In Mainstream MTBs force a fit compromise our friend in shred Chris asked,

I remember you posting about your custom pump bike a while back. Since you don't have the seated vs standing compromise on a bike for pumping/jumping, how did the geometry on that bike differ from all the mainstream DJ'ers out there? I vaguely remember something about a much higher RAD angle.

Hey Chris, I’ve been waiting for someone to ask. Thanks!

Short answer

Compared with a dirt jump bike like the Specialized P.3, my pump bike is

• Lower in the bottom bracket.

• Shorter in reach.

• More balanced between the wheels.

• Has a more upright riding position.

• Is easier to ride without a hip hinge.

• Is a lot faster on the pump track and more boosty in the jumps.

Keep reading for the juicy nerd details.

What is a dirt jump bike?

A dirt jump bike is kind of a cross between a hardtail mountain bike and a BMX bike. They’re meant to be fun and maneuverable. Most commonly:

• Wheels are 26 inches.

• Forks have 100mm of travel.

• Seat tube is very short and seat is very low.

• Head tubes are short and bars are low unless you use a tall riser bar.

• Drivetrains are single speed.

• Cranks are standard 170mm length.

• Chainstays are very short. This brings the RAD/chainstay leverage ratio near 2.0, which makes these bike feel poppy*.

  • *Poppy, snappy, and playful are common bike review terms. The higher the ratio between RAD and chainstay, the more force gets delivered to the rear tire when you pull the bars. High-ratio bikes hop, jump and pump-manual easier with less bar pull. If you know how to corner, they snap from turn to turn.

• Frame reaches tend to be shorter than modern trail bikes, but they are not short compared with average rider height. My most recent Specialized P.3 had the same reach as my Stumpy 29.

• Short chainstays and moderate reaches create a rearward weight bias, with about 35% on the front tire and 65% on the rear.

See Best way to fit a DJ bike.

Because they are precise, dirt jump bikes are ideal for skills training. Here’s me on a P.3 coaching The Fix junior team in 2007 (We won the Mountain States Cup overall).

Because that bike has such a rearward weight bias, I bring my foot forward to load the front tire. Even then, you can see the rear tire pushing more than the front.

Dual slalom racing on a smooth track is increasingly rare but always rad. As I recall, I won this one. I’m leaning forward on that P.3 to make the front wheel track.

I’ve ridden and loved every iteration of the Specialized P frame from 2000 to 2022. It’s the quintessential DJ bike: small, quick, efficient. A great bike for pump track, dirt jumps, skate park and other smooth, pump-intensive riding.

A DJ bike like a P.3 is rarely pedaled, but the layout is built around those cranks.

What is a pump bike?

Necessity is the mother of invention, or so they say.

When my right hamstrings tore off my hip in September 2024, the first MotoCranx prototypes were already in production. MotoCranx let you mount your pedals directly to a threaded bottom bracket, like motorcycle footpegs:

Why did I make MotoCranx?

1) I thought they might help people to learn to pump. They do.

2) I noticed that the longer my cranks were, the more the top of my right hamstrings hurt. 150s felt better than 170s, so I wanted to try 0s.

That pain was a major warning sign from decades of hard riding on long cranks. After my hamstrings got reattached to the bone, I slapped the proto-MotoCranx onto my trusty P.3 and used that rig for most of my rehab.

With my feet side by side I could ride without a hinge. While my legs recovered I stayed positive and curious, rather than depressed. This was key!

I built up to 200 laps on this kiddie track. 20 sets of 10 in smooth, soothing meditation.

Riding MotoCranx on a standard DJ frame worked great, but I wondered. What’s the ideal frame geo for a bike that will never be pedaled? Time for a proof of concept.

I started with these requirements:

• Use every component from my P.3. Match the head angle so the only variable I’m testing is pump-specific geometry tweaks.

• RAD must be 77cm just like the P.3.

• Must be rideable in a natural, upright standing position. Because of genetics and/or lifestyle, most people simply can’t hinge well. To that end,

• RAD angle should be around 65 degrees, like a motocross motorcycle. My P.3 RAD angle was 58 degrees, like a trail MTB, which required a hinge to ride well.

• Front/rear balance must be 40%/60% for F1 cornering balance. That’s 14% more front wheel traction than the P.3.

