dksix

I'm looking at some vintage rigid MTB frames to build up a bike to replace the bike I use to ride the local "rails to trails" bike trails and mixed surface riding. The bike I'm replacing has a worn out low end suspension fork that I can't find a replacement for but all of the rest of the bike works as new.I want to keep costs down by reusing some of my current bike's parts, which is 26" wheels & tires, 8 x 3 Shimano drive with integrated shifter/brake levers and V brakes. I think they are mini V brakes but I'm not sure.

Are the brake posts from vintage frames & forks that were meant for center pulls or cantilever brakes compatible with modern (by comparison) V brakes? I understand the lever pulls would be different, I'm just asking if the posts are compatible is diameter, length and placement for all of the post mount type brakes.

mrv 

https://photos.app.goo.gl/FuQGyEHUbooR1uhW2

- linear pull brakes on an old MTB.
- I just switched to Jones-bars with flat bar levers. I think maybe the mini V-brakes might limit fenders or tire size.
The image linked are Origin8 linear pull brakes. They work just fine considering how cheap they were.
- I'm thinking I'll eventually way-upgrade to Paul mini-motos. Maybe.

Ghrumpy

Post size and spacing for traditional cantilevers will work with linear-pull cantilevers too.

Mountain bikes didn't use centerpull brakes, exactly, but what are called U-brakes. Similar design to centerpulls, but different post spacing and size. They're usually mounted on the rear triangle, below the chainstays. Some, like GT, used them on the seatstays too. Some bikes also had roller-cam style that fit that boss as well, and were used both front and rear, but not many. These bosses are incompatible with traditional or linear-pull cantilevers, since the pivots are above the rim, while cantilevers' pivots are below the rim.

dksix

That's a particularly interesting note about GT's. I was especially hoping to find a suitable GT frameset. I owned a couple of GT's BMX bikes as a kid, thought the way the seat tube went through the top tube looked good and really like the triple triangle frames. I looked back at a couple of listings I've been watching on eBay, one has the rear brakes under the chain stays and I can see what you were saying about the pads being under the pivots but had never paid attention to that before.

Needing a frame in the 21"-23" really limits the number of candidates and that's even more reduced with wanting to spend less than $150. I found a Fuji Thrill that I like but still waiting for the seller to get me the dimensions of the seat tube. I have learned to make sure a frame I'm buying uses a commonly available seat post. There was steel Raleigh M60 that I wanted but I couldn't determine if it was originally a rigid fork bike or not. Then there was a Raleigh Technium Skylite but I was a little put off by the bonded aluminum tubes into steel lugs.

dksix

I like the bike, any information on the particulars or more pictures?

ryansu 

I moved the V brakes and shifter/brake lever combo from a late 90s Motiv (Costco) mtb to a mid 80s Schwinn Mesa Runner and it worked fine[IMG]New brakes by Ryan Surface, on Flickr[/IMG]

Kontact

Most any bike with actual cantis can be upgraded to V-brakes. Just keep in mind that V-brake levers pull a different amount of cable, but there are adapters.


U-brakes and roller cams are not cantis.

Reynolds 

+1 to above, I never had any problems replacing cantilevers with Vs - but you must replace levers too.

mrv 

howdy! sorry for the delay in responding. my photos are on my employer provided smart phone, so i dump them via wifi to a google folder (i'm sure I'm doing something to get me fired for that, but so far so good!)

The bike is a circa 1990 Specialized RockHopper. It is the Taiwan TIG-welded 4130 steel bike, below the Taiwan lugged StumpJumer back in the day.

anyway! i've got the recent photos dumped HERE: https://goo.gl/photos/dWY7zbBkWffWgky26

the images are not really in order (or maybe by the time you click through, they will be! hard to say)

