I thought I would post this up since I have been struggling to get the rear suspension setup on my bike. It took me a while to really understand what the designers were trying to achieve and now that I have my head wrapped around it I thought it would make an interesting discussion.
I have been struggling with getting good feel out of the rear end since I got it a few weeks ago. The bike is definitely fast and I have been setting PR's going up and top 10's going down, but it didn't feel good while doing it. As always I turned to the fantastic Linkage Design blog found here;
Linkage Design
If you ever want to really understand what is going on with any suspension design this is one of the best resources around.
Now looking at the leverage curve of the Nomad 3 it is different than almost everything out there right now. It has a rising/flat/falling leverage ratio that made no sense to me at first. Here is a picture of the leverage ratio
You can see that it almost parallels the Nomad 1 and SC seems to have gone backwards here. Looking at it from the opposite angle here is the force required to move the rear wheel at each point in the travel;
For the casual rider these leverage curves make no sense when using an air shock because when taken in tandem with an air spring curve the end stroke is going to be exaggerated. The force required to move the rear wheel will go up exponentially since an air spring also has a rising force as the shock is compressed and when coupled with the falling leverage ratio it makes the end stroke VERY stiff.
Now what I did not think about is what the bike is designed for. The Nomad is really a pure race bike and makes no design compromises for the weekend warrior. It is made to win races at the EWS period. In that scenario nobody really cares about climbing prowess or plush suspension, they only care about the clock during the timed stages. For a comparison, when I raced the EWS Colorado this year I just about killed myself on my first run. My suspension was setup WAY too soft and I was bottoming out everywhere. I had to raise my fork pressure by 30% plus add two tokens. In the rear I also had to significantly up my pressure. Now this setup is almost unrideable when cruising, but at race pace it felt perfect.
For comparison the Mach 6 has a leverage ratio and force curve that are completely inverted when compared to the Nomad. When paired with an air shock the result is an almost linear force line. To get the bike setup for a race you need to eliminate all of the small bump compliance to keep it from bottoming. The Nomad is exactly the opposite. You can set it up supple in the beginning of the stroke and it will still resist bottoming very, very well. Again the combination of a falling leverage ratio with a rising spring rate means reaching the end of the curve will be difficult no matter what your pressure setup. The Debonair helps alleviate this with the extra air volume smoothing out the spring curve, but a coil should be a very good match for this bike.
For comparison, here is the leverage ratio of the Nomad 3 overlayed with the Bronson.
As you can see the Bronson is a fairly linear ratio with a rising rate at the end. This will allow full travel without a significant hit since the leverage will help overcome the rising spring rate from an air shock. If you were to try an use a coil in this situation it would blow through the end of the travel.
This is all armchair engineering, but I think I am pretty close. I am interested to hear others thoughts on this so let me know what you think.
I have been struggling with getting good feel out of the rear end since I got it a few weeks ago. The bike is definitely fast and I have been setting PR's going up and top 10's going down, but it didn't feel good while doing it. As always I turned to the fantastic Linkage Design blog found here;
Linkage Design
If you ever want to really understand what is going on with any suspension design this is one of the best resources around.
Now looking at the leverage curve of the Nomad 3 it is different than almost everything out there right now. It has a rising/flat/falling leverage ratio that made no sense to me at first. Here is a picture of the leverage ratio
You can see that it almost parallels the Nomad 1 and SC seems to have gone backwards here. Looking at it from the opposite angle here is the force required to move the rear wheel at each point in the travel;
For the casual rider these leverage curves make no sense when using an air shock because when taken in tandem with an air spring curve the end stroke is going to be exaggerated. The force required to move the rear wheel will go up exponentially since an air spring also has a rising force as the shock is compressed and when coupled with the falling leverage ratio it makes the end stroke VERY stiff.
Now what I did not think about is what the bike is designed for. The Nomad is really a pure race bike and makes no design compromises for the weekend warrior. It is made to win races at the EWS period. In that scenario nobody really cares about climbing prowess or plush suspension, they only care about the clock during the timed stages. For a comparison, when I raced the EWS Colorado this year I just about killed myself on my first run. My suspension was setup WAY too soft and I was bottoming out everywhere. I had to raise my fork pressure by 30% plus add two tokens. In the rear I also had to significantly up my pressure. Now this setup is almost unrideable when cruising, but at race pace it felt perfect.
For comparison the Mach 6 has a leverage ratio and force curve that are completely inverted when compared to the Nomad. When paired with an air shock the result is an almost linear force line. To get the bike setup for a race you need to eliminate all of the small bump compliance to keep it from bottoming. The Nomad is exactly the opposite. You can set it up supple in the beginning of the stroke and it will still resist bottoming very, very well. Again the combination of a falling leverage ratio with a rising spring rate means reaching the end of the curve will be difficult no matter what your pressure setup. The Debonair helps alleviate this with the extra air volume smoothing out the spring curve, but a coil should be a very good match for this bike.
For comparison, here is the leverage ratio of the Nomad 3 overlayed with the Bronson.
As you can see the Bronson is a fairly linear ratio with a rising rate at the end. This will allow full travel without a significant hit since the leverage will help overcome the rising spring rate from an air shock. If you were to try an use a coil in this situation it would blow through the end of the travel.
This is all armchair engineering, but I think I am pretty close. I am interested to hear others thoughts on this so let me know what you think.
