Mountain Bike SUSPENSION - Custom or Stock? Vital MTB Advanced Class

Have you ever wondered what's possible when it comes to custom mountain bike suspension tuning? Can they really dial things in for you more than stock? Is a fully tuned setup faster? Vital MTB's Brandon Turman dives into the world of custom-tuned suspension, doing multiple back-to-back runs with side-by-side video analysis. He also did mock race runs on both a stock and tuned setup. Dig in!
Fork Tuning Notes:
- Added the DSD RUNT
- Due to added support from the air spring, compression damping was lessened at the mid-valve
- Added high-speed rebound damping for control on big impacts
- Lighter low-speed / off-the-top rebound damping
- Refined rebound range
- Stock oil
Rear Shock Tuning Notes:
- Tuned to rider weight, riding style, and to balance with the fork
- 3 vs 5 weight oil
Visit www.diazsuspen... for additional details.
About The Tester:
Age: 33 // Years Riding: 18 // Height: 5'10" (1.78m) // Weight: 165-pounds (74.8kg)
"I like to have fun, pop off the bonus lines on the sides of the trail, get aggressive when I feel in tune with a bike, and really mash on the pedals and open it up when pointed downhill." Formerly a mechanical engineer and Pro downhill racer, Brandon brings a unique perspective to the testing game as Vital MTB's resident product guy. He has on-trail familiarity with nearly every innovation in our sport from the past several years and a really good feel for what’s what.
Video by John Reynolds, Brandon Turman, and Dylan Stucki

[@vitalmtb]

Have you had your suspension custom-tuned? What was your experience? Visit www.diazsuspensiondesign.com for additional details. Key Timestamps: 0:34 - Common things you can address with a custom tune 1:41 - Main areas of focus while tuning (compression, rebound, air spring) 4:32 - Back-to-back test setup 5:13 - Slow-motion comparison 8:06 - POV fork comparison 9:39 - POV rear shock comparison 10:52 - THE RACE 12:40 - Race/ride analysis and observations 19:44 - What's the bottom line?

[@pb8582]

I really love listening geeks suspension like I personally don't know anything about suspension probably why I ride a San Quentin 3. I got a rockshox RC 130 feel like I should extend it to 140. I smashed 4 tokens inside and just send it. I don't even know my weight so 90 psi and that the send. I wish I knew a bit more but I feel like people just losing it. Diaz knowledge is cool as tho!

[@riammey]

I got a custom tuned shock after my friend kept telling me about it and I thought it was a bunch of BS because you could just tune it with the knobs on your shock but then when I sent my shock to go get a service they also said they could tune it while they serviced it and I said sure why not. When I got it back it felt a lot more planted and also took the bigger hits a lot better. I ride at Windrock bike park a lot and the compressions there are insane and after each run on the stock shock I just blew through 95% of the travel each run and I didn’t like that, with the tunes set up I used only about 75% of the travel which I prefer (I like to run stiffer suspension) and I had a lot more midstroke support while having good compliance at the start of the stroke. All in all I really liked the custom tune!

[@thethepete731]

The Runt basically sounds like you turn it into a dual-rate air spring. That's really, really clever.

[@hondahardy227]

I got one a few months ago and I am never going back. I like to pump off berms and jump on party lines and the midstroke support is so much better, The biggest thing I feel is that my front end is not diving as I pump though stuff.

[@nbookie]

yep, thats what its called. more and more automotive and motorcycle tech making it into these bikes.

[@headoverbars8750]

@@hondahardy227 I'm sold... Googling...

[@harrydestcroix5516]

thethePete manitou was doing this in 2006 just search spv shock and if there was compression damping then it would be so much better

[@kevinclark9176]

thethePete actually the opposite. The Runt is about making the spring rate more linear. More like a coil spring. The problem with air is it starts to ramp up a lot at the end. The Runt effectively increases the air volume when it starts to ramp, and keeps it more linear.

[@alexkies1497]

I’ve had DSD work on all of my squishy parts for years. I’m not much of a racer, but a custom tune helped improve the pedaling efficiency on my big enduro bike, keeps the bike either planted or poppy when I want it to be, and saves my bacon when I get too excited and over roast it. Too bad no amount of suspension work can get me fast enough to keep up with Diaz.

