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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

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Old 10-24-13, 01:38 PM   #1
nightfly
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Converting 26inch mtn bike to 700c fixed. Doable? Stupid?

Had an idea to put some 700c wheels on an old 26inch mtn bike (1991 Rockhopper comp). I've already made it a single speed with a simple conversion kit.

I guess the two issues are brake mounts (would only need front) and how it would ride. That is would the geometry be much different. Brakes are currently canti's which I'm sure wouldn't hit at the right spot but maybe there are some hacks for this.

Could replace the fork if needed. Currently it's a 1" threaded I think.

Worthwhile or stupid?
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Old 10-24-13, 01:52 PM   #2
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Pursuit style mountain bike with 700c rear wheel.
l.o.l.

What are you trying to accomplish by doing this? If can be done but the results likely won't be satisfactory. 26x2.0 tires come out to about the same diameter as 700x18. I would rather just keep the bike as is and get some nice 26" tires.

Last edited by hairnet; 10-24-13 at 02:05 PM.
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Old 10-24-13, 02:02 PM   #3
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Doable and stupid I assume your dropouts are horizontal, if not probably best to write this off already. So now if you have horizontal dropouts, is the fork crown and brake bridge drilled out? If so, odds are you can get caliper brakes on there that will be about right for gripping a 700c rim, a couple things to point out, the geometry will not be right, your BB will be way the hell in the hair, stand over will go way up as well, and expect oddities in the steering. If you're curious how I know all this, the answers simple I converted a 26" mtb into a 700c road bike.. it was fun for a while but it's not the greatest thing.. especially since you can buy a hybrid that does what you're doing already and is designed for it, hell maybe that's the answer get a cheap hybrid and a fixed rear wheel for it?


Edit: I didn't even touch tire/wheel clearance.. but if it does not fit the rear, then you must quit. Like you already said, the fork is swappable.. but is it worth the cost and effort?
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Old 10-24-13, 02:18 PM   #4
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It's actually even stupider, it's got vertical dropouts. Already made it a single speed with a magic gear ratio that isn't so match once the chain stretches. Thought maybe I'd spring for a new rear wheel with an Eno eccentric hub if it seemed like it might work. Did I mention the bike is orange? I really like orange. Was trying to make a pseudo Brooklyn Machine Works Ganagsta Track circa 2008 out of it.
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Old 10-24-13, 03:31 PM   #5
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Sounds pretty damn stupid. I say go for it.
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Old 10-24-13, 03:53 PM   #6
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It is doable-but
Here I hope-is a trek 750 (700c hybrid) frame with a 26" Trek rigid fork on the front
with a 700c 40 mm michelin transworld tire both ends.
The tire has about 5mm of clearance above- and plenty of lateral clearance on this typical 26 mtb fork
It will accept a typical caliper brake-there is a mounting hole drilled already-not sure why?
Now not sure all 26" forks will accept a big 700c like that-

Oh-it is a bad idea from any practical point of view.
So why did I stick a 26" fork on a 700c?? No 700c fork-but I did have 2 26" forks-and caliper brakes
I don't think I will leave it like this-I ended up with this not bad frame "by accident" looking for something else-couldn't find it-stupidly MADE AN OFFER- $50+$30 shipping-seemed ok for DB CROMO frame $80-
But the frame I actually wanted-looked for for 3 years-15" Jamis dragon Reynolds-IMMEDIATELY appeared after I bought the Trek 750 frame I really didn't want-too big for me anyway!! No dents-but paint so so- in any case-I screwed up-and put the folks on looking for a way to cheaply turn it into a bike i could sell.

