Bicycle Mechanics - Replace center pull with V brakes

I have an older rigid frame mountain bike that I am updating. It has weak center pull brakes that I would like to replace with a set of Avid single digit five V brakes. The bike has 8mm diameter pillars for the brake pivots. Is this a standard pillar diameter that will accomodate the V brakes, or do I need to get innovative to mount the Avid's?

The brake mounting studs will be fine. The issue that you need to check on is if and where your bike has a rear cable housing stop. You are going to need one for linear pull brakes. You'll also have to replace your brake levers with ones that have more cable pull.

The brake mounting studs will be fine. The issue that you need to check on is if and where your bike has a rear cable housing stop. You are going to need one for linear pull brakes. You'll also have to replace your brake levers with ones that have more cable pull.

V-brakes don't require a cable stop. The cable housing goes right into the noodle on the brake. Everything else is correct, however.

I believe the confusion is from the OP use of the term "center pull" I think he has cantis and is moving to v-brakes.

Also, are you upgrading your brake levers? There is a difference in the amount of pull between cantis and v-brakes. They are not compatible.

V-brakes don't require a cable stop. The cable housing goes right into the noodle on the brake. Everything else is correct, however.

And where does the other end of the cable housing go? Lots of canty equipped bikes have a cable housing stop at the front of the top tube and just some kind of noodle to guide the cable around the seat post to the straddle hanger.

You can increase the power of cantilevers by installing a yoke on the centre cable, and running a low straddle cable across it. Easier brake pad set-up can be achieved by buying modern cantilevers, which use the same type of pads as the V brakes. No change of brake levers or cable run needed.

And where does the other end of the cable housing go? Lots of canty equipped bikes have a cable housing stop at the front of the top tube and just some kind of noodle to guide the cable around the seat post to the straddle hanger.

the other end of the cable housing goes into the brake lever, silly. There's no rule that you have to interrupt the brake cable outer. In fact SOME crazy people like me invent quite the opposite rule for their off-road bikes!

- Joel

Thanks for the responses.

I pretty much tried everything with stradle cable adjustment trying to get better leverage, but the center pulls on this bike require a very heavy lever pull for anything like agressive brakeing. This bike will use full cable housings from lever to noodle, so no problems there. I am changing levers to longer travel units to match the sensitive pull and the longer cable movment of the v brakes.

Thanks again for confirming the 8mm pivot bore for the V brakes.

Thanks for the responses.

I pretty much tried everything with stradle cable adjustment trying to get better leverage, but the center pulls on this bike require a very heavy lever pull for anything like agressive brakeing. This bike will use full cable housings from lever to noodle, so no problems there. I am changing levers to longer travel units to match the sensitive pull and the longer cable movment of the v brakes.

Thanks again for confirming the 8mm pivot bore for the V brakes.
It *sounds* like the brakes you have are cantilever brakes (different from centerpull road brakes). Cantilever posts are interchangeable with V-brake posts.

However, there is another type of brake called U-brakes. They use posts which are NOT interchangeable with canti/v-brake posts, and is common on older MTBs.

Read this glossary entry on U-brakes: http://www.sheldonbrown.com/gloss_u-v.html#ubrake If what you have are U-brakes, then unfortunately you can't replace them with V-brakes.

I would check out all of the maintenance points before I switched to V-brakes. My old school Deore cantis will lock up the front and send me over the bars. Check the cables and housings. Are the cables rusted? Are the housings kinked, do they have enough lube or are they dry? If they aren't lined then they need to be greased. Are the straddle cables adjusted properly? Are the pads toed in correctly? Are the pads new or old and glazed over. Pads can be sanded to provide like new stopping power.

Most riders who complain about cantis, don't have them adjusted properly. Cantis stop very well when properly adjusted. Good luck

Tim

Most riders who complain about cantis, don't have them adjusted properly. Cantis stop very well when properly adjusted.

On the other hand, decent quality linear pulls are so much easier to adjust.

And where does the other end of the cable housing go? Lots of canty equipped bikes have a cable housing stop at the front of the top tube and just some kind of noodle to guide the cable around the seat post to the straddle hanger.

It sounds like you're describing may daughter's '92 Trek 850. I had some vintage Hershey linear pull brakes that I wanted to put on it so I ran housing from the noodle on the frame to the noodle on the brake. It's not my best work, but she's got great brakes.

Short bridge wires aren't always the best setup for cantis. If you have the old non-low profile type with horizontal arms, long bridge wires work best.

And where does the other end of the cable housing go? Lots of canty equipped bikes have a cable housing stop at the front of the top tube and just some kind of noodle to guide the cable around the seat post to the straddle hanger.

