Disc Brakes for S40
- Thread starter ElyDave
- Start date
velocio
Austrian roadside steckerlfisch (fish on a stick)
My S40 has the same setup as Cpml123, TRP Spyre SLC's with 160mm rotors front and back. I don't know if that was the stock setup or not, as I bought my S40 secondhand, but I'm starting to think maybe it was ... I have a Bacchetta Giro with BB7's, my only other disk equipped bike, and I have to say the Spyre's are quite a revelation in terms of function and they're lookers as well.
As for rack interference... The rack lower mounting points are 3.5" (just measured) up the "chainstay" (or would it be a "lower seatstay" in this case?) from the center of the rear axle, pretty far away from the brake. I don't see how 160mm vs 140mm rotors would make much, if any, difference. I currently have a front rack mounted back there that's worked out beautifully. It's adjustable for height, so the rack isn't hovering a handful of inches above my 650B tires, it has a top deck for lashing stuff to and, best of all, both low-rider and high-rider positions for panniers. It's this guy: https://www.blackburndesign.com/en/p/outpost-front-world-touring-rack
I'd think that whatever rack you get you'll want one that's adjustable for height, since the lower mount position is quiote a bit higher than typical.
-Jack K.
Raleigh, NC
I noticed the higher mounting point as well - I think I've currently got it mounted omn what would be the mudguard mount point, but it does have level and height adjustment and I think would have sufficient clearance to the seat. I was looking at that point on the rear frame just yesterday thinking about this.
My plan was originally to move the disc brakes from my M5, but that is looking problematic for braking options there with my wheel/fork combination. Those are BB7 Roads, which I'm very happy with in terms of performance and adjustability. I'm not familiar with the TRP fully mechanical options, but the Cable/HYD things are fugly as sin. I did have a look at mechanical disc brakes yesterday on a part site and the TRPs are nearly £20 more expensive, each, here in the UK.
Thinking that one option here might be to carry out a trial run along the lines of
- move rack mountings
- borrow a caliper from the M5 to check rear mounting and clearance with the dynohub (if I can find my 6-bolt to centre lock adapter)
- decide from there onwards.
here's my current rack set up
My plan was originally to move the disc brakes from my M5, but that is looking problematic for braking options there with my wheel/fork combination. Those are BB7 Roads, which I'm very happy with in terms of performance and adjustability. I'm not familiar with the TRP fully mechanical options, but the Cable/HYD things are fugly as sin. I did have a look at mechanical disc brakes yesterday on a part site and the TRPs are nearly £20 more expensive, each, here in the UK.
Thinking that one option here might be to carry out a trial run along the lines of
- move rack mountings
- borrow a caliper from the M5 to check rear mounting and clearance with the dynohub (if I can find my 6-bolt to centre lock adapter)
- decide from there onwards.
here's my current rack set up
super slim
Zen MBB Master
I tried a 140 mm disk with a mechanical Sprye, but my wheel has high flanges, so the spokes just touch the Sprye!!!!
No problems with a 160 mm disk.
I've pushed the button on the BB7 Road S, I already know they work, and I've had a couple of bike mechanics tell me they're better than the Spyres. 160mm rotors come as standard, so we'll see how they fit with the dyno wheel.
The rebuild is progressing, front end now reconstructed - chainstay provided was about 1.5" shorter than previous and the fork steerer is shorter, so I'll have to dial in the cockpit position again. I've had to send a query back to CB though as the seat back they sent wasn't fully drilled and was scratched in several places. I may end up drilling it myself if they give me decent instructions - I've not drilled CF before.
The rebuild is progressing, front end now reconstructed - chainstay provided was about 1.5" shorter than previous and the fork steerer is shorter, so I'll have to dial in the cockpit position again. I've had to send a query back to CB though as the seat back they sent wasn't fully drilled and was scratched in several places. I may end up drilling it myself if they give me decent instructions - I've not drilled CF before.
benphyr
Guru-me-not
velocio
Austrian roadside steckerlfisch (fish on a stick)
Hey ElyDave,
Did the bike mechanics who told you the Avid BB7 Road S were "better than the Spyres" say why they thought that? The one-sided nature of the BB7 design is a disadvantage I find hard to get past, but perhaps the BB7 makes up for that in other ways? BB7's have certainly been around longer (more or less forever in disk brake years), so I'd expect most bike mech's would be very comfortable with them and could, almost, service them with their eyes closed.
