Bicycle Mechanics - Is it possible to put a 700c wheel on a bike that had 27" wheels?

i have an older road bike with some 27" wheels that need to be replaced, I was wondering if i could put 700c wheels on this bike with no problems... I have 700c wheels from another bike and was looking to avoid buying new 27"

Definitely maybe, possibly probably not.

Depends on how tight the geometry is on the frame, how long the fork is, etc. The issue is how far the brake calipers will reach. Some tightly-designed frames can be swapped to 700s with the addition of long-reach brake calipers, and some need long-reach calipers to reach the 27" rims. Got a picture? Straight-on shots of the front and back brake calipers, with the wheels installed, would be ideal.

I run a 700 front wheel on my '86 Schwinn Traveler (the original 27 wheel that came on the bike is slighter greater in diameter than a 700), the design of the brakes allowed for the movement of the brake pads to work with the 700. You might just want to try out what you got and see if it fits.

Definitely maybe, possibly probably not.

Depends on how tight the geometry is on the frame, how long the fork is, etc. The issue is how far the brake calipers will reach. Some tightly-designed frames can be swapped to 700s with the addition of long-reach brake calipers, and some need long-reach calipers to reach the 27" rims. Got a picture? Straight-on shots of the front and back brake calipers, with the wheels installed, would be ideal.

Basically you need to be able to move the brake shoes 4 millimeters lower in the caliper slots, so they will squeeze on the 700c rim instead of the tire. If your calipers are long enough to allow that, you're golden. If not, you'll need to get some longer-armed calipers. Remember the 700c rim is actually smaller than the 27 inch rim, by 8 mm in terms of diameter.

I run a 700 front wheel on my '86 Schwinn Traveler (the original 27 wheel that came on the bike is slighter greater in diameter than a 700), the design of the brakes allowed for the movement of the brake pads to work with the 700. You might just want to try out what you got and see if it fits.

+1 It might be a good idea to look into long reach dual-pivot calipers. Tektro has a few to choose from. Kool Stop salmon pads are also a good upgrade. I made this switch on my Schwinn World Tourer, but realized that the drivetrain was unique (Shimano that has freewheel built into the bottom bracket vs rear wheel hub), so ended up putting the 27" wheels back on with new tires. Left the Tektro dual-pivot brakes w/KS salmon pads, though.:thumb:

The thing I found with the KS salmon pads is that they leave MUCH less debris on the rims than Shimano and other brands of pads I had tried. It gets old having to clean that detritus off the rims! Now I do a 'start-of-season' and 'end of season' check of rims/pads, and have a lot less cleaning to do!

P.S. Those 27" wheels are STEEL by the way, so the KS salmon pads were a 'must' in my mind. I know, I know, my mind aint what it used to be, but I thought it might be important to be able to stop if I needed to.:innocent:

iput 700c on my 83 nishik century with it's original diacompe brakes with no issues, just a pad adjustment. If your bike has those old school brake block style of pads you will probably want to go with a modern brake pad for better stopping power. I have a combo of the salmon/black pad on my bikes and they do stop much better for me.

I have 700c wheels from another bike and was looking to avoid buying new 27"

So test fit the 700c wheels that you already own and see for sure exactly what you are going to run into.

Yes its possible, 27" wheels have an ISO of 630mm, and 700c have an ISO of 622mm. So the rim is smaller by 8mm in Diameter or 4mm in Radius, so there is a chance your calipers will reach the extra 4mm. If not you can get long reach calipers, such as shimano br-600 or br-a550 for $15-$30 each

also your pedal could be 4mm lower this might not seem much but there is a possible pedal strike on steep turns if ridden as fixed gear please note of this.

i had 3 different bike shops tell me i would need to buy new brakes if i wanted to switch from 27 to 700. i didn't have access to any 700s to try at the time. turns out they were ALL wrong.

just try it and see

i have an older road bike with some 27" wheels that need to be replaced, I was wondering if i could put 700c wheels on this bike with no problems... I have 700c wheels from another bike and was looking to avoid buying new 27"

You say you have an older bike. You might want to check the spacing between the rear wheel dropouts to see if they match with the current standard of 130mm (5.12"). Some older bikes, depending on their age, might have less so it might pay to measure first. Not to say that the frame couldn't be "adjusted" to work but it is something to consider.

+1 , the dropout issue
over the years rear wheel axle widths have widened, so the dropout spread had to follow,
to make room, as the # of 'speeds' were added..
... 5, 120,.. 6/7 , 126 ... 8, 9, 10 ,11 road , 130 & mountain bikes 135mm ..

