pashlit

Hello folks,
Quick question. Sorry if its been asked 1000 times already. I am just a beginner in road riding.
I am thinking of doing cyclrocorss cycling. My first option is to buy a totally new cyclocross bike. But I can also go cheaper way and just buy a second set of wheels for my road bike. I know road bike is not really cyclocross but I am not going to ride/race it on really harsh pavement anyway. So the question I have is what wheels will do it? How wide does the rim should be? And do I need anything else to perform that task?
Thanks.

rebel1916

Wheels, knobbies and mud will almost certainly present clearance issues. Likely insurmountable. Do you have an MTB?

Continuity

Just some sturdy rims, some tyres with a bit of tread on them, and maybe some low-profile canti brakes, and you should be good to go.

Here's ChainReaction's 'cyclocross wheels' current selection - they do some quite nice looking stuff that starts at really reasonable prices IMO.

Some of those 'cyclocross' wheels look like they'd be fantastic for commuter duty actually - hmm....

pashlit

I do have MTB. Cannodale Scalpel 1000. Awesome bike and super fast and light, but I will probably be selling it. Really want to get Cyclocross.

Wilfred Laurier

This is a very uninformed response. Road frames and forks will almost never fit tires with any tread. Also, you cannot simply bolt on cantilever brakes to a frame that was not designed for them.

The correct answer is: because of clearance issues, it is difficult to fit cyclocross tires into a road frame and fork. If you convert to 650B size wheelsand get some long reach brakes it might work, but that is not simply a matter of swapping wheels.
In reality, added clearance for wider tires and mud, and brakes, are the two main differences between road and CX bikes.

ThermionicScott 

What kind of a road bike do you have? Most newer ones won't have clearance for the tires you'll want, and the caliper brakes will load up with mud right away.

pashlit

Ahhh.... I kinda expected that. So the best choice is to buy a CX bike. Well... My Scalpel is definetelly for sale then. My road bike is Canndondale 2010 CAAD8 with simple 2300 set up.

Continuity

Ahh, reading back, I completely agree. I was somehow under the impression that the OP had examined his road frame and saw that it was of the type with the needed clearance and mounting points for conversion.

Other than *that* - I couldn't see any problem.

dddd

A lot of the old road frames like PX-10's and the like were used for cyclocross, but the 1980's ushered in Italian-style shorter fork blades, steeper frame angles and tight clearances atop the tires.

I have no idea how your CAAD8 is configured, but with road tires you would want to see a good 1/2" at minimum for dealing with a thin CX tire and even a hint of mud.

CX here in CA is mostly dry, but one would still want to research their frame's steering head angle and avoid any frame with much more than 72 degrees or so. A road frame with a long stem might have you tipping foreward every time you hade to brake for the barriers, and a steep head tube angle would make this even worse. These were insurmountable problems with me racing on my Windor Profesional, but my Miyata Touring bike worked really well after only removing the rear rack and luggage. This touring bike has the shallower frame angles and clearance needed for cyclocross here in CA.

Continuity

*Nice* Miyata!

MileHighMark

Are you simply looking to explore dirt roads/trails? If so, install the fattest/widest tires that your road bike can accommodate.

pashlit

I was thinking about that too, but the max I could get is 25 I guess. And Ideally I d like to have both setups, so I could quickly swap them. Second bike would solve all the issues , but thats more $$$$. Hard to find anything good for around 800-900 bucks. I cant spend more on the second bike...Well 3rd bike

MileHighMark

Toss some 25s on the Cannondale and give it a try. As long as you're not looking at overly rocky or loose conditions, you'd be surprised at how well regular road bikes perform.

caloso

I did my first season of CX by jamming the biggest tires I could fit into an old Trek 660. They were Kenda Kwick labeled as 30mm, but they really were more like 28mm. This arrangement worked fine for the dusty races in September, not so fine for the muddy races in November. So much mud and grass jammed into the calipers that I had to stop several times a lap to clear it out.

