Bicycle Mechanics - 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?

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?


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.

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

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.

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.

can i convert a 700c bike to mtb wheels?

The Cannondale Bad Boy (http://www.cannondale.com/usa/usaeng/Products/Bikes/Recreation-Urban/Urban/Bad-Boy/) models are designed to use either 700C road or 26" mtb size wheels.

The Cannondale Bad Boy (http://www.cannondale.com/usa/usaeng/Products/Bikes/Recreation-Urban/Urban/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.

You can run 26" on pretty much any disc equipped 29er if you really wanted to.

Why are you doing this?

I'd be interested to know as well.

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.

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.

Surly uses 26" wheels on all the LHT's under 56CM. They said the wheels are more durable and easier to find.

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.

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)?

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?

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!

The Cannondale Bad Boy (http://www.cannondale.com/usa/usaeng/Products/Bikes/Recreation-Urban/Urban/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..

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.

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.

Check out this Sheldon Brown - Tire Sizing (http://www.sheldonbrown.com/tire-sizing.html) 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.
http://www.sheldonbrown.com/images/bead-seat-diameter.jpg

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 (http://sheldonbrown.com/home-drop.html).

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

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 :)

Drum brakes are ideal for running wrong size wheels. If they're ever available where you are, get them.

I bought a rear wheel and went to put 26 x 1.5. not sure if it would fit a 1.75


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.)


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 :)

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.

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.)
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 :)

Its stated on the rims as 23 - 28. I took it to mean nothing bigger. the internal width is 18mm. I bought another set of rims via mail and it was 19mm.

I am unfamiliar with 700c tires and sizings. Another reason why i sticked to 26 is that I needed to change a larger 700c tire, tube and damaged rims and maybe even spokes and I am not sure if the project works and for the front too.

If it doesn't, I got these parts that i have no use for. 26" is different, the rest of my bikes back home are all 26.

Please dont get your hopes too high regarding Frankenbike, I gotten it for 18.20 USD and stll it isnt a good buy. Its was a buy first then think kind of thing. I am glad the rear wheel is done. I could not stop thinking about how to settle that. LOL

If you're replacing the front fork you could try for a suspension corrected 26" fork.
Suspension corrected forks are taller axle to crown. They're intended to maintain a bikes geometry when switching from suspension to rigid. If anything these will be taller than you want.

Just check the axle to crown measure of the current fork, measure the radius of the old wheel with tire, measure the radius of the new wheel with tire, subtract the new from the old, and the difference to the a to c of the current fork, and that will give you the a to c you want for the new fork.

You may want to use a fork with less rake and slightly more than equivalent a to c.
I'm sure there are others here more qualified to make recommendations about geometry, but any useful recommendations will require more info.

Switching the fork and using a drum brake is a creative solution. I hadn't considered that option.

Best of luck. If possible please post pictures.

If you give your location there may be a BFer near you who would give you a fork from their parts pile.
I have 2 rigid (not tall/suspension corrected) 26" forks with 1" steerer tube, 1 60mm travel suspension fork with 1" steer tube, 1 80mm travel suspension fork with 1 1/8" steer tube, and 1 rigid fork with 1 1/8" steer tube.

If you happen to be near Vegas I'd give you one of the 1" steerer forks or trade you one of the 1 1/8" 26" forks for the 700c fork.

Hi I'm am currently in shanghai right now, all these bikes would be sold or given when I get deposted. So its hard to get 700 parts and local bike shops rarely stock them and if they do, its at a premium.

For the front, I can probably get the brakes to fit on it with a 26" MTB without changing fork or I can change it so that it can accomodate a 26 * 2.3 tire. Theres probably many options in front. I am thinking which is the cheapest to do.

Was initially thinking of fitting a 700 * 45c tire to the front.

96'er conversions typically and a 29"/700c to the front of a 26" wheeled frame, but if you have a working rear brake and the bb is high enough I don't see any reason you can't do it this way.

Is there clearance for a 622x45?

If the reason for the 700c to 26" conversion is availability of parts you may want to go ahead and change the front with the back. When a wheel size is in short supply, in my experience, you end up with more trouble finding tires and tubes and end up paying more for them. I would at least check if a suitable fork is available, what the cost of the fork would be, and what the difference in costs for the tires would be.

Also don't forget that these changes will effect the geometry. If the front tire is replaced with a taller tire (I don't know what it came with, so I'm just guessing on this) and the rear is lowered you'll have more slack seat tube and head tube angles. This will probably mean a more upright riding position and more sluggish steering.
If you were converting a "road" bike to an urban city bike that would probably be a good thing, but if the frame has clearance for a 622x45 tire and a high enough bb to accommodate the change to 26" I'm guessing it's not a typical road bike. Is it a CX frame? A 29'er?

Using a taller 26" fork with less rake would still change the tube angles, but the difference in rake would help keep the steering from being to sluggish. It would also keep you from carrying two different size tubes, and if you'll be posted there long enough to need a second set of tires it would simplify matters there.

If the 700c in front works for you I don't see anything inherently wrong with that, I'm just trying to give food for thought.

thanks, its a road bike with skinny tires. appreciate your advice. think i should stick with 26 and not try the weird sizes. 23 * 700 is quite rare here. 700 * 45, I can forget about getting a tube from the local shops.

the usual sizes here are
28 1/2 roadster
26 mtb
26 1 3/8
24 mtb

I am looking for a more relaxed ride and there might not even be clearance for 45c. I think I better give up that idea.


