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  1. #1
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    Blur XCc Conversion - RP23 Volume Reduction?

    I had to reduce the RP23 travel by 10mm, which is sort of a lot out of a total of 35mm. Would it make sense to put in the fox volume reduction kit to increase the shock spring rate?

    If anyone is curious, tires are 2.2" Continental X-Kings. If I like the setup, I might go to 1x11 drive train to free up room for rear travel.

  2. #2
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    I presume you are using a 3mm shock spacer to reduce the wheel travel by 10mm?.Might as well ride a hard tail if you've reduced the shock stroke by 10mm.Assuming you have put a 3mm shock spacer in it could be a good idea if you have also upped the pressure to smooth out the transition to bottoming out. if you haven't and still only just reach the reduced fulll travel then I wouldn't worry.In some of the older xc supension designs reaching ful travel was on the wishlist rather than reality so the shim is for peice of mind.
    If that's not the case it doesn't hurt to experiment. Adding air vol spacers ,while droppping the pressure slightly, will use similar travel but make the shock more progressive. On some designs this will feel like it has more travel.

    In my experience on 26" conversions,if you are going to either compromise rear wheel travel or handling, it's always better to just leave the rear wheel at 26" . It's much harder to detect any rollover benefit from the larger wheel on the rear than on the front.The lower BB height and slacker front outweighs any 650B benefit on the rear. IMHO throw a Xking 2.4 racesport on the rear. It's tall and narrow, with a few extra psi, is as quick with more cush and rollover than the xking 2.2.

  3. #3
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    I did not have to reduce the travel on my 2012 XCc. I use 2.25 Schwalbe Ra Ra's mounted on AM 650bxc wheels.
    As far as the comment about using a 26" wheel in rear is ridiculous, I almost believe the Blur was made for 27.5,rather than the 26" wheels, you'll have to ride one to understand. I've ridden tons of bikes of all genres and wheel sizes in my 30+ years of mountain biking, and this is the best one yet.

  4. #4
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    Quote Originally Posted by Hurricane Jeff View Post
    I
    As far as the comment about using a 26" wheel in rear is ridiculous,
    What's ridiculous about it.

    Read a bit slower.
    I said.

    [if you are going to either compromise rear wheel travel or handling, it's always better to just leave the rear wheel at 26" ]

    If you feel neither is compromised on this design then fine. I don't have one to compare. I'm only going from the OP which was a little confused, and if you say unnecessary.

    I've currently got four bikes which are capable of running 650b rear. I only ride one of them full 650b as handling is compromised on the rest of them. None of them are only 100mm of travel and all run high volume 26" rear tires ,like the Xking 2.4. On these bikes I can't notice any difference in rollover running a 26" rear vs 650B.

    Ridiculous or reality?

  5. #5
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    I read slow alright, maybe you should ride a converted Blur. Some that have converted their Blurs, have had to slightly reduce their travel( don't know why some do, some don't, maybe wheel/ tire combos) but I never heard any negative affects, reducing travel by 10mm is not going to make or break your ride.
    I know that maybe you were generalizing on converted bikes and I get it, but if you run a 26" wheel, than its not a conversion. The Blur is a totally different, better bike converted, that when ran with 26" wheels.

  6. #6
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    Quote Originally Posted by gvs_nz View Post
    I presume you are using a 3mm shock spacer to reduce the wheel travel by 10mm?.Might as well ride a hard tail if you've reduced the shock stroke by 10mm.Assuming you have put a 3mm shock spacer in it could be a good idea if you have also upped the pressure to smooth out the transition to bottoming out. if you haven't and still only just reach the reduced fulll travel then I wouldn't worry.In some of the older xc supension designs reaching ful travel was on the wishlist rather than reality so the shim is for peice of mind.
    If that's not the case it doesn't hurt to experiment. Adding air vol spacers ,while droppping the pressure slightly, will use similar travel but make the shock more progressive. On some designs this will feel like it has more travel.

    In my experience on 26" conversions,if you are going to either compromise rear wheel travel or handling, it's always better to just leave the rear wheel at 26" . It's much harder to detect any rollover benefit from the larger wheel on the rear than on the front.The lower BB height and slacker front outweighs any 650B benefit on the rear. IMHO throw a Xking 2.4 racesport on the rear. It's tall and narrow, with a few extra psi, is as quick with more cush and rollover than the xking 2.2.
    It was 10mm reduced shock travel - it was way more than I needed. I've since reduced to ~4mm. I've tried with and without volume reducer. Rides nicer with volume reducer in, able to run lower PSI and makes for a smoother ride. I can't tell at all that I'm missing any travel.

