26 inch - 4" fat tire build for sand

[liveforphysics]

Most pre-made for sale fat ebikes I've ridden on sand experience motor overheat and/or motor controller failures within a few minutes of the power demands imposed by sand.

Very high power ebikes run fine on sand with any tires if you can keep your speed up.

Weirdly, when doing comparisons with top speed on sand, smooth street slick tires actually sustained a higher top speed on sand than knobbies.

Like MadRhino mentioned, big diameter is just as important for reducing drag on sand as being wide.

 

[gobi]

E-HP, what brand/model of tire did you end up going with?

I got them off of eBay for $10. CST Fringe 24x2.8" Shipping was $15, so I bought 3 to spread out the fixed shipping charge, so they came to around $15 each delivered.

but I probably should have bought 4 for the price.

Nice, I found them, but the seller had only 1 left, lol, yes, you should have bought some more.

 

[gobi]

Most pre-made for sale fat ebikes I've ridden on sand experience motor overheat and/or motor controller failures within a few minutes of the power demands imposed by sand.

Very high power ebikes run fine on sand with any tires if you can keep your speed up.

Weirdly, when doing comparisons with top speed on sand, smooth street slick tires actually sustained a higher top speed on sand than knobbies.

Like MadRhino mentioned, big diameter is just as important for reducing drag on sand as being wide.

Ah hah,

Smooth vs nobby - I am not doing any hill climbing, maybe a ride back to the parking lot at a 8% incline. I don't see many smooth tire options for fat 4 inch tires.
I found a rolling resistance charge of different 4 inch tire brands and found that Schwalbe Big Jims or Jumbos were the most efficient knobby tires.


Big diameter - 26 vs 24, so I should just get a 26 inch and call it. I can always put a small wheel/tire in the rear with the motor.


26 inch tire opens up a LOT of option in bike choices for my ramen budget, I am looking at Mongoose Dolomite, I think I will click the magic button on amazon (cheaper than walmart) and get it.

The motor will be here late this week, so having the bike I can measure it to order the spokes,

Wait I should be able to find the Mongoose factory wheel measurements somewhere on the web?

 

[gobi]

Depends of the sand. Loose surfaces like larger diameter wheel just as much as wider-softer tires. Cutting on the wheel size might not be your best option, unless the sand is compact.

I spent a bunch time reading some of your threads on tire size, cross fit etc,
Going bigger makes sense for my riding plans, so I went bigger and with a 26 inch mongoose dolomite.

Here is what I have till now:
1. Mongoose Dolomite 26inch red - sourced from Amazon, it is already here thanks to my free 1 month prime.
2. Rear Hub - Bafang g062 unlaced (aliexpress)
3. Battery - 48v 15ah downtube used battery off jehu, actual capacity might suck, going to measure it later this week.
4. Tire - Chaoyang Sand Storm Street tires from Italy (wow, shipping was not that bad)

I need to measure and order spokes to lace the bafang hub,

Where should I order the spokes from?

 

[Chalo]

You need to calculate spoke length first. For that you'll need the ERD (effective rim diameter, which is the spoke nipple seat diameter plus 3mm).

Use Grin Tech's spoke calculator to derive the spoke lengths you need. Depending on what the lengths are, you may be able to get them from a local or online bike shop. Empirebmx.com has many lengths available for as little as $0.25 each (plus nipples).

If the length is uncommon, you may have to find a specialist who cuts spokes to order. Sunnyspokes.com is one source I'm aware of.

 

[gobi]

You need to calculate spoke length first. For that you'll need the ERD (effective rim diameter, which is the spoke nipple seat diameter plus 3mm).

Use Grin Tech's spoke calculator to derive the spoke lengths you need. Depending on what the lengths are, you may be able to get them from a local or online bike shop. Empirebmx.com has many lengths available for as little as $0.25 each (plus nipples).

If the length is uncommon, you may have to find a specialist who cuts spokes to order. Sunnyspokes.com is one source I'm aware of.

