Building a Recumbent Weight Weenie Stick Bike Highracer
Carbon High Racer
Construction and Evolution

By Warren Beauchamp

This is my dual 700C weight weenie practical recumbent bike project. Over the years I obtained weight weenie parts, but didn't had an appropriate bike to put them all onto. In 2009 I conceptualized and built a lightweight stick bike highracer (Bacchetta clone) but I quickly learned that type of bike doesn't work well for tall people.

In 2010 the bike was cut up and rebuilt as a 20 lb Z framed highracer bike. This version of the bike worked great for riding on roads and paved trails, was fast on flat roads and climbed respectably due to it's low weight. I put thousands of miles on this bike over 10 years of riding it.  

Now it's 2021. The world has changed, I'm 11 years older. I no longer have bike trails near where I live and don't feel safe out on the country roads due to the increase in distracted drivers. I now live closer to gravel roads so the bike is being reincarnated as a Dual 26" FWD Gravel Bike to be better on gravel and rough chip seal roads.
 

2009 - CF Stickbike

In this project I used a straight carbon main tube, and bonded it to the carbon rear chain stays shown below.

Initial Parts
* 24" front wheel with CF aero fork
* CF Easton "K2" rear chain stays
* XL CF VK seat
* CF cranks and lightweight BB
* CF twist shifters & rear derailleur
* Lightweight Paul brake handles.
* Aluminum BB shell

Need to buy:
* Caliper brakes
* lightweight chain
* head set
* handlebars?

5/01/09
I now have the main CF tube and CF head tube. The main tube is a little thinner than I would like, so I'm going wrap the tube in in Kevlar and CF to beef it up. After I join the main tube to the rear stays I may cover the whole thing with a pretty sleeve. This will also cover my joining job and the chain stays to give the bike frame it a uniform appearance. Soller also sells some large heat shrink tubing, which I may use in lieu of a vacuum bag to squish the sleeve/epoxy onto the CF main tube. Also the heat shrink tape from Aircraft Spruce would help to provide more pressure.
6/08/09
Mark Anderson notes: "Where as aircraft spruce only sells one kind of shrink tape, My new favorite composite supply shop is www.decomp.com They sell the best shrink tape around, the Dunstone Hi-shrink tape, in several different widths and some with release coating. Very helpful over the phone. Simply crushing power when shrunk, I don't have a way to measure it but dang, it's strong stuff. And it releases like butter."
9/13/09
I notched the CF tube, and put the tube and the K2 rear stays in the frame jig.

 
Mark had sent me some super-lightweight two-part filler putty, which I used to join the main tube to the rear stays. It's cool stuff. It starts out kind of powdery but ends up doughy after kneading it for a while. After this cures, I'll trim the leading edge of the seat stays until they look right, and then start covering the mess with CF.

I decided not to use the 24" front fork and wheel, opting instead for two wheels the same size.

11/14/09
Before arriving at the final frame geometry and starting the cutting, I needed to figure out what wheels and fork I would use. I want this bike to have the same riding position as the NoCom, which has a 9" seat to BB height differential, to make the transition painless. This means I may have to cut the main tube a angle the boom tube down a bit.

After much contemplation, I purchased a set of Mavic Aksium 700C wheels from Ebay for $200. Not the lightest wheels at a weigh of 870g front and 985g rear (1855g per pair), but a lighter set would have been the big bucks, and these had good reviews.

After losing a couple Ebay bids for Easton C90 CF forks, which were nice and light weight, and matched the rear triangle (also made by Easton), I bought this 335g no-name CF fork from China. It was about $90 with shipping.
11/21/09
I drew up the bike to scale. Specs:
wheelbase: 48"
trail: ~3"
Seat angle: 25 degrees
Headtube: 90 to main tube.

I bought some CF tubes from Mark to use for the handlebars.

Mark also notes that the Elan team uses peel ply tape to wrap their bike frames. The tape can be wrapped tightly to compress the layup, and the excess epoxy weeps through the material. After curing the tape is removed. This sounds like the perfect solution to me, plus it's cheap, which is a good thing. It's available at Aircraft Spruce.
11/22/09
This weekend I CFed the rear stays to the main tube using the "cover in plastic wrap and smash together with foam" method. Here several layers of CF were wetted out with epoxy and then covered in plastic wrap. With the clear plastic over the layup it is easy to press the layup into the frame and squeegee out any bubbles.
I then added a chunk of dense foam and wrapped it tightly. The foam presses the layup into the part and fills the voids. Here, the frame keeps warm on my old hot-water furnace to help it cure quickly.

