Bird Aeris owners thread

Author Message
Posted: Aug 26, 2019 at 1:20 Quote
R-M-R wrote:

Happy to help.

That all sounds reasonable.

This is definitely a case to remove any volume spacers that may be present. The function of spacers, as you may be aware, is to prevent bottoming out for hard-hitting riders who don't want to affect their sagged ride height with more pressure. Since you're not accessing full travel, you want to do the opposite - i.e. remove bottom-out resistance. Here's a good tutorial. It's quite simple, just be careful to not round off the shallow wrench flats on the cap. Some people purchase flat-faced sockets (i.e. without the rounded edge that helps locate the tool) or grind down a normal socket; I use a nicely made adjustable wrench with flat, machined sides and jaws that have nearly zero play. Lots of options, just use care.

If you still aren't using full travel once you've removed all tokens (maybe that's already the case), you can choose to either live with not getting full travel or reduce pressure to use all the travel you paid for, at the cost of lower sagged ride height - which may not be a bad thing, depending on your preferred ride feel.

RockShox doesn't provide compression damping recommendations because there's not much for you to adjust. The top of your right fork leg should have a climb / lockout dial; that's your low-speed compression. You can turn it a little to add support during low shaft-speed events, which may allow you to reduce spring pressure without losing support. This may or may not help your situation; at least it's free to try!

I encourage you to experiment with tire pressure to bridge the gap between small impacts your fork handles poorly and larger hits the fork handles well.

Okay; i’ll certainly experiment with low speed compression. Before having it serviced I do seem to remember a day when it felt particularly good with about 4 clicks of compression; there’s a chance I was running a lower pressure then. Obviously my main concern with reducing pressure is having a fork that dives too often when climbing etc - as with anything in MTB, it’s a compromise.

Add to that the fact the frame is based around 150mm travel fork then keeping the front end up might mean I have to deal with it being a little harsh. I‘m looking into getting a higher rise bar to compensate for the 10mm of lost travel from a rider-position point of view.

What about rebound settings? I find this the hardest thing to feel out, tuning wise.

Posted: Aug 26, 2019 at 10:59 Quote
colourofsound wrote:
Okay; i’ll certainly experiment with low speed compression. Before having it serviced I do seem to remember a day when it felt particularly good with about 4 clicks of compression; there’s a chance I was running a lower pressure then. Obviously my main concern with reducing pressure is having a fork that dives too often when climbing etc - as with anything in MTB, it’s a compromise.

Add to that the fact the frame is based around 150mm travel fork then keeping the front end up might mean I have to deal with it being a little harsh. I‘m looking into getting a higher rise bar to compensate for the 10mm of lost travel from a rider-position point of view.

What about rebound settings? I find this the hardest thing to feel out, tuning wise.

The difference in fork length is at static (uncompressed) length. It bottoms out at the same length as a 150 mm fork, so don't worry too much about it. It's also possible the geometry with the 150 mm fork wasn't perfect for you. Maybe the 140 mm fork suits you better - or maybe not, but it's liberating to move away from thinking "stock" configurations are inherently correct!

There's very little weight on your fork when climbing - think about all the times your front wheel lifts. If anything, it would be ideal to have a fork sit lower on climbs to minimize rearward weight shift. Low-speed compression damping is more useful to stabilize the fork when climbing because it slows the motion, regardless of the weight on the fork.

I agree fork rebound damping is the most difficult to set up perfectly. This also means it's the least important / sensitive, so that's comforting Wink Difficult to say whether this is contributing to what you're experiencing, given what you've described.

When setting rebound speed: if in doubt, speed it up. Too much rebound damping (i.e. too slow) reduces traction, can cause the fork to ride too low, and can cause the fork to not track the ground, which turns the trail into an endless series of tiny drops. Too little damping can cause the fork to rebound before clearing the highest point of an obstacle, which is usually described as the fork "kicking up" at the rider and feeling too lively / rowdy / uncontrolled. I've seen plenty of examples of too much damping, but rarely too little - especially for light riders or anyone using a soft positive spring (don't think you mentioned your weight ... ?).

You might even try the minimum rebound damping setting to learn what it feels like and see if it eliminates some of your problems - and probably causes new ones - then adjust from there. Just be careful about pumping your front wheel through a large depression in the trail, as this could set you up for a lot of rebound energy!

