2013 will likely be looked at as the year that disc brakes on road bikes became big, all of a sudden a lot of the major manufacturers are coming out with disc braked road bikes. Many different types, proper race bikes, tourers, cyclocross bikes and do-it-all type bikes. Even though the UCI allowed disc brakes in cyclocross competition in June 2010, it's taken quite a while for it to filter down to the consumer level. What makes me wonder is what relevance UCI regulations have on the vast majority of the population, probably less than 1% of the population even races at all under any kind of regulation let alone UCI regulations. It's good however to see a range of road bikes with disc brakes now, as they are certainly the way forward much in the same way as they changed mountain bikes many years ago. They are basically default on mountain bikes now, only the very low end mountain bikes would come with rim brakes nowadays.
As I had chosen to transplant my Campagnolo Athena groupset onto my new bike, the only choice was a cable operated disc. I have owned hydraulic discs in the past on a flat bar bike and am completely aware of their superiority, however at this point in time the only hydraulic discs available would require a complete groupset change to Shimano or SRAM. There are plenty of hybrid designs on the market, like the converter cable-to-hydraulic boxes as well as the TRP Hy/Rd, however these half-way solutions seem a bit like a work around until fully hydraulic systems are more readily available for drop bar bikes.
Currently, the most popular choice for cable discs on road bikes is the Avid BB7, which is a single piston brake which utilises ball bearings in it's mechanism, hence the BB nomenclature. However TRP, the high end division of Tektro recently released the Spyre brake, this brake is unique in that it is the only cable operated dual piston caliper on the market at the moment. Typically, most cable disc brakes are single piston; the way they work is that when the brake is acutated, the moving piston bends the rotor and clamps it inbetween it and the fixed piston. The dual piston design has both pistons moving in at the same time. In theory the dual piston design means you don't waste energy bending the rotor that tiny little bit. The TRP Spyre also is a lot smaller and elegant looking than the Avid BB7 or any of Shimano's calipers. In the previous post where I covered the drivetrain and brakes I touched briefly on the installation of the TRP Spyres.
Installation was straightforward, the calipers came in the box with a 160mm rotor and IS to post mount adaptors for 140mm and 180mm discs. As the front hub I have is a Shimano one, it utilises a centrelock attachment for the rotor, the rotors only came in a 6-bolt fitting so it was either I buy an adaptor or a new rotor. I ended up buying a Shimano XT/Saint RT79 rotor in 180mm size as it was about the same price and it was one of the IceTech rotors which features an aluminium core sandwiched inbetween two layers of steel, this supposedly helps with heat dissipation and less likely hood of fade during heavy braking.
The initial break-in didn't take too long, after about 10-20 hard stops you could quickly feel the power build up. The lever action is quite light, significantly lighter than with rim brakes. Once broken in it was quite easy to lift the back wheel without too much hand pressure. The modulation was quite good, a lot better than rim brakes but not quite to the level of hydraulics as you can still feel the cable flexing under pressure. They stayed very quiet during braking unless some rain or dirt got on the rotor which would cause some squealing until it cleared, this is somewhat normal in my experience with discs. The outboard pad can be adjusted with a 3mm allen key socket hidden within the Torx socket.
Initially I did feel that to have it at the cable adjustment where it didn't rub, it required a little too much lever movement to get full power, the brake lever was almost touching the bar. This was fixed by just truing the rotors and then adjusting the position of the caliper so there was even clearance between the rotor and each piston. The post mount allows very fine adjustment so there is almost no rub, this is assuming your rotors are dead straight. From then on I was able to set the cable so braking came on straight away with no rubbing when it was released.
On the first long ride I took it on, it performed admirably with no hiccups even in mucky conditions. Once bedded in and properly adjusted they had a nice feel, with plenty of power available on tap from little hand pressure. I did ride few a fair bit of loose gravel, leaves and mud and was able to feather the brake quite lightly with these brakes. I gave the bike a good wash after this ride, and came across something slightly odd a few days later. Under hard braking the front caliper would shudder quite regularly, I couldn't figure it out and I cleaned the pads and rotor with methylated spirits which made no difference. Finally I what got rid of the shuddering was a small amount of grease on the back of the pad, what must have been happening was the pad must have been oscillating within the caliper against the piston when they were being braked. The stock pads are meant to be a semi-metallic organic compound, they offer good initial bite and are pretty quiet in the dry. After a muddy ride in Epping forest I noticed that the lever position had moved slightly on the rear brake, probably due to some muck getting on the pads and grinding them down, still this isn't completely unusual for organic pads but slightly disappointing as the amount of braking I did that day wasn't really all that much.
However sadly, only a month after I purchased them and a week before Christmas the Spyre calipers were recalled for a defect. There had only been one incident where the ball bearings in the mechanism could come loose when the brake was used where there were none or very worn pads. I returned them in early January and received a replacement set a week later, which was a lot earlier than I expected as I had read that the stock of the revised version wouldn't be available till late January. Waiting a whole month for replacement brakes... no thanks!
The revised version came with some free cables and compressionless housing, something the originals did not which was a nice touch. The calipers themselves were also slightly different, the revised version has adjustable pistons on both sides, they are now marked accordingly compared to the previous version which just had a Torx socket on one side. This simplifies getting the rotor centred correctly even more so than before and saves you the faff of fiddling with the post mount bolts. I can't say there is any notable difference in feel with the revised version, definitely it's peace of mind knowing they don't have the defect of the old one.
Overall I really like these brakes, they have gobs of power on tap with a very light lever feel. They are easy to adjust and centre and best of all they are smaller and lighter than the current market leader for cable disc brakes, the Avid BB7. They have a very low profile and sit mostly within the frame which reduces any chance of interference with racks, panniers or heels. They look great and are reasonably priced as well at £60 per caliper which includes the disc and adaptors. There is a premium version which has a carbon fibre lever which is significantly more at £80/caliper for a negligible 8g weight saving. I still am yet to ride these on fast long alpine descents which require heavy braking around switchbacks, but come summer I'll probably do this. For now, I really like these brakes and I'd probably say they are probably the best cable disc for road bikes on the market right now. A more long term review to come, thanks for reading.