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Ask Pinkbike: Whips, Carbon Rims, and Cracked Frames

Jun 30, 2015
by Pinkbike Staff  
Ask Pinkbike Header

Here at Pinkbike we get inundated with all kinds of questions, ranging from the basic "Can I have stickers" to more in-depth, soul searching types of queries like if you should pop the question or what to name your first child. Ask Pinkbike is an occasional column where we'll be hand picking and answering questions that have been keeping readers up at night, although we'll likely steer clear of those last two and keep it more tech oriented.




Whip it Good

Question: Pinkbike user wreckitsteve asked this question in the Freeride and Slopestyle forum: Is whipping your bike a bad thing? I meant, I do whip a lot, and land mostly on flat, with no transition because the nearest track available with big jumps doesn't have a transition landing (the builder does make some but it was way too short while I landed farther). And also I ride a lot of urban too. Today I started to feel that my bike is heavy - it can't go fast as my other bike. It seems like the rear wheel is a little bit not aligned with the frame - I've change hubs and it was no different. Is it possible that it is the chainstay that is bent? Is it because I do too much whip? Or is it because I do whip onto a flat landing?

bigquotesYou make it sound like whip is some kind of elicit drug, something sold in dark alleys by shady characters in trench coats, but I guess the feeling of getting your bike sideways is pretty addicting. It's not entirely clear whether you're talking about a tail whip, where the bike revolves 360 degrees underneath you, or a 'regular' whip, which means getting the bike as close to a 90 degree angle above the trail before straightening out for landing. It's the straightening out part that's key - landing sideways puts extra stress on your wheels and frame, and could certainly cause a bent chainstay. The same goes for flat landings - the forces generated by landing a trick to flat are much greater than if you land on a smooth transition. Just because you can overshoot a jump doesn't mean you should - aim for that transition, and your wrists and bike will thank you.

As for your potentially bent frame, I'd start by examining it closely for any cracks, bulges, or sections where the paint is discolored or flaking off. Spin the wheels - do they rotate freely, without any major wobbles? How about your spokes? Do they feel evenly tensioned? Are there any creaking or popping sounds when you pedal? You may want to swing by your local bike shop to have them take a look as well, but whatever you do try to avoid telling them you were "just riding along." If everything checks out, whip away to your heart's content, but try to refrain from those hucks to flat, unless you have a wad of cash lying around to replace the parts you're sure to break.
- Mike Kazimer

Nicholi Rogatkin knows how to tailwhip everything just like Martin Soderstrom did back in the previous editions. As the Giant is absent this year at V.A.K. the young guns go for the win.
This is a tailwhip.
Finn Isles 1st place at the Official Whip off Worlds Crankworx 2014 Whistler British Columbia Canada
And this is a whip.





Can Carbon Rims Be Too Stiff?

Question: Gooded asks in the All Mountain, Enduro & Cross-Country forum: I recently purchased a set of carbon rims from Light Bicycle for my 2014 Enduro 29 (carbon). The stock wheels (24mm internal) allowed the rear tire to roll a little at around 27 psi. (I'm about 160 lbs with gear). The stock wheels also felt a little flexy (mostly noticeable when traversing at low speeds, or when cornering at high speeds). My new wheels are 32mm internal-width, 32 hole, 3 cross. They felt much stiffer as soon as I started riding them. And, because they are wider, I was able to run much lower pressures without rolling my tires. I went from 25/28 psi to 18/22 psi. Because of this stiffness, and pressure, I'm able to corner faster in berms.

There does seem to be a HUGE tradeoff though. In the rough stuff, the bike seems to bounce around a lot more. I haven't adjusted my suspension based on the wheels yet, so that might help, but I don't really think that's it. The way I described the feeling to one of my buddies was, "imagine you're in some rough terrain and your front tire gets light, so it's barely touching the ground. Now you bump the edge of a rock with your front tire. It feels like my stock wheels would have deflected sideways and the impact would not have affected my trajectory much. It feels like my new carbon wheels are so stiff, that when they bump that same rock, the entire front end of the bike deflects to the side."

I had hoped that the stiffer wheels would help with the "point and shoot" method of tackling rock gardens. Each time I have purchased a stiffer bike or fork, I have been impressed with how much it helped me with technical sections of trail. I was able to put the bike where I wanted. This is the first time where added stiffness seems to be a disadvantage. My new rims are wider and stiffer. I'm glad they're wide, but I'm not sure "super" stiff rims are an advantage. I'm wondering what other riders have experienced. Do you love your carbon rims in every aspect, or do you agree, there is a definite tradeoff? Is there a way to counter this stiffness (spoke tension, spoke count, lacing pattern, etc)? Thank you.



bigquotesFirst, you are correct that the change in the ride quality can be noticed by many riders who switch to a stiff carbon rims after riding old wheels that have been beaten into submission, or new ones that are lighter weight or more flexible. Specialized aluminum and carbon rims tend to be very compliant (ever hear the "bawaanng" sound that comes from the change in spoke tension when you smack a Roval wheel on a rock?), so the switch to the wider Light Bicycle rims should not have been a subtle change in feel. That said, the effects of stiffer wheels are not as dramatic as pro riders and the press often insist, especially when using trail-bike-width tires at lower pressures and on a longer-travel chassis like the Enduro 29.