Posted: Aug 26, 2019 at 15:14 Quote
R-M-R wrote:

The difference in fork length is at static (uncompressed) length. It bottoms out at the same length as a 150 mm fork, so don't worry too much about it. It's also possible the geometry with the 150 mm fork wasn't perfect for you. Maybe the 140 mm fork suits you better - or maybe not, but it's liberating to move away from thinking "stock" configurations are inherently correct!

There's very little weight on your fork when climbing - think about all the times your front wheel lifts. If anything, it would be ideal to have a fork sit lower on climbs to minimize rearward weight shift. Low-speed compression damping is more useful to stabilize the fork when climbing because it slows the motion, regardless of the weight on the fork.

I agree fork rebound damping is the most difficult to set up perfectly. This also means it's the least important / sensitive, so that's comforting Wink Difficult to say whether this is contributing to what you're experiencing, given what you've described.

When setting rebound speed: if in doubt, speed it up. Too much rebound damping (i.e. too slow) reduces traction, can cause the fork to ride too low, and can cause the fork to not track the ground, which turns the trail into an endless series of tiny drops. Too little damping can cause the fork to rebound before clearing the highest point of an obstacle, which is usually described as the fork "kicking up" at the rider and feeling too lively / rowdy / uncontrolled. I've seen plenty of examples of too much damping, but rarely too little - especially for light riders or anyone using a soft positive spring (don't think you mentioned your weight ... ?).

You might even try the minimum rebound damping setting to learn what it feels like and see if it eliminates some of your problems - and probably causes new ones - then adjust from there. Just be careful about pumping your front wheel through a large depression in the trail, as this could set you up for a lot of rebound energy!

All good points to think about. I hadn’t really considered that having a little less support when climbing would be beneficial; but of course the closer you are to the ground on a climb the easier it is.

One of the reasons I reduced my fork by 10mm was to improve climbing; I found the bike wandered a little and I had read a number of convincing reasons for having a smaller fork on a hardtail - mainly that it reduces the dynamic changes in geo that hardtails uniquely suffer from versus FS bikes; and this in turn improves handling.

So, when I next get out on the trail i’ll try and remove tokens, quicken up rebound and have a few clicks of compression; i’ll report back!

I’m around 85kg, by the way.

Thanks again!

Posted: Aug 26, 2019 at 16:18 Quote
colourofsound wrote:
All good points to think about. I hadn’t really considered that having a little less support when climbing would be beneficial; but of course the closer you are to the ground on a climb the easier it is.

Marzocchi used to have a lockdown feature, instead of a lockout: the fork was free to compress as usual, then would remain at the point of greatest compression. Instead of locking the low-speed compressing valve, they locked the rebound valve. This worked great for climbing, but was a bit terrifying if you failed to open it when the terrain leveled off.

colourofsound wrote:
One of the reasons I reduced my fork by 10mm was to improve climbing; I found the bike wandered a little and I had read a number of convincing reasons for having a smaller fork on a hardtail - mainly that it reduces the dynamic changes in geo that hardtails uniquely suffer from versus FS bikes; and this in turn improves handling.

So, when I next get out on the trail i’ll try and remove tokens, quicken up rebound and have a few clicks of compression; i’ll report back!

I’m around 85kg, by the way.

Thanks again!

Hope it goes well. Looking forward to the update. Salute

Posted: Aug 27, 2019 at 1:22 Quote
145 -> 145LT -> AM160

Will the same thing happen to the 120 - getting an update?
Mabey ending up with 150/130, greater tire clearance and a wee bit slacker. I guess a TR130 could describe a new smaller Aeris.

Posted: Aug 27, 2019 at 8:11 Quote
Thorjensen wrote:
145 -> 145LT -> AM160

Will the same thing happen to the 120 - getting an update?
Mabey ending up with 150/130, greater tire clearance and a wee bit slacker. I guess a TR130 could describe a new smaller Aeris.

There certainly is a 130 mm × 140 mm × 29" hole in their product line!

Posted: Aug 27, 2019 at 8:57 Quote
HardingTrail wrote:
Thorjensen wrote:
120LT in the Alps

I think that’s the best looking 120 LT I’ve seen.

How did it cope in the alps?

