How to change your gearing without changing your gears!

Discussion in 'General Questions' started by Large Filipino, Aug 12, 2008.

  1. TIRES!
    My back tire finally worn down to the point that my slime tube couldn't do it's thing no more. Photo0411.jpg In the middle it's pretty weak. 2250 miles not too bad.(front tire is like new though. Go figure.) So off to Wally world for a new slime tube and a tire but those tires they have in a box SAYS "will work for 26.2.125" but in reality these are 26.175 tires. So I declined and bought my tube and went home.
    I grabbed an old tire and put it on there. That center stand rules because place my tool bag up front and my rear wheel rises. No more Ghetto Stand!
    I should have taken a pic without my rear wheel on the bike. It rules. I almost WANT to have a flat in front of many people so they can say "Cool" when I do a tire change.
    Well anyway,here's my tire now.
    Photo0412.jpg Photo0413.jpg
    A 26.175 which is the tire pictured is about a HALF AN INCH shorter or even more than a 26.2.125 tire! Took it for a ride and it pulls harder. Yes. You can tell.
    These tires don't get discounted too much at the bike shops but that cool one where I got my rim cheap tells me I can get a decent balloon tire black-wall with a 20 dollar bill.
    I gotta wait a couple of weeks. For now this is okay.
    So. You wanna go faster but you don't have a 40 tooth and are rolling in 26.175 tires? Get balloon tires.
    That's my tip of the day.
     
    Last edited by a moderator: Aug 12, 2008

  2. ZnsaneRyder

    ZnsaneRyder Member

    Thanks for the helpful tips, and the good pic of your motor on the back.

    Also I have noticed tire-size really matters. My new trailer tires are about a 1/2 inch smaller in diameter and the RPMs max out faster.

    Have you considered the no-flat foam tubes for the bike tires? Walmart sells them for $20 for a 26 inch tire.
     
    Last edited: Aug 12, 2008
  3. Been there done that. It's okay IF you get them on PERFECT with a PERFECTLY STRAIGHT rim. If you are off by even a little in back you will be rewarded with a never-ending "thump thump thump" as you are riding along.
    It's very easy to get a high spot when you get that last inch over. Now i have a solid tube on my front tire on my original MOOP and that's still true as an arrow and rolls smooth.
    I like my slime tubes for it's very forgiving. I don't put too much air in them though for I had one explode on me. 35 psi TOPS. I like 32. But others have put more air in.
     
  4. SirJakesus

    SirJakesus Guest

    I find changing sprockets less annoying than changing tires. However I'd had the same plastic tire levers from when I was in the 7th grade and rode the furthest in our schools "bike-a-thon" and it was my prize or something for raising a lot of cash for our field trips. I went something like 34 miles in 2 hours ( I think.) So they were worn out and would keep slipping off the tire bead constantly on my last tire change when I replaced my spokes. Fearing the thought of having to deal with that again I bought some nasty 9in long forged steel tire levers from performance bike :)
    It makes sense though large, just remember to adjust your cyclocomputer to the new diameter or you'll be getting inaccurate readings and your mileage will be way off with time. Only if you change both tires of course. The rear only shouldn't change anything with your readings.
     
    Last edited by a moderator: Aug 12, 2008
  5. It seems the wally world tubes don't fly too well with the tire I bought at the bike shop. It's sized 26.2.200 something huge like that. The gunk leaked from close to the valve stem. Apparently when inflated that area doesn't expand as well as the rest of the tube and then you get a air pocket. Then when you get a small hole the gunk won't work.
    So some pics from today. I found that rock on the side of the trail. That insures it will keep the back end up. That's my tool pouch.
    I've had an unusually large amounts of compliments today. Way more than usual. And from roadies yet.
    I guess every day can be different. The replacement tube did the same thing so I stopped at the bike shop on Speer BLVD and got the right sized tube. It's not a gunk tube but it works rather well. Far better than with my other tubes.
    Those universal sized tubes are okay when you got a rather small tire,but when you get to the balloon sized tires,wally world can't help you with tubes. They make them too small.
    I didn't take pics at the bike shop but I didn't find any large rocks to weigh down my bag for my ghetto stand effect so I filled my bag with the decorative rocks by the sidewalk. Then I returned them when I was done.
    Oh one little trick when changing a tire on the side of the trail. Removal is easy because your tire is already deflated but when installing don't pump up that tire until it's installed. That way you don't have to fiddle with your brake pads. And pump up a new tube a little before installing. That gets rid of folds that may cause you a leak down the road.
    Notice the lack of tire levers. I don't use it. I use only my hands.
    Superman. :grin:
     

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    Last edited by a moderator: Sep 10, 2008
  6. terrence

    terrence Member

    Great pics superman lol. Its back to the drawing board often with these MB's. The titan mount looks fairly simple for tire swaping. Roadside tire changes are always interesting.
    Looks like your a pro at it.
     
  7. sparky

    sparky Active Member

    Large, you need to quit changing your tubes so much, man!! Find some tube liners for both sides of the tubes at your local bike shop, or order them online for the next time this happens. Also, forget the slime tubes and pick up some heavy-duty tubes. At your bike shop, they'll have heavy-duty and thorn-resistant boxes with a representation of how thick the tube is all around, so you can choose which one you like best.

