Rick Gritters Lowracer recumbent bike Project

Rick Gritters Lowracer & Streamliner Projects

Rick had been racing this new lowracer that he built for for the 2002 racing season quite successfully. If you put it next to an M5, the basic dimensions are quite similar. Differences are that on this bike the cranks don't hit the front tire, and it only weighs 27lbs. Rick calls the Bike the RRR MK 2. (That stands for Ricks Racing Recliner number 2.) 

7/26/2002
The main frame is 1 3/4 x .049 4130. The front boom is 1 5/8 X .049 4130 with 2 layers of 5.7 oz carbon fiber. There is also the same carbon fiber wrap on the down tube of the main frame ... The carbon fiber was added to cover a design flaw: the bike should have been built with larger diameter tubing. Without the carbon fiber the bike was too flexible. It probably still is but the carbon fiber did help. 
The rear chainstays are from a 26" mountain bike front fork with the brake canti pivots moved to the top side and 3/16 thick 4130 dropouts welded in. The chain stays are welded to a 1 5/8" tube, and slide into the main frame tube. (The same as the front boom.) Initially this was to make the bike adjustable in length as well as coming apart for transport, however I couldn't get enough clamping pressure to keep either the front boom or the rear from twisting under load, so I installed a 3/16 aircraft bolt through one side of the joint into a nut plate on the inside. 
This securely locks the joints and still allows it to be taken apart, but I would have to drill more holes to make the bike adjustable. 

Incidentally, the whole bike is welded with an acetylene torch, no brazing.

The chain idler (and I only have one on the power side) is also clamped to the frame in this manner, however, it has a brace from the outside of the bearing up to the seat to keep it from rotating around the main tube under load. It is 3" in diameter. The return chain runs in 2 guides, one next to the idler and one at the front wheel. 

The shifters have just been changed from SRAM twist grips to Shimano bar ends. I was having a lot of difficulty twisting the shifters with sweaty hands, even with gloves on. The bar ends seem much better. The front brake is a short BMX V brake unit and the rear is a standard V brake unit. The brake levers have been relocated to under and centered on the steerer and operated with the thumbs. School's still out on this, as it takes some getting used to and braking doesn't seem quite as good. The bike weighs about 27 pounds; wheel base is 52" total length. From the front of the chainring to the rear of the rear wheel is 84" and the front of the seat without pad is 9 1/2" off the ground.
The main frame is gusseted with .040 4130 sheet at the head tube area and at the junction of the down tube and seat tube. The head tube gusset also incorporates stops that limit how far the front wheel can turn. The main advantage to this is it keeps the tire from pushing on the chain too much. It very much limits turns in tight places, though. 

The front fork is a shortened old steel road bike fork. The head tube is at about a 65 degree angle, which is probably too steep.

The drive train is Ultegra with a 39 and 53 tooth rings and 170mm cranks. The bottom bracket is a Shimano XTR and it is offset slightly to the right with the shims that came with it for chain clearance at the front fork. The rear is 9 speed Ultegra. Note the plastic shim used to enable the use of a small diameter tube for the front derailleur.

The front wheel is a 406 cr18 on a Pantour suspension hub, which works very nicely. The rear is a 559 Mavic X221.

The seat is 5.7 oz carbon fiber over a 1/4" balsa core. It sits on 2 x 4130 brackets that clamp onto the main frame with stainless hose clamps. The lower section of the seat is at about 15 degrees from the ground and the back section is about 38 degrees. It is 9 inches wide and uses a 1 1/2" open cell foam pad.
This 7ft long bike comes apart into small sections for easy transportation. The boom, rear suspension, rear  wheels, seat and chain are easily removable.
It compacts into a nice pile suitable for packing into a trunk, bag, or small aircraft .
3/10/03
Here is the lowracer Rick has been racing for the past year, with a 4" square scaled background. 

These next 4 pictures can be clicked on to view a larger image.

Rick built a 20/20 version of his lowracer for this year. One of his goals for this project was that the bike should be under 2 meters to make it USCF legal. This also allows it to fit in the back of his Ford Ranger with the tailgate closed. It is also lighter and stiffer than the 20/26. So far it hasn't proven to be any faster though he's not finished tweaking yet. 

 

Part of the reason he went to the 20/20 layout is to see what the difference between very similar layouts but different rear wheels would be. Rick built a huge chainring for the 20/20 lowracer to overcome the lower gearing of the smaller wheel.

 

This picture shoes just how similar the two bikes are.

 

Here are the bikes from the front, showing how much bigger the chainring is on the new bike.

Rick will be conducting experiments over the course of the next year to determine what if any difference in performance there is between the two platforms.

3/08/04
Rick sent what he's been working on this winter:
"I've progressed some since this was taken but I've got a ways to go. It's 9'3'' long and 18" wide, all 4130 construction. The cover will be aircraft Dacron. Garrie Hill is going to send me a bubble canopy for the streamliner."

"It's probably more likely super street though. The storm window cover is temporary and as you can see I've already patched up quite a bit."

"I'm still working on some fit and placement issues and the plastic really lends it self to easy changes and patches. So far it seems to be somewhat of a snail. It is pretty light however ( 40#). I've been trying to get a few miles on it also, but the wind is nasty this time of year and I've already figured out that it is pretty scary in the wind. Once I get set up the way I like I'll do the final cover job in aircraft Dacron. total miles to date on it -18." 
3/14/05
Rick got a little testing in on the streamliner recently. He did some tuft testing to be sure that the body wasn't creating any huge vortices, which would slow him down.  He said that the wind was about 90 degree's from the right at about 7 MPH, which may account for some of the tufts hanging down on this side of the 'liner. Rick was running
in the mid 30's in this picture.
11/17/2005
Rick made this trailer to haul stuff around.
Note the wheel fairings. This is a high speed hauler!
2/17/08
Rick modified his FWD bike to use on his Sea to Sea trip next summer by making a new rear frame section that is removable to make it much more transportable. He also raised the back about 2 inches. He is running a Sturmey 8 speed hub and was able to braze a couple cogs on the existing sprocket so now he can have 8 internal and 3 external gears plus a double on the front. Hopefully  he will have enough gears in the mountains. He's still playing with the rear rack and fenders.
See what Rick is up to at his blog  

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