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Rim Widths, 2016

AngryMetalsmith

Business is good, thanks for asking
Jun 4, 2006
21,210
10,009
I have no idea where I am
i just don't get the whole ultra low air pressure trend. i'm about 210-215 lbs geared up, and i can't run anything lower than 30 psi without it feeling squirrely as fuck, plus the hit to rolling resistance. trail or DH, even with wider rims (granted not the super wide modern nonsense) and DH casings, the lowest i could get was maybe 27-28.
I'm at 175 llbs. and run rims with a 23.4mm inner width with 25 psi front (tubeless) and 28 psi in the rear (tube). Was running 25 in the rear until I dented the rim to the point it won't hold air set up tubeless. Occasional I feel something kind of squirrelly in a fast corner. But every time I've gone back and looked at the corner, there are drift marks. So maybe you are really cornering faster than you think ?
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,067
5,976
borcester rhymes
have you tried 2.5 tires on the 30mm id rims? I think they would get along better with them than the 2.35's. What width Conti's are you running on the Stans?
No, that would be more logical, but my experience with plus sized tires tells me it ain't worth the weight, and with my 29er I really wanted to keep the brotating weight way down. Plus, from what I understand, most of the "too narrow tire on a too wide rim" comes down to squaring off the tire profile, which is mostly a problem on certain tires.

Not sure on the contis, I believe 2.5s. Whatever is factory on the GT Fury I have.
 

slyfink

Turbo Monkey
Sep 16, 2008
9,323
5,074
Ottawa, Canada
i just don't get the whole ultra low air pressure trend. i'm about 210-215 lbs geared up, and i can't run anything lower than 30 psi without it feeling squirrely as fuck, plus the hit to rolling resistance. trail or DH, even with wider rims (granted not the super wide modern nonsense) and DH casings, the lowest i could get was maybe 27-28.
It depends on the terrain you ride. My buddy who has the derby rims (i35 I think?) runs them with Hans Dampfs. We have lots of rocks and roots here with lots of up and downy twisty turny no-flow stuff locally. The wide rims at low pressure absorb lots of the medium roots and rocks, and that makes a pretty huge difference in rolling speed. He's a competent descender, however with this setup he can feel the rims ping off rocks and/or fold over in corners when things get fast. So he has to choose how to set up his tires: cushy for bump absorption, or harder for fast dh and cornering.

When he told me that, it pretty much made up my mind for me: mid-width rims with "normal" pressures that allow me to have fun on the downs is what I'll run. He can wait for me at the top of the climbs, I don't care if I'm not at the top first.
 

mrgto

Monkey
Aug 4, 2009
295
118
Totally true. Cat3/expert XC racers push their equipment harder than the majority of AM/DH riders. It's amazing what abuse bikes will take, you get a much better appreciation for it at Mach 3 down a rough trail on a hardtail. You also see how little difference many gear/bike choices make on your time/speed.
image.jpeg
 

SylentK

Turbo Monkey
Feb 25, 2004
2,324
869
coloRADo
I think there is a correlation between tire size and rim width. And there are points of diminishing returns. I just happen to be dreaming of the wheels I'd get for my new trail pistol :brows:...(easy, i was just dreaming)...and found some interesting data on enve's site. For 2.4 to 2.5 tires, they recommend 30i. Check it out. It's a good read.
 

mrgto

Monkey
Aug 4, 2009
295
118
Yes, RLY.
Bullshit

I've watched those guys and gals and they can't go downhill to save their lives. It's sad really. The tour is full of them too, boy can they climb but watch the fuck out when it's time to point it down.

I'm sorry but XC is not hard on any mtb gear except lycra.
 

kidwoo

Artisanal Tweet Curator
I was at the mammoth nationals two weeks ago and the top of the crop of xc guys and gals are rippers descending considering the shitbox equipment they're on.


But cat3/expert xc racers...........oh fucking please.

I use to race that class in xc and would regularly bunny hop over people busting their asses trying to walk down big mean scary sections of trail that ANY dher would chuckle at.
 

mrgto

Monkey
Aug 4, 2009
295
118
I was at the mammoth nationals two weeks ago and the top of the crop of xc guys and gals are rippers descending considering the shitbox equipment they're on.


But cat3/expert xc racers...........oh fucking please.

I use to race that class in xc and would regularly bunny hop over people busting their asses trying to walk down big mean scary sections of trail that ANY dher would chuckle at.
That's what I'm saying. You have to be a pro XCer to even be able to go down hill and not look silly. I watch these races and it's really sad.
I'm just a hack, but ffs i use to rip on a fully ridged Giant back in the day and I could kill some of these "XC" guys on the wee down hill sections they struggle down.
 

boostindoubles

Nacho Libre
Mar 16, 2004
7,875
6,176
Yakistan
I do early season xc races to help get me into shape for the shredding season.

I will concur, the guys on the podium can rail but everyone else is shit in any dh section.
 

