650 wheels on a cross bike?

[Kathi]

Yikes, have to leave this wonderful state and SG? How awful!

[MartianDestiny]

Yikes, have to leave this wonderful state and SG? How awful!

I know!!! I've got 3 years to figure it out though. (maybe Chris will give me a job, LOL)

[Kathi]

Maybe he'll expand like Divas did and open a shop in Denver. You could be his manager.

[whsh93a]

OK - I'm a guy whose wife uses a 650c bike and wanted some decent tires for doing a bit of cx and winter commuting. You all have found out that no one makes them. So...I converted some 700c to 650c. It's not hard but takes some patience.

Here's how to do it. Not sure if this will take multiple posts or not.

Find some not too knobby cross tires like Specialized Speedmax. Too lumpy and the tire won't clear the brake stays.

Tools and stuff needed are scissors, Dremel type rotary tool (get one at Harbor Freight sometimes for free). Hot glue and gun, Metric box nut with tangs for #3 metric stainless steel screw. Barge (or equal) rubber cement. Some fabric - I used some from a nylon grocery bag. Phillips screw driver. Model saw or maybe Xacto blade. I like the model saw because I won't likely cut myself with it. A power drill and a 7/64 drill bit. See photos 1 - 4.

So - pick a tire and cut it in half. Use the Dremel to cut the wire bead - both sides - and use the scissors for the rest. See photo 5 - 7.

Take a 650c rim and slide the cut tire onto it. Overlap the tire ends and slide them together ALL the way so that the bead is inside the rim. Mark the point where the inner tire end entered into the outer end. Photos 8 and 9.

Remove the tire and cut the inner tire's bead again at that point (both sides, of course) with the Dremel. Trim off the bead with the scissors. Photos 10 - 12

Cut off all but around two inches of the soon to be denuded bumps tire section. Trim the bumps off the inside tube (the section without the bead now) using the model saw or Xacto or whatever you want. You only need to trim the bumps from a couple of inches. You could get away without trimming anything but it makes for a better fit. Then, if you are a bit of a perfectionist, flatten out the remaining bits with the Dremel. Photos 13 - 17

See next post for part two

[whsh93a]

Cut off all but around two inches of the soon to be denuded bumps tire section. Trim the bumps off the inside tube (the section without the bead now) using the model saw or Xacto or whatever you want. You only need to trim the bumps from a couple of inches. You could get away without trimming anything but it makes for a better fit. Then, if you are a bit of a perfectionist, flatten out the remaining bits with the Dremel. Photos 13 - 17

Fit the two ends together so that the two sets of cut bead ends touch. Then, glue the two ends together using hot glue. Hot glue is great because it can be remelted if you make a mistake and stays flexible. I just put hot glue on the denuded tread and then reheated it with the heat gun before fitting the tire sections together again. Photos 18 - 22

Put a 650c tube into the incomplete tire and fit it onto a 650c rim. It's not very neat looking, yet. Make sure the bead is inside the hooked rim and inflate the tire with about 10 lbs. pressure. If it's too loose, then take it off, reheat it and slide the two sections together more tightly. You may need to cut some bead off if you made it too loose to start. Photos 23 - 24

It fits OK. Deflate it, remove the tire and tube. reinforce the seams using cut pieces of nylon cloth (or cotton or whatever) glued into the inside of the tire with the Barge cement. Cover the seems at the butt ends of the two beads and the end of the tire overlaps. Photos 25 - 26

Let the glue dry for an hour or so. Use the spare time to try and remove all the glue from your fingers. Good luck with that. Then, remount the tire onto the rim and verify it fits. Inflate the tire again to maybe 15 lbs. The expanding tube will help set the glue. Let it sit for maybe 10 minutes like that.

Take off the tire, remove the tube and drill a single hole through both sections of tire using the 7/64" bit. Try not to drill your hand. Choose a point maybe 1 inch back from the cut end of the top section and in between the bigger knobs. Photos 27 - 28

See Part three.

[whsh93a]

Now, the trickiest part. Take the short #3 metric screw and screw it into the hole. The screw should be just long enough that the end begins peaking out of the inside of the tire. Then, line up the box nut with the screw end and tighten the screw. You may need to do the lining up by touch - you should be able to feel when the box nuts end is on the top of the screw end. Tighten down the screw. As you do that, the sharp tangs will embed into the tire. This makes a really sturdy seam that won't separate. I then added a drop of Barge to the end of the screw to make sure it will never loosen up. Photos 29 - 30

I added a strip of Mr. Tuffy to the inside of the entire tire but you don't need to do that. Insert tube, mount it onto the rim making sure the bead is seated correctly and inflate to 60 lbs. make another tire and then put them onto the bike.

My wife has used these for commuting and cx and they work great. The only little irritation is that the tires make a sound every time the seam passes over the ground. Any bump is minimal. See the rest of the photos.

Hopefully I numbered the photos correctly and didn't miss anything.

Good luck. It really works.[/B]

[whsh93a]

Looks like you skipped Part 3.

Interesting project, though. I'd want to hear how well the tire holds up. I think someone could take this idea to a competent builder if they were interested.

=========================
I posted part three three times and each time I received a message that it needed to be approved by the webmaster or something. I think I saved it. I'll try again.

Here's a photo of my wife just yesterday using the tires.

[whsh93a]

Let's try it again...

Now, the trickiest part. Take the short #3 metric screw and screw it into the hole. The screw should be just long enough that the end begins peaking out of the inside of the tire. Then, line up the box nut with the screw end and tighten the screw. You may need to do the lining up by touch - you should be able to feel when the box nuts end is on the top of the screw end. Tighten down the screw. As you do that, the sharp tangs will embed into the tire. This makes a really sturdy seam that won't separate. I then added a drop of Barge to the end of the screw to make sure it will never loosen up. Photos 29 - 30

I added a strip of Mr. Tuffy to the inside of the entire tire but you don't need to do that. Insert tube, mount it onto the rim making sure the bead is seated correctly and inflate to 60 lbs. make another tire and then put them onto the bike.

My wife has used these for commuting and cx and they work great. The only little irritation is that the tires make a sound every time the seam passes over the ground. Any bump is minimal. See the rest of the photos.

Hopefully I numbered the photos correctly and didn't miss anything.

Good luck. It really works.

PS - Make sure the tire fits very tightly onto the rim. CX uses pretty low pressure. When commuting, tire pressure is higher and the bead grabs the rim more solidly.