Trek Speed concept rear aero brake adjustment

Posted by Ed Brennan on

 

Trek Speed Concept 1st generation stripping, cleaning and adjusting the rear aero brake

for  a PDF version please click the link below

https://cdn.shopify.com/s/files/1/1497/1072/files/trek_speed_concept.pdf?8812620474901050691

 

To day I am going to geo thorough the procedure for servicing and adjusting the rear aero brake on the Trek speed concept. The design of aero brakes is a great idea hiding the brake behind/ under the bottom bracket. The first generation of the speed concept although a great fast TT bike has to say the least has a few issues when adjusting even servicing. It is recommended that you remove the crank but it is not necessary, if you are going to service or replace the brake cable you may as well replace all of the cables even though they can be changed with the brake components in place it is a lot easier.

 

Before you start please ensure that you have a cable adjuster fitted near the tri bars so that when the pads wear you can adjust the brakes them selves, if there is not one buy the relevant part and install it once you have removed the brake cable. This is needed as the brake cable has to be cut extremely short leaving no room for pulling the cable through, if you do leave it too long when you replace the bottom plate the cable will push against the spring tensioning and pulling the brakes together.

 

Tools required,

  1. Alen keys 1.5,2.5,3,5.
  2. Gloves
  3. Chain oil to lubricate all of the other cables
  4. Lubrication spray GT 85, WD40.
  5. Petroleum jelly,
  6. No8 spanner/ socket
  7. Brake cable with a barrel end (mountain bike cable) if using the Bonrager tri bars, check before stripping it out.
  8. Head torch if completing the operation in poor light.
  9. Patients of a saint.

 

Put the bike in a work stand one that you can either turn the bike upside down or at least have the bars pointing to the ground and rear wheel to the air ( the rear wheel will be removed and install numerous times through out the procedure). Have the aero covering brake plate at head height so it is easier on the back, as with all bikes that have an aero style brake that are mounted in the vicinity of the rear of the bottom bracket this makes it a whole lot easier. Now that the bike is in the position required we should be looking at this!

There are 3 hex bolts that need to be removed the 2 top are a 3mm and the bottom lrft is 2mm. Unscrew them and put them in a safe place or magnetic tray so as not to loose them, before hand give them a clean and degrease and then remember to put some lock tight on the 2 3 mm bolts as they hold the brakes in position as well.

Once the bolts have been removed remove the cover and turn it over, it is going to be dirty beyond believe as a lot of road dirt can get in there. Give it a good clean and then it should be separate into 2 parts, aero brake cover plate and the black strut.

(remember the flat side of the strut faces down towards the ground) As you can see by the picture this one has been damaged by some road debris or something hitting it. Once the plate has been cleaned you can easily see the picture that gives the torque settings for each

 

Now with the plate off and cleaned ensuring I can read the torques and the strut removed and cleaned I am now left with the bottom of the bottom bracket looking like this

I have removed the brake blocks for ease, also I may as well clean them out and replace the pads.

I have put the 2 3 mm bolts back in loosely as I had misplaced my metal bowl (most probably magnetically stuck to something for safe keeping). I now squeeze the brake pad arms together and remove the triangle shaped wedge, this is what the brake cable bolts into and as the cable is pulled it in turn pulls the wedge widening the bottom and closing the pads to the rim, very simple but a nightmare to service for the first time. Once I have removed the triangle centre piece out I just cut the wire and always put it in a glass of parts cleaner to soak any grit out of it so it is easier to undo the 8mm bolt.

 

I now gently unscrew the 2 bolts and wiggle the and remove the rest of the brake. Which should look like this,

clean off the brake with some GT85 or similar ensuring that you do not get any on the brake pads (if you do sand paper them down) unless replacing them then it doesn't matter. Every time I remove pads I give the whole brake pad housing a good clean and de-gunge, you remove the pads on the Trek by using a 1.5mm( this does not usually come in with a set I always by more than one as they are easy to snap and loose). Now with the brake cleaned, pads replaced and the spring greased I can now clean the rest of the bottom of the bikes of all road grit and dirt, also if I am not replacing another cables I will lube them now with some Green oil chain lube by just dripping a bit down to ensure easy movement with minimal friction. I would always advise to change all of the cables if removing the brake calliper as it is better and easier to do it when the brake has been fully stripped down.

 

If replacing the cable, remove the old cable, measure the new cable against the old cable and install, attach the center pull triangle bolt facing towards the ground and tighten, ensuring that there is minimal cable just enough to put a cable end on otherwise when it comes to replace the bottom plate the brakes will adjust themselves, this is defiantly what you do not want.

Now we need to start the long laborious task of adjusting the brakes, place the rear wheel back in   you must be 100% sure that the wheel is centre and square in the drop outs if not you will set up the brakes for a wonky wheel this is not what we want ,tighten the skewer.

Push the brake calliper onto the struts do not bolt on, and ensure it is pushed all the way home on the pivot posts.

 

Ensure the pads are adjusted correctly to the rim, in line with the braking surface

 

Now look at the gap between the pads and the braking surface on the rim, these need to be an identical distance for optimal braking, if they are not you will need to adjust the brake either left or right depending to do this, carry out the following

 

  1. Remove the rear wheel.
  2. Remove the rear brake.
  3. Adjust the mount by unscrewing the 3 mm bolts moving the mount to the desired position retighten the 3mm bolts.
  4. Replace the brakes.
  5. Replace the wheel and ensure that both brake pads make contact with the rim at the same time when the lever is pulled, if not repeat the process until you achieve this.
  6. Finally adjust the brake via the barrel adjuster if needed.

 

Once you have completed the adjustment replace the strut and brake cover, if you have completed this correctly the brake will feel really good, this is a long and annoying procedure to adjust the rear brake, I would recommend replacing all of the cables at the same time.

I hope that this has helped in the nightmare that is the original speed concept brake.

 

 

 

 

 

 

 


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