Since you already have the wheels just give them a try if the frame is steel. If aluminum or Carbon don't try this. Most steel frames can accommodate one size up (ex 126mm spacing to 130mm) without having to cold set frame. You might decide to cold set latter, but for now it won't do any harm it just might require a little extra effort to get the wheel in. If the brake pads contact the rim correctly your golden. If they get close lets say 1 to 2 mm short a small round file can be used to extend the slot on many calipers. Just make sure you don't remove any great amount of material as this can weaken things. Its a judgment call. If your brakes are pricey collectibles I would go ahead and just buy long reach calipers.

The 4mm you loose can cause pedal strikes. Not common but not unheard off. Usually the result of a bike with long crank arms and little clearance to begin with. Doing some testing at low speeds would not be unwise.

The pedal strike issue is really just a matter of inherent clearances and how hard you ride, and you're the only one who can assess that. The lateral clearance WILL be less, but that really might not be a problem. A lot of well-respected 700c racing bikes have BB drops between 7 and 8 cm even with 175 mm cranks AND with narrower tires that have smaller radii.

Another significant factor is whether you will use wide old school rattrap touring pedals, much narrower old school road pedals like the old Campagnolo Record Strada (or Pista, for that matter), or a clipless pedal with a really small platform, like maybe a Crank Bros or an Eggbeater. I'd bet the difference in width between these pedals is a lot more significant in lean safety than the 4 mm difference in rim radius.

And even if the clearance is compromised, if you ride road non-competitvely you can learn to raise the inside pedal as you corner, not pedaling through corners.

I've had no problem with two older French bikes in going to 700c, but these were relatively tight geometry "racing" frames. Now, I have an even older British frame built for 27" wheels + fenders, and the reach is really long.

To complicate things, I have really been wanting to do a 650B conversion to get the really big fat tires. But, with my frame that was originally built for 27" wheels & fenders, the reach may simply be too long for a 650B wheel.

http://i120.photobucket.com/albums/o191/LeicaLad/IMG_2368.jpg

This is a 700c wheel and Zeus calipers.

From my ballpark measurements, it may take a 72-73mm reach brake to fit a 700c wheel in there. I don't have a 650B wheel to try (although I'm looking in the NoVa area!), although given the reach needs of a 700c wheel, it looks very dubious that a 650B wheel will be a viable option.

My original hope was to run a 650B wheelset with 42mm Grand Bois Hetre tires.

My question is: If a 650B wheel is not an option on this frame, does a fat 700c, say 35mm, at least approximate the ride of a 650B 42mm? How would it be that different (in subjective terms)?

I'd consider hunting for ultra-long reach brakes, but I suspect that if a reach that extreme is required, it just isn't going to look right nor feel right, either riding or braking.

Comments and advice sincerely sought.

Thank you.

... I have really been wanting to do a 650B conversion to get the really big fat tires. But, with my frame that was originally built for 27" wheels & fenders, the reach may simply be too long for a 650B wheel.

One option(which actually is easier if the reach is way off) is to use what Sheldon Brown calls a drop bolt. It's basically a tab with two holes in it. One hole allows it to be bolted to the fork crown/brake bridge, the other hole is used to attach the brake to the tab.

But I've also seen pictures of someone doing same thing to the brake arms, to drop the brake pads even lower. That guy claimed that it worked OK, but YMMV.

700C wheels can fit a 27" wheeled frame in 99.9& of the time. I worked at a high end bike shop in the late 70's early 80's and did the conversion many times. On about 5% of the bikes I had to file the brakes a few mm to get the shoes to drop all the way. I've never seen a single bike that couldn't be changed with the original brakes. 4mm is less than 1/6"....

Hmmm. Well, that photo above clearly shows one of the 0.1%. I couldn't file those brake enough to reach those 700c wheels.

Hmmm. Well, that photo above clearly shows one of the 0.1%. I couldn't file those brake enough to reach those 700c wheels.

Agreed, it's strange to see the shoes all the way down on any frame with the wheels the frame was designed for, what brand/application is that frame? By the 80's most low and medium cost frames/bikes could take both as the market switched over from 27" to 700c. Racing/Sport bikes with close reach brakes and 700C wheels are a different case. Those frames can have issues with 27" wheels due to lack of clearence.

Okay, to be clear, this frame was designed for 27" wheels + fenders. It's my 1963 Hetchins Mountain King.

What you see is a 700c wheel in the fork. Big drop problem moving from 27" to 700c. Long reach brakes would do, but I'm still wanting to put a 650B wheel in there to see just how far the reach would have to be. And if ANY brake would have that kind of reach. The question of (width) clearing a 42mm tire is another issue.

