Road versus CX frame?

stueys

Been faffing around trying to decide to get a CX bike to double up as my wet bike and also a trail option to ride with the kids. Sold on the CX bike idea and about to pull the trigger on a Planet X uncle John frame/fork which I'll build up with a nice 105 compact group set.

Two quick questions;
1) anyone got any experience of the uncle John frame?
2) is there much differce between a road frame and a CX one? If I was just to buy a road frame with decent clearance for off road tyres what would I lose? I ask because the CX frames all seem slightly heavier.

Cheers

sungod

in general cx will be tougher hence heavier, geometry is a bit different to road, often a bit longer wheel base and higher ground clearance, cable stops on the top, room for wider tyres, either canti or disc brake mounts (usually with wider rear hub spacing), go for discs if you can, mechanical like avid bb7 road are fine, even bb5 are ok but a bit fiddlier to set up

danmitch

Hi - sounds really sensible to me. I had a Surly Cross Check for a very similar purpose, worked brilliantly as an all round bike for on-road commuting, trails and towpaths and more muddy off-road stuff. I used everything from 28mm road tyres, to 42mm cyclocross specific tyres, though the best performance was in fact from the brilliant Vittoria Hyper Randonneur (now called Voyager Hyper) in 37mm - truly outstanding tyres.

Most CX frames will have slightly higher bottom brackets and are often a bit heavier than regular road bikes, but the real world difference is small, the benefits are obviously the increased versatility. (A true competition CX frame may be lacking a lot of the braze ons you would need.) You will not find a regular road frame with clearance for anything more than 28mm tyres really, CX frames like the Uncle John or Surly Cross Check will give you comfortably 40mm plus mudguards.

As to the build, 105 compact is sensible, think about the Ultegra 12-30 cassette though as this will give you almost as much range as a triple (I wrote a blog article on this a few days ago here http://danmitch.typepad.com/a_bike_buil ... sette.html )

Hope this helps - Dan

cougie

Love my UJ cross frame. As fast as a road bike and can handle the rough stuff. I just have two sets of wheels. Lightweight for road and heavier duty for off road.
It's been up and down the alps all week and hasn't missed a beat.

stueys

Great thanks all, that me honing in on the UJ then.

I'm staying clear of disc brakes as I think that would prohibit me from running my normal road wheels. Am I correct?

sungod

yes, you'd need disc-specific wheels, so stick with rim brakes to use standard road wheels

the rear spacing may be 135mm, 5mm wider than road wheel rear hub

if it is wider, there are various approaches you can take, maybe one of the uj owners can confirm the spacing?

cooper.michael1

I've got an Uncle John, it's a really good bike and very adaptable. On the road with road tyres it's very lively, if you put some touring/CX tyres on it is behaves well off road too.

For a general all round bike you can't go wrong. Mine is built with Veloce and Open Pro's, and it certainly not heavy.

I ended up selling my Italian road bike shortly after buying the Uncle John just because I liked riding it more. I don't know why more people don't go for these type of bikes.

stueys

Thanks for that. Seems that the spacing is 135mm, which I guess makes sense if you want to run mtb type wheels. I'm assuming you can pinch the drop outs to take a 130mm wheel?

Also looking at the pictures, it appears that you need to run Canti brakes, can anyone confirm?

danmitch

Yes Canti or Mini-V (I prefer canti). Why not get 135mm wheels, it will give you a slightly stronger build and saves "cold setting" / bending the stays?

stueys

To be honest I've got a pair of krysrium elites and Aksium's that I wanted to run as road and trail duties respectively. I'm not going to do anything heavy off road , we're talking trails at best so 130mm should be more than ample.

Am I doing the stays harm from pinching to fit?

danmitch

Personally I wouldn't have a problem on a steel frame but I wouldn't be comfortable doing it with Aluminium.

stueys

danmitch wrote:

Personally I wouldn't have a problem on a steel frame but I wouldn't be comfortable doing it with Aluminium.

Ouch, so I'm looking at new hubs to use my existing wheels? Ay options like washers on QR etc?

cooper.michael1

I've only ever used 130mm road wheels with my Uncle John, and as a Mavic user this includes Aksiums. The rear stays just pinch together when you do up the quick release (they could be 132.5 for all I know). My Uncle John is a 2009 model, so unless they've changed the rear end spacing since then, I can't imagine you'll have a problem, i've seen other people with Uncle John's using factory road wheels too.

sungod

pinching the frame is common, if it were steel you could cold set it, but not advisable with aluminium, you may need to adjust the rear hanger alignment

an alternative, assuming the axles are long enough is fit a 2.5mm spacer (use washers) each side, that way you're not pinching the frame

either way, the chain line will be a bit out but not enough to matter, especially if you avoid cross chaining big-big

clazza

Uncle John's are great for light trail riding - very stable and predictable. I also have a 2009 model which I used with 130mm hubs so I think you should be fine

I'm getting rid of mine (M size) if you're interested - I got a Ritchey breakaway to replace it as I do quite a bit of travelling but to be honest the ride isnt as good at the UJ...doesnt feel as planted for some reason

Jim C

Don't cold set the Alu frame. And don't use 130 wheels if its a 135. I wouldn't use them if its 132.5 either - there's no knowing what that distortion is doing to the aluminium

Magic factory wheels can't easily be re spaced. Wheels with threaded axles are no problem- longer axle, a few mm of spacers, maybe a re dish of the wheel

The uncle John frame is ok, but it is heavy. It is disc mounts, which U don't want and these don't help the weight as its a bit beefed up.

Good cross frames are great as road bikes. BB is a little higher, but not noticeable on the road. I only have cross race frames (empella and van tuyl) which are a bit race specific- no bottle bosses, mudguard mounts, even tho there is plenty of room. If U look for a cannondale, giant tcx or crosslight, these would all be good choices. Ditto the surly crosscheck in steel or planet x kaffenback- but both are a bit heavier

stueys

Thanks all. I asked Planet X re the hubs and they've confirmed that in their view you can run 130mm without an issue or spacers required. I assume they are saying to cold set. I'll ponder, lots of good advice and experiences with the frame which helps.

ck101

I have a Genesis Equilibrium as my winter bike, they're great. Personally I'd stay away from CX type bikes if you plan on using it for club winter road training.

robbo2011

May I ask why?

Jim C

Plenty in our club use cross frames year round, for club runs, chain gang, work bikes. some race on them, especially the youths. With and without mudguards. I can't think of any reason not to - they're great all founders. Its probably only marketing by the big companies that they're not more popular. Id highly recommend a good cross bike as a do it all bike- even quite serious MTB type use when U have the confidence

cougie

If i had to choose just one bike to keep from my fleet it would be the UJ. Its fast on road and can do off road and can take full guards. If you looked at the British Olympic bikes last year - they had big clearances on the forks - must be for aero benefits - and you get that on a cross bike too. ;-)
Mine has done 100mile sportifs, Ironman races, Adventure races, trips to the High Alps and plenty of domestic pootling.

FransJacques

Please search under "SuperX" within the forum - a couple of us advised jimm on a CX bike and in 6 pages we did a decent job of killing the pros and cons. If you have follow up questions, post them and we'll gladly fill in our personal experiences.