Thanks Chalo,
I plan on swing by my local bike shop and picking up 2 long spoke and then use them to measure the ERD.
Yes Sir, I watched a few wheel lacing youtube videos made by Grin,

I have to take apart a perfectly good laced wheel/tire to take measurements, it took a bit of self convincing on my part not to buy another fat tire unlaced rim, the rim are sooooo expensive and let's not mention shipping.

 

[Chalo]

I plan on swing by my local bike shop and picking up 2 long spoke and then use them to measure the ERD.

Your LBS most likely has "rim rods" for measuring ERD. If you want to use those, you'll have to bring them an unlaced rim.

 

[calab]

I should bring in my motorcycle rims to the lbs and get them to measure the erd with their gadget, I messed up last time by a few millimeters and it wasnt like I rushed it, I measured 8 times but I obviously measured at the wrong spot of the angled nipple hole, to far inward on the nipple bowl or to far outward of the nipple hole and maybe what I really needed to do was just measure the flat part between the spoke holes. Still haven't got a clue with hours of trying to google it. Its just something stuck in someones head in a custom motorcycle shop somewhere.

 

[gobi]

I plan on swing by my local bike shop and picking up 2 long spoke and then use them to measure the ERD.

Your LBS most likely has "rim rods" for measuring ERD. If you want to use those, you'll have to bring them an unlaced rim.

Gotcha, I will ask them, the local fufu store has a full service part, nice people.
Thanks,

 

[gobi]

I should bring in my motorcycle rims to the lbs and get them to measure the erd with their gadget, I messed up last time by a few millimeters and it wasnt like I rushed it, I measured 8 times but I obviously measured at the wrong spot of the angled nipple hole, to far inward on the nipple bowl or to far outward of the nipple hole and maybe what I really needed to do was just measure the flat part between the spoke holes. Still haven't got a clue with hours of trying to google it. Its just something stuck in someones head in a custom motorcycle shop somewhere.

I hear you, I have never done this before and the hub is not here yet.
I don't want to end up with 36s of extra spoke,

so measure flat part and + x mm?

 

[calab]

Well rereading what I posted I guess one could measure the inward part of the nipple hole and the outward part of the nipple hole, divide by two and that be your #.

26" fat tire in 4" flavor measures out close to 29" but having the right tire pressure psi is the key, like I said somewhere I tried 3.5 but I think 2.6-3.0 would be the sweet spot more mostly pathways and some single track and rocky areas, rarely river sand or river mud.

 

[Chalo]

so measure flat part and + x mm?

The best at-home method is to use a thin dowel, welding rod, or other straight stick that will fit through the spoke holes. Put it through directly opposite holes (count to be sure) and carefully mark the points where the stick or rod exits the spoke holes on the tire side of the rim. Measure this distance, add 3mm, and that's your ERD.

Repeat the measurement at a few different headings, in case the rim is slightly ovalized. If you get different measurements, average them.

 

[calab]

Many ways to do it, I used two old spokes like you see in many youtube videos

Then I tried metal string for pictures and muffler mounts because it does not stretch

On the 8th measurement check I even shoved a tape measure in there

I even made a protractor with pointy ends and a wing nut to get the distance to check on the tape measure. That doubles as a hub motor measurement device.

https://www.centrimaster.de/en/product/erd-measuring-gauge/

 

[E-HP]

My 5 ft tall is only 11 years old, I am pretty sure she will not be 6 ft tall in a few years.
On the other hand, is it possible to buy a frame like the one used to build this bike? Juice Scrambler
[typos edited]

At 6 ft, she might be just tall enough for a Juiced Scrambler, but you may be on your tip toes.

 

[gobi]

so measure flat part and + x mm?

The best at-home method is to use a thin dowel, welding rod, or other straight stick that will fit through the spoke holes. Put it through directly opposite holes (count to be sure) and carefully mark the points where the stick or rod exits the spoke holes on the tire side of the rim. Measure this distance, add 3mm, and that's your ERD.

