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Road disk vs. mountain disk performance?

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Road disk vs. mountain disk performance?

Old 09-17-18, 04:24 AM
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3speed
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Road disk vs. mountain disk performance?

I had BB7 mtn brakes on my old mountain bike. I now have the road version on my touring bike. Both brake calipers and levers are matched to the correct versions(road vs. mtn). The brakes on my old mountain bike were awesome. You could easily put yourself over the handlebars if you wanted to, but they werenít grabby. They modulated well. The brakes on my touring bike donít have nearly as much stopping power. I have a fairly strong grip, and if I make an emergency stop, I have to squeeze the lever pretty hard. The lever feel isnít nearly as good as the mountain brakes. If I lean back, no matter now tight I squeeze I doubt I could send the bike over the handlebars, and wouldnít be able to lock the wheel on pavement. I have a full length housing and had new pads when I installed the brakes. Is there something going on here that I just donít know of due to lack of mechanic experience, or are the road version of the BB7 not as strong as the mountain version?
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Old 09-17-18, 05:13 AM
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What levers are you using? What size rotors? Have the pads been bedded in?
Rotor size makes a huge difference, so if your bikes have different rotors that will explain a lot. Shimano and SRAM have different brake cable pull as well.
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Old 09-17-18, 06:12 AM
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Pads. Change them... the stock ones that come with the calipers suck. If that doesn't make enough difference then next thing after that is to change to something like the Jagwire Pro cables
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Old 09-17-18, 06:15 AM
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Are you comparing the brakring with the hands on the drops? That's the point from you can apply the maximum lever and force.

From the hoods all road brakes (at least mechanical) are quite mediocre
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Old 09-17-18, 08:34 AM
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Internal caliper differences

One piece inside the BB7 MTN, vs BB7 Road that is different, between them,
is a crown shaped ring with ramps that turns a cable arm pulling it around
into the force pushing the pad into the disc.
(That is what the tiny internal ball bearings ride against, is those ramps)
with a longer cable pull the rise-rate of those ramps is less
than the steeper rate needed when the cable pull available is less..

OP not happy with BB7 Road , may want to change their brake calipers
..TRP Spyre is their double acting short pull mechanical .. Spyke long pull..







....

Last edited by fietsbob; 09-17-18 at 09:55 AM.
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Old 09-17-18, 08:44 AM
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I have found the exact same thing (to a lesser extent). I like the road bb7s, but they are not as powerful or solid feeling as the mtb version. This is using compressionless brake housing (Jagwire) on both.

I think the reason is the cable pull ratio. With the lower amount of cable pull on the road versions (to match the road levers) means there is higher tension on the cables, which means more flex in the lines, which means mushier braking.

If you are not already running compressionless brake housing, I would suggest doing so. I makes a difference.
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Old 09-17-18, 09:48 AM
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Fwiw,

I'm removing the BB7 M in favor of TRP HyRd , a cable pulled hydraulic..
this winter, rainy season.

Having more cable pull than the brake caliper needs works out fine ,
Avid Speed Dial lever, dial, lets that be another adjustment..

pad wear compensation goes automatic, but as with hydraulic discs, norm,
Keeper needs using in caliper, when wheel is out..
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Old 09-17-18, 01:37 PM
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Levers on the touring bike are Tektro and rotors on both bikes are stock 160mm that come with BB7s.

I donít have compressionless housing. Iíll try swapping that out and getting new pads. Thanks guys.
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Old 09-18-18, 08:44 AM
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Originally Posted by 3speed View Post
Levers on the touring bike are Tektro and rotors on both bikes are stock 160mm that come with BB7s.

I donít have compressionless housing. Iíll try swapping that out and getting new pads. Thanks guys.
And the Spyre/Spykes feel much better to me than the BB7.
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Old 09-18-18, 11:15 AM
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Originally Posted by Trevtassie View Post
And the Spyre/Spykes feel much better to me than the BB7.
I have really wanted to try the Spykes or the Spyres.

I went with bb7s on my road/gravel bike because I had used the mtb version for 15 years on various mtbs and always liked them a lot. It was not until after I built the bike that I realized what the difference with the Spyres was. In retrospect I might have coughed up the coin for the Spyres.
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Old 09-18-18, 03:21 PM
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Originally Posted by Kapusta View Post
I have really wanted to try the Spykes or the Spyres.

I went with bb7s on my road/gravel bike because I had used the mtb version for 15 years on various mtbs and always liked them a lot. It was not until after I built the bike that I realized what the difference with the Spyres was. In retrospect I might have coughed up the coin for the Spyres.
Have a look on Aliexpress. I got a pair (F&R) of Spykes with 180mm slotted discs for around US$100. The supplied pads sucked, but everything else seemed good, i.e. not fakes... just OEM in plastic bags. They also need a good service to grease up the anti binding ball races fairly early on, but that applies to all TRP mechanical calipers.. There are a couple of how to-s on google.
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