Road Bike, Cycling Forums banner

1 - 20 of 30 Posts

·
Registered
Joined
·
356 Posts
Discussion Starter #1 (Edited)
I've been experimenting with mini-V's on my bike and I thought I'd share what I've found. In my experience, they're generally easier to deal with than cantilever brakes, but not necessarily better in every respect. These are my experiences -- YMMV.

I have some very short brakes (80mm) and some slightly short ones (95mm). For comparison, Shimano V-brakes are 107mm and "standard" Tektro V-brakes are 102mm.

Pro:
- Very cheap.
- No squeal or shudder.
- Simpler to set up, especially in the front.
- No need for cable hangers and related cable routing issues.
- Did I mention no squeal or shudder?

Con:
- Quick release can be difficult. (see below)
- No cable adjustment. (see below)
- On some bikes, might not leave enough clearance for fenders.

The quick release issue isn't really a problem if you use Campagnolo levers, which have a QR on the brake lever. Also, if you get noodles with barrel adjusters, or have inline cross levers with adjusters, they can help give you the necessary clearance. Finally, you can file down the end of the noodle so that you don't need to pull it as far to release the brake.

One important factor to pay attention to is the vertical distance between the brake posts and the rim. ("Vertical" isn't exactly vertical, but rather measured along the length of a v-brake arm.)

In the first three pictures, the distance is approximately 29 or 30mm, measured center of post to middle of braking surface. The brake in these pictures have 80mm arms, resulting in a mechanical advantage of about 2.66. I find that this gives me good braking power (better than the cantis I had) and even with a 32mm tire, there's plenty of mud clearance (see pictures 7 and 8). They also have plenty of clearance to the rim (see pictures 5 and 6). Using brakes with longer arms will result in more braking power but less rim clearance.

On the rear of one of my bikes, the vertical distance is about 38mm. You can see this in the fourth picture below, where the brake pads are set to the highest possible position. When I had cantilevers on here, the back brake was almost useless because, in addition to the somewhat low mechanical advantage of that brake design (Avid Shorty), the higher pad position resulted in even lower MA -- that is, more travel and less force (also, a firm brake feel at the lever). When the post-to-rim distance is greater, you need a longer arm to clear large tires. In this case, I'm using 95mm arms, which gives a MA of 2.5, similar to the others. If I used 80mm arms, there would be less vertical tire clearance, but the MA would be greater, at 2.1, resulting in more rim clearance and less power.

I've heard others say that tire clearance is an issue, but it hasn't been for me. Even the very short 80mm arms leave plenty of space for the tire -- slightly more than the fork crown shown in the pictures with fat tires.

I think that one of the reasons that there's more braking power is not just mechanical advantage -- it's also that there's less flex in the entire system when you brake, compared to cantilevers. And I think the reason there's no shudder or squeal is because there isn't the feedback loop where the arms and/or hanger flex and pull the cable a little tighter, increasing the pressure and friction on the rim, and then once the arms get pulled far enough, the pads let the rim slip and this cycle gets repeated.

If you find that you want more or less mechanical advantage, the thing to do is get a brake with different length arms. Fortunately, they're very cheap. I paid between $9 and $13 a set, so for the price of a single Paul brake, I can equip about four whole bikes!

I made a list of different brake lengths, using information from the Tektro web site (which seems to be down right now). There may be others, but this is just what I found:
- 75mm: 917A
- 80mm: 926AL
- 85mm: BX3V, BX1V, RX1, RX3, RX5
- 90mm: RX6 (this seems to have a special quick release; it might solve the QR issues)
- 95mm: BX25, 930AL, BX310, 918AL
- 102mm: Tektro "standard" V-brakes
- 107mm: Shimano V-brakes
- 110mm: Tektro "long" V-brakes

If you're thinking about getting mini-V's, try measuring the post-to-rim distance (although this isn't easy), then multiply by the desired mechanical advantage to get the arm length. As I mentioned earlier, MA=2.5 to 2.6 gave me good power and adequate rim clearance. In my case, 2.6 x 30mm = 78mm, so 80mm arms worked. Or you can just buy a whole bunch and see what works!


A side note: I gather that Shimano's new Dura-Ace 7900 levers pull more cable than their previous models, so maybe these and other future Shimano STI levers will allow for longer V-brakes with more clearance...
 

·
elmar
Joined
·
265 Posts
here is my experience.
if you work with adjustable noodles ,cable adjustment and wheel change are easy.
i ride mini-v since 3 years now. (15-20 crossraces, 10-15 roadraces)
in germany it is nearly standard now , to use mini-v.

more pros .
even cheap brake pads work .
superlight brakes possible ,my tuned rx 5 are 116 gramm. My tuned avid are 101 gramm !
-v-brakes are much faster modulated and very easy to set up . toe- in is possible ,( canti like frogglegs are not possible to be toed-in .
without special brakepadholders or a knife ....)
disadvantages of mini-v
-cables need to run fine .
- a little less mud clearance than Shimano or avid cantilever.

the parts of the the low cost tektros are identical-similar to cane -creek and avid , because they are all built there ,too.so if you need spare parts or tuning kits ............................,
the strongest springs are on tektor rx 5.
Best length seems to be 85 mm .
i have been riding campagnolo .too. but there springs are not so strong .
they are nicer in their finish .brakepads for them are super expensive in germany .
they have an own standard for the pads .
 

·
Game on, b*tches!
Joined
·
13,467 Posts
Looks like it would be fine, as long as you don't race them in mud. My Tektro Canti's were quite easy to set up and they have a huge amount of clearance.
 

