Crossbikes- Let’s talk brakes

[bluerider]

I took off Avid Shorty 6s and installed Avid Ultimates on my Blue Norcross EX. Love them. Mega power, easy modulation, and great adjustability. They were a huge upgrade over the original brakes. They can also be setup wide for mud clearance or narrow for power. TRP and Paul make nice cantis for cross bikes as well. But for the price Avid Ultimates can’t be beat in my opinion.

[GuyContinental]

@jopamora 23288 wrote:

Dude, did you buy this bike?

Nope- a black 57 with a known history.

[GuyContinental]

Thanks for all of the thoughts!

As V1.1 I replaced the utterly dead v-brake inserts on the rear Shorty’s with Kool Stop Salmons, reduced the wheel clearance a bit/tuned the brakes and ordered the Paul MiniMoto (Paul stuff always tickles my bike-bling nerve which put them over the line vs the Avid Ultimates). If that doesn’t work over a few hundred miles, I’ll probably go with a mullet using an Avid BB5 mechanical, a new fork, rebuilt wheel and then put the Paul on the rear.

I meant to take it out this morning for my new-found mid-commute LFP romp but woke up with some toddler-vector inspired cough… sigh

FWIW I can’t figure out the physics behind Dirt’s note on the small tire surface area and disc brakes (but if anyone would know I assume that he would)- assuming two equally grabby brakes (set for power not modulation) braking from the hub (i.e. disc) is going to add modulation through the spokes and tire lugs whereas braking from the rim essentially limits that system modulation to the tire… thus, you should have more skidding from a rim brake than a disc. I’ve ridden narrow tires (2.1, so only 18mm wider than my CX tires) on my various disc-equipped mountain bikes from time to time at pretty high speed (albeit probably not as fast as Dirt…) and have never noticed a particular propensity to skid provided that I wasn’t locking up the brakes.

[OneEighth]

+1 for most things Paul.
Why not go with the Neo-Retro? I would expect they would honk a lot better.
Also BBB pads are lovely.

[jabberwocky]

@GuyContinental 23372 wrote:

If that doesn’t work over a few hundred miles, I’ll probably go with a mullet using an Avid BB5 mechanical, a new fork, rebuilt wheel and then put the Paul on the rear.

If you do end up going this route, spring for BB7s. They are different brakes, and the BB7s are not much more expensive and much better.

@GuyContinental 23372 wrote:

FWIW I can’t figure out the physics behind Dirt’s note on the small tire surface area and disc brakes (but if anyone would know I assume that he would)- assuming two equally grabby brakes (set for power not modulation) braking from the hub (i.e. disc) is going to add modulation through the spokes and tire lugs whereas braking from the rim essentially limits that system modulation to the tire… thus, you should have more skidding from a rim brake than a disc. I’ve ridden narrow tires (2.1, so only 18mm wider than my CX tires) on my various disc-equipped mountain bikes from time to time at pretty high speed (albeit probably not as fast as Dirt…) and have never noticed a particular propensity to skid provided that I wasn’t locking up the brakes.

I have a CX bike with discs and have never had any issues overwhelming the tires. Honestly, I don’t think road mech discs are that much more powerful than good rim brakes, they are just more consistent (and in the case of cantis, less bitchy to adjust).

[TwoWheelsDC]

@bluerider 23289 wrote:

I took off Avid Shorty 6s and installed Avid Ultimates on my Blue Norcross EX. Love them. Mega power, easy modulation, and great adjustability. They were a huge upgrade over the original brakes. They can also be setup wide for mud clearance or narrow for power. TRP and Paul make nice cantis for cross bikes as well. But for the price Avid Ultimates can’t be beat in my opinion.

Oh man, those look sweet. I’m definitely going to look at those as the next upgrade to my commuter. I like the skinny-ish tires too. Mine has 32 semi-knobbies on it now and I’m considering going to more sporty 28s.

[GuyContinental]

Quick follow-up on this project- quite simply the front Paul brakes plus Kool Stop pads rule. The bike stops NOW with no stutter.

