Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 01-01-11, 01:49 PM   #1
zzzzz
Member
Thread Starter
 
Join Date: Apr 2010
Bikes:
Posts: 41
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
700c conversion to 26 wheels

can i convert a 700c bike to mtb wheels? anything i missed before I get the wheels?

the front n back caliper have been changed to larger
tires would be the smaller type and fits.
what about the back wheel portion?


is the width of the 6 speed equal to 7 or 8?
zzzzz is offline   Reply With Quote
Old 01-01-11, 01:53 PM   #2
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Rock Springs, WY
Bikes: My War
Posts: 26,860
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 302 Post(s)
What frame are you using? Pics?
You're using caliper brakes? What calipers are you using? You'd need a massive drop bolt and some long arm calipers to reach a 26"
Why are you doing this?

Quote:
Originally Posted by zzzzz View Post
is the width of the 6 speed equal to 7 or 8?
Sometimes. Answer my first question about the frame. Make/model/year, and I'll have some more for you here.

Many 6sp MTB wheels are set up for a 130 dropout width, which is pretty common for 8 speed road frames, for instance.

Last edited by LesterOfPuppets; 01-01-11 at 02:01 PM.
LesterOfPuppets is online now   Reply With Quote
Old 01-01-11, 02:00 PM   #3
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 20,390
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 643 Post(s)
650b is closer to 700c 622 - 584/2 = 19mm radius drop. those are popular conversions lately.

put 559, 26" in that calculation and the drop is 31.5mm
fietsbob is offline   Reply With Quote
Old 01-01-11, 02:02 PM   #4
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 29,945
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 359 Post(s)
Since you've measured brake reach and believe that's OK, you've cleared the biggest mechanical hurdle. There are some issues of rear axle width, but you can simply measure yours and read the specs for what you're buying. Worst comes to worst, you can spread the rear triangle of your metal frame to fit the new axle.

The one thing you should keep in mind is that you'll be lowering the bottom bracket and losing some pedal to ground clearance. It's a difference of almost 1" from the rim but will be less than that depending on the comparative width of the tires used.

The only thing I can suggest, is that you ask yourself what you hope to gain by the switch, and decide that it makes sense for your needs before spending dough on a pair of wheels and brakes.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Old 01-01-11, 03:24 PM   #5
M_S
Senior Member
 
Join Date: Dec 2006
Bikes:
Posts: 3,693
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I'll make it simpler: Without disc brakes or welding on cantilever studs in the right place, no you cannot. 650b might work, and would screw up the geometry way less.
M_S is offline   Reply With Quote
Old 01-01-11, 04:01 PM   #6
tcs
Palmer
 
tcs's Avatar
 
Join Date: Mar 2007
Location: Parts unknown
Bikes:
Posts: 4,705
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Quote:
Originally Posted by zzzzz View Post
can i convert a 700c bike to mtb wheels?
The Cannondale Bad Boy models are designed to use either 700C road or 26" mtb size wheels.
tcs is offline   Reply With Quote
Old 01-01-11, 04:28 PM   #7
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 29,945
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 359 Post(s)
Quote:
Originally Posted by tcs View Post
The Cannondale Bad Boy models are designed to use either 700C road or 26" mtb size wheels.
They should have called it the "Hamlet", as is for folks who can't make up their minds.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Old 01-01-11, 04:30 PM   #8
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Rock Springs, WY
Bikes: My War
Posts: 26,860
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 302 Post(s)
You can run 26" on pretty much any disc equipped 29er if you really wanted to.
LesterOfPuppets is online now   Reply With Quote
Old 01-01-11, 04:36 PM   #9
shouldberiding
Senior Member
 
shouldberiding's Avatar
 
Join Date: Aug 2008
Location: Madison, WI
Bikes: '08 Trek 7.3FX
Posts: 811
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by LesterOfPuppets View Post
Why are you doing this?
I'd be interested to know as well.
shouldberiding is offline   Reply With Quote
Old 01-01-11, 06:11 PM   #10
FastJake
Constant tinkerer
 
FastJake's Avatar
 
Join Date: May 2010
Location: Madison, Wisconsin
Bikes:
Posts: 7,577
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
Originally Posted by shouldberiding View Post
I'd be interested to know as well.
Me too. One possibility is that you could fit a reasonably wide MTB tire in a frame that was originally designed for narrower "road" tires. But then again... why not just get a mountain bike?

