Steering effort BOP MPS vs. GSE?

[Turboflash]

Asking question/opinions: for those that have had both BOP MPS and GSE Power steering on same (or nearly identical) sled, how would you compare the steering effort for each? Nearly same? Or, which one was easier at average trail speed? Which one is easier on tight twisty trails?

 

[STAIN]

One of the benefits of EPS that no one really speaks of is the fact that it takes the "shock" out of the bars.
A wrong landing, railroad crossing, or frozen rut is far less likely to jam your wrist/thumb .
Have you ever driven a truck or wheeler with manual steering and get the wheel jerked out of your hands?

 

[earthling]

The MPS would have the same benefit (less shock transferred) as it has a mechanical advantage over the leverage of the skis vs unaided steering geometry. Probably not as much effect as EPS but then it depends on speed as EPS is not engaged at moderate to high speed.

 

[sideshowBob]

My biggest concern with MPS would be the loss of ski travel with the resulting reduction of turn radius. I had a steering effort reduction pivot on one of my Vmax 4s and it definitely reduced the sleds turn radius.

 

[RobX-1]

The nice thing with Travis' MPS is that there are three holes or settings to adjust the steering effort. I'll concur with sideshowBob in that the hole for max reduced steering effort also equated to a reduction in turning radius. I found a happy medium with the lowest setting in that it provides adequate steering assist while also maintaining a decent turning radius. When I first purchased my 18 Apex with EPS, I could immediately tell the difference when getting back on the 08 Apex. Now, with the MPS, not so much. I do, however, still feel the 'trail chatter' or what Stain refers to as the "shock out the bars" when compared to my EPS but not as bad as it was when running without the MPS.

 

[turbogts22]

When turning the bars on an EPS sled the electric assist motor has to spin up (under power) in one direction or the other providing assist. A sudden hit at a ski also tries to spin up the motor but the mass of the motors rotating component helps to slow down this transition. It acts kinda like a shock absorber in this instant. The MPS won't have this dampening effect.

 

[1nc 2000]

A steering dampner would reduce unwanted feed back into the bars.

 

[earthling]

With any steering assist system there is a translation of effort at the bars through the steering mechanism to the skis. That translation comes by way of force multiplier (steering assist) whether mechanically or electronically induced and the fact that the assist in a manual steering system like the MPS comes by way of an increase in leverage from the perspective of the bars means that there is the exact opposite action in the reverse, the skis have less leverage over the bars, and that is true at any speed. If the mechanical advantage is 1.5:1 (example) then the reverse is true, any ski induced feedback will be inversely and proportionately less. Is it damping... not really but I am not sure what is happening with the servomotor in the cat EPS is damping either. What matters is you will feel the impact less with MPS than without it.

Assuming the cat EPS is based on a servomotor design and just looking at the external design it appears to be, the Cat EPS system has magnets holding the servomotor in any given position. Because the design of the EPS is meant to allow trail feedback through the bars (otherwise you would have dead steering) those magnets cannot have holding power that would impede trail 'feel'. As an example, when you are running down the trail, hit a bump that effects ski direction, that quickly comes back to the bars as 'feel' of the trail but the fact that you are holding the bars into the corner will mean that any available assist at that time will allow you to react with less effort. Is that damping.. only insomuch as the magnets offer minor initial resistance to a change in direction.

Regardless of whether it is a servomotor or traditional motor, to me the biggest advantages of EPS is speed moderated assist without any loss of turning radius. EPS is better than MPS, but how much better, and if you do not have an option and are trying to retrofit to an older sled then either MPS or GSE will be some form of improvement over stock with of course, but with different compromises (MPS = less turning radius, GSE is not speed moderated and quite a bit more expensive than MPS).

 

[marathon mike]

I have had all 3 now. While BOP serves well for some it’s no where near as good as the power options. My biggest issue was the lack of turning radius when set for the easiest setting. The GSE is great option if you aren't prepared to buy a new sled. Offers easy steering that is one level so might be a bit harder at lower speed so that it’s not to easy at high speed compared to the new factory sleds. I know it’s a chuck of change but do it right the first time and you will enjoy your limited winter rides.