MRP's Ramp Control Pro Cartridge, Carbon Repair Service, & a 13 LB Bike Rack - Sea Otter 2019

Apr 13, 2019 at 22:26
by Mike Levy  
Sea Otter 2019
At just 13lb, the DoveTail rack weighs a fraction of some other options out there.


Short of a tailgate pad on the back of your truck, tray-style hight-mount racks are pretty much the way to go for a lot of us, and most of them are similar. The lightweight DoveTail rack includes a few tricks, though, especially how it attaches to the back of your vehicle. It takes its name from the dovetail joint at the hitch, with the female half being bolted into the receiver. The male half of the joint is on the rack, and you simply slide it down into the hitch and let the weight of the rack (and bike) tighten the joint.

In fact, it gets so snug that the rack comes with a short prybar-style tool that you push through an opening on the opposite side to knock the rack loose.


Sea Otter 2019
Sea Otter 2019
The DoveTail rack attaches to your car via a dovetail joint.


The other notable point is how the rack grabs onto your bike: By the crankarm. A slotted vertical post sits in the middle of the rack, and all you do is put your non-drive-side crank at the 6-o'clock position and lower it down into the post. The pedal fits through a slot, and there's a dial (with a padded head) on the opposite side that you turn down against the crankarm to snug it up. The edges of the slot are padded, too, and there's a C-shaped plastic bushing at the top.

The whole thing is aluminum and is said to weigh just 13lb, which is much lighter than most other racks and no-doubt helped by the fact that each tray only needs to worry about the front wheel. It'll work with bikes up to 48'' long, crankarms between 165 and 180mm (no kids bikes!), and 2.5'' wide front tires. All that costs $395 USD.


Sea Otter 2019
Sea Otter 2019
Your bike is held in place by slotting the crankarm down into a hollow vertical post. A dial on the backside can be tightened to keep it from rattling around.



Sea Otter 2019
MRP's Ramp Control Pro cartridge offers both speed-sensitive and position-sensitive ending-stroke control.


MRP's Ramp Control cartridge works because air is a mixture of gasses that, while extremely thin, will still put up some resistance when forced through an extremely small hole or port at a high rate of speed. Picture it being similar to how oil is forced through ports and shims to provide damping, and if you go back far enough you'll find simple dampers that used air rather than oil.

Adjusting air volume to tune ramp-up usually means changing the physical volume of the air chamber by turning a dial to move a piston up or down, or by adding volume-reducing tokens.

Ramp Control takes a different approach, with an anodized orange knob that adjusts the preload on a small port at the bottom of the cartridge. More preload means more force is required for air to enter the cartridge, supplying you with more bottom-out resistance. Less preload allows air to transfer from the fork's normal air chamber and into the cartridge easier, so you'll have less ramp-up.

The new Ramp Control Pro offers the same speed-sensitive ending-stroke control, but MRP has added threads to the bottom of it that accept their Huck Puck volume-reducing tokens as well, thereby giving it position-sensitive control to boot.
Sea Otter 2019
Thread Huck Pucks onto the bottom of the cartridge to reduce the volume of the air chamber.



Sea Otter 2019
Break your favorite carbon frame? Joe's Carbon Solutions might be able to fix that.


Break your fancy carbon bike that you bought used? Old Faithful manage to hold out until it's a decade out of warranty before cracking a chainstay? Joe's Carbon Solutions can probably help you out. They've been repairing carbon fiber since 1989, long before the stuff was being widely used to manufacture bicycles, and they claim to have saved more than 9,000 over the last thirty years. It's a full-service outfit, too, with re-painting, graphics, and clearcoats all done in-house.

Not every frame can be brought back from the dead, though, and Joe's has a few different methods depending on the type of failure. A broken seatstay might call for a wrap of carbon, whereas an impact hole would require a carbon patch, and some need internal reinforcing before being ridable again.

The obvious question is: What about broken carbon rims. The answer is "maybe," depending on how it failed. A crack at one of the spoke holes needs a patch over it before being re-drilled for the spoke and nipple, but things get a lot more complicated as you get closer to the rim's bead. A nasty rock strike that causes that kind of crack likely isn't fixable.
Sea Otter 2019
A broken seatstay before painting that was repaired by wrapping it in fresh carbon.



