Considering a 20mm TA 29er fork upgrade for an XC race bike- Mtbr.com
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  1. #1
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    Considering a 20mm TA 29er fork upgrade for an XC race bike

    So here is the deal. I have a 2010 Specialized S-Works Stumpy 29er. I have been blown away with the stiffness of this bike even in comparison to my Superfly. I do miss the vertical compliance from the rear triangle that the Superfly featured, as well as occasionally missing the more stable geometry.

    That aside I feel like the stock QR Reba lowers really aren't hacking it. I have never really noticed a fork flex this much at the axle. For reference I am running Edge Composites XC wheels with CK QR hubs, and I actually think the rims are adding to the wimpy feeling at the hub. The rims are just so stiff (as is the Crown Steerer Assembly being carbon and tapered) that I really notice the lowers twisting torsionally when I am blasting super rooty or rocky sections. The stock Rovals feature the OS28 endcaps which are claimed to really aid in the stiffness of the wheels/lowers at the hub which the stock CK hub lacks.

    So the main questions. I haven't laid hands on a current 20mm Thru-Axle Reba, is the new Maxle Lite a direct thread in thru-axle, or the weird older qr style with a seperate QR and axle? I am pretty sure it is the first option. Also in doing the spoke calcs, the spoke lengths turn out to be the same (within a couple of tenths of a mm) so switching hubs won't be a big deal other than unlacing and relacing with new nips and the old CX-Rays.

    Am I crazy? I am not overly concerned about the weight increase. The bike is in the low 22lb range as it is so gaining a half pound wouldn't worry me one bit. Is it a viable upgrade? Would you do it yourself? I am probably going to try it either way. With only needing new lowers, and a hub (and a little labor) I think it would be a worthwhile investment. If Rock Shox was going to offer a 15mm Reba 29er lower I would only need a new axle for my existing hub, but it doesn't look like that is happening.

    Let me know what you all think.
    Last edited by ia_ss157; 08-26-2010 at 06:57 PM.

  2. #2
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    Can't speak for certain, as I haven't tried the new Reba's with the 20mm Maxle, but with my 2007 with 100mm and a Hadley 9mm through axle on front, the whole fork was the problem. I went with a 120mm 20mm throughaxle Manitou Minute 29, and it was much, much better than the Reba. There was just a lot of flex in the stanchions and fork leg in the REBA. Some of that may have been corrected in the Power Bulge design, but I've never had a chance to try the Reba with the power bulge feature.

  3. #3
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    I have a spec SJ comp 29er which I swapped out the stock reba qr lowers for the 20mm maxle light and 20mm hope hub. The difference was night and day. I will never ride QR again.

  4. #4
    TR
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    I will more than likely be the sole nay sayer here but I have ridden standard QR, 9mm QR and 15mm QR.
    I could tell no difference whatsoever for general XC riding.
    I have stuck with standard QR and even went as far as to get Fox to install standard QR lowers on my tapered F29 so that I could have both my bikes running the same type of drop out and for ease of swapping wheels between the bikes if needed.

    If your riding is something more than general XC on groomed trails then this answer may be entirely different.

  5. #5
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    Critical info

    You don't mention your riding weight, nor do the other posters. IMO that + of course your riding style makes all the difference.

    I weigh 200 lbs and ride singletrack trails, not groomed but no huge drops either. I went from 2008 Reba 100mm QR to 2009 Reba 120mm and it was a huge difference in front end tracking.

  6. #6
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    do it, 20mm TA forks rule

  7. #7
    jms
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    You're not alone

    Quote Originally Posted by TR
    I will more than likely be the sole nay sayer here but I have ridden standard QR, 9mm QR and 15mm QR.
    I could tell no difference whatsoever for general XC riding.
    I have stuck with standard QR and even went as far as to get Fox to install standard QR lowers on my tapered F29 so that I could have both my bikes running the same type of drop out and for ease of swapping wheels between the bikes if needed.
    You're not alone, I came to the the same conclusions and I couldn't agree more.

  8. #8
    AOK
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    Quote Originally Posted by ia_ss157
    Also in doing the spoke calcs, the spoke lengths turn out to be the same (within a couple of tenths of a mm) so switching hubs won't be a big deal other than unlacing and relacing with new nips and the old CX-Rays.
    I'm pretty sure you don't have to switch hubs - I have a set of the Roval Control EL wheels and the front hub can be converted between OS28, 15mm, and 20mm by swapping end caps. I think the caps were ~ $30 when I converted my front to 15mm.

  9. #9
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    Details

    I weigh around 155-160lbs . I ride as aggressively as a carbon fiber race bike can allow. Luckily the Specialized frame is insanely durable (for carbon). The build I have on the bike is as strong as you can get for what it weighs. There isn't a single part on the bike I am scared or worried about breaking so I push myself and the bike hard.

    That being said, I do not huck the bike in any way. I consider myself a smooth rider. This is the first season that I have owned a bike with front suspension and gears in 5 years. Before I owned several rigid singlespeed 26" and 29" bikes. The trails have changed to the point that I do not regularly like to ride them on a rigid SS. I still own one, but ride it 1-2 per month.

    My local trails are root strewn and washed out with a couple nasty rock sections and 1.5-2 foot drops. I know that doesn't sound too intimidating, but over the course of one 11 mile lap, you get pretty fatigued. The race this weekend is 3 laps. I raced that same distance 2 years ago on my first rigid SS 29er and it was tough on your body. I am just hoping that some extra precision will aid in reducing that fatigue.

  10. #10
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    Originally posted by AOK
    I'm pretty sure you don't have to switch hubs - I have a set of the Roval Control EL wheels and the front hub can be converted between OS28, 15mm, and 20mm by swapping end caps. I think the caps were ~ $30 when I converted my front to 15mm.
    I am on Edge Composites laced to Chris King hubs, not the Rovals.

  11. #11
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    Thought for a sec you meant the old Cannondale cyclocross Headshoks with 25mm of travel


  12. #12
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    I just got a 2011 Sj Comp 29er with the 130mm Reba RLT. I am impressed with how stiff the fork is.

    I weigh 185 and ride mostly singletrack. My other bike is an Astrix Rook with a 100mm 05 Reba Race.

    I can stuff the SJ into corners a lot harder than the Rook.

    I say go for it.

  13. #13
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    Yes, 20mm is stiffer torsionally. Yes, it adds precision to the front of the bike.

    Reduce fatigue in an XC race? Hmmm... That's not one that I'd thought of. Possible I guess, but probably not by much.

    At your weight I'd think it wouldn't make that much difference for XC-type stuff.

  14. #14
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    no qr

    I weigh 155 and like to push it at times. TA makes a difference. It is one feature I will not pass up on my new bike purchase.
    Here's to sweat in your eye.

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