Cheers,
-Jack K.
Did the bike mechanics who told you the Avid BB7 Road S were "better than the Spyres" say why they thought that? The one-sided nature of the BB7 design is a disadvantage I find hard to get past, but perhaps the BB7 makes up for that in other ways? BB7's have certainly been around longer (more or less forever in disk brake years), so I'd expect most bike mech's would be very comfortable with them and could, almost, service them with their eyes closed.
Cheers,
-Jack K.
benphyr
Guru-me-not
I've heard two things from mechanics:
-The newer BB7's / BB5's are slightly different from the original ones. BB5's in particular are sometimes complained about being poorer quality than the first ones.
-Secondly, I have heard that the tolerances are exactly the same for the BB7's as for the Spyres and that means that if you have an out of plane disc it may work differently with the Spyres. Different could mean easier to adjust or more forgiving of out of planar disc even if the theory of the mechanism is better for the Spyres. This is what I have heard from two different mechanics that I have used and have significant experience. BB7's would be set up with minimum clearance on the stationary side and minimum clearance on the moving side whereas Spyre would be adjusted to be centred on the rotor. This would, at least in theory, lead me to believe that IF the rotor is absolutely true and adjusted perfectly then Spyre should be a better device however IF there is an imperfection the BB7's could be more forgiving.
Setup and how something functions are told by experience and measurement of actual performance not theory or calculations on paper but just for fun let me make some late night theorizing.
Beware: assumptions below:
-100% means perfect braking power and modulation and is had by squeezing brake pads equally from both sides,
-1 unit clearance required on either side of rotor to pad to prevent rub and have maximum power and modulation,
-each additional unit of clearance decreases brake performance and having to push in an extra unit / bend in the rotor causes -5% braking performance per unit bent (this results in 5% poorer performance by the BB7's in the ideal situation of a perfectly planar rotor and affects both differently for the imperfect rotor as "calculated" below) or to look at it another way - 5% poorer performance per unit of extra clearance,
-balanced clearance is ideal and more clearance on one side than the other results in poorer braking by say 5% per unit extra clearance
True rotor- Spyre winner:
Spyre 100% for 100% of the rotation = 100%
BB7 95% for 100% of rotation = 95% (some loss due to bending rotor being poorer design)
Out of True - 4 units of minimum clearance! BB7 winner:
Spyre 100% perfect for 10% of rotation + 80% for 90% of rotation = 82%
BB7 95% for 90% of rotation + 75% for 10% of rotation = 93% (not counting extra play in brake lever/cable slack)
Another assumption - you can handle the "large" extra clearance required by the out of true rotor. If the out of true impacts having enough braking power you might have to deal with a little rub. The BB7 would rub for 10% of the time at low force, the Spyre would rub either at higher force or for longer part of the rotation.
Well that was fun. As it is 01:00hrs here: To those down below - Afternoon mates! To those in U.K.ness - Top o' the mornin'. And to all, a good night.
-The newer BB7's / BB5's are slightly different from the original ones. BB5's in particular are sometimes complained about being poorer quality than the first ones.
-Secondly, I have heard that the tolerances are exactly the same for the BB7's as for the Spyres and that means that if you have an out of plane disc it may work differently with the Spyres. Different could mean easier to adjust or more forgiving of out of planar disc even if the theory of the mechanism is better for the Spyres. This is what I have heard from two different mechanics that I have used and have significant experience. BB7's would be set up with minimum clearance on the stationary side and minimum clearance on the moving side whereas Spyre would be adjusted to be centred on the rotor. This would, at least in theory, lead me to believe that IF the rotor is absolutely true and adjusted perfectly then Spyre should be a better device however IF there is an imperfection the BB7's could be more forgiving.
Setup and how something functions are told by experience and measurement of actual performance not theory or calculations on paper but just for fun let me make some late night theorizing.
