Anybody using a disc brake on the front wheel of new V20?
- Thread starter unc99
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BentAero
Well-Known Member
I have a 160mm rotor on the
I have a 160mm rotor on the drive wheel. I don't know if a 180 would fit, I doubt it.
Industry Nine Ultralight CX wheels, 135mm drive, 100mm 'rear'.
FYI: The hub on the I-9 non-drive (traditional front) wheel spaces the rotor farther 'out' than other wheels. As such, the rotor (140mm) rubbed on the frame. I had to grind the weld down on the frame for the rotor to clear. The weld was rather 'generous' right where the rotor needed to sit.
The end-view photo is shown with a thick flat-washer between the frame and hub. (since removed) Sure wish I had test-fit the wheels/rotors before powdercoating... Fortunately, my coating guy was able to fix it.
I have a 160mm rotor on the drive wheel. I don't know if a 180 would fit, I doubt it.
Industry Nine Ultralight CX wheels, 135mm drive, 100mm 'rear'.
FYI: The hub on the I-9 non-drive (traditional front) wheel spaces the rotor farther 'out' than other wheels. As such, the rotor (140mm) rubbed on the frame. I had to grind the weld down on the frame for the rotor to clear. The weld was rather 'generous' right where the rotor needed to sit.
The end-view photo is shown with a thick flat-washer between the frame and hub. (since removed) Sure wish I had test-fit the wheels/rotors before powdercoating... Fortunately, my coating guy was able to fix it.
Personally I would go with
Personally I would go with the smaller rotors front and rear. These bikes already have amazing stopping power and even a 160 up front is a lot of brake.
A 180 will not likely fit at all and would be waaaay too much brake.
Robert
Personally I would go with the smaller rotors front and rear. These bikes already have amazing stopping power and even a 160 up front is a lot of brake.
A 180 will not likely fit at all and would be waaaay too much brake.
Robert
ratz
Wielder of the Rubber Mallet
Should be fine for light riders
Weight and speed would be your guide there. If you aren't doing alpine descents and are sub 200 lbs then a 140 upfront is probably just fine. If you are going to "glaze" the disc from over braking I don't think you'd be any more likely to do it to a 140 than you would a 160. However if I was going to put a 140 on the front; I'd strong consider using a TRP HY/RD brake. That's hydraulic but CABLE actuated the cylinder in the brake not the brake lever. The extra control from the hydro should improve the efficiency of the 140 disc and get you a really nice solution. Since the HY/RD comes with the rotor and works with regular brifters it's a good deal at $149.
Weight and speed would be your guide there. If you aren't doing alpine descents and are sub 200 lbs then a 140 upfront is probably just fine. If you are going to "glaze" the disc from over braking I don't think you'd be any more likely to do it to a 140 than you would a 160. However if I was going to put a 140 on the front; I'd strong consider using a TRP HY/RD brake. That's hydraulic but CABLE actuated the cylinder in the brake not the brake lever. The extra control from the hydro should improve the efficiency of the 140 disc and get you a really nice solution. Since the HY/RD comes with the rotor and works with regular brifters it's a good deal at $149.
Rampa
Guru
Careful with smaller discs and hydro! They get HOT!
There are horror stories of people boiling their hydro fluid because they just did not get enough cooling on the disc. I know some discs have additional cooling fins inboard from the breaking surface.
Is the cylinder larger being on the caliper? More fluid will run cooler as well.
There are horror stories of people boiling their hydro fluid because they just did not get enough cooling on the disc. I know some discs have additional cooling fins inboard from the breaking surface.
Is the cylinder larger being on the caliper? More fluid will run cooler as well.
ratz
Wielder of the Rubber Mallet
Trust the science not the stories.
Yeah I'm not much on horror stories; documentation and photos seem to be limited on those fronts for post debug units. The manufacturers test the heck out of this stuff; boiling would be one of the main things they'd be testing for. I would suspect that with the disclaimer I added "not 200lbs" and not doing "alpine descents" you'd be fine. If someone is boiling their brake fluid; then they are likely using it as a "drag brake" which really is the least efficient way to us a bike brake.
I have TRP HY/RD going on a Quest that frequently weighs in at 400lbs; bike+rider+trailer+2 kids+supplies. I'll be able to tell you about the size of the cylinder in a week or two. Because of the high weight I have 160 front and 140 back.
In the end you know your habits. So you'd have to make the call about which will work with your riding style.