[@esdubya]

Be careful Vital Mtb you might just become the most informative and entertaining Mtb Chanel on KZbin! Want more!

[@slampsonite]

Ran the runt in my fork this past season... won my first Pro Enduro! Shit works BROTHER

[@saenzteiger]

That guy's hair can lower any air pressure

[@SoilworkZA01]

Had a Vorsprung Fractive tune done on my Fox 34. Strava times are falling on all my descents. I feel way more in control and less like a passenger compared to the stock tune. I'm a fan!

[@sethrozic]

Both my trail and DH bike suspensions are Diaz tuned. The difference from stock is night and day, and I'll never go back. This guy knows what he is doing and I'm lucky that we live in the same town if I ever need a quick adjustment.

[@tdown73]

DSD has made me a happy customer, time and time again!

[@TrailFeatures]

Got to hang out with these guys in Sedona. Super cold dudes doing some really wizard stuff! The Runt is at the top of my wishlist this season!

[@DiazSuspensionDesign]

Awesome hanging with you too!

[@nat29single]

He lit the fork on fire! Literally!

[@DiazSuspensionDesign]

Too much rubbing alcohol? haha. We don't recommend that...

[@thomasstepat2642]

Thank you for doing this! This was awesome.... Need more please.

[@vitalmtb]

Cheers for watching, Thomas!

[@JNOTECH]

The Runt is a hell of a product. Been running it for a few weeks now and it's quite a game changer. Tokens or the MRP Ramp Control can't touch it, not even close.

[@vv3025]

questions/answers/comments/side by side in depth video analysis - all 10/10! Great stuff

[@wernervandermerwe8422]

most of these comments bashing a tuned setup is people who got their bike from the shop and never tinkered to get their suspension dialled, its literally night and day difference if you just tinker and see if you like different sag points better and put volume spacers if you bottom out too quickly. i cant imagine how dialed your bike would feel if you actually took it to a professional and get it dialled like that. the tuned suspension also looks to sit lower in the travel around berms that would make it feel so good because you are actually turning and if your front end dives like that it steepens your head angle changing the feel of your geometry.

[@kevinclark9176]

There have been some interesting aftermarket products recently but this is by far the best (from an engineering standpoint as I haven’t ridden it). The main change I would love to see would be to make insertion depth adjustable. Main air chamber volume is how you adjust main spring rate. That should be tunable. Then create a hydraulic bottom out like is part of the Vorsprung Smashpot coil conversion. Could be an add on option and would be the ultimate air setup.

[@ToshJucker]

Awesome tutorial Brandon and vital MTB, I learned a lot and it’s definitely got me thinking about taking my suspension into someone like dsd. Thanks 🤙🏻

[@trexyz2]

Great video, I love the analysis. I would love to have something similar in my area to try a custom tuned shock.

[@lux-3001]

What I learned is that with stock suspension the shot is out of focus and with a tuned suspension the shot is sharp.

[@bradbarnhart9780]

It would be interesting to see you do this same exact comparison towards the end of Summer and see if you get the same results.

[@paul_hd1875]

Reminds me of Vorsprung. I've personally made the mistake of "upgrading" parts in my suspension, both front and rear... buyer beware: if you think the bike is going to look, feel and sound stock... but deliver all these theoretical "upgrades"... it likely won't. With change... comes... well... change.

[@Radke32]

Nice test, well done. This test strongly suggest that tuning makes all the difference

[@seanknight9898]

Diggin’ that RUNT. Awesome idea.

[@typhoid77]

Great video!!!

[@ScbyPwr]

Nice.. Just been making a few adjustments in the last couple of rides. The compliance is much better with only a couple of turns on the LSC and HSC. Just have to used to the added confidence a better feeling suspension gives you.

[@chrismakin1482]

Awesome video, I'll have to get my ass to a suspension gurus shop!

[@Kev.in-Bike]

Thanks for this great video

[@florianbammes7534]

What i would like to see is some solid data testing rather then something feeling based. Put both on the dyno?!?

