MRP's Boost Solution and New Ramp Control Cartridge - Interbike 2017
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Today's suspension forks work pretty darn well out of the box, and you can't really go wrong if you're spending the big bucks on a high-end fork from one of the main players. That fact pretty much killed off the aftermarket fork hop-up business many years ago, but there are still a few upgrades that make sense, one of them being MRP's pint-sized Ramp Control Cartridge.
We've shown you this thing before, and I've even reviewed one back in February, but MRP keeps adding versions to fit more and more forks - the one pictured here is their latest, and it goes inside of any X-Fusion fork with 34mm stanchions.
When it comes to adjusting ramp-up and bottom-out resistance, you're likely picturing either tokens or some sort of system where the volume of the air chamber is altered by turning a dial to move a piston up or down. And, with an orange knob on top of the cartridge, it sure looks like that's what's going on with the Ramp Control Cartridge. But that's not how it works. Instead, the orange knob adjusts the preload on a small air port at the bottom of the cartridge. Adding preload means that it requires more force for air to enter the cartridge, and that means more bottom-out resistance. Less preload lets air transfer from the fork's normal air chamber and into the cartridge easier, so you'll have less ramp-up.
There are no volume-adjusting tokens involved, and the Ramp Control unit creates speed-sensitive control as opposed to position-sensitive as tokens do.
The move to Boost spacing was a real pain in the ass for a lot of riders, and especially those who own expensive wheelsets that they'd prefer to move to their next bike, or if they wanted to buy a new fork but it was only available with Boost axle sizing. And those riders are 100% right to bitch about Boost - yes, there are some clearance advantages at the back of the bike, but there's essentially zero perceptible difference in rigidity between a non-Boost and a Boost fork. So, what's a person to do?
MRP's Better Boost Adapters might be the answer, but only if you have a DT Swiss, Industry Nine, or Stan's front hub (a Hope version is coming soon). The kit includes two anodized orange hub end caps that replace the stock caps, and a spacer that moves the rotor out from the hub shell. Longer rotor bolts are also included. Unlike some kits, MRP's end caps are captured and won't fall out when you take your wheel off, and you won't need to re-dish the wheel, either.
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With all the bitching people seem to forget that axles in particular haven't been too standard. We've had Curnutt with a 30mm axle, Specialized used a 25 for their dedicated USD forks for their Enduro frame, then I think B1 used a 165mm rear axle even in their 4X fully. It is just that at some point we got some pretty big OEM players, SRAM in particular. So their choices have become pretty prominent and determine what others do (though 100x15 was from Fox. onepointfive from Manitou and even Syntace is more influential than some might think). But it seems things are stirring up again. Other brands are stepping up and more high end bikes are being equipped with X-Fusion, Suntour and Manitou is back too. Maybe even RST at some point.
So yeah SRAM has been pretty wild with standards lately but it is pretty easy to ignore them nowadays (and still ride an up to date bike).
when we point this out an people say "well no one's forcing you to buy it"
an we don't buy it....
an ultimatley LBS an small parts cpmpanies suffer
but hey Ebikes eh?..................
Three days later, Yeti announce the new SB6 for the same price.... It was brutal
I went boost front end just so I could have the Cane Creek Helm to match my Double Barrel CS Coil rear end..... but I'm not buying into any more gimmicks
I don't think it is all about forced upgrades though. Syntace for instance has been very considerate. They came with 142x12 to give you the same convenience in the rear as we already were used to in the front. And they did it in a way that allowed for many hub brands to just swap the end caps and your hubs were up to date again. Same with their EVO6 take on the boost spacing. Boost was already there, they just made it more useful. Something similar could be said about 110x20 (the original). Really it really took different end caps to squeeze the same hub in a 100mm wide fork the flange spacing and bearing spacing wasn't optimally utilized and the extra width of the original 110x20 hub was pointless.
www.wolftoothcomponents.com/products/boostinator
Yeeah... Not quite.
that's not a good thing. yeah, it saves some time, but if given the opportunity to make your wheel stronger, why pass that up?
thats why the wolftooth/lindarets boost adapter is superior. you DO need to redish your wheel, meaning you'll have a stronger wheel as the drive side spoke angle gets less extreme
@Muckal obviously we've all survived this long before boost, but there is absolutely nothing wrong with an even stronger wheel. i really wish more rim makers would go asym for even better spoke angles. the WTB asym is the stiffest non-carbon wheel i've ever ridden
I speak only the truth. Now if your CK hubs are USED... it might be a different story.
Talked to CK about it, they want me to buy an $80 axle and re-dish the wheel 5mm. So basically just buy a new hub, that's what i heard.