    I've got a few rides on the bike now. The bigger wheels are nice, but mainly because it narrows the difference between the bike I ride most: a 29er hard tail. Difference is subtle, 26 -> 27.5 is hard to get too worked up about. 29 on the other hand is a big difference, just started riding one a couple months ago.

    The thing I like most is reduced pedal strikes from raising BB.

    Bike handles very nice, maybe slightly better as 650B. Fun trail bike and I'm sure I'll use it for the occasional race on the rare course where a FS is a benefit. Maybe endurance stuff too.

  7. #7
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    Quote Originally Posted by Hurricane Jeff View Post
    I did not have to reduce the travel on my 2012 XCc. I use 2.25 Schwalbe Ra Ra's mounted on AM 650bxc wheels.
    As far as the comment about using a 26" wheel in rear is ridiculous, I almost believe the Blur was made for 27.5,rather than the 26" wheels, you'll have to ride one to understand. I've ridden tons of bikes of all genres and wheel sizes in my 30+ years of mountain biking, and this is the best one yet.
    I agree - it does seem blur was made for 650b. I was a little intimidated adding shock spacers. But I picked out a few nylon washers from Ace HW, put a slit in them with a box cutter. 3min to unscrew air canister and clip them on. The air volume reducer is a nice touch, but definitely not mandatory.

  8. #8
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    Just because you can't feel the difference as much from 26" to 27.5 as you do riding a 29er, isn't a bad thing. People get duped into thinking that there is not much of a difference, that it doesn't matter much. Bigger is not always better and sometimes more subtle changes are better, if bigger wheel sizes are better, how come off-road trucks, buggies and motorcycles have not gone with this philosophy? certainly motorcycles that race Baja or backwoods enduros would benefit, right? has technology just not caught up yet? No, they have tried bigger and smaller wheel diameters and found out which works best, your seeing the same thing in mountain bikes. When 29ers came along, there was a change, maybe even did some things better than 26ers, better rollover, carries momentum better,etc, but you gave up stiffness, quickness and weight. I'm not saying 29ers are all bad and I understand some of the merits, but 27.5 has most of those merits plus more. What your going to see, and your starting to see now is 27.5's overtaking not just 26ers, but 29ers as well. When people start riding them, instead of the people who have never ridden them start commenting, you'll see for yourself. It sounds to me that the ones who talk down 27.5's have never ridden one.

  9. #9
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    Quote Originally Posted by Hurricane Jeff View Post
    Just because you can't feel the difference as much from 26" to 27.5 as you do riding a 29er, isn't a bad thing. People get duped into thinking that there is not much of a difference, that it doesn't matter much. Bigger is not always better and sometimes more subtle changes are better, if bigger wheel sizes are better, how come off-road trucks, buggies and motorcycles have not gone with this philosophy? certainly motorcycles that race Baja or backwoods enduros would benefit, right? has technology just not caught up yet? No, they have tried bigger and smaller wheel diameters and found out which works best, your seeing the same thing in mountain bikes. When 29ers came along, there was a change, maybe even did some things better than 26ers, better rollover, carries momentum better,etc, but you gave up stiffness, quickness and weight. I'm not saying 29ers are all bad and I understand some of the merits, but 27.5 has most of those merits plus more. What your going to see, and your starting to see now is 27.5's overtaking not just 26ers, but 29ers as well. When people start riding them, instead of the people who have never ridden them start commenting, you'll see for yourself. It sounds to me that the ones who talk down 27.5's have never ridden one.
    I think the constraints in motor sports are different. The weight supported per wheel is much different. Plus you have much more horsepower/weight to apply to the problem. So, it seems reasonable you arrive at a much different optimal solution. I do think most MTBers run narrower tires than we should.

    Anyway, I do like the 650b better than 26. It just isn't a huge improvement. And I can see your point that noticing a huge change might not be a good thing.

    For my HT, I can't really see wanting to go back down to 27.5. I think loss of rollover would be pretty noticeable on a HT.

  10. #10
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    For those that have done this conversion I wondering what your thoughts/cautions would be for running the new surly Dirt Wizard 26 x 2.75" on 40mm rims? These massive tires (here: Dirt Wizard 2.75 thread ) are basically 27.5 diameter... but wide with big knobs. I'm measuring just 3" between the stays... thinking it's gonna be darn close. Guessing I'll need to shim??

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