    I'm using a regular tube on the front & a thorn-resistant tube on the back... no flats since I've put the tube liners on, so even heavy-duty tubes could be a "waste" of money, but I doubt it since this should be the last time you ever change a tube on your bike. And I've ridden over every sharp object I could find just to try to pop the tubes. If you do manage to pop one, the tire-side tube liner (at least the one I found) will send you a brand new tube and tire liner after you send them the punctured tube and tire liner. Totally worth it!!
     
  8. SimpleSimon

    SimpleSimon Active Member

    You know, Large, you get me thinking qiuite frequently. This thread, and the various posts about optimizing roller diameter for hill-climbing torque, vs flat road cruising with a rack-mounted friction drive prompted me to draw up this sketch.

    Basically, you make a roller U channel long enough to put two rollers in of differing diameters, then mount that on a center pivot with bushings to an upper plate with offset "earflaps" down to your pivot axle. Put a drive gear on each axle end for the rollers, outside the U channel and a third gear on the upward projecting jackshaft mount, all co-planar (as represented by the red shading in the sketch.

    Put a compression spring (blue cylinder in the sketch) between the end of the U channel and the engine mounting plate, with a manual choke cable running forward where you can pull it out (compressing the spring) and lifting one roller off the tire whilst pressing the other roller onto it.

    Voila, two different "gear ratios" out of one mount. Heck, do it right, you could go with three different ratios/rollers, although that gets just a smidgeon more complicated to fab up.
     

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  9. sparky

    sparky Active Member

    Are you related to Simple Simon, SimpleSimon??

    I'm soo curious about the Mitsubishi ENCORE system from Dimension Edge. How in the world does it "shift on the fly"?!?!? I like that Simple Simon video, and the whole shifting on the fly with a friction drive kit definitely seems like what I want on my next bike if it's legit.
     
  10. SimpleSimon

    SimpleSimon Active Member

    That's not mine, sorry to say. I wasn't even aware of it. Didn't watch the video - my eyes are pretty bad, and most videos are useless to me. After reading over the description and looking at the pics, it does look similar to what I envisaged, except it looks like the "shift on the fly" system is basically a lever engager for the drive roller. What I've sketched up is basically a two-speed variable roller system. Could readily be three speed, but as I said, that gets a bit more complex.
     
  11. Happy Valley

    Happy Valley Active Member

  12. sparky

    sparky Active Member

    It's not that long, but it definitely shows how quiet friction drives are... or at least how loud my chain drive is.

    Yea, I figured that's what it had to be. I could tell by looking at all the marketing speak that something wasn't right, but I do get sucked into pretty adverts like that sometimes.

    Yea, I still don't understand how it changes rollers, but if it'd be cheap... I want the first one you ship out! K? ;^)
     
  13. sparky

    sparky Active Member

    I missed that one. I just found it funny that SimpleSimon came up with this shifter system for rollers, and I remembered the Dimension Edge system said something about shifting... was a bit odd to me.

    Anyway, doesn't sound like Dimension Edge could be any better than Staton after all. But it seems like that guy just didn't install it properly... just doesn't understand physics or something.

    Luckily, my folding bike came with the motor attached and shipped to my front door for just $500 with excellent support. The bike's not the greatest quality, but it's definitely worth the money.
     
  14. SimpleSimon

    SimpleSimon Active Member

    Unfortunately, sparky, I don't have a shop or tools to fabricate the idea. I tossed it out there for anyone who might be interested.

    If you look at the sketch I posted, the blue transparent cylinder between the two green plates represents a compression spring, with the vertical line through the center representing a cable. Pulling the cable raises the end of the lower plate in relationship to the upper (which is the fixed frame plate with the engine mounted to it), causing it to pivot around the central small shaft. That raises the smaller front roller off the tire tread, and presses the larger rear roller to the tire. Just simple geometry.
     
  15. SS that's Genius!

    I say keep it all spinning all in line just like in your sketch then have the entire thing including engine slide on roller bearings or something similar to rollers you find in file cabinets or good tool boxes. Then connect it all to a shifter up front with a solid bar connecting it all. Middle is neutral.(both rollers aren't touching the wheel) Forward is first gear or climbing gear. Back is second gear or cruising gear. All done on the fly! And when on cruising gear the engine is further back,more room to stretch.
    That idea most definitely has merit. BRAVO!@!
     
    Last edited by a moderator: Sep 12, 2008
  16. sparky

    sparky Active Member

    It's too beautiful, man!! ... now that I understand how it pivots. It's simply amazing!
     
  17. SimpleSimon

    SimpleSimon Active Member

    I like that, Large, I like that a lot. Unfortunately, I see some fab issues in making a rack/shift linkage work smoothly - the geometry varies a great deal from bike to bike - you'd just about have to fab up a custom linkage for each installation. Now, take your same idea, and instead of rod linkages go with a long throw cable mounted on a positive throw/snap lock lever arm shifter (like the old Stingray three speeds had), and you got something. I can even see a powered reverse from a friction drive along with two (or three) speeds.
     
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