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  1. #451
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    Quote Originally Posted by slick50 View Post
    Just had a set of these rims laced to a pair of DT Swiss hubs and I am finding that the rear wheel groans under load. The rims flex and the spokes rub and squeak. Noise is only noticeable when under load and cranking uphill. The rims are pretty flimsy compared to a normal MTB rim which appears to be contributing to the problem. Curious if others have run into this.
    I truly can't believe the rims are flexing, what are you running for psi and what do you weigh? Does it seem like there is decent spoke tension?

  2. #452
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    Quote Originally Posted by slick50 View Post
    Just had a set of these rims laced to a pair of DT Swiss hubs and I am finding that the rear wheel groans under load. The rims flex and the spokes rub and squeak. Noise is only noticeable when under load and cranking uphill. The rims are pretty flimsy compared to a normal MTB rim which appears to be contributing to the problem. Curious if others have run into this.
    No way. I built my LB90 rims and they were a pleasure to build, because they made aluminum rims seem like a noodle in comparison. Usually, you have to go around an aluminum rim for a while and get the hop and lateral deviations out, but with the carbon rims, totally different. You can get them so insanely true because they are so much stiffer and a small difference in tension doesn't throw the whole thing into a crazy "chasing the true" operation.

    Something else is up. I built with revolution spokes (definitely not the stiffest) due to the wide spacing of the 90mm rim spoke holes and saving weight. They've been great and I have no more than about half an inch of clearance for my Dillinger 5 tires. They are close, but it doesn't rub and the rim is always super true.

    Couple of possibilities:

    -Spoke tension is weak (most likely).
    -Hub/flange is excessively flexy. This does exist, although it's more rare.
    -dropout flex (shimano-type skewer?)
    -frame flex (some aluminum chainstay yokes are particularly flexy)
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  3. #453
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    Thanks for the replies. Frame is a Surly ICT with 12 thru axel. Hubs are Dt Swiss. Problem is at the wheel. Noise comes regardless of tire pressure, issue is at the spokes. First day on the rear wheel, it made a ton of noise, which settled down and now only comes when the wheel is significantly loaded, i.e.. going up hill and cranking in a low gear. Each hard push down on the cranks causes the groaning. At first I thought the spokes had just loosened a bit because they were new, so I took the wheel back to the mechanic that built them. After re-tensioning them he confirmed it was due to flimsy rim. Builder expressed concern with increasing spoke tension any further due to risk of pulling the spokes through the rim. When you grab two parallel spokes and squeeze together I can see the rim flex, these rims are definitely soft compared to my ENVE 29er rims, and even the Nextie rims the shop was building up. I am curious if anyone else has run into this or if I should just cross my fingers and increase the spoke tension against the builders advice. For reference non drive side spoke tension 18, drive side 22.

  4. #454
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    lol, these 650g carbon rims are the polar opposite of "flimsy". I'm not sure that wheelbuilder knows what a "flimsy" rim is then. These don't really have ANY lateral give, the material doesn't flex or stretch like aluminum, so it's very difficult to get them out of true.

    Have you ever handled one of these things before it's built up?

    How many carbon rims have you built?

    The only possibility is your rim is cracked, which I seriously doubt. I would go feel how "stiff" these spokes feel compared to your other bikes, by grabbing them. I've built wheels that were "correct" according to the spoke tension, but in reality they were nowhere near the tension that they needed to be. Are there any threads showing at the nipples? If there are, that's a pretty good sign the builder got the wrong-sized spokes and doesn't want to wind up the nipples too hard, because the heads will break due to the insertion depth being insufficient.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

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  5. #455
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    Quote Originally Posted by Jayem View Post
    lol, these 650g carbon rims are the polar opposite of "flimsy". I'm not sure that wheelbuilder knows what a "flimsy" rim is then.

    Have you ever handled one of these things before it's built up?

    How many carbon rims have you built?

    The only possibility is your rim is cracked, which I seriously doubt.
    I concur 100 percent.