• Get the highest RAD/chainstay leverage ratio possible.

The end result has:

• Massive bottom bracket drop. Because no cranks!

• A much shorter frame reach.

• Slightly longer chainstays.

• RAD 77cm.

• RAD angle 65 degrees.

• 40%/60% fore/aft balance.

• RAD/chainstay ratio 1.9. I can get to 2.0 with shorter chainstays, but I don’t want to compromise cornering balance. (My trail bikes are around 1.5).

Pretty sweet!

How do a dirt jump and pump bike compare?

The pump bike’s riding position is more upright because my feet are lower and the bars are closer.

How does the pumpcycle ride?

It’s easy to ride in a comfortable, upright stance. Hinging is optional.

Footpegs make pumping very easy. When I put clients on it — click! — all of a sudden they can ride the pump track. The skill transfers straight to their pedal bikes.

It corners like crazy. The 40/60 fore-aft balance and ultra low bottom bracket make it rail! No tire knobs, no chain, no weight on the hands, and no worries.

It’s super fast. The motocross stance unlocks full leg power, and the high RAD/chainstay ratio delivers mega pump to the rear wheel.

It’s so damn fun. To me pump biking is the essence of shred and the forge of flow. The lack of drivetrain forces me to look ahead, pump everything and get into phase with the terrain wave.

As a side effect, my pumping skills and trail vision are massively upgraded, which shows up as PRs on my favorite descents. This cracks me up. As I turn 57, with artificial shoulders and a permanently downgraded right leg, I’m FASTER than 20 years ago when I won a national DH title.

Plus perfect training for emoto!

Did I mention? I’m having more fun than ever. See DHing with no cranks is so fun!

What will be even better?

I’m now making pump bikes for those in the know. They feature:

• BMX parts. Burlier and cheaper than MTB parts. This drops the bike price.

• 20”, 24” and 26” wheel sizes. Smaller wheels pump fastest, bigger wheels are mellower.

• Even lower bottom brackets. Better cornering, less bar rise. See Why low rise bars are ideal.

• Optional 100mm cranks for pedaling around and for pump track race starts.

I’m playing with the model name “PMX” as in pump motocross. Each frame is designed for its rider.

PMX 20. Dialed for a 5’2” rider.

PMX 24. Dialed for 5’9” rider.

PMX 26 for that mellow ride.

What fun to discover a new way of riding. What do y’all think?

Lee

Ride your own pump bike

Here are two ways:

1) Slap MotoCranx onto a bike you have. Pick up a cheap BMX bike or give an old frame new life. Megan races her vintage Gary Fisher to a pump track worlds qualifier podium:

Cost: $99. Buy MotoCranx here.

2 ) Rock a custom pump bike. I’ll make one just for you. Yes, it can have short cranks. Cost starts at $999 for a complete bike.

Curious about pumpbikin’? Message me here or email me at leelikesbikes@gmail.com.

Photo by Dario DiGiulio.

At least two CORECROSSers raced crankless. If the course doesn’t require pedaling, why not?

• Natural motocross stance

• More leg range, both higher and lower

• More leg power

• Lighter, simpler, cheaper bike

Plus it’s punk AF. You don’t have to ride what the corporations tell you to ride. #sramdontloveyou #neitherdoesshimano

I love riding 0mm cranks

My day-to-day training/play is on MotoCranx. I’m having hella fun and improving on the bike and emoto.

Yesterday I rode this 2023 Specialized Demo Race with MotoCranx at Trestle Bike Park in Winter Park, CO. What a machine. Silent except for the growling tires and the sighs of Mother Earth.

OMG it was so fun!!! Every trail from green flow to black rocks to technical jumps to huge senders felt fluid, powerful and easy.

Plus it was faster!!! Despite not being able to pedal, I PRed segments on Rainmaker, 36 Chamber, Long Trail, and Double Jeopardy.

That blows my mind because those segments started flat, and I had to pump for speed. Turns out pumping every bump like a maniac works pretty well.

Or, as national BMX champ Danny Caluag told me,

“Fun is fast.”

What do you think?

Lee

Axe your chain and free your brain

MotoCranx cost $99 and fit any bike with a threaded bottom bracket. Pump track, dirt jump, bike park, downhill.

