Tektro caliper with Shimano levers

FreakyAmer

Hi all

this is my first post in this website. i am kinda new to this mtb scene. my bike has shimano m447 brakes. The rear brake caliper got broken. Now I have this tektro gemini twin piston brake spare caliper. I was wondering if it would be compatible with shimano levers as both use mineral oil. thanks in advance

cooldad

I doubt anyone has tried it but only takes a few minutes to see if it will work.

FreakyAmer

cooldad wrote:

I doubt anyone has tried it but only takes a few minutes to see if it will work.

lets see...fingers crossed. will update on how it turns out

rockmonkeysc

Extremely unlikely. Most probably very different fluid displacements.

dgmoose

FreakyAmer wrote:

cooldad wrote:

I doubt anyone has tried it but only takes a few minutes to see if it will work.

lets see...fingers crossed. will update on how it turns out

No need to depend on luck.

It will work 99.9%.

Here are some things to note:

1) Use the end fittings specific to the brands at each end. So, Shimano barbed insert and olives for the Shimano levers, and Tektro barbed insert and olives for the Tektro calipers.

2) The common interface will be the hose. Tektro uses 5.5mm OD hoses whilst Shimano uses 5.0mm hoses.

In general, if there is a difference of 0.5mm OD between the two hose requirements then the two ends can be connected to a single hose because the end fittings are compression fittings and the 0.5mm are within tolerances for it to work.

If the difference is 1.0mm then the larger of the two olive IDs will fail to be crimped onto the hose.

The ID of the hose is not too critical - it just means one end will either be too tight (in which case you just have to brute force the barbed insert into the hose) or too loose (but remember it is a compression fitting).

3) If you use a Tektro hose, then you will need to sand down or strip 0.5mm of the cosmetic layer in order to fit the olive at the Shimano end.

If you use a Shimano hose, then you will need to force the barbed insert at the Tektro end. And, you need to pad just the section of hose that protrudes out of the plastic cover tip otherwise the hose looks a bit too small for the hole.

4) Apply a light layer of grease on the threads of the shroud nuts before screwing them in. You should do a dry run by screwing the nuts all the way into the lever/caliper, note the number of exposed threads and remember not to exceed this absolute limit when you do it for real (otherwise you will strip the threads in the lever/caliper).

5) Push the hose all of the way into the lever/caliper until it bottoms out before screwing in the shroud nut. Maintain the pushing force until the olive is crimped onto the hose - this will ensure that the olive is crimped in the right place and is not crooked.

6) Tug the hose afterwards to make sure that the hose attachment is secure.

7) Use Shimano, Tektro, Magura or Halfords HLM Plus mineral oil for the bleed.

8 ) In general, if there is an external bleed nipple on the caliper (to attach a bleed hose) and a reservior cap on the lever then try the gravity bleed method (aka Hope method) first because it is less hassle. If not, then the two syringe method will work instead.

9) Tip:

Sometimes, when you remove the syringe or bleed hose (with a threaded fitting) from the lever, you may lose a drop of fluid that could introduce air into the system. To compensate for this lost drop, you could pump the pistons out of the caliper slightly, remover the syringe/bleed hose then spread the pistons back using a large flat bladed screwdriver before doing up the bleed screw in the lever.

EDIT:

I forgot to mention that you do not need to use brand specific hoses to setup Frankenstein brakes - the hose can be any generic hose that is rated as a high pressure hydraulic hose. Consequently, you could use Hope 5.0mm hoses (cheapest option) if you don't have either the Shimano or the Tektro hose.

rockmonkeysc

Getting it all connected up and bled won't be a problem.
The problem will be the difference in fluid displacements between the Shimano calipers and the tektro. The pistons are unlikely to be the same diameter meaning that you'll end up with either loads of lever travel or none.
You're moving tiny amounts of fluid so a small difference in piston diameter makes a big difference.

dgmoose

RockmonkeySC wrote:

Getting it all connected up and bled won't be a problem.
The problem will be the difference in fluid displacements between the Shimano calipers and the tektro. The pistons are unlikely to be the same diameter meaning that you'll end up with either loads of lever travel or none.
You're moving tiny amounts of fluid so a small difference in piston diameter makes a big difference.

I've been lurking for a while. It seems to me that this misplaced apprehension is holding you back from trying things out.

It will work because there are physical constraints and design principles/philosphies in place which dictates that there will never be a condition where levers will not operate calipers to a satisfactory degree.

Herdwick

But you may and up with a weak brake if tektro pistons are smaller than shimanos, or with more power if pistons are bigger but only ift he lever doesn't touch the handlebars from the excessive stroke, either way give it a try and let us know

rockmonkeysc

dgmoose wrote:

It will work because there are physical constraints and design principles/philosphies in place which dictates that there will never be a condition where levers will not operate calipers to a satisfactory degree.

That's rubbish. Not all Shimano brake components are compatible with each other so why on earth would they be compatible with parts from another manufacturer?
Just because you can connect the hoses doesn't mean you'll get usable function from them.
It's like trying to run Shimano gear levers with SRAM derailleurs. You can connect a cable and it will move the derailleur but the lever ratio is wrong so it doesn't work in a usable way.