Beware: assumptions below:
-100% means perfect braking power and modulation and is had by squeezing brake pads equally from both sides,
-1 unit clearance required on either side of rotor to pad to prevent rub and have maximum power and modulation,
-each additional unit of clearance decreases brake performance and having to push in an extra unit / bend in the rotor causes -5% braking performance per unit bent (this results in 5% poorer performance by the BB7's in the ideal situation of a perfectly planar rotor and affects both differently for the imperfect rotor as "calculated" below) or to look at it another way - 5% poorer performance per unit of extra clearance,
-balanced clearance is ideal and more clearance on one side than the other results in poorer braking by say 5% per unit extra clearance
True rotor- Spyre winner:
Spyre 100% for 100% of the rotation = 100%
BB7 95% for 100% of rotation = 95% (some loss due to bending rotor being poorer design)
Out of True - 4 units of minimum clearance! BB7 winner:
Spyre 100% perfect for 10% of rotation + 80% for 90% of rotation = 82%
BB7 95% for 90% of rotation + 75% for 10% of rotation = 93% (not counting extra play in brake lever/cable slack)
Another assumption - you can handle the "large" extra clearance required by the out of true rotor. If the out of true impacts having enough braking power you might have to deal with a little rub. The BB7 would rub for 10% of the time at low force, the Spyre would rub either at higher force or for longer part of the rotation.
Well that was fun. As it is 01:00hrs here: To those down below - Afternoon mates! To those in U.K.ness - Top o' the mornin'. And to all, a good night.
a couple of things mentioned,
one being ease of adjustment, which I'm familiar with on the bb7 roads;
others being stopping power as better on the bb7s, though some other users have contradicted that;
robustness of design and longevity, with a suggestion from several places that the TRPs are so poor in environmental resistance that you are better off stripping and rebuilding them before you start;
several people also bemoaning the difficulty in getting replacement pads over here;
easier initial set up on the TRPs.
what it really came down to in the end was, nobody being able to tell me that the TRPs were worth the extra money , and as I'm familiar with the bb7s no reason why not.
one being ease of adjustment, which I'm familiar with on the bb7 roads;
others being stopping power as better on the bb7s, though some other users have contradicted that;
robustness of design and longevity, with a suggestion from several places that the TRPs are so poor in environmental resistance that you are better off stripping and rebuilding them before you start;
several people also bemoaning the difficulty in getting replacement pads over here;
easier initial set up on the TRPs.
what it really came down to in the end was, nobody being able to tell me that the TRPs were worth the extra money , and as I'm familiar with the bb7s no reason why not.
benphyr
Guru-me-not
Thank you for sharing your experience including the stats.
super slim
Zen MBB Master
And they don't squeal like a pig like BB7s when they get wet, with the standard pads!!!
The standard pad life on the Sprye is about 50% more than the BB7s, with a LOT less adjustment!
The Spryes are harder to set up initially, as there is no floating bolt spherical washers!
I will stay with Spryes, on my two Silvios!
The entire bike industry in general has seemed to go TRP for factory bikes. Setup, dual piston design, and maybe some quality/supply issues drove that change as Avids used to reign supreme for disc brakes. Everything is dependent on a lot of other factors like hub flange height, etc as was mentioned for compatibility. I like the TRP's as they have a very narrow profile, which makes routing fender and rack stays simpler with less need for gargantuan spacers and standoffs to clear the caliper.
That said the BB& roads are good - and another of the few good options for road levers.
That said the BB& roads are good - and another of the few good options for road levers.
starting to look like a bike again. Need to buy brake cables tomorrow, add the seat and then ready to go. May need a bit of chain adjustment as the chainstay replacement is shorter than the original. 10sp cassette did not need a spacer, I seem to remember that was a 9/10/11 freehub, all cassettes being the same width. BB7 roads do not give any issues with rack mounting, however they both needed the 20mm adapters, luckily I had one spare as the supplier has them bagged up as "rear" with a 20mm adapter, and "front" with a 0mm adapter. I'd have been OK with a 140mm rotor I think, but, that would have resulted in fouling of the spokes with the dyno-hub by the look of things
@Robert Holler - did you get my e-mail re: the seat holes?
@Robert Holler - did you get my e-mail re: the seat holes?
