A question on drag/aerodynamics of various rear mounted h2o cage systems. I recently replaced my Profile rear mount Aqua Rack system with a Minuroa system. THe Minuroa system, for all intents and purposes, lookes like an inverted U. Off the rack cages are mounted to the inverted U, which is clamped to the seat rails
THe Minuroa system seems to hang awfully low behind the seat , leading to my question on drag/turbulence of one vs the other. Not sure if the differences in the two systems really add up to anything significant, but any knowledge or insight would be greatly appreciated.
THe Minuroa system seems to hang awfully low behind the seat , leading to my question on drag/turbulence of one vs the other. Not sure if the differences in the two systems really add up to anything significant, but any knowledge or insight would be greatly appreciated.
Thanks for any help
From my limited knowledge (and not just about this ) that is precisely where you want it. Right behind your seat. Those XLab things which are behind the seat are big walls behind your ass creating big pockets of air turbulance. The lower behind the seat you can get it the better since the air coming off your back will flow over it instead of hitting it straight on. And any air hitting your seat post will allow it to flow around the cages.
Markus is correct. Last weekend, I did a test on a 65 kph descent, and put one hand behind me just in front of the Xlab waterbottle holder (which sits high). I could not believe how much wind was coming off my back and hitting the waterbottle which sat as a pylon slowing me down. On Wed, I did the same descent without the water botttle and could feel the bike actually pulling through past 65 kph (perhaps it was in my head), hitting a max speed of 68.5. Sure the weather and wind patterns could make a difference, but in general this is a very sheltered descent. In any event, put your hand up behind you where the bottles would be and you’ll see what I mean. Better to have them right behind your legs.
I recently switched from the Profile Aqua to the Minuroa for a few reasons: First, the Rack didn’t fit my Dual’s seatpost, second, you can’t position a saddle pack anywhere useful while using it, and third, the reclining position of the rack made it more likely to launch your bottles.
Using the Minuroa, I can fit a small/medium pack behind the seatpost, tucked nicely between the rack and the post. It does look a little suspect, with the low-riding position, but you can put on the Profile Design bottle cage and mount them in the highest position. I only wish they would have angled the bottle mounts slightly outward to allow storage of tires/tubes etc. between them.
I’ve had them all over the past 15 years, Minuroa, Profile, Xlab Saddlewing and Flatwing, that plastic thingy…Tracx or whatever it was, and a few others. Take this for whats its worth…just my 2 cents…I like the Flatwing the best. I’ve thrown all the others away or sold them.
The minuroa was too low, profile was shitty made, Tracx broke in one ride, Saddlewing weighs a ton, some didn’t fit, etc…
the Flatwing fits my bike well and keeps the bottles in the gages…no launches. I use one bottle and strap the spare tubbie and stuff to the other side.
Now…remember…I ride Zipp 2001’s and the aerodynamics of no seat stays and seat tube changes everything. With long legs I want the air flowing right thru the legs and out the back…no low bottles hanging there to get in the way.
The other day I was swimming, and I was changing from one side of the pool to the other so I could more easily see the pace clock. I Put on my paddles, pull buoy, and I had tot put my water bottle between my legs for a 25. It was amazing how much I could feel the drag from the water bottle! I know water is more viscous than air; however resistance due to air at 25mph has to be similar to resistance in a pool at 3mph (or at least it gives an idea). Hide that bottle!
The salesman at my local bike shop told me there was a Minoura Twin cage that mounts high above the seat similar to the Saddle Wing in addition to the one that mounts low. I bought it, and it’s great so far but does not showing up on Minoura’s website- I don’t know if it is new. Also, I can still fit a good sized saddle bag underneath with the seat all the way forward. Hope this helps.
I took some pics of the boys at Epicman descending the Keene Hill at LP at 70+kph. Try descending in a pack, managing a turn, one hand on the aero bars, the other holding a camera and having your whole world seen through 1 sq cm :-).
All kidding aside, I have a friend who films xc ski videos and puts on masters XC ski camps. They did a few really cool shots on a high speed descent in Mt Washington area (British Columbia). What you don’t realize is that the cameraman is actually going down the descent and he is on XC skis at > 60 kph, until suddenly you see his ski tips at the bottom of the shot. You’d swear the cameraman is on a snowmobile or something, but he is actually on skinny skis, looking through the camera.
This has nothing to do with aerodynamics but I have had two of the Minuroa rear racks fail on me. The bolt that clamps the plate above the rails of the saddle just sheared off leaving the cage hanging at an awkward angle. Once it happened at the end of a five hour ride when my bottles were empty and the other time right in the middle of a five hour ride when my bottles were close to full. This latter forced me to use anything and everything to tape/tie the cage back to the saddle so I could continue on. I would suggest you replace the bolts with longer ones and use nuts to secure them rather than using the threaded holes in the plate. I now have two of these plates with bolt sheared off and firmly embedded in the threaded holes.
If you get you Minoura through Endurosport, they actually send you lock nuts with the package to do just as you say (great sales and delivery service too). I have never had the 1st proplem. See: http://www.endurosport.com/
Oh, so that’s the “retrofit” their catalogue refers to. It’s too late-I bought the Profile one. Works well but no room for a bag for spares etc so C02 cartridges and the spare get taped to the seat post which I’m sure causes all kinds of drag.
) that is precisely where you want it. Right behind your seat. Those XLab things which are behind the seat are big walls behind your ass creating big pockets of air turbulance. The lower behind the seat you can get it the better since the air coming off your back will flow over it instead of hitting it straight on. And any air hitting your seat post will allow it to flow around the cages.