  6. #456
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    I don't see it affecting the rear end so much, but this isn't going to be the stiffest BB junction, as the tube connects in the middle and doesn't really have anything reinforcing it at the sides. That's a hell of a long BB spindle that will flex IMO when force (pedaling) is applied. The longer the lever arm, the easier it is to flex. This as oppose to a carbon BB that flares the downtube to a width that matches the BB length, where the interface will be much stiffer. I'd think this would cause the front and rear end of the bike to flex a bit, with respect to each other. Don't know if it would cause just the wheel to flex, as the chainstay appears to have a stiffening brace welded in there, but the BB junction has me thinking that if it's going to flex, that'd be where it happens.

    This reminds me of the contrast of an old Raleigh M80 bike with flared (RAD type) tubing that was as wide as the BB at the junction. That thing was steel and stiff as hell, like riding on a rock. Way way over the top in terms of frame-stiffness IMO.

    Surly frames are definitely not the stiffest (not like an aluminum bike) and the wider you make it, the more loosey-goosey it gets. A through axle can help, but it assumes the frame is stiff enough to not allow any flex.


    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  7. #457
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    Without seeing the rim personally I wonder if this is a faulty rim ?

    Maybe a Friday afternoon one missing a layer in the layup ?

    Cracked internally ?

    I too have never heard of carbon rims being described as "flimsy". Least of all fat bike rims .

    The worst I've heard is "fragile" applied to the HED Big Deals (apparently they are designed and built for snow use and not much else ???)

    But these Chiner rims, "flimsy" or "flexy"? Nah something has got to be wrong somewhere.

    You can rail in these puppies as just a rim never mind as a wheel and they take it all. Unlike their alloy counterparts. Just search YouTube.


    Fat Biker

  8. #458
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    Thanks to those of you trying to help! Both rims (unbuilt) straight out of the box standing up on floor could be easily flexed with one hand pushing down and moderate pressure. I could also flex inner and outer surface together (like squeezing a sandwich), not bead lock area. I was hoping once built the spokes would make them stiffer, but I did have my reservations. My Enve rims by contrast could be sat on unbuilt with no flex. Wheels were built up by a reputable local wheelbuilder and checked by coworkers. Rims weighed the advertised 650g. At this point I'm confident it's the rims that are the issue. What I am trying to figure out is have others ran into this issue? Stock wheels were silent btw.
    Last edited by slick50; 12-19-2015 at 09:42 AM. Reason: Add

  9. #459
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    I've had 2 sets and I could flex the bulge around the bead seat with my thumb a little on all of em but the rims as a whole where very stiff before and after builds.

  10. #460
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    Bummer, guess I got a bad batch.....

  11. #461
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    I think it's safe to say nobody has encountered that. Again, it's the polar opposite of how these rims are. This is how much clearance I have with my Dillinger 5s, and I don't rub. My Revolution 2.0/1.5/2.0 are some of the flexiest spokes out there too. I actually have significantly less than the 1/2 inch I said before, more like a quarter at best and these tires would not work on an aluminum rim for two reasons, one, most arent set up for tubeless and won't lock in place straight and two, the carbon rims are so much more true and hold their shape so much better (stiff). In fact, if I was rubbing, it'd be pretty obvious. I got a few layers of stickers on there to provide warning if it does.

    Light-Bicycle fat 90mm carbon rim.-image.jpg

    The part that the tire rests on and the bead lock doesn't have to be very thick or strong, so it's not. The spoke bed on the other hand, that has to be strong, as your hubs are basically "suspended" by the rim at any given time, kind of like a suspension bridge, but all this has nothing to do with the lateral rigidity of the rim. If there really was that much flex going on, there is no way in hell I could run my tires without sawing through my chainstays.

