TRP's Spyre SLC Caliper is a mechanical disc brake caliper for those of us who like to play with non-standard components and like the assurance of cable brakes when on wilderness trips or already have a set of perfect cable-operated brake levers and want to use them. They are lightweight, good-looking, easy to adjust, and with careful setup decently powerful. Who says you need hydraulic brakes to stop fast?
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TRP Spyre SLC Caliper - Technical details
TRP is a major player in the brake market making vast quantities of brakes for many bike brands for both the budget end through to the DH racing market not forgetting the adventure bikepacking market in between, which is where these Spyre SLC calipers fit in. TRP states that this caliper will work with all cable pull brake levers so whichever ones you have you should have no compatibility concerns.
The Spyre SLC is the top model in TRP's cable-operated range and has a silky smooth polished alloy caliper body with a dual push flat mount piston design that uses an ultra-stiff carbon actuation arm to push both pads towards the rotor as the brake lever is pulled giving the TRP Spyre SLC more solid feel and more power at the lever. This SLC version with its carbon actuation arm is said to provide a more solid feel over its alloy-armed and lesser brethren.
The flat mount caliper is a super small unit weighing in at 155g (slightly over the claimed 146g) and only 40mm wide. You will need to use a 140/160 adaptor for the front fork for a 160mm rotor but that's fairly normal. The Spyre SLC comes fitted with semi-metallic brake pads described as ultra grippy on their website and when they wear out or if you want to change them they are the same spec as Shimano M525/M515 pads so you should have plenty of choice for replacements.
Getting the best performance from a cable-operated disc brake relies on a good setup, using a compressionless outer cable, ferrules, and of course a compatible brake lever. Luckily for this test, I’ve got just such a setup from Microshift with the new Sword 1x 10 groupset and Jagwire's KEB-SL compressionless outer cable and stainless inner.
The Spyre SLC Caliper costs £84 per caliper but you may need to budget for cables (around £30) if you don't have a good compressionless setup already and possibly new rotors too. The caliper comes only in this finish which is fine by me. TRP 1.8mm rotors cost from £32 to £52 each. The adaptors cost £12 each. The total cost of the TRP parts would be £286 - plus your choice of lever of course.
TRP Spyre SLC Caliper - Performance
The setup is pretty straightforward. Mount directly to the frame flat mounts or use the specific adaptors for the rotor size and location on the bike, in my case a 140/160 adapter was required for the fork. Leave the caliper bolts a little loose. Thread the cable through the frame and forks and through the adjustable barrelled cable stop and pull hard to make sure all the ferrules are fully seated against the cable outers. Do not pre-engage the actuation arm, (a trick that can work wonders on the Avid BB7 btw), there is no need here and use a large grub screw to clamp the cable.
Next spin the wheel and make sure the rotor is as straight or true as possible adjusting any wobble with a rotor truing tool first. With those caliper mounting bolts loose pull the brake lever and whilst holding the lever with the brake on, do up the caliper bolts to get a good central fit above the rotor.
At least that’s one way of doing it, but there are others and sometimes that rotor is super wobbly. In fact, the TRP rotors supplied with the calipers for this review were amongst the worst I’ve seen in a long time. They required a lot of concentration and spinning to get them straight, but patience is a virtue and they are true now.
With the caliper tight on the bike, the cable clamped tight you can now attempt to dial out any excess travel that the system has. First wind in the pads so that they are close but not rubbing the rotor. This can be done with a 3mm hex key on both sides through the pivot of the carbon arm. It’s a deep fit to get to hex head to turn them, so a mini tool is not going to work on the inner pad adjuster due to the spokes. You’ll need a long hex key to access from the other side of the wheel. Next wind out the cable adjuster - yep, just like old rim pivot brakes - to take up any cable slack.
Now you’re ready to test the brake. You may find that hauling the brake lever hard has stretched the cable. It's actually more likely that you have just fully seated all outer brake housing into the ferrules right to their designated stops. There should be no compression in the cable at all. TRP does offer its own cable kit for this brake but once again it's extra cash at £30 and I already had the Jagwire kit laying about.
So now that you are fully set up you can go for a ride. And boy these brakes are actually pretty good. No, they are not full hydraulic power good, they still rely on you pulling the lever hard but they feel good, modulate well, and offer pretty decent power.
I have been testing them since the autumn of last year on various builds each time with the Microshift Sword groupset. My initial thoughts were that the calipers felt a little soft and lacking in bite. So after about six weeks or so of soaking wet riding, I swapped to a set of Race Matrix pads from Uberbike with a very marked improvement. Bite was much stronger, modulation felt better and they were quieter. I still thought there was some softness in the system so I reset all the cabling and ferules and found a small marginal improvement to the feel.
I rode throughout the winter like this on and off-road without any issue stopping. In fact, I was able to brake so hard and late, that I surprised a few riders how well cable discs can work. And yes they do, but after a full day of adventure Bikepacking your hands are more tired than other riders with hydraulic brakes.
The next improvement had nothing to do with TRP and is actually one of the disadvantages of testing kit that requires lots of different parts to make it work. A conversation with Microshift led me to swap to their redesigned Sword lever with its updated construction. With this new production lever, the brake was instantly a lot more solid and there is no question of softness at all left in the system, so regardless of any shifter improvement, the braking feel is genuinely 1st class now. Still, not quite hydraulic very good but a lot better than some I've used and more than enough for most people.
The carbon actuation arm pushes both pistons smoothly every time with very little cable feel. There is some obviously, but it's as light as it can be with the silky cable set up here and you can honestly forget about it being cable get on with your riding and feather the brakes when you need or pull hard and get an instant hard response when required.
So there you have it, the Spyre SLC caliper has a lot going for it in terms of its style and it will work with all of the older cable pull brake levers on the market so you can build yourself some crazy bike builds on the cheap. Well, you could if you didn't need to buy all the extras. But even if you had to buy everything, except the levers, at under £300 it's still about £200+ cheaper than the official price of GRX400 or SRAM Apex. The official price that is, as there are some outstanding deals out there today. But in Morocco, the Scottish Highlands, or Armenia you can fix these brakes with parts you can carry in a small bag in your frame bag easily, and a lot of people like that idea even if the furthest they will travel is the South Downs Way or King Alfred's Way.
TRP Spyre SLC Caliper - Verdict
TRP’s only direct rival at this level was the Avid BB7 but since Sram doesn’t offer a flat mount version that's no longer the case so it's these or much more expensive Pauls Component Klampers ($244 each) or Growtac Calipers (£340 pair) or cheaper units form TRP themselves or full hydraulic systems to choose from. In reality, a full hydraulic set might be cheaper if you search for a deal, but it will all depend on how much compatible kit you already have and why you are building your bike up like this.
The TRP Spyre SLC caliper is a great cable-operated disc brake for those who want the easier maintenance of cable-pull brake levers. So if you're building up old kit or you want to build an adventure rig or you just like the idea of simple cable mechanics, you cannot go wrong with these and boy do they look stunning. Light, powerful, and er nope sorry, not that cheap by the time you have bought cables and rotors but definitely worth the investment if you have the kit already.
1 comments
Ive had these on my gravel bike for the last 3 years. They have been perfect for me! Easy to setup and maintain. very effectively at breaking and stopping. In reality it's only the month-to-month adjusting of cable pull and changing the pads regularly required. I use BBB resin pads and ultegra shifters and rotors for better performance and silent use. I also use Jagwires non-comression wire housing like in the review. I've never used standard housing, so can't really say how different they would feel.
Off course these are not hydraulics with smooth effortlessl pulling, but I can't cay I've ever missed more braking power