My guess is that some of the firmness you are referring to is the added sidewall support that the wider rims give, which may require a reduction in low-speed compression on both ends of your suspension. I have experienced that as well. Also, you should expect more feedback through the handlebar because stiffer wheels and tires that don't tuck add up to much less lateral deflection. Ten millimeter wider bars may be the solution.

I have also noticed that the width of the sidewalls can exceed that of the edging blocks of some tires when they are mounted to wider rims. This can cause the tire to refuse to grip off-angle rocks and often to bounce laterally through rock gardens that the bike had previously held a tight line through. You may have to choose a different front tire that has more pronounced edging blocks up front to complete your conversion to 32mm-width rims. Also, you did not mention whether your tires were tubeless - they absolutely should be when paired with wide rims.

far as reducing spoke tension, I'd vote against that, because it dramatically reduces the lifespan of a wheel. Lighter gauge spokes at the correct tension would be a better solution. - RC


Roval Traverse Fattie SL review
Specialized moderates the stiffness of its 30mm-inner-width Roval Traverse Fattie SL carbon rims by building the wheel with light-gauge spokes.





Cracking Weekend

Question: Pinkbike user Pushnaka asked this question in the Downhill Forum: Hey there guys. Had a smashing week in Wales last week - literally. I snapped the rear chain stay on my 2010 Trek Session 8. I was wondering if anyone can get hold of one or if anyone has ever welded one back together. I've snapped it across both welds. I got in touch with my LBS and they rang Trek who said they cant get the part anymore. Sell outs. Anyone help me out I need to ride again!


bigquotesFirst things first, you should be thankful that the swingarm failure wasn't catastrophic! Trawling the Pinkbike BuySell might be your only hope to find a spare part, or perhaps finding another complete Session frame to cut and shut the best parts together, and then have some spares left over for the future. Unfortunately, you are out of Trek's three year warranty for the Session, so you will struggle to get any more help from them. Welding could be an option, but would need an expert alloy fabricator who can heat treat the swingarm afterwards. Something to consider is that aluminium fatigues over time and becomes more brittle and likely to fail. There are various opinions on how long an alloy frame should, could or would last, but the swingarm failure may have been the "Canary in the coal mine" - a sign that the frame's lifespan has come to an end. If a lightweight aluminum race bike like the Session has suffered a full five years of downhill abuse from new, it's likely ready for retirement. - Paul Aston

Welding.
Welding can sometimes help prolong a frame's lifespan, but more often than not it's time for a replacement.



Have some unresolved tech questions? Jump in the Pinkbike Forum and we'll look to answer it for next time.


132 Comments

  • 81 3
 is it normal to send a broken alloy 2012 demo 8 back and get a 2013 carbon TLD S-Works demo back? I mean it was a broken chainstay and i got sent the whole new frame with shock and all.. Its not like im going to return it but isnt that a little crazy? My dealer said they just didn't have the same alloy frame in my size back at the distributor so they had no choice .
  • 8 0
 Lucky!! Probably they ran out of spare frames for the demo and that was the last one.
  • 19 0
 My friend just cracked his demo frame and is getting it replaced with a carbon one. Same thing i guess
  • 23 1
 I've heard some crazy specialized warranty stories like this before. My buddy snapped the CCDB shock on his demo 8 with no frame damage, but they sent him a brand new frame with the new Ohlins shock.
  • 39 1
 God Bless the Big S Y'all!! Haha
  • 5 2
 that was in stock, be happy
  • 28 0
 I work at a bike shop that sells specialized and believe me when I say they have one of the best warranties in the game. One of the few bike brands I know of that gives a life time warranty on their frames and stands by it. Just keep your receipt folks!!!
  • 17 5
 Specialized is a beautiful group of people to work with and they have always gone the extra mile with warranty and customer service. We're very happy to be a Specialized dealer because they truly stand behind their products and support local bike shops. Both the customer and the dealer benefit from the efficient customer service that Specialized offers. That's what you recieve when you walk into your local bike shop instead of buying online.
  • 9 0
 That's what happens mate. I cracked a 2013 carbon demo 1 and they replaced it with a 2014 demo 8 sworks (ohlins shock and all) for free
  • 11 1
 I have 3 buddies who have cracked old 26" carbon Nomads and are now getting shiny new 650B frames. There's something to be said for going with a company that has great warranty.
  • 42 1
 Man, you guys are making me want to crack my frame!
  • 2 1
 Keep in mind that life time on the frame should read front triangle.
From their warranty page

