Hello, and converting an old Moots to BBSHD

nikhintz

10 mW
Joined
Mar 31, 2022
Messages
22
IMG20220331213433 by nik1924, on Flickr

Hello to everybody from Guam. I am new to Ebikes and the forum, and perhaps a bit rusty and antiquated to the much changed world of bikes. I have decided to convert my 2001 Rigormootis to a mid drive ebike with the ultimate goals of being my commuter/grocery getter and weekend trail explorer. Somewhere in the nebulous world of ground shipping delays across the Pacific to this tiny speck of land, that isn't quite the US, lies a BBSHD kit with a 52v, 17.5AH battery. Most of the other updated parts have already landed on island, with only a couple small missteps so far. I have learned that the frame will only accept a 160mm rotor without hitting the chainstay. At least i have a spare 180 for the front now

The drivetrain will be the stock 46 tooth up front with a Box 11-50 tooth 9 speed cassette out back. Brakes are Deore 4 piston, 180mm front and 160mm rear. I am working on sourcing a beefier set of wheels to cope with the added weight of bike and my now much heavier self. finding 26inch QR wheels that seem worth buying has proven challenging.

Anyhow, if anybody has words of advice, encouragement, or general verbal abuse, I would love to hear it.
Thanks
 
It is weird how the crack in the wall and the front tube stem lined up perfectly from that camera angle.
Other then that it looks great, keep the pictures coming. :thumb:
 
nikhintz said:
I have learned that the frame will only accept a 160mm rotor without hitting the chainstay. At least i have a spare 180 for the front now
Depending on your speeds, weights, and trails, the rear 160mm might not be a problem. Looks like you have cantilever mounts so could use those with some Koolstop pads for good braking performance.
 
I suspect the 160 will be ok, I'd need to look pretty hard to find a hill with more than 400-500 feet of elevation change. The high point on the island is only about 1200
 
Missing packages and mission creep strike again. The set of used wheels that I ordered on ebay have disappeared somewhere between here and Wisconsin. 26" QR wheels of reasonable quality are getting pretty scarce these days, so it looks like building up a set has been added to the project. Deore hubs with Sun MTX33 rims and DT 13 gauge spokes should be up to the challenge.

I am definitely experiencing a bit of cognitive dissonance on this project. So much effort trying to strip weight from the bike over the past 20 years. Now the 22 pound XC hardtail is going to weigh somewhere around 50 and have wheels that look like they belong on a small motorcycle.
 
13ga spokes are a mistake. The wheel will sustain higher loads more reliably and durably with thinner spokes.

But overall, the bike seems pretty well sorted out, if also overkill for Micronesian terrain.

If I were starting from a clean sheet, this is one of the very few times I'd opt for a plastic frame (carbon reinforced). Rigid frame, rigid fork, 2.6-3.5" tires, 40-65mm wide rims, 1x8 Microsoft Acolyte gearing, stainless steel chain, Avid BB7 brakes. The only challenges you really face are sand and salt. (And making adventure out of leisure.)

Anyway, keep your beautiful Moots frame washed off and indoors, lest the ocean eat holes in it.
 
I'm expecting the bike to routinely be rolling at 375-400 lb combined weight, at least until I drop some of the extra that I've grown over the years. So overkill seems just about perfect, I can always put the old lighter stuff back on should I feel the need.

The spokes were a function of what I could get without buying a full box of each length. I've already blown well past the initial budget I had in mind. As it looks now the only surviving parts from the previous build are the seat and post, fork, headset, stem, grips, and front brake rotor. As an aside, the Thomson post and King headset have been there since the initial build in 2001.

Regarding carbon, I'm pretty squarely of the school of thought that people my size should not play with ultra light parts. It's a lesson I have learned by breaking lots of fancy parts. I still have a couple black carbon fiber tattoos on my fore arm from an exploding carbon handlebar
 
nikhintz said:
I'm expecting the bike to routinely be rolling at 375-400 lb combined weight, at least until I drop some of the extra that I've grown over the years. So overkill seems just about perfect, I can always put the old lighter stuff back on should I feel the need.

I was mostly referring to the MTB setup, especially the long travel fork. Heavy weight is a reason not to use one, because they're not easily tunable for heavy and highly variable weights.

Regarding carbon, I'm pretty squarely of the school of thought that people my size should not play with ultra light parts.

Yeah, I wish it were easy to find a heavy carbon frame. But I think it's safe to generalize that field grade carbon MTB frames are stronger than titanium MTB frames. The benefit in this case isn't weight, but resistance to corrosion.
 
I've had good luck running Titanium pump shafts and fasteners in my past coral aquaculture hobby.
Quoting this link:
https://www.azom.com/article.aspx?ArticleID=1226#:~:text=Titanium%20resists%20corrosion%20by%20seawater,showed%20no%20evidence%20of%20corrosion.