Next, the main tube will be reinforced with 1 layer of Kevlar tube, and then a layer of CF fabric. This will be wetted out and then wrapped with the peel ply tape noted above.

11/25/09
Meanwhile, several days later, the part is all cured. I sanded off the excess epoxy that was pressed out the sides of the plastic wrap. Also the wrinkles in the plastic leave fine epoxy ridges that needed to be sanded off. Both the top and bottom look good, and all the CF was pressed tightly into the part.

A note on sanding CF - Because CF dust is not good to breath, be sure to wear a quality particulate filter mask and do the sanding outside of your living area.

I need to make the inside diameter of the CF head tube a bit smaller to fit the 1 1/8" headset. This means I need to form a layup of CF to the inside of the head tube. I hacked up a inner tube to use as a bladder to push a layer of CF tightly and evenly against the inside. A standard 1 1/8" head tube has an ID of 33.8mm. This tube has an ID of 38.7mm. It needs to be 4.9mm smaller ID. The CF I have is about .05mm thick, so that means I need another 5 layers on the inside.
11/29/09
I rough sanded the main tube to allow good bonding, then slid on the Kevlar sleeve. I spiral wound some thin Kevlar thread around the sleeve to hold it in place for wetting out. The single layer of CF has been cut. Mark A. is sending the peel-ply tape, so hopefully next weekend I can do the final layup on the main tube.

The Kevlar and CF will overlap the rear stay area to provide a strong transition. This will be a high stress area.

12/02/2009
I received the fork from China. It looks good and is very light. Also ordered the headset and some other small parts from icyclesusa.com. Mark is sending some peel ply tape.

12/06/09
I reinforced the main tube with a layer of Kevlar and a layer of CF, and wrapped it up with the peel ply tape. It worked great. With the peel ply tape I could tell where the layup was not quite wetted out enough and then add a bit more resin. The excess resin went right through the tape. I peeled the peel ply off before the resin fully cured at it came off pretty easily. Some strings from the peel ply tape were still embedded in the layup as the edges of the peel ply tape frayed a lot during application, but I should be able to remove them with a little time.

I also used the bladder I made a couple weeks ago to add CF to the inside of one end of the head tube. I had problems with the hacked inner tube bladder leaking during the last two pressure tests. The 3rd time was the charm. To ensure the bladder could expand properly, I cut the CF into 4 sections. I also cut the plastic wrap which protected the bladder into many sections to allow expansion.

I had ordered two CF tubes from Hong Kong for the seat stays. They were advertised on EBay as wing spars for a model airplane. I thought they were big enough diameter to be used for seat stays but I did not convert the metric diameter to English properly because they were too thin. I think they may work nicely as cable guides/stops.

Fortunately I was dragged to several thrift stores, one of which had some golf clubs with CF shafts. I picked up two of them as they were only $1.30 each, such a deal. After hacking them up, it looks like they will make great seat stays.
12/12/09
After removing the peel ply tape, I cut the holes for the head tube and BB with my hole cutter. Well, it wasn't quite that simple. First I measured everything a couple times, then I checked to be sure things were square and level a couple times, then once again before cutting the holes. Don't worry about how this looks now, I will need to cut some of this off and add more CF to make the front of the main tube strong and pretty and aero.

Using a bubble level works great, as you can measure in multiple paces and gravity always points straight down!

I test fit the head tube and BB in the frame and put the frame in my jig. Looks straight, just like a stick!
Also I laid up a CF tube over a waxed aluminum tube, which will be used over the steerer tube to attach the handlebars. I sure hope that the "freeze the cured part and the aluminum tube pops out" trick works. I have been scared to try it in the past.

The picture shows the wetted out CF rolled over the tube before I wrapped it in peel ply tape.

I chopped some leftover CF into small bits and mixed it with some CF to fill in around the head tube and BB. I'll sand it and cover it with a couple layers of CF later to strengthen it and make it pretty.

The frame weighs now weighs about 3 lbs.

There are a huge number of little brackets and things still to make. I am trying to make as much out of CF as possible. I have been buying parts and am trying to find ones that are light, but not too expensive. There seems to be a sweet spot for parts that are lighter than average, but not much more expensive than average. It will be interesting to see what this weighs when I'm done.
12/14/09
I pressed in the headset cups with my trusty vice, using some old gloves for padding, and added the fork and wheels. The cranks are just sort of hanging there in this photo. After eyeballing it from several angles, everything looks straight and true, yay!
Experiment 792a: Success!
After removing the peel ply tape, I took the CF covered aluminum tube outside and packed it with some scientifically calibrated low temperature material. Common name "snow". I heard some pops and clicks as the tube separated from the CF. At 30 degrees F, the tube didn't just fall right out, I had to persuade it with a rusty bolt of the correct diameter. I was however able to remove it without any cursing or ritual bloodletting.

