Bigger tire in front?

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craneplaneguy   10 kW

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Bigger tire in front?

Post by craneplaneguy » Jan 01 2019 7:29pm

I have heard of some using a smaller tire in the rear, to get a better gear ratio, but I am considering going with a 2.5 or 2.75" front tire (26") on my eMontague to make it a better trail bike. Right now I have 2" tires, on a 22 mm rim. I would, I am told anyway, have to get a larger rim to take full advantage of the larger tire. While I am at it, I want to go tubeless on the front. This is all because I use the Montague for trail riding, when on a trip, when local I use my efattie. A fatter tire (I can fit up a 3" in the Sun Tour fork) on a rough trail will offer a smoother ride and maybe better directional control, but more drag on pavement. And pavement riding is important, I do a lot of that with it also. So right now I am thinking of just an increase to 2.5", along with a new rim that will lend itself to running a tubeless configeration. Anyone else go this route? No room on the rear, so it will stay as is.

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Re: Bigger tire in front?

Post by markz » Jan 01 2019 9:19pm

Buy some "Thorn Proof" tubes, and a decent tire like the Schwalbe Marathon series if the knobs suit your riding. How does one fix a flat with tubeless, I prefer to carry a flat repair kit and a tube. Tubeless is too much hassle, too much work.

Montague's are great folding bicycles, I would buy one if I needed on. Since you can use a wider 3" fork, I would go for a 2.5 or a 2.8 if there is such a creature. Just enough leeway just in case, 2.80. More air, more cushioning.

Be careful that your fork will be able to fit your tire, and that your tire is the right size for your rim width.
Bicycle - Sheldon Browns website, near the bottom - https://sheldonbrown.com/tire-sizing.html





I am in the same boat as you, looking for a new front setup.
I got 4 flats today, still dont know whats going on.

I've been pondering going to motorcycle rims. I plan to go from a 26" x 2.10 tire and rim combo to a motorcycle width of WM1 1.60" and probably 19" which would make it 24" and my bicycle hub would need to be disc and 12G which I have in front of me now. I could go to a 21" motorcycle rim, which would make it 28" bicycle sizing. Either way I need to make up an adapter plate and I think going larger would help a lot. My side goal, when I find a fork, is to go fat tire setup, have to weld something up. But first things first, front wheel.

Do you get many flats?

I get too many, and I just ride smooth stuff.

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Re: Bigger tire in front?

Post by lionman » Jan 01 2019 9:29pm

You wont need a new rim. 2.5" tyre will run fine on a 22c rim as long as they have a standard clincher bead.

The profile of the tyre will be different than on a wider rim and the side walls will bulge more. Not sure what impact this will have on performance or longevity but 2.5" on 22c is within spec of all manufactures recommendations that I have seen.

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Re: Bigger tire in front?

Post by craneplaneguy » Jan 01 2019 11:24pm

Thanks for that info, that seems to be the prevailing wisdom, while at the same time many were telling me I had to go to a new rim. It will be simple enough to buy a larger tire and try it, if need be I can always go with a larger rim if need be.

It's simple math I guess, (insert pie symbol here) but a slightly larger tire holds a LOT more air, so worth pursuing. When screwing around with the bike in the plane, I never know where I'll end up. I have ridden it up to 9,000' two or three times, easy enough to do in Idaho and Montana. I hear that when you have a flat while tubeless, the backup plan is to carry a tube! I've had great luck with the fatbike since going tubeless. Most of my Montague problems are from trying to run too low of pressure in those narrow tires, my bad, but I do carry a tube plus a patch kit. In 2000 miles, maybe 3 or 4 flats, 5 or 6, something like that, so not too bad a problem I guess.

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Re: Bigger tire in front?

Post by 2old » Jan 01 2019 11:39pm

The larger width tire will have a slightly more rounded profile, but as others have said, should be fine. I've needed to repair tubeless flats where the sidewall was ripped slightly and the sealant was ineffective in closing the gap. A tube works fine, but it's important to remove all the sealant or the tube is difficult to keep in the tire when you're inflating it.

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Re: Bigger tire in front?

Post by Smoke » Jan 02 2019 12:34am

I saw some YouTube videos of a tubeless BMX setup and they seemed to be able to do some pretty silly BMX stunts and never do more than burp the tire. If that is the worst you have to deal with, just bring a pump.

Also, the setup they used was a 16" tube installed (partially inflated) on a 20" rim and then sliced to turn the tube in to a rim liner/valve stem. The rest was a decent wire bead 20" tire (not tubeless specific) and a bit of tubeless sealant. It's dead simple and the parts can be found nearly anywhere. The only issue seems to be initially seating the bead on the rim which requires a high volume air source, typically an air compressor.

I want to try it with a 20" tube on a 26" rim but I'll be doing mostly pavement riding so probably less than 2.5" tire width.

If I was traveling in an area where an irreparable flat could be a disaster, I would probably pack a couple spare tubes, a folding tire and extra sealant. With the innertube liner tubeless setup, once you remove the tire and liner, there won't be more than a tiny trace of sealant left on the rim so going back to a tube should be as easy as any tube/tire change.

When I'm commuting in my fairly urban setting I will bring a pump to refill after any burps and I'll take my chances with punctures too big for sealant because the Bus, Uber or calling a friend will make an unsealed puncture in to a major inconvenience rather than a disaster.
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Re: Bigger tire in front?

Post by E-HP » Jan 02 2019 1:03am

markz wrote:
Jan 01 2019 9:19pm
Buy some "Thorn Proof" tubes, and a decent tire like the Schwalbe Marathon series if the knobs suit your riding. How does one fix a flat with tubeless, I prefer to carry a flat repair kit and a tube. Tubeless is too much hassle, too much work.

Do you get many flats?

I get too many, and I just ride smooth stuff.
I watched this video and after seeing the 6mm screwdriver test, switched to tubeless.

https://www.youtube.com/watch?v=G2OqwuhNGfg

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Re: Bigger tire in front?

Post by flat tire » Jan 02 2019 1:26am

I've got 26" 2.3 Nevegal Elite on my downhill 4kw right now F/R. Unless you are regularly on the edge of traction it really doesn't matter what size you have or whether they're fat, skinny, hard, soft, etc. Now some human-power MTBers like a smaller tire on the rear because they think they can slide it around more easily. In general I find a setup that has equal tires on both ends is the most predictable and consistent.

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Re: Bigger tire in front?

Post by dogman dan » Jan 02 2019 7:26am

At one point I had a bike with 2.8 inch wide tires on both wheels. I did not like the ride, but this is in sand, or other dry loose dirt type conditions. I found myself fighting the steering a lot, till I went to a 2.3 on the front.

Your conditions will be different of course. My particular issue was too much float on the front tire was not letting me create a rut with the front tire, which the rear tire could follow to get a sharp turn in loose dirt or sandy track.

Experiment with different tires on the rim you have to start with, that gets expensive enough. if you go a bigger rim, it will change your fork angle, so consider that too. slacker may improve your ride, or not, depending on what you do. Really high speed riding will like slacker, while riding on rock staircases will likely not want slacker headset angle.

And nothing extereme, I put a 26" fork and wheel on a 24" bike, and man, that sucked balls. So don't put a 29 er fork on that bike.

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Re: Bigger tire in front?

Post by craneplaneguy » Jan 02 2019 9:23am

No speed involved, ha ha, mostly just slowly trucking along in a remote area, by myself, so I take it easy., and it's always about extending my range. Maybe the last mile or so back to camp I'll romp on it a bit. Always uphill to start, Idaho makes that easy. I fly into a remote area, and then get the Montague out and get even more remote, and while a non repairable flat will and has been a huge pain (long walk, at the end of the day, no fun) a flat won't kill me. Great info here, that tire sealant video was great.

I have one of these on the way: https://surlybikes.com/parts/tires/extr ... l_26_x_2.5 Since I already have several new tubes in stock, I'll just stay with tubes for the time being, (but I inject Stans thru the schrader valve, got a tool for that) at least until I use them up. I now ride, after an incident last summer, with two sources of air, a manual one, or my electric one, and a couple C02's. Since it's winter, my first rides will be pavement, hopefully the ET tire makes a decent pavement tire also, supposed to anyway. One good thing about being ignorant about something, is you don't know what you don't know! What may be unacceptable handling to a biking expert will be just fine for me, think about it, not knowing any better can be an advantage.

This picture was at a bit over 8K, and finished at bit over 9 I think, when I reached the top/couldn't go higher. Started at 6400', 6 miles away. Lot's of sharp rocky shale, never did get a flat though. The old fire lookout on top had a wood stove and a couple old lawn chairs, a great place to camp out if you wanted to, I didn't. During the recent total eclipse, this area was prime viewing, I flew over this lookout and about 30 people were up there.
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Re: Bigger tire in front?

Post by E-HP » Jan 02 2019 3:05pm

craneplaneguy wrote:
Jan 02 2019 9:23am
I have one of these on the way: https://surlybikes.com/parts/tires/extr ... l_26_x_2.5 Since I already have several new tubes in stock, I'll just stay with tubes for the time being, (but I inject Stans thru the schrader valve, got a tool for that) at least until I use them up. I now ride, after an incident last summer, with two sources of air, a manual one, or my electric one, and a couple C02's. Since it's winter, my first rides will be pavement, hopefully the ET tire makes a decent pavement tire also, supposed to anyway. One good thing about being ignorant about something, is you don't know what you don't know! What may be unacceptable handling to a biking expert will be just fine for me, think about it, not knowing any better can be an advantage.
Maybe the next time you have the tire off, do the gorilla tape thing on the rims? Sort of like a tubed tubeless setup, with the rim all sealed up. That way, if the tube fails, the Stan's may still be able to seal the tire.

