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How To Build Your Own Time Trial Bike

This how to will give you an idea about building your own Time Trial bike from scratch. I have started my blog post following my thought process from selecting the frame, components and the process of ordering a Chinese carbon frame. You can start reading from the beginning here or jump straight in if you are keen to see the build process of this TT bike.

I will be going through the build process that I took. For some of you who are about to start you own TT bike build, I'm sure that you will pick up some good information here. This may help you make a decion on building your own bike, or give you an idea of what's required. 


Frame Inspection

After a carefully inspecting the inside and outside of the frame and the fork, I was looking for any imperfections in the carbon lay-ups and any excess epoxy inside the frame. I didn't find any imperfections on the frame apart from some over spray from the paint around the head tube of the frame where the headset bearings will sit. This wasn't a big deal, all I had to do was sand it out. I started with the 400 grit sand paper then finished it off with the super fine 800 grit.

Before I started to sand the over spray from the headtub bearing race, I placed masking tape around the area where I didn't want the sand paper to touch. This will prevent scratches to your paint work.

Carfully sand down the bearing race, top and bottom. Make sure that everything is nice and smooth, this will allow the bearing to sit flush with the frame and prevent any creaking noises later.


Installing The Breaks

The next thing I did was intall the front brakes to the fork. I got the TRP TTV brakes with the frame from China which was half the retail price in the USA. The down side of this is that the brakes didn't come with any installation instructions. This wasn't a deal breaker for me as it wasn't too hard to install. 

Locate the spring hole on your fork then place the break arm with the springs leg down in the hole. Break arms are easily indentified from left and right as they only fit that way so you won't have any problems here.

When tightening down the brake arm make sure not to over tighten it as the screw thread already comes with locktite (blue paint thing), this will stop the screw from reversing out from vibration or movements from the brake arm itself. If you over tighten the screw, your brake arm will be locked in a fixed position and will not pivot when you pull your brake lever

To install the rear breaks you need to mount your bike frame to a bike stand, if you do not have one you can place your frame upside down on a soft surface to prevent damages while installing the brakes.

Here you can see that the TRP breaks fits very flush with the frame, not the easiest to work with but definably one of the nicest brakes to look at.

Tips: Leave the brake shoe loose on the brake arm during the installation of the brake arm. Once you have tightened down the brake arm then you can swing the brake arm in place and tighten the brake shoe while aligning it to the frame or fork


Installing The Fork

For all of my bicycle work I use boating grease. The reason I use boating or marine grease is that they don't wash away so easily. For a triathlon bike you are going to ride it after your swim, it could be fresh water or even worst, salt water. After your swim water can be dripping down on your bike, washing way your grease. boating grease may not be as low friction as some of the other light greases but only a lab test would show the difference, in a real world exercise its not going to slow you down that much.

To install the fork, first start by greasing up the fork crown which will support the bottom bearings for the headtube.

Apply some grease to the ball bearings, both inside and outside then place the bearings on the fork

Apply some grease to the bearing race, both top and bottom of the head tube.

Slowly insert the fork steerer tube through the head tube, making sure that the bottom bearing sits flush with the frame and fork.

Once the steerer tube is visible from the top of the head tube, place the top bearings into the bearing race. Again, apply grease to both the inside and outside of the bearing housing before installing it.

When ordering a complete frame set or buying a new headset which includes the bearings you should receive the bearing washers which look something like the image below

The washer with a split goes in between the fork steerer tube and the top headset bearing. Once you install this washer it will temporary hold your fork in place while you install the stem.

Slide the split washer all the way down to make a snug fit between your fork steerer tube and the top headset bearing then place the flat washer on top of the split washer.


Installing The Stem

With all the headset bearings in place, try not to bump the fork or it will miss align your bearings. Carefully slide the stem on the fork steerer tube, then tighten the two screws which connect the stem to the front of the fork. For this task you will only need to finger tighten the screws as these two screws are the screws that pull the stem down, compressing the headset bearings. Over tightening the screws here will put too much pressure on your headset bearings and will make it hard for you to steer your bike.