One option(which actually is easier if the reach is way off) is to use what Sheldon Brown calls a drop bolt. It's basically a tab with two holes in it. One hole allows it to be bolted to the fork crown/brake bridge, the other hole is used to attach the brake to the tab.

But I've also seen pictures of someone doing same thing to the brake arms, to drop the brake pads even lower. That guy claimed that it worked OK, but YMMV.

A drop bolt to bring the caliper closer to the wheel is probably the best bet. Lengthening the brake arms further in a similar manner is going to effect the amount of stopping power you have by changing the fulcrum of the brake.

A drop bolt to bring the caliper closer to the wheel is probably the best bet. Lengthening the brake arms further in a similar manner is going to effect the amount of stopping power you have by changing the fulcrum of the brake.

Exactly. Good point to worry about. Unfortunately, the drop bolts are now amazingly pricey – when you can find them.

OR, I give up on the 650B idea. sigh.


p.s. - I like your Burke quote!

If you have relatively low cost calipers you can just extend-rat tail file- the slots a bit if they are a mm or so short.
Usually you can do this switch easy enough on older bikes with no filing at all.
Charlie

Well, Mr. IGH already made that observation above. And we have an example here where that obviously won't work.

Anybody know a source for reasonably priced drop-bolts?

http://www.sheldonbrown.com/home-drop.html

Material costs only. You should be able to find all the needed parts at Home Depot or Tractor Supply.

OMG, is that ugly. If I had a true beater frame that needed this, maybe. For the Hetchins? I don't think so.

Those "no longer available" drop-bolts one the page linked from the first one sure are nice. Shame they're gone.

http://www.amazon.com/Tektro-C326-Caliper-Brake-Black/dp/B0041X5XR2/ref=sr_1_29?ie=UTF8&s=sporting-goods&qid=1287613350&sr=1-29

Tektro C326 Caliper Brake Pair Black



Product Features

Dual pivot caliper brake
For use with 38mm to 50mm wide rims and 2.125" tires
79mm to 99mm reach

...My question is: If a 650B wheel is not an option on this frame, does a fat 700c, say 35mm, at least approximate the ride of a 650B 42mm? How would it be that different (in subjective terms)?...

I'm running Mavic A319s with 35mm tires @ 60psi. Rides sooooo sweet, lots of tire choices, no premium for exotic sizes with limited choices. Great on crushed gravel, pothole laced streets and smooth asphalt MUPs:

http://images2.snapfish.com/232323232%7Ffp537%3B5%3Enu%3D3275%3E4%3B3%3E733%3EWSNRCG%3D3497%3A%3B%3C29332%3Anu0mrj

http://images2.snapfish.com/232323232%7Ffp538%3A9%3Enu%3D3275%3E4%3B3%3E733%3EWSNRCG%3D3497%3A%3B%3C28932%3Anu0mrj

I did this on my 80's Peugeot which was apparently designed for 27's with fenders and motorcycle tires. I just mounted some BMX calipers on it, which had an extra-long 85mm reach. Ugly as sin, but I found them in a swap meet bin for $2 so you can't beat that.

Wow! Those Tektro's are loooong. I'd been looking at the R556/R559, but hadn't seen these. Hmm. Good price, too.

Interesting. I gotta find me a 650B wheel to try. I know there's a LBS on the other side of the city (call that 50miles) that has 'em. Guess I'm looking at a drive. I think mounting wheels and eyeballing is my only way to really make the call.

Thanks, again, guys!

Sorry missed MR IGH
Those calipers look awfully modern-not original to the frame?

If looking for the cheapest no cost way I would file them down 2mm, and them shave the tops of those shoes/pads.
If looks like it is maybe 4-5 mm too short. Those couldn't be the original calipers.
When looking for a no cost solution, you frequently have to compromise a bit.
The longer reach calipers are the cheapest "good way" to do it.
There isn't a free (except for labor) "good way" but there is a "maybe it will work" way.

Get out a file, then grind the top of the pads/shoes

You can also shim the shoe so it points a bit downward. You will have to reface/cut/grind the braking material so it is more or less flush with the rim.

This is am awful lot of work-

Sorry missed MR IGH...Those calipers look awfully modern-not original to the frame?

No need to be sorry, it's not as if my Mom made 'em, just trying to point out options. For long reach vintage look I like Weimann sidepulls. I run the 730's on a few bikes, there's 820 and 1080, that's 73mm, 82mm, 108mm drop respectively. The 730s come on Schwinn 27" Varsities and Suburbans, the 820s come on Collegites and 3 speed 26" Schwinns. The 1080s come on Typhoon style and Stingray style Schwinn.

http://images2.snapfish.com/232323232%7Ffp538%3B4%3Enu%3D3275%3E4%3B3%3E733%3EWSNRCG%3D355237689232%3Anu0mrj

I've had no problem with two older French bikes in going to 700c, but these were relatively tight geometry "racing" frames. Now, I have an even older British frame built for 27" wheels + fenders, and the reach is really long.