This week I picked up the keys to a shop space in North Boulder. More specifically it’s in Gunbarrel near two breweries and the dirt jump park.

I’ve done a lot of things in the bike world over the past 40 years, but this is my first shop. I am excited, nervous, overwhelmed, focused, and all the things.

The name of the shop is Dialed. I will focus on the following activities.

Bike fitting. I’ll be doing fits on mountain and gravel bikes with a balance of pedaling power, comfort, and handling. Emphasis on comfort and handling.

Custom frame geometry. I’ll continue to create hardtail, full suspension and gravel frames that fit individual riders absolutely perfectly. I’ve been selling frames only. With the shop I’ll also sell complete bikes.

Selling and building Mistress and Dialed bikes. I will focus on delivering high-quality builds at moderate prices. If you want something fancier we can do that too.

Demo rides. I’ll have a small fleet of bikes you can try. My approach to geometry is so different from the mainstream, you have to feel it. Warning: These bikes are comfortable, easy to ride, and very capable. Most people who try one buy one (or two).

Cycling consultations and therapy. Come on in and sit down. Enjoy a cold drink. Let’s talk about your riding, and I’ll help you make it more satisfying. When you speak with me you access my holistic approach to riding skills, physical training, mindset, bike fit, custom bike creation, sports psychology, life coaching, hardcore racing, soul riding and living with joyful intention. If the best answer is a bike from another shop, I’ll make sure you get the right size and fit.

Joyrides. Dialed becomes the physical home for the joyride movement I am now officially leading. We’ll do group rides out of the shop. We have easy access to the local dirt jump park, Valmont Bike Park, and tons of bike paths, plus short drives to great MTB trails.

Servicing my clients’ bikes. Once your bike is in the stand for a fit, we might as well get it running perfectly. I’m too detail oriented to work on my own bikes, but I’m perfect for yours!

Here’s the sign for the front door.

Elyse and I are setting up the shop this month. I already have a handful of bikes to build for my people. I expect to open the doors August 1.

Stay tuned for more details!

Lee

Hi and welcome back to 32er Week. So far:

A brief history of MTB wheel sizes

Diameter and bumps

Contact patch and cornering

What about fit?

In today’s episode I ride the Lenz Leviathan 32. I found that bike awesome in the straights but disruptive in the corners.

Read more

Our friend Dave sent a letter by carrier pigeon:

Hey Lee! How’s it going?

My Mistress has been really working well for me. Thank you!!

My skills are advancing and I am ready to start shredding our local black diamond trails. I’ll be doing bigger drops and getting more air. I need your advice on my rear shock settings.

Just to refresh your memory, I have a Fox 36 fork with 160 mm and a RockShock Super Deluxe Ultimate (love that name) with I think 145mm of travel. I really haven’t played with the default RockShock settings except for air pressure.

The suspension has been working well on flowy trails with smaller features. However, I did a 4 foot drop Saturday and felt a stinger in my neck on a good landing. I may have too much air in the RockShock, I am running pressure slightly high to make climbing a little more efficient (which I do a lot of). I am going to try lowering pressure slightly. I didn’t get near bottoming the shock.

Any other changes you would recommend? Would love your help!

Thank you! Dave

Dave!

It’s great to hear from you. Stoked you’re enjoying the bike, and that it’s helping you advance your riding. Those bikes are so quietly competent, my riding is better than ever too.

Here are some tuning tips to help with those harsh landings.

Read more

I’m no fan of modern bike sizing, but I’m a huge fan of real advancements.

Index shifting was a big deal. Rather than going by feel — rat-tat-tat jingle-jingle-jingle oops wrong gear— while trying to climb some rocky fire road, you just clicked your shifter and whoa you were in the gear you wanted.

Who remembers the little switch on the XT thumb shifter that put it in friction mode? That was for the shifting nerds who demanded to shift by feel and honor the spirit of friction shifting.

Read more

Here are a couple options:

The original TowWhee strap

TowWhee was invented by MTB racer and genius Eric Landis. I'm proud to say I helped Eric with his gate start. As a matter of fact, when his hips lined up just right … his crank snapped!