-C-

Monkey
May 27, 2007
296
10
Another XC rim dude were :)

I must have some deep rooted confusion issues, as I went from 30mm ID carbon rims back to skinny 23mm aluminium ones.

My gnarly XC riding kept breaking the carbon ones.
 

Jm_

sled dog's bollocks
Jan 14, 2002
18,980
9,639
AK
Bullshit

I've watched those guys and gals and they can't go downhill to save their lives. It's sad really. The tour is full of them too, boy can they climb but watch the fuck out when it's time to point it down.

I'm sorry but XC is not hard on any mtb gear except lycra.
Are you racing expert/pro? I'm racing at the highest level in this state. Don't kid yourself and think that you are all that because you can do a 3 foot drop. I would say in every discipline, road, DH, enduro, xc, cyclocross, the pros are pushing their equipment far harder than non-racers and lower level racers. Gaps and jumps that we usually do on our AM bikes, hitting on our XC hardtails with the seat all jacked up, and that's not even the rough stuff. Maybe it will be easier for you to swallow by saying "at the highest levels of competition", but plenty of the expert racers are not far removed from pros, besting them in some races.

Maybe people's perceptions are based on being so far back from the race leaders that they are mixed with lots of recreational XC riders.
 
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mrgto

Monkey
Aug 4, 2009
295
118
Are you racing expert/pro? I'm racing at the highest level in this state. Don't kid yourself and think that you are all that because you can do a 3 foot drop. I would say in every discipline, road, DH, enduro, xc, cyclocross, the pros are pushing their equipment far harder than non-racers and lower level racers. Gaps and jumps that we usually do on our AM bikes, hitting on our XC hardtails with the seat all jacked up, and that's not even the rough stuff. Maybe it will be easier for you to swallow by saying "at the highest levels of competition", but plenty of the expert racers are not far removed from pros, besting them in some races.

Maybe people's perceptions are based on being so far back from the race leaders that they are mixed with lots of recreational XC riders.
I'm sure your a strava champion in your state.

I push my equipment to the extreme because I'm 235lbs so my little " 3 foot drop" = your 10 foot drop and I have lots of shimz to help.

Please let me know where I can watch the highest level of competition XC racers riding dh courses for a XC event. I'll bring the beer.
 

Gary

"S" is for "neo-luddite"
Aug 27, 2002
7,635
5,552
UK
@Jm_
based on nothing more than the evidence in clear view at World Cup and National XC races all the top guys are highly skilled but quite a lot of the guys further down the results still really aren't.
of course there is a smattering of guys with good skills in every category. I'm not sure what you're getting your knickers in such a tangle about this for though?

none of those guys however
are pushing their equipment far harder than non-racers and lower level racers. me
They're on 4lb full suspension frames and bend if you get a rut wrong rims shod with paper thin tyres FFS!
Seriously. That shit wouldn't last the length of a normal XC ride for me taking nothing but my usual s hardtail* lines.
Woo made a pretty good point about what he witnessed a couple of weeks ago in that respect!

I love watching WC XC btw... have done since I first raced it 25 years back... I find it way more interesting than Enduro but just like EWS a lot of the field are only good viewing for the entertainment value created by their shitness.

* ~ 30lb of durable dependable 100mm forked HT

.
 

slimshady

¡Mira, una ardilla!
I would say in every discipline, road, DH, enduro, xc, cyclocross, the pros are pushing their equipment far harder than non-racers and lower level racers.
There is one thing pros have on their side, and most of us mere mortals lack: finesse and technique. That's why Commencal and some other brands have a group of regular Joes testing their stuff. They found out Pros would go not hard enough on their equipment. Plus most of the elite level guys replace their shit way before they reach a critical failure point.
 
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kickstand

Turbo Monkey
Sep 18, 2009
3,441
392
Fenton, MI
i just don't get the whole ultra low air pressure trend. i'm about 210-215 lbs geared up, and i can't run anything lower than 30 psi without it feeling squirrely as fuck, plus the hit to rolling resistance. trail or DH, even with wider rims (granted not the super wide modern nonsense) and DH casings, the lowest i could get was maybe 27-28.
This.

my 60lb 10 year old runs maxxis DH tires at 18-20 PSI on 23-25mm width rims for downhill and still dents the shit out of rims

My 130-140lb wife runs DH tires in the low 20's on the same rims I use and pings them off rocks from time to time.

I'm down to 165 this year and even at about 30 psi I'm smashing rims.

Yes, this is in a DH race environment, but this is the DH forum, and I find that we actually run our tires on the softer side compared to many at races.

I also find DH races a pretty good place to get an idea of how hard you can push equipment, because #cat3XCiswayharder
 

kickstand

Turbo Monkey
Sep 18, 2009
3,441
392
Fenton, MI
Totally true. Cat3/expert XC racers push their equipment harder than the majority of AM/DH riders. It's amazing what abuse bikes will take, you get a much better appreciation for it at Mach 3 down a rough trail on a hardtail. You also see how little difference many gear/bike choices make on your time/speed.
This is funny. I