Nobrakes' Wheel Prep Formula for (nearly) Flat-Proof Off-Road and Dual Sporting

There seems to be a lot of confusion around this subject - what is a nearly flat proof wheel preparation formula, but still retains maximum traction, feel, and performance. This is my recipe for that. With this prep formula, I have never had a flat. Never. That's after tens of thousands of miles of off-road, dual sporting, and off-road racing in scores of hare scrambles and enduros in all weather conditions and all terrain conditions.

This is oriented primarily for off-road slanting riders. By that I mean your typical dual sport ride might include a few miles of pavement, but mainly you are hitting the trails and using pavement mainly to get there and connect the trails. If you cruise at 75+ down the interstate for hours at a time, this is likely not the best setup for you. Use your judgment.

A buddy of mine recently bought a new set of wheels, so I bought his old set as a spare, front and rear. They are in great shape. So here is what I do to prep a set of wheels. I will use these for hare scramble racing, enduro racing, riding at off-road parks, and dual sporting - connecting power lines and trails using sections of pavement. The pavement on these rides is typically around 50 to 100 miles or so, mostly back roads and state highways, rarely interstate.

I will show the rear wheel only in this guide. I do the front *exactly* the same, except I would use a Pirelli Scorpion MX eXTRa Mid-Soft. Use whatever is best for your terrain, it varies by location. If you aren't sure, find a local trail riders association or local racing web site, and ask the racers what they use. Try a few out, and pick what you like the best.

Step 1. Gather all the parts. Here is my new-to-me complete wheel, two new rim locks, ultra heavy duty tube, and the tire. I'm going to mount a trials tire on this rim. That way, when I race in some venues where a trials tire is best, I can just swap on this wheel. I run a knobby on my other wheel set, I recently tried a Dunlop Geomax MX51 and it's very nice.



I prefer Bridgstone Ultra Heavy Duty:




Look how thick this thing is! Where I'm pinching it, that's only 2 layers of rubber. As you can see, it is THICK. It's also HEAVY. If you are an ounce shaver, you will cringe when you heft one of these tubes. But if you want "nearly flat proof", this is the ticket.






Here are the rim locks. Like several other folks here, I prefer these Motion Pro Lite-Locks.




Step 2: Drill the hole for the 2nd rim lock. Most rims come pre-drilled for the valve stem, and one rim lock near the valve stem. You need to drill opposite the first rim lock for the 2nd one. The 2nd rim lock will:

1) hold the tire on extra well, even at very low pressure - no slipping!
2) hold the tire completely on the rim in the (unlikely) case of a flat, keeping it from slipping off and therefore decreases the chance of a wreck, also if this happens 20 miles from camp and you don't have tools, you can nurse your bike back to camp without destroying your rim
3) do a pretty good job of balancing the wheel, certainly good enough for DS speeds

Locate the place to drill the 2nd rim lock hole by running a string or piece of wire through the 1st rim lock hole and stretch it across the center of the hub:



And on across to the other side of the rim. Where it contacts, drill the hole mid-way between the spokes closest to where it crosses:



Use a center punch to make an indent so your drill bit doesn't wander:




Start with a smaller bit first, then drill it!








Go up a few bit sizes and drill again, gradually make the hole larger, until you get to a 3/8" bit:







Step 3:

Install a new rubber rim strip. Center the hole over the valve stem hole.



There likely will not be a hole for the even the 1st rim lock, let alone the second one. So cut those two with an exacto knife, like this:






Step 4: The Lite-Locks come with a pad, make sure and stick that on the back. This will space the rim lock out a little bit from the rim to help make it easier to install the tire:




Step 5: Using your valve core tool, remove the valve core from the UHD tube. It will suck in air and self-inflate a little bit.






After it equalizes, use your mouth on the valve stem and inflate as much as you can to "lung pressure". Fumble around and try and get the valve core back in before it all leaks out. :-) The purpose of this is so that the tube will not fold up and crease during installation, and cause a flat the first time you pressure it up. The pressure should be about like this, as you support the tube on a finger:

 

Step 6: Use talc to "lubricate" the inside of the tire and the outside of the tube. This will reduce friction during installation and in combination with pre-pressuring the tube to "lung pressure", it helps to keep the tube from folding and creasing during installation and causing a flat when you pressure it:






Spread it all the way around:




And on the tube, too:




Should look like this, now:




Step 7: Get out your irons, I like the blue ones.




Step 8: Pay attention to any "direction of rotation" marking on the sidewall, and lay the tire on top of the rim. Place the bottom bead into the wheel well on one side of the rim. The on the other side, use three irons and work the bottom bead over the top rim edge. Using a spritzer bottle of water to help lubricate the rubber/rim can greatly aid installation:






Step 9: Now ready for the rim locks. Just lift the tire bead and install it, no big deal. Partially install the rim lock nuts to keep them from falling back into the rim well.








Step 10: Now ready for the tube. Lay the talc'd tube up on top of the assembly with the valve stem above the valve stem hole:






Start at the valve stem, and start stuffing it in there. Don't worry about inserting the stem into the hole just yet. Notice that with "lung pressure" in the tube, it's easy to stuff in while retaining its shape and it's not folding all over itself and getting kinked up, etc.