I'm having a 10mm spacer made for the drive side and will just have the wheel dished
Pinkbike, Jan 9, 2013"
www.youtube.com/watch?v=Tw-sAUSmkfk
You can change the volume of ramp control by turning the dail. the cartridge can occupy more or less space inside the air chamber and hence change the spring characteristic in exactly the same way spacers would but without the need to disassemble your fork every time you want to change or try a different setup.
dampening is basically how much of the impact energy is converted into friction (heat by pushing oil through valves)
A spring by itself would basically kick back with the same force the trail pushes into it hence you would bounce around like on a pogo stick. by changing the rate or the characteristics you can change how much force is needed to push it for a certain distance.
Dampening means to absorb the impact energy (or correct transform kinetic energy into heat) which means it when the spring is compressed there is less energy stored in it and it will not kick back like a pogo stick or a trampoline and your ride will feel smoother...
lets take an example (i am using easy numbers for my sanity). using the ramp control, it is my understanding that the first 2 inches of your travel would be firmer off of a 6 foot drop vs a 3 foot drrop. without the ramp control and using volume spacers instead, the first two inches of travel should feel roughly the same of the two different height drops.
this is just how i am reading the article. but it sounds like your entire stroke would get firmer off larger drops with the ramp control installed, not just the end stroke.
Basically it's compression damping on the flow of air into the Ramp Control Cartridge.
There *IS* some damping going on, however since it's a compressible fluid (air) instead of an incompressible fluid (oil) the characteristics will be quite different from any oil damper. I'm not sure if it would feel anything like "damping" as you think of it on a normal fork. With oil, fork travel always corresponds to a proportional amount of oil volume flow, because in an incompressible fluid pressure buildup is instant. With the MRP system, pressure builds up in the main chamber first, then leaks into the cartridge at a rate determined by your adjustment - so damping effects would be delayed and small, which is part of the reason we use bladders to keep air *out* of our dampers. This would almost be like changing the amount of air in your spring throughout the course of the compression, but it's hard to describe because it's not just a function of position, but time/speed as well. In practice *I think* this would result in a harder initial hit but more linear response overall, compared to volume tokens which are progressive. Again, I don't think the damping effect would be that noticeable, mainly because air is a shitty damping fluid. I think you'd mainly notice what it was doing to air pressure in the main chamber, but the two are related.
On the rebound stroke air would flow back into the main chamber, but since rebounds are generally way slower than compressions I'm not sure you'd notice any difference on rebound. The exact point at which the pressure would equalize would depend on your adjustment and the speed of the impact. If it's wide open it's basically equalized the whole time, if it's mostly closed off it may not equalize until the rebound stroke.
@WAKIdesigns it also allows you to ride across water!
Yes its not exactly the same as spacers.
I am not 100% sure how it exactly works even though i have one installed on my own lyrik. I did not open it up.
Reading the description my best guess is that the piston or slider inside the cartridge is not completely sealed (or having a tiny hole) which would result in air pressure behind it being the same as in front of it. if you have a have a high speed impact the air would have to travel behind that piston which will only happen with a delay hence the effect on high speed would be comparable to the effect of spacers. In a way this is very similar with oil getting pressed through a hole in a dampening cartridge however because of oil being a thickish fluid a lot of energy is used for achieving this displacement where as a gas can travel through the valves with much easier and will provide no significant energy loss or dampening.
on the other side If you press very slowly air pressure behind the piston can equalize through the small hole in time so you will not feel a difference to a regular fork without spacers.
you are right on the stroke. because s smaller volume air spring is more progressive the beginning of the stroke would not change much when you drop. towards the end of the stoke the spring becomes harder and harder which should keep you from bottoming out without sacrificing sensitivity in the beginning like simple higher air pressure (or preloading) would do
In my mind this would be the only way it would make sense to construct a cartridge like this. A closed chamber behind this piston would mean that you by reducing volume (making the fork more progressive) you would also raise the pressure inside the spring chamber which would make the spring harder but that's not is not the case.
The other good reason for assuming the cartridge is built like that is that it's fairly cheap and manufacturing a completely sealed piston like the air spring itself would be more complicated and therefore more expensive...
maybe @NoahColorado can chime in on the mechanism?
This is sort of correct. It's almost like if your token volume changed with the size (speed) of the compression. The damping of the airflow is what changes the "virtual" volume, but it will feel like different spring pressure, rather than like compression damping with oil.
FWIW, the PB article reviewing the cartridge has a pretty helpful graph and explanation.
Maybe you don't feel like your require a stiffer wheel? Do you? / have you change to boost and actually noticed?
I know that some World Cup DH racers uses low tension wheels, that's right - a deliberate reduction in wheel stiffness by the fastest guys in the business, but the industry still thinks us normal guys need stiffer wheels.....
I can't remember the last time I thought boy the front wheel is flexy.....or folded a wheel.
Edit: Noah beat me.