Results 1 to 19 of 19
  1. #1
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2012
    Posts
    180

    Wide rims, stiffness, tire clearance questions

    Hello, I recently purchased a Supersix Evo (2014), and I am disappointed that tire clearance is an issue. I was used to running 25mm Conti 4ks which measure 27.5 or more on my wide rims on the Caad9, and now clearance is an issue. On my Pacenti SL23 v2 rims, the 23mm version of the contis measure a whopping 27mm. It isn't a terribly stiff rim. On my xc279 rear wheel, it measures just about 25mm.

    Anyway, I am getting frame rub on the chanstays. I am careful to use 3M protectant tape, but it has already rubbed through the paint to the carbon in one small spot. I don't want to keep this bike if I have to run old school narrow rims and narrow tires. With the kinlin rear, it is about 4mm of clearance on both sides. Less with the Pacenti v2. I am wondering how much lateral stiffness comes into play. I am 185 and a fairly powerful climber for my weight, and I think that is when the rubbing happens on the chainstays. The Pacenti are not stiff and even the slightest turn with the spoke wrench moves it a decent amount.

    I am looking at maybe building with the offset Kinlin XR31T, and wondering if that might be a significantly stiffer rim to where the wheel will not move side to side and cause rubbing.

    1. Does this particular rim seem like a laterally stiffer option?

    2. Anyone know how tires measure out on this rim(conti 4ks 23mm)? If it is 27 on a 20.5mm internal rim, and 25 on a 17mm internal, this might be near 25.5-26, which might be okay if the rim does not flex and move side to side.

    3. When I build, should I use a thicker DS spoke, or will cx rays be sufficient(if I get the BDOP kit), or Race DS, and Laser NDS?

    4. Anything I am missing?

    I don't want to get rid of the EVO, but I am not going back to 2010 wheel/tire technology just to keep it!

    Thanks

  2. #2
    RoadBikeReview Member
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    4,643
    What is the spoke count of your current wheels? The best thing you can do to prevent lateral wheel flex is a higher spoke count. Thicker spokes may help, but not as much as MORE SPOKES.

    If you are a powerful rider and want to keep that bike, go with a 32 spoke rear wheel, 24 spoke front wheel. Trust me, you won't notice a difference in speed.

    Here is a great article on the subject that's worth reading in its entirely:

    Debunking Wheel Stiffness - Slowtwitch.com
    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein

    "Beware of geeks bearing formulas."
    -- Warren Buffett

    "Education is what you get when you read the fine print. Experience is what you get when you don't. -- Pete Seeger



  3. #3
    changingleaf
    Reputation: changingleaf's Avatar
    Join Date
    Aug 2009
    Posts
    527
    I don't think a different rim or spokes or lacing are going to make much difference. You don't have a lot of clearance and if you have rubbing at the chainstays it's primarily the frame flexing in my experience. Though, I have also seen crappy external cam skewers that shift in the rear dropout and cause the tire to shift closer to the drive side chain stay. If you're not running an internal cam skewer already try something like a shimano skewer and see if it helps.

    I have the 2015 Evo by the way and I agree that it does not have as much clearance as I would like, though some bikes are worse.

  4. #4
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2013
    Posts
    241
    I have a 2014 EVO and run 32 spoke wheelset (DT240S hubs and Hed C2 23mm wide rims). I cannot run 25mm Conti GP 4-Seasons as they will rub and last year I road at 185 lbs (this year I am down to just under 180).

    With 23mm Conti GP4000II they run fine. But, you won't be able to run a 25mm wide wheel with the bike, I have a HED front that is a plus rim (25mm wide) with a 23mm Conti GP4000II tire on it and the tire is wider than the 23/23mm combo by a few mm (both eye test and measuring with a set of calipers). This is for my other bike so I don't worry about it.

    You can either:

    - Run a 25mm wide tire of another brand as those aren't as wide as Continentals
    - Run a 23mm wide tire of any brand you choose
    - Get a different bike (I believe 2016 and newer Evo's have wider chainstays)

    I wouldn't want to run a 25mm or wider rim on my bike as I pretty sure the chainstays would rub.

  5. #5
    RoadBikeReview Member
    Reputation:
    Join Date
    May 2010
    Posts
    476
    Cannondale can be stingy on tire cleance. I think the High Mods are even worse.

    We decided if you can't run wide rims and wide tires, go with wide rim and a 23 tire, rather than narrow rim and wide tire.