With the tube stuffed in all around, it should look like this, now.




Fine tune the alignment of the valve stem at this point, and using both hands, get your hands in there and lift the bead with the backs of your hands while you use the fingers of one hand to push the bottom bead down, and the fingers of your other hand to manipulate the tube and stem to find the magic spot where the valve drops through the hole.




Get a nut on there quick before it disappears back inside the rim. :-)

 

Step 11: Spoon the top bead over the rim. Not much to this. I generally start at the valve stem and work my way outwards in both directions. Make sure to push the rim lock nut in, so that the tire bead is free to drop in between it and the rim. Make sure the rim locks press in and out freely. If they don't, the tube might be caught in between the rim lock and the tire bead/sidewall. Make sure and solve that before proceeding, as that will cause a flat as you air up the tire for the first time.




Step 12: Spritz a little bit of lubricating water around the bead of the tire. This will help to seat the bead.

Step 13: Air up the tire to seat the beat. Here you will over inflate the tire in order to seat the bead. Then air it back down to running pressure. Most tires have a line or something to use as a reference. That line should be equidistant from the rim around the circumference of the tire. In this photo, the line is not equidistant, and the bead is not yet seated, even though there's about 40 lbs of pressure in there:




After taking the pressure up to about 55, it seated, as you can see here:



Just about done!




Step 14: Set your desired running pressure. If this was a knobby, I would stop here, at 12 lbs. And if it was a front tire, I would never go below 12 lbs. The front is, well, it's the one out front taking all the hard hits from rocks and stuff. Generally, 12 is considered 99.9% pinch proof in most conditions. But if you're riding in an area with lots of square edged sharp rocks, 13-15 lbs might offer a little better survivability without giving up too much in pliability and traction. But with the rear, you have more flexibility in pressure, I consider anywhere from 10-12 lb to be about right for a knobby, I generally run 12.




But since it's a Trials tire, it gets its traction fundamentally different than a knobby, it needs to be very flexible to wrap around objects, it needs to run much lower. A real trials rider would probably run 3 or 4 lbs of pressure. But I'm running about 7 lbs, that's decently low for trail riding and hare scramble racing and will still work very well in the roots and rocks, offering phenomenal traction but still offer decent pinch protection in combination with the UHD tube. So I'm running it on down to 7 lbs.



Install the valve stem cap. I like a metal one with a valve core remover built-in. Note that the pressure is so low, that the valve stem doesn't stick up very high. Don't worry, though, with two rim locks, it's not going to slip and tear.




Step 15: Tighten both of the rim locks. Torque to 12 N-m. Clearly, this is a critical step. No need to over tighten, but make sure you get to at least 10-12 N-m (Newton-meters).








Ok, that's it! This tire is ready to get a sprocket, a brake rotor, and be installed on the bike for a ride, race, or whatever. The rim locks will keep it from slipping, the low pressure will offer tremendous feel and traction, and the ultra thick tubes will resist even the pinchiest of pinch flats. And like I mentioned in the opening, with this prep formula, I have never had a flat. Never. That's after tens of thousands of miles of off-road, dual sporting, and off-road racing in scores of hare scrambles and enduros in all weather conditions and all terrain conditions. So this has worked extremely well for me over the years. I have thought about going totally bullet proof and using a mousse, but I have yet to have a flat with this setup, and that's riding and racing in the harshest of conditions, so I can't really justify the expense and relatively short life of a mousse when this works so well. If it absolutely has to be bullet proof, then nothing beats a mousse. But for my amateur racing and dual sporting purposes, this formula has proven 100% reliable for me so far.

One last thing, don't forget to periodically check the torque on the rim lock nuts. Then tend to work themselves loose over time, and a loose rim lock is like having no rim lock at all, don't want that.

 

good stuff NB.

 

Thanks! I figured with some of the recent discussion on the topic, I'd use the opportunity from just acquiring my new-to-me rear wheel to post up the formula that has been very successful for me. And I know a lot of that above is basic stuff, but I think a good review of the fundamentals is never a bad idea, not to mention I'm sure there are plenty of folks for which the information is new. We were all there once, there's absolutely no shame in that.

I just got back from a 3 hour practice ride and have another race tomorrow morning a few hours away. I hope everyone is out riding and enjoying a flat-free weekend.

 

very good info.I thought I knew how to fix flats but had some trouble lately and had to go back to "school".
I understand running low pressure w/ sharp edge rocks.Don't you think a little higher pressure would be better when anticipating punctures from thorns?

 

I don't see how running higher pressure is going to stop a puncture. At least around here, you don't really have to worry about thorns, they are generally not big enough or strong enough to pierce a m/c tire. That's not to say some locales don't have some that can go through a motorcycle tire. I used to get them in mountain bikes on a fairly regular basis, but never a m/c tire. But if foreign object puncture from thorns or otherwise is a fairly common occurrence, personally I would consider a mousse. Or maybe Tire *****.

 

I've been running baby powder in my bicycle tires for years now... most people just think I'm crazy about it helping prevent pinch flats.

Glad to see other people doing cost effective things

 

Smells nice, too.

 

Yep!

Now I just run Stan's sealant... tubeless