12/15/09 - I laid up two CF parts to be used to mount the seat base.

12/27/09
Last week I bonded the two seat base bracket parts together with lightweight filler. This week I reinforced the connection between the parts with several layers of CF. 

The bracket will be clamped to the boom with some hose clamps. Yeah sorry, going low tech there. The seat will be bolted to the bracket to allow some minor adjustment.

Here's the XL velokraft seat balanced on the frame to check out the seat angle and seat to BB height. I hung a stick as my 25 degree reference, as that's the NoCom seat angle. I was shooting for an 8" seat base to BB height difference to match the NoCom, but ended up with 10". I could cut the boom tube and angle it down a few degrees to fix that. Maybe next year...

Next I have to make the rear seat stay brackets. They will be held on with titanium bolts.

01/01/10
Here are the top seat stay brackets. It's all held together with JB Weld for now so I can confirm that it's straight. I'll cover all the brackets with another layer of CF to strengthen them and make it prettier, then do a bunch more sanding to blend it all together. It's hard to make small CF parts, but they are nice and light.

 
1/05/10
Titanium goodness.

These 5mm, 6mm, and 8mm bolts will attach the seat, clamp the handlebars to the steerer tube, and skewer the main tube to the idler.

1/17/10
Here are the upper seat stays after adding some CF to strengthen them. Gee looks kind of like the picture above, huh. Don't worry, it will look pretty after I sand it and cover it with a coat of epoxy.

You can see the cool Paul Moto-Lite brakes in the background. These allowed me to use the 26" wheel canti-studs with the 700C wheel.

Another exciting bike building picture. I epoxied the CF tabs to the CF golf club shafts and then clamped then to the rear seat stays. After they cured, I cover the mess with more CF to strengthen them. 
The seat is now fully mounted and seems sturdy. I'm ordering some titanium hose clamps from McMaster Carr to replace these steel ones.

This picture shows the bike clamped to the bench press to drill the hole for the idler.

CF tubes are never the right diameter, so you have to make some yourself. Today I made a tube to mount the idler bolt, and another that will allow me to use bar-end shifters. I also mounted the handlebar stem to the headtube clamp tube. Handlebars can't be far off!

This weekend was 'Winter Bike', a big swap meet where all the Chicago area bike stores try to sell off their used or unwanted parts and bikes. I picked up a nice light Bontrager front brake and a bunch of other parts. Cool!

I weighed the bike with wheels, seat, brakes, BB, cranks, derailleurs, chain, idler and anything else I could find piled on top , and it weighed 18 lbs. Excellent. The only significant items I didn't weigh were cables and seat pad, so there is still a chance that this thing will weigh in at under 20 lbs when it's done! The Bacchetta Carbon Aero II weighs 21lbs 6oz, so I now have a benchmark to try to beat!

1/26/2010
Here are the handlebars ready to be glued together. The bar-end shifter mounting tubes turned out great.  The long tiller is a bit flexy, so as seen above, I'm thinking about adding a thin CF tube to reinforce it.

I had my LBS run a tap through the aluminum BB shell, but it's still very tight. I hope the BB does not get stuck.

I CF'ed in the idler bolt tube and mounted the huge Terracycle idler.

Here's the stick bike with the drivetrain more or less completed, and the tiller handlebar stem. This bike should have an extremely efficient drivetrain.
1/31/2010
I attached the handlebars to the stem. Here I am in "the position". The bike doesn't look so big with me on it.
No custom bike build is complete without problems.

Problem 1 - Recumbent bikes have a front brake problem because the front brake cable interferes with the frame tube when you turn the wheel to the left. The solution? Make the cable exit the bottom of the brake. Here I'm jigging up a cable braze-on abd a bolt that crews in where the brake's cable clamp would normally be.
Here's the brake with the new cable stop installed, and the cable clamped on top.

Problem 2 - I'm using a road brake in front and the brake in back has road brake cable travel as well, so I can't use the Paul brake levers. I'll go get some cheap Performance levers with adjustable cable pull and cut them up for the center mounted aero brakes.

Problem 3 - I can only thread the rear derailleur cable from the back of the bike, so I need a fancy Rohloff cable joiner.