To complicate things, I have really been wanting to do a 650B conversion to get the really big fat tires. But, with my frame that was originally built for 27" wheels & fenders, the reach may simply be too long for a 650B wheel.

This is a 700c wheel and Zeus calipers.

From my ballpark measurements, it may take a 72-73mm reach brake to fit a 700c wheel in there. I don't have a 650B wheel to try (although I'm looking in the NoVa area!), although given the reach needs of a 700c wheel, it looks very dubious that a 650B wheel will be a viable option.

My original hope was to run a 650B wheelset with 42mm Grand Bois Hetre tires.

My question is: If a 650B wheel is not an option on this frame, does a fat 700c, say 35mm, at least approximate the ride of a 650B 42mm? How would it be that different (in subjective terms)?

I'd consider hunting for ultra-long reach brakes, but I suspect that if a reach that extreme is required, it just isn't going to look right nor feel right, either riding or braking.

Comments and advice sincerely sought.

Thank you.

You probably won't want to run 650b on that frame, as it already has lots of clearance, and converting to 650b will likely drop your BB dangerously low.

As other members mentioned, running fat 700c tires is pretty awesome, and you'd have way more choices for the rubber. I was about to convert an old tight-clearance 700c fuji, but in the end, i couldn't stomach the limited tire selection. So, i sold it. =) gonna build a 700c frame with the clearances i want, but back to your frame: that hetchins is almost too nice to play frankenstein with, but it is your bike. Get some longer-reach calipers, a nice 700c wheelset, and the 35mm version of your favorite tire. hold onto all the old stuff, though, in case you ever get sentimental or want to sell the bike.

-rob

I'm running Mavic A319s with 35mm tires @ 60psi. Rides sooooo sweet, lots of tire choices, no premium for exotic sizes with limited choices. Great on crushed gravel, pothole laced streets and smooth asphalt MUPs:

http://images2.snapfish.com/232323232%7Ffp537%3B5%3Enu%3D3275%3E4%3B3%3E733%3EWSNRCG%3D3497%3A%3B%3C29332%3Anu0mrj

http://images2.snapfish.com/232323232%7Ffp538%3A9%3Enu%3D3275%3E4%3B3%3E733%3EWSNRCG%3D3497%3A%3B%3C28932%3Anu0mrj

Hey, brother-- where's your lights at? That front hub is probably dying of boredom; give it a chance to do it's thing.

-rob

Leicalad, if you're after 650b's with wide 42'ish mm tires then you may as well just go with 26 inch MTB wheels and 1.5 inch road slicks. A far wider variety at your fingertips.

But even so this will drop the height of the bike. 700c's with 25mm tires are about 3/8 to 1/2 inch more in diameter than 26's with 2.25 inch knobbie tires are in overall tread diameter. I know this because I did a conversion the other way around to make a mountain bike into a high performance disc brake hybrid back before there was such an animal. Of course these days there's literally dozens of such models to choose from.

In any event a drop bolt sort of thing for 27 to 700c is one thing but the reach to get down to a 650 or MTB rim is a whole other issue. The torque from the braking and the arm and drop bolt extension distance from the fork crown area to the rim is almost certain to produce squealing conditions. And if nothing else the distance needed makes such an arrangement weaker than I would want to trust. At the rear it's even worse since now you're torquing on that steat stay bridge tube and joints with a lot more leverage arm length. All in all it would be rediculously kludgey looking to use rim brakes in that way.

If you're that keen on the idea then kick in for the cost of having canti posts brased on and for a new paintjob. That would be the optimum way to go. But before you do this measure the tire tread diameters. If you're going from a 27 inch original (it's not fair to measure the "upgraded" 700c tire in this case) to a 650b even with a fat tire it's a helluva drop at the BB and cranks. You're seriously aiming for a lot of pedal strikes in much of any sort of lean angle.

Ditch the 650b idea, totally unnecessary . I'm 235 lbs and just put.some 700 x 35c tires on my commuter up from 28s I was running. Night and day difference in comfort and I out cuclocross tires on so I can hit dirt trails with ease. Other option is just buy some new cheap 27" aluminum wheels. Aebike.com has them for.30 bucks each.

Deep sigh.