47 Comments

  • + 41
 1. No rack under 50 pounds is certified for broduro downcountry shuttles. 2. No adjustment to air volume is needed on coil forks, bottoming out is half the fun!! 3. JB-Weld. That is all.
  • + 7
 Welp...one outta three ain't bad. It's what passes in public school these days....
  • + 3
 coil forks are the bomb dot com, air is dead
  • + 5
 I love the ramp control in my ribbon coil!
  • + 0
 This article just got owned...
  • + 17
 Holy hell the lack of refinement on that bike rack really bugs me.
  • + 13
 The crank mount is horrid.
  • + 0
 @jclnv: I'm sure it's great for the bottom bracket bearings to be beat on in a static position.
  • + 12
 I used a wrap of FiberFix ($8.00 at Home Depot) on a broken chainstay. It was in two pieces. The repair has help up for three years, four XC races and over 800 miles of desert rocks etc. yes...it can be done!
  • + 8
 Step 1: think of problems with current products in the market (bike racks are heavy and big)
Step 2: develop a solution (crank arm holding front wheel tray rack with dove tail mounting solution)
Step 3: determine cost to cover manufacturing solutions and pay your salary ($395 should cover it and plenty of days to ride)
Step 4: Ignore or forget that the market has numerous perfectly suitable bike racks for less than half your product cost including two American made aluminum racks for less than $350 and the vast majority of your potential customers have no interest in messing up their very expensive cranks as evident by your using an very old cheap bike to demonstrate your product.

Dont get me wrong, new innovations are cool, but sometimes you gotta consider price and market saturation for those innovations.
  • + 8
 What the eff did we just read here? Did someone hit the beer garden a little hard?
  • + 3
 At the price of carbon rims nowadays, I‘d always go for Santa Cruz Reverse. They‘ll give you a new one if you manage to break it. No need for a „maybe“.
  • + 1
 True. Happend to me while riding in New Zealand. Although I bought the Reverse wheelset at a local bikeshop in Switzerland, they replaced it in no time down there. Great service from SC.
  • + 2
 Same with the fully Canadian made We Are One carbon rims... great value as well.
  • + 3
 Arlo Englund should make a comeback. I still remember his air carts for various forks.
  • + 2
 The Dovetail rack is cool but I'd still have my bike bungeed and strapped directly to the car lol.
  • + 1
 What fork has an adjustable negative spring and can use the mrp ramp control, and hlr on compression leg.
  • + 3
 A 2017 36 with a Grip2 damper would achieve that.
  • + 1
 @heinous: thanks! The x fusion comes close, but fixed negative coil spring put me off, just needed dvos OTT.
  • + 3
 I'm pretty sure the MRP Ribbon air is all those and comes with ramp control included...
  • + 2
 Fox 36 MRP kit comes with adjustable neg spring. I run it 10% higher than pos and its super plush
  • - 1
 This whole idea of running the neg at higher pressure than the pos baffles me. The fork will only extend until the two are equal. Adding pressure to the neg just reduces your travel. While its true it will effect your mid stroke support (in quite unpredictable ways) but it wont reduce breakaway force at all
  • + 0
 @gabriel-mission9: That is completely wrong. Force is per unit area. The negative spring side has the air rod attached to it, thus less cross sectional surface area than the positive side. Equal pressure creates quite a bit of preload and breakaway force.

