fit around that. Seems to work for me, but I may have the concept all wrong 🙂

Iainc, its not that bad an idea. I found that on a number of my bikes, without even trying, they were within half an inch when measured from saddle to bar.

It's not just geometry, I've been pouring over kinematic charts as well. Buying new bikes is so much hard work.