[@DiazSuspensionDesign]

The dyno is a great tool for replicating and putting some numbers behind what works on the trail and against the clock. So we could put both on a dyno and give people numbers that show the changes that we've made, however that would be giving away part of our formula and secrets as suspension tuners. There are also lots of different way to potentially arrive at a similar end result on the dyno, but those results don't necessarily translate to a better ride quality. Every modification and every tune starts with an opinion or a theory, then the dyno is used to quantify the changes that are being made. So yea, we completely understand that you want to see the numbers behind everything... I'm sure lots of people would find that information beneficial.

[@florianbammes7534]

@@DiazSuspensionDesign thanks for the answer. The thing is that i don't think that you give away any of your secrets. I mean everybody that is into this subject of bike nerdery knows what "tools" you have to play with. Shims, oil a file and a lathe. The secret is how and when do you use witch tool. And i don't think the dyno shows what you have done. It show the physics behind all that. And a real test implement way more forces especially into a fork. But with all that being said a dyno run would be a valuable information for your customer and the viewer of your video. If you have read this till the end....thanks man. And thanks for the video! I love that stuff!

[@DiazSuspensionDesign]

@@florianbammes7534 We'll do some brainstorming on some ways we could give you guys some data. Definitely something to think about for future content. Thanks for tuning in to this feature, definitely stoked for more to come. Enjoy the trails.

[@Baroque-Handel]

I would like to see a blind test...with an actual blindfold.

[@DiazSuspensionDesign]

@@Baroque-Handel We will call it the bird box test ! 😂

[@nathangaffran]

It would have been really cool to have split times on the rough sections.

[@Shooterthecat1]

Great work!

[@raheemgahelable]

That is some gnarly ass hair cut, sir!!! Yeeeeeeooooww 🤘🤘🤘, awesome video, great invention too!

[@davenawahine4428]

It's common for motorcycle riders and racers to re-spring and re-valve their suspension. And there are a lot of suspension companies offer DIY kits. With some cool stuff like adjustable preloaded mid and base valves, cone valves etc.. In comparison, I think mtb suspension is a bit behind the curve.

[@LaurentiusTriarius]

I destroyed some forks and shocks parts but ultimately it pays off a lot to fiddle with the springs and dampers, sometimes just playing with oil viscosity makes a ton of difference. Places like bsd remove a lot of guessing but I have fun doing it 😂

[@AlexT.A.]

Good job. 🤙🤙🤙

[@vitalmtb]

Thanks, Alex!

[@mattchay84]

Great video, very interesting. 👍

[@enrico8655]

This is realy nice stuff!

[@freendeed8410]

Incredibly interesting. Sub'd

[@vitalmtb]

Welcome!

[@oldmtbrider4273]

I can honestly say that tdt know what they are talking about i had them tune my yeti sb150 in sedona and it felt like a whole new bike and i loved it i can honestly compare it to a push suspension and the best part is they did it for free but i gave them $20 for lunch anyway

[@CuanL]

Rad video. That Runt seems pretty much identical to the Manitou IRT?

[@NastyTranquillin]

I need!!

[@WilliamCronin]

On the shock section when the camera was looking at it, the one on the left had compression lock on to medium... so thats why it wasnt returning as fast.

[@DiazSuspensionDesign]

Both were open the lever is just clocked differently on the stock one. When I tune a shock I make sure the lever is in the best possible position based on the shape of the shock and frame design. If you where riding this trail at this speed with a stock shock in medium compression setting you would pull over pretty quick because you would know something is wrong or there's a pretty good chance you would crash

[@WilliamCronin]

@@DiazSuspensionDesign sweet as

[@tim3kgt]

geronimo!!!! how was the comparison after the saddle. Thats where this trail gets really rough. The tuned suspension should really shine there as you'd be much less tired with the bike doing more of the work. understandably you wouldn't want to hike all the way back up for 6+runs and the shuttle takes 20+ minutes....#mtbproblems

[@eliasdanieli5461]

How does he wear an helmet

[@vitalmtb]

Haha. Very carefully?