"Chain stays and seat stays on full suspension bicycles sold after 2008 will be covered under this
limited warranty for five (5) years from the date of the original purchase."
  • 9 0
 Cracked my 2008 Giant GloryDH between the head tube/downtube. Life time warranty they said... still riding the cracked frame...
  • 24 0
 Yeah Specialized has some big corporation issues that everybody hates. But idk how people people can hate so much on a company that has been making top quality bikes as long as anybody else, for decent prices, and that values their customers so greatly like this. That is what is important to me when buying a bike.
  • 5 0
 I've heard several stories of people breaking their old specialized frames and getting new really nice ones like carbon, but how the heck did you break your demo?
  • 4 0
 Had the same experience with Santa Cruz, broke the rear subframe of my alloy 2012 Blur LT and they replaced the whole frame with a 2013 carbon LTc. May have had a bit to do with the move away from 26".
  • 2 0
 I've had the same thing except with a Fox shock. Went to get it serviced, and they found a leak in the air canister. So they sent me a brand new Kashima coated CTD shock (WAY more expensive than the one I had) for the price of the service. It wasn't even warrantied!
  • 5 7
 I know a guy who has cracked 4 carbon demos
  • 14 2
 im cracking mine now
  • 6 4
 Shame they didn't have any aluminium frames left and sent you a carbon one.....I would have been gutted. ;-)
  • 2 0
 220lb + rain and mud+kid got in the way + hit the double anyway after braking a bit = (case +over the bars) /2
  • 6 0
 you know what? actually im pretty sure it was the go pro
on the helmet ..
  • 2 0
 Yeah it was totally the go pro good that uci banned them
  • 3 0
 Plan for the weekend: cracking my 2011 demo 8 frame
  • 2 0
 @Frilko don´t forget the go pro Wink
  • 1 0
 @AMGoran don't forget to send me some flowers to the hospital Wink
  • 2 0
 Giant replaced my 2007 glory with the 2014 frame this winter . Cracked mine in the same spot. If you have your bill of sale and go back to the shop who sold it to you there should be no problems. Yes it took a few months to get my new frame but they were also just releasing the 27.5 glory
  • 2 1
 Maeeee que nivel encontrarse ticos en Pinkbike jajaja
  • 1 0
 Luckiest dude on earth.
  • 67 1
 Sounds like the whip guy needs to build his own jumps.
  • 30 4
 Do you even whip bro?
  • 7 50
flag mountaincross (Jun 30, 2015 at 13:02) (Below Threshold)
 Are you black and do you whip in the park? You do! Didn't mean nothin' by it. have a nice day!
  • 11 22
flag mountaincross (Jun 30, 2015 at 14:23) (Below Threshold)
 Here is the comic bit I was referring to...https://www.youtube.com/watch?v=OloLS5kTrVs. I don't think it is meant to offend anyone's racial sensibilities. But if it does, I do humbly apologize...perhaps this form of comedy shouldn't be promoted.

What I should have said was, "Are you riding a Session and do you whip in the park? You do! Didn't mean nothin' by it. have a nice day!
  • 3 0
 Ah shit @mountaincross -1 for making me watch that link...
  • 24 3
 I've always gone with this rule of thumb...

When a good time turns around
You must whip it
You will never live it down
Unless you whip it
No one gets away
Until they whip it

Now whip it
Into shape
Shape it up
Get straight
Go forward
Move ahead
Try to detect it
It's not too late
To whip it
Whip it good

Wink
  • 6 0
 I used to roller skate to Devo
  • 14 0
 RC, thank you for posting my question. As a reply to a few of your questions/comments;
- I am running tubeless.
- When I made the switch to the 32mm internal rims, I also went from a 2.5 Minion DHF 3C EXO, to a 2.3 with all the same specs. Your comment about the tire possibly being too narrow for the rim really seems to describe the feeling that I'm getting through my front wheel. I think I'll try switching back to the 2.5 and see if it helps. (rear tire remained the same 2.3 HR2 EXO)
- I've got a PIKE RC that I've always run full open, so I can't adjust reduce compression there, but I'm running a Double Barrel out back, so I'll try to reduce the compression and see if that helps.

