Korina

Is it possible? I have a 1995 Trek 730 that I'd like to convert, but I'm not sure it's possible. I gather the canti posts are the issue. Are there long reach canti brakes, or maybe V brakes long enough? TIA for any suggestions.

ironwood

Probably not because the canti posts are at the same height as the rim. On a steel bike it is possible to have a framebuilder move the posts down the fork and seat stay, but is it worth it?

There have been brakes that mounted on posts and pushed directly in to the rim. Bicycle Quarterly had a diagram of one, but the idea never caught on.

brooklyn_bike

they sell cantilever brake post offset post adapters. i've never used them and not positive they'll get you enough drop to do a conversion. let us know if you try them and how they work out:

Alloy Brake Post Extender Bike Bicycle V-Brake Refit Converter
https://www.ebay.com/itm/17444690414...RoCgncQAvD_BwE

The Golden Boy 

You captured my first 2 thoughts.

The big problem is where the canti posts are- they'll be right around rim level- if you move the posts, you're spending money and really messing with the frame- if it doesn't work out, you're out both the money that you did the work with AND you're out the frame. OR, you could mount side pull/centerpull brakes on the brake bridge/fork crown and leave the canti posts unused. (IMO- that looks awful)

My next thought was- just use wider, more supple tires. Without looking at it, but having a general idea of the bike- my guess is you could probably fit 40s in there- if not larger.

My next thought after that is to get sport touring frame and go from there with the wheels and proper length brakes- if you REALLY want 650Bs on an older bike.

RiddleOfSteel

I won't repeat anything the others have said, but looking at images of '95 Trek 730s, those things have loads of clearance for big tires (like 42mm easily) with fenders. So my first question is, why? Usually, 650B is done to be able to keep the frame (that one likes) but get much larger tires on, with fenders, all for a more comfortable ride than before coupled with all weather capability. If you can "have it all" with a 730, and it looks like you can, 650B on this is--for functional reasons, as far as we can tell (since you are simply asking, but not providing any reason for the desire/thought)--pointless. If you have aesthetic or stand-over issues that having large tires + fenders would create, I/we can understand that.

gugie 

Normally I'm the guy that tries to talk people into 650b conversions, but unless you are willing to pay to move the cantilever posts ($) then powder coat ($$) or wet paint ($$$), I'd say pass.

Korina

Thanks guys. I was just trying to reduce standover a bit; sounds like I'll just enjoy what I have.
@brooklyn_bike, those brake extenders look interesting, thanks.

RiddleOfSteel

The standover issue when bumping up tire size considerably is real, and even going to 700x42 from 700x33/30 on larger frames for me definitely is felt. If your 730 was caliper brake instead of canti, then that would be a lot easier and cheaper, and perhaps wouldn't necessitate frame modifications. I had been looking into 650B recently pretty heavily. For those of us that run rim brakes (which is pretty much all of C&V in some way), 650B rim brake wheels are rare and custom building, even if done by one's self, is not a low-cost proposition (or perhaps as low as we would like), no matter how many times I spin the math in my head. Does your size of frame go any smaller (like if you got another one) so as to aid the standover issue if you went with larger tires on that, or does that present other problems (on top of having to look for another frame)?

bark_eater 

If you Google around a bit, there are a couple folks that have done this conversion successfully, and I recall one person was very enthusiastic about it. I think they swapped in a 650 b fork and just moved the rear canti posts. That discussion might have been on the Paceline forum.

gugie 

At that point you've got more $$ in the mods than the OP's bike is worth. Better off finding a different bike.

Korina

I bought the bike for entirely too much money, and it was in worse shape than the photos showed; rivers of rust flowed from inside the frame, one of the spiffy bronze anodized rims is cracked, and the beautiful paint was toast. I took it to the one and only powdercoater in 250 miles, which means they charged whatever they wanted ($180, IIRC). I can't afford to put much more money into it, and I have no hope of getting back anywhere near what I've invested by selling it. I thought I'd ask the experienced folks here about the conversion; since it's not something that can be easily done, I'll just ride and enjoy it as it is.

It's a beautiful emerald green, btw. I was thinking of a green/gold/brown theme, but maybe green/turquoise/brown. One of these days; I picked it up from the powdercoater in April 2020.

