MTB to 'Cross Conversion Questions

[smailsteve]

Have decided to morph my Bridgestone MB-2 into a 'cross racer (except the 700c wheels, which I don't think I can do on this particular frame, or want to bother with, at least). Plan on non-serious racing with it.

Anyway, I've got most things figured out, but need a few suggestions/hints

1. GEOMETRY Since this is a MTB geometry, should I start out by selecting parts/sizes to mimic my road bike feel (52cm Trek 5200), or should I be more upright, more stretched out??? I'll be using road bars with Shimano STI shifters (see #3 below for stem choice)
2. TIRES Since I'll be using standard 26" MTB wheels, what MTB tires should I consider (prefer Ritchey/Michelin/Continental, but anything considered). Having a hard time finding something that has an acceptable tread pattern but not a beefy/heavy MTB tire. Like to find something in the 1.25-1.5 inch range.
3. STEM Thinking about getting the Ritchey Pro Adjustable Stem (80mm extension) so I can tweak the fit at least a little bit once it is built. I'm fine with the weight penalty, but any experience out there with this stem? Literature says it will fit a 25.4mm road bar, which I have to assume means your standard 26mm road bar, since I can't find any 25.4 road bars out there). I'll also be using a threadless/threaded stem adapter so I can use the original 1" threaded Ritchey Fork.
4. BAR WIDTH My road bike bar width is 40cm. Should I stick with the same width or go to a 42cm for more leverage?
5. For those of you with the top-mounted in-line brake levers, do you really use them? Both of them? Really?

For those about to 'Cross, I salute you.

Thanks,
Steve

[jeremyb]

1. I wouldnt go more stretched than your road bike, actually i like a little shorter cockpit on my CX bike because i feel like i have more control in the singletrack/sketchy stuff.

2.tires can be found at www.cyclocrossworld.com http://www.store.yahoo.com/cyclocrossworld/hutcroscom26.html
thats the hutchinson cross comp 26x1.3. it largely depends on what kidn of terrain youre going to be on, might want something a little more aggressive for thick mud.

3. yeah that ritchey will fit a 25.4 bar (a mountain bar) oval makes an adjustable stem that look just like the ritchey but it is for 26.0 road bars

4. thats a personal choice, i like the same width, others feel a wider bar gives them more control.

5. another personal call, ive never had them, but felt i would have used them at a couple of races last yr if i had them, if you get them, yes install both, control of both brakes is a good thing.

take care
jb

[Milice]

you may be able to stick 700c wheels on that frame. You will need to pick up a se t of adjustagle height brakes. I just buit up a single speed cross bike on a gaint Iguana frame.

Keith

[cyclintom]

The MB-2 is a good project. You'll need a stem and drop bars. Bar End shifters and 9 speed wheels. I think Hutchison is making some 1.3" x 26" tires. Ultegra brake levers like Rivendell is presently selling are PERFECT.

I would think seriously about putting a carbon fiber fork on the MB but weight isn't the reason - it's to get rid of that nasty front end tank slapper that they are known for. I stopped them on mine by putting huge honking tires on it so that the weight of the tires would dampen out the oscillations. The initial flex of the carbon forks would probably do the same thing without adding 2 lbs.

I've finally settled on a Pinarello that is the same size and general dimensions as my old MB-2. People say, "Isn't that too small for you" and then when we're on the side of a hill and they can't touch the ground and I'm standing there easily they start to get the idea.

The real challenge is getting the weight of an MB-2 down to something under 28 lbs with everything mounted.

[spunkyruss]

Ritchey makes both a road and an MTB version of their adjustable stem.

[spunkyruss]

....you may be able to stick 700c wheels on that frame. You will need to pick up a se t of adjustagle height brakes.....

Do you have any suggestions for adjustable height brakes? I just did a bit of searching, and the only things that I came up with are http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7224760606&ssPageName=MERCOSI_VI_ROSI_PR4_PCN_BIX_Stores]these ( [url) Tektros on ebay,[/URL] but I don't even know what model they are.

[jeremyb]

your link didnt work for me.

you only need adjustable height brakes if you want to run 700c wheels.

i think one of the coolest mtb CX bikes ive ever seen is this one.



http://forums.roadbikereview.com/showthread.php?p=364346&page=3

He used disc brakes.

something like these onza HO's might work for 700c wheels (if if if you have enough clearance) otherwise if suggest just go with the 26" wheels.
http://i18.ebayimg.com/01/i/04/d4/d9/a7_1_b.JPG
http://cgi.ebay.com/onZa-HO-cantilever-brakes-Cyclocross-NOS_W0QQitemZ7227128596QQcategoryZ27949QQrdZ1QQcmdZViewItem

[same time]

I did a similar project with my MB-6.

for the stem, I highly recommend one of these:

http://www.rivbike.com/webalog/handlebars_stems_tape/16007.html

It puts the handlebars up where they need to be. A regular stem will usually put road handlebars way too low on an older mtb. Make sure the handlebar clamp diameter matches your handlebars.

Your MB-2 will make a cool off-road cyclocross bike when you're done, but it will be pretty heavy compared to, say, a Redline Conquest or something. Forget shouldering it, if you have a runup just push the thing.