Aside: I demo'd the 2016 stumpy last night, with the aluminum traverse Fatties. I think I prefer the ride of those wheels to the Light Bicycle hoops I just bought. I'm fairly confident there are some carbon hoops out there that would be great, but at 150 lbs, I think buying the absolute stiffest wheels that I could find, and lacing them up 32 hole was a bit of a mistake. They'll probably make their way to the buy/sell page shortly (gotta try your suggestions first). Thanks again.
  • 4 0
 I forgot to address another comment; I'm running DT Swiss Comp Spokes 14/15/14 gauge. At 130kgf. I used a Park Tool Tension meter to build up the wheelset.
  • 7 5
 I bought Light bicycle hookless 27mm internal and after a year on them I am selling them, solely because of too much stiffness. Spokes won't change much since most of deflection, thus experienced compliance comes from rim getting momentarily bent sideways and twist, which does not happen on carbon rim almost at all. Then wide rim profile putting your tyre sidewalls more straight vertically doesn't help either. It does a great job of keeping your tyre from rolling off at low pressures but it adds to stiffness. I have just ordered DT Swiss EX471. 50g weight penalty per rim is nothing, and I want smoothness back, I am tired of the stiffness and the noise when hitting smallest roots.
  • 3 0
 Waki, thank you for the input. I actually didn't even save any weight with my new hoops. They are 500g per hoop. Again, they were the stiffest hoops I could find. Light Bicycle part number RM29C14 with the Downhill Layup for extra durability.
  • 6 4
 I am personally fine with carbon hoops on 29ers since side forces are increased and weight savings are more necessary, because weight lies at a larger diameter. I used to ride with 700g rims on 26er and they felt nowhere as slow as 620 ones on a 29er. Then it seems like a great idea for an XC racing bike, since sub 400g 29" alu rims are all feeling like cheese, they are worthless as soon as you lean the bike more than 5 degrees.

Cheers!
  • 3 0
 I've considered some of those rims. Thanks for your thoughts.
  • 4 0
 the EX 471 is also the 500g rim used on Gwin's tireless run… and chainless run
  • 10 2
 Haha, honestly, that's the second reason why I bought them over 420g Ryde Tracer Enduro. First of all they come at decent price for 25mm internal width. They are cheaper in Europe than ZTR Flow EX. Then they must be a good quality product since they hold up under him! So Rydes lost because I am sceptical of their weight, they are expensive, and I had a proof from Aaron. Then I considered DS25 from Superstar for half of the price of DTs but... I don't like lacing wheels...

Aaron Gwin made me buy ex471 rim, give him a raise DT! Big Grin
  • 9 0
 @gooded and @WAKIdesigns at 75kg weight I also found the carbon rims I had for non-destructive testing too stiff. I went back to alloy. Just adding another data point
  • 3 4
 Wait, Gwin wasn't on carbon rims?!
  • 6 0
 I have a set of EX 471's on my Nomad. I've had ENVE and SRAM Roam carbon wheels in the past and these are better for me in almost every way. Smoother, crazy durable and $100 per hoop. I'm a fan.
  • 1 1
 You can change the damping and probably should since you're at the limit of adjustment - unfortunately, this means taking the shock apart and modifying the shim stack. Not a horrible job and a good excuse to service your fork.
  • 6 7
 FYI do not buy Light bicycle Rims! If you weigh more than 200lbs forget about it. My buddy and I went through 2 pairs each and every time we had to pay 50-60$ to get them to warranty them. On the second set they would warranty them and stopped returning my emails. Not to mention I had to pay a shop to rebuild them twice. So all that "savings" from buying them resulted in more than what I would have spent from an American company with a real warranty and service. So to light bicycle I say eat a bag of dicks!
  • 2 0
 @skelldify - Nope. Gwin was running the DT EX471 aluminum last year without a tire and this year without a chain at Leogang. Look for photos. Regarding the carbon wheels, I experienced the same phenomenon on a Warden I demo'd three days last week. The I9 carbon wheels bounced around in the rock gardens far more readily than the DT Swiss EX 1750s I've been running on my Endorphin. Same tire. Lower pressure in the Minion on the carbon wheel.
  • 1 0
 @gooded - I run the same light bicycle rims but with 28 spokes. Mine are have tensioned to just over 100kg/f and I couldn't be happier.
At 130kg/f you are at the stiffer end of the recommended range.

From Light bicycle,

"The maximum spoke&nipples tension is 180kgf .

A. Tension for "transportation riders" (Comfortability)
80-90kgf are ideal for regular transporation riders or exercise on a regular basis.

B. Tension for "enthusiast riders" (Balance)
100-110kgf are good for people with enjoyful and training purpose.

C. Tension for "professional riders" (Performance)
120-130kgf are charged for riders who are expertized in riding or competition.

the recommendation spoke tension is less than 130kgf"
  • 5 2
 sheldonbrown.com/rinard/wheel/index.htm

According to this article, the Spoke tension is virtually irrelevant for vertical displacement of the rim, as for a rider of the same weight, the difference between lowest tension and highest tensions is measured in tenths of a millimeter. So there is a common misunderstanding that rim conforms to the terrain by flattening slightly, increasing contact patch for the tyre, thus offering more grip. In case of tenths of a millimeter, such thing cannot be true.

Rim flexes in all directions, it temporarily bends to the sides and twists across it's section. Such mechanics are virtually non-existent in case of a carbon rim.