Okay, I see where you are going now. But it still shouldn't be a problem. If the bike has a split cable system (middle section of cable is exposed) there is still going to be somewhere for the cable end on the top tube near the seatpost. Just run a long cable housing from there to the v-brake. If the bike has cable housing all the way from the lever to the brake, you just need a longer cable housing.

I can also see the problem that you are discribing but, honestly, I don't think that's going to be a problem except on a very few exotic bikes. Most of the time that extra noodle to guide the cable to the straddle hanger is going to be a piece of cable housing anyway.

It sounds like you're describing may daughter's '92 Trek 850. I had some vintage Hershey linear pull brakes that I wanted to put on it so I ran housing from the noodle on the frame to the noodle on the brake. It's not my best work, but she's got great brakes.

Short bridge wires aren't always the best setup for cantis. If you have the old non-low profile type with horizontal arms, long bridge wires work best.

Yep, that's what I have - short horizontal arms on the original brakes. This pretty much defeats the leverage gain from a shorter bridge cable by fouling up the vector pull angle on the short horizontal arms. There just does not seem a way to improve the stock setup. I am sure the Avid V brake replacment will turn this around. For 27 dollars for the set shipped on Ebay, how can I go wrong unless they won't fit!!

You will need new brake levers as well. The ones you have now will not have enough cable pull.

I can also see the problem that you are discribing but, honestly, I don't think that's going to be a problem except on a very few exotic bikes. Most of the time that extra noodle to guide the cable to the straddle hanger is going to be a piece of cable housing anyway.

Trust me, I've done a bunch of these conversions and the #1 bug-a-boo is the rear cable stop. It's a common enough problem that Problem Solvers manufacturers $25.00 clamp-on cable stops in four tubeing sizes.

Trust me, I've done a bunch of these conversions and the #1 bug-a-boo is the rear cable stop. It's a common enough problem that Problem Solvers manufacturers $25.00 clamp-on cable stops in four tubeing sizes.
Or, how about this: http://www.nashbar.com/profile.cfm?category=69&subcategory=1015&brand=&sku=11619&storetype=&estoreid=&pagename=Shop%20by%20Subcat:%20Brake%20Accessories

For $1 it makes a cable stop next to your seatpost bolt. Seems like a great idea and a lot cheaper than $25 :) Cable position might not be ideal for v-brakes, but it seems worth a try!

Or, how about this: http://www.nashbar.com/profile.cfm?category=69&subcategory=1015&brand=&sku=11619&storetype=&estoreid=&pagename=Shop%20by%20Subcat:%20Brake%20Accessories

For $1 it makes a cable stop next to your seatpost bolt. Seems like a great idea and a lot cheaper than $25 :) Cable position might not be ideal for v-brakes, but it seems worth a try!

How is a cable hanger for cantilever brakes going to help? Parallel pull brakes don't use a cable hanger. The housing runs all the way to the brake, just like a sidepull road brake.

How is a cable hanger for cantilever brakes going to help? Parallel pull brakes don't use a cable hanger. The housing runs all the way to the brake, just like a sidepull road brake.
Because of the situation that RG and cyccommute are talking about, when converting a bike from cantis to v-brakes, an extra cable stop near the seatpost may be needed (if to do nothing more than to guide the housing).

Because of the situation that RG and cyccommute are talking about, when converting a bike from cantis to v-brakes, an extra cable stop near the seatpost may be needed (if to do nothing more than to guide the housing).

That makes no sense at all. When converting from cantis to parallel pull, you would remove the cable hangers, not add one. I'm speaking from experience.

http://thumb9.webshots.net/t/48/49/0/21/49/315602149Nffapq_th.jpg (http://sports.webshots.com/photo/1315602149068014369Nffapq)

It sounds like you're describing may daughter's '92 Trek 850. I had some vintage Hershey linear pull brakes that I wanted to put on it so I ran housing from the noodle on the frame to the noodle on the brake. It's not my best work, but she's got great brakes.

Short bridge wires aren't always the best setup for cantis. If you have the old non-low profile type with horizontal arms, long bridge wires work best.

Sounds like my hack job on my '95 Stumpjumper: I found some old housing and butted it up against the existing housing to fill the gaps. Now I'm running solid housing lever to brake. Looks like ass, but works just great. That's the downside to having all your old parts in your shop: you never go out to buy anything because you have stuff that pretty much works right there in your house. Frankenbikes abound.