    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  12. #462
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    Quote Originally Posted by slick50 View Post
    Thanks to those of you trying to help! Both rims (unbuilt) straight out of the box standing up on floor could be easily flexed with one hand pushing down and moderate pressure. I could also flex inner and outer surface together (like squeezing a sandwich), not bead lock area. I was hoping once built the spokes would make them stiffer, but I did have my reservations. My Enve rims by contrast could be sat on unbuilt with no flex. Wheels were built up by a reputable local wheelbuilder and checked by coworkers. Rims weighed the advertised 650g. At this point I'm confident it's the rims that are the issue. What I am trying to figure out is have others ran into this issue? Stock wheels were silent btw.
    I have had 6 of these rims over varying times. The inner surface where tape would go will flex, however the outer surface will not flex. A standalone rim, standing upright, pushing down on the beads will flex. I think that's an unrealistic test. Aluminum will just bend and/or break once bent to far. When "squeezing like a sandwich", the inner surface flexes, I do not think the outer surface is budging. If it truly is, the maybe it is a bad rim, but I have to think it is not. I think comparing it to a Enve rim is unfair, way less surface area to do a true comparison. I've had Roval carbon (several models) and LB carbon (also several models) rims that can NOT be (sandwich) squeezed together, but there is simply less surface area to do that.

  13. #463
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    As a follow up, I decided to start over and re-tape both of my LB 90mm rims and run the tape all the way to the edge of the bead shelf. For this round, I used 3M 8087 75mm wide tape so there is a large overlap in the middle.

    Light-Bicycle fat 90mm carbon rim.-lb90_3m8087tape.jpg
    I then put a tube in and mounted two older, loose fitting tires and left them inflated at 15 PSI overnight to flatten the tape.

    Observations:
    1) I suck at applying fat tape. Lots of air bubbles and wrinkles.
    2) The bead shelf/tire interface on my LB 90s is not as tight as I would like. I can install & remove new VanHelgas without too much struggle or drama. My one year old Dillinger 5s come off very easily...way too easily to give me any confidence that they would work at 3-4 PSI. Crap.

    Questions:
    1) Has anyone had to build up the diameter of the bead shelf of their LB 90s with tape?

    I re-mounted the VanHelgas after seeing that the D5s were too loose. They popped into place nicely just like the first time I mounted them. I also used 6oz of Stans vs 4oz this time. The real test will be when I drop the pressure to 4 PSI and ride them on snow.
    Eat Food. Chop Wood. Ride Bike.

  14. #464
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    Quote Originally Posted by CyclingJunkie View Post
    As a follow up, I decided to start over and re-tape both of my LB 90mm rims and run the tape all the way to the edge of the bead shelf. For this round, I used 3M 8087 75mm wide tape so there is a large overlap in the middle.

    I then put a tube in and mounted two older, loose fitting tires and left them inflated at 15 PSI overnight to flatten the tape.

    Observations:
    1) I suck at applying fat tape. Lots of air bubbles and wrinkles.
    2) The bead shelf/tire interface on my LB 90s is not as tight as I would like. I can install & remove new VanHelgas without too much struggle or drama. My one year old Dillinger 5s come off very easily...way too easily to give me any confidence that they would work at 3-4 PSI. Crap.

    Questions:
    1) Has anyone had to build up the diameter of the bead shelf of their LB 90s with tape?

    I re-mounted the VanHelgas after seeing that the D5s were too loose. They popped into place nicely just like the first time I mounted them. I also used 6oz of Stans vs 4oz this time. The real test will be when I drop the pressure to 4 PSI and ride them on snow.

    I think your skills of applying tape is fine. Some tapes stretch easier and can avoid wrinkles, but as long a good portion at the edge is sealed down, you should fine. The valve hole looks suspect at the circle edge though. But it depends on the type of stem you use, O-ring style may seal it, but if it's the tapered rubber plug, it looks like there is a spot for air or sealant to get through on the edge. I now heat up a small taper punch or awl and poke through leaving a small round hole and then force the stem through that. I generally use tapered rubber plug stem, ie. Stan's style. I now use 8898 tape for my rims and in the case of LB 90mm, I used 1" tape over each row of spoke holes, pulling extremely hard and making it a tight wrap. I over lap about 8 inches.
    Light-Bicycle fat 90mm carbon rim.-s-l1600.jpg
    I then use a heat gun to warm the tape and make sure its down or use a tire/tube with pressure in a warm environment. No tape anywhere else. Seals great and it's neat and wrinkle free. You could do that and then also apply tape at the bead seat to build up as necessary for your tires. I use the Spec Ground Controls and those tires have an extremely tight bead and do not require any build up.

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