Eric loves riding with his kids. He needed a tow strap that was easier to use and had some elasticity to smoothen out the pull. So he made one and called it TowWhee. Tow … Whee!

I’ve towed a weaker rider and been towed by an electrified rider. TowWhee’s quick-connect and elasticity make it easy and non sketchy. The full MTB setup costs $60. TowWhee lives in your pack until you need it.

I’m stoked to see Eric offering TowWhees for bike, moto, snow and water sports. I hope he’s cashing in!

https://towwhee.com/

New at Sea Otter: Kommit

Kommit’s spring-loaded cable lives under your saddle, coiled and ready when you need it. The base unit plus a springy bungee cost $99.

Kommit Towing Systems

I’ll let Miles tell you about it.

Theoretical comparision

I’ve ridden the TowWhee and never thought it needs improvement. The length of the line and the elasticity are perfect. Oh, and it comes in kid and adult tunes. Eric really is a smart dude.

If you find yourself attaching and detaching often, the Kommit seems like the hot ticket. Downside: The short bungee doesn’t provide as much elasticity as TowWhee, which can make your towing herky-jerky

Bottom line: If you prioritize quantity of tows, consider bolting a Kommit under your saddle. If you prioritize quality of tows, throw a TowWhee in your pack.

Who out there uses tow straps?

Lee

Dial in your bike with Dialed v2 and the DiRT tool

The ebook, print book and Kindle of Dialed v2 include access to the DiRT MTB modeling tool and Dialed v2 online. Run the numbers before you run your credit card.

This is a love story. A story of love that has passed, and love that is to come.

A story of a man who loved biking so much he bought himself a Mistress trail bike. From the moment they met it was a perfect match — a match made in heaven, or maybe the DiRT bike fit tool. Rocky old trails became smooth new waves, and former PRs became fond memories of a slower time.

His Mistress trail bike made him so happy he thought, my girlfriend will love riding one too! He dreamed of uniting his two loves — her and riding — and fantasized about evening rides, MTB vacations, and long, slow kisses at the bottoms of long, fast descents.

But alas, fate has its own plans. Her path led elsewhere and he was left with his Mistress bike and her frame. What he really needs at this point in his life isn’t another life partner. No, not yet. Right now he needs to sell her frame and get a sweet Mistress hardtail.

One of you, my friends, can become part of this love story.

For sale: Mistress GoodOnya frame

Size: M3 for riders 5’7” to 5’11”

Color: Kung Fu Green

Suspension travel: 180/160mm or 160/145mm

Shock: 210x55mm or 210x50mm (not included)

Fore/aft balance: 40/60 like an F1 car

Condition: Brand new never ridden

Paid: $2,000

Selling for $1,500 plus packing and shipping

Interested? Email Aaron at asp@p0v.net

Learn more about the Mistress GoodOnya with Warm Embrace Geometry.

I swear we’re all living a Dead Kennedy’s album. As society crumbles, the big MTB brands choke on their greed, and I become that gray-bearded shred guru with solutions to mountain biking problems, I’m feeling more punk than ever.

I needed some shoes because I wore mine out. I needed cleats to go with the new shoes. I bought some cleats. But they’re not compatible with my ancient Shimano SPD pedals, and I got a tendon strain that’s taking forever to heal.

I’m not complaining that I’ve gotten 25 abusive years out of those Shimano pedals and they still work perfectly, but DAMNIT I thought all SPD cleats work with all SPD pedals! Around 2000 they made the exception to that rule. Never mind that those pedals were cheap then and work perfectly 25 years later … I’m feeling rebellious.

An ad for Tenet Osiris Clipless Pedals came across my feed. In a fit of rage against the machine, I ordered a pair. The pedals come with a free service then free bushings and bearings for life. The clip-in part can be removed and replaced. So you can theoretically ride this pedal for … 25 abusive years.

Kind of like the Shimano pedals, which never needed any service. But it’s the principle! If these pedals work half as long and I support a small business, we win.

Who out there supports smaller businesses? No venture capital, no holding companies, no lobbyists, no executive salaries, just bike people helping bike people.

Lee

Custom frame built just for you

When you hire me to create a frame for you,

1. You’re getting a frame that’s designed to make you feel comfortable, safe and confident. Everything fits you to the millimeter and degree. Save money: Use parts from your current bike.

