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Discussion Starter #1 (Edited)
Hey all Pug lovers...

I'm back from my 2nd Simpson Desert Bike Challenge and I need some advice/help.

Both times I've run with my Ibis Mojo SL with different tyres and 28mm wide rims.

Now before you regail me with how I SHOULD have ridden a Pug'... hear me out.

1st... go to: www.desertchallenge.org/race_details.html ... it will tell you a little about the event.

It's a ride (race?) across the Simpson Desert in Australia. two stages per day. 80klm each morning, 50klm each afternoon. For 4 days, The 5th and last day is 80klm morning only. (but hey... you finish the stage at the Birdsville Hotel) Crossing many many sand dunes. Some are smaller and somewhat ridable... some are damn huge and very very soft.

The problem comes in the sections between the dunes. Sometimes the terrain is corrogated and hard. Sometimes it's corrogated and hard... and covered in 4-8" of very soft sand. Sometimes when running parralel to the dunes (between them)... you get long stretches of soft deep sand. Sometimes it's hard saltlake/claypans...

All these variables lead me to use the Mojo with 2.5" wide tyres in 2008 and 2.2" wide ravens (run very soft) this year.

Last year... it worked ok. I was able to ride the sand... mostly... (well... ok... a little...)

This year... oh dear... the sand was soft, Very very soft... and I did much walking. Much to the horror of my legs. I can ride for days no problem. But walking is bad for me...

My questions are this:

a) How much floatation does the Endomorph have on very soft, hot sand at max inflation? I mean... could I run it 'hard" (you know... Endomorph hard... soft by any other tyres standards)... and still ride on top of the sand? Or will I need to run the tyres soft(ish) to get decent floatation?

b) how much drag does the Endomorph have on hardack? This year I pumped my Ravens up from 15psi to 30+ when I hit a 30klm stretch of salt-lake...

c) anyone running Large Marges and Endomorphs tubeless? (anyone NOT running Stan's in the desert this year got punctures from the thorns)

I guess I'm trying to balance the drag of the larger tyres v's the advantages of floatation over the sand...

I feel that if I can stay on the bike riding... I'm mentally better off. if I have to walk... then I get very negative. Then my speed drops. Once you get below 12.5 kph... the sweep 4wd picks you up...

Help appreciated.

And before someone says the obvious... "build one up"... I'd like some honest feedback 1st.

Thanks in advance guys.

Elvis.
 

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is buachail foighneach me
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A: maybe a little bit more than a normal tire at super soft inflation. from what i've seen, you lose alot of stability in soft stuff at 30+ psi with endos.

B: not much rolling resistance, but alot more weight. they will be slower than the ravens, but you'll be able to ride ALOT more than the ravens would let you do.

C: yes, there's a thread or two on the subject here. apparently a bit of a pain to set up tubeless. you could always put the stans in the tubes.

this is all theory and conjecture, as i don't own a bike with endos. kinda makes you wonder why i would even bother answering, doesn't it?
 

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Elvis - the endos will give you a great deal more float that what you are running, even with max pressure. They also have more rolling resistance than a lot of tires - but maybe not so different, or worse, than a full-on knobby on pavement. Some folks run their fatbikes on endos year round and they seem to do fine. So, my guess is that you would do a lot less walking with endos, you won't set any speed records on the hard surfaces and you will have a lot of fun.
 

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I was amazed at how little the Endo seemed to slow a bike down on hardpack and pavement last year - I rode a Jones with the Fat Front and 2.55 WW LT on the rear. The big tire on front rode fine, hardly seemed to slow me down at all. Took a little getting used to in the rockier technical stuff that I hit later in the ride, but some of that was just likely getting used to the tire and the way the big air volume rebounded off of things. I would bet that the speed gained on the sandy sections with the Endo at even "normal" softer pressures would far outweigh the slow, high-effort miles in the sand on a smaller tire, even with low pressure. I rode a lot of sand over the years in the deserts outside of San Diego, and the biggest tires we ever had were the Ritchey 2.35 Z-Max. When it got really soft, we were walking, and I am a pretty good sand rider. I see photos and vids of people riding some very squishy-looking sand and mud with Endos that I am sure would be walking with just about anything on a "normal" sized tire and rim. I wonder how the Endo/29'er rear combo might work with a fatter 29" tire - they are starting to land now... The bigger diameter works great in sand. On the Hut-to-Hut trip 2 years ago, we hit a mile or so of DEEP sand descent, I had a heavily loaded bike (29'er rigid) and just blazed through the sand - put about 4 or 5 minutes on my buddy on his lightly-loaded 5" travel 26" bike in that mile or so. I've been wanting a Pug, but don't have sandy stuff or snow here to ride on.
 

