Bird Zero Sizing/Spec Help Please

JayX2A

Hoping you good people can help!

My brother wants to get a Bird Zero after he rode our mates older version.

So hoping to get some advice and ideas on spec and size from owners and riders.

Firsty size, same as me which is - 5ft 11 with inside leg of 32". Looking at Bird it says the large - but the effective Top Tube seems quite long on the large at 650mm. Top Tube on his Mantra Pro is 625mm and any longer would be too long I think.

Budget is tight so please see below specs and advise if anything is really bad! (dropper to be added at later date).

TR10
Xfusion Street Fork
E1900 Spline Wheels
SLX 2x10
SLX Brakes
High Roller 2 tyres
Aeffect riser and stem
Raceface Turbine Seat Post
Chainstay Protector

£1188 total or £1258 with XT cranks

Or the same as above but with Sram GX 1x11 for £1153, but think he would prefer to stick with 2x10

Sram is out of stock but 2x10 set up avaliable.

Any feedback on size and spec would be greatly appreciated!

poah

don't look at the ETT measurement - thats only relevent for when you are sitting. have a look at the reach length

JayX2A

POAH wrote:

don't look at the ETT measurement - thats only relevent for when you are sitting. have a look at the reach length

Ahh thanks,

Mantra 19" - 442mm
Zero Large - 472mm
Zero Medium - 447mm

cooldad

They are designed to be long. So large could well be right. I'd give them a call with your dimensions and ask the question.

The Rookie

To the ETT you need to add 20mm if either has an offset seat post - so that moves the Mantra (offset seatpost) to 645 versus the Zero 650 (not offset) - seems pretty much the same size now!

JayX2A

Interstingly myself and my brothe rboth sent emails to Bird and one came back saying medium and the other large!

Stem on the Saracen is 70mm so by no means short!

Herdwick

TT length + stem length = overall sadle to bars length
So if you have a 625 tt and 80 stem = 705 overall
If you have a 650 tt and 40 stem = 690 overall, so the bars are effectivly closer to the rider, not as long as you might think. reach mainly affects descending giving you a more streached out pos thus better balance and control.
Also all other equall longer reach gives better climbing position but some times if combined with low stack not so comfy on long rides

Herdwick

As rookie mentioned add seat post offset to the equation and you will get the idea

BloggingFit

Depends on the model too.

The TR is longer and takes up to a 130mm fork

The AM is shorter and takes up to a 150mm fork

You could be a large in one and medium in another.

JayX2A

AM might be a bit overkill for him, I think. It's just red routes and bridle paths over south downs.

The guy at Bird did say that the medium was already quite roomy in the TR.

The Rookie

You need to consider bars and stem together, wider bars means a shorter stem gives the same effective reach due to the way you reach out to the grips.

JayX2A

The Rookie wrote:

You need to consider bars and stem together, wider bars means a shorter stem gives the same effective reach due to the way you reach out to the grips.

Ahh so much to consider and me and my bro are so useless at this lol!

The Rookie

Lol, you need to take a metaphorical step back and and look at things logically.

If the Mantra is the right size then the Large seems right based on the info you've given, length is similar to headtube and the shorter stem on the Bird makes the cockpit shorter but that will be somewhat offset by the wider bars.

Herdwick

get the large and be done with it, you won't regret it!!!

JayX2A

Yes, we looked at figures yesterday!

But, going off that its been mentioned it adds 20mm to the Mantra:

19" Mantra - 625 + 70 Stem + 20 seat post = 715mm
19" Bird - 650 + 50 Stem - 700mm (or they do a 40mm stem so 690mm)
17" Bird - 625 + 50 - 675mm

Can someone explain seat post offset to a newbie as both the saracen and bird seem to have angled seat posts? I know its something simple that I am missing!

cooldad

All? bikes have an angled seatpots - the seat tube is at an angle.

Offset means where the saddle clamp is in relation to the seatpost.

If you look at the Bird, the clamp for the saddle is directly in line with the seast post, the Saracen is slightly offset to the rear.

It just puts the saddle a little bit further back. Thats the only reason. You can swap seatposts depending on where you want the saddle to be, the same as changing stem length and rise, or bar width and rise. Or crank lengths.

They all just put the contact points where you want them

JayX2A

cooldad wrote:

All? bikes have an angled seatpots - the seat tube is at an angle.

Offset means where the saddle clamp is in relation to the seatpost.

If you look at the Bird, the clamp for the saddle is directly in line with the seast post, the Saracen is slightly offset to the rear.

It just puts the saddle a little bit further back. Thats the only reason. You can swap seatposts depending on where you want the saddle to be, the same as changing stem length and rise, or bar width and rise. Or crank lengths.

They all just put the contact points where you want them

Thanks you for the explanation - that makes a lot of sense!

We also looked in to the AM - but thats out of stock until September!

BloggingFit

My Aeris is pretty much identical in reach to the TR. I'm 5'9 and run a medium with a 35mm stem and 750mm bar which I find good for me. I'm more longer legged than torso so based on that you could get away with a large using a 35mm stem.

JayX2A

Sent Bird an email with more info on my fit, so hopefully go from there!

JayX2A

So after a long chat with Ben from Bird we are going with a Medium and 50mm stem.

Next decision is 1x11 or 2x10 for 2 unfit overweight riders who are getting their butts in gear!!

Plus grey or blue...

Herdwick

Get fit then.