27.5 frame sizing

[ishaw]

Thinking of buying one, but unsure of how to size it. Measured my 26ers and they all have varying c2c measurements, the largest being 20 inch c2c, and quite a comfy ride with a fair bit of seat post (I'm just shy of 6ft).

As 27.5 wheels are bigger, should I be looking at a smaller frame, or will a 20 inch c2c be fine?

My 29er is 18.5 c2c and also a comfy ride, having done a number of 3 hour rides without complaining physically.

I've found one at good price, but online and frame only so can't try before I buy. Its size description is xl, which none of my frames are, but the c2c is equivalent of my L designated 26ers.

 

[mattr]

Exactly the same sizing. It's only the wheels that are bigger. A medium is a medium and a large is a large..... Same with 29er.
Even the bottom bracket heights are broadly the same.

They may be some changes in how the bike is designed to be set up (seat tube angle, head tube angle etc) but the basic sizing will be similar/same.

 

[ishaw]

Re:

That's the problem. It's an XL, but c2c is the same as a couple of my L 26ers. Hmmmm

 

[mattr]

Well, yeah, you start actually measuring the bloody frames, you're going to get into all sort of issues!!

And TBH, i'd be more interested in stack and reach than C2C, top tube and frame size, especially going from retro to modern.

 

[mattr]

Out of interest, what's the 29er and whats the 27.5?
Might be worth getting the geometry charts up next to each other and having a look.

 

[ishaw]

Re:

29er is a cube, the 27.5 is unbranded, suspect made in china but thought I'd have a stab as I bought a lot of 27.5 specific stuff for a build then found a crack in the frame.

 

[mattr]

Doesn't really help without geo charts.
But the trend at the moment seems to be shorter seat tubes and longer reach so despite it being very slightly taller, it might be a metric shit load longer.

 

[brocklanders023]

Re:

As above really, if you usually go large with 26” go large with 650b. Also as mentioned the other measurements are more important such as stack, reach, effective top tube and head tube from my experience. It’s even worse now as frames are getting shorter in the seat tube to accommodate long dropper posts! :facepalm:

 

[ishaw]

Re:

Cheers for the feedback. I'm trying to get more detail. The frame looks a little unconventional, but not too strange/long. It has an odd top tube though, curves downwards to join the seat tube which will impact standover height.

Hopefully with more measurements I can work out sizing/fit. Due to being retro I'm used to a smaller frame, more seat post and long stem, so aiming for comfort now I'm getting older and creakier.

 

[drcarlos]

I have a 29er Cube and dropped a frame size to account for the wheels and also as they don't do an 18" frame in the 29er, only in the 650b. I have ridden their 650b too though as my brother has one and it's the 18" frame, it fits me fine in height but feels too short in the top tube.
It's odd as my 29er is about right in both height and length and I wouldn't want to go to a 19" frame as I'd lose the standover height.
I will probably look for an 18" when I get a 650b FS, which probably won't be a Cube unless I get a discount on a Stereo 120.

Carl.