So retension your spokes all you like, even in lightest instances, carbon rim will still be stiffer than the stiffest aluminium rim out there. Sounds splendid for racers on 29ers, not for amateurs on 26 and 650B. It's all in our heads, my head likes comfort of aluminium rims
  • 2 0
 I think you need to look at your suspension tuning... It's not your wheels that are bouncing you all around in rock gardens. Your flexy wheels before might have been shadowing an underlying problem of a subpar suspension. By subpar suspension I mean anything stock Fox etc... I had the same problem building up a set of LB carbon wheels on my 29er, but I have built 3 sets of LB wheels so far and I'll never go back to a flexy aluminum rim. Once I upgraded my bike's suspension after the noticeable difference in wheel stiffness to a properly tuned pike and cane creek inline with proper tune it was a whole new bike and I got ALOT faster.... honestly, this is my personal experience and NO ONE, I have suggested a suspension upgrade has said it wasn't worth the price of admission...
  • 6 4
 Suspension tuning - really? Yea I'll set my sag to 30% front, 40% rear and I will be finaly able to enjoy my rims - on FB post and on kitchen scale... I don't even token bro, I have a coil in the front and then I bare a Push sticker on my shock as a trophy and a sign of my upper middle-class social status...
  • 3 1
 Ignore the advice to switch spokes. Thinner spokes won't change the wheel's feel. Put simply, spokes don't stretch no matter the gauge. They bend but that really doesn't affect wheel stiffness. Seriously, thinner spokes don't stretch more because spokes don't stretch. This is a common misunderstanding even among experienced wheel builders.
  • 2 1
 @WAKIdesigns a properly tuned shock for your weight and suspension platform by a suspension expert can do amazing things. Setting improper sag is not a "properly tuned suspension". Instead of just blaming rock garden hop on stiff rims, try a tunable shock like a cane creek double barrel, or inline, do multiple runs of the same track and do some shock tuning.
  • 2 0
 I bought mine for the same reason, hope hubs for easier future proofing, they are outstanding rims
  • 2 1
 Ex 471's that is
  • 2 2
 @manchavegas I have a Push tuned Factory Float CTD for my personal preference and bike... please... I had Crossmax STs before I bought LB on Hopes, and fast feeling bike got as rough as my Float CTD on lock out before Pushing. Then I was doing bracketing on my 36 Van RC2 and found the sweet spot, which is nowhere close to being plush. I am after stability. There is nothing wrong with my setup apart from the fact that those rims made my bike feel like it has half of the travel. Off course it doesn't but it feels like crap and hole sht gets magnified by running them tubeless. I went for LB because they were wide and I hated narrow STs for how tyre was wobblying around the rim, I fkd 2 tyres on it by landing sideways.
  • 4 0
 Are you sure you just didn't forget to wear your Chamois that day?
  • 2 0
 I always wear bibs with a nice soft diaper and smudge my bum with chamois cream. If I don't then things escalate quickly, having in mind that I use my dropper post at least 1-3 times per minute.
  • 11 0
 "you are out of Trek's three year warranty for the Session, so you will struggle to get any more help from them".

All I need to know is right there. Future purchase decisions taken.
  • 1 0
 My 2009 Specialized Stumpjumper FSR Comp 26er that I bought new at my LBS broke at the rear triangle at the seat to chainstay bridge. Not at the weld mind you. Just noticed it was cracked right in half one day to the next. Checked with several LBSs and they said I'm out of luck as Specialized will only warranty the front triangle for life (?), and rear triangle for 5 years. They (the LBS) did offer to give me up to a 30% discount on a new bike. Still, that means like 3-4K out of pocket for the one I want, thus I'm stuck with a broken frame and a bike-build worth of parts. And it's damn near impossible to find old 26er frames in good shape for little coin that I could build up with those now parts based on obsolete standards (straight steerer etc.)

