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I'm buying this for my brother mainly for deep-snow riding. The rider weighs about 120 kg (265 lbs).

26" x 4" (102mm) tires in the pictures, but I will install 26" x 4.8" (122mm) tires.

Can you see any other obvious issues with this frame?

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Seller says 4.8 inch (122mm) tires should fit. I sure have my doubts it looks to me it will be a very close fit.

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    Which bolt are you talking about? If it's the one above the BB I think you are talking about, it's actually a very clever design as the downwards shock force actually counteracts the weight of the rider.
    – MaplePanda
    Apr 17 at 1:05
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    Can not tell from a photo alone. That seat, on that bike does not look right to me. Small bump compliance on a soft tail fat bike should make springs in seat redundant.
    – mattnz
    Apr 17 at 1:53
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    @mattnz It does not look like a bike designed to be pedalled much if at all.
    – Criggie
    Apr 17 at 10:26
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    And here is the promotional material. We can see that @Criggie is correct. This is not designed as a mountain bike at all, it is in fact an electric motorbike. youtu.be/tI2-7EGFo90
    – Andy P
    Apr 18 at 11:00
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    @MikeWhite They are not available in the EU because they are not legal in most parts of the EU. And the assertion that it doesnt have enough power to climb hills is crazy. 1000W is 4x as much power as most regular cyclists that can climb hills just fine. Even professional cyclists rarely exceed 1000W for more than a few seconds
    – Andy P
    Apr 18 at 21:57

2 Answers 2

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To answer the part: "Can you see any other obvious issues with this frame"

Upon some further investigation it does not seem like this bike is fit for purpose. The manufacturers website indicates that they have designed it as a scooter rather than a mountain bike.

Charges the scooter full in 6 hours

The marketing video from the manufacturer also suggests this is the design intent of the bike:

In terms of design flaws in a bike designed for snow riding, ask yourself the following questions:

  1. What is the purpose of the rear suspension in the context of a fat bike designed for snow riding?
  2. With high volume tyres AND rear suspension, why does it have a sprung saddle?
  3. What is the purpose of a long travel suspension fork on this bike? Situations that require a long travel fork also expose one of the weaknesses of high volume low pressure tyres (burping). The fork also doesn't seem to be from a known suspension manufacturer - can you get it serviced easily?
  4. What is the purpose of a large front chainring on a fat bike? Can you tell me the gear ratios used? Since it's 1x, is it a narrow-wide ring?
  5. The rear gearing used is not clear from the manufacturers website, but the photo shows a low end touring groupset that I would not consider suitable for MTB.
  6. It's unclear if the rims are tubeless compatible
  7. Can you find a geometry chart for it? Every good bike brand produces a geometry chart because this gives the customer an idea how the bike will fit and handle.

Given all of the factors above, I would assess that this bike looks like a mountain bike, but most likely performs nothing like a mountain bike since the company designing it does not seem to have given any thought to its function as one.

As a side note, I spent some time googling and can't actually find anything that I would consider as a 'proper' electric fat bike. I did manage to find a few projects fitting a Trek Farley with an electric conversion kit.

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I suspect you're referring to the main pivot (aka bottom bracket pivot) where on this bike the lower shock eye connects with the seat tube and chain stays of the bike. Most full suspension bikes I'm familiar with have a single bolt thru main pivot. The "bolt" is sometimes called the pivot axle. There are associated sealed cartridge bearings, sleeves, bushings, shims, washers. Sometimes just a plastic sleeve bearing or IGUS bushing is used in lieu of ball bearings contained in a cartridge bearing. This set-up is found on lower quality full suspension bikes. My 2016 S-works Stumpjumper has a total of 10 pieces that make up the main pivot assembly. The center piece (literally) is the axle which is essentially a hollow M15 bolt, 77.5mm long, that spans the width of the bike and threads into the frame's native threads on the drive side chainstay.

It appears you have a type of 4 bar suspension, perhaps a "DW-Link" suspension that will have good anti-squat characteristics. Anti-squat is the resistance to activation of the suspension during acceleration. This would be especially useful here as it appears the bike is equipped with some sort of powered assistance which will put more torque to the rear wheel (and thus more tendency to squat under pedal power).

Powered assist is welcome here as well because it's gonna require some wattage to get those 4" to 4.8" wide tires rolling, especially through or on top of deep snow. Being full suspension brings the bike's weight up quite a bit over a hardtail, so that is a factor in the required power equation. A fit, muscular, 120 kg man should be able to generate decent power, but riding a fat bike through snow--deep or otherwise--will require substantial and sustained power output.

Regarding the increase in tire width to 4.8" I question the benefit of the additional tire footprint versus the increased weight and rolling resistance inherent to the extra width of the tires. Before purchase of the wider tires, I would make sure there are not going to be any clearance issues. Not only laterally (will the 4.8s rub the chainstay?), but also the wider tires will typically add to the overall wheel diameter which will require more power to get rolling and, if there remains any clearance from tire to seat-stay bridge (if one is present, can't tell from the side view photo) that narrowed space will become a choke point for snow and ice to build and rub the tire. Same issues for the clearance between tire and the lower aspect of the seat tube. Also you must think about rear suspension activation and the necessary clearances required. I don't feel the additional tire width would be at all beneficial to this set-up.

Finally, the size of the chainring is ala a road bike. Larger chainring means higher gearing requiring more power. Whatever power your brother can generate supplemented by the wattage of the assist system, is the additional speed possible from the higher gearing necessary or even useful if the bike is to be used to travel on two wheels in winter weather? I'm no pansy, but that situation is worrisome to me even when I can get past the non-usefulness of a high geared fat tire bike, especially off road or thru snow cover.

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  • This ain't no DW-link, that's for sure.
    – Paul H
    Apr 18 at 17:38
  • nowhere nearly as sophisticated.
    – Mike White
    Apr 18 at 21:34
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    Great point about the gearing. Upon closer inspection of the pictures on the manufacturers website we can see they are totally the opposite of MTB gearing.
    – Andy P
    Apr 18 at 22:04
  • thanks for all the information . I greatly appreciate
    – Mike White
    Apr 19 at 9:40

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