 

Problem 4 - I'm using a SRAM ESP 9.0 rear derailleur, and Shimano bar end shifter, which are not exactly compatible. The Shimano shifter pulls enough cable to get through 6 or 7 of the 9 gears. Current plan is to file enough off the shifter body to allow the shift lever to move far enough to access those extra gear.

It seems like I'm constantly cutting up perfectly good bike components to make them work with recumbent bikes. I have several sets of cranks and a set of pedals with bits cut off to provide streamliner clearance. I have a couple sets of brakes I cut up that are not much use now. I have cut up a bunch of brake levers to make them aero, or make them fit tubes they weren't designed for.

The stick bike was designed to be as close to the NoCom position as possible so that I'm using the same muscles on both bikes. Here's Warren on the NoCom hacked out of a NoCom picture and pasted onto the stickbike picture. Are the positions the same? Pretty close. The seat and handlebar are the same, but the stickbike's BB is about an inch higher.
2/15/10
I made  good progress over the past couple weekends. I cut up and mounted the Forte levers, and they have the right amount of pull. I also added a bunch of cable stops. You can see here that I ran the bare cables right out of the brake levers, to cable stops on the stem.
Here's the bike with the completed handlebars. I have since moved the chain tube chunk to the front fork, where it can float up and down, but will protect the fork and still reduce chain flop.
To make the cable stops first I cut a chunk of CF tube about 3/4" long. This is tubing I bought via e-bay that I thought would be useable for chain stays but was way too thin for that. It's the perfect ID for sliding in a cable end though, or using for a cable housing guide. 
 Next, I rough up a cable end with some 100 grit sandpaper. This increases the surface area and gives the bond more surface area to stick to .
Then I cover the cable end in JB weld and slide it in.

There have been some concerns that the cable stop will eventually oxidize and then delaminate at the most inopportune time, causing brake failure. I'm hoping not...

 Here are two types of cable stops. On the bottom is the CF cable stop as explained above. On top of the tube I bonded some cable ends directly to the tube.

To fasten the cable stops, first I glue them down with some JB weld, then after  that cures I add chopped carbon over the top and to fill in the sides.

Here's the front brake with the cable routed. After I add another layer of CF around the head tube, I'll bond on a short chunk of CF tubing to guide the cable going to the front brake. 
 I received the Rolhoff cable connector from Hans of Elan. Not cheap but they do the job, fixing issue #3. Also here you can see the titanium hose clamps.
 Here's a close up of the hacked up up forte brakes. Also you can see the derailleur cables on top of the tube.
 Time to make the seat pad. I bought a bunch of Zote foam from Garrie a couple months ago. It is very lightweight and a has the right give for seat foam. I really like the seat pads Don Smith makes with the routed lines, so I decided to make something similar. I decided on curved ribs to allow the sweat to drip out. I taped the foam to the board to prevent it from sliding around. Using a 700C wheel for a router guide, and following lines marked every 1" on the board under the foam, I carefully routed the ribs. You need to go back and forth once with the router to remove the fuzz.
Here's the  completed seat pad. I touched up the edges with a belt sander, which is not quite as nice as one of Don's pad's but still looks fine.
 Here's the cockpit view of the handlebars.
 Here's the modified Shimano shifter. You can see where I filed on it. Yes, it does (barely) shift the SRAM 9 speed rear derailleur through all the gears.

3/09/2010
The juxtaposition of nice weather, dry roads and a rideable stickbike occurred today. After a shaky start, I took it on the 5 mile test loop, and it actually felt pretty good.

On the plus side:
+ bike rides nicely.
+ trail seems right.
+ cockpit position feels right and is comfy.
+ brakes & shifting work well
+ seat and frame seem solid when cranking on it.

On the minus side:
- dang that tiller boom is long. It may take some getting used to.
- handlebars do not feel solid.
- needs a head rest.
- can't tell if it's the tiller or some kind of torsional frame twisting, but at low speeds some funny corrective actions were required to keep myself going straight.

Overall though, a good first ride!

Now I need to install the front shifter tube and maybe reinforce the handlebar tiller.
3/13/10
After much mucking about trying to get the angle right and figuring out the right combination of wires and tape to hold the derailleur stem in place while the epoxy cured, the derailleur tube is in place. I used another chunk of the CF golf club stem, with a braze on type derailleur. I also added another cable stop to the side of the main tube, behind the BB. Shifting is good.

 

The CF headrest that Garrie Hill made for my ti-cuda project many years ago was resurrected and works great for this bike.