I took the bike on some technical trails in Rhode Island last week (think yellow loop at Gambril) and had no problem stopping (to portage…) before pitching off the 6′-10′ chutes. Taking the CX on real MTB trails was a heck of a lot of fun- it was absolutely not the right bike for the trail (7″ of travel and a FS would have been nice) but I had loads of fun in really unexpected ways- the CX required a LOT of riding strategy in both technical climbs and descents. I look forward to taking it out locally- it should be a nice equalizer when riding with my wife (I’ll be either walking or bleeding on the ground).
[ATTACH=CONFIG]1336[/ATTACH]- noop, I walked this one, probably would have on any bike. Easily a 10′ drop

[ATTACH=CONFIG]1337[/ATTACH]- I at least tried this- it laughed at me and spit me out.

[GuyContinental]

Second follow up for those pursuing CX brake knowledge… for those of you that actually know what you are doing on a cross bike, you will laugh at this but I come from 18+ years mountain biking so much of this did not immediately come to mind. After 600 miles (maybe 200 on dirt- some of it very technical) these are some of my observations…

You have (essentially) three possible braking positions on a cross bike:

Hoods– lowest brake power, good for climbing, nearly impossible to both hold on and brake, also tough to get the ft wheel off the ground- you can wrap your fingers and scrub some speed with your index fingers but stopping isn’t really going to happen. Alternatively, you can hold on by pinching thumb and index fingers leaving four fingers for the brake- this will stop you but good luck holding on unless you have monster hand strength

Drops– good brake power, very fast, rough to transition out of and hard as heck on the body. I call this the Danger Squirrel posture because your head is basically over the front wheel and with an aggressive set up you are verrry low and verrry forward. For awhile I was riding this way exclusively when heading downhill- it was great- I could brake (and stop), I could hold on, I could even climb. However, roots and technical sections really hurt and I was always theees close to pitching over the bars. Also, steep downhill gravel is really bad news when your weight is all the way forward…

Bar Tops with interrupter levers– great braking power, MTB handling, better front wheel lift but not so great climbing and not extremely fast. Superior for getting over logs or through major technical sections.

I added the interrupters over the w/e and I am now a happy camper- Hoods for climbing/cruising; Drops for Danger Squirrel fast; Bar tops for most descending and technical riding. I still have a long way to go on the learning curve (I bleed a lot) but I have a ton more confidence in braking now that I have decent equipment and some real tools in my technique.

[TwoWheelsDC]

@GuyContinental 28110 wrote:

Bar Tops with interrupter levers– great braking power, MTB handling, better front wheel lift but not so great climbing and not extremely fast. Superior for getting over logs or through major technical sections.

I added the interrupters over the w/e and I am now a happy camper- Hoods for climbing/cruising; Drops for Danger Squirrel fast; Bar tops for most descending and technical riding. I still have a long way to go on the learning curve (I bleed a lot) but I have a ton more confidence in braking now that I have decent equipment and some real tools in my technique.

I really like having these on my CX bike, even if I don’t use it for actual CX…but for commuting in traffic, or cutting from MUPs/sidewalks to grass or gravel, I really like the stability of having my hands on the top bar with brake levers right there. It’s like having the urban handling benefits of a flat-bar, but with the added hand positions of drop bars. Oddly, I don’t miss them at all when I’m on my road bike, but that thing stops sooooo much better than my CX bike, so I can stop just as fast, if not faster, on the hoods of my road bike than I can with the cross-levers on my commuter. But I have seen a few new steel road bikes with top levers, but I don’t think we’ll be seeing them trend on AL and Crabon bikes any time soon.

[GB]

Question about interchangeable wheeles from my MTB to my hypothetical CX bike.

I have a MTB with disc brakes. I’m looking at a XC frame. What needs to be the same in order to swap my wheels out? I’m guessing disc size needs to be the same. I’m guessing that impacts caliper location. Does that impact disc brake mounts/frame?

