Rollers vibrating, "pulsing" sensation - is this normal?
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  1. #1
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    Rollers vibrating, "pulsing" sensation - is this normal?

    I bought a set of very old Kreitlers from someone in the local cycling group. They were "garaged" for about a decade-plus. They are plastic rollers, which I can't even find mention of online. Appear to spin without a lot of resistance by hand. Bought a replacement belt and set them up.

    There is a very clear pulsing vibration from one of the rear rollers which shows up every single time I downshift into a harder gear, and when I'm anywhere above ~180 watts it's there all of the time. It's feels like the rear wheel is bouncing up and down off of the roller. The vibrations really start to get ridiculous.

    I tried running lower psi in my tires, thought it might be a road tire issue so swapped to a rear trainer tire to see if that would help, nothing seems to make it go away. Is this kind of pulsing "normal" for rollers, or do I need to drag these back to the person I bought them from and ask for my money back?

  2. #2
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    Quote Originally Posted by Mad Cow Disease View Post
    I bought a set of very old Kreitlers from someone in the local cycling group. They were "garaged" for about a decade-plus. They are plastic rollers, which I can't even find mention of online. Appear to spin without a lot of resistance by hand. Bought a replacement belt and set them up.

    There is a very clear pulsing vibration from one of the rear rollers which shows up every single time I downshift into a harder gear, and when I'm anywhere above ~180 watts it's there all of the time. It's feels like the rear wheel is bouncing up and down off of the roller. The vibrations really start to get ridiculous.

    I tried running lower psi in my tires, thought it might be a road tire issue so swapped to a rear trainer tire to see if that would help, nothing seems to make it go away. Is this kind of pulsing "normal" for rollers, or do I need to drag these back to the person I bought them from and ask for my money back?
    check your wheel since you alreaady ruled the tire out. I had a similar issue, turns out a patched tube was the culprit. The rollers are machined to a BIT higher specs than the road! If you want to check the roller for "round" it would be easy with a dial indicator.
    Of course I'm sure...that doesn't mean I'm right.....

    "There's no sense being stupid unless you show it."

  3. #3
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    I have had Kreitlers for over 30 years and I have never known them to make a "plastic" roller. Challenger models, yes have nylon end caps, but the drums for all Kreitlers have always been lathe turned aluminum.

    Are you sure yours are really Kreitlers?

  4. #4
    'brifter' is f'ing stupid
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    I agree...every Kreitler I've ever seen and owned had aluminum rollers. The less expensive ones have plastic end caps, the better ones have aluminum end caps.
    #promechaniclife

  5. #5
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    Quote Originally Posted by GKSki View Post
    I have had Kreitlers for over 30 years and I have never known them to make a "plastic" roller. Challenger models, yes have nylon end caps, but the drums for all Kreitlers have always been lathe turned aluminum.

    Are you sure yours are really Kreitlers?
    Yup, it's got the Kreitler caps on the end. Some older versions of this type pop up on eBay occasionally. They are quite uncommon, as far as I can tell. Here's a photo of what they look like -- not mine, but very clearly plastic.

    Vintage Al Kreitler Custom Rollers & Killer Headwind (No Belt) - Bike Recyclery

  6. #6
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    Quote Originally Posted by Touch0Gray View Post
    check your wheel since you alreaady ruled the tire out. I had a similar issue, turns out a patched tube was the culprit. The rollers are machined to a BIT higher specs than the road! If you want to check the roller for "round" it would be easy with a dial indicator.
    These aren't machined. They are molded plastic. That's not a tool I have, and there do appear to be some imperfections because I can see them oscillating slightly when I spin. I don't think

    I really don't think a tube is the issue here. Running the tire at 100 psi on the first try would mean there's barely any yield when I press on the rubber. Does this "thumping" mean that the roller is uneven? Because I don't get this kind of vibration on a trainer with a metal resistance unit, using the same wheel.

  7. #7
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    Yeah, Kreitler made plastic rollers at one point. I had plastic rollers of another brand at one time. The plastic can warp if left in a hot place, and they can crack.

    You've got a bad roller. Try to find a replacement, or you might be able to purchase one direct from Kreitler. I've also seen just the rollers for sale on eBay, but you'll likely have to buy a complete set.

  8. #8
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    Kreitler did offer a low cost plastic roller option many moons ago. You might try swapping the unbalanced or un-round roller form the back wheel to the front wheel to see if that makes any improvement. You have little to lose at this point. It might also be worth checking to see if you could swap in current Al rollers in place of one or more of the plastic rollers - it might not make much financial sense. But others have said, make sure you rule out your wheels, as even at 100PSI, it doesn't take much of an imperfection to start an oscillation.

  9. #9
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    Quote Originally Posted by Mad Cow Disease View Post
    These aren't machined. They are molded plastic. That's not a tool I have, and there do appear to be some imperfections because I can see them oscillating slightly when I spin. I don't think

    I really don't think a tube is the issue here. Running the tire at 100 psi on the first try would mean there's barely any yield when I press on the rubber. Does this "thumping" mean that the roller is uneven? Because I don't get this kind of vibration on a trainer with a metal resistance unit, using the same wheel.
    hey, think about this.....you have a spinning cylinder, with bearings truing it up should be a no brainer. It's essentially a lathe.

    I bet any decent machine shop would do it for you. My rollers are a cheap set of "performance bikes" bought as returns and I think I paid 75 bucks for them. During the winter I use them every day
    Of course I'm sure...that doesn't mean I'm right.....

    "There's no sense being stupid unless you show it."

  10. #10
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    Have you checked to see if there might be a bent axle? I wouldn't think that it's a bearing, but it may be and if it is they're easy and cheap enough to replace. I've got an old set of plastic Kreitlers and one of the drums was submerged at some point and the bearings were shot, I was easily able to replace them. The bearings I needed were 1614zz.

    You should also be able to clamp a steel straight edge to the frame rails parallel to each drum and check for runout. Just have someone support the bike and crank the pedals by hand while you check for runout. Can use a pencil or sharpie of sum-such to indicate the high points.
    Too old to ride plastic

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