Bird Aeris Owners

Probably been asked before but here goes.

Going to order an Aeris frame but undecided on size. I’m 5’11” with logish arms and would usually go for an 18″-19″ frame, which would put me on a large, but I’m a little concerned about the 640mm ETT length on the large.

How do other owners find them?

Cheers

I was also worried about the length, until I test rode it.
The 35mm stem really does bring it back.
FYI I’m 5’10” with slightly short arms and love the M.

Have you talked to Dave/Ben? I guess you are probably as ‘in-between’ sizes as you’re likely to get, but I’d probably still put you on the L mainly because you say 18-19″, whereas I would have always been 17″.

Where are you based? You can demo them down south from Bird HQ or Swinley. Also Pedalabikeaway at FoD demo them.

Longer TT and reach is partly reduced by the 35mm stem (if you run one)

I used to ride 18/19″ frames at 6’3 (always a tad too small) and am on an XL aeris.

I’m enjoying the extra room and the bike actually fits me for once!

Based North Worcestershire. With work and family getting a demo would be difficult.

I think I’ll email them and ask a few dumb questions.

Other opionions gratefully received.

I’m 6’2″ and demoing a L and XL on saturday, so will report back if it helps.

I had similar thoughts recently regarding Aeris sizing, and ummed and ahhed a lot!

I am 178cm (5’10”), with an inside leg of 32”, and arms perhaps slightly longer than average for my height. For my old bike, a Whyte T130, which had a 609mm top tube (no idea on reach sorry) and 55mm stem, that was about right. Medium with its 594mm toptube and 1132 wheelbase was too small. For most ‘’traditional’’ geo bikes, at 5’10” – 5’11” you are generally probably better off on a Large. This is particularly the case for the ‘’smaller’’ brands such as Santa Cruz.

On the Aeris, I went in with the same sort of attitude. I test rode both the medium and the large, both with a 35mm stem. On first test ride (while both felt great) I felt that the Large was perhaps a better fit, as it was that bit more roomy and stable, especially when riding around the car park. However, I certainly wouldn’t want to be any more stretched. i.e. I was at the limit, even with the 35mm stem, and I wouldn’t want to run a shorter stem like that for general trail riding.

Still undecided, I had another test ride, and after this further time on the bikes, I actually decided that Medium was better. It was still stable and roomy (thanks to its 1187mm wheelbase and 448 reach) but was just that bit more nimble and playful through twisty sections, whereas on the large I tended to run wide a bit more on corners. In addition, while I could just about run a 150mm dropper post on the large, it would be at the limit really, so the medium gives the opportunity to really slam the saddle if and when required! Likewise, the standover on the medium is that bit better too.

Ultimately, I could ride either size (and there really isn’t much in it to be honest). If I was only riding flat out, open tracks at v high speeds, trying to get air at every opportunity, the Large would probably be better. For more twisty trails, the medium would be better. For general, all round trail centres, bike park Wales and everything in between, the medium seemed to be the better overall fit. I therefore went for a medium, albeit with a 40mm stem (but could have run a 35mm stem). And as above, it is still long for a medium!

Other things of note – Olly Forster of Bikeradar rides a medium Giant Reign and believes it is a good fit. It’s pretty identical in terms of top tube, reach and wheelbase to the aeris, and he rode a large Kona Process previously. Likewise, Tomas Kuptys, a Bird rider, rides a Large aeris, but he (appears) to be around 6’3”.

When I spoke to Bird in more detail about this, they said that generally people around 5’10” go for a medium.

I may have confused you further, but hope it helps!

Sounds like I’m right in between sizes.

Contacted Bird and they usually recommend a large for someone my size (just under 6 foot).

Think I’ll probably go with that. They have the large in my fav colour too, blue.

Yes, I am that shallow.

I think large will be best for you… my son has a large with 35mm stem (he’s 14, 5’10 and still growing) He loves it… it could be a shade too big for him now, but it six months it will be bob on… so for you should be perfect.

Yes, if I was 5’11+ like you, I’d have gone large too. And you’ll be able to run a 35mm stem nicely. At 5’10” I was even more in between sizes, which is a bit frustrating, but at the end of the day, either size would work well just in slightly different ways.

Thanks for the advice guys.

Large will be ordered.

If it helps – I am 5’10 (bit long bodied, short legged though) and ride a large Aeris. I really don’t feel stretched out on it. Rides great.

Oh yes… went for the blue too!

Yes that helps. Cheers Hotfly

Blues fastest! I’m 5’8″ and fit just right on a medium. There’s only about 25mm of the reverb lower protruding from the seat tube, so it wouldn’t fit anyone much shorter.
(Of course, being taller, this won’t affect you)

Another quick question, what’s the seatpost diameter on the Areis? I’m assuming it’s 31.6 as it’s a 34.9 clamp?

Cheers

Pants! Will only be demoing a large now, as the xl hasn’t come back from a bike mag.

^^^^^^^^

That’s arse.

Sorry Coole, we were promised its return this week 🙁

On sizing, most people at 5 10 tend to gravitate towards the M, as its a good size medium running a 35/40mm stem. The sizing is close enough that a L with 30mm stem is the same in all but wheelbase and seat tube than a M running a 50mm stem. That does make it a little trickier to pick but also offers choice. Personally I ride a M most of the time, and reserve the L for days at places like BPW where Im going to have berms to support the cornering, and really just want something to charge through the rocks. The L for me is noticeably harder work in more normal trail conditions as the extra effort needed to keep the weight forward to stop the front wheel from going straight through in every corner does get a bit tiring after a while! Its also effected by bar choice too, I prefer something around the 780 which makes a M feel much like a L with say a 750 bar, but with more weight over the front tyre for improved grip, even if its at the cost of outright straight line speed.

No worries Ben, still looking forward to trying the large

Seat post diameter anyone??? Can’t find it on the site.

I was all set to order a large but you’ve got me wondering again now Ben 😐

31.6

Full information here

Ha, thanks Ben.

How did the demo on the large go Coole? What were your thoughts?