Turn the fork over to the left to expose the fastening screws on the side of the stem. Normally on a branded stem there would be a torque rating printed on the stem somewhere, indicating the required amount of torque for fastening up the screws. In this case, the Chinese made product did not come with any specified torque guideline. I tightened the screws up to 5Nm, this is only from experience so don't competently take my word on this.

After the stem is locked in, the next bit is to install your handlebar. At this stage I got carried away and forget to take any photographs of the work. To install the handlebar, place the handlebar on the stem. This stem has a steel rod which the screws from the top cap of the stem will screw into. Make sure that when you look down from top of the stem, you can see the screw holes before placing the top cap on. On the top of the stem you will see four screws to hold down the handlebar. I tighten them all down to 5Nm.


Installing The Cable Housing

Now that you have your frame and fork setup the next task is to install the cable housing. Since this bike frame has internal ports for cable housing, with most parts of the frame still exposed it makes it easier to run your cable housing before installing anything else on the frame. 

Start from front to back, Insert the brake cable housing on the base bar of your handle bar. I started with the front brake first since it's the shortest cable run and the easiest. The best way for installing the front brake cable housing is to push the cables from under the handle bar through to the end of the base bar where your brake handle will be installed. 

Tips: make up a small hook out of a coat hanger to help you pull out the cables from tight spaces.

The next cable I worked on was the front derailleur cable housing. Start by inserting the derailleur cable housing though the aero bar, once the cable housing comes out the back of the aerobar, insert the cable housing into the top cable entry port on the top tube of your frame. The cable will run down a dedicated cable port in the down tube and out the bottom. 

Getting the cable out at the bottom is a very challenging task, you will need to poke your finger in via the bottom bracket and push out the cable housing to the exit port and at the same time try to hook out the cable housing with a coat hanger.

To get this cable housing out it took me a very long time and a lot of bashing my head into wall action. The next cable to run is the rear break cable housing. Start by inserting the cable from under the basebar just like the front brake cable, once you have one side of the cable housing poking out at the basebar where you will later install the brake lever you can insert the other end of the cable down  into the entry ports on the top tube of your frame and down the downtube (same as the rear derailleur cable housing). Since the rear brake cable has to exit at the same port as the front derailleur cable housing, you end up with two cable housing sharing the same exit port, this time it was even harder to poke the cable housing out. Be patient, you'll get it eventually. 

The next cable to run is the rear derailleur cable. To start, feed the deraileur housing cable from the front of the aerobar. Once the cable housing exits the aerobar, insert the cable down the entry port on the top tube of the frame. The cable housing will run down the cable port in the down tube. Once the cable reaches the bottom bracket, push the cable up with your fingers so that the cable continues down the drive side of the chain stays.

The rear derailleur cable exit port can be removed to allow easy access to the cable housing.

Once the cable housing is visible at the exit port, use a hook to pull out the cable housing.

Once you have pulled out the cable housing, insert the cable exit port cover back on the cable and screw it back on the frame.

Install the derailleur shifters and break levers to the aerobar and base bar to estimate the cable housing length.

After all the cable housing has been fed through the frame, the next step is to trim all the cable housing to the correct length. Be sure to use the correct tool to cut your cable housing, use a high quality cable housing cutter to get a clean cut.

Insert cable end caps to both ends of the cable housing before feeding the ends to the frame, brake levers, and derailleur shifters.


Installing Gear and Brake Cables

The plus side about having internal cable routing and running full cable housing all the way makes installing gear and break cables very, very easy. I won't be going though how to install the derailleur as I have already posted an article here

For this build I used the profile design brake lever, it was one of the lightest brake levers around. This lever uses mountain bike brake cables (the right one in the image below), NOT the standard road bike brake cables.