Fresh Water Corrosion - Steam
Titanium resists all forms of corrosive attack by fresh water and steam to temperatures in excess of 600°F (316°C). The corrosion rate is very low or a slight weight gain is experienced. Titanium surfaces are likely to acquire a tarnished appearance in hot water steam but will be free of corrosion.

Some natural river waters contain manganese which deposits as manganese dioxide on heat exchanger surfaces. Chlorination treatments used to control sliming results in severe pitting and crevice corrosion on stainless steel surfaces. Titanium is immune to this form of corrosion and is an ideal material for handling all natural waters.

Seawater General Corrosion
Titanium resists corrosion by seawater to temperatures as high as 500°F (260°C). Titanium tubing, exposed for 16 years to polluted seawater in a surface condenser, was slightly discolored but showed no evidence of corrosion. Titanium has provided over thirty years of trouble-free seawater service for the chemical, oil refining and desalination industries.

Exposure of titanium for many years to depths of over a mile below the ocean surface has not produced any measurable corrosion. Pitting and crevice corrosion are totally absent, even if marine deposits form. The presence of sulfides in seawater does not affect the resistance of titanium to corrosion. Exposure of titanium to marine atmospheres or splash or tide zone does not cause corrosion.

Erosion
Titanium has the ability to resist erosion by high velocity seawater. Velocities as high as 120 ft./sec. cause only a minimal rise in erosion rate. The presence of abrasive particles, such as sand, has only a small effect on the corrosion resistance of titanium under conditions that are extremely detrimental to copper and aluminum base alloys. Titanium is considered one of the best cavitation resistant materials available for seawater service.

Stress Corrosion Cracking
ASTM Grades 1 and 2 are essentially immune to stress-corrosion cracking (SCC) in seawater. This has been confirmed many times as reviewed by Blackburn et al. (1973). Other unalloyed titanium grades with oxygen levels greater than 0.2% may be susceptible to SCC under some conditions. Some titanium alloys may be susceptible to SCC in seawater if highly-stressed, pre-existing cracks are present. ASTM Grade 5 with a low oxygen content is considered one of the best of the high strength titanium-base alloys for seawater service.

Corrosion Fatigue
Titanium, unlike many other materials, does not suffer a significant loss of fatigue properties in seawater.
 
I was mostly referring to the MTB setup, especially the long travel fork. Heavy weight is a reason not to use one, because they're not easily tunable for heavy and highly variable weights.

The fork is only 100mm travel, and air sprung so tuning is fairly easy.


Yeah, I wish it were easy to find a heavy carbon frame. But I think it's safe to generalize that field grade carbon MTB frames are stronger than titanium MTB frames. The benefit in this case isn't weight, but resistance to corrosion.

This bike has lived, not visited, at or near sea level for the majority of its rather long life. costal Alaska, Hawaii, Florida, costal Maine, and now here, and has been coddled for exactly none of that time. The biggest issues I have encountered with corrosion were about a third of an aluminum bottom bracket cup turning to grey mud and some corrosion on the steer tube, just above the crown race on the old Marzocchi xfly 80 fork. Titanium is just about the most corrosion resistant consumer grade material in use, and unlike many of the resins and plastics that hold the carbon fiber into shape, it is not damaged by the intense UV that this tropical island provides.
 
Well, I know of Ti bikes that hung up on beach house verandas and got holes eaten in them that way. So be vigilant.

Hi Luke!

The corrosion resistant properties of pure or commercially pure Ti are different than those alloyed with aluminum and vanadium, as most bike frames are. Typical California or Texas conditions won't bother them, but salt spray plus dissimilar metal contact (from aluminum and steel parts) can be the kiss of death. That turns the poor things into exotic batteries with unfavorable self-discharge qualities.
 
As with all of the machines I work on, be it a bicycle, a truck, or an airplane, I'll keep an eye on it.

In all honesty, the thing that concerns me most out here are the battery and motor thermal management. Average day time highs are typically 28-30c, and something black left out in the sun can easily top 60. I have not really been able to find much in the way of operating specs for the motor or controller. Looking at the motor casing, I can see the cooling was a consideration, although not a priority, based on the nearly vestigial fins. Would it be worth attaching a bit of additional radiative area?
 
I wouldn't worry too much about overheating the motor. Climbing 1000' vertical on a hot day here will get mine close to 60C. As long as your average speed is reasonable, the wind keeps the motor cool. I used to be worried about overheating mine too, so I installed a cheap thermometer to keep an eye on it. It is rarely an issue. I would stop and let it cool if it got over 60C.
 