Thanks Specialized.
  • 16 6
 So in a couple years I'm guessing we'll get 27.5- with narrow, flexy aluminum rims for added compliance, weight and speed. It's gonna be a real "game changer". The innovation train keeps rolling!
  • 17 0
 wait, is innovation rolling or Trolling?
  • 17 4
 Carbon rims are too stiff. That's what you were feeling.
  • 38 3
 Carbon rims are too expensive. That's what you were feeling.
  • 1 1
 Yep I reckon that's about it teamrobot. I've had the same experiences when going from a normal wheelset to Crossmax Sx. They have those huge hollow aluminum spokes that just don't have enough give in them.
  • 7 9
 Carbon rims fail just like alu ones, guess which ones are cheaper to replace darling... or you are just tired of truing alu rims? So sad indeed. I hoped you like turning nipples.
  • 4 3
 Actually carbon rims fail very differently than aluminum ones. One gets a wiggle and the other explodes or gets a Crack that stops you from riding for fear of it exploding.
  • 17 4
 Yes carbon rims explode and gluten makes your dk fly off
  • 4 0
 WAKI, my buddy's carbon rim literally exploded at the shop just last week. The sidewall of the rim failed catastrophically while the bike was on the repair stand, not even JRA. AL bends, carbon breaks.
  • 10 0
 The marketing force, that's what you were feeling.
  • 8 1
 I love turning nipples...
  • 3 1
 Prostate massage is where it's at.
  • 1 0
 Generic carbon rims with no engineering behind them are too stiff. There's a reason good carbon rims are expensive and LB's are cheap. In my experience, if you have cheap, super stiff carbon rims you need suspension with good small bump compliance, which is usually expensive. So one way or another, you're stuck paying for performance.
  • 3 1
 Good suspension with good small bump compliance is just a tool, set it up right is another story. Most pros can't do it, they have mechanics for it. Some people should take a look at a Fox or RS truck at some spring factory tech camp in Spain or Italy, and get some perspective how setting up a shock looks like. Carbon rims are freaking harsh to ride on, even ENVEs and not everyone likes it while many pretend they do. Cuz it's carbon... Stupid rumor has it that Syndicate runs their wheels 20% below recommended tension. So yea it is a fantastic idea to take out few clicks of LSC get more diving, just for the sake of running a carbon rim that is 50g lighter. Thumbs up and munch the genuine innovation baby!
  • 3 0
 Carbon rims are not significantly stiffer than aluminum in the vertical plane, they're stiffer laterally. Changing suspension setup would create more compliance vertically, but wouldn't really touch lateral deflection. Remember when Fox redesigned the 40's lowers to incorporate additional "compliance" aka flex that their athletes requested? You want some degree of lateral deflection. Stiffer is not automatically better.
  • 3 1
 1.I rode a shiver SC on a pumptrack this weekend and I was able to pump berms like on any other fork
2. Shimano chief execuctive called me and wanted to sponsor me if I put #Irideshimano hashtag under every comment
3.Arnold Schwarzenegger got himself a multi-flex zone bionic penis to stimulate his prostate

Which of the above stories sound least likely to be true, to an average New Age Gravity rider?
  • 2 0
 TEAM-ROBOT, thank you, you helped to reiterate the real issue I am having. I'm happy with the vertical travel on my bike. I'm certainly feeling more of the terrain, vertically, but that's fine. I'm not looking for a plush, comfortable ride.....I'm looking for speed. The issue I noticed is that the wheels are bouncing off of rocks LATERALLY. Before these wheels, I think my wheels must have been deflecting AROUND the rocks, now they are deflecting the entire bike OFF of the rocks (sideways). I'm going to take RC's suggestion, and go back to running my 2.5 up front (instead of the 2.3 I installed when I swapped wheels). If that doesn't work, the wheels are probably going on buy/sell. I will probably make a few adjustments to my suspension, but I've already spent a lot of time getting my suspension ACED. I used bracketing to adjust the rebound on the Pike, and I followed Cane Creeks recommended procedure for my Double Barrel.

I may experiment with running an aluminum rim out front (where I never experienced any issues with stiffness), and keep the carbon hoop out back, where the bike felt a little squirmy in berms and pumping turns.
  • 2 0
 I didn't notice any problems with carbon rims until I went back to aluminum. When I made the switch back it was mind blowing. Aluminum rims track so much better. Night and day.
  • 1 0
 Weren't you on Enve's anyway ROBOT? Despite their "made in 'Murica" pedigree, I wouldn't put them in the well engineered category. Reynolds, Derby, and Nox composite rims feel a lot more like aluminum rims rather than MOAR STIFFNESS CARBONZ!!! rims that more roadie-oriented companies have.
  • 2 0
 So @tsheep- "well engineered" carbon rims should feel "more like aluminum?" If that's the case, then what's the argument for carbon? $900 per rim to save ~50 grams?
  • 3 0
 Post-purchase rationalization is a hell of a monster
  • 1 0
 @TEAM-ROBOT what aluminum rims do you run?
  • 1 0
 Flow EX's on the downhill and 160mm bike, WTB KOM's on the 29er. 440 grams for an aluminum rim that costs $95? Makes carbon hard to justify.
  • 1 1
 Add Superstar tactic i23 26x400g at 40£ and DS25 i25 26x490 at 30£ and carbon explodes under the market pressure
  • 1 0
 @TEAM-ROBOT Yeah, basically they should feel like good, stiff, bombproof aluminum rims- but more along the lines of like a Mavic 823 rather than a Flow or KOM (not that those are bad rims). So if we're shooting for the feel of an 823 (655 g, $85), and comparing it to a Nox Farlow (420 g, $480), then you're paying about and extra $395 to shave 235 g per wheel. Maybe a bit steep, but not anywhere near as bad as it could be.
  • 2 0
 Oh well, I think ENVE 60 feels like sun rims double wide, it is stronger though and on top of that you save more than a pound per rim. Win-win indeed. I would still not ride ENVE or any other carbon rim even if they gave me one for posting one hashtag per month. Oh I remember the good old times on Alexrims Supra V... is feeling sentimental
  • 6 0
 After researching a lot before choosing my stand flow ex rims (still a decent width for 2.3-2.4 tires) I found multiple things about carbon being possibly too stiff. This interview had a good amount of detail even going into braking traction, dirtmountainbike.com/features/carbon-mtb-wheels-do-you-need-them.html#fFfUYtA2CMYwiEPp.97