Good luck, and have fun!

[spunkyruss]

your link didnt work for me.....

Sorry about the dead link. This (http://cgi.ebay.com/New-Tektro-CNC-Cantilever-Brakes-2-Pairs_W0QQitemZ7227275777QQcategoryZ27949QQssPageNameZWDVWQQrdZ1QQcmdZViewItem#ebayphotohosting) is what I was trying to do.

Those Onza brakes look great. Thanks for the suggestion.

[Milice]

yes the Onza's are the ones I am using. They show up on ebay all the time. There out of Mexico if I remember right, Are you going to gear the bike or go single speed?

[smailsteve]

jeremyb
great suggestions and thoughts. I totally overlooked the 26 tires on cyclocrossworld.com. I think your oval adjustable stem is the same one (at least the MTB version) that Nashbar rebrands. Unique metal disc on the side gives it away.
thanks, steve

[smailsteve]

Keith...you know, I just went into the basement and stuck my road wheels on the MB-2. I don't know why I didn't try that before. If I could find some of the alternative canti brakes that some other posters have mentioned, that would be a great stage 2 morph for this bike. What adj height brakes did you end up using on your Iguana? Thanks, Steve

[jim-bob]

If for some reason you feel like spending a ton of money, check out http://www.paulcomp.com/motobmx.html

[smailsteve]

Ritchey makes both a road and an MTB version of their adjustable stem.

I know, but I can't find anyone selling them and ritcheylogic.com is one screwed up website to find anything. Their PDF catalog looks like it's just the MTB version, at least at that point. I'll keep researching it, though...I've seen them on road bikes in the local shops...thanks. steve.

[smailsteve]

I did a similar project with my MB-6.

for the stem, I highly recommend one of these:

http://www.rivbike.com/webalog/handlebars_stems_tape/16007.html



Nice stuff there and thanks for that lead, too. Any chance you could post a pic of the MB-6 so I know approximately what the end product will look like? thanks steve

[cyclintom]

I recommend against the Paul levers or anything like them. V-brakes are so close to the rim that they immediately jam up with mud. That's why everyone is using regular cantilever brakes in the first place.

I also don't see a lot of point in using 700c wheels when you can get the Hutchison CX tires off of Cyclocross World.

If you're planning on making massive changes to the bike why not put in another couple of hundred bucks and get a CX frame and fork as well?

[same time]

Any chance you could post a pic of the MB-6 so I know approximately what the end product will look like? thanks steve

Ahh, too late. I already took it apart and put the flat bars back on it, with a Softride suspension stem for an upcoming 24hr race. I tinker way too much with that bike...

[Ronsonic]

Have decided to morph my Bridgestone MB-2 into a 'cross racer (except the 700c wheels, which I don't think I can do on this particular frame, or want to bother with, at least). Plan on non-serious racing with it.

Anyway, I've got most things figured out, but need a few suggestions/hints

1. GEOMETRY Since this is a MTB geometry, should I start out by selecting parts/sizes to mimic my road bike feel (52cm Trek 5200), or should I be more upright, more stretched out??? I'll be using road bars with Shimano STI shifters (see #3 below for stem choice)
2. TIRES Since I'll be using standard 26" MTB wheels, what MTB tires should I consider (prefer Ritchey/Michelin/Continental, but anything considered). Having a hard time finding something that has an acceptable tread pattern but not a beefy/heavy MTB tire. Like to find something in the 1.25-1.5 inch range.
3. STEM Thinking about getting the Ritchey Pro Adjustable Stem (80mm extension) so I can tweak the fit at least a little bit once it is built. I'm fine with the weight penalty, but any experience out there with this stem? Literature says it will fit a 25.4mm road bar, which I have to assume means your standard 26mm road bar, since I can't find any 25.4 road bars out there). I'll also be using a threadless/threaded stem adapter so I can use the original 1" threaded Ritchey Fork.
4. BAR WIDTH My road bike bar width is 40cm. Should I stick with the same width or go to a 42cm for more leverage?
5. For those of you with the top-mounted in-line brake levers, do you really use them? Both of them? Really?

For those about to 'Cross, I salute you.

Thanks,
Steve

I almost did this with may 80s Fisher HKEK, but scored a great deal on a real cross frame and parts so went with that instead. Those old rigid MTBs should be great like this.

Cross geometry is a little different than road - more like a vintage road bike, so I wouldn't try to emulate it too closely. You'll probably want a higher bar, just a little closer for agility and much more time out of the saddle. Aerodynamics don't mean much in the cross world.

I like a little wider than road bars and with less drop. If you get to use the drops on a cross course you'll be sucking serious wind so the more open body position should help.

Personally I've got no use for the top levers. Never even thought about needing them so can't help with that.

Ron

[greybeard87]

Conti makes a "Cross Country Pro" in 26X1.5 that has an open tread but knida knobby for me.
I found some Hutchison "Cross Comp" in 26X1.3 , it has a nice open, small knobby patten that shed mud nicely and handle great. I believe I found them at Web Cyclery.