TRP Hydraulic Trail SL G-Spec Brakes: Rider Review

Our "Rider Review" article series features the honest reviews from verified purchasers of Worldwide Cyclery. They contain the photos, thoughts, feedback & overall review you are looking for. 

Brakes are a very personal flavor on each bike, with tons of great brands to choose from it really comes down to what you want the brakes to feel like. Raj is changing from Shimano SLX 2 piston brakes to TRP Trail SL G-Spec 4 piston brakes, not only an upgrade but also going from the more on/off feel from Shimano brakes to the smooth modulation of TRP brakes. Let's see what Raj thinks after a few rides on his new TRP brakes.

Raj's Review:

As I’ve become more confident on my bike and been able to push harder, I decided it was time for some four-piston brakes to increase my stopping power. I don’t live in an aggressive downhill trail area but there are many times on fast rides I found my two-piston Shimano SLX brakes fading. Originally I had my plans on getting the Hope X4 setup which was outside my budget. Great brakes as I’ve had the X2 Hopes on a previous bike but definitely more expensive than other four-piston options.

TRP Trail SL G-Spec Brakes

As such I kept researching brands, comparing brake modulating, fluid type, pad types, rider reviews, and bleeding processes. I knew that I wanted affordability, a system that took mineral oil and had more modulation. Coming from Hope and going to Shimano, you notice that Shimano has a distinct on/off feel which always left me locking up my brakes. Also having 2 pistons SLX Shimanos, I was didn’t have the same stopping power when bombing down hills and needed to stop quickly. I finally came across the TRP Trail G-Spec SL brakes. The price point was right and apparently they are known for their modulation. I know Code brakes would have been perfect for what I was looking and their install and bleed process is fairly easy, but I really wanted to give these TRPs a chance and see if they lived up to the hype. The TRP Quadiem brakes also looked like a worthy purchase but would have been overkill for my trail needs. So Trail G-Spec it is!

I already had Shimano Ice-Tech 180mm rotors, so I was in the perfect range for good stopping power as compared to a 160mm setup and not overkilling it with a 200mm setup. Keep in mind you may have buy caliper brackets and other matchmaker lever adapter once you install these brakes. Before fully installing I fitted the levers and calipers just to see if I needed to buy extra parts. Luckily my Shimano XT shifter adapter fitted perfectly with the right brake lever. The left lever, however, did not fit my dropper post lever but I was able to engineer a workaround with zip ties that are holding up beautifully believe it or not! Once I was confident my setup would fit, I pulled the old brake caliper and lines fully off and got to installing these bad boys.

TRP Trail SL G-Spec Brakes
The front brake install is pretty easy. Bolt the caliper on to the bike and cut the hose as needed. The hoses do need to be fitted with the brass end piece fitting which, if you haven’t done before, can be cumbersome if you don’t have the right tools. In this case, may want to pay your local bike shop to install these because you will need to bleed the brakes after. Once running the rear cable (which was an adventure in its own in my Stumpjumper) and hooking it up to the lever it was time to bleed. This was my first time to bleed brakes and I ended having to re-bleed the rear once but I got the front bled on the first try.

With that said these are not fun to bleed. I believe it’s once if the more time-consuming bleed processes out there based on my research. But if you are comfortable with working on your bike and have patience, it can be done. It took me about an hour to fully finish bleeding the brakes front and rear once I figure out what I was doing. You will have to get a bleed kit with hoses, syringes, and bleed blocks for this process. They also usually come with all the necessary bleed adapters for the Caliper and Lever. My total install time with bleeding was probably 3.5 hours which I think is reasonable given this was my first time doing this and having to run internal routing for the brake lines. Checkout the TRP YouTube video for bleeding these brakes which was very helpful.

On the Trail:

Finally, it was time to ride these bad boys! My initial thought was that they didn't have the same stopping power but realized quickly the harder you engage the lever the more power is put down. This was very apparent in fast downhill descents. Coming from the on/off feel of the Shimanos it took me a few minutes to recognize the difference. Once I figured this out the result was amazing stopping power that gave me more confidence in my riding and allowed me to ride even faster knowing what I had available with these four-piston brakes. The braking modulation was also a new feel for me and got the hang of it halfway through my first ride. I’m not entirely sure if I need to get more air out of my lever since at times it feels like it is getting close to the bars. But I noticed in times when I engaged the brakes harder the lever travel wasn’t as bad.

TRP Trail SL G-Spec Brakes

Final Thoughts:

Overall I’m super happy with the stopping power of the TRP Hydraulic Trail SL G-Spec brakes and they look really good with the all black look of the calipers and levers. Brake fading is not an issue and they continue to deliver power throughout my rides. My confidence has gone up and I find I can carry more speed with these more powerful brakes. The install process is pretty standard but the bleeding process is a learning experience, but I know next time I will get it faster. With that said I think it’s a really great product and worth the purchase. 

TRP Trail SL G-Spec Brakes


May 26, 2020

brakes › Rider Review › Trail SL G-Spec › TRP ›

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