Without picture or specifics, I find it hard to believe you've found caliper brakes that will work.
FastJake is offline   Reply With Quote
Old 01-01-11, 06:13 PM   #11
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Rock Springs, WY
Bikes: My War
Posts: 26,860
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 302 Post(s)
I have a feeling he's just sourced some calipers that can accommodate some 2" tires, not that can actually reach a 26" rim from a 700c frame's brake bridge.
LesterOfPuppets is online now   Reply With Quote
Old 01-01-11, 06:51 PM   #12
cs1
Senior Member
 
cs1's Avatar
 
Join Date: Feb 2004
Location: Clev Oh
Bikes: Specialized, Schwinn
Posts: 6,682
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 24 Post(s)
Surly uses 26" wheels on all the LHT's under 56CM. They said the wheels are more durable and easier to find.
cs1 is online now   Reply With Quote
Old 01-01-11, 09:31 PM   #13
fuzz2050
Real Men Ride Ordinaries
 
fuzz2050's Avatar
 
Join Date: Sep 2008
Bikes:
Posts: 3,702
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Quote:
Originally Posted by cs1 View Post
Surly uses 26" wheels on all the LHT's under 56CM. They said the wheels are more durable and easier to find.
But that's neither here nor there, Surly designed the LHT's (all sizes are available now, not just the short ones) around the 26 inch wheels. That's an entirely different thing than simply sticking 26 inch wheels in a frame designed for 700c. While there are some benefits to 26 inch wheels, they are far outweighed by the trouble caused by converting a frame to a size it wasn't intended for.
fuzz2050 is offline   Reply With Quote
Old 01-02-11, 07:14 AM   #14
NightShift
Senior Member
 
Join Date: Jun 2010
Location: Las Vegas
Bikes:
Posts: 344
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I've seen 27" to 700c conversions and 26" (559mm) to 700c conversions, but I haven't seen a (non-disc) 700c to 26"(559mm) conversion, and am not sure it's feasible without modifying the frame (install canti studs or disc mounts).

Looking at the wheel diameters I do have an off the wall question of my own; if you have a bike made for 26" wheels with u-brakes and convert to cantis or Vs could you use 28"(635mm) wheels?
The size difference would be 38mm, with u-brakes reaching down 20mm and cantis extending up 20mm.
I know it's not a common wheel size, but does anyone have them? How much clearance would the frame need to have (with the skinniest available tires)?

Last edited by NightShift; 01-02-11 at 12:56 PM. Reason: Typo
NightShift is offline   Reply With Quote
Old 01-02-11, 07:36 AM   #15
NightShift
Senior Member
 
Join Date: Jun 2010
Location: Las Vegas
Bikes:
Posts: 344
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
A quick search shows tires available from Schwalbe and Kenda in the 635mm size, but only 28"x1 1/2". There may be some 26" wheel frames that could fit a 28" rim, but probably not with a 1 1/2" tire.

Don't suppose anyone makes a 635x25?
NightShift is offline   Reply With Quote
Old 01-02-11, 12:46 PM   #16
DVC45
Senior Member
 
DVC45's Avatar
 
Join Date: Dec 2006
Bikes:
Posts: 3,839
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Also consider the drop in BB height as a result of this conversion. If you're okay with that, then go ahead and keep us posted.

Thanks!
DVC45 is offline   Reply With Quote
Old 01-02-11, 12:51 PM   #17
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 20,390
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 643 Post(s)
Quote:
The Cannondale Bad Boy models are designed to use either 700C road or 26" mtb size wheels
skinny 700c and fat 26" are close in OD of wheel. but rims are Not, disc brakes let you get away with that ..

But I'll guess you cannot put Fat 29er MTB tires on those 700c rims and get them to fit in that bike..
fietsbob is offline   Reply With Quote
Old 01-04-11, 07:37 PM   #18
zzzzz
Member
Thread Starter
 
Join Date: Apr 2010
Bikes:
Posts: 41
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Hi

I am doing this because i recently bought a run down bike which I had wanted to make it my commutering bike. On closer inspection, it got dry rotted tires and a bad rim too. The rim was a 23 and it wont be practical to have a pillion on it. The most the rim can take is a 28c which is still too small.

I decided to run 26" on it because I was always curious on whether that can be done. This for the advice! you guys are a very knowledgable lot.
zzzzz is offline   Reply With Quote
Old 01-04-11, 07:56 PM   #19
zzzzz
Member
Thread Starter
 
Join Date: Apr 2010
Bikes:
Posts: 41
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Also,I got calipers, it barely fits. I could make the pads work by taking a couple of mm at the top so that it doesn't contact the side wall and the hub width didn't fit. The front seems to work. It would probably fit a 26 x 1 3/8 rim.

I bought a rear wheel and went to put 26 x 1.5. not sure if it would fit a 1.75. and used a center brake instead. Something like a band brake but works more like a car's drum brake. The stopping power I reckon would be very good.

The BB has been lowered. but will not know the extend until i mount the front wheels. thanks for the advice.


I will be getting a a front rim soon. I hope that i would work and it can be my commuter bike where I can park outside. I have other 2 bikes but I rarely ride them because here in Shanghai, bike do get missing.

Benefits to me is that smaller is more stable due to lower center of gravity( i hope) and stronger 26 vs 700c rim, its easier to get spare parts too. 26" tires tend to be thicker and lower psi and I have a lot of 26" bikes back home.


The next one I would buy would be a rod braked roadster with steel rims. Would like to find out if the 26 inches 1 3/8 steel variety would fit a 26 MTB rim with a longer 28 inches brake and if not, would the braking power be sufficient with aluminium rims.