Basically the progression of the bike is something like:
- free bike with flat bars, crazy long low quill stem, canti-brakes, maybe 7 speed trigger shifting (immediately installed a riser stem)
- changed to drop bars (Randonneur) w/ 8 spd bar ends; TEKTRO aero levers for linear pull; ORIGIN8 linear pull brakes (v-brakes)
- (just) changed to Jones SG2.5 bars; Paul Lover Levers & thumbie mounts for the 8-spd shifters; quill stem adapter & new stem
(and somewhere in all there I got a lightly used Brooks, zero offset seatpost, Cliff Hanger wheelset; couple of crank replacements; new bottom bracket)
~ anyway, the headset, bottle cages, frame & fork are still original....

hope all that helps.
Cheers!
mark

dksix

The bars was what peaked my curiosity, obviously that bike is meant some long hours of mixed surface riding. Now that I have looked at more pictures of the bike I'm curious as to how tall you are. As I'm sitting up a bike for path and mixed surface riding I wondering that advantages you find with that style of bar vs flat or drop bars.

dksix

The intent is to use all of the parts from my current bike to a vintage MTB, so all of those components are 100% compatible. I do understand that the different types of brake could have different cable pull requirements. It's always good to get a consensus of positive accounts though.

mrv 

Yes - this is my touring bike & go ride all day to get lunch/coffee & such.
I'm about 6ft even, with my seat to pedal distance right around 96cm (i think.... i don't know where my fit-kit paper work is). I typically ride a 58~60cm road style frame.
This RockHopper is about 53cm for the seat tube, but the TOPTUBE is almost 60cm. (This was a typical '80s~'90s design, really long top tube.)

For a comfortable, upright kind of bike, that's really long. If you check out the geometry on new bike-packing type bikes, they are a bit shorter, I think.

So the drop bars just kicks things out further, even with that ghastly riser stem I was using. So to reach the brake levers, I was stretching. It wasn't too bad, I did a couple of 5 day tours with the drop bar set up.

I started reading about the Jones bars (BikeSnob NYC actually... AND BikePacking.com: List of Comfort MTB Handlebars - Bikepacking.com << CHECK THAT OUT! )

You could say I was "Jonesing" to get more up, further back.
The Jones bars allowed me to do that - push the seat back a bit, get more up right, offers some 'aero' positions on the loop part.

The biggest benefit of the Jones bars are: 1. you can get your hands behind the headtube, for more uprightness; 2. if you get the 2.5SG version, you don't need to use such a ghastly riser stem as I was using.

I've been riding them about 2 weeks or so. I totally dig them. I got the 710mm wide bars. Probably I'll cut them down to the 680 or whatever the shorter width is if I ever re-wrap the bars. 710mm barely gets out my back door.

Hope that helps. I keep wanting to get rid of my RockHopper, but once I look at new bikes, I'm basically buying a new wheel size ~ maybe disk brakes, which I don't really love that much anyway. It turns out that I have what I want ~ just replacement components as necessary!

dksix

Thanks for all the info, the bars are definitely something I'm going to look into but as for the subject of this thread I ended up going a different direction. I came across a deal on an almost complete new hybrid that I speculate was damaged in shipping. It had never been assembled, still had the zip ties holding stuff in place and some of the bubble wrap around the frame tubes but was missing wheels and fork. So for now my old Fuji will remain intact, just not used and maybe sometime I'll run across a fork for it.

I've never tried it or seen any information on people doing it but maybe I'll look into the possibility of swapping the long steerer from the Fuji's fork into another fork. I have all of the parts ordered to complete the hybrid, which was just suitable tires & tubes, a fork and caliper adapters/spacers to allow me to use the 203 mm and 180 mm rotors that were on the 29'er wheelset I have that will be used on the hybrid. Oh yeah, and a 9 speed cassette.

fietsbob

Just if a light thinwall frame/fork tube , the compressing forces splay the posts out in reaction to the force applied.

adding a booster arch cures that..

arex

If the bike is too old, you might run into some weird fit issues, especially on the front fork. It's as if there wasn't a standard placement for the canti posts at first...the manufacturers may or may not have positioned the posts based on the brakes used. I've run into this issue on an '84 Univega touring bike, trying seven different brake sets until I found a set that was usable (mini-V's).