I recently bought a pair of 700D rims that were setup on early nineties GT Tachyon or Continuum with the intent of using them on one of my 26" vintage MTBs.

Assuming the frame has the clearance to take these rims, the remaining headache is finding brakes (preferably cantilever setup) that will fit on these rims.

Can anyone shed some light on possible options of adapters or specific cantilever designs that have enough adjustment to fit on these 700 D rims.

BTW for those not familiar with this size, 700D is essentially a 650B wheel that is about 3mm wider in diameter than a 650B.

Many thanks
C

I've successfully set up 650b on a vintage mtb using tektro oryx cantilever brakes. I was at the very top of the adjustment though. Tektro's seem to have the most adjustment for the price.
Paul cantis should have suitable adjustment as well. The moto lite V brakes certainly will.
There's a few threads touching on the subject recently.

I'll ask the question, "why?"

Not because I have intent to criticize or discourage. I am just curious as to your vision here.

That is a good question, curiosity of handling and speed while maintaining the element of vintage nostalgia is my idea.

Most of my active mountain bikes have slick tires (1.1 to 1.6) as I ride them on asphalt for lack of better natural environment where I am.

Coming across a pair of Araya RM20s in size 700D and having a fascination with the GT Tachyon and Continuum kind of triggered this idea.

These rims carry the original tires in 700D x 1.4 which I intend to eventually replace with some city slick 650b tires.

This bike is a 52cm Miyata Ridge Runner TACO made and sold in the Japanese market, it is similar in Geometry to Miyata's 1993 elevations.
I am debating whether to go for the Cantilever setup or simply buy the Paul's V brakes as I have both levers available. Paul 's V brakes are better and way more expensive.
Planning to replace the original suntour 36h hubs with XTR M900 ones.

C

Thank you for the input, since the 700D is about 3 mm wider than the 650b, am concerned about the Oryx Cantilever compatibility since you mentioned they were at the very top of their adjustment range.

do you think that will still work ?

i would love to keep it as a canti brake setup to retain the XTR M900 setup I got planned for this project.

Sounds like a fun project. I'm in the midst of a project to convert a steel MTB to a more versatile drop bar setup. I had toyed with the idea of 650B, but when I saw Compass will be soon releasing 559's with the desired ride quality in 54mms, I decided to go with new 26" wheels and the tires, rather than 650B. Still about a month off from getting it on the road. The old Shimano Alivio cantilevers stop as well as anything I've ever had, so that helped with the decision.

Eager to see your end results when you get there.

[MENTION=306540]concordino[/MENTION]

You may be in luck.. Since I happen to have a Tachyon kicking around (doesn't everyone?)...



700d wheel in a 26" fork with tektro oryx at highest adjustment. Pad almost hits the tire. I'd say you are in luck. (FWIW brake post center to axle center is 253mm +/-1mm)

[MENTION=205507]4funbikes[/MENTION],

thank you for sharing the info and clearing any doubts I've had. I was leaning more towards an deore XT M 737/739 and Paul's components Moto Lite Linear V brakes.

With your confirmation the XTR M900 is back on the table given I am rebuilding the wheels with M900 hubs.

much appreciated and please share some pictures of your Tachyon.

C

[MENTION=19743]USAZorro[/MENTION],

You got me curious as to this Compass bikes new offering and tried to access their website just to get an idea but it was under maintenance. Have you any pictures to share of this upcoming bike ?

thanks

It isn't a Compass bike. It is a new tire that they will begin selling shortly. The bicycle I am adapting is a 1990's Giant Iguana frame and fork. It will be my interpretation of a "go almost anywhere" bicycle that will hopefully be a joy to ride on the road as well as the trail.

Today, I managed to complete this project and test ride it. Overall i am pleased with the results. It rides fast and pretty rigid, although the next upgrade will have to be the tires.

I elected to keep the original ones, so as to have a feel for what the original GT bikes were. The next order will have to be fatter slicks.

The forks and stays have enough clearance to take a slick in double the size. Advice on tires and sizing are welcome.

Just to clarify, 700D rims are 3mm bigger than 650B in diameter, not width. Have you tried to put a 650B tire on those rims yet? I expect they will be very tight, if they can be installed at all. THe difference between 700C and 27" is 8mm and it is not possible to put 700C tires on 27" rims ime.

+1, 700D and 650B have different Bead Seat Diameters (BSD). You may have a hard time stretching the tire bead on to the rim.


If I were you, I'd try the Pacenti/Panaracer Pari-Moto tires. $32 each, available in 38 and 42 mm widths.
+) they roll super fast
+) they're cheap
+) their beads were a little floppy and not very tough to mount on the rim, so you may have a chance of stretching them over your larger rims
-) they're super lightweight and not very thorn proof. I've had great luck on city streets with occasional glass (no flats in >1000 miles), but we don't have nasty goathead thorns in the midwest.

Switching to a larger-diameter rim, you could get the lost braking leverage back by using a V-type brake with your M900 or other canti-type shifters/levers.
The wider rim will itself further reduce leverage due to the change in pad-dive angle, so strong, low-effort braking can still be part of your conversion if you use a v-brake.

If the canti's are more affordable/convenient to use, a ratio-altering pulley adaptor (such as from Problem Solvers) might restore lost leverage, but are typically oriented in a 90-degree routing to replace the "noodle" on a v-brake. Such an angle just might be accommodated above the front and rear cable housing stops and still give a tidy routing to the lever.

The cable travel multipliers can be used but you have to install them backwards to increase leverage instead of increase cable travel. I accomplished this by installing them against the barrel adjuster of the lever so the cables run straight down as they begin their journey to the brakes.

edit: here is what I mean: