Tales of the Big W fatty. The Hyper Mammoth.

[bychosis]

After reading the talk in the So how bad is a Big W bike, really? thread it came to pass that the Mammoth would enter my possession. As an addict of the local gumtree bicycles listings I noticed one a while ago for the princely sum of $200. It didn't sell, so I considered offering $150. Then to my excitement (or is that horror) the seller was having an oz-day weekend sale, n+1.5 kicked in and I brought it home yesterday.

As described elsewhere on the web and in the other thread this is no ordinary Big w BSO, it is a fat bike, and with that comes a significant amount of steel and a little alloy weighing in at 23.1 on my bathroom scales this morning. The tyres are huge and no doubt the tubes are too adding up to all the extra weight over what would probably be a 14kg bike other than for the wheels. It's rigid, single speed and has not much extra on it.

I have taken it for a spin short around sunrise this morning and it's going to have to go back in the workshop and then be put on a diet. You can really feel the weight in spinning up the wheels, but once there it isn't that hard to cruise along the flat. Up hill is a different story, funnily enough it feels heavy, very heavy. The steering is a bit wired too, seems to be nice and stable going straight on, but once the bars turn there is a strange sensation probably to do with the rotational inertia and changing the direction of the spinning 4kg (estimate) wheel, or it could be the geometry that appears to be a little bit too steep. Either way, something to get used to. Maybe some fattie riders might comment on the steering of a decent fat bike setup. The position is very upright and it could probably do with a longer stem, but I'm on the taller end of humans and have a long torso too. As its one size fits most, it obviously won't fit everyone, and although a more cruisy position it wasn't bad.

The chain promptly fell off after rolling out of the drive down the road and then beginning to pedal up the next rise. The front brakes rubbed for the whole ride and the left crank developed a bit of a clunk on the way home so I pushed it up the hills rather than damage something. Was ok on the flatter sections without too much power applied. Tool time next. Also need to shorten the silly-long brake cable and remove excess items like a kickstand and maybe the chain guard.

I also let down the tyre a lot. The previous owner had them quite hard, as I know heaps about fat bikes I figured the tyres shouldn't be hard so I dropped the pressure to around 15, bit hard to tell as my pump guage isn't accurate that low. The tyres still are quite firm even at 15psi using the old squeeze test. Seems the tyres are fairly stiff, next step will be completely deflating them and testing!

More to come...

[bychosis]

[thecaptn]

Does it have a hub brake on the rear?

[bychosis]

Yup, coaster brake. I think mine needs some extra grease in it. Seems a bit grabby. The US Mongoose Beast version doesn't come with a front brake at all, but our rules state there must be two brakes on a bike so they have fitted a front disc, probably the easiest solution along with a dash of bling.

Kickstand is off, minus 305g = 22.8kg

[ldrcycles]

23kg for a rigid singlespeed, my god!

[trailgumby]

A coaster brake on a a supposedly off-road bike. Well, not really. That sticker says a lot!

How are you supposed to ratchet the pedals over obstacles with a coaster brake?

Smite it with fire!

[HappyHumber]

How are you supposed to ratchet the pedals over obstacles with a coaster brake?

You're missing the point. You crush them instead with your sheer weight. BigDump is trying to appeal to the MMA/MonsterTruck loving set where brute force is (and short attention spans are) king.

[Robinho]

Having just landed in Dubai, I have seen some monstrosities in the local hypermarket which I need to investigate. Fatbike with front suspension (of a sort) twin ring, probably 6 or 7 speed cassette, some shimano stickers near the mechanicals, doubt much of the moving parts are shimano though. I think I saw cable disc brakes. Going to have a closer look to see what it actually is, what it weighs and costs.

[Kalgrm]

Good luck with that thing. It doesn't look like there is a lot to go wrong with it though.

The steering behaviour is normal to some extent. It's caused by the super wide tyre and the large contact patch. As you turn and lean, the tyre on the inside of the turn has a smaller diameter than the middle of the tyre and the grip tries to pull the steering further into the turn. It's called "self-steering". Some tyres are more prone to it than others, and it gets worse as the tyre pressure decreases. It's not really noticeable on the dirt though.

15psi is still very high for a fat bike. I run mine at 7.5 (r) and 6.5 (f) on packed gravel and tarmac, and 5 (r) and 4 (f) on sand. My tyres are 4.8" wide though. (Buy a cheap digital pressure gauge from Repco or Super Cheap Auto.)

Cheers,
Graeme

[trailgumby]

I have one of these for my pressure gauge. Seems to work well.

http://www.this link is broken/au/e ... lsrc=aw.ds" onclick="window.open(this.href);return false;

[Mulger bill]

How are you supposed to ratchet the pedals over obstacles with a coaster brake?

You're missing the point. You crush them instead with your sheer weight. BigDump is trying to appeal to the MMA/MonsterTruck loving set where brute force is (and short attention spans are) king.

The F450 of the bike world. Does it come with complimentary truck nutz?

[thecaptn]

The F450 of the bike world. Does it come with complimentary truck nutz?

I think if you're capable of putting serious kms on it you'd be able to just hang your own nutz out the back.

[silentbutdeadly]

I'm trying to giggle and applaud at the same time...and am still wishing it were me creating this Thread!!

[bychosis]

It makes me giggle too. Stupid bike, but sure to have some fun on it.

I've dropped some more air out of the tyres and they now feel squishy. No idea what the pressure is, but so far so good around the back yard and driveway. The front disc brake has been adjusted to not rub, but in doing so I've backed off th cable to much and it is now a device to slow the bike, not stop it!

My bro-in-law visited this arvo and has a little ride, said he would probably buy a real one (no offence taken). My reply indicated that you can't go and buy a real one for a laugh, and shouldn't he be putting money towards a house at the moment anyway! This toy won't cost me much (if I can help it), not much spent on parts, resale value should be similar, unless fat bikes are just a passing fad.

[trailgumby]

The F450 of the bike world. Does it come with complimentary truck nutz?

I think if you're capable of putting serious kms on it you'd be able to just hang your own nutz out the back.

Like this? For riding at night, of course.

http://www.gizmag.com/bike-balls-tail-light/37514/" onclick="window.open(this.href);return false;



Mods please delete if this crosses a threshhold

[RonK]

This toy won't cost me much (if I can help it)...

Oh yeah? Could be a very slippery slope you're on.

[koshari]

is that a plastic covered steel crank?

[silentbutdeadly]

is that a plastic covered steel crank?

Are you talking about the bike or the bike nutz?

[silentbutdeadly]

Here's a hint about fat bike tyres. At least ones with car valve tubes. Take the valve out. Put plumbers tape on the

[koshari]

is that a plastic covered steel crank?

Are you talking about the bike or the bike nutz?

the earlier, i had a feeling it may have been a good idea to quote the earlier pics coming in after that post.

[silentbutdeadly]

...thread and give the tube a big blast of lungs. Fit the cap. That's probably the right air pressure...

[cray-]

Pretty sure I've seen people taking to the rims with a hole saw to shed some weight. Not sure about the technicalities.
Mostly I'm commenting so that this thread will come up in "view your posts" so I can keep an eye on it. =D

[bychosis]

...thread and give the tube a big blast of lungs. Fit the cap. That's probably the right air pressure...

Wondered what happened to that sentence.

I rode the fatty to work on Friday. Normally takes 15-16minutes on a road bike. Took me 21 minutes and my legs were toasted. Needs some gears to be anything other than a cruise bike. To tall for hills, to low for the flats. After riding it back home of Friday arvo it wont be going commuting again anytime soon.

Gets plenty of comments though. Not many have seen a fat bike before.

I think after some time I'll get the hole saw out for the rims, then take the tubes out and run tubeless to shed some serious weight. Might try to find some old alloy bars and a seatpost to help too.

Still, its a bit of fun. I'd better try it out on the beach before I sell it too!

[ldrcycles]

And see if you can get 50% more than new price like when i sold my Repco Preset .

[bychosis]

And see if you can get 50% more than new price like when i sold my Repco Preset .

There's the challenge! Let's see, $299 RRP IIRC, plus 50% = $450. I'd say chances are slim, but it would mean $299 profit if I don't spend anything on it.