Mongoose dolomite fatbike? 7spd, disk brakes, INEXPENSIVE

[Ch00paKabrA]

Just an FYI for the Dolomite and Beast builders (as I may be one this Spring). the biggest turn off to me about the bike was the strait 1 1/8 steerer tube and I want to put a suspension fork on it. the problem was the Reise racing and the Rockshox Bluto Fat bike suspension forks both used a tapered steerer.

I did manage to find a few lower quality suspension fat bike forks on AliExpress if you are interested. Here are the Links:

http://www.aliexpress.com/item/-/32279930268.html

http://www.aliexpress.com/item/-/32280079915.html

http://www.aliexpress.com/item/snow...spread-135mm-suspension-fork/32244377171.html

At least one of them appears to have preload and lock out but since I don't have one as of yet, I can't speak to their quality which is probably Walmart quality.

the mid-drive looks awesome. Enjoy it. Aren't there wide cranks used on the motorized bikes that would work without any customization?

Edit: yes, there are wide cranks: here is a link to a set:

http://www.google.com/url?sa=t&rct=...=o98zeaesb22zoObQQsNiyg&bvm=bv.85142067,d.eXY


That should clear it. it is a whole set but maybe they are available individually.

 

[lbeck37]

Thanks for the info on the crank. I actually thought I was going to need more offset and thought I was going to have to put a spacer between the arms! Is it hard to cold bend a crank arm and get an offset but keep the pedal straight?

 

[d8veh]

Is it hard to cold bend a crank arm and get an offset but keep the pedal straight?

To bend the crank, you should heat it to red hot first to anneal the aluminium. You will be able to bend it about half an inch before it work-hardens. You then heat it back up to red hot again and you can move it another half an inch. Don't try and bend it further than it wants to go. You'll feel it stop. If you keep the heat local, you can control where it bends. With a 170mm crank on the right side, you need maybe a 175mm one on the left to allow for the bend to keep the pedals on the same radius.

 

[lbeck37]

I think tahustvedt used a 170mm SR Suntour XCT Left Crank Arm which gave another 19mm offset. If you combined that with a little cold bending like e-waka did you would have your 25mm/1" offset without the cut and bolted look.

http://endless-sphere.com/forums/viewtopic.php?f=28&t=63250

http://endless-sphere.com/forums/viewtopic.php?f=28&t=62518

http://endless-sphere.com/forums/viewtopic.php?f=28&t=65663

Thanks for the links, I had seen e-waka's post before I began but I couldn't find it again. It was really the one that made me wonder if I could do it too, given that I'm on the road in an RV with not much more than a grinder, drill and a saws-all for modifications.I've been thinking of a vise mount for a trailer hitch receiver so I could have a vise for things like bending cranks.

 

[lbeck37]

I didn't have to thread the bottom bracket. The Bafang doesn't use the threads in the BB. You take all the stuff out of the bottom bracket leaving just the shell, and then you slide the Bafang's "snout" through the shell, slide the motor support bracket (with ridges that jam into the BB and help prevent the motor from moving) over the snout and then thread the nut on and tighten it tight That's all it takes to install a Bafang BBS02 into a bike with a 68 mm wide BB. Surprisingly Mongoose bent the chainstays in far enough on the Dolomite so that I could be trim enough on both sides to get the BB narrow enough to let me get the nut on the Bafang snout.
--Larry

When you get a chance, Id love to get some stats from you about this mod ..like

1. how much do you weight and how much does the entire bike weigh now

2 . top speed on flat road and top speeds in each specific gear

3. climbing abilitiy

Thanks for all your help. Im thinking I am gonna do this mod soon.

If I do this mod, I will probably offset the left crank/ pedal by getting 2 crank arms and cutting the circular part of the crank arm that attaches to the crank , completely off , then line it perfectly up to the inside to the other complete crank arm so both holes line up perfectly and it can be fastened to the crank . The hole on the outside crank may need to be drill out a bit wider , but leave the inside crank hole alone so it will fit tightly once the nut is put on.