Hopefully getting mine in orange later this week.

Thx. It's a custom build i've did and i'm also super glad how it ended up.

Regarding it handling the Alps. Last year I rode the same trails in Saalbach/Leogang but that was with a non-LT 140/120 susp and running a Deluxe DebonAir RT3 shock. This year running it with the LT linkage and a Super Deluxe DebonAir RCT shock.

The size of the 120LT travel fits my level of riding when it comes to jumps and drops. It rails berms and is so so stabile on tricky natural trails aka Bergstadl trail (black), fast and flowy park trails like Steinberg Line I was laughing the whole 10km down.
It suffers BIG time when it comes to brake bumps and Saalbach/Leogang is brake bump galore. Tho the LT linkage and Super Deluxe shock made the ride way better and didn't get harsh as the Deluxe shock probably due to less heat. So the rear felt fine over brake bumps but my hands suffered quite alot.

Posted: Aug 27, 2019 at 14:51 Quote
Thorjensen wrote:
It suffers BIG time when it comes to brake bumps and Saalbach/Leogang is brake bump galore. Tho the LT linkage and Super Deluxe shock made the ride way better and didn't get harsh as the Deluxe shock probably due to less heat. So the rear felt fine over brake bumps but my hands suffered quite alot.

Only 29ers can fix that issue I reckon! Bring on a short travel 29er Bird Big Grin

Posted: Aug 27, 2019 at 16:48 Quote
colourofsound wrote:
Thorjensen wrote:
It suffers BIG time when it comes to brake bumps [ ... ]

Only 29ers can fix that issue I reckon! Bring on a short travel 29er Bird Big Grin

Less brake squat will help. Birds have a lot of brake squat.

Posted: Aug 27, 2019 at 23:36 Quote
lots of brake-squat and anti-squat. Was Bird trying to play it safe when doing their first longish travel 29er to keep it manageable in terms of pedalling efficiency?

Posted: Aug 28, 2019 at 2:03 Quote
bikefuturist wrote:
lots of brake-squat and anti-squat. Was Bird trying to play it safe when doing their first longish travel 29er to keep it manageable in terms of pedalling efficiency?

They had plenty of experience from past models. The pedaling anti-squat was an evolution from prior designs, the leverage rate progressivity was an attempt to improve on the Aeris 145, and the brake squat appears to be mostly a byproduct of the linkage configuration and the other parameters.

In my opinion, the high pedaling anti-squat is great, the progressivity is great (with a coil shock), and the brake squat is acceptable, though I'd prefer less.

Posted: Aug 28, 2019 at 4:48 Quote
R-M-R wrote:
bikefuturist wrote:
lots of brake-squat and anti-squat. Was Bird trying to play it safe when doing their first longish travel 29er to keep it manageable in terms of pedalling efficiency?

They had plenty of experience from past models. The pedaling anti-squat was an evolution from prior designs, the leverage rate progressivity was an attempt to improve on the Aeris 145, and the brake squat appears to be mostly a byproduct of the linkage configuration and the other parameters.

In my opinion, the high pedaling anti-squat is great, the progressivity is great (with a coil shock), and the brake squat is acceptable, though I'd prefer less.

I accept the way the Aeris handles brake bumps when you get a bike that performs so well on all other aspects.

Posted: Aug 28, 2019 at 6:18 Quote
R-M-R wrote:
Less brake squat will help. Birds have a lot of brake squat.

What’s brake squat? I’ve never heard that term before?

Would this be why it feels unresponsive under braking?

Posted: Aug 28, 2019 at 6:27 Quote
R-M-R wrote:
colourofsound wrote:
Thorjensen wrote:
It suffers BIG time when it comes to brake bumps [ ... ]

Only 29ers can fix that issue I reckon! Bring on a short travel 29er Bird Big Grin

Less brake squat will help. Birds have a lot of brake squat.

Is Brake Squat AKA Anti-rise?

Posted: Aug 28, 2019 at 6:42 Quote
colourofsound wrote:
Is Brake Squat AKA Anti-rise?

Yes. I've never liked the term "anti-rise", especially when using it in the same sentence as "anti-squat".


 
Your subscriptions
no posts

Copyright © 2000 - 2019. Pinkbike.com. All rights reserved.
dv65 0.008126
Mobile Version of Website