Also one review of the nomad with the enve the riders commented on harshness of the bike until they changed the wheels (a UK review I believe).
  • 1 0
 I was just about to post this same video! Great info in it.
  • 1 0
 very interesting
  • 6 1
 The problem with the "Too stiff carbon rims" might be caused by a too fast rebounding fork. I would try more rebound damping. Once I noticed the same behaviour when I testet a DC-fork (88Cool instead of a MZ 55 RC3. The added stiffness seems to require a much better setup to prevent any unwanted behaviour of your suspension...
  • 1 1
 I run my rebound almost completely open (front and rear). I have just enough out back to keep the bike from bucking when I leave the lip of a jump. I'll experiment with this too. Thank you.
  • 3 0
 Any change in wheels or tires should always include a change in suspension settings as well, especially if your preferred settings are on either extreme of the suspension's adjustment range. Write down the current settings and take notes as you make changes.
  • 7 1
 with as many bikes out there that look like a session, @Pushnaka should be able to find parts out there somewhere.
  • 3 0
 Riding 40 mm Nexties and to not get stuck on the "too stiff train" I opted for 28 spokes front and rear. They re still lively, but hold lines like no other wheels and corners unimaginably well.
  • 1 0
 How much do you weigh? Also, what spokes did you build up with?I was stuck in the "stiffer is always better" mindset in shopping around for my new carbon build. However, the more I read, i'm starting to realize that's not always ideal.

I'm right around 195-200lb right now and have just purchased a set of 28H Torch . I originally wanted 32H but I couldn't resist the deal on these. Now I'm thinking that it might actually mitigate this overly-stiff issue. I was even considering going with the heavier, DH build (if I go LB) to make sure its durable/stiff enough, but, again, starting to think this won't be an issue and should just stick to the normal, AM layup. FWIW, they'll be going on a Stumpy Carbon Evo 29 and I ride lots of rocky, root-filled trails and like to play/jump whenever possible. I'm new to all this so any opinions or input?
  • 2 0
 Do some carbon mtn wheels (ie Roval) have lower spoke count to help make them more compliant? I'm curious because I've considered purchasing Light Bicycle rims to mate with my current DT Swiss hubs from the Roval Fattie wheels. Has anyone done this upgrade? Feedback on how it went?
  • 2 0
 I have both light bicycle 32 spoke wheels and roval fattie carbons 28/24.
The LB wheelset is noticably stiffer, and the rovals rims are wider and burlier - its all down to the spokes when it comes to equally good carbon makeups
  • 2 0
 Good to hear.

I just bought a set of alu traverse fatty wheels versus light bicycle carbons. I wanted something with a warranty incase something went wrong. When i asked the lbs manager about the 24 spokes that were thin he said I'll be fine and if I'm not he'll take care of me.

I've only got 5 miles out of them due to a brake failing on my bike but in that 5 mi i rode a few laps of the dj track (its on my giant trance 27.5) and had some whips that landed crooked. They definately felt stiff and had more traction than my giant branded dt wheels (25mm internal) . They also roll much better.

So far so good, but if something goes wrong i know I've got the lbs and specialized warranty to back me up.
  • 4 1
 Oh well, when it comes to alu Sessions it is not a matter of five years, many cracked muuuch earlier. I saw myself 3 cracked frames at my friend's shop, all at the same place. Those stays are made of a sessioned coke can.
  • 1 0
 My stumpy also broke at the stays. More precisely, the chainstay to seatstay bridge, if that's what you call it.
  • 13 10
 What's the best way for me to fit 29" wheels in my 26" frame? Hacksaw? Grinder?

How can I get sponsored? What tire pressure does Aaron Gwin run?