This should give you the offset needed, and be barely noticeable .

I weigh about 200#, a stock Dolomite weighs a ton, 48# comes to mind. I weighed my 522 Whr battery and it was 7.5# with its mount. I think a 36V 500W BBS02 system adds around 12#. The bike definitely feels a lot heavier than my wife's 26" mountain bike with the same motor/battery. I bet it's close to 70#.

On the top speed it is faster in 7th than I can spin the 32T front chainring. Using the throttle I saw 24 mph on the display and climbing (Bafang speedometer set for 28" diameter) and it was going about as fast as I wanted (remember, this is the bike that when I clamp the front brake the front wheel can go into a violent shutter!). It's fun but this bike is not about top speed. I haven't checked the speed in the gears. My motor is the 36V 500W and the 48V 750W motor in other bikes feels way faster. My 36V 500W motor does just fine (and was available at good price) but bikes I've ridden with the 750W really move and are less sensitive to what gear you're in.

The bike climbs real good if you drop it in a lower gear and let the motor spin. I found that with the BBS02 that when climbing it's important to be in a gear that has your pedals spinning at a pretty good rate and then the motor feels like it's at its "sweet spot" and will just motor right up.

I think the left crank arm can be made from a standard left arm and bending another 20 mm into it without heat. The Bafang left arm doesn't have much offset and is junk anyway. I think that either the Bafang right arm could be bent/sanded to clear or maybe I standard right crank with all the chainring mounting cut off.

I think for doing serious mountain bike things that a mid-range ($500?) mountain bike with a fork, better components and being lighter would be a better bike to start with. For driving on bike paths and trails and not having to worry about running into dirt or sand this is a great bike. The soft tires make up for no suspension fork most of the time but one would be nice.You also get tons of attention. Also, the Dolomite totally loves having the motor, without the motor I had trouble going much above 5th gear. With the Bafang installed I drive around in a middle gear and only shift up occasionally and keeping up and catching up to (and leading friends is no problem. It will be interesting to see what sort of range difference I see between my wife's bike and mine, I've got to be using more juice moving those meaty (and loud) tires.

 

[ebikedelight]

Lbeck, I sent ya a P.M.

Thanks for your info.

 

[ebikedelight]

Mongoose is releasing a much higher quality fat bike called the ARGUS. In comparison to the dolomite, its much lighter , alloy frame ,
better components , nicer tires, drilled out rims , more gears , and more abilitys for future upgrades. It will also be available in many different frame sizes and colors.

Price is supposed to be around $900 . Its interesting to note, that the Dolomite used to be priced around the $350 mark , and has now been marked down to $191 . Thats about a 40% markdown on previous price ....and even at $191 , im sure there is significant profit in the big box stores selling it at this price. This just goes to show the markup on these over seas bikes . I wouldnt doubt that the ARGUS, will eventually be marked down to $500 , in a year or so from now.

 

[wesnewell]

That's great for pedal riders. It sucks for people that want to put a big motor on it. The dolomite would be the better choice. If you want better components, just put them on the dolomite.

 

[ebikedelight]

That's great for pedal riders. It sucks for people that want to put a big motor on it. The dolomite would be the better choice. If you want better components, just put them on the dolomite.

Well the problem for me is, the dolomite only comes in 1 frame size.

In 6ft -5" tall, with a 36' inseam. I think the dolomite is 17" ..I need 21-22" .

My plan is to make my dolomite a ebike, with a hub motor, then give it to my wife, and then I purchase a higher end fat bike , and make that a ebike either with a BBS02 or another hub motor.

