Retrobike Forum Index

It is currently Sat Dec 10, 2016 6:54 am

* Login   * Register * Search  * FAQ



Post new topic Reply to topic  [ 128 posts ]  Go to page Previous  1 ... 9, 10, 11, 12, 13  Next
Author Message
 Post subject:
PostPosted: Tue Jan 31, 2012 8:34 pm 
retrobike rider / Gold Trader
retrobike rider / Gold Trader
User avatar

Joined: Tue Nov 03, 2009 10:00 pm
Posts: 5611
Location: Newcastle Upon Tyne
My girlfriend has gave me the go-ahead to stick this baby on eBay.

It won't be used much by her (she's getting a moped) so will not be fair clogging up her dining room!

Will stick an ad up tonight in classifieds, but read all about it here ;)

Hope a RB member will be interested.


Top
 Profile  
 
 Post subject:
PostPosted: Sun Feb 12, 2012 4:58 pm 
retrobike rider / Gold Trader
retrobike rider / Gold Trader
User avatar

Joined: Tue Nov 03, 2009 10:00 pm
Posts: 5611
Location: Newcastle Upon Tyne
Bike didn't sell on eBay, shame you still have to pay the shocking £33 ad bill!

Anyways, wasted no time sticking the Nate tires onto my moonlander for bog crawling.

4.7" big fat larrys don't always go well on bikes without huge clearance, but tried them out on the much smaller 65mm large marge rims.

Rear clearance is the main problem when fitting 4.7" tires to a frame designed around a 3.8" tire......however I gave it a go.

Image

Front rack just clears!

Image

High gear...

Image

Front left fork leg

Image

Just looks like normal larry to me,,,

Image

Front right fork leg that's offset has more clearance

Image

Granny ring on front selected but still no chain fowling, notice front mech only clears by a couple of mm though...

Image


Top
 Profile  
 
 Post subject:
PostPosted: Thu Feb 16, 2012 12:42 am 
retrobike rider
retrobike rider
User avatar

Joined: Tue Sep 30, 2008 6:25 pm
Posts: 924
Location: Near Wendover Bucks
With the mountain bike press obsessed with racing and speed how refreshing to hear tales of exploration, adventure and fun.

I have long believed that I can't be the only rider who prefers exploring interesting landscapes at my own pace to following the trail centre' way-marks at the highest speed possible.

There is so much to see in Britain and a good off-road bicycle is the perfect way to move through the landscape especially when riding with friends: Archeology, History, Wildlife, Towns and villages the ever changing seasons and weathers.

These "Fatbikes" offer a breath of fresh air to off-road cyclists as they could open up cycling to large areas of the country were traditional mountain bikes would struggle. perhaps they could even break the macho and male dominated obsession with speed and so encourage more women to ride.

Low pressure tyres can offer more comfort than suspension bikes do without the added complexity, expense and maintenance. The low unsprung weight of low pressure tyres can absorb high frequency vibrations that suspension systems cannot and yet can have enough air volume to cope with the bigger bumps. I am familiar with low pressure riding, though not with tyres of this girth, as they are also a tradition of the Geoff Apps designed Cleland bikes that I have ridden for decades. You can make ordinary mountain bike tyres run at sub 20lbs PSI by simply fitting inner-tubes that are the same size as the tyre. This is because a smaller tube can require 25PSI before it even supports the tyre wall. You also need to use extra rim tape to stop the tyre slipping on the rim and then ripping the valve off.

One problem is that like the NorCal bikes, these bikes are being designed for dryer climates and so keeping dry and post ride maintenance are likely to be issues. Especially if like me you like to ride in all weathers.
So I an looking at these "Fatbikes" with a view to building an all weather version utilising some of the methods devised by Cleland over the last 40 years.

http://www.youtube.com/watch?v=u1bYUSRhPRg


Top
 Profile  
 
 Post subject:
PostPosted: Thu Feb 16, 2012 1:33 am 
retrobike rider / Gold Trader
retrobike rider / Gold Trader
User avatar

Joined: Tue Nov 03, 2009 10:00 pm
Posts: 5611
Location: Newcastle Upon Tyne
They are great, yeah.

I never thought much about them until I discovered a north American website filled with epic pictures of explorers and there fatbikes.

I was soon hooked and realised some folk had them here....they were simply not known of, and had to be ordered in.

Scratched an itch with my mukluk in 2010, but it wasn't until I bought the pugsley last year that I done some local, solo exploring myself and fell in love with bikes again.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Feb 24, 2012 7:18 pm 
Retro Guru
User avatar

Joined: Fri Feb 26, 2010 11:41 am
Posts: 1090
Location: Calder Valley
I just don't get the fat bikes, just wierd and i can not see how they can ride well!?


Top
 Profile  
 
 Post subject:
PostPosted: Fri Feb 24, 2012 9:50 pm 
retrobike rider
retrobike rider
User avatar

Joined: Tue Sep 30, 2008 6:25 pm
Posts: 924
Location: Near Wendover Bucks
graham1975 wrote:
I just don't get the fat bikes, just wierd and i can not see how they can ride well!?


This is a theoretical response as I have never actually ridden a FatBike. It would be interesting if actual owners could comment as to whether this theory is borne out by experience. I believe that some of the hype about the capabilities of these bikes is extremely misleading.

Despite having never ridden a FatBike I have been riding Cleland bicycles for years and they share a similar ethos and also use low tyre pressures.

The Theory:
Every litre of mud, sand, or snow that is displaced by a rolling tyre weighs about 1kg. Say on soft terrain the track marks left by the tyres have displaced 1k per meter. That equates to 1000kg or one metric tonne per km of displaced materiel. And this is before you can consider energy losses due to the viscosity of the material concerned.

Quite simply put, lower tyre pressures produce a larger ground contact area and so a bike will sink into the ground less and so energy losses through rolling resistance will be reduced. Using larger wheels or fat tyres can reduce the rolling resistance further. The downside is that wide, fat, low pressure tyres can have much larger rolling resistances on smooth surfaces.

Reduced rolling resistance on hard rough surfaces.
Big volume low pressure tyres can also dramatically reduce the rolling resistance on rough hard surfaces. This is because the tyre will squish over the bumps absorbing vibration that would otherwise cause the mass of the bike to rise and fall or rotate. The energy for this vibration is subtracted from the forward speed of the bike and is much larger than that required to squash the rubber of the tyre. The mass of the moving bit of tyre is minute compared to the total mass of the bike and so very high frequency vibrations can be absorbed that no suspension systems can handle.

The bigger the air volume of the tyre the lower the frequencies that it can absorb before it hits the rim.

The Hype?

These bikes are often referred to as "Snow-Bikes" or "Mud-Bikes" but this is misleading. Fat Tyres are not best suited to all types of snow or mud.
Bellow I will list some terrain types and list the tyre type that I have found is best for each.

Soft newly fallen snow = Big wheels with thin low pressure snow tyres (or better still a ski-bike).

Intermediate snow = Big wheels with thin low pressure snow tyres (suspension is useful if the underlying ground is bumpy)

Refrozen snow = Very low pressure tyres

Hard compacted snow = Any spikey tyre at low pressure

Ice= Studded ice tyres at low pressure

Lying water = Thin rain tyres and good mudguards/flaps

Thin Gloopy mud = Big wheels with grippy low pressure tyres and good mudguards/flaps

Intermediate mud = Big wheels with fat a low pressure tyres with an open shallow tread and and good mudguards/flaps

Wet Heavy clay = Fat low pressure tyres and lots of tyre wall clearance

Sticky heavy clay = large diameter, thin low pressure tyres with an open shallow tread and at least 2" of tyre clearance

Ploughed soft soil = Fat low pressure tyres

Hard bumpy soil = Fat low pressure tyres (with suspension?)

Fine dry sand = Mega-fat low pressure tyres

Fine wet sand = Most large diameter tyres

Coarse sand = Very fat low pressure tyres

Shingle = Fat low pressure tyres

Deep gravel = Wide low pressure tyres

Shale = Fat low pressure tyres

Small pebbles = Very fat low pressure tyres

Large pebbles = Fat low pressure tyres

House brick style rocks = Fat low pressure tyres on narrow rims

Rough and hard rocky surfaces = Fat low pressure tyres

Smooth hard trails = Tacky high pressure tyres

With a Fatbike and a selection of alternative wheels and tyres you can efficiently ride all the above.

