# GT Grade Brake upgrade



## dennetti (25 Apr 2020)

I have a GT Grade with the standard tektro mira mechanical disk brakes. I find them very weak, and wondered if anyone could suggest an upgrade, such as a replacement caliper. Not sure what would be compatible. I think the bike is 2015/2016 model. Thanks for any advice.


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## Justinitus (25 Apr 2020)

I upgraded the Miras on my Diverge to TRP Spyres with noticeable improvement in both brake feel and stopping power. 
You‘ve also got the option of the TRP HyRd which is a hydraulic caliper operated via cable. Google reviews on these as they seemed a mixed bag to me. 
As your bikes 4yrs old, I would change the cable inners and outers at the same time.


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## dennetti (25 Apr 2020)

Thanks for the recommendations, I'll check these out. Cheers


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## lane (25 Apr 2020)

TRP HyRd I had on my GT grade. After it was stolen I also had them fitted on my new bike. True some don't get on with them the set up needs to be correct but not had an issue myself.


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## dennetti (25 Apr 2020)

They have them on Chain reaction, reduced to £42. Do you think they should bolt straight on?


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## I like Skol (25 Apr 2020)

I was very, very happy with my Spyres but since swapping out the original pads have not quite found the same bite. I do have some genuine Shimano pads on order so hopefully these will perform better?


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## dennetti (25 Apr 2020)

TRP Spyres, that is.


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## dennetti (25 Apr 2020)

I'll go for it, thanks guys.


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## lane (26 Apr 2020)

dennetti said:


> They have them on Chain reaction, reduced to £42. Do you think they should bolt straight on?



Well they were fitted on my GT grade so probably yes


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## Justinitus (26 Apr 2020)

dennetti said:


> I'll go for it, thanks guys.


Just make sure you get the correct version - post mount or flat mount. Not sure which type your Grade has.

Don’t ask me how I know this..


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## dennetti (26 Apr 2020)

Thanks. My grade is post mount. I'm wondering if I need an adaptor as the mounts on my frame are 80mm apart, but the mounts on the new caliper appear closer than this, from looking at their image. I always struggle a bit knowing whether parts will be compatible. Cheers


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## Justinitus (26 Apr 2020)

As far as I’m aware, post mount calliper bolt holes are a standard size, so the adaptors that are already fitted to your existing brakes should fit the new callipers. Just take them off and fit to the new ones - make sure you get them the correct way up! 
If you’re replacing the cables, make sure you use a decent quality compression-less outer.


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## dennetti (26 Apr 2020)

Cheers. No adapters are fitted on this model grade, the caliper bolts straight onto the fork leg. Thought I'd keep the existing cables as they are not too old.


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## dennetti (2 May 2020)

Bought a pair of TRP Spyres on ebay for 60 pounds. I'm still bedding the pads in, but initial impressions: better feel and more breaking power, not mind-blowingly more, but significant and definitely worth the upgrade. They bolted straight on as you said. Plenty of room for adjustment up and down and forward and back. As an average home bike mechanic I found it a simple job. They look great too. Thanks again for your advice guys - really helpful.


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## Justinitus (2 May 2020)

Glad you’re pleased with the upgrade - good price too!
Just a small safety recommendation - the QR lever shoulD really be orientated either up or back to avoid accidental opening should it catch on something.


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## dennetti (3 May 2020)

Ah yes, thanks. Good point.


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## dennetti (15 May 2020)

@Justinitus. I've noticed there's a lot of friction in the rear brake cable which is preventing the brake "arm" from springing back. Maybe a should get the compression-less outer you recommended. Is this a typical problem with these brakes, or perhaps its the way the cable is routed on the GT Grade. I'm guessing this would reduce the friction in the cable...


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## Justinitus (15 May 2020)

It’s difficult to tell if it’s not routed correctly on your bike without a photo, maybe see if you can find a stock image of your bike online and compare with yours? 
If it’s the original Factory cable outer I’d like to think it’s compression-less, but of course it may have worn out and need replacing.
If there’s friction, if it were me, I would replace the inner cable first with a good quality stainless one and see if that helps - it could be gummed up or frayed somewhere and it’s the easiest part to change. If the old cable comes out rusty or gungy I have had success spraying a little GT85 down through the outer to clean it - but if you do this make sure you don’t get any on the brakes themselves!


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## I like Skol (15 May 2020)

Grade cables run in continuous outer casing down the underside of the down tube held on by 'claws' that retain rear brake hose/cable and both gear cables. These claws are screwed into threaded inserts in the frame. The brake and rear derailleur cables then run along the bottom of the chainstays on either side. There isn't really much scope for misrouting them.
What can happen, and is quite specific to the way the cables are held by the screwdown claws, is that the claws are overtightened and this crushes the outer casing causing poor gear shifting and sticking brake cables. Not a problem with traditional spiral wound casing as this is good at resisting crushing, but the longitudinal casing used for modern indexed gears and brake systems is easily trapped and squashed in this way. I think your grade will most likely have the longitudinal/compressionless outers so I would start by loosening off the claws and seeing if this improves things.


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## dennetti (15 May 2020)

Thanks. I tried loosening the claws as I thought this was probably the problem. It did help a little. I have already replaced the inner cable. I think the outer able has been crushed out of shape a little.


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