 

[leelorr]

Bikesdirect.com sells reasonably priced fat bikes in the different sizes. The problem is that we can't see which ones have a BB design that will allow us to shave down the BB width to allow the BBS02 to fit. Forum user "Gridlok" has his own Fatbike blog at:
https://electricfatbike.wordpress.com/2015/01/13/bbs02-fat-bike-conversion-kit/
On his blog he has a lot of good info about converting fatbikes to use the BBS02.
In that blog he states that he has converted a few of the cheaper fatbikes to use the BBS02, but that the actual bike frames do not always match the frame photos on the bikedirect web site, so you can't tell which bike would work. Bikes Direct does sell a single speed fatbike with a 68mm BB, but then you have to figure out how to convert it to have multiple speeds. I read a lot about IGH hubs thinking that might be one solution, but it appeared to me that everyone on the forum here who has tried using an IGH for off road with an electric bike ended up breaking the IGH because of the torque (except for the $1400 Rohloff IGH). I don't know enough about bikes to know if we could just buy a (larger sized) single speed fatbike with the 68mm BB from bikesdirect.com and then put a different hub in the rear and/or spread the rear frame a little to allow a cassette hub to fit or not.
I just keep hoping that someone will come out with a good solution to this that doesn't cost $550 like the adapter for a BBS02 to 100mm fatbike BBs.

 

[2old]

Ibeck, thanks for the information; did you cut down the bottom bracket?

 

[2old]

leelorr, the rear spacing on the SS is 135mm which would fit a cassette hub and, for instance, the Deadeye Monster which has 4" tires (according to BD). However, the main problem (TO ME) is the rear dropout won't accept a derailleur. BD responds to questions the same day if you want to ask them anything.

 

[leelorr]

Thanks for the information.
I think I would rather face welding a derailleur hanger on (or using the super epoxy stuff that has been recommended for this purpose) than face the issue with the wrong size BB. Of course, I guess that the fat tire might get in the way of the chain going to the rear gear set even with the right width hub.

So much to learn!

 

[lbeck37]

Ibeck, thanks for the information; did you cut down the bottom bracket?

Yes, I cut some off each end with a saws-all and then ground down the final with an angle head grinder. My biggest problem was keeping the BB square which I actually failed to do but since the Bafang is just clamping between the ends, it catches the high point and it's OK. i tried to use a 4" long water pipe nipple (forgot what size) (a very close fit inside the BB) as a guide but I kept grinding into my guide pipe. It would have been better if it wasn't such a small end to guide since it was threaded but think next time I will do what my bike shop suggested- take the last bit off each end using the disc sander on my bench sander at home. I will need to set up some fixturing but I should be able to hold it very square to the BB.

 

[cjh]

If you are worried about it being square enough, see if your local bike shop has a bottom bracket facing tool and get them to tidy it up for you after you have got it pretty close.

 

[lbeck37]

If you are worried about it being square enough, see if your local bike shop has a bottom bracket facing tool and get them to tidy it up for you after you have got it pretty close.

Great idea! They could take it down very nicely and not risk running the grinder into the chainstay, which I did and covered with a piece of black Gorilla tape

 

[2old]

Thanks Ibeck; was going to say great idea cjh, but realized it had been already stated.

 

[markz]

I saw that exact bike at a crappymart instore, I dont know if I liked it, but steel is good and disc brakes is good. Perhaps you could do a fat rear tire, with an upgraded front suspension fork making the front tire narrower.

Here is one I found while looking for Moongoose Dolomite at Walmart.ca

http://www.walmart.ca/en/ip/wooly-bully-fat-tire-bicycle/6000188616883
http://www.overstock.com/Sports-Toys/Polaris-Wooly-Bully-Fat-Tire-Bicycle/9243077/product.html

http://www.overstock.com/Sports-Toy...fccid=BF453GW7SOW3JQ2M2IESJFUVNY&searchidx=12

http://www.overstock.com/Sports-Toy...efccid=BF453GW7SOW3JQ2M2IESJFUVNY&searchidx=5

http://www.overstock.com/Sports-Toy...efccid=BF453GW7SOW3JQ2M2IESJFUVNY&searchidx=4

Honestly with all my problems of finding a steel frame bike that is new, I found the motherload right here.

http://www.overstock.com/search?key...sortOption=Lowest+Price&TID=SORT:Lowest+Price

Now if only a $1500+ steel full suspension bike that "needs work" can come into my hands on a very cheap basis!