  6. #6
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2012
    Posts
    180
    Thanks for the suggestions. Both rear rims are of the 28h flavor. 32 sounds like crazy overkill, but may be an option. It sounds like others were able to get 23s on wide rims to fit, so hopefully I can make that work. I may just have to keep an eye on my 3M paint protectant film and keep changing it out. So an asymmetric deeper rim won't help much?

  7. #7
    RoadBikeReview Member
    Reputation:
    Join Date
    Oct 2013
    Posts
    2,044
    As per the article, a stiffer rim will cause more movement. ... you need a wishy washy rim.
    BANNED

  8. #8
    RoadBikeReview Member
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    4,643
    Quote Originally Posted by duriel View Post
    As per the article, a stiffer rim will cause more movement. ... you need a wishy washy rim.

    More SPOKES my friend. SPOKES!
    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein

    "Beware of geeks bearing formulas."
    -- Warren Buffett

    "Education is what you get when you read the fine print. Experience is what you get when you don't. -- Pete Seeger



  9. #9
    RoadBikeReview Member
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    4,643
    Quote Originally Posted by BLD25 View Post
    32 sounds like crazy overkill......
    No it isn't. Depending on your weight, it may be overbuilding....or not. Regardless, that isn't a problem. As I said, it won't noticeably slow you down. Remember that wheels with lower spoke counts must have heavier, stiffer rims in order to withstand the extra tension over fewer points. And as Duriel said, a stiffer rim will counter intuitively cause more movement.
    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein

    "Beware of geeks bearing formulas."
    -- Warren Buffett

    "Education is what you get when you read the fine print. Experience is what you get when you don't. -- Pete Seeger



  10. #10
    RoadBikeReview Member
    Reputation: velodog's Avatar
    Join Date
    Sep 2007
    Posts
    5,744
    Quote Originally Posted by Lombard View Post
    More SPOKES my friend. SPOKES!
    Yep, from the article...


    Practical Implications and Compromises

    In the past, I did a lot of work with ProTour road teams, and this brake pad rub was a constant point of discussion. The mechanics would say, “The wheels are not stiff enough!” Sometimes they’d increase the spoke tension on all of the wheels to try to help. The real solution – and what you see done by many wheel manufacturers – is a custom spec wheel for the professional teams. You’ll see thicker spokes, higher spoke counts, and brass spoke nipples (which are more tolerant of high tension and poor conditions). They need to bring more spoke muscle to the fight.




    What about you – the ‘average consumer’? If you’re in the fat of the bell curve – middle-of-the-pack age grouper, 5’2” to 5’10”, 110 to 175 lbs… you may very well be just fine on any off-the-shelf wheel.

    I personally have never had an aluminum rim rub my brakes, but I have had issue with carbon rims. For reference, call me a ‘reasonably strong 170 lb athlete’. My old race bike was a carbon frame with low-mounted TT brake. My usual rear wheel was a stock deep-section carbon clincher with 20 thin aero spokes. While climbing very steep hills, the rim would rub the rear brake pads – which were shaved down – and the caliper was open as much as possible without the lever pulling to the bar. What to do? I exchanged the wheel for an identical one – except for the spoke count, which was 24. Interestingly, the brake rub went away. My suspicion is that the stiffness of both parts – the wheels and the frame – play together to make up a total system stiffness. Adding in a few spokes solved my problem.

    Aren’t more spokes and thicker spokes heavier and less aerodynamic?

    Yes, adding more spokes or thicker spokes adds weight and drag. That’s life. On the flip side, you’re losing power by flexing a wheel or rubbing the brake pads. I inquired with several different manufacturers about the aerodynamic cost of adding a few spokes (i.e. using 24 rear spokes instead of 20). All replied with the same answer: The aerodynamic cost is minimal. The weight penalty is minimal. You do gain a little bit of radial stiffness – which could be seen as ride harshness – but I argue that this is a non-issue, short of extreme cases.

    Why, then, don’t they use more spokes? Two words – fashion and weight. Fewer spokes look cool, and look better on-paper to the gram counters. I agreed to keep any official comments off-the-record from all manufacturers in this regard… but all of them had similar answers - sex sells.
    Too old to ride plastic

  11. #11
    RoadBikeReview Member
    Reputation:
    Join Date
    Feb 2002
    Posts
    20,428
    Quote Originally Posted by BLD25 View Post
    32 sounds like crazy overkill
    Define crazy. You mean crazy that if you break a spoke you will experience a lot less rim deformation? Crazy in that the wheel will be laterally stronger? Crazy in that spoke tensions can be lower and therefore reduce the risk of rim cracking? Crazy in that the wheel will be more durable? That's a lot of crazy indeed.

