Ask Pinkbike - Correct Spring Rate for My BoXXer Fork, Chain Guide or Not, Beginner's Essential DH Kit

Sep 23, 2014 at 1:09
Sep 23, 2014
by Pinkbike Staff  
 
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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.



Downhill Fork Sag

Question: Pinkbike user maljay asked this question in the Downhill Forum: I'm looking for an opinion on how stiff to run the RockShox BoXXer on the front of my downhill bike, a Specialized Demo 8. I think that it might have felt a little soft with the medium spring in it, but the shop that I had service the fork stiffened it up quite a bit. The fork has barely 20% sag now, and I didn't like it at first because I was used to the previous setting, but now I'm more used to how it feels and I like it a lot. I've just taken it to a different bike shop and they've said that the medium spring is too stiff for me (I weight 150lb) and installed a soft spring. Now the fork feels really soft, but my references are all screwed up. I feel like I'm really leaning on the front now and I'm a bit off balance in the turns. I know there's no right or wrong, but how stiff should someone run their downhill fork?


bigquotesYou're correct when you say that there's no right or wrong answer when it comes to suspension setup. Assuming that you're not way off in left field, there is certainly a range that you want to be in. That said, I see a hell of a lot of people out in left field when it comes to fork setup, with many running a spring rate so soft that the fork clangs off the bottom out bumper at the mere hint of an impact. It's one thing when the too-soft fork has four or five inches of travel, but it's a whole other ball of wax when said badly setup fork has eight inches of stroke. The issue is that when a downhill fork is too soft it ends up running far too deep into its travel, which in turn changes the bike's head angle drastically, something that has a massive effect on its handling. Just picture yourself braking hard into a corner, especially one on a steep section of the trail, and the fork going from sitting maybe a few inches into its stroke to being nearly bottomed out. The result is a much steeper head angle that will have your Demo 8 handling like cross-country bike when you want the exact opposite, which is what you're feeling when you say that you are a "bit off balance in the turns."

My opinion is that while aiming for a definite sag figure for a bike's rear suspension makes a lot of sense, doing the same up front doesn't, especially when talking about downhill forks. Some riders might need to run crazy stiff front ends if they're chargers (some World Cup pro's forks barely sag under their weight), ride steep terrain, or just like stiffly sprung bike. A stiff fork setup can lead to front ends that push and wash out on flatter trails, though, so it doesn't work for everyone. Forget about trying to run a specific amount of sag, and instead go by feel. If you're feeling weird in the corners and like your weight is too far forward, drop that medium spring back in and ride the same trails to see the difference. You weighing 150lb doesn't automatically mean that you should go with the soft spring, so don't believe anyone that tells you that. And remember that while your suspension's first job is to absorb the terrain and keep your wheels on the ground, it's second is to preserve your bike's geometry and handling - a bike that handles consistently is a bike that you can trust and ride quickly.
- Mike Levy

Troy Brosnan

Troy Brosnan may be a little guy, but I can guarantee he's not running a soft spring in his BoXXer.



Chain Guide for my One-By Drivetrain?

Question: Miloherbie asks in reference to his new one-by ten drivetrain in the All-Mountain and Cross-Country Forum: Top guide – Do I need it? I'm seeing lots of PB photos of bikes with and without. I’m running an old Marin and ride local drops and jump tracks and lots of rocky tracks that can shake your fillings out.

bigquotesPopular convention and thousands of miles spent riding clutch-derailleur-equipped one-by drivetrains with narrow-wide chainrings here at PB says that you won't need an upper guide. If your chainline is correct (50 to 51 millimeters from the center of the seat tube to the centerline of the chainring teeth) you should experience similar results, which works out to one or three tossed chains - or none - per year of riding. I prefer not to because I don't like the rubbing sounds that guides so often make in the cross-over gears. Before you start celebrating about the money you are going to save on that upper guide, though, consider that almost every racer on the Enduro World Series runs a one-by drivetrain and, with a handful of exceptions, all run an upper guide. Evidently, EWS racers have either experienced many more derailments than PB test editors have - or perhaps the penalty for even one tossed chain during a race run is simply too great to risk. So, if you are a betting man, I'd suggest you give it a go sans guide - you may get lucky like we have been. If you race, or you tend to shout and throw things when sidelined by simple mechanicals, then I'd suggest that you play it safe. An upper guide is lightweight, simple to install, and cheap insurance - RC