 

[arkmundi]

http://endless-sphere.com/forums/viewtopic.php?f=3&t=62023&start=150#p1002658 ..Just an FYI for the Dolomite and Beast builders ....

Thanks for the set of links on a fat-bike build up. I've never really considered a fat-bike before the eruption of the Storm eBike. And never ridden one. So I'm a follower of the thread and will consider it a potential..

 

[diggler]

I got this one.http://www.ebay.com/itm/Fat-Tire-Beach-Cruiser-Mens-Flat-Red-Wheels-NEW-7-SPEED-DISC-BRAKES-/271768706917?pt=LH_DefaultDomain_0&hash=item3f46ad5f65
It has a steel frame, and plenty big for you 6'5" tall guy's, but it has a 100mm BB.
I put a sick bike parts four stroke jack shaft kit on it, and a four stroke 49cc bike engine. http://www.sickbikeparts.com/catalog/product_info.php?cPath=21&products_id=110
The BB that came with the kit was 68mm so I cut it in half and added a pipe over the two ends and drilled and roll pinned.
This gave me the 100mm I needed.
This frame extends the down tube past the BB and then the chain stays T off from there about 4" past the BB.(or so I didn't measure)
I just ran out to the garage to measure the down tube width past the BB and it's only 53mm.
So this might be a candidate for you guy's make shifting the BBS02 system.
You'd still have to contest with the chain line and the cranks but still a good solid BIG frame.

Do you guys think it be easy to put a rc motor on this?

 

[diggler]

Thanks for the links to the cheap suspension forks btw. The solid ones are better for winter biking though.
I've thought about putting a monark fork on this in the summer. http://www.bikeberry.com/bicycles/accessories/fenders-forks/monark-type-2-dual-springer-motorized-bicycle-fork.html
And a thud buster. I HATE bumps! I've run my tires below 10 psi before. Feels like a cloud.
I've also kicked around the idea of a 20"x4" with the monark fork.
Especially since as of right now I'm installing the MXUS 3kw in the rear. The smaller OD would make the bike a lot torquier!

 

[spinnerankin]

Iv recently just traded in my Full Suspension DH Bike for this fatbike, i haven't taken a shine to the red wheels so I will have them wrapped as soon as I figure out which colour, I would like some suggestions as to which hydraulic brakes ,Cranks,handlebars,Stem,Hubs,I should mount???

 

[Ch00paKabrA]

The coolest fat bike forks are from Risse Racing. They have fat forks with a strait steering tube that will fit a Dolomite. They have a dual disc single crown and 2 dual crown forks for fat bikes. the only other fork that comes with a strait steerer is the carver transfat. The only thing is; these forks will run between 3 to 5 times what the Dolomite costs.

There are some cheapies on aliexpress that are walmart quality though for around $100. Good luck.

Yesterday, I demo'd an Origin8 fatbike out on the beach and was surprised at just how well it handled the loos sand as well as the wet packed stuff. The Nuvinci hub was great.

I too am looking into this. I am not 100% sold yet though.

 

[diggler]

these forks right?
http://www.risseracing.com/store/product_info.php/products_id/324
Yah they look pretty BA!
I wonder how much this would screw with my bike? Because my forks are curved.

 

[Ch00paKabrA]

diggler, did you check out the Big Foot Extreme forks? Fat tire Dual Crown fork with 12" of travel!

http://risseracing.com/store/produc...id/60/osCsid/b2080259cdf72780404feb36cefd3373



It might be hard to justify putting a $2,000.00 fork on a $200.00 bike though.