·
Registered
Joined
·
356 Posts
Discussion Starter #5
elmar schrauth said:
superlight brakes possible ,my tuned rx 5 are 116 gramm. My tuned avid are 101 gramm !

the parts of the the low cost tektros are identical-similar to cane -creek and avid , because they are all built there ,too.so if you need spare parts or tuning kits ............................,
Thanks, Elmar... I have a couple questions:

What did you do to reduce the weight so much?

Also, what kind of Cane Creek and Avid brakes are you referring to?
 

·
A wheelist
Joined
·
11,322 Posts
Yes I agree that the Tektro mini-v is a great brake especially for the money (<<$14>>).

Mine was easy to set up, it's dead quiet and it doesn't make my carbon fork shudder, which is what probably would happen, I was assured, if I fitted a front cantilever.

The only downside would be the closeness of the cable to the tire for cyclocross (9/16" on my bike) but as I don't race CX and rarely ride in really crappy conditions, it's not an issue.

With the Travel Agent, the cable pull with STI levers (Ultegras in my case) is fine and I got the model with the built-in adjuster. I left the rubber cable bellows off on purpose.

Edit - for those with eagle-eyes, those mounting stud bolts aren't standard Tektro issue. I have a small stash of high-quality aluminum brake post bolts. Think of the weight I save!!
 

·
Registered
Joined
·
56 Posts
Mike T. said:
With the Travel Agent, the cable pull with STI levers (Ultegras in my case) is fine and I got the model with the built-in adjuster. I left the rubber cable bellows off on purpose.
QUOTE]
Isn't the idea of the mini Vs that they are compatible with road levers without a travel agent?
 

·
A wheelist
Joined
·
11,322 Posts
MCBR1 said:
Isn't the idea of the mini Vs that they are compatible with road levers without a travel agent?
Not that I was ever aware of and looking at my own setup, without the TA, the pads would have to be very close to the rim - which doesn't seem like a good idea when using these brakes for their intended purpose - dirty conditions riding.

Edit - from the Bikeman.com website - "Problem Solvers Travel Agent: Allows use of non-linear pull brake lever with any linear pull brake. Great for touring or cyclocross aplications with road STI or Ergo levers."
 

·
Registered
Joined
·
356 Posts
Discussion Starter #9
MCBR1 said:
Isn't the idea of the mini Vs that they are compatible with road levers without a travel agent?
FWIW, I didn't use travel agents in my setup pictured above, and I'm using Campagnolo ergo levers, which I think pull the same amount of cable as Shimano. You can see the brake clearance in some of the pictures.
 

·
Registered
Joined
·
337 Posts
I also ran the mini-v's with Campy ergo levers on my cross bike. I've since gone back to canti's, because I couldn't get the mini's to modulate as well as canti's. They were either on or off.

I am now using the mini's on a singlespeed "monster cross" bike with 287v levers, designed for v's, and the feel and performance is much better.
 

·
NeoRetroGrouch
Joined
·
6,491 Posts
MCBR1 said:
Isn't the idea of the mini Vs that they are compatible with road levers without a travel agent?
Yes, you don't need them. If you're going to use the Travel Agent, then you can use std Vs and get a lot more clearance above the tire. - TF
 

·
elmar
Joined
·
265 Posts
winstonc said:
Thanks, Elmar... I have a couple questions:

What did you do to reduce the weight so much?

Also, what kind of Cane Creek and Avid brakes are you referring to?


i changed all bolts and nuts , and the brakeshoes(KCNC) .
the inner parts (bushings ) from steel to alloy .(avid tuningkits from sl brake )

my lightest brake is an avid mtb brake ( magnesium ) which i cut to 85 mm .
when i will get titanum sprngs it wll be sub 100 gramm (including brakeshoes-pads)


the bushngs of all tekro rx 5, avid shorty,cane-creek scx5, avid mtb v-brakes seem to be the same .

a very big advantage of mini-v is ,that you dont have to change brakepads ,when changing rims from alloy to carbon .
 

·
elmar
Joined
·
265 Posts
Kram said:
Looks like it would be fine, as long as you don't race them in mud. My Tektro Canti's were quite easy to set up and they have a huge amount of clearance.

i race 15-20 races /season .
since 3 years now.
no bigger mud problems than the others .
no mor big changing than the others .


first ride ,then write
 

·
Number 2 on the course.
Joined
·
4,405 Posts
TurboTurtle said:
Yes, you don't need them. If you're going to use the Travel Agent, then you can use std Vs and get a lot more clearance above the tire. - TF
Tektro makes short-pull V-brakes. I don't see how running a brake with lesser clearance combined with Travel Agents is an attractive option.

It doesn't sound like Mini-Vs are a solution to fork shudder anyway:

samuel said:
By the way did I mention how much I disliked the Mini V brakes!! Oh yea how about the fork brake chatter.

http://forums.roadbikereview.com/showpost.php?p=1748999&postcount=15
 

·
NeoRetroGrouch
Joined
·
6,491 Posts
PeanutButterBreath said:
Tektro makes short-pull V-brakes. I don't see how running a brake with lesser clearance combined with Travel Agents is an attractive option.

It doesn't sound like Mini-Vs are a solution to fork shudder anyway:
The length of the pull is determined by the length of the caliper. If they are short pull, they are mini. - TF
 

·
Number 2 on the course.
Joined
·
4,405 Posts

·
eat live sleep cross
Joined
·
414 Posts
i dug out my old first gen mini-Vs and they were fine for a while with flat bar brakes (old school ones)... but absolutely horrid with the STI Dura-ace 9 speed ones. Couldn't even stop with them. Garbage...

put the Travel Agent on there, no problems, felt like normal brakes, stopped fine, extra mud clearance all that stuff...

but, i still prefer the XT cantis i've got on there now...
 
1 - 20 of 30 Posts
Top