pashlit

So, the question arises. How can I actually find the biggest tire size I could fit on my RIMs? 25 will probably work. But what about real CX tires like 28 for example? And if you could also give me some suggestions on what tires to look in, I d appreciate that. I m just going to do some gravel trail road here. Not going to climb mountain on that thing so far.

pierce

beginners CX race classes often race flat bar mountain bikes. you want a simple light hard tail mountain bike with relatively light tires for this. they graduate to CX specific drop bar bikes in the "A" classes

pierce

measure the clearance between your existing 25mm tires at the closest point(s) to the frame (probably by the chain stays). double the smallest of these measurements. subtract 4 or 6mm, and add difference to 25mm, and thats about the fattest tire you can run, with 2-3mm clearance at that tightest spot. you need 2-3mm or wheel and frame flex will have you scraping the wheel. also, some tires are 1-2mm narrower or wider than they claim.

Wilfred Laurier

https://sheldonbrown.com/tire-sizing.html

Down toward the bottom of this page there is a chart with reccomended tire widths for various rim widths. I have succesfully used combinations with tires one or two sizes smaller than reccomended (I figure it is ok as long as the rim is not wider than the tire), and I have successfully used tires four or five sizes wider than reccomended. Below the chart is the disclaimer
"Note: This chart may err a bit on the side of caution. Many cyclists exceed the recommended widths with no problem. "

Personally, I would not hesitate to use 32 or 35mm wide tires (CX standard widths) on a narrow road rim, but it is very unlikely in your case that anything wider than 28mm will fit in your frame or fork.

Gio7

Well I just looked at some tire clearance pictures of caad 8 and it looks like ur not going to much options but there is a way around that. First get a decent cross fork and put the biggest tires you can get on those which is probably gonna be 31c that have some nice grooves and caliper brake. Handling is very Important especially in cross where you go through stuff like sand. Now I'm not sure what material the caad 8 is but of its steel than you can take some long nuts (like they kind they use to tighten steel support wires on the street) you'll also need one of those huge u grip things they have at hardware stores. Now put the take the wheel and drive train off get one of those plastic shipping blocks that go on the dropouts and put it on then put the nut where you're lacking clearance, grip it with the huge u grip and tighten. It should depress those clearance giving you more clearance

pierce

pretty sure that C*dale is aluminum, most all of them have been since like the mid 80s. unless its carbon fiber. I would not even attempt to reshape aluminum OR carbon fiber frames.

edit: ahhh. CAAD8 is 6061 aluminum. yup, don't even think of trying to re-shape the stays or whatever. and a carbon fork, ditto.

Wilfred Laurier

hilariously bad advice. Thanks for the laugh!

FastJake

The rims aren't the limiting factor, the frame is.

You need a different bike. Running 25mm tires on any real cross course will be murder. Get a cross specific bike or a nice light hardtail/rigid MTB.

Wilfred Laurier

Road bikes cannot easily be converted to cyclocross bikes, but cyclocross bikes can be easily turned into quite capable road bikes.

Why not sell your mtb and your road bike and get a CX bike and a set of wheels for road riding?

pierce

bingo, best suggestion yet.

HillRider

About the closest I know of to a bike that will do double duty as a decent road and passable CX bike is the Surly Pacer. It has frame and fork clearance for 700-32 or slightly bigger tires and uses long reach (47-57 mm) caliper brakes so there is some mud and crud clearance there. I wouldn't try it is really thick, muddy races but for all but dreadful conditions it should work. It has road geometry and is a decent (but not light) all-around road bike.

Surly's Cross Check is closer to a dedicated CX bike with even more tire clearance and cantilever/V-brake mounts and a bit more "relaxed' geometry. It too will double as a usable road bike for general riding and even as a decent tourer since it has eyelets for both racks and fenders.

Both of these are welded steel frames and available at pretty reasonable cost so they aren't budget busters for most riders.