Help with building my cross bike - tire question
 

I am getting close to finishing building a cross bike for my wife. I bought a Planet X Kaffenback steel frame off ebay and am using a mix of new and used Shimano components to build it up. I knew there was not much clearance between the seat tube and rear wheel so I bought 700x30 tires for the bike (Michelin Jet) - but it still looks awfully close - see picture. Being a newbie to cyclocross, I assume this could be problematic, but I don't know for sure. My wife is mainly going to use this for rails to trails type riding, she doesn't see any racing in her future.

Any recommendations for different tires, or should I just see how these ones go?

looks a little close to me, but for general light riding it shouldnt be a problem. Racing, with mud and stuff building up there may be issues but for railtrails and fitness it should be fine. You might cinsider putting some kind of thin adhesive on the back of the seattube, thin clear plastic or something to help prevent damage to the frame....

~S

The Michelin Jet tires are labelled 30c but they are pretty big, more like 35c in reality. The PlanetX site says that model can use up to 32c tires- looks like youre at the limit with the Michelins. Which is too bad, and pretty stupid actually because clearly you can't fit a lot of common cross knobbies in there, which sucks if you really want to do any real cross riding or get into any mud. I'm no builder, but it looks like they need a design tweak- add another few mm's to the chainstays, or steepen the seat tube angle. Anyway, the clearance with the Jets is probably OK until you get into any mud- you'll want to protect the frame with something like electrical tape, or you can also use clear contact paper or something. The paint will wear off in that space pretty quickly. If she's really riding mostly on pavement, with a little dirt path riding, you might consider a 28c road tire- Continental gatorskin, Specialized Armadillo, Panaracer Pasella are three that come to mind, and there are others. A 28c tire pumped up to 90 psi will be fine for dirt paths, and faster than the Michelin Jets on pavement. What the heck were they thinking at Planet X???

Boy this is really close. But it's hard to tell what the real problem is only from the picture. Are you sure the frame takes 700mm rims? Perhaps the frame is very small, but Iwould doubt that the frame maker would make such a flaw and leave so little room. It might sound cheap advice, but take it to a good bike shop and have them look at it. perhaps they can come up with some ideas. F

Michelin sizes their tires honestly. Their 28's are larger than most 32's. Try it out, and if it rubs, then use a smaller tire. My ritchey 32c's are way smaller than what you have on there.

I actually swapped in my 32c Bontrager Jones CX tires from my Poprad and was pretty surprised to see I had significantly more clearance than with the Michelin 30c's. I guess the sizes can be taken with a pinch of salt. I guess we'll swap tires for the moment and see how the Bontragers work - otherwise I think 28c road tires will be fine since my wife has no interest in racing at this stage.

Looks a bit tight... If you're interested I've got a frame mint Cannondale T700 for sale that would fit you nicely. I just posted it earlier. http://homepage.mac.com/tonyreidsma/...oAlbum164.html

Tony