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Witty McWitterson
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A] Not really sure. I've only ridden mine on packed/loose snow, and at low pressures it worked much better than with higher pressures.

B]Surprisingly, not as much as you'd expect. This tire is SO much more sensitive to pressure than any other tire I've ridden its not even funny. It seems as if there's a two to five psi sweet spot for hardpack. I did a race on mine this spring that utterly surprised me in how well it performed. Of course, comparing the Endo to a Raven is asking for trouble.

C]I've tried and failed the tubless thing. I know of a local that had a successful conversion when he lived in TX. Since I failed, I simply took out the core of the tube I was using and put in some stans. Ghetto, and it worked.
 

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Elvis, I've considered doing the Simpson Challange and would consider nothing but a fattie. I've ridden a mates Pugs over all sorts of terrain and don't understand why the guys haven't changed over to them for the Simpson. I've also got another trick up my sleeve....I purchased a Christini AWD frame which arrived the other day. I'm going to do a mod on the front fork to take an Endo......watch this space..... Al
 

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Discussion Starter #8
alanm said:
Elvis, I've considered doing the Simpson Challange and would consider nothing but a fattie. I've ridden a mates Pugs over all sorts of terrain and don't understand why the guys haven't changed over to them for the Simpson. I've also got another trick up my sleeve....I purchased a Christini AWD frame which arrived the other day. I'm going to do a mod on the front fork to take an Endo......watch this space..... Al
Which is where I'm at now. (thanks to the feedback above)

I'll build a Pug' as soon as I sell the Mojo.

Build will have Mr Whirly cranks and a Race Face cockpit w/Cane Creek suspension seatpost.

A few of this years Simpson Desert riders spoke of Pugs' for 2010. I'll get a flyer to them.

Good luck with the AWD concept.

Elvis.
 

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Discussion Starter #10

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Hi Elvis. Russ here. I rode through the Simpson (French line and QAA track) a little earlier this year as a fund-raiser for the RFDS. The Simpson was the last of my ten deserts ride: 10 Deserts it's friggin amazing out there. I've never felt so alive in my life. From the intersection of the French line and rig road, I also got an appreciation of what the rig road was like ... very easy by comparison.

The Endomorph's are terrific. There is very little loss of speed on the harder-pack terrain given what you'd conceive as extra drag. The 4" hoofs significantly make up in what they offer in float in soft sand, horrendous corrugations and gibbers for what you lose in top end speed on hard-pack.

By comparison, I can comfortably average 100+km/day (up to 240km off-road one day) during a 3 month continuous ride on a fully loaded bike/trailer on these fat hoofs. There's no way I could do this on even 2.5" tyres.

Great balance too. Cresting the cornice of some extremely soft dunes, I'd be down to 3.5km/hr, but still "just" able to keep the front wheel down.



Fat bikes are amazing for where they can take you, and I can highly recommend the Fatback. Let the adventure begin - hehe:)

These photos are of some local trials:



More here: https://russellworthington.blogspot.com/
 

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Discussion Starter #12 (Edited)
AdventuRUSS said:
Hi Elvis. Russ here. I rode through the Simpson (French line and QAA track) a little earlier this year as a fund-raiser for the RFDS.
hey Russ'

I was about to email you directly. I figured if anyone could understand exactly what I wanted it would be you!!!

The race this year ran across the QAA line from the K1 just south of Poepell Corner then across the salt lake onto the QAA line then on to Big Red.

Usually we take the Rig Road across to the K1 then down to Warbuton crossing. (then up the Birdsville track to the Inside Track) But Warbuton Crossing was closed due to rain so up to the QAA we went.

I didn't realise that you rode the French Line. Now THAT is soft! Or very very hard (core)...

Thanks for all your advice and suggestions. You have more than answered all my questions. (though I may still email you... is that ok?)

And in case everyone else forgets to mention it... bloody amazing effort. :thumbsup:

Elvis.
 

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sand pressure

A) You'll get a little more floatation at max. but only from footprint. They'll still "saw" into the soft sand. You've got to let some (or alot) air out to get the full benefit of this set-up. I've ridden alot of soft sand - even on the old Snow-cats - and good floatation depends on three main ingrediants: the widest rims your frame can handle; the biggest (most plyable) tire you can fit; and most of all running the lowest pressure you can handle ( relative to the consistancy of the sand of coarse ) In the Oregon Dunes last July I ran just under 4 lbs in the front and 5 lbs in the rear tire in the open dunes and a couple pounds more out on the beach.