Crankworx 2014 - Bikes of the EWS

Both SRAM and Shimano claim that the combined effectiveness of their clutch rear derailleurs and specially-profiled one-by chainrings virtually eliminate the possibility of dropping a chain. Shimano-sponsored Jared Graves runs a top guide on his one-by-eleven setup - and you would be hard pressed to find another EWS pro without a top guide or a front derailleur.





What to Wear Downhilling

Question: PB user crazy-high-21 asked this question in the Girl's Clubhouse forum: I want to try downhill for the first time, no problem to get the bike and all the safety stuff, but what clothes to wear?


bigquotesWhen I started downhilling, I wore my boyfriend's old Mohawk Gas Station baseball jersey and pair of North Face hiking shorts that were part of my work uniform. I may have looked like a train wreck, but the clothes did the job and my immediate addiction to the sport ensured I would purchase a suitable kit over the course of my first summer of downhill love.

If you are just trying out downhilling and you're not ready to splurge a bunch of cash on new gear, I would recommend you find clothes from your closet that are comfortable, moisture-wicking and breathable. A pair of knee length, loose fitting shorts, like hiking or skate shorts are a great start. Look for something with room around the knees to provide space for your pads to sit under and make sure you are be able to move around in them. Try and avoid anything that's too long in the crotch, as catching your shorts on your seat can result in trouble. You mentioned that you already had access to safety stuff, so I assume that you at least have the essential body armour: DH knee and elbow pads, and a good-fitting DH full-face helmet. If you haven't thought of it already, get your hands in a pair of full-finger MTB gloves. They may seem trivial, but gloves offer you better grip on the bars, and an extra layer of protection when you decide to sample the local soil.

After your first day on the big bike, when you are in love with downhilling, you'll want to invest in a proper kit. Your list should begin with your own full-face helmet, body armour, gloves and shoes. Try stuff on, make sure it fits and make sure it's comfortable. If your kit doesn't feel right at the store, riding isn't going to make it better. I like to wear knee and elbow pads made from soft viscoelastic material that hardens on impact, but a hard-shell option is great too. It never hurts to have more on than less when starting downhill, so you may want to consider full-length leg pads as well as an upper-body protection vest. Goggles are essential, and you should treat yourself to some DH-specific shoes - the soles alone will have you in awe of how much grip they offer on the pedals. Finally, Invest in a good pair of shorts and a jersey. Many companies have devoted time and resources into designing product specifically for women, so make sure you try these options on, as the fit will be far more suitable for a female figure than men's stuff ever will be. Clothes designed for mountain biking are cut to move with your body while you are on the bike, so take advantage of them and get yourself set up. You'll look like the biz and you'll appreciate the functionality too.
- Rachelle Frazer

All the Citizen 19 ladies at the BC NW Cup in Silverstar BC

Take note: these women have got their DH kits dialed.