Repeat the measurement at a few different headings, in case the rim is slightly ovalized. If you get different measurements, average them.

Many ways to do it, I used two old spokes like you see in many youtube videos

I think I will try the straight rod method first and then take it to the bike shop to double check my handy work.
13g rod, hmm, not sure my cleaning rods are that thin, I am sure lowes will have something,

 

[gobi]

My 5 ft tall is only 11 years old, I am pretty sure she will not be 6 ft tall in a few years.
On the other hand, is it possible to buy a frame like the one used to build this bike? Juice Scrambler
[typos edited]

At 6 ft, she might be just tall enough for a Juiced Scrambler, but you may be on your tip toes.

I am hoping she is close to 6 ft, but those frames are no go for me, I don't want her to wear her joints out from bad riding position.

If I ever get one, it won't have a pedal!

looks fancy, I love the look.

 

[gobi]

Update:
Shipping delays at the hub seller, very unethical seller, I looking at a laced kit too right now.

I found much of USED forks on FB,
the nice ones have TAPERED head (right term?)

can i make this fit in my dolomite with a kit? Fox 32

 

[Chalo]

The steel frame Dolomite looks like it has a regular 34mm bore head tube, which won't work at all with a tapered steer tube fork.

Also, the fork in the picture has been cut down much too short to use with your bike.

 

[gobi]

The steel frame Dolomite looks like it has a regular 34mm bore head tube, which won't work at all with a tapered steer tube fork.

Also, the fork in the picture has been cut down much too short to use with your bike.

Thanks! it is slim picking near me, this one had the black upper tubes, lot of people sell their take offs for upgrade.

Mostly solid front forks for fat tires :-(

 

[gobi]

Bafang order for laced hub fell through, I never received a confirmation of shipping or tracking, I asked today to cancel for refund.

Looking at Leaf now,

https://www.leafbike.com/products/beach-snow-fat-bike-kit/26-inch-48v-52v-1500w-rear-hub-motor-beach-snow-fat-tire-bike-conversion-kit-1081.html

Add on to order:
1. Temp sensor

 

[calab]

Looks good, now you just got to wait

Bafang order for laced hub fell through, I never received a confirmation of shipping or tracking, I asked today to cancel for refund.

Looking at Leaf now,

https://www.leafbike.com/products/beach-snow-fat-bike-kit/26-inch-48v-52v-1500w-rear-hub-motor-beach-snow-fat-tire-bike-conversion-kit-1081.html

Add on to order:
1. Temp sensor

 

[gobi]

Looks good, now you just got to wait

Bafang order for laced hub fell through, I never received a confirmation of shipping or tracking, I asked today to cancel for refund.

Looking at Leaf now,

https://www.leafbike.com/products/beach-snow-fat-bike-kit/26-inch-48v-52v-1500w-rear-hub-motor-beach-snow-fat-tire-bike-conversion-kit-1081.html

Add on to order:
1. Temp sensor

I gots to wait for my refund for the Bafang laced hub, they are playing games, 2 emails and still no refund,

I am guessing Leaf arrives in 2 to 3 weeks?

 

[calab]

Who really knows, its always changing due to circumstances in the world.

I am guessing Leaf arrives in 2 to 3 weeks?

 

[gobi]

Who really knows, its always changing due to circumstances in the world.

I am guessing Leaf arrives in 2 to 3 weeks?

I hear you, 3rd email out to seller, no refund for bafang yet.

Surron Forks on a Mongoose Fat bike?

I found a few surron factory forks near me, the fork is a through bolt but has straight tube and looks pretty long.

1. Will the fork fit a mongoose?
2. WIll it make the fat bike look like a clown bike?

 

[gobi]

When it rains it pours!
I came back from our spring break trip down south to find a bunch of packages at my door step:

Bafang g060 laced to bare wheel.

I am going to start the build in a few minutes,

I see they sent me Mechanical Brake sensors instead of a brake lever.