[Prexus2005]

I'm building my new ASX as a aggressive trail/free ride bike using a 150mm fork up front. The frame is currently set at 7"... but I am wondering if I should reduce it to 6" to match my fork travel?

Is there an advantage of having 6" instead of 7" or why would it have the adjustability if longer travel is better...


Phil.

 

[Nagaredama]

There is a host of reasons why you would use the 6.3 inch mode. The two primary reasons is it slackens the head angle and lowers the bottom bracket. The slacker head angle will add to high speed stabilty and the lower bottom bracket give you a lower center gravity for better turning. The downsides of slack head is a slower turning radius and tougher climbing. Your pedals will have a higher chance of hitting the ground when pedal over/through stuff with the lower bottow bracket setting.

Decide what you like and what you are willing to give and go from there.

Here is the geometry is both settings. The 6 inch mode is listed first.

AS-X Geometry

 

[Circlip]

How did you determine that the geometry numbers listed first are the shorter travel settings? I don't see any indication of that on the chart.

I only ask because your take on it seems counter intuitive. Normally you would expect that designers would want a slacker head angle as the travel increases, not the other way around.

The two primary reasons is it slackens the head angle and lowers the bottom bracket. The slacker head angle will add to high speed stabilty and the lower bottom bracket give you a lower center gravity for better turning. The downsides of slack head is a slower turning radius and tougher climbing. Your pedals will have a higher chance of hitting the ground when pedal over/through stuff with the lower bottow bracket setting.

Decide what you like and what you are willing to give and go from there.

Here is the geometry is both settings. The 6 inch mode is listed first.

AS-X Geometry

 

[Nagaredama]

How did you determine that the geometry numbers listed first are the shorter travel settings? I don't see any indication of that on the chart.

I only ask because your take on it seems counter intuitive. Normally you would expect that designers would want a slacker head angle as the travel increases, not the other way around.

I agree 100%. You would think more travel means slacker but in the case of the AS-X it does not. How do I know? The bottom bracket is over 14.5" high while in 7 inch mode with the Sherman Breakout+ in 170mm mode.

If the BB was 14" and the HA 66 in 7 inch mode the AS-X would be even better. Occasionally you will see a guy running a 24" rear wheel to get those geo numbers in the longer travel setting.

 

[Dogboy]

The geometry info is correct-slacker/lower in the shorter setting. I ran mine in the short setting for a trip to Vancouver/Whistler because I wanted the bike as slack as possible. I really wish it was slacker in the long setting even if they did away with the adjustable travel.

 

[Prexus2005]

Thanks for the info. It makes sense. =) But the geometry tables you linked to, I've seen before. And I thought they are the geometry for the ASX with either 170mm or 150mm forks and not related to the rear travel settings.

So basically, the 6" setting would be good for higher speeds to lower center of gravity while the 7" gets you more manuverability and travel for low speed impacts... right?

Phil.

 

[bonkey]

Thanks for the info. It makes sense. =) But the geometry tables you linked to, I've seen before. And I thought they are the geometry for the ASX with either 170mm or 150mm forks and not related to the rear travel settings.

So basically, the 6" setting would be good for higher speeds to lower center of gravity while the 7" gets you more manuverability and travel for low speed impacts... right?

Phil.

You'll also get a different feel in the rear, because it will take more force to induce high speed compression damping, because your spring rate effectively jumps up, and the leverage ratio drops. I find that I don't particularly like the 6.4" travel setting.

 

[Circlip]

Thanks for the info. It makes sense. =) But the geometry tables you linked to, I've seen before. And I thought they are the geometry for the ASX with either 170mm or 150mm forks and not related to the rear travel settings.

So basically, the 6" setting would be good for higher speeds to lower center of gravity while the 7" gets you more manuverability and travel for low speed impacts... right?

Phil.

I think the geometry tables show 6" mode and 7" mode for both 150mm and 170mm forks. Note the dash between some of the numbers (head angle, BB height, etc.) which I took to mean is the 6" vs. 7", although that's not clearly indicated. So, if the angle is given as X-Y, then the X is the 6" setting, and the Y is the 7" setting.

 

[[email protected]]

I tried mine in the 6" setting.

The BB is lower but under sag the bb was the same height. I measured mine with the same amount of shock sag so all things should be equal.If i remember right i ended going to a 50 lb softer spring in short travel. Since the BB is not actually lower under sag the bike did not really feel any lower to me.Actually because of the rate change the bike felt like it tried to stay up in the travel a little bit more in g outs and corners.

The rate in long travel has a swoopy curve.It falls initially,then has a long mid stroke,then rises late in the travel.This offers a soft feeling throughout most of the travel,being in the long mid stroke it takes sharp hits well at sag and compresses a lot in g outs.

In short travel the bike has a progressive curve that starts soft and ramps hard at the end.I found that a bit past the sag point it ramps hard and keeps it up in the travel.It still takes hits at sag pretty well but did not feel like it sank into corners as well.

On a graph the shorter travel setting looks better to me,rather than a falling-to-rising rate that the long travel setting offers.Riding the bike though,the shorter travel setting has too sharp of a ramp that hurts the ride a little more than i thought it would.

I found that overall i liked the bike in long travel better.in short travel it does pedal a bit better since there is more oil flowing through the shock for the given amount of wheel travel. Due to the highish pivot the pedaling is pretty firm regardless.

The place it works well in short travel is pumping jumps and slalomy type trails since the bike feels tighter and quicker.

I ended up running the 24 in the rear and the geo is really great for a freeride bike IMO.I didn't think the bb needed to be 14.5,and i like the HA 1 degree slacker than how the bike comes. i know a lot of people think the 24 hangs up on bumps but i really don't feel it.Maybe it's the rearward wheelpath of this bike.

Krispy

 

[gurp]

Krispy's right on about the rate change. With an a-c maxed out Super T up front I really wasn't diggin the ASX for DH runs with the rear at 7" due to handling issues (bike felt to tall and short). However at 6" the geometry felt great, but the rate was too progressive early in the shocks stroke. I ordered a 50lb lighter spring, but found when going to swap springs that I need a tool from Yeti to get the pin out (unless I just want to mash it). I also sold my Super T and put on a Z1 Light, and have been playing with both rear travel settings. With 6" in front and 7" in the rear the bike feels OK, but handles alot like a long travel trail bike instead of a DH/Freeride bike. I'm still not completely happy yet. I'm going to ride it more and see if I can come to grips with it. Otherwise I may wind up with a new frame, the Iron Horse 7 Point series looks great, I dig the low BB.

On another note I did think about trying a 7" 888 with a 24 in the rear. How well does your set-up corner compared to more DH specific frames Krispy?

 

[sampo]

I run my ASX in 7'' mode. The forks are 03 Super T's (Soon to be 06 66 SL's). I really like the feel of the bike for DH in 7'' mode, but you do have to be running 35-40% sag. Any less and the BB is too high and the HA too steep. The 5th is designed to be run at 40% sag for DH, and I find that setting really suits the ASX. With a lot of bikes, if you run a true 40% sag you'll be grounding the pedals a lot of the time, but with the ASX this is quite rare.

One thing for people running older (03/04) 5th elements, you must get them tuned to get the low speed rebound circuit sped up (internal) - this will get rid of the 'dead' feeling you experience. Newer 5ths come set up correctly.