Yeah-don't do it.Pointless expensive waste of time-unless you just like to tinker-in which case- HAVE AT IT!!
Luck
Charlie
PS crummy pictures-in my "junk" room
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Old 10-24-13, 04:00 PM   #7
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It will accept a typical caliper brake-there is a mounting hole drilled already-not sure why?
That 'mounting hole' is pretty standard on all rigid MTB forks of that age, it's not for caliper brakes, but for the cantilever brake guide / fork crown located reflector mounting point
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Old 10-24-13, 04:30 PM   #8
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jimc101
Thanks.
It is conveniently located for caliper brakes.
Here is the same BIG 700c tire on a different but same type- 26" MTB fork of that vintage.
There is adequate clearance-barely-but that is a BIG 700c TIRE

frankly I was surprised the big 700cc tire would fit under that fork??
Not sure I kinda doubt that that is the rule-guessing most rigid forks would NOT accept that big tire wheel
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Old 10-25-13, 06:34 PM   #9
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You could just get some 26" road tires.

That would get rid of the biggest MTB problems.
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Old 10-25-13, 06:37 PM   #10
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phoebeisis......have you not flopped your garage back on it's feet since the last hurricane blew it over??


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Old 10-26-13, 08:19 PM   #11
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You could just get some 26" road tires.

That would get rid of the biggest MTB problems.
+1. I kept my MTB 26" when I converted it to FG, and have put several thousand happy miles on it since.
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Old 10-26-13, 08:54 PM   #12
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I love my 700c on 26" mtb setup, haven't done one fixed, though. lotsa pedal clearance even with 172.5. Long reach RX100 calipers from 1999 reach the rims and clear 38mm cx knobbies with my 395 axle-to-crown rigid fork.



Here she is the other day with cheep road fork and 23mm tires.

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Old 10-28-13, 10:57 AM   #13
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LesterofPuppets that looks really nice ^^

Any issues with this? Looks like you just threw on some rims and brakes and went for it.

Currently mine is a single speed with 26" Ritchey Moby Bites 2.1s. Could probably drop down to some narrower tires.

Any suggestions?

Although that bike above makes just want to throw the wheelset from current fixed gear on see what happens.

Robs
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Old 10-28-13, 11:18 AM   #14
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Just due eet
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Old 11-26-13, 05:45 PM   #15
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i'm doing this on an old autobike (LOL)

here's the original bike's setup:
http://www.bikepedia.com/quickbike/B...c#.UpUyfcQ_vTp


... i'm using it to tow my daughter on her bike using a trail gator. i have 700x28's mounted with plenty of room...can run up to 35 but that's probably overkill if i'm only towing her and her bike. it's a single 44T chainwheel (coast mechanism in the bottom bracket)... and i'm using a 32 spoked wheel out back, with a 7 speed cassette and the shimano sti flat bar/mountain levers (for sidepulls or cantis). for brakes i'll be using single pivot side pulls. can't seem to find the mavic canti adapter plate anywhere. oh, the cassette consists of: 12-14-16-18-21-24-28...looks like a "B" series.

wish me luck...LOL
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Old 11-26-13, 06:08 PM   #16
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doable and stupid both yes. why not just put wide bars on it and ride it in the mud?
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Old 11-26-13, 06:20 PM   #17
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I say do it. With a disk brake.
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Old 11-26-13, 06:55 PM   #18
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doable and stupid both yes. why not just put wide bars on it and ride it in the mud?
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I say do it. With a disk brake.
Were those directed to me, original poster or both of us?

If me, i'm using street tires to tow my daughter and her 20" wheeled bike. And I can run side pulls w/ the existing holes, or cantis if i find Mavic's canti mount...I do believe Xtra cycle sells adapters to run 700c wheels in a 26" wheel frame. but i'm not spending $70 just on two adapters.........
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Old 11-26-13, 09:00 PM   #19
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Asinine! Go for it--and be sure to post tons of pics!!!!
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Old 12-02-13, 09:53 AM   #20
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That Mavic adapter really limits tire size. 28s are as big as you're likely to be able to fit.
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Old 12-02-13, 07:22 PM   #21
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had issues w/ the drivetrain. had too much resistance when trying to pedal with the three (out of 7 speeds) smallest cogs. plus i'm selling my fuji folder and found some mixte bikes for sale.......easier to mount when towing my daughter.....then when she gets past the stage of towing i can use it for touring or heavy shopping duties....
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