I made an attempt at reinforcing the handlebar, but it did not work out so I removed it. Total weight is now a hair under 20 lbs with the heavy pedals and all the components, seat pads, etc.

3/28/10
I have had several rides on the bike now, and it seems fast but is still takes too much concentration. to ride comfortably. Also, it seems really high to me.

So, how do I fix it? Remote Steering? It would work, but it would look really funky on this bike.
5/18/10
Underseat steering? I rigged up a test to see if it felt any better than the tiller. Nope! It was worse!

After some back and forth posting on the recumbents forum, the consensus was that the handling issue was caused by too much weight on the rear wheel. Looking at my bike from that aspect, I can see that I have over 70% of the weight on the rear wheel. Ideally the weight distribution would be 50/50. That would not be so bad, but my seat is laid way back and I have a long tiller, both of which make it harder to control the bike.

Wider handlebars like those used by Bacchetta and others help to compensate for the rear biased weight distribution common on stick bike (high racer) designs. I'll try that before hacking this bike up.

If that doesn't work, I'll need to make a bunch of compromises which will make it heavier, and make the boom longer (more flexy!). It will look cooler though. Here's a mockup.

5/22/2010
I cobbled together some superman bars for the stickbike and gave it the "can I ride across the basement" test. Yes I can. It seems the the wide bars on highracers make up for the less than ideal handling inherent in that design. This gives me hope that I may not have to hack the bike up.

I think I'm going to go forward with adding the superman bars for now so I can actually ride the bike while there is summer left, then maybe this winter I will hack it up to make it more of a Euro high racer.

6/03/10
I ordered a set of Bacchetta long-reach superman bars and tried them out on the bike. I could not reach them. I added 8" extenders and then I could reach them, but the bars were too long and hit my thighs. I give up. The stickbike type of bike won't work for me with a laid back seat. Back to the drawing board.
Steve Delaire noted a basic recumbent bike design rule that I am violating. This is that your head should be forward of the tire contact patch. Having your head forward of the rear wheel is especially important when you are laid back like I am. This is probably why the bike feels squirrely.

The only way to fix this is to lengthen the boom a bunch and push myself way forward. This will also get me closer to the steerer tube so my reach to the handlebars is not as extreme.

Here I am racing Dennis Grelk's Bacchetta last fall during the Hawkeye Downs HPRA races. We had to push the seat way back which made it more upright, but I still had a tough time reaching the bars.

It's unfortunate that this design does not work well for taller riders, but that's what hack saws are for!

I spent a couple hours drawing the revised design, then hacked the boom off my stickbike.


2010 - Z Frame HighRacer Conversion
6/06/10
Here's the revised drawing. It shows that I need to add 6 inches to the boom, and tilt it down 15 degrees. After doing that, I need to Z the frame to keep the same 8" height distance from seat bottom to BB. Oooh. Seat height is reduced from 24" to a comfortable 19", CG is close to 50/50, Tiller is short.
To ensure a good mechanical connection between the old a new boom sections, I needed to make a sleeve. I made a sleeve mold from a chunk of aluminum tubing, and used some foam to press the CF into the sides of the tube.
This is the boom with the sleeve holding the old section to the 6" extension. To attach the 6" extension to the main frame, I will need to use an inner-tube to bladder mold a few layers of CF to the inside of the tube at the 15 degree bend.
I cut and pasted myself onto the revised drawing to make sure the riding position is the same and that my head is forward of the rear tire patch. Yes!
7/05/10
CFed the boom back on and hacked the main tube to bits. Here it is taped hack together with a 5" section of tubing added
Checked with the seat and idler to ensure the fit. I will need to revise the seat stays.
I put the wheels on to check the angles.
I put a single layer of CF on the top joint to hold it together while I add the Kevlar sleeve to the added section.

The white bandages are peel ply tape that I use to mash all the layers together. Any excess epoxy weeps through the fabric weave. The epoxy doesn't stick to the peel ply tape so it can be removed after it all cures.

7/19/10
Time goes by and I have Kevlar and CF wrapped the rest of the joints. Sorry no pictures, they would just be of more black tubes wrapping in bandages. Next I will need to add new seat stay mounts to the rear stays, re-route the brake and shifter cables, and then start re-adding the parts.
7/24/10
I peeled off all the peel ply, put the wheels back on and did the bounce test. Not bad, it's as least as stiff as it was in stick bike format. Made some CF seat stay tabs using CF plate I got from Mark Anderson. Very stiff!. Hacked 6" off the old seat stays and JB welded the assembly in place in preparation for actual bonding. Hacked over a foot off the tiller handlebars and JB welded into (hopefully) the right position.
The bike looks nice, like a lowracer with an impossible large front wheel.
8/29/10
Here's the bike after copious generation of carbon dust, and partial assembly. The test ride across the basement went well, the bike now handles fine.
Due to lots of reinforcement, The bike is stiffer now than when it was a stick bike. Weight with everything but the brake housings is still only 20 lbs. Cool!