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Re: Bigger tire in front?

Post by Chalo » Jan 02 2019 3:56pm

Using a fatter tire in front has been done from time to time by both MTB and BMX racers.

Fatter tires are not inherently slower--actually faster for any given tire construction and pressure. However, fatter tires are usually of coarser and rubberier construction, and it only makes sense to run them at lower pressures to yield their benefits. Both those factors cause higher rolling resistance.

Whatever added drag you get in the front will be minimized because there's quite a bit less weight borne by the front wheel.

In the heyday of downhill racing, substituting a 24 x 3" wheel and tire for a normal 26 x 2"ish wheel was a common retrofit to moderate changes to ride height and steering geometry. If you have disc brakes, that's another option available to you.
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Re: Bigger tire in front?

Post by billvon » Jan 02 2019 4:50pm

craneplaneguy wrote:
Jan 01 2019 7:29pm
I have heard of some using a smaller tire in the rear, to get a better gear ratio
Do the math on that before trying it; the ratio changes are pretty small.
--bill von

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Re: Bigger tire in front?

Post by Chalo » Jan 02 2019 5:49pm

[Duplicate post put up mistakenly as a typo correction.]
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Re: Bigger tire in front?

Post by amberwolf » Jan 02 2019 6:06pm

For Craneplaneguy, something to consider about tubeless (or any other sealant) is temperature; I've seen that you go to some cold-looking places.

How well do the sealants work under those conditions?



Regarding more air in a slightly bigger tire--yes, it makes a great deal of difference, though it isn't always enough. On SBC's rear tires, I went from 2.1/2.2" x 20" bicycle tires to 2.5" x 16" MC/moped tires, and at a guess the volume of air is close to (but not quite) double, at a greatly lower pressure (50PSI+ vs 34PSI), but stiffer sidewalls and tread. Same rims. Huge ride difference; also stickier compound, so no more unintentional sliding around on the road. (can still do it if I intend to, which is good for avoiding some things).

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Re: Bigger tire in front?

Post by craneplaneguy » Jan 02 2019 6:50pm

Mostly I just want more rubber meeting everything on the trail first, a larger contact patch.

My current tubeless setup on my fatbike is working fine, and I just got done with a short ride, in 18 degree temps. But most of our winter riding is 20-30's temps.

I am hoping to just it run fairly low on a trail, then air it up a bit for road riding, nothing too extreme on either end. Right now my fat front tire is about 5 lbs, real squishy, I won't go that low! But it sure is nice on the snow.

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Re: Bigger tire in front?

Post by Bigwheel » Jan 03 2019 6:01pm

It is my experience that a narrowish tire on a wider rim has as much effect for running lower psi reliably than a wider tire on a narrow rim. My preferred setup for the front is a 2.3 tire on an i35 rim and although I use 700c the same theory should apply to either 27.5 or 26". With this combo I can run 15psi tubeless with no issues in all the terrain configs I run across. So if you do go to another rim you might consider doing a wider one.

Like Dan I don't like a wider type tire in the front as I find they tend to self steer, especially at the desired lower psi, and after years of using 2.3ish tires I am more used to how they handle but do like being able to use the lower psi than the 30psi I used previously with narrower rims and tubes for my mtb. I do use a 2.8 on the rear though mounted on an i35 650b rim at about the same psi and find that to work well for traction and small bump absorption while keeping close to the overall diameter of the front wheel so as to not mess with the stock geometry nor affect ground clearance.
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I prefer tubeless now that I have come to grips with it's intricacies but I still have one tubed front hub wheel, that I run tubeless sealant in the tube, but it is a 45c (1.75) tire on an i25 rim on my drop bar bike that I run at around 35psi. At that psi you can really rip on gravel comfortably and confidently.

The one thing you want to watch out for if going to a wider rim is that some manufacturers list outer rim width and some list inner. The rims I use designates the inner dimension, thus the i.

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Re: Bigger tire in front?

Post by Deafcat » Jan 04 2019 2:58pm

amberwolf wrote:
Jan 02 2019 6:06pm
For Craneplaneguy, something to consider about tubeless (or any other sealant) is temperature; I've seen that you go to some cold-looking places.

How well do the sealants work under those conditions?
Orange Seal Sub-Zero for winter and year-round tubeless use. It is a slightly improved sealant over the usual Orange Seal or Stans, with below-freezing compatibility and can be used year round.