[@pympin87]

it may not have been faster in this instance but you looked safer at the same speed

[@robsprimallife]

I'm a fan of custom tunes it was a huge difference for me, I think your riding style and your weight have a huge impact. I don't know what the weight range is for stock setups but I wasn't for me.

[@symmetricon1982]

Did you get more pedal bob with lighter dampened rear shock?

[@DiazSuspensionDesign]

The pedaling efficiency actually improves because you have more mid-stroke support from the air spring. On most shocks you still have some sort of compression lever or lockout that can still be used.

[@cjcox1480]

Do you work with Öhlins?

[@DiazSuspensionDesign]

@@cjcox1480 we do, but there are some limitations. Shoot us an email or service request through our website. diazsuspensiondesign.com

[@Calispeedboi]

I think you need a longer test run. like the shortest DH race runs are still 3-5 mins long

[@jamie101010]

so the tune makes it ride more comfortable, but slower.

[@whaletaleproductions7669]

Not hating, I’m sure these guys are great, but Avalanche is otherworldly awesome and gets zero love these days for some reason?

[@pierrecarriere6845]

Isn't it more or less what Ibis does with its Traction Tune ?

[@seriousmechanicing]

I need to see bro’s helmet.

[@cliffordrichardc]

what is 3 vs 5 weight oil

[@user-us1dz3ls3q]

Do it with push upgrade to 36

[@samaxel_19]

Can I use that thing into my marzocchi 350 cr?

[@rigorhead01]

Phil X!

[@theshortestcharles6886]

So the Runt is like the MRP Ramp control? Or does it work differently

[@kevinclark9176]

Different. MRP is more speed sensitive (acts like low token count at low speeds and high token count at high speeds). Suspension speed not bike speed. Problem is it doesn’t increase midstroke support or decrease ramp. So it overall is more similar to a traditional air spring. Runt gives midstroke support (more tokens in early to mid travel) but less ramp (no tokens near end of travel). Runt is meant to create more of a coil feel.

[@frits8986]

10:21 That’s what she said

[@austinnoll2869]

For spending 1200 bucks you'd think thr fork should already be all that it can be for us

[@davidthebiker2955]

How does he wear a helmet??

[@thomasli2261]

I just love this guy (no homo)

[@adlar2005]

missing the 80's music

[@miktub1555]

A lot of this is your imagination. Suspension can feel however you want it to feel.

[@NorCalRide]

Who here has used a torch on their dampener?

[@DiazSuspensionDesign]

We added a little rubbing alcohol for the effect. haha. We normally just use it for a few seconds to heat the retaining compound. You can also use a heat gun, but the torch is faster.

[@valentinowolk1564]

👊🌲🌲🌲

[@tarukmongto]

Why do you guys have an upward inflection at the end of every sentennnce??

[@cammackey8259]

So essentially the runt is an insert version of DVO's OTT

[@cben86]

OTT affects the negative champer pressure while the runt adds a second positive air chamber. They both aim for the same end result: softer off the top with more midstroke support.

[@TapsaTre]

how many usd/ lost second?

[@serjturischev9557]

buying the fork for 1k bucks and yet need to tune it,great 🤣

[@captainbufoalvarius4508]

Hey who cut Ur hair 😂

[@cyclopathtrucker8583]

Id rather just buy a fully adj shock like a caneCreek or fox float x2

[@Mediarahan003]

Judgmental ass lookin' comments section.

[@timbne]

I can't take that guy seriously with that hair

[@cdabcdefg12345]

why

[@DiazSuspensionDesign]

🤘

[@MountainPerson]

You probably should

[@darrend5563]

Diaz has been rocking the mohawk for many, many years. I lived in Durango in the mid-2000s and he's always had it. And if you don't take him seriously, you weren't listening. Better yet, go ride with him - you'll witness some "seriously" insane skills. Peace!

[@rampagerentalrepair]

Sounds like your a close minded loser to me... This guys seems to have perfected his craft!!

[@th_js]

How does he wear a helmet?

[@MountainPerson]

Whilst riding insanely fast

[@vitalmtb]

@@MountainPerson, we can confirm that!