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

  • + 22
 They forgot to mention, Jared is also running a bash guard. Which, IMO, is more important.
  • + 5
 True. I think it all depends on where you ride. Even on the Shore the number of close roll-overs is fast dwindling. I've been running a bashless 1x for about a year now and have only had one glancing hit on my NW chainring. But in different places a bash might make sense.
  • + 3
 Exactly. Jared is actually sponsored by e*thirteen for chainguides. For most of his races he runs a modified LG1r carbon backplate guide with the lower roller and the back part of the bashguard removed.
  • - 8
flag Ridonkulus (Sep 23, 2014 at 17:50) (Below Threshold)
 Bash gaurds shouldn't be run off the iscg tabs. Under impact they will snap off the frame. A better option would be a chainring tab mounted gaurd
  • + 2
 If you use a chainring bash guard there will be a chance that there may be pedal vibration or feedback. However that is just your preference if you choose to run Bash or Taco
  • + 2
 if you dont drop chains on a narrow wide you aren't riding hard enough.
  • + 2
 I'm on 1-10 and i drop chain like nobody else i have ever seen, so narrow wide rings work as well as a guide? And add for clothes, make sure the crotch off your shorts isn't too low! The saddle will catch it sometimes
  • - 2
 jlfskibikesail@ Cam Zink and Brandon Semenuk runs narrow wide for their slopestyle and Freeride bikes. Are they not riding hard enough?
  • + 4
 I have a 30 tooth Raceface NW ring on my AM bike. I have no guide, and no clutch on my derailleur. I've ridden the bike hard down some gnarly trails and done a few days in the Whistler bike park with it. I dropped the chain once and it was when I struck a pedal coming over a roll. Not sure how that made my chain pop off. Anyway, my point is you don't even need a clutch. The NW rings are amazing.
  • + 4
 On the other end, I have a 34 tooth Raceface NW ring on my hard tail XC bike and an X9 type two rear der and I dropped my chain a bunch when I first got it. I then shortened the chain by a few links and spaced my BB out to the non drive side and I haven't had any problems since. They're nice but it feels like Im cross chaining pretty hard when I go into the easiest gear. I feel like I will be wearing my chain out faster with this set up
  • + 3
 I have a Wolf Tooth 32 with an XO non-clutch derailleur on one bike and SRAM XO1 crank with a saint rear derailleur on the other and I've only experienced one dropped chain (neither with a chain guide). However, I have two friends and a cousin - all with similar setups and who all dropped their chains when taking an extra pedal stroke between jumps - and who all ended with a face full of dirt. So it would appear to me that it's a complete gamble.
  • + 2
 I have a 30T Raceface NW chainring, 42T OneUp sprocket and medium X9 Type 2 derailleur without a chain guide on a Banshee Rune V2 and didn't have problems with chain drops until I rode Whistler bike park. The chain would drop off the chain ring multiple times when riding down some well worn pot hole riddled trails in late August. Installing a MRP AMg chainguide eliminated the drops off the chain ring, but I started having problems with the chain dropping off the rear cluster.
  • + 1
 That's weird mtbken, I have my 30 tooth on my Rune V2 with an non-clutch x7 and never dropped it in Whistler. I rode all sorts of trails those days I rode the bike in the park.
  • + 2
 I must be doing something wrong then. I still get to drop my chain from time to time with a NSB NW chainring and saint m820 rear dérailleur.

I clean and lube my chain almost every ride, but have noticed that with a dirtier chain I drop the chain more often.
  • + 3
 Well it didn't quite work for me without clutch, the chain just dropped a few times on one of my rides. I went ahead immediately after that particular ride, bought a SLX with clutch and haven't had any issue even on some serious DH tracks, jumps or anything like that. I think it has a lot to do with suspension design, particularly more chain growth could mean more chain slack when the suspension is extending, giving the chain more of a chance to drop.
  • + 1
 @knightridersix04 What's the largest sprocket in your cluster? I'm planning to try a shorter chain next time since I don't need to use the large sprockets in the bike park.
  • + 1
 36 tooth. Eventually I'll be going for a 42 tooth oneup
  • + 2
 30T race face n/w with a one-up conversion (rad cage, 42 tooth ring) on an XT clutch on my chromag stylus with no chain drops to report. Like others have said, get your chain length right and forget about that drive train. There are almost no smooth trails around here so it's a pretty good testing ground.
  • + 1
 some people think they are fast. WC racers said they made mistakes and they are slow. it's all perspective.
  • + 1
 I've a 32T Homemade CNC NW + a rear CNC homemade 42T cog and the XT Shadow Plus SG... and the chain never dropped down in nearly 1 year!...No chainguide ... downhill, bikeparks, everything done...
  • + 2
 Funny, I had the same setup as you, 30t RF NW with no clutch derailleur and a sensible length chain, and it came to the point where I was getting at least one dropped chain per minute. Not joking. Although I was riding rockyish trails on a hardtail, a top mounted chainguide stopped my problem almost completely.
  • + 3
 Chain security heirarchy:

1) An actual full f*cking guide.
2) Clutched RD with top guide
3) no guide narrow wide
4) everything else
  • + 1
 @NotDannyHart when i put the XT shadow plus on "OFF" the chain drop down easly, when on "ON" (always) never drop down, not a single time from when i bought it
  • + 1
 @nongio if only they made clutch and Type 2 RDs for 9 speed
  • + 1
 It can work with SRAM 9spd shifter with shimano 10spd shifter on a 9 spd cassette. I still use it but notice the one up 10 speed set up works better. Better meshing between a 10spd chain and everything else.
  • + 2
 Yeah, I have 9 speed x7 shifter and a zee clutch derailleur on my DH bike and it shifts perfectly.
  • + 2
 Right on. Mines x9 spd shifting a zee clutch. Zero issues after nearly three seasons of mostly climbing.
  • + 4
 Regarding suspension setup, balance front to back is huge. Also, have the rear slightly slower than the front. I prefer a softer setup, and let the comp circuits do some of the work rather than a pure hard setup with minimal comp damping. Some of the new fork technologies allow for softer setup as the damping cartridge is doing more of the work. IE charger damper.
  • + 0
 well in all the forks you can compensate the stiffness with a bit of a extra damping but extra oil damping leads to a different filling then extra stiff springs and its not the same. I do have Avalanche cartridge where i can change shims and make it more stiff and less brake dive and i do have a Akira race springs where they are stiffer then the stock im running. The difference is huge with race springs forks performs awesome on the flatter trails and gives me more confidence to hit a big lines drops roots. But performs really bad when it concern very steep roots steep pads and sections where i must have a bit of a dive. So stiffer springs or more damping is the riders choice regarding the trail conditions and demands. Wink
  • + 1
 Ya it's definitely not a black and white situation. I think my point more stems from the fact suspension technology has evolved, so should our setup methods. I venture to guess the dampers are doing more of the work, and are providing more mid stroke support sooner, generally speaking. This is by design. My point is, we are getting plush AND supportive now, as avy customers should especially appreciate. With a charger cartridge, as in my previous example, I can get away with a softer setup and still get big hit performance. Nice!
  • + 3
 The Straitline silent guide is amazing.
Starting at 187 grams for a 34 tooth bash guard and chain retention system. With the clutch derailer and N/W ring , dropped chains don't exist.
Check em out if your looking.

Made from 7075 T6 it's 7 times stronger than lexan, almost twice as strong as 6061 T6 Aluminum.
  • + 2
 I wonder how's there no mention of compression settings when talking about suspension. I had a Boxxer RC, and at 150 pounds I could have either ridden a soft (yellow) spring, which dived in corners and steeps but handled rough terrain properly, or I could have ridden a red, that dived less, but still did, and handled roots and rocks worse.