Next I have to re-run the brake and shifter lines.

10/15/2010
I raced this bike (without the flag) at the Iowa HPRA races in September. Average speed for the hour race was 23 MPH, which is about 2 MPH slower than the NoCom, but 3 MPH faster than the Bacchetta ti-Aero I raced there last year. It handles nicely at speed, but due to the lower chain's interference with the front wheel, it does not go around corners well at low speeds. Also the frame is a bit flexy, which is good for bumps, but bad for power transfer. I still have some more tweaks to do, but it's a decent ride.
11/08/2010
I decided I needed to actually see where the flex was occurring, to see if I could fix it easily. If it's in the joints I can cut a slot lengthwise through the joint and then bond in a carbon plate. Click here for the full size video.

I'm also going to use an idler to raise the non-power side chain, as it restricts the wheel movement too much in the "down" position.

 
12/10/2010
I moved the idler behind the seat in hopes that it would help the frame flex. Cranking on it, it does seem to flex less.

In conversations with Larry Lem, he notes that his fastest TT times were on his dual 650C highracer with dual disk wheels. I will try this bike with dual disk wheels next year and see how it fares.

11/06/2011
I have been riding this bike weekly all year, and really like it. It handles well, goes up hills easily because it is so lightweight, and seems fast. It's certainly not as fast as the Nocom, but is much more civilized.
Here's the rear view. I ride with that light day or night. It is very bright and can be seen for miles, even in the day. It's a magic shine tail light.

Specs:
Weight: 20 lbs
Seat height:19 inches
Wheelbase: 48 inches
Seat angle: 25 degrees


10/5/2012
The BB mount aluminum front derailleur post finally cracked enough times that it was not worth epoxying together again, so I made a derailleur mount out of CF plate. It took several days of tweaking but it seems solid now and the alignment is close enough so that it works well.

I need to reinforce some of parts I attached with JB Weld with some real epoxy and CF, but it seems to be strong enough for a test ride now. I also added short CF tubing stub to mount the headlight to. The CF plate is pop riveted to the boom tube and epoxied.


 
3/16/2013
I'm getting the bike ready for the 2013 riding season. I added a Bacchetta Brain Box bike bag to the back of the seat to replace the water bladder bag hanging on the side of the seat which was probably less than aero. Also I obtained a used rear CF aero wheel, with power tap hub. I looked on Ebay for a front CF wheel to match the rear for  a couple months and finally got disgusted and bought a new wheel direct from China.
6/28/2015
Update - I have been riding this bike at least weekly (except in the winter!) for almost 5 years. It has been holding up well. Occasionally I sand the CF tubes and add another layer of epoxy as they are still a little rough but it's not very noticeable. It had been very reliable until yesterday when the front derailleur mount failed due to a JB weld failure. Today I re-glued it and reinforced it a bit with some chopped CF. Also I have to buy a new front tire. The old one has a bulge in the sidewall due to getting worn through by contact with the chain, which rubs when I turn sharply..

Dual 26" FWD Gravel Bike Conversion
1/11/2021
This bike has been my main ride for the past 10 years and is still a great bike for paved trail and road riding. My needs have changed over the years though. I'm now looking to trade off some speed for comfort and gravel ability. I'm going to raise the seat 10 degrees, trade in the 700c wheels with narrow tires for some 26" wheels with wide tires, change the bike to front wheel drive (FWD) and convert to disk brakes. I will probably need to change the handlebars and brake mounts as well. Here's a mockup.
The main reason that I'm changing to FWD is because I'll need to use a much wider fork for the wide 26" tires. The chain currently passes next to the fork and has actually worn though some of the carbon fiber over the years. The chain would have needed a bunch of idlers to route it around the fork. I'm pretty happy with my other FWD bikes so it makes sense to convert this one to FWD as well. I have ordered a full carbon MTB fork (pictured) and will cut it, widen it, and add a derailleur hanger to support the MTB rear wheel.
Dennis Grelk, who has had a lot of gravel bike experience, says that a supple 2" tire should have enough passive suspension to negate the need for any suspension for gravel use. This is a good thing. Also he recommended Mavic Crossmax SL as a good lightweight 26" gravel wheelset. Ebay here I come.
1/20/2021
I lost some Ebay auctions. The Mavic Crossmax wheels are in demand and are expensive. Decided to buy these CrossRide wheels on AliExpress instead. Are they real or knockoffs?  The stated weight is 1800g and the Crossmax SL wheelsets are 1390g. That's about a pound more but they are almost exactly the same weight as my existing 700C wheels so it's all good!  I guess I'll find out what I have in a month or so when they arrive on the slow boat from China.