Chalo said:
Well, I know of Ti bikes that hung up on beach house verandas and got holes eaten in them that way. So be vigilant.

Hi Luke!

The corrosion resistant properties of pure or commercially pure Ti are different than those alloyed with aluminum and vanadium, as most bike frames are. Typical California or Texas conditions won't bother them, but salt spray plus dissimilar metal contact (from aluminum and steel parts) can be the kiss of death. That turns the poor things into exotic batteries with unfavorable self-discharge qualities.

Hello Chalo my friend! I hope you are well!

I can definitely see dissimilar metals contact with the Ti getting nasty if it wicked humidity in the interface. I would coat interfaces in a corrosion inhibitor dielectric gel in the places you need to clamp steel or aluminum against the Ti. Perhaps disassemble and clean and re-apply the dielectric gel every couple years.

I would consider a potted battery pack if you're regularly eating salt spray off your tires riding.
 
I like the idea of a potted battery for a number of reasons, aside from weight, but as I've said, that is pretty low on the list of concerns.

The sand out here makes it so beach riding is pretty tough without some pretty fat tires. Plus when I'm on the beach I'd much rather be standing near a grill with a cold beverage in hand, so salt spray should be fairly limited.

I used to ride the beach in Alaska, and definitely had issues with galvanic corrosion there. But without fail, it was an aluminum, magnesium, or ferrous part that took the hit. Titanium is just so far down the galvanic scale that it will always be the cathode. Unless you are using carbon fiber or platinum group metals, but I don't like carbon fiber, and platinum makes a lousy bike.

Don't get me wrong, this is about the most aggressively corrosive environment you can get, short of living downwind from an erupting volcano. So corrosive in fact, that keeping airplanes from turning back into aluminum ore is the primary reason I'm on this island.
 
Parts are finally starting to trickle in, hubs, spokes, and rims arrived yesterday, and the motor kit has landed on island. I'm just waiting on customs clearance to make the pick up.

It has been a while since I have laced up a wheel, now I just need to dig out the truing stand to get them trued and tensioned up. I might even tie and solder the spokes, just to see if I remember how.IMG20220417185332 by nik1924, on Flickr

Deore disc hubs, Sun MTX33 rims, DT 2.34mm spokes with brass nipples. Not exactly light parts, but they look nice.
 
Moving right along. The wheels are trued and tensioned, with some fresh tires. There is not much extra space in the frame for a fatter tire, 2.25" seems to be about the practical limit. The only surprise so far is that the output drive gearcase was hitting the chainstay and needed a little over 4mm of spacers to clear, the LH brace ring also needed a corresponding stack of washers to fill the extra gap.
IMG20220418220025 by nik1924, on Flickr

Everything in the kit seems fairly well put together, the only thing that I'm not particularly fond of is the non keyed connector from the motor to the controller harness. Those super fine pins and nothing more than a couple printed arrows to align the connector seem like an easy way to bend pins.
 
IMG20220419183007 by nik1924, on Flickr

Pretty much finished aside from cleaning up the wiring a bit and waiting for the bleed kit to arrive so I can shorten the brake hoses to get rid of that ridiculous loop out front. Top speed seems to be somewhere around 30 mph on level ground, and I definitely run out of gear and leg speed before the motor tops out. I've put about 25 miles on it so far, and the range with the 52v 17.5 AH battery looks like it will be somewhere in the neighborhood of 30-35 miles, at least the way I'm riding it now, the throttle and higher power setting are just way too fun. Total weight came out at 56 pounds, so between the electric kit, much heavier wheels, and rack, it gained about 33.5 pounds in the conversion.

The chainline needs to be moved inboard a bit, but from what I can tell, the only two real options for that are the Luna eclipse and the Lekkie. As it sits now, the chainring lines up with the third smallest cassette gear, and makes it so the lowest two gears are pretty much a no go. I am leaning more towards the 48 tooth Luna setup, that would move everything about 6mm inboard from the stock chainring, and hopefully let me use a broader spread on the cassette. Unfortunately, those parts do not seem to exist at the moment. If anybody has other suggestions or options to help solve this, I'd love to hear them.

Thanks for following along
 
nikhintz said:
Parts are finally starting to trickle in, hubs, spokes, and rims arrived yesterday, and the motor kit has landed on island. I'm just waiting on customs clearance to make the pick up.

It has been a while since I have laced up a wheel, now I just need to dig out the truing stand to get them trued and tensioned up. I might even tie and solder the spokes, just to see if I remember how.IMG20220417185332 by nik1924, on Flickr

Deore disc hubs, Sun MTX33 rims, DT 2.34mm spokes with brass nipples. Not exactly light parts, but they look nice.

What do you recommend for a truing stand? The cheap ones in looking at seem to have problems with the precisioning of the various arms
 
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