What's the best way to make my own winter spikes? Screws through the tire?
  • 15 0
 Sawzall. Go faster. More than you. Yes.
  • 4 0
 Tape some bamboo onto the rear chain stay to increase length. Works a treat. Strong but with a good flex for extra travel.
  • 11 0
 Aaron Gwin runs 20 psi in the front, with 0 psi in the back.
  • 3 0
 Heat, my friend, and lots of it. Make that frame hot and you can bend that thing and just force those 29's in there. Sponsorship? Buy a couple stickers and slap it on your bike/helmet/whatever, you'll look like your sponsored. Winter spikes? Easy, remove the tires and start chiseling at the rims - not too much, mind you - until you get a nice ragged edge.
  • 9 8
 Reducing spoke tension does not reduce the wheel stiffness anyway. It is a common misconception that this has any effect on the wheel stiffness - think of it lime the preload on a coil shock. Increasing the preload does not change the stiffness, it just changes the sag point. Spoked bicycle wheels ALWAYS have to stay in the linear elastic area - decrease tension and they will unload under stress (resulting in broken nipples), increase tension too much and the spokes will break (or the flange of the hub) under load.
  • 6 5
 So wheels will always as stiff as they will be ,regardless of spokes,spoke tension or number of spokes I know this is Pink Bike,but we're not that dumb
  • 2 0
 There is no way this is true, I just built up a set of wheels to proper tension and on my first ride they were noodles, the tire was rubbing my frame at points. Then I used a different tensionometer because the spokes felt under tensioned and I realized that the original meter was inaccurate. As soon as I got on my bike I could immediately tell the differance. And I only tightened my spokes about 15kgf
  • 5 0
 This is a weird concept and one I have read on here a few times. I have done some free body diagrams to work this out and yes, wheel stiffness in the vertical is not dependant on spoke tension, assuming the tension is not so low they are loose or so high they are at their limit of failure.

Basically, if spokes are very tight, the load stopping the axle moving to the ground is held by the spokes facing upwards but are actually carrying the additional force of the spokes facing down, hence, the additional force holding the axle up from the high spoke tension is countered by the additional spoke tension pulling down. This is true of the lateral forces.

The problem is that our experience is different and high spoke tension tends to allow a little more vibration through from the trail and this implies total stiffness is higher. This would imply spoke tension is an issue with wheel stiffness.

Does anyone give enough of a shit to elaborate on this? Spring preload is not a good example although it is semi valid because the spring in a shock does not make up a set of coupled forces.
  • 2 1
 A spoke is nothing else than a spring! Your observation of it feeling more stiff may be correct, but the total stiffness does NOT change - what more tension does is that it increases the friction at then crossings, making the wheel feel a bit harsh. But the Elastic Modulus - which is responsible for the stiffness - is linear until the spoke starts to elongate - where it starts to decrease.

If you were to release spoke tension to the point where stiffness changes, it would be a very noisy wheel to ride.

@scary1: nope, spokes and number of spokes are the only real influence on stiffness... much more so than the rim itself.
  • 1 0
 Both frames and rims need a certain amount of compliance, whatever the material. Imagine if they were both as stiff as possible and you pile into a rock garden at mach 5 - its gonna be a rough ride for sure, at least for us mere mortals. Lets also keep in mind the benefit of a certain amount of compliance under heavy braking.
  • 2 2
 RC has is right, since the tires are running at much lower pressure you have to retune the suspension. The tires are now doing some of the job the suspension was doing. Reducing the LSC and HSC would, in effect, allow the suspension to take back some of the suspension work the tires will naturally do when you lower the pressure.
  • 1 0
 Pretty sure I was talking to the guy who snapped his session in Wales last week, if its the same guy... That split was nasty, mainly because it's such a hard thing to fix, praying it never happens me haha
  • 1 0
 those roval fatties are damn nice for the price. i got the alum ones and im 230 pds with gear. ive jumped them, crashed them still straight a year in. fast as well. damn you specialized!
  • 4 1
 You can find my trying to whip While I wear new balance kicks
  • 1 0
 So is that "bawaanng" sound with Roval's normal then?? I have the carbon ones and it makes this sound all the time. A bit unnerving.
  • 1 0
 Wait, do i whip it before or after i hear the bawaang sound? I don't want to crack anything. Pretty sure my old JUNK is out of warranty.
  • 1 0
 Pinkbike, you need a t-shirt in your store that says "Is it because I do too much whip?" on it. I would totally buy that t-shirt.
  • 2 1
 I actually prefer the stiffer wheels because I'm heavy and like 29rs.
  • 2 1
 Me too. I went from enve 26am with 32 bladed spokes to OEM stans rapid 29er (also 32 spokes) and I am dying to get these "too stiff" LB wide carbon rims with the DH layup!

My bike climbs like a dream but often gets pushed off line through medium rocks and small roots. Something I didn't miss from my mountain bikes in the 90's. I'm hoping the 38mm carbon rims will offset all the compromises I've made for easier climbing.
  • 1 0
 I just cracked my 2009 SX and still have sale slip.should I send it?
  • 2 0
 Yes.
  • 1 0
 Even if there is no good reason to expect a warranty replacement, I always make a phone call, bike shop visit, or send an email, because you never know when it will pay off.
  • 2 1
 Nowadays you can even whip a carbon 29'er on carbon wheels. Only what for?
  • 1 0
 I can whip anything, because its fucking easy.
  • 1 0
 what are your thought on chenves (chinese enve wheel for cheap)
  • 1 4
 ENVE M70!!!!!!
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