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Re: Bigger tire in front?

Post by craneplaneguy » Jan 04 2019 9:25pm

The rims I use designates the inner dimension, thus the i.
[/quote]

OK, I knew I would figure that out without having to ask, WTF? I had seen that term and my eyes just glazed over, not knowing what it meant, now I know, thanks! My rim is 22 mm, inside. My tire has arrived, looks good, I'll mount it tomorrow.

This Montague also has a Rohloff hub, and I noticed some looseness in the spokes, actually just one, 2,000 +- miles since first laced up. So, I dropped it off at my LBS, and asked them to true it up, and made mention of the fact that the Rohloff requires higher spoke tension then "normal". The number specified I remembered was 1000, but the unit of measurement escaped me. In eyeballing this loose spoke, I also noticed a bulge in the rear tire on the sidewall, and general wear and tear, that's what started this whole tire upgrade. I may try this larger tire on the rear rim first, though I don't think it will have enough clearance, it's kinda tight back there, but the front has plenty of room thanks to the sus fork. Due to it being winter here, my first riding on this bigger tire in front experiement will be on pavement.

Great pic Bigwheel, looks like some of the places I ride! What was your elevation?

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Re: Bigger tire in front?

Post by Marin » Jan 04 2019 9:40pm

I have been running those tires for a while and really like them
Marin ex-rental hybrid with 48v bionx...sold
Specialized hardrock with magic pie 4-5
Lunacycle with l/r mid drive coming soon
Kona Caldera with QS 30H (maybe), and phase runner
Giant Yukon bbs02
Kona Abra Cadabra bbshd
Wildfire fat bike bbshd

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Re: Bigger tire in front?

Post by craneplaneguy » Jan 28 2019 12:16am

After I did some heavy research on how to lace up and true my new front rim to my new hub (3 of the 6 disc bolts stripped out, so I bought a new hub also), I ended up taking it to my LBS and told them to call me when it was done....yeah I wimped out, but no regrets. It turned out perfect. The 2.75" Surly Dirt Wizard nicely fills the front sus fork now, just like I wanted. Can't go any bigger, so it's big enough. Only one ride so far, on pavement, but jumped a few curbs, and it is noticeably more cushy, besides being wider it quite a bit deeper (thicker?) also. Noise is not an issue either, kind of surprised about that. The only bad thing is the side wall arrow showing direction of rotation is backwards :roll: , but no biggie as I am staying tubed for now, so will break it down and try and get it right this time.
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Re: Bigger tire in front?

Post by Chalo » Jan 28 2019 10:44am

craneplaneguy2 wrote:
Jan 28 2019 12:16am
The only bad thing is the side wall arrow showing direction of rotation is backwards :roll: , but no biggie as I am staying tubed for now, so will break it down and try and get it right this time.
It's customary to orient the tread reversed on the front, because there's no drive torque (but there is braking torque, which is reverse). The directional arrows on tires sometimes reflect this.

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Re: Bigger tire in front?

Post by craneplaneguy » Jan 28 2019 12:57pm

No kidding? So I didn't screw up, but I planned it that way? Perfect, I'll leave it as is, and now I can justify why in case I get called out on it.

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Re: Bigger tire in front?

Post by Bigwheel » Jan 29 2019 3:56pm

craneplaneguy wrote:
Jan 04 2019 9:25pm
The rims I use designates the inner dimension, thus the i.


Great pic Bigwheel, looks like some of the places I ride! What was your elevation?
[/quote]

That is the east face of Mt. St. Helens taken at the beginning of the Plains of Abraham. Roughly 4850' or so. The Smith Creek Trail down from there was the single track most reminiscent of my past high altitude experiences as I lived in Crested Butte for a long time and am no stranger to the elevations you ride at.

On a visit there a few years ago I rode to the top of all the drainages around town on my all road front hub bike and they are around 9k'. Now that I live at sea level there is no way I could have made the rides I did in the time span I had without the assist for sure. I did the Pearl Pass 40th anniversary overnight ride on my single speed after and there is no way I could have made that ride without the rides I did on assist helping to acclimate me to the elevation either.

As to the above relating to tire profile on a narrow rim with a wide tire that makes the tire more bulbous I feel that it doesn't allow for the lowest psi possible, which to me is the goal as traction is key as well as compliance, because the side walls flex too much downwards and when the sidewalls collapse around an obstacle there is a greater chance of pinch flatting. Whereas with a wider rim and a straighter profile the sidewall is more apt to flex outward and there is less chance of pinch flats. Also it allows for the lowest psi to be run, especially with a tubeless system. I might have already said that in my other post so sorry for repeating but I really believe that a wider rim has as much or more influence on running wide tires than most give them credit for.

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