However, most air forks use a port on the stanchion (like Rockshox Solo Air), so there is some travel that isn't back by any force. Rockshox dual air was very sensitive and was always better with more air in the negative chamber to reduce spring preload to zero. Manitou's setup acheives the same by simply pulling the fork slightly into its travel with a pump attached- a pump on the valve opens both air chambers at once. It pops right back to full travel after that.
  • + 1
 @gabriel-mission9: My current fork doesn't have a negative air chamber but I've been riding a couple of Magura forks with Flight Control which was some kind of travel adjust that worked by opening the gate between positive and negative air chamber. I liked to open the switch, load the fork slightly and then close it again. This would reduce the travel a couple of mm but what I liked about it is that it was more supple mid stroke and the top out was less harsh. So I could run less rebound damping and the fork could rebound so hard that it would fly beyond the length that I set it to before it would compress again. I felt this got me more grip, especially when cornering rough terrain. I like the rear end of the bike to fly around but I want the front wheel planted. I really liked the way this worked. The last generations of forks with Flight Control worked slightly different because apparently too many customers (and even worse, bike reviewers) found it too hard to unload the front to extend the fork again. I haven't ridden those later forks though. Either way, I do like to have slightly more pressure in the negative chamber than in the positive.
  • + 1
 @gabriel-mission9: in the fox 36 you take a reducer out of the shaft to allow for more stroke. I have a 180mm shaft running at 170mm, which is effectively stock for me. In fact the neg air doesn't start to suck the fork down until about 7% over pressure.
The whole thing makes massive sense for larger riders or big hitting riders who lose small bump sensitivity by using high pressure.
  • + 1
 @R-trailking-S: A solution to that is placing the equalizing port a little further into the travel, such as here forums.mtbr.com/attachments/shocks-suspension/925859d1411494723-debonair-upgrade-kit-img_20140923_114936.jpg with the bulge in the air can. This equalizes the pressures while having a bit more travel left to make for force difference.
  • + 1
 @Pavel-Repak: the evol cans on rear shocks do the same, but I find they sag too much for heavier riders. Went back to LV cans. It's not a function of the volume, it's the location of the equalisation port that causes issues for me
  • + 0
 @R-trailking-S: When the piston moves past the air swap port, the pressures equalise either side of the piston. Are you suggesting that if the swap port is then blocked off, the pressure either side of it will become different, or that the piston will move in one direction or the other? Because thats what it looks like you are saying...

What I'm suggesting is that it shouldn't really be thought of as running more pressure in one chamber than the other. Adding more air to the negative will pull the fork into its travel until (assuming a friction free setup) the forces acting on wither side of the piston equalise. It won't sit there at the same travel as before but with unequal spring pressures. It will compress, which gives you a shorter travel fork with the same travel air spring. This *might* give you a nicer spring curve, depending on the various design specifics of the spring you are running. And the number of tokens you have added, etc. It's not as simple as "adding more negative volume at the expense of overall travel will make your fork better."
  • + 1
 @gabriel-mission9: the force doesn’t equalize with the pressure because the negative spring side has less surface area because the rod takes up some space from the piston. Pressure is a per unit area measurement. That is basic physics. Equal pressure does not produce equal force.
  • + 1
 @R-trailking-S: yes i understand that the surface area differs on either side of the piston. However you havent answered my question....
The pressure equalises through the swap bump. Yet the piston does not magically move if the swap bump is sealed....this doesnt fit with your theory. You have made a mistake somewhere..
  • + 1
 Try considering "pressure difference vs surface area" rather than just "overall pressure vs surface area"
  • + 1
 @gabriel-mission9: The equalizing port means the pressures are the same, but the rod takes up a bit of space, meaning that the force is greater in the positive chamber. If there is no room for the piston to move back, where the pressure would drop in the positive and rise in the negative, the force will be acting as preload. By giving the piston a bit more space to extend, the pressure difference can make up for the difference in surface area, equalizing the forces and providing better bump absorption. ep1.pinkbike.org/p5pb13348170/p5pb13348170.jpg
  • + 1
 again, if this were true the piston would magically move when the swap port was blocked off. Then we could both make millions selling the perpetual motion machine we had just invented. As much as I would love for this to be true, it isn't. So an error has been made somewhere...
  • + 1
 Although it doesn't really matter for the sake of the argument about whether increasing negative pressure does anything to breakaway force. It can't. Whatever equilibrium point the piston likes to sit at, it will re position itself to achieve this when you change the pressure in either spring. It won't magically stay at the forks normal length but with unmatched spring pressures. It will just pull itself into the travel until the forces either side of the piston are equal again. No magic involved.
  • + 1
 @gabriel-mission9: i wasn’t suggesting that. There’s about 3-4 mm of air damped instead os sprung travel because of that port. No preload there, not relevant to those systems.
  • + 2
 @R-trailking-S: That we agree on
  • + 2
 That dovetail thing looks like it would crack after some solid use.
  • + 2
 I suspect that dove tail rack is going to mess up you bb pretty quick.
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