While I'm waiting for the parts from China I can work on the raising the seat. Also I need to think about how to fit a 100mm front wheel into the 135mm rear dropouts.

1/27/2021
The seat is now remounted. The back portion of the seat was at 25 degrees, now it's at 35 degrees. It looks pretty close to my mockup above. Now I need to rebuild the seat stays as they aren't adjustable.

I found my CF tube stash and it looks like I don't have proper sized tubes for the seat stays. I have 10mm CF arrow shafts which are a bit flexy and some 20mm tubes that look massive. Decided 15mm looked about right and ordered a couple 500mm long tubes from ebay.

I'm looking at tires. My existing Vittoria Corsa tires are 225g.
Here are the ones that I am considering:
- Serfas Drifter 26" Bike Tire - 26" x 2.0". - 830g
- Schwalbe Super Moto-X Tire - 26 x 2.4. - 1095g

2/5/2021
The beefy CF disk brake fork arrived. Here's a mockup of how it will look after I widen the dropouts from 100mm to 135mm. I will have to leave plenty of clearance for the disk brake and wide range gear cluster.

The seat stay tubes arrived as well. I checked the x-seam on the seat and needed to move it a bit closer to the BB. Fortunately the seat bracket allowed the movement.

I decided on the Serfas Drifter tires. The brain trust noted that Gravel tires that have small knobs are better for gravel use than the smoother tires I chose but I'm not ready to give up the road performance yet. Maybe later...

I should be able to get a 135mm axle to install into the front wheel so I can mount it into the bike's 135mm rear dropouts. I'll need to see what fits in there after it arrives.

2/8/2021
The 15 mm seat stay rods rods arrived and I filled and slotted the ends to fit the seat stay brackets on the seat and rear wheel stays.
2/9/2021
Here they are installed on the bike.
2/14/2021
I temporarily installed a hub, brake disk, and brake to ensure I have proper clearance. It looks like I can cut the fork right above the disk brake mount.

Garrie Hill is making some carbon plate for me to use in widening the fork and creating a derailleur hanger.

2/15/2021
Here's the fork in the jig. This will keep it straight while I cut it and piece it back together.
2/19/2021
Cut the forks with the hacksaw, spaced the dropouts to 135mm and centered them. I'm considering whether to remove some length from the fork to bring it back to standard MTB fork length or leave it longer in case I want to use a 29er wheel.
2/21/2021
I did some measuring and took 1.5" out of the length of the fork. This new fork and my existing 700c fork seem to have about the same rake but the MTB fork is longer. After removing the 1.5" the axle to bottom headset race distance is 16" vs 15" on the 700c fork so I will have a bit more trail.

I cut two CF extender plates from the ~1/8" CF plate. After measuring every which way to Sunday, I "tack" JB Welded the extender plates into the fork. I had to build a small foam box and use a space heater in the garage to make sure the epoxy cures.
The next step was to test fit a wheel to ensure the fork was straight. First I had to file the dropouts to get the hub to fit as the fork's dropout width was undersized. While doing that I managed to break one of the JB Welded forks loose.

I filed the dropouts, put the fork back into the jig, re-applied epoxy and waited for the epoxy to cure under the space heater. After it cured I test fit the wheel and it looked pretty good. I will have to make a small adjustment to dropout depth on one side.

3/2/2021
Next, the excess CF plate was trimmed off and the area was sanded with course sandpaper to give the epoxy and CF a nice rough surface to hold onto.

Scrap CF was cut into small pieces to be used as fillet material on the inside angles. CF cloth was cut into appropriate sized pieces to be used to lay over and reinforce the outside angles. The layup was wound tightly with electrical tape.

There's about 2 layer of CF wrapping the joint. It looks a little weird but it feels very stiff.

I laced the 29er rim back onto the WTB 29er rear wheel I had modified for trainer use on the NoCom. It looks like I can fit a 29er wheelset with fat tires on both the front and rear of this bike so if those wheels from China never show up I'll use this 29er front wheel and will need to source a 29er rear rim. Looks like WTB doesn't make these wheels any more but the DT Swiss 533d 29 rim black - 32h is a good match.