  12. #12
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2012
    Posts
    180
    Quote Originally Posted by Kerry Irons View Post
    Define crazy. You mean crazy that if you break a spoke you will experience a lot less rim deformation? Crazy in that the wheel will be laterally stronger? Crazy in that spoke tensions can be lower and therefore reduce the risk of rim cracking? Crazy in that the wheel will be more durable? That's a lot of crazy indeed.
    Maybe crazy sarcasm?

  13. #13
    RoadBikeReview Member
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    4,643
    Quote Originally Posted by Kerry Irons View Post
    Define crazy. You mean crazy that if you break a spoke you will experience a lot less rim deformation? Crazy in that the wheel will be laterally stronger? Crazy in that spoke tensions can be lower and therefore reduce the risk of rim cracking? Crazy in that the wheel will be more durable? That's a lot of crazy indeed.
    And that's the kind of crazy I like!
    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein

    "Beware of geeks bearing formulas."
    -- Warren Buffett

    "Education is what you get when you read the fine print. Experience is what you get when you don't. -- Pete Seeger



  14. #14
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2012
    Posts
    180
    okay, after reading the article, it has quite a bit to digest. I am not an expert, of course, but I do like tinkering with bikes and wheels, and I am a science teacher, so I have some basic knowledge of what they are discussing.

    In regards to the lateral stiffness, it seems that they are discussing the problem of brake pad rub. This makes a little more sense as I read the article. It also appears that if the rim is stiff, or if the whole wheel is laterally stiff, chainstay rub is not an issue as it is in the middle of the system, and the opposing end(brakes) are where the issue arises. I have more than enough clearance at brakes and seatstays, but the chain stays are the place where rub is an issue. In my opinion, it is due to not enough NDS tension, and also my lack of building skill as a novice with around 10 wheel builds. I have also read that some EVOs have a slight off center in their rear triangle which can lead to a less than optimally dished wheel. This is beyond my level of investigation at this point.

    So, while some have suggested the 32h wheel as a remedy, that might be a good answer. I have not ruled this out yet. However, after reading that chainstay rub shouldn't be an issue as it is in the middle of the system, a properly built, stiff, 28h wheel with a deeper rim and proper DS/NDS tension might be a good option as well. This brings me back to the xr31T asymmetric rim. A couple people have mentioned in the article that more spokes are the answer, but other answers were provided by the author as well in the terms of larger spokes, and better spoke tension. Since I don't need it to be so stiff as to be perfect in the brakes, I just need one that holds together well under load by having good overall tension.

    So, if I were to use the XR31T Asymmetric rim, and a slightly thicker spoke(CX or Race), on DS, and thinner spoke(CX-Ray or Laser on the NDS), that should at least IMPROVE what I have going right now right?

    Also, in the meantime, I could add a thicker spoke to the DS side of my rear wheels(The Pacenti SL23 is 28H and has Wheelsmith DB15 (1.7mm) spokes all around, and the Kinlin XC279 has lasers all around (1.5mm)), and achieve a little more stiffness laterally for just a few bucks, right?

    I appreciate the help!

  15. #15
    RoadBikeReview Member
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    4,643
    BLD25,

    I have to ask what are you measuring your spoke tensions with? A conventional build with an 11-speed freehub, symmetrical rims and the same spokes on DS and NDS will give you sufficient NDS tensions provided you use a rim that is capable of 120kgF. I tension my wheels with a bare wheel DS tension of 130kgF which brings the NDS to a more than adequate 55kgF. Subtract about 10kgF with a tire inflated to 100PSI and you still have sufficient tensions. If your NDS tension were really low enough to cause wheel flex, the bike would be unrideable - just to put things in perspective.