A+B) Martini's got it right on the money - these things are very pressure sensitive! On hard pack & rocky surfaces even half a pound can make a big differance. And, contrary to their appearance, they do not take a long time to adjust. They might have alot of volume but the pressures are so much lower than reg. tires ( these things are plenty hard at 20 lbs) that it evens things out. In fact, I'm always amazed at how little time it takes to pump 'em back up. Especially with a good pump (I currently use a Lezyne - best pump I've ever had!!) As far as drag goes you've got more surface area touching the ground so theres gonna be drag...but the Endo's design reduces some of it (especially at higher pressures) and once you build some speed they carry momentum like a freight train. In my opinion, if you can spare a little time to adjust your pressure (for the longer sections anyway) you'll be ahead in the long run.

C) haven't messed around with a tubeless set-up on these yet...I'm sure thinking about it though! Most ATV's and other high-floatation vehicles do run tubeless. Is anyone runnin' tubeless at soft sand pressures? And, how's it working?

Good luck on your adventures!!
keep the round side down!!

- Ward
 

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ward said:
A) You'll get a little more floatation at max. but only from footprint. They'll still "saw" into the soft sand. You've got to let some (or alot) air out to get the full benefit of this set-up. I've ridden alot of soft sand - even on the old Snow-cats - and good floatation depends on three main ingrediants: the widest rims your frame can handle; the biggest (most plyable) tire you can fit; and most of all running the lowest pressure you can handle ( relative to the consistancy of the sand of coarse ) In the Oregon Dunes last July I ran just under 4 lbs in the front and 5 lbs in the rear tire in the open dunes and a couple pounds more out on the beach.

A+B) Martini's got it right on the money - these things are very pressure sensitive! On hard pack & rocky surfaces even half a pound can make a big differance. And, contrary to their appearance, they do not take a long time to adjust. They might have alot of volume but the pressures are so much lower than reg. tires ( these things are plenty hard at 20 lbs) that it evens things out. In fact, I'm always amazed at how little time it takes to pump 'em back up. Especially with a good pump (I currently use a Lezyne - best pump I've ever had!!) As far as drag goes you've got more surface area touching the ground so theres gonna be drag...but the Endo's design reduces some of it (especially at higher pressures) and once you build some speed they carry momentum like a freight train. In my opinion, if you can spare a little time to adjust your pressure (for the longer sections anyway) you'll be ahead in the long run.

C) haven't messed around with a tubeless set-up on these yet...I'm sure thinking about it though! Most ATV's and other high-floatation vehicles do run tubeless. Is anyone runnin' tubeless at soft sand pressures? And, how's it working?

Good luck on your adventures!!
keep the round side down!!

- Ward
:thumbsup: DITTO.
 

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hispanic mechanic
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ward said:
*snip* Is anyone runnin' tubeless at soft sand pressures? And, how's it working?

Good luck on your adventures!!
keep the round side down!!

- Ward
I'm working on a tubeless-fication right now. Had my compressor go out on me (bad shut-off switch) but hope to get them aired up today. I'll definitely post my results, and plan on playing with pressures for sure.

Los
 

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You can still ride pretty quick. The bike is not so great for snappy switchbacks etc, as the tyre has such a wide contact patch under cornering that it just feels like it wants to keep going straight. I rode one in a 24hr race and it was fine. I think that the extra weight of the tyre (a lot!) keeps momentum up whel you freewheel, and the relative lack of tread helps to keep them rolling with not too much resistance.
 

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I've been running basically 8 psi front and 10 rear all year round. Rock gardens and technical become easy pickins, only drawback is you "feel" the contact on the tarmac, that big of a contact patch leads to resistance.
 

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Sand and Snow, this rig really shines. and leaves the skinny crowd standing in awe.
 

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Hi Elvis,
I know your questions already been answered there, but just wanted to add that im one of those idiots riding a pugsley as a daily commuter (even though i have a custom reba 29er i spent a small fortune on, it doesnt even get considered anymore)... my point really is that as mentioned above the pugs is extremely sensitive to pressures, the compound of the rubber allows the contact patch to be adjusted in amazing ways. i dont ride mine extremely hard (psi wise!) and find it just as fast as any mountain bike, seriously with an alfine on the rear this thing mashes, and handles beautifully on pavement, im not sure where this thing about them handling badly ever came from? For me it was a matter of getting used to for about 30mins to an hour, then it became second nature and addiction! i cant go back now, i will always ride my pugsley. as far as sand is concerned (im sure coast kid can chime in here too) i do a fair bit of beach riding, and although its not as soft and as deep as what you are asking about due to the moisture content here, im comparing to hardpack with a 3-6inch soft cover, i dont even need to adjust gear from the road to this- just trust that the pugs is fast!

It WILL puncture easy, these rubbers are SOFT, i have a couple chunks missing myself from just day to day mayhem, i would run stans in the tubes, in fact im going to myself as of today!

good luck Elvis!
 
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