The first real all terrain bicycle? 8)


Top
 Profile  
 
 Post subject:
PostPosted: Fri Feb 24, 2012 10:17 pm 
retrobike rider / Gold Trader
retrobike rider / Gold Trader
User avatar

Joined: Tue Nov 03, 2009 10:00 pm
Posts: 5611
Location: Newcastle Upon Tyne
yeah, i prefer the name fatbike rather than snow bike......its north america and europe where the snow is around for months where they gain that name, but for me i use it for all terrain.

as for sand, these tires come into there own.....aslong as the tire is built for it and the pressure and gears are right.

im talking 5 psi here in these pics, this is the worst sand, near the water on a tidal basin, even a footprint sinks in about 2-3'' its that soft, almost like quicksand, the pugsley my girlfriend was riding was loads slower than on the rest of the beach, mainly because of the thicker, more spaced out surly nate 4.0'' tires.....you can see the deep tracks here.

Image

Image

eventually she gave up....notice the deep footprints and how much her feet have been under!

Image

notice my 4.7'' big fat larry tracks, same pressure but less rolling resistance due to the smaller knobs.

Image

here my girlfriend follows on the pugsley in my tracks, much easier when the wider tire flattens the path first.

Image

the smaller knobs dig in less, instead rolling rather than cutting along the sand, you can see it barely leaves a mark on normal sand...

Image

Image

4'' tire on 65mm rim on the left (pugsley) and 4.7'' tire on 100mm to the right from the moonlander...

Image


Top
 Profile  
 
 Post subject:
PostPosted: Fri Feb 24, 2012 10:51 pm 
retrobike rider
retrobike rider
User avatar

Joined: Tue Sep 30, 2008 6:25 pm
Posts: 924
Location: Near Wendover Bucks
I didn't mention quicksand because I have not ridden quicksand since 1984.
I had a bad experience when riding in the Mersey estuary when I had a large area of quicksand between myself and the shore. I ended up walking up to my knees in estuary mud whilst carrying my bike. Coastal exploration can be very dangerous if you fall foul of quicksand and quick moving tides. And people die every year.

Experience tells me that FatBikes will be best suited to riding sand, pebbles, soft soils and farmland and rough rocky surfaces. I find it strange that there are few stories of them riding rocky mountain trails. They could be excellent with the right gearing. I remember being amazed that my Cleland with its puny 2" wide low-pressure tyres could ride over a pike of dumped house bricks. Just imagine what a 4" wide tyre could manage.


Top
 Profile  
 
 Post subject:
PostPosted: Fri Feb 24, 2012 11:05 pm 
Retro Guru
User avatar

Joined: Fri Feb 26, 2010 11:41 am
Posts: 1090
Location: Calder Valley
The wheel set with tyres must weigh around 5kg, all that alloy and rubber?
Surely they don't run the standard 136 rear hub?


Top
 Profile  
 
 Post subject:
PostPosted: Fri Feb 24, 2012 11:11 pm 
retrobike rider / Gold Trader
retrobike rider / Gold Trader
User avatar

Joined: Tue Nov 03, 2009 10:00 pm
Posts: 5611
Location: Newcastle Upon Tyne
graham1975 wrote:
The wheel set with tyres must weigh around 5kg, all that alloy and rubber?
Surely they don't run the standard 136 rear hub?


yep, 135mm front and rear......interchangable, so you can have a rear wheel on the front as a spare :wink:


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 128 posts ]  Go to page Previous  1 ... 9, 10, 11, 12, 13  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 8 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

About Us

Follow Retrobike

Other cool stuff

All content © 2005-2015 Retrobike unless otherwise stated.
Cookies Policy.
bikedeals - the best bike deals in one place
FatCOGS - Fat Chance Owner's Group

Powered by phpBB® Forum Software © phpBB Group