Yeah I'm not much on horror stories; documentation and photos seem to be limited on those fronts for post debug units. The manufacturers test the heck out of this stuff; boiling would be one of the main things they'd be testing for. I would suspect that with the disclaimer I added "not 200lbs" and not doing "alpine descents" you'd be fine. If someone is boiling their brake fluid; then they are likely using it as a "drag brake" which really is the least efficient way to us a bike brake.
I have TRP HY/RD going on a Quest that frequently weighs in at 400lbs; bike+rider+trailer+2 kids+supplies. I'll be able to tell you about the size of the cylinder in a week or two. Because of the high weight I have 160 front and 140 back.
In the end you know your habits. So you'd have to make the call about which will work with your riding style.
The TRP hybrids are nice. Way
The TRP hybrids are nice. Way easier to work on than a full hydraulic setup. I have run 140's up front without issues and unless you are doing huge alpine downhills that is still a lot of brake. Last year we were descending Ht. Hood and a front caliper was fine. I am 190 so not a lightweight. ;-)
Robert
The TRP hybrids are nice. Way easier to work on than a full hydraulic setup. I have run 140's up front without issues and unless you are doing huge alpine downhills that is still a lot of brake. Last year we were descending Ht. Hood and a front caliper was fine. I am 190 so not a lightweight. ;-)
Robert
BentAero
Well-Known Member
Though a bit dated, still
Though a bit dated, still good info...
http://www.bikeradar.com/us/gear/category/components/brake-calipers/product/review-trp-hy-rd-cable-hydraulic-road-disc-brakes-47188/
The 160 rotor is only 23 grams heavier than the 140. I'll take the extra stopping power of the 160 every time.
Though a bit dated, still good info...
http://www.bikeradar.com/us/gear/category/components/brake-calipers/product/review-trp-hy-rd-cable-hydraulic-road-disc-brakes-47188/
The 160 rotor is only 23 grams heavier than the 140. I'll take the extra stopping power of the 160 every time.
ccooper
Active Member
Front brake only
Would it make any sense to install a front disc brake only? While I now take more care in trying to lighten up my usage of the rear brake, several years ago I did take a bad fall on my DF when descending because I locked up the rear wheel. If the front brake is enough to stop, is it really necessary to have a rear brake at all?
Chris
Would it make any sense to install a front disc brake only? While I now take more care in trying to lighten up my usage of the rear brake, several years ago I did take a bad fall on my DF when descending because I locked up the rear wheel. If the front brake is enough to stop, is it really necessary to have a rear brake at all?
Chris
Charles.Plager
Recumbent Quant
The problem with disc front
The problem with disc front caliper back brakes is how different the two brakes feel. If you can overcome that (and it shouldn't be too hard), it's not completely crazy.
And having a 160 up front is almost certainly worth the weight penalty.
The problem with disc front caliper back brakes is how different the two brakes feel. If you can overcome that (and it shouldn't be too hard), it's not completely crazy.
And having a 160 up front is almost certainly worth the weight penalty.
I'm setting up to build a V20 and was asking myself this exact question. At this point, has anybody tried a front disk only on a V20?
John Dorlon
Guru
One drawback of only having one brake is that means that you always have to do your braking with the same hand. It's also committing to never (or almost never) let go with your left hand. Imagine getting an itch on your left leg, or you just want to let go of the bar and stretch your left hand a bit, and then a deer runs out in front of you, or the guy in front of brakes for some reason.
It just doesn't seem worth the weight savings to skip the rear brake to me.
ratz
Wielder of the Rubber Mallet
We general like our community members to be around for awhile. The reason for a rear brake are:
1) If you are riding on a Slippery surface; it's wise to use the rear brake only.
2) Approaching sharp bumps; use the the rear brake to cut speed. (Front brake + sharp force to front wheel can taco you or your wheel)
3) Front flat, if the front goes airless; braking in the rear is way safer and likely to keep you upright
4) Front break failure on a hill
5) Brake over heating on long descents (need to alternate between two brakes).
6) if the front is worth of a disc brake the rear probably is too; don't mix them it's going to mess with your brain and cause some sort of wrong human input to happen in a crisis.
RojoRacing
Donut Powered Wise-guy
For me is wouldn't work, in fact my last big mountain race had me wanting 180mm up front. For most my riding which tends to be extreme by recumbent standard the 160mm is plenty so I don't see why a 140 wouldn't work for 95% of CruzBike owners. Rotors aren't very expensive so don't be scared to try small and if you find it making then $40 will get you the next size up.