If I have the best setup, what will I need to adjust when switching wheels?

If you were going to pick 1 disc size to go between MTB and CX what would it be?

Thanks

[Phatboing]

@GB 114662 wrote:

Question about interchangeable wheeles from my MTB to my hypothetical CX bike.

I have a MTB with disc brakes. I’m looking at a XC frame. What needs to be the same in order to swap my wheels out? I’m guessing disc size needs to be the same. I’m guessing that impacts caliper location. Does that impact disc brake mounts/frame?

If I have the best setup, what will I need to adjust when switching wheels?

If you were going to pick 1 disc size to go between MTB and CX what would it be?

Thanks

1. The disc size depends on the frame/fork design – my Colossal can take a 160mm disc on the fork, but only 140mm rear on ze frame.
2. Someone else will have to answer that – I have no idea. My guess is you shouldn’t have to adjust stuff if you’ve set up both bikes right.
3. 160mm. Stop good.

[jabberwocky]

You may have to adjust the caliper each time you swap wheels. Disc hubs and rotors are all slightly different. Whereas wheel one is perfectly aligned, wheel two might rub (which is why the calipers have the ability to shift around a bit).

[hozn]

You can get little shim washers to get the rotors to be as identically spaced as possible. AFAIK @vvill has done this. In a perfect world you build with the same hubs, but even that is not guaranteed to mean consistent rotor spacing. Rotors warp, so you have to be willing to periodically re-true them (not that hard with a crescent wrench or the Park Tool). Also even same hubs might be a fraction of a mm different, though typically you can find a middleground pad position that works. On my previous wheelset, I knew when swapping wheels that I would have to adjust — e.g. one click on the inboard pad and 3 clicks on the outboard (Avid BB7), so it only took a few seconds to do that. My wheels now (built with same hubs) can be interchanged without any adjustment — which is good, since my Spyre brakes don’t have indexed pad adjustment. It is only the front fork (with the larger rotor) that I have ever had to adjust.

I am curious about the re-centering of hydro brakes; if the rotors fit within the caliper will the auto-centering take care of small (e.g. 1mm) differences in rotor position? (@jabberwocky?)

As for size, I would choose 160/160 by default, though I am running 160/140 on my CX and road bikes and it works just fine. As hinted above, I suspect that the bigger the rotor, the more likely you’re going to have to adjust your calipers when swapping wheels. I definitely wouldn’t go larger than 160.

[jabberwocky]

@hozn 114697 wrote:

I am curious about the re-centering of hydro brakes; if the rotors fit within the caliper will the auto-centering take care of small (e.g. 1mm) differences in rotor position? (@jabberwocky?)

I’m honestly not sure about that; I have lots of bikes and lots of hydraulic brakes, but zero experience swapping wheels between them. For alignment I tend to just loosen the caliper bolts slightly, squeeze the lever, retighten the bolts (with the lever held) and that works to center it pretty well.

I will say that different brands/models run at different distances from the rotor. My older Avids seem to be pretty generous. My formulas run the pads much closer to the rotor and would probably be much more sensitive to tiny changes between wheels.

[vvill]

@hozn 114697 wrote:

You can get little shim washers to get the rotors to be as identically spaced as possible. AFAIK @vvill has done this.

Yeah I have. It was a pain to set it up, and I still need to do some adjustments when I switch wheels. If rotors were all identical and stayed identical I guess this method could work. Also, this only works for 6 bolt/ISO not Shimano Centerlock hubs.

FWIW I have the Syntace shims not the the Wheels Mfg ones (which come as 20 separate 0.2 shims – one per rotor bolt! So you can get 0.6mm max from one pack with 2 left over. Really stupid for $15 MSRP.) The Syntace are one piece bags of 8 (so up to 1.2mm in a bag) which is much more convenient considering I have 4+ shims on some of my wheels.

I would also choose 160/160 but have 160/140 due to how my bike was built. I think most CX/road frames will handle both those sizes.

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