Sounds like my hack job on my '95 Stumpjumper: I found some old housing and butted it up against the existing housing to fill the gaps. Now I'm running solid housing lever to brake. Looks like ass, but works just great. That's the downside to having all your old parts in your shop: you never go out to buy anything because you have stuff that pretty much works right there in your house. Frankenbikes abound.

It's no fun if it's too easy. Anybody can bolt on parts that fit perfectly.

Or, how about this: http://www.nashbar.com/profile.cfm?category=69&subcategory=1015&brand=&sku=11619&storetype=&estoreid=&pagename=Shop%20by%20Subcat:%20Brake%20Accessories

For $1 it makes a cable stop next to your seatpost bolt. Seems like a great idea and a lot cheaper than $25 :) Cable position might not be ideal for v-brakes, but it seems worth a try!

You haven't done this, have you? The cable stop that you're talking about faces the wrong way.

That makes no sense at all. When converting from cantis to parallel pull, you would remove the cable hangers, not add one.
Certainly. But if you re-read Retro Grouch's posts, and look at a few old MTBs, you'll see that many of them have no kind of cable guide whatsoever for the rear brake, except for a very thin tube that snakes around the seatpost and can only hold a bare cable, not a cable with housing.

As pointed out above, if you have a portion of unhoused cable on the top tube, and you're using a V-brake, you need some kind of cable stop on the top tube near the seat post.

I suggested the Nashbar hanger because I thought it might be possible to modify it to satisfy this purpose adequately, and it would be more secure than a zip-tie, and cheaper than the $25 clamp-on guides.


I'm speaking from experience.
Likewise, dude :rolleyes:

Have a look at this photo of my old Trek hybrid (http://myxo.css.msu.edu/danimal/bike/trek_oct2004.jpg), which suffered from the exact problem under discussion: unhoused cable on the top tube, but no housing stop near the seatpost... thus making it hard to install V-brakes.

You haven't done this, have you? The cable stop that you're talking about faces the wrong way.
No, I've not used that particular part. However, from the description, it looks like it would be possible to flip it around so it faces forward from the seatpost, thus allowing it to serve the purpose of a top-tube mounted cable stop with the housing headed towards the rear brake.

As far as I can tell, the part is designed to attach to the seatpost clamp bolt and face backwards, thus providing a front-facing cable stop behind the seat clamp. But I see no reason it couldn't be flipped around to provide a rear-facing cable stop in front of the seat clamp.

For $1, seems like it might be worth a shot.

Actually, "dude", I think it may work. I'll give it a try on my daughter's bike this weekend. It can't look any worse than the way I've got it set up.

Actually, "dude", I think it may work. I'll give it a try on my daughter's bike this weekend. It can't look any worse than the way I've got it set up.
Wait a sec... are you actually saying you think my idea is good? :D

Or did I completely misinterpret your post :)

Wait a sec... are you actually saying you think my idea is good? :D

Or did I completely misinterpret your post :)

It wasn't easy for me. Not so much to admit you're right, but to admit I'm wrong.

It wasn't easy for me. Not so much to admit you're right, but to admit I'm wrong.
Hahaha. Well I appreciate it :)

FWIW, I did the same thing as what you did on your daughter's brake with my hybrid. Didn't work so well on mine, mostly because the "frame noodle" (or whatever it's called) was at a very awkward angle for conncting to a V-brake noodle, and created a surprising amount of cable drag.

Anyway, hope you can improve on it!

That Nashbar hanger is a nice piece for the price, but the hole for the seatpost bolt is roadbike size (8MM). I made a shim with brass tubing to get it to fit the bolt on my Trek 930 mtb.

That Nashbar hanger is a nice piece for the price, but the hole for the seatpost bolt is roadbike size (8MM). I made a shim with brass tubing to get it to fit the bolt on my Trek 930 mtb.
Clever! I'd be interested to see a photo of it set up for V-brakes, if you get a chance.

I will post a picture when I get to that project. I'm preoccupied with another bike problem today.

My Fuji mixte frame arrived today and I've got another brake cable routing problem. I think the bike had one of those upside down girls' bike rear brakes. There's another cable guide a few inches back from the seat tube on the center stay. I want to make Shimano 600 centerpulls work on it. This is the best I've been able to come up with:
http://thumb9.webshots.net/t/28/29/2/75/63/2359275630068014369rKhQgG_th.jpg (http://sports.webshots.com/photo/2359275630068014369rKhQgG)
It will look better with some nicer clamps, but it's still pretty lame. Got any better ideas?

It will look better with some nicer clamps, but it's still pretty lame. Got any better ideas?