Korina

Or even two!

mrv 

$180 is not horrible for power coat. Depending what you get here in the Detroit area, it'll be $100 to $250. I saw a really pretty powder coat at Bikes & Coffee and the bike shop owner said it was about $250. It was a metal flake speckle thing. Guess that drove some cost. Maybe he was including the clean up cost after (chasing threads and installing bearings, etc....)
That's a bummer to pay too much and end up with too little. (....story of my life....)

As far as moving canti-posts, I'm waiting for warmer weather to start rattle canning a project started last fall: https://www.bikeforums.net/classic-v...e-project.html
It's a long term "for fun" project. The wheels will cause a serious cash outlay**, which I'm not in the mood for. But if I get it painted and start hanging parts on it, I'll get motivated to get rid of something else and get this done.

** that is, for new wheels. There are old '80s 650b wheelset that can be had for $75 ~ $100 plus shipping. My past experience with riding old wheels has been negative. So I'll just put my money into new rims & spokes and nice hubs.

fun stuff.

Korina

Nice build @mrv, particularly the thread title; I'm a sucker for word play. I look forward to an update.

I forgot to mention the $80 to have the bike shop chase all the threads; I'd naively assumed the powdercoater would mask everything, since they do lots of bikes. My only real regret is the cracked rim; the bronze anodizing would look amazing with the green. I'll just put it back together and ride it #partypace.

The Golden Boy 

I guess if you're trying to reduce standover, the bike doesn't fit- why not find another bike that fits instead of throwing more time, energy and possibly money at a bike that doesn't fit?

I've always felt it's the worst when it's *almost* there. Like you can totally have an idea of how awesome it'll be, but it just won't let you be comfortable on it.

lonesomesteve

I have to agree. Always best to start with a frame that actually fits rather than play games to make a wrong sized frame work.

Korina

Actually, it does fit fairly well; I wouldn't have sunk so much cash into it if it didn't. I just wanted a little extra standover and a touch less toeverlap. That's not practical, so it'll be fine as is.

mrv 

....hmmmm..... sounds like you need a fully rigid 1990 Bianchi IMPACT MTB (about 21in CtC seat tube) that's been rattle canned Pontiac Blue with some yellow and red fades going on. Yellow cable housing and yellow bottle cages!
Turns out I've got exactly one of those that might be up for sale soon!! Double butted lugged steel! Rides like a..... fully rigid MTB from 1990!

RiddleOfSteel

The green/gold/brown combo reminds me of the 1984 Fuji del Rey with their beautiful green paint, gold/bronze anodized rims, and tan wall tires. Can't find a good in-real-life photo (that isn't FB, which I am not on), so the next best is a catalog photo:



I was also reminded of this 48cm '08 Nashbar Touring frameset that I bought and built up. This is it with monster 700x48c tires. Color-wise, it was beautiful, with those perfect dark anodized rims allowing the tan walls to really contrast.

Korina

Nice try; have you seen my bike list?

oneclick 

Cut the cantilever bosses off and use hub brakes.

wrk101

With super short legs and a very long torso, I have learned to ignore standover. Heck, I had a dual sport motorcycle with a 36 inch seat height once (bicycle inseam is 30 inches). Even on my road motorcycles, I had to be careful which foot I put down as I could not reach with both feet. If the road was slanted away and I chose that side to place my foot, the bike was going to fall over.

Several of my bicycles have zero to negative standover. I focus on TT length instead to accommodate my long torso. None of my bicycle negative standover is close to what I have with motorcycles.

Since you say you are comfortable riding the bike, to me, thats a sign.


YMMV.

bark_eater 

Since this particular bike has already been to the powder coater, I assume the ship has sailed as far as frame modifications. But if were going to continue to speculate, why stop at 650B? Might as well go to 26" RTP wheels. These frames are commonly compared to Trek 520 touring frames but with a jacked up bottom bracket height. If you going to go for it, go big...

scarlson 

Meant to post this earlier, but only managed to get a photo just now.

I just trial-fit 650b wheels on my Colin Laing tandem, which has cantilever brakes and (I think) was designed for 700c wheels. It can work! These are Dia Compe shorty cantilevers, and the adjustment is a little bit extreme, with very long pad posts, as you can see. I may have to file the pads to make them work, but it'll be fine. Naysayers be damned. The BBs are too high on this tandem anyway.



But who knows if it actually was designed for 700c. The brake posts always seemed a little bit low.

Korina

@scarlson, nice! How well do the brakes work?