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Front tire and steering response

12K views 48 replies 25 participants last post by  rmac 
#1 ·
New to fat bikes. Been riding a pugsley for a couple of weeks.

This might be helpful to other newbies. Bike came with a pair of endomorph tires. Front wheel steering had a pulling sensation when you initiated a turn or at times when the trail is a little off camber. I was running tire pressures of 8 to 10 psi.

To day I changed the front tire to a surly Larry. Wow the tire has hardly any pulling sensation. Very please. Will leave the endomorph on the rear.

So what other tires make for good steering tire?
 
#2 ·
I eventually transitioned to Surly Nate tires from the Larry/Endomorph front/rear combination. Now the bike traverses surgically through the corners when the conditions are loose/muddy/rocky/off-camber/etc. as if it were on rails. If you can stand a bit more rolling resistance (It will just make you a STRONGER rider afterall!) then I highly recommend the upgrade.
 
#20 ·
I agree. I had commented in another thread about the self-steer on my Pugs. I just put some Nates on this week and have to say that it was the best thing I could have done. I am in love with a fat man named Nate. Has taken care of the self-steer feeling altogether and I had a heck of a time breaking lose on anything while out on the trails the last couple of days.

Go with the Nates. It feels good to be in love.
 
G
#7 ·
New to fat bikes. Been riding a pugsley for a couple of weeks.

This might be helpful to other newbies. Bike came with a pair of endomorph tires. Front wheel steering had a pulling sensation when you initiated a turn or at times when the trail is a little off camber. I was running tire pressures of 8 to 10 psi.

To day I changed the front tire to a surly Larry. Wow the tire has hardly any pulling sensation. Very please. Will leave the endomorph on the rear.
The self steer is normal for the offset pug regardless of tire choice. I can't quantify if it happens more / less with a particular tire though.
 
#9 ·
Self Steer

The Pugsley offset front fork has nothing to do with the self steer tendency. I have a Pugsley with dual Larry's on it. I have run a stock offset fork with a stock offset wheel, a Salsa Enabler fork with a centered wheel and now, a centered Pugsley fork with centered wheel. All three forks have the same rake offset 43 mm, but axle to crown is different which affects head angle and crown. The Enabler ( taller A-C) slacked out the head angle to 69 degrees and I did not like the wheel flop and wandering I experienced during steep or technical hill climbs. So, I went to a centered Pugs fork with the centered front wheel to return the geometry to stock head angle and trail.

I converted my pugs to a centered front wheel to allow good handling with 29'er wheels in the summer.

If you are interested, do some research on Jeff Jones and / or On-One fat front forks. They both make forks with 55 mm rake that will reduce the front end trail. This should reduce the self steer. I think the big tires need less trail than standard 2" wide 26 or 29er tires and Mr. Jones is on to something. I really want to try a 55 mm rake fork with a stock A-C on my Pugs.
 
#18 ·
Jones Truss Fork

The Pugsley offset front fork has nothing to do with the self steer tendency. I have a Pugsley with dual Larry's on it. I have run a stock offset fork with a stock offset wheel, a Salsa Enabler fork with a centered wheel and now, a centered Pugsley fork with centered wheel. All three forks have the same rake offset 43 mm, but axle to crown is different which affects head angle and crown. The Enabler ( taller A-C) slacked out the head angle to 69 degrees and I did not like the wheel flop and wandering I experienced during steep or technical hill climbs. So, I went to a centered Pugs fork with the centered front wheel to return the geometry to stock head angle and trail.

I converted my pugs to a centered front wheel to allow good handling with 29'er wheels in the summer.

If you are interested, do some research on Jeff Jones and / or On-One fat front forks. They both make forks with 55 mm rake that will reduce the front end trail. This should reduce the self steer. I think the big tires need less trail than standard 2" wide 26 or 29er tires and Mr. Jones is on to something. I really want to try a 55 mm rake fork with a stock A-C on my Pugs.
I have a Jones truss fork on my Pugs and it steers and handles way better than the stock Pugs fork.
 
#11 ·
Nope, offset fork or wheel has nothing to do with it. Let's put that rumor to bed right away. :thumbsup:

The Endo in particular has a very square profile, hence the draggy feeling when steering. Larry et al are much rounder, so no, or greatly reduced self steering.

Run any of the tires low enough, and they will start to display the characteristic though.
 
G
#12 ·
Nope, offset fork or wheel has nothing to do with it. Let's put that rumor to bed right away. :thumbsup:

The Endo in particular has a very square profile, hence the draggy feeling when steering. Larry et al are much rounder, so no, or greatly reduced self steering.

Run any of the tires low enough, and they will start to display the characteristic though.
this does not explain why mine does it. I started with 10psi both ends and it behaved this way and now that i'm @ 7psi both it is more pronounced.
 
#13 ·
NVPHATTY,

You have a beautiful bike. I like the color scheme alot.

My experience with self steering, is a tendency in loose dirt or hardpack, when carving single track at moderate speeds, for the bike to want to oversteer, to turn itself, more into the turn. It is kind of like, you turn the bars, or lean the bike, and then you have to resist the bars as the bike tries to spiral steer itself even tighter into the corner. Weird. Seemed worse with the Enabler. (Which kind of chopper-ed my bike out.) I do not notice this phenomena in snow. Feels the same left or right.

Engineering moment - Warning - (Stop reading if you do not want to fall asleep)
If you examine your bike from above or behind, the centerline of the rim/tire is (should be) in line with the centerline of the bike itself. Even though the centerline of the rim/tire is 17.5 mm offset from the hub(s) centerline. There is no engineering reason for the bike to react differently with the ground, when leaned left or right.

Now, maybe there is some wheel flex, that ruins my explanation. Or maybe the the vertical force vector of the rim which is misaligned by 17.5 mm with the center line of the hub is creating some wierd torsion in the frame. But, if there is some strange phenomena, causing what you describe, than it should manifest itself in lefty forks in a big way and some of the high end motorcycles that use one sided swing arms in the rear.

Just my opinion, please accept it with a large grain of salt. ;)
 
G
#14 ·
NVPHATTY,

You have a beautiful bike. I like the color scheme alot.

My experience with self steering, is a tendency in loose dirt or hardpack, when carving single track at moderate speeds, for the bike to want to oversteer, to turn itself, more into the turn. It is kind of like, you turn the bars, or lean the bike, and then you have to resist the bars as the bike tries to spiral steer itself even tighter into the corner. Weird. Seemed worse with the Enabler. (Which kind of chopper-ed my bike out.) I do not notice this phenomena in snow. Feels the same left or right.

Engineering moment - Warning - (Stop reading if you do not want to fall asleep)
If you examine your bike from above or behind, the centerline of the rim/tire is (should be) in line with the centerline of the bike itself. Even though the centerline of the rim/tire is 17.5 mm offset from the hub(s) centerline. There is no engineering reason for the bike to react differently with the ground, when leaned left or right.

Now, maybe there is some wheel flex, that ruins my explanation. Or maybe the the vertical force vector of the rim which is misaligned by 17.5 mm with the center line of the hub is creating some wierd torsion in the frame. But, if there is some strange phenomena, causing what you describe, than it should manifest itself in lefty forks in a big way and some of the high end motorcycles that use one sided swing arms in the rear.

Just my opinion, please accept it with a large grain of salt. ;)
thank you

Everything is aligned, ie wheels, frame etc and while i lack the knowledge to ascertain the reason I appreciate ramblings and make as much sense of them as humanly possible. ;)
 
#15 ·
Having not spent any time on the Origin 8 tires, I'll toss them out as a possibility.

Endo does it like mad. Larry does, only when pressure is too low.

Running three fatties. Offset fork Pug with a BFL offset built Rolling Darryl, no issues. Demo Pug at the shop, 100 mm symmetrical fork with symmetrically built CUS Hundie and a Nate, no issues. Lefty on my Form with a Uma 90 built offset and a Bud, no issues either.

Tried a different tire yet?
 
#31 ·
IME, its the Origin 8 Devastators.... more below

Having not spent any time on the Origin 8 tires, I'll toss them out as a possibility.

Endo does it like mad. Larry does, only when pressure is too low.

Running three fatties. Offset fork Pug with a BFL offset built Rolling Darryl, no issues. Demo Pug at the shop, 100 mm symmetrical fork with symmetrically built CUS Hundie and a Nate, no issues. Lefty on my Form with a Uma 90 built offset and a Bud, no issues either.

Tried a different tire yet?
Have to agree with Mendon. My friend and I both bought 907s last year that came equipped with Nates. Awesome tires. Decided we wouldn't need as much traction for the summer and purchased the $45 Devastators with a Kevlar casing. We noticed the self steering feel immediately and it is worsened with low tire pressures. For myself, I ended up running the Origin 8s at 10psi front and rear at a bodyweight of 240lbs. Running lower psi worked better for ride quality but the self steering was noticeable.

Otherwise, they are an awesome tire and after a few rides we both adjusted to it at the higher pressures. It really depends on the trail as well. One system that we like to go on has a few trails with severe erosion from rain run off and the self steering was wicked on those trails. I believe the tread design somehow "locks on" to the off camber ruts and "follows the rut".

Note that I had switched back to the the Nates in September and the better quality steering was immediately noticeable. I still like the Origin 8s, particularly for their puncture resistance. I rode through the summer with no flats and have already had four flats after switching back to the Nates in Sept.

Also, I have never owned an Endo but have seen them on other bikes and on the web etc. The Devastator tread design resembles an endo with a "broken" tread pattern. Myself, I am hoping that Origin 8 puts out a knobby styled Devastator with the Kevlar casing. I was actually riding through overgrown thorny areas to test them and never got a puncture. Only downside, they are heavy. I believe some sites list them as 2000 and as high as 2100 grams and I believe it!!!
 
#16 ·
My Moonlander with Clown Shoes + BFLs front and rear "self-steers" at low pressures. When turning or just leaning the bike to either side while riding, the tire seems to make it turn further.

All bikes will self-steer somewhat when leaning (we actually need it to do this so we can steer when riding without hands on the bars), but only with a fat bike I need to actively keep the handlebar from turning too far.

The fork is symmetric and the effect is similar on both sides, so it can't be an issue with offset.
 
#19 ·
Those Origin8 tires are made by vee rubber who also has their own fat tire called "mission" which I have and which "self steers" way more than a larry. Could it be in the construction of the tire, not just tread pattern? I have a centered fork but logically an offset fork shouldnt have anything to do with it. I'd love to try a more raked fork.
 
#21 ·
Until I switched to Husker Du and Nate, I never even for a second could pedal without my hands on the bars. Now it's so easy to steer I often pedal one handed for extended periods and even let go on pavement. I may be a wuss, but Devist8er's never offered me that level of trust.

Many people have mentioned Nate on the front, but in the soft stuff it's doing great on the rear. Husker Du on the front feels really safe like the bike is on rails even in packed snow.
 
#22 ·
I put the Devist8or tire on last week, and it seems to devistate the steering of my offset (stock) Pugz. It's a really round tire in profile, so i wondered if that made an impact. My Larry did not steer like this, it was very predictable. After the Holiday Madness is complete, I may switch it with the Nate currently on the rear. It felt to me like it wanted to grab and pull to the left on pavement or frozen dirt, and if I steer left in snow, it tracks OK, then suddenly spirals to the left. It also weighs nearly 5lbs, so I'm sure I'll be really strong by springtime.
 
#23 ·
IF your trails get icy, keep it even if you get another tire, Devist8er should be tough enough to stud it. First, drill pilot holes through the center of a tread block. Then take Pan head sheet metal screws or "self tapping" screws and screw them from the inside outwards. An ice racing buddy suggested this, he did it for lake racing on dirt bikes and cars.
 
#26 ·
If your Pug has different steering characteristics from one side to the other, the most likely reason is that the back wheel is not aligned properly with the front, ie it is squint in the dropouts.

(assuming your frame is properly aligned)
 
G
#30 ·
not my case. front is bottomed in the fork drops, the rear is all the way forward in the hor drops for the shortest wheelbase. IF in fact the 2 wheels are not tracking inline then perhaps the frame is misaligned. Frame was chased/faced with only the paint removed from surfaces to ensure it was square before assem. nothing amiss with headset install or it's setup, ie it rotates freely in both directions and does not rock within the steer tube.
 
#27 ·
Carcass shape is the reason the Endo displays the self steer it does, and the reason the others in Surly's line up, don't.

Sounds like others are saying they experience what you do with those Origin8 tires. Having not been on them myself, I can't say, but I'm guessing they are flatter in profile, which will make them drag you all over the place, not fun.

I have an old Larry I'd be happy to ship you cheap if you want to try out the theory.
 
#29 ·
Big thank you to everyone for the good discussion on this thread. I have struggled with the self steer issue during the summer and this winter I have been struggling with traction in the snow. I am waiting for the Devist8er that I have ordered for the rear of my bike. I am not sure what I could put on the front. I am leaning towards a nate, but they are kind of expensive. Now I am wondering if the devist8er might self steer more than my Larry does? (during the summer)
 
#33 ·
nvphatty,

Something else that hasn't been mentioned yet. If the tire being used has a self-steering tendency, there could be a left vs. right difference in feel based on human bias to the left vs. right. You might never see it on a narrower tire bike, but with the fat low pressure tires that have a lot more pull it may be accentuated. Some people are just more comfortable with going one direction over the other. Just something to throw out there.
 
#43 ·
I like to say "with a nate, take it down to eight" (more)



but "nine is fine" also. In short, for a trail that I am not familiar with I will usually run 10psi front and rear to keep things simple. I don't mind stopping multiple times to take the pressure down by hand and then measuring it during a rest break (If one of us remembered to bring a gauge) or sometimes not until the end of the ride. The amazing part about these bikes is the effect that a pound of air can have upon the ride quality. Be sure to get a gauge such as the Meisers 0-30 psi so that you get a consistent reading. I had planned to purchase a higher end digital gauge but never got around to it.

In snow, different story. Lower pressures. On Sunday, I ended up down at 5psi which was a bit of mind game for me since this was the first snow for us this season in NEPA. No need to over complicate things. If you end up riding an area that seems too soft for the bike just remember to let air out before giving up on it. A pound of air can literally lead to riding over walking a section.

BTW, I forgot to mention about the Origin 8 profile vs. Nates. The Origin 8 has a very flat or squared off carcass compared to the round profile of the Nates. I'm sure Mendon is right about that being the cause of the self steering response. Actually the Origin 8s would probably be perfect for the snow we have now (dry powder) but we usually get a heavy wet snow or get rain a few days after a storm which is one of the reasons the Nates have performed well in the past.

The tire carcass shape/profile is an interesting issue for me. I have heard on this forum that some people were not happy with the Moonlander on single track (of course, others have raved about it) and I wonder if it was the tires or the 100mm clown shoes (or both) creating more a wide stanced tire on the trails. I've been interested in the Moony since they came out but have never had the opportunity to ride one and have never seen one in person yet. Conversely, I sometimes wonder if Surly got it right the first time with the Pugs.

My friend and I had talked about running the devastators backwards but never got around to it. I had meant to try running the Nate backwards this winter but have been too lazy to change the tire again!!
 
#35 ·
In reading several of the responses here, it seems that tread pattern is something folks consider to be a factor.

While we refer to a given tire, which obviously has a pattern, it's not the pattern that is affecting the issue at hand.

Carcass shape, tire profile, casing shape, whatever you want to call it, is.

Anyone who's tried an Endomorph up front and switched to another tire like a Larry or Nate, knows exactly what I'm talking about.

I have no time on the Origin8 tires, so I can't speak to them personally, but forward or backward, if folks are getting self steering with them at reasonable pressures, they suffer from the same issue as Endo's, a square profile.

Now this isn't a bad thing. The OG of our little club all loved the Endo for it's superior flotation qualities. The squarer profile gives a nice flat contact patch, less prone to diving into soft, packed powder. So, extrapolating from there, the one thing that sucked about the Endo was traction, either drive, or steering.

So if the O8 tires have a similar squarer profile, and more bite, they are a win (weight notwithstanding) for the snow floater crowd.

:cool:
 
#40 ·
In reading several of the responses here, it seems that tread pattern is something folks consider to be a factor.

While we refer to a given tire, which obviously has a pattern, it's not the pattern that is affecting the issue at hand.

Carcass shape, tire profile, casing shape, whatever you want to call it, is.

Anyone who's tried an Endomorph up front and switched to another tire like a Larry or Nate, knows exactly what I'm talking about.

I have no time on the Origin8 tires, so I can't speak to them personally, but forward or backward, if folks are getting self steering with them at reasonable pressures, they suffer from the same issue as Endo's, a square profile.

Now this isn't a bad thing. The OG of our little club all loved the Endo for it's superior flotation qualities. The squarer profile gives a nice flat contact patch, less prone to diving into soft, packed powder. So, extrapolating from there, the one thing that sucked about the Endo was traction, either drive, or steering.

So if the O8 tires have a similar squarer profile, and more bite, they are a win (weight notwithstanding) for the snow floater crowd.

:cool:
Couldn't agree more and what makes the endos and other square profile tires so bad on hardpack is exactly what makes them so great on snow and loose sand- that square cross section equals floatation. I think it was Pete Bassinger several years back who explained it so well and explained why the square cross section doesn't want to jack knife on snow like a rounded or narrow tire. An endo up front is horrid on most conditions but they excel in sand and snow. I wish they would have a BFE or at least not discontinue that tire.
 
#44 ·
I am pretty sure that it is the tires. The roundness and width of the tire allows the outside treads to come into contact with the surface, especially when running low pressures on a hard surface. As the outside treads contact the riding surface they will pull the tire that direction. Try riding along a rounded gutter curb, it almost pulls you up the curb. I agree some tires are much better than others, I haven't tried endo's in front but nates are much better than larrys.
 
#48 ·
What have folks been running their HuDu's at? I am guessing mine are at 8-12psi up front and 6-10 in the back one.
Currently running the HuDu in somewhat compacted snow by snowmobile, skis and snowshoers in these temps of -1 to -5c. They have been incredibly forgiving on fast corners with the front end just starting to wash out at times. Seems for the most part, an intuitive counter steer (using Jeff Jones Loop bar) is all the Bear needs and the bike pulls out of what might be a disastrous crash in the making! So far I have only gone airborne over the bars once as I got pulled into a deeper rut with unpacked snow :)
My LBS is looking thru their stuff to find one of the small brass low pressure presta gauges that I saw online recently.
 
#49 ·
I started out with Larrys front and back on my Fatback. Switched to Nate on the rear early last winter and put a second Nate on the front this winter.

Really struggled with off-camber fresh snow traction on the front with the Larry – slides out very quickly. The Nate on the front is much better in these conditions but still slides out (not sure it is reasonable to expect any tire to grip off camber freshies? Would love to see a front tire review for these conditions with all tires). The front Nate doesn’t ‘flow’ as well downhill as the Larry though (in fresh snow) – it almost grips too well and where the Larry will roll the Nate will sometimes ‘grip and slip’.

My favorite fat bike conditions are heavy crust snow, untouched snow where the top has melted and refrozen – here the Larrys excel, The Nates knobs tend to break through the frozen top where the Larrys grip and go. Tscheezy made a video of these conditions a while ago on Alaska.
 
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