I'm beginning to think the multitude of voices saying "Forget 650B" may, sadly, be correct. The drop really looks severe. I still might try to track if one of the LBSs has a set of 650B wheels to just see. BUT, fat 700c may be the right option. There will still be plenty of room for fenders. The rear stays have amazingly wide clearance, both top & bottom.

The calipers in that photo are Zeus 2000. A set I pulled off a PX-10 I sold earlier this summer. From what I can see, there simply isn't adequate material to file down to fit, and still have them trustworthy. No sweat, they can return to my parts box for something in the future.

I'm the second owner of this Hetchins. The frame was totally refurb'd, re-chromed & repainted, so it looks utterly brand new. (It's really, really beautiful!). So I ain't doing no brazing. The original owner has no memory of the original set-up, as he changed bits and pieces frequently over the years. It was even his "winter bike" for a few years prior to the refurb.

http://i120.photobucket.com/albums/o191/LeicaLad/fullsideview.jpg

The BB drop/height is relatively high on this model to begin with, so the drop in moving to smaller sizes is not as problematic as on many 27"-specific frames. Also, with 42mm tires, who's racing?

Still, I'm thinking that 700c with 35+ tires (Panacela has Tour Guards at 35mm, I think) may be the right option. I'll still need new brakes, but the options open up. The several Tektro models don't look bad. The R556/R559 are growing on me. As this is a 1963 frame, going "period correct" just isn't a realistic option. I do have a lot of 70's & 80's bit and pieces, so I'll honor the classic nature, but in spirit only.

Brooks saddle, Campy levers, Rally derailleur, Record FD, Stronglight 93 crankset, etc. I have a set of Campy High Flange wheels, but I'm not exactly thrilled with the races on them, so I'm still waffling whether to use them 'cause they look the best, or to go with orphan/mismatched-but NOS hubs for better rolling.

I'm also into Clyde territory in size, so I appreciate the report on experience in larger 700c tires.

All the comments and advice are appreciated, gentlemen. Thanks!

That's a beautiful looking classic frame. And a classic of this sort deserves to be built up faithful to the manner of the original. I'd say 700c with 28's or 32's, Honjo or other really nice fenders and some long enough reach Tektro double pivots. Up top a set of aero levers and bar end shifters or brifters would complete the makeup of this frame in a manner faithful to its roots and would be a superb bike to ride.

I don't know what conditions you're riding in that make you think you NEED the fattest tires out there but I can say from experience that even 25's survive in most city environments if you're at all carefull about picking your path to avoid the tank trap sized potholes. But then even with 35's you really don't want to hit things that are THAT big either.

25's and even 23's will work fine, however as a clyde if you want some degree of comfort than yes you should be looking at no smaller than 28's and 32 - 35 is probably the sweetspot with anything over that truly being overkill. Get a mtb at that point.

Thank you, gentlemen.

I was wanting to do something a bit different, but obviously not something that was irreversible.

I'll be using Campy brake levers and downtube shifters, just 'cause I've got 'em in my parts box. The only other option would be upright bars and thumb shifters, just 'cause I got those in my parts collections from a prior mixte project for the Mrs.

I generally ride 28mm 700c on my other current rider. As an aging Clyde, I don't see myself going skinny tires again. I do still have my old TDF set up with 23m, but it's not getting much riding time, either.

If not 28, then I think I ought to go, at least, to 35mm. Just to know the experience. It was the idea of the 42mm Grand Bois Hetre tires that had inspired me to consider 650B. The Panaracer TG at 35 is my "fallback" position.

As for MTBs: My 1981 Ritchey mtb was stolen a couple years back. I'm still in mourning.

That's a beautiful looking classic frame. And a classic of this sort deserves to be built up faithful to the manner of the original. I'd say 700c with 28's or 32's, Honjo or other really nice fenders and some long enough reach Tektro double pivots. Up top a set of aero levers and bar end shifters or brifters would complete the makeup of this frame in a manner faithful to its roots and would be a superb bike to ride.
.

This is some nice advice, but i reckon we have different definitions of the term "faithful". To leicalad, panaracer makes pasela TGs in 35s and in 32s. IME, the sidewalls of paselas don't hold up to hefty riders like myself, unless you're extremely diligent with keeping the air up. Even then, they're sketchy...

hth,
-rob

I understood that this was a problem with older panaracer TGs, but I thought that the current versions were better. No?

What other tires at the 35mm size have you found to hold up better (for the bigger rider)?

It sure seems like a shame to mess up the vintage period on such a nicely-restored frame... it's a bummer there isn't a make of dual-pivot with retro aesthetics.

I'd try to find a period single-pivot to reach the rear, and only put one of those Tektros on the front... you could etch off the anodising and drill some countersunk lightening holes or something in it, I guess ; )