Bontrager X lite Wheels

Discussion in 'Cycling Equipment' started by cohiba1223, Oct 30, 2006.

  1. cohiba1223

    cohiba1223 New Member

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    I just purchased a set from a friend ... brand new 2007. First time I used them was for the century I did yesterday. I finished in just under 6 hours, 5 hours on the bike. Had to do 38 miles on my own because my group dropped off at the 100K, 62. These wheels kick ass, in the wind they performed very well, with the wind it was effortless to get them up to 30+ mph. I used to have the Bontrager Race and what an upgrade for the money. It is so easy to spin these wheels up to fast speeds. My max on the Race wheels was around 32 mph, I have hit 34 with the X lite and only had them for 1 week. I strongly recommend them.
     
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  2. carbonguru

    carbonguru New Member

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    How much did your buddy sell the wheelset to you? They are very nice looking wheels.



     
  3. cohiba1223

    cohiba1223 New Member

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    I was able to pick them up for $500 with Race X Lite Tires
     
  4. carbonguru

    carbonguru New Member

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    WOW! Great deal!!!



     
  5. alienator

    alienator Well-Known Member

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    It's nice you like your wheels, but I doubt the increased speed is due to anything related to the wheels. More than likely, the increased speed is from you being psyched about the wheels.

    You are talking about Race X Lites, right?

    I had a pair of Race X Lites, and while the hub internals were made by DT and rolled well, the rest of the wheel was non-spectacular. This was doubly the case when the rear DS hub flange self destructed after less than a year. Comparing how I ride with the wheels that replaced the Race X Lites--a set of Crostini R3.1/3.2 rims laced 24f 2x and 28r 2x--there is absolutely no difference in speed. None. And the Crostinis have a lower profile rim, to boot. My Crostini set is laterally stiffer.

    Speed increases from different wheels are only gonna come with muy deeper rims, everything else being equal. Even with deeper rims, the difference is smallish, like about 0.5mph at 25mph with the best deep, aero wheels. The math behind that idea is backed up by my experience with my Reynolds Stratus DV's. They have 46mm rims, and any differences I see are really only noticeable when the pace is wicked up--20-22+mph--or when there's a strong headwind. In those cases, the speed improvement is still small.

    Aerodynamically there is about nothing special about the Race X Lites, certainly nothing that would account for speed increases....unless the wheels you previously used had no lube in the hubs.
     
  6. cohiba1223

    cohiba1223 New Member

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    Thank you for your opinion, but I believe the 300+ grams that I saved in changing from race to Race X lite had a lot to do with my ability to spin faster and increase speed with ease.


    ben
     
  7. alienator

    alienator Well-Known Member

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    Well, you'd be wrong, there, because wheel weight--actually, a wheels rotational moment of inertia--has almost no influence on wheel performance. Human acceleration of bicycles is so small that the differences in rates of acceleration with wheels having a 500g weight difference is only a few tenths of a percent. Even with wheels having a weight difference of 1000g, the difference is still very small. In fact, the only time that light wheels start to pay any noticeable dividends is when the climbing grade starts to get really steep, on the order of 10% or so. Until then, aero concerns dominate.
     
  8. vadiver

    vadiver New Member

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    Hate to ask this, but did you change wheel size on your computer? Or are you using the exact same tire on the rim?
     
  9. ryanspeer

    ryanspeer New Member

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    Is this based on fact, guessing, or repetition of rhetoric you've heard from others? The only reason I ask is that in my personal experience, the difference made by lighter weight wheels is quite drastic.

    Bike A) approximately 20.5 lbs. Ultegra 9-speed, average weight bars, stem, seat, seatpost, etc. Heavy wheels (approx 2200grams w/o tires, tubes or cassette). Extra weight accounted for primarily in the wheels and and secondarily in the frame.

    Bike B) 18.5lbs. Ultegra 10-speed, average weight bars, stem, seat and seatpost. Comperable-weight tires & tubes. Approximately 1850gram wheels.

    Bike A was all I was previously used to and figured that climbing had to be that difficult. Purchased Bike B and proceeded to ride both around my hilly neighborhood, quickly jumping off of Bike B to Bike A and then back again. The difference climbing a small grade, sprinting out of the saddle, etc., was simply enormous. The frames are both very very stiff, but both bikes performed entirely different. Bike B with the lighter overall weight (most of which was accounted for in the wheels) made Bike A feel like a sluggish 4-cylinder truck with a full load of firewood in the back while pulling a small camping trailer.

    I proceeded last Friday to ride Bike B on my normal route that I'd taken only Bike A on previously. The weather was cold, I felt physically slightly sub-par generally speaking, and it was a slightly windy day. Not "blustery" per se, but definitely not the normal environment I'd previously been used to riding Bike A in. By the end of the ride, I'd averaged approximately 1 mph faster than I'd ever ridden this exact same route before - and THAT was with me lolly-gagging for a solid 6-7 minutes at 10mph for a stretch while watching scenery that I'd never taken time to slow down and enjoy before.

    My personal experience leaves no doubt whatsoever in my mind that the weight (especially rotational) weight makes a huge difference.
     
  10. vadiver

    vadiver New Member

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    Actually I ride on both Race Lites and Race X Lights with the same brand/model of tire with about the same milege on each. The only difference between is the rin (and hub/spokes if they are different between the two).

    I have a 16 mile (45 minute) route that I use as my base for fitness that I a couple of times a month. I alternate these two wheels and see no difference on this route over multiple rides. I see a greater difference based on the number of times I get stopped at a stop light (speed of 0 do not contribute to my computers average speed) and have to accelerate from zero and weather more than anything else. (I monitor my performance with both clock time and average speed and it is the same regardless of the wheels).
     
  11. ScienceIsCool

    ScienceIsCool New Member

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    It's fact. Of all your kinetic energy while riding (bike, rider, clothing, accessories), only 2-3% of it is in the wheels. Yes, that takes into account the moment of inertia which contributes less than 0.5% of overall kinetic energy.

    I can go into any specifics if you wish, but I also discuss some of this on my website near the end of the paper. The conclusion I've come to is that wheel weight makes a difference, but it is an exceedingly small one. A 50% change in wheel mass makes ~1% change in acceleration and energy.

    John Swanson
    www.bikephysics.com
     
  12. cohiba1223

    cohiba1223 New Member

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    I am sorry for causing such commotion, I just wanted to share how happy I was with the new wheels. I feel that almost a 1lb difference in rotational weight is huge, and it was confirmed by all the LBS guys, including a Cuban National Team rider. I rode my Race this morning for training and there is a large difference my good friends. Anyways stay on the bike and watch out for those windy days.
     
  13. ScienceIsCool

    ScienceIsCool New Member

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    I think that's the most important thing of all - you enjoy your new wheels and are happy with them. I don't think we agree on why you are riding faster, but it really doesn't matter. Cheers!

    John Swanson
    www.bikephysics.com
     
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