Would like to share the way I discourage theft on an old commuter bike, a bit drastic and the lock is easily opened.
the heavy U lock I sometimes use over here. Look at the diameter compared to the AA size batt and incase it gets stolen, check out the department store bikes.

Maybe your best bet is to get a pet pitbull and leash him to your bike when it's parked.... :D

I really like 26x1 3/8. It's one of the sizes that's hard to find here. My options seem to be have them shipped from Asia, buy wheelchair tires (making sure they have the tread centered, most the performance tires have the tread offset), or get them from Walmart (not kidding, most convenient source). For wheels I can pay for custom build or find an old bike that has them (invariably chromed steel rims).

If it wasn't for the cost of shipping I would love to trade parts readily available here for parts readily available there.

...checking shipping cost...

Any reason why do you like that size? I have fixed a front 26 wheel and it fits. Both are now 1.5 slicks and i try to see if 1.75 fits if i can get slicks that size. My 1.95 slick would not fit. The BB bearing is shot and I am short of grease, it is disassembled. Will take a picture of the bike when the crank is up.

Maybe your best bet is to get a pet pitbull and leash him to your bike when it's parked.... :D

:lol: i try to discourage theft by giving a bad paint job. I have seen many bikes lock onto themself here. They can be carried off. I nearly had my electric scooter stolen here. They tried to push it and it only had its back wheel and steering locked.

After that, i locked the front and installed alarms.

The Cannondale Bad Boy (http://www.cannondale.com/usa/usaeng/Products/Bikes/Recreation-Urban/Urban/Bad-Boy/) models are designed to use either 700C road or 26" mtb size wheels.

But they're also disc brake which simplifies things.

my road bike doesn't have the disc mounts.

my road bike doesn't have the disc mounts.

Yeah I read. Sucks to be you :) Wheel switches can be a beast if the design isn't there to help.

wait till I tell you about the stuck seatpost and stem. I think I would just leave it as an antitheft accessory. Ok, I admit... its too much trouble. :)

Once its ready, I'm eyeing this bike. Like the classic look but I hear the braking is lousy. Like to keep the rods for looks.

wondering how would it look if I were to install disc in front but keeping the fork and wheel? contradictory?

I like the 26x1 3/8" (590mm) wheel size because I have short legs. I have a compact geometry hybrid with 700c wheels that fits ok, but classic geometry/horizontal toptube isn't an option. There are plenty of 700c road bikes made for riders with legs as short or shorter than mine (31.5" bike inseam, 29" pants inseam), but they're made for short riders. I'm 6'1".
Some of the old 26x1 3/8" bikes have good standover height and a good toptube length. With a longer stem I get a better fit on an old 26" road bike than on almost any new bike (excluding custom).
The one I've been riding for the past couple years also has 165mm crank arms (much more common one these bikes, if you don't mind one piece cranks) which makes it MUCH easier for me to maintain a high cadence.

A while back there had been a push for 650b wheels for touring and commuter bikes. If you're interested in the advantages of smaller wheels and converting to smaller wheels do a search for 650b.

My only problem with 650b is cost (which, for good quality, is also an issue with 650a) and the fact that 650a was already a more pervasive standard (for older bikes and wheelchairs).

....wondering how would it look if I were to install disc in front but keeping the fork and wheel?

That would be a bit of a challenge. You'd have to add caliper mounts to the fork (doable, but likely to cost you some unless you're able to DIY. if nothing else it'll mess up the paintjob). Setting up a disc brake for rod actuation would be another hurdle. And while I'm reasonably certain that you can find a disc brake hub to lace your current rim to I'm equally certain that buying a whole new disc brake wheel would be cheaper.

On a side note, getting rid of rod actuated brakes is often seen as a milestone in the early evolution of cars. Not that a bike it entirely comparable, but still.

Hi

this are the pictures as promised. The brake lines have been cut since the picture and the rear brake have been changed to a lockable version. It was bought in a bad state and the BB bearings had even disintegrated. All have been serviced and a new BB installed, handles, seats etc.

That looks fine as long as you don't expect a lot of braking power or the ability to pedal unless perfectly upright.

I have tried cycling once but have not tried to see if the pedals were too low. If it it, will either have to ride like im on a coaster braked bike or change the frame to a MTB.

You are right, the front braking is mediocre but the rear brake is outstanding. I used to use this style of brake with an electric bike of 24inches wheel and with a pillion I was able to lock the back wheel and thats about 300lbs. Hope that it would supplement the weak front braking.

On a side note, getting rid of rod actuated brakes is often seen as a milestone in the early evolution of cars. Not that a bike it entirely comparable, but still.

Thanks, will keep that in mind.

I have one of these conversions. 270976 Used a small bmx crank to fix the clearance problem but am still working on the brakes, only front disc for now, will proly buy A2Z disc bracket for the rear...only $40 and quick fix to the brake and smaller wheel problem.

It's great to see people's projects and how they get things to work.

I would however, ask the cost of the parts and the original bike? could you have bought a 26" wheel bike and just rode it for the same money?
Craigslist is your friend...

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.

Exactly. Thread/ (pretty much).

I have one of these conversions. 270976 Used a small bmx crank to fix the clearance problem but am still working on the brakes, only front disc for now, will proly buy A2Z disc bracket for the rear...only $40 and quick fix to the brake and smaller wheel problem.

I was thinking about those A2Z disk adapters, but you have to be very careful whether they will work with your dropouts and hub.