I don't have any better ideas off of the top of my head. I checked my QBP book for a brake caliper that looked like you might be able to reverse the cable pull hardware. Other than a Tektro caliper that looks like a Weinmann/DiaCompe clone, I didn't see anything. I also looked for top tube cable clamps, but I couldn't find them anymore either. If it was my bike, I'd probably do the same thing that you did.

I don't really want to change the brake. Those 600's are nice. Loose screws has stainless top tube clamps and I think I have a bag of them somewhere. I guess I'll leave the cable like that and hope those bends don't create too much friction. It's going to have upright bars, so maybe I'll be able to find levers with springs.

I like the rear brake setup on the Raleigh mixte much better, even though I'm not a big fan of centerpulls.
http://thumb9.webshots.net/t/59/659/7/36/88/2217736880068014369VNpklt_th.jpg (http://sports.webshots.com/photo/2217736880068014369VNpklt)

I like the rear brake setup on the Raleigh mixte much better, even though I'm not a big fan of centerpulls.
That does look nice! I dunno why all mixte frames don't put the brake bridge on the mixte stays...

I was talking to my bike shop guru yesterday evening about this very topic for 2 of my bikes (before i logged into this forum). He told me that I should be very careful if I do the conversion. Because of the increased braking pressure exerted by V-brakes the seat stays can twist (or the mounting posts for the brakes) on frames not designed for V-brakes leading to metal fatigue and catastrophic failure (the mounting posts will bend and eventually snap off). If you make this conversion while doing most of your riding in flat areas don't try to ride in a city like San Francisco where you'll be using your brakes constantly. I trust this mechanics advice based on his own experiments (and just plain hardcore riding) that have resulted in numerous trips to the emergency room and multiple shoulder surgeries. It's not just the brakes you're changing, you're changing stress on the frame too.

First, I don't think the Nashbar rear cable hanger will work as a cable stop from the other direction, because it would be under compression toward the seatpost instead of tension from the seatpost, which would cause it to rotate around a lot to find the shortest distance for the cable when the brake lever is pulled. I've used these on multiple old road bike builds with centerpull brakes, and I like them. It could work but it's pretty iffy in my mind.
And especially for the rear brake (where you don't need nearly as much braking power) I'd say just stick with the current cantilever brakes, but soup them up into better working order. Front will benefit more from a stronger brake.

I don't know if anyone has linked Sheldon Brown's article on cantilever adjustment, but here it is (sorry if it's a redundant repost):
http://www.sheldonbrown.com/canti-trad.html

First, I don't think the Nashbar rear cable hanger will work as a cable stop from the other direction, because it would be under compression toward the seatpost instead of tension from the seatpost, which would cause it to rotate around a lot to find the shortest distance for the cable when the brake lever is pulled. I've used these on multiple old road bike builds with centerpull brakes, and I like them. It could work but it's pretty iffy in my mind.
Well... I had thought about this when I proposed that hanger as a solution. I'm not sure how much of a problem it will be in practice though. If it's tightened down enough, the friction of the seatpost bolt should hold it pretty well. The other issue is the stiffness of the hanger... presumably it's not so weak that it will buckle from the compression.

Nah, the hanger itself is plenty stiff. But usually it's just hanging on the seatpost bolt, not clamped between the frame or seat collar unless they come really close together. But the hanger itself is pretty thin and designed to be able to rotate freely on the bolt.

If I were to propose a solution, I would just get a clamp-on cable stop, that clamps onto the tubing. Like what was used on old Schwinns before they started brazing cable stops into the frame. I assume stuff like that is still available.

After looking at Sheldon's website, this (http://sheldonbrown.com/harris/cables.html) is the only thing I can come up with. It's a shifter stop but should work for brake cables. Most mountain bikes with the sort of cable routing in question probably have 28.6mm diameter top tubes.
http://sheldonbrown.com/harris/images/doublestop.jpg

But I'd guess that an LBS will have a clamp-on cable stop, too.

I was talking to my bike shop guru yesterday evening about this very topic for 2 of my bikes (before i logged into this forum). He told me that I should be very careful if I do the conversion. Because of the increased braking pressure exerted by V-brakes the seat stays can twist (or the mounting posts for the brakes) on frames not designed for V-brakes leading to metal fatigue and catastrophic failure (the mounting posts will bend and eventually snap off). If you make this conversion while doing most of your riding in flat areas don't try to ride in a city like San Francisco where you'll be using your brakes constantly. I trust this mechanics advice based on his own experiments (and just plain hardcore riding) that have resulted in numerous trips to the emergency room and multiple shoulder surgeries. It's not just the brakes you're changing, you're changing stress on the frame too.

The solution to excessive flex in the seatstays due to braking is a brake booster, which is an arch that attaches at each brake boss, along with the brakes. It will stiffen everything up and eliminate any "fade" in the brakes due to flexy stays.........Shimano's "servo wave" v-brake levers are notorious for transferring enough force to the brakes to flex the seatstays. These levers come with removable "leverage blocks", and if you remove the blocks, you increase the levers' leverage quite a bit. I noticed excessive flex in the seatstays on an aluminum framed bike after I installed some XT v-brakes and XT servo wave levers (with the leverage blocks removed), installed Salsa brake boosters, and now the brakes are absolutely solid, I really can't imagine stronger rim brakes. And there's no detectible flex in the seatstays now. When Shimano first introduced the high-leverage servo-wave levers, they recommended brake boosters be used with them, I found out later-

Well... I had thought about this when I proposed that hanger as a solution. I'm not sure how much of a problem it will be in practice though. If it's tightened down enough, the friction of the seatpost bolt should hold it pretty well. The other issue is the stiffness of the hanger... presumably it's not so weak that it will buckle from the compression.

I wouldn't bet the rent money on that.

If I were to propose a solution, I would just get a clamp-on cable stop, that clamps onto the tubing. Like what was used on old Schwinns before they started brazing cable stops into the frame. I assume stuff like that is still available.
Yeah, I've seen those too. But the modern ones sold by Harris are so... damn... ugly. And expensive too. I have some old ones that I pulled off my Fuji before converting it to fixed gear that are much prettier.

Yeah, I've seen those too. But the modern ones sold by Harris are so... damn... ugly. And expensive too. I have some old ones that I pulled off my Fuji before converting it to fixed gear that are much prettier.
Yeah, I've got some of the old Shimano cable stops, chromed-steel, from old Schwinns and the Miyata. They can mark up the paint job in a way that the one from Harris won't, but I agree that they look pretty, and should be much cheaper.

Here (http://www.loosescrews.com/index.cgi?d=single&c=Cable/Casing&sc=Clips/Stops/Guides&tc=Cable%20Guides&item_id=SH-6229110.1&id=717221019603)'s the Shimano ones I'm talking about:
http://www.loosescrews.com/Product_Images/SH-6229110.1.jpg (http://www.loosescrews.com/index.cgi?d=single&c=Cable/Casing&sc=Clips/Stops/Guides&tc=Cable%20Guides&item_id=SH-6229110.1&id=717221019603)

But surprisingly, I didn't find anything else on Loose Screws website.

Most riders who complain about cantis, don't have them adjusted properly. Cantis stop very well when properly adjusted. Good luck

There is still a very noticeable difference. I used to be a bike mechanic, and when we first started selling V brakes, the head mechanic was tripping out. When I walked into the shop, he told me to take this new bike for a test ride, then laughed his @$$ off when I almost went over the bars.

If I were to propose a solution, I would just get a clamp-on cable stop, that clamps onto the tubing. Like what was used on old Schwinns before they started brazing cable stops into the frame. I assume stuff like that is still available.

Check post #16. The only real drawbacks are that the regular retail price will be around $25.00 and it's going to be a special order part so you have to plan ahead.

Yeah, I've got some of the old Shimano cable stops, chromed-steel, from old Schwinns and the Miyata. They can mark up the paint job in a way that the one from Harris won't, but I agree that they look pretty, and should be much cheaper.

Here (http://www.loosescrews.com/index.cgi?d=single&c=Cable/Casing&sc=Clips/Stops/Guides&tc=Cable%20Guides&item_id=SH-6229110.1&id=717221019603)'s the Shimano ones I'm talking about:
http://www.loosescrews.com/Product_Images/SH-6229110.1.jpg (http://www.loosescrews.com/index.cgi?d=single&c=Cable/Casing&sc=Clips/Stops/Guides&tc=Cable%20Guides&item_id=SH-6229110.1&id=717221019603)

But surprisingly, I didn't find anything else on Loose Screws website.
Yeah, I got ones like those except without the long tab on the bottom... they're just little sheet-metal bands with two cable stops on them, made by SunTour. Looks like they should cost about $1 :) Too bad they don't make 'em anymore.

Yeah, I got ones like those except without the long tab on the bottom... they're just little sheet-metal bands with two cable stops on them, made by SunTour. Looks like they should cost about $1 :) Too bad they don't make 'em anymore.

You've got to match the tubeing sizes too. The ones in the picture look like they fit a standard diameter steel frame downtube.

You've got to match the tubeing sizes too. The ones in the picture look like they fit a standard diameter steel frame downtube.
Yep, all the old SunTour/Shimano ones are for standard steel downtubes.... don't think they'd fit an aluminum frame.