Filed a bit out of one of the dropouts to properly center the wheel. Looks good!

3/04/2021
Cut the derailleur hanger out of the 1/8" carbon plate that Garrie made using the existing hanger on the bike as a template. Tapped it 10mm x 1.0 for the derailleur. Tapped a thin nut that was close in size to use as a steel backing nut. I will epoxy the nut onto the CF hanger with some JB Weld and then I will use some carbon and epoxy to firmly attach the hanger to the FWD dropout.
3/7/2021
Applied a layer of epoxy to fill in some of the imperfections then sanded it and sprayed it with some clear lacquer. After a finer sanding and another coat of lacquer it should be done.

Attached and filleted the derailleur hanger with chopped CF and epoxy. Wrapped in tape and used some foam rubber to ensure good compression.

Had to space the disk brake out with 3 5mm washers to give proper alignment with the disk brake.

Ordered the rear 29er rim and spokes in case the 26" wheels never show up. I may just end up just using the 29er wheels,

3/13/2021
Parts to build up the rear wheel arrived. I built the wheel and installed the tubes and tires. I decided on the 42mm Specialized "Trigger Sport" tires for these wheels because it didn't look like the 2" wide tires would fit in the rear.

This picture shows the 135mm axle I ordered to space the 100mm hub out to 135mm. I installed it in the front hub for use as a rear wheel. I used the extra bearing cones that came with the axle as spacers on the axles and serendipitously the spacing ended up 135mm.

Here's the bike with both new wheels installed. I still need to install the rear brake caliper. The rear dropouts are drilled for disk brakes but I'm sure I'll need to do some custom brackets to work with the narrow hub.  Handlebars will need to be modified or rebuilt as well.

It weighs 24lbs as shown.

This picture shows the clearance between the tire and the frame. Looks good!

I now have no need for the 26" wheelset that is probably still on a container ship in the Pacific ocean.

 

Here's the rear brake situation. I need to build a CF bracket to bridge between the rear dropouts and the disk brake caliper. I am using CAD (cardboard aided design) to design the template for the bracket.

I ordered a Fenner VA5001 5" pulley for use as the power side idler. I was going to use the TerraCycle 23T idler that was already on the bike but the Fenner idler is so nice and quiet and seems efficient on my three other FWD bikes so I decided to do the same here.

3/18/2021
The wheelset arrived from China and I mounted the Serfas Drifter tires. They are Mavic Cross Ride Disk wheels. They look nice and feel light. It does look like it will be a bit more of a project to convert the front wheel to 135mm so I'm going to put these aside until after i get this conversion completed.
3/23/2021
Worked on extending the steerer tube clamp to raise the handle bars and improve the clamping ability. Previously I had used a hose clamp and a small screw to help the CF clamps. I used a chunk of steerer tube sized aluminum tubing to mold it over. I had to stick it all in the freezer after it cured to remove the tube. It was really tight! Chopped off the old handlebars and I will rebuild them with some 5/8"-ish CF tubing.

This picture shows the steer tube clamp before any cleanup.

Built the the CF brake bracket and installed the spacer for the brake disk. The spacer also gives me a way to attach a chainring behind the brake disk for potential e-bike use. Next I need to cut out and fasten some tabs to mount the brake caliper.
3/28/2021
I cut out the tabs for the rear disk brake caliper bracket and JB Welded it in place. Several hours later I checked it to make sure it was all square and then added 2 layers of CF to each side of the tabs, overlapping the main bracket. I covered the mess with a piece of plastic them used the foam rubber and tape method to compress it all. After several more hours I unwrapped it and peeled off the plastic. Looks good, time to clean it up and drill some holes.
Drilled the holes in the CF bracket tabs and JB welded some lock nuts in place. Test fit shows a bit of adjustment is needed.

4/11/2021
Added a CF shim and now it works nicely.

The CF tubing to build the power idler axle stub showed up. These tubes all fit together. Roughed up the tubes and glued them together with JB Weld. The nut fits inside the biggest tube and was also glued in.
Used a holesaw to cut a hole in the side of the frame next to the head tube.
Glued the axle stub into the hole and built up a fillet around it with CF and epoxy.
Test mount of the idler. Next will be adding the chain and the return idler.
4/19/2021
Created the chain return idler. The idler is a cut down skate wheel re-used from the previous drivetrain and the bracket is made from flat CF plate that I bonded together using chopped CF on the inside and a few layers of CF fabric wrapped around the outside.
   

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