    Thicker spokes on the other hand may help your problem. Ditch the skinny spokes and go with a double butted 1.8mm spoke like the DT Competition. Do these on BOTH SIDES. If you want a bladed spoke, the DT Aero Comp is a good choice. DT Aero Lites are too skinny! DT Competitions are your best bang for the buck. Bladed spokes made building easier as you can immediately see spoke windup.
    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein

    "Beware of geeks bearing formulas."
    -- Warren Buffett

    "Education is what you get when you read the fine print. Experience is what you get when you don't. -- Pete Seeger



  16. #16
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2012
    Posts
    180
    Okay, so after thinking about it more, reading the posted article about stiffness, and reading replies, I think I am grasping this more. I don't have an issue at the brakes. It may rub from time to time, but nothing that I notice. After reading the post about wheel stiffness, that is the place to find movement. I took my bike in the garage and pushed and moved on the frame and wheel and watched what happened, and sure enough, pushing on the frame sideways caused movement at the top of the wheel near the break pads, but not really much change at the stays. Even pulling on the back of the wheel pretty hard causes some movement at the stays but not much.

    So what causes rubbing on the chainstays then? Well, to be honest, it would probably be the result of a poorly built wheel. And since I am the builder, I can gulp a bite of humble pie and say I still have some ways to go. It could be from not being tensioned properly and being not true and moving more side to side. Sure there could be frame flex, but EVOs are known to be stiff, strong frames, and not noodles, so I doubt that is the ultimate problem. Hopefully, building some of my wheels with some thicker spokes will allow me to get a little more even tension and strength and prevent some of these problems.

    thanks for the help!

  17. #17
    changingleaf
    Reputation: changingleaf's Avatar
    Join Date
    Aug 2009
    Posts
    527
    You may not have built the best wheel, but the frame can flex when a lot of force is applied to the pedals, such as standing up on a hill or sprinting.

    To test the flex at the chain stay stand on the right side of your bike and hold both the brake levers tight. Place the right crank horizontal to the ground and push down on it with your foot and you will see the frame move toward the tire at the chain stay.

    The frame is moving inward relative to the wheel hubs. The hubs are horizontally in line with chain stay area so they flex around it, not in line with it.

    So, when you push vertically down on the pedal it pushes the frame inward to the left while the the tires are held stationary on the ground. The wheel will flex around the hub, so as the tire is stationary on the ground and the frame pushes in the wheel will bend from the ground up to the hub, not from the chain stay area.

    The force on the pedals also pulls the wheel forward and can sometimes cause the hub to slip in the drop outs, which moves it slightly out of center. Skewers with internal cams can prevent this.
    Last edited by changingleaf; 3 Weeks Ago at 05:58 AM. Reason: clarity

  18. #18
    RoadBikeReview Member
    Reputation: Lombard's Avatar
    Join Date
    May 2014
    Posts
    4,643
    I am really surprised that a 2014 SuperSix Evo has this much flex. My 2014 Cannondale Carbon is pretty stiff.

    Slippage in the dropouts? Man, that would be a really strong or heavy rider unless the QR wasn't tightened sufficiently!
    “Statistics are like bikinis. What they reveal is suggestive, but what they conceal is vital.” -- Aaron Levenstein

    "Beware of geeks bearing formulas."
    -- Warren Buffett

    "Education is what you get when you read the fine print. Experience is what you get when you don't. -- Pete Seeger



  19. #19
    RoadBikeReview Member
    Reputation:
    Join Date
    Jul 2012
    Posts
    180
    Quote Originally Posted by Lombard View Post
    I am really surprised that a 2014 SuperSix Evo has this much flex. My 2014 Cannondale Carbon is pretty stiff.

    Slippage in the dropouts? Man, that would be a really strong or heavy rider unless the QR wasn't tightened sufficiently!
    Yeah, this isn't a frame known for flex. My guess is a wheel not properly built but I will keep practicing.

Similar Threads

  1. rims....how wide is too wide?
    By toddre in forum Cyclocross
    Replies: 11
    Last Post: 02-19-2014, 09:27 AM
  2. Isn't wheel lateral stiffness be more important that BB stiffness?
    By Bridgey in forum Bikes, Frames and Forks
    Replies: 17
    Last Post: 11-10-2013, 02:35 PM
  3. What is a wide rim? 22-23mm wide? What rims?
    By aclinjury in forum Wheels and Tires
    Replies: 9
    Last Post: 02-07-2012, 03:59 PM
  4. Tire sizes for 24.2mm wide rims
    By camscandalous in forum Wheels and Tires
    Replies: 3
    Last Post: 10-19-2008, 06:18 PM
  5. Crankset stiffness vs frame stiffness
    By Anders Moll in forum Components, Wrenching
    Replies: 2
    Last Post: 09-29-2005, 07:36 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •