Convert from disc brakes to v brakes
 

Hi community,

I have a 2013 Marin Muirwoods 29er. I am thinking of converting my bike to an e-bike using a Copenhagen Wheel.

To install the wheel, the bike needs to have rim brakes. My bike has disc brakes. Would it be possible to install rim brakes and what would that entail? Here's a link website with specs.

You can probably tell I know next to nothing, but I can get help from a friend who is a bike mechanic.

Thank you,
Bryce

No, as the bike lacks the mounts on the seat stays.

You could have them retro fitted, but the cost of this (brazing the mounts and having the frame re-painted, which it would need after the brazing) would probably exceed the cost of just getting a frame with rim brake mounts on in the first place.

An (unpopular) option would be to forego the rear brake altogether. A single front disc brake will stop your bike almost as quickly as a mated pair.

Joe

wear a full face helmet then. un safe should be more un popular than it is.. :rolleyes:

Hi,

I took the bike to a mechanic today and they said they could install rim brakes. Maybe I got the year wrong on my bike? I am not sure, but please tell me if you think this opinion sound suspicious.

Thank you,
Bryce

To install v-brakes or cantilever brakes, you need bosses (posts) brazed to the frame and/or fork. No bosses, no v-brakes. Those aren't the only types of rim brake, though. If your frame has a brake bridge, a caliper brake can be fitted. You'll need brake levers with the correct pull ratio, though. Caliper and cantilevers use one pull ratio. V-brakes and discs use another. If you use a lever with the wrong pull ratio, braking will be less than ideal.

The replies above aren't wrong, though, as your original post's title specifically mentions v-brakes, not rim brakes of any type.

If your bike is this Marin Bikes | 2013 Muirwoods 29er | Mountain Bikes, Road Bikes, and City/Commuter Bicycles | us there is no where/way to fit rim brakes, have a look a this thread from an owner, lots of pics, again, no where to put rim brakes http://www.bikeforums.net/commuting/...many-pics.html

If you had a 26" model, then it comes with rim brakes, but this was only produced till 2012 2012 Marin Muirwoods - BikePedia

Not seeing anything in those pics that definitively rules out there being a brake bridge on that bike and it appears the rear fender may be attached that way. Agree he cant do V brakes but, if there is a bridge, a caliper should be doable.

The bike shop is probably right, you should be able to install a (long reach) caliper brake on there. Braking will not be great but it's the rear brake so it really doesn't matter that much.

Hi,

Thank you. Yes, that is my bike, I think. Mine could be 2012.

On my bike there is a single hole where it appears some sort of braking system could be mounted above the rear wheel - at least that is what the mechanic said when he said brakes could be installed. Not sure if that's right, though, and am now thinking I should get a second opinion.

Thank you again for your help.

Bryce

Depending on the tire size and clearance, there are a lot of callipers that would work.

I had to drill out the brake bridge on my Litespeed before going from V-Brakes to callipers. But it generally isn't insurmountable. There may be some ways to adjust the mount downward a bit if necessary.

The Canti bosses are very cheap, so you could braze them on if that is a possibility. The may well be better than trying to kludge some long reach callipers onto the bike. However, as others have mentioned, you will need to braze them on, then paint the affected area.

CANTI AND "U" BRAKE BOSSES :: STEEL SMALL PARTS :: BRAZON/SMALL PARTS :: Nova Cycles Supply Inc.

You may find it better to just buy the frame with the desired mounts and build up from scratch. Do you need to do any welding for your electric conversion?

Thank you for your reply. I am now fairly confident I can modify my bike to fit rim brakes.

There is a small hole on the seat stay that a mechanic says appears to be intended for a rack or fenders. This mechanic said the hole was too small for the bolts on modern brakes. It is also farther from the tire than typical mounts.

I took the bike to a hardware store this morning. The technician said that he could bore out the hole to fit a modern brake bolt. He also said that he could make a drop bolt, so that the brakes could be installed closer to the tire. Essentially, in two pieces of metal of the same size, he would bore a pair of holes, one the size of the hole on the seat stay and one the size of the bolt on modern rim brakes. He would attach the pieces of metal to the hole on my seat stay, then attach the brakes to the piece of metal. This would get the brakes closer to the tire.

I am now going to get another opinion from a mechanic at a shop with a very good local reputation - the mechanic is friends with the technician. I am going to see what he thinks of the two options I mentioned above. I will update when I find out what he says. I also intend to upload pictures to show everyone the procedure, in case anyone is interested in pursuing similar modifications to their bicycles.

Thank you all for your help. Also, I do not have to do any welding to install the Copenhagen Wheel. Thank you.

Bryce

I'm not a big fan of drop bolts, mostly because they look so kludgy. But I will probably give them a try someday. You're making this into an e-bike anyway so who cares what the brake looks like.

More info on drop bolts: Home Made Drop Bolts