Also, maybe coaster brakes or 3 speed hubs. I like to maintain rods as much as possible.
zzzzz is offline   Reply With Quote
Old 01-04-11, 08:23 PM   #20
DannoXYZ 
Senior Member
 
DannoXYZ's Avatar
 
Join Date: Jul 2005
Location: Saratoga, CA
Bikes:
Posts: 11,606
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Check out this Sheldon Brown - Tire Sizing website. You want to get familiar with the ISO/ETRTO tyre-sizing system. The critical dimension is the bead-seat diameter (rim overall-diameter will be slightly larger). Measure this on your existing bike, then make marks on the frame of where the new size would end up. Then you can test whether your brakes can work beforehand.
DannoXYZ is offline   Reply With Quote
Old 01-04-11, 09:00 PM   #21
LarDasse74
Guest
 
Join Date: Jul 2008
Location: Grid Reference, SK
Bikes: I never learned to ride a bike. It is my deepest shame.
Posts: 3,769
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I think the project is a solution looking for a problem. But that is just my opinion. I sincerely wish you the best and I hope you and your new 'Frankenbike' have many thousands of safe and happy miles together.

Some advice:
First, on caliper brakes, the higher up the pads are mounted in the caliper the more braking power you will have - moving the pads closer to the brake pivot changes the leverage ratio in the caliper.

Having a bike set up so it can only use filed-down brake pads is asking for trouble. In my opinion this is acceptable as a temporary measure only as it can result in the brake pad rubbing and damaging the tire if you are not careful, and it complicates maintenance.



If the brakes do not quite reach, consider making or buying drop bolts as described by Sheldon Brown.

Using a drop bolt to lower the mounting bolt allows you to have the pads higher up on the caliper so they make the correct contact with the rim, and so they are closer to the pivot and give you more power.

Generally speaking, there are three ways to correct this:
1. Have the frame modified
2. Use a drop bolt
3. Find another model or style of brake that has a longer reach
LarDasse74 is offline   Reply With Quote
Old 01-04-11, 09:18 PM   #22
zzzzz
Member
Thread Starter
 
Join Date: Apr 2010
Bikes:
Posts: 41
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
hi I managed to get the back wheel done and its running something like a band brake but works more like a car's drum brake. The front I will try the caliper and it should fit. If it doesn't, I would probably get a 700 c fork for disk mounts or a MTB fork with disc and V mounts. What would lowering the front fork affect bearing in mind that the rear has already been lowered to a 26 1.5 mtb rim with a drum brake? thanks for all the advice. 'Frankenbike' it is
zzzzz is offline   Reply With Quote
Old 01-04-11, 09:51 PM   #23
LesterOfPuppets
cowboy, steel horse, etc
 
LesterOfPuppets's Avatar
 
Join Date: Sep 2008
Location: Rock Springs, WY
Bikes: My War
Posts: 26,860
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 302 Post(s)
Drum brakes are ideal for running wrong size wheels. If they're ever available where you are, get them.
LesterOfPuppets is online now   Reply With Quote
Old 01-04-11, 10:21 PM   #24
FastJake
Constant tinkerer
 
FastJake's Avatar
 
Join Date: May 2010
Location: Madison, Wisconsin
Bikes:
Posts: 7,577
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
Originally Posted by zzzzz View Post
I bought a rear wheel and went to put 26 x 1.5. not sure if it would fit a 1.75
Quote:
Originally Posted by zzzzz View Post
The rim was a 23 and it wont be practical to have a pillion on it. The most the rim can take is a 28c which is still too small.
Some advice on tires: I've never run into a problem putting a wider tire on a narrower rim. You shouldn't go crazy, but I think you can put a 32-35c tire on pretty much any 700c rim. Just because it has a 23 now doesn't mean you can't go much wider than that. You only have to make sure they fit in your frame, and underneath your caliper brakes (if applicable.)

Quote:
Originally Posted by zzzzz View Post
What would lowering the front fork affect bearing in mind that the rear has already been lowered to a 26 1.5 mtb rim
If you want to keep the bike at its original height, consider getting a wider rear tire for your 26" MTB rim. I have MTB tires 1.95" wide that are the same diameter as a 700x23c or 25c. Just something to think about.


One other thing: pictures would help a lot. You're throwing around a lot of tire sizes and options, and sometimes I don't know exactly what you're trying to do. Plus I'm curious to see your Frankenbike

Last edited by FastJake; 01-04-11 at 10:27 PM.
FastJake is offline   Reply With Quote
Old 01-04-11, 10:24 PM   #25
zzzzz
Member
Thread Starter
 
Join Date: Apr 2010
Bikes:
Posts: 41
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
yes, i had considered welding a 5mm steel onto the rear frame so that I can mount the rear caliper if all else fails, good thing i din not have to do it that way. Will take a picture of the bike when completed. drum brakes are great and a cheaper alternative to disc. will have to try if the front wheel 26" works.
zzzzz is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 05:43 PM.