2. You’re directly supporting me, the frame fabricator and the person who does the build. The holding company and venture capitalists get nothing — because here, they don’t exist. This is MTB performance with a punk ethos.

Learn about custom full suspension and hardtail frames at www.mistresscycles.com. You can choose between the ultra rebellious Mistress brand and the I-believe-science-more-than-marketing brand Dialed. They both get laid out by this gray-bearded shred guru. For the reasoning behind these bikes see the book Dialed v2.

Special edition Mistress mullet for Tommy Mello. “It feels like my trials bike and BMX bike got together and had a mountain bike” Learn about his sweet build.

Lee!

I’d love to know your thoughts about tire inserts, where they offer advantages and where they don’t.

I know they are popular, they add a lot of rotating mass, they are a pain to install, they support soft sidewalls, they might add some pinch flat protection and they might act like run-flats (maybe). They also reduce air volume and change the ride feel.

I’ve also heard that a heavier casing (like a Double Down) offers similar benefits in a lighter, more convenient package.

Would you be willing to do your genius MTB nerd thing on this issue?

Tom

Tom!

Why yes, fine sir, I’ll be willing to apply my genius MTB nerd powers to this important issue. For reference here are three popular tire inserts:

CushCore. The enduro and DHer’s choice for ride damping and rim protection. I’ve ridden these with a flat tire (because I couldn’t make the repair). Heavy.

Vittoria Air Liner. Similar to CushCore but lighter for XC and trail.

Tannus. Clever option that lets you run tubes. No sealant. No hassles seating the beads. I need to try this one.

For inserts in general:

Pros

• Allow lower tire pressures. Smoother ride, more traction.

• Allow lighter casings. Less weight and more suppleness.

• Reduce pinch flats. Fewer trailside repairs.

• Protect rims. Fewer wheel issues.

Cons

• Cost money.

• Can be hard to install.*

• The tire can still be punctured or cut.*

*Less true with Tannus

Can go either way

Heavier. It takes more work to get them rolling, but they carry speed and resist deflection more than lighter setups.

You might benefit from inserts if

• You get pinch flats.

• You damage your rims.

• You have a hard time hooking up in turns.

• You’re getting beaten up by bumps.

• Your bike feels frenetic in the gnar, and you want a smoother, mellower ride.

If you’re pushing your limits down loose/chunky trails, you might benefit from lower-pressure, more cushioned, more stable tires.

Hardtail shredders: Hmm, how about an insert in your rear tire?

Why I don’t use inserts

I’ve experimented with CushCore and decided to rely on heavier tire casings. Here’s why:

• CushCore is a pain in the ass to install.

• You can still puncture or tear your tire. I’ve cut a tire with CushCore inside then …

• It’s harder to make on-trail repairs. Maybe you end up riding a flat tire, or you’re wearing an insert over your shoulder.

I don’t see increased weight as a downside of inserts. Heavier wheels is one of those pro/con features like slacker head angles and shorter chainstays. Heaviness can be a negative or a positive depending on your perspective.

When I rode with CushCore, my bike was fast on gnarly downhills, but it was so stable and muted that it was less fun (yeah that’s a thing). If I was chasing downhill speed above all else I might rock heavy inserts. Now I’m chasing fun, which demands convenience.

I ride normal trail casings in the front and heavy casings in the rear. This gives me a nice combo of pinch flat resistance, cut resistance, and greater rotational inertia. When I flat (rare) I slap a tube in there and keep riding.

For reference here are the “enduro” and “downhill” casings for big tire brands. For trail riding I do fine with a GRID Trail or Double Down rear at about 25 psi.

• Specialized: GRID Trail, GRID Gravity

• Maxxis: Double Down, Downhill

• Schwalbe: Super Gravity, Super Downhill

• Kenda: Advanced Enduro Casing, Advanced Downhill Casing

• Vittoria: Trail Enduro/DH

But I gotta try Tannus

Tannus might be the perfect compromise. Easy to install with no high-pressure bead seating. No sealant to dry out. Good flat protection. Increased rotational inertia. Yeah, I gotta try this.

Who’s rocking Tannus? Who’s rocking inserts?

Lee