For me I started with the front brake since it was the easiest and shortest cable to run. Start by inserting the brake cable though the brake lever, keep pushing the cable until the cable exits the cable housing. Don't forget to add the brake cable end cap.

The front brake comes with an inline barrel adjuster and a 90 degreases bend cable guide, feed the brake cable through until the cable exits the barrel adjuster.

The cable lock nut is a torx nut. Use a T10 wrench to tighten it up

Insert the brake cable through the lock nut before placing the lock nut and the cable on the brake arm.

The front brake can be adjusted by the screws on the side of each brake arm to align the brakes to your rim. At this stage it is good enough to move on to work on the next cable. You can fine tune the brakes later.

The rear brake cable last was the most difficult to setup. The cable housing must be at just the right length for the brakes to work. Start by feeding the brake cable from the brake lever until the cable exits the cable housing under the bike. Feed the cable though the 90 degrees brake cable guide before placing it on the brake arm.

Tips: The perfect length was 5cm from the cable exit port, that gave it enough length to form a nice bend without pushing on the brake arm. 

Next cable to run is the front derailleur cable, insert the gear cable through the shifter.

Push the cable though until the gear cable exits the cable housing at the bottom bracket under the bike.

Once the cable exits the housing under the bike, grab the cable and insert it back up into the guide hole under the frame. The cable will then exit on the drive side of the bike next to the front derailleur mounting point.

The next cable will be the last one, the rear derailleur cable, this was the easiest cable to work with since we have full cable housing running through the bike frame. Start by inserting the gear cable through the shifter on the aerobar. Keep pushing the cable in until the cable exits the cable housing at the rear derailleur.

For detailed instructions on how to setup the rear derailleur, see my how-to here

Installing the cable housing and setting up the cable on the bike is the hardest task during a bike build. If you have come this far then you are nearly finished.


Installing The Bottom Bracket

The bottom bracket I have chosen was the Shimano Dura-Ace 9000, SM BB-9000. It has smaller bearings, is faster and an over all lighter unit compared to the previous model. This bottom bracket requires an adaptor for tightening up. Not to worry, it comes free in the box.

Start by applying some grease to the bottom bracket thread on the frame, this will prevent any creaking noises further down the road.

Next, insert the drive side of the bottom bracket from the drive side of the bike. Then hand tighten the non drive side of the bottom bracket. It should look like the image below if you are looking down on the bike from the front of your bike.

Grab your bottom bracket adaptor and attach it to your bottom bracket wrench.

Shimano recommends tightening it up to 30-50Nm. I don't have a torque wrench that goes beyond 15Nm so I had to use my personal judgment for this task. All I can say is, crank it up tight but not crazy tight.


Installing The Chainring Crankset

Start by inserting the drive side crank arm (the side with the chainring on it) through the bottom bracket, push hard with the palm of your hand until the crank arm sits flush on the bottom bracket.

Insert the non drive side of the crank arm, look for the the indentation which is opposite the hole, if the hole is at the 6 o'clock (facing down) the non drive side crank arm will have to sit up at the 12 o'clock (straight up).

Locate your crank arm fixing bolt. Thread the fixing bolt on by hand then use a Shimano crank installation tool, TL-FC16 to tighten up the crank arm fixing bolt. 

On the non drive side crank arm, you should see a little pin/plate slotted in between the crank arm. 

Push the pin down so that it locks into the hole of the drive side crank arm. This will prevent your crank arms from coming apart during your rides.

Alternately tighten up the crank arm bolts with a torque wrench to about 13Nm. Make sure not to over tighten one side, this could cause your crank arm to deform or damage the bolt threads.

From here you have mostly finished your bike build. All you have to do now is install the chain and wrap the bar tape. I have already written up a detailed post about how to install your chain here.

Thank you for reading, I hope this guide has given you some help in your bike build or provide you with some more information to help you with your new bike project. At this point when I am writing this article the bike has been through a lot of testing and a few races. It performed very well and looks apart on the field.