Solved it with an R2C2 damper, which allows for much better damping setup. Before moving on to air, I stuck to the softer spring, using the damper to keep the fork higher in travel but still able to soak up impacts.
  • + 6
 I wonder how much sag the chick in the middle runs?
  • + 1
 I'm feeling a bit in between spring options for my totem too.
The one is so soft that I use massive travel already for relatively small bumps, even with the compression fully closed. With the next harder I feel a lot more confident, but it seems that I only use more than 2/3 of travel when I
  • + 1
 ...do Rampage style cliffs, which I certainly do not. Compression is fully open for this option.
Any advice?
  • + 1
 If your really desperate, try putting spacers between the top cap and spring, I did that in my ancient boXXers and it stiffened it up without any bad top-out. That's my ghetto method anyway.
  • + 3
 make sure your damper isnt underfilled
  • + 1
 Fork has been serviced in a shop a few rides ago.
  • + 1
 maybe try wight he softer spring, pull the lowers all the way up, undo the foot nuts and tap the shafts out, then do them back up. It should be like adding a tiny bit of air Or with the firm spring, take the spring out, compress all the way, tap shafts out and create a negative air pressure in the lowers, so it'll make the fork softer
  • + 2
 try running lower viscosity oil, worked on my boxxer. The compression knob also makes sense now, before that it was alway open.
  • + 5
 Oh not again! I have nothing to wear..
  • + 3
 Should I wear a fullface during spin class or just a half lid with goggles?
  • - 1
 I prefer a fireman's helmet for spin class. It will offer better protection if there is an earthquake and the ceiling tiles begin to fall.
  • + 1
 Returning serious now, my outfit problems are how to avoid dust shield covering a sweaty face and rubbing traces under knee pads.
  • + 1
 i just recently set up a one by nine with an mrp top guide. ive been looking at a blacksire stinger so i can backpedal. will a nw let me backpedal? do i need nw specific chain/cassette? im also running a shimano xt shortcage.
  • + 1
 Dont know the detail bout that, but i cant backpedal in the easy gear (7th to 10th cog). But in harder gear 1st to 6th i can backpedal easily. I use WT 32T with XTR long cage. Maybe its because my setup or just the natural habbit of the system.
  • + 1
 Mybad, i just got home and checked it. You cant backpedal in the biggest cog (in a clean cog and chain situation). Or maybe if it's dirty the amount of cog that can cause skipping chain increase.
  • + 1
 its wierd, on my dh bike i can whip the cranks around backwards as fast as i can and it wont bind up ever. this new build and i cant spin it once backward slowly without it binding up unless its in those gears right in line with the c-ring. only real difference between the two is the dh bike has a chaintensioner under the c-ring.
  • + 1
 Maybe the chain or the cassete or both are worn out a bit?
I cant backpedal either with my streched chain.
But who knows, im newbie to these 1X and just start to experiment with everything.
  • + 2
 I weigh 145ish. I have a medium (red) spring in my boxxers running about 20% sag. Feels pretty good usually, certainly wouldn't want to go softer. Would get a bit too wild in the steep techy stuff.
  • + 1
 goes hand in hand with one of the EWS bikes they got to ride at whistler, that had 40% rear sag. a rearward weight bias is more advantageous, the steeper the terrain, when you point the nose downhill. It's SOMEWHAT the opposite on the ups(if you've never experienced it, fighting to keep your front wheel on the ground is no fun) but too far front on the uphills & you spin the rear tire too easily(fun fact: even casual cyclists can develop more torque than a typical car just standing on the pedals.)

For me, it's all about behavior. I want that front end to be predictable. the softer it is, the more violently it reacts, & I'm not into that. That trait is exacerbated on forks without speed sensitive damping, too, so it's not unreasonable to run those even stiffer.
  • + 1
 Yeah I wouldn't go any softer than a medium spring at 155lbs. For reference, I ran the medium spring when i was about 155lbs, moved to the firm spring once i was riding faster. So I imagine the soft spring is way too soft regardless what damper you're running unless you're sub 140 lbs. Also its best to make sure you're damper oil level is proper before you decide on your spring rate.
  • + 2
 I wear old t-shirts from high school (26 now), they work just fine
  • + 1
 Louden always surround by the ladies.
  • + 1
 hey, who created pinkbike ????
  • + 1
 t-shirt and jeans... everytime, everywhere
  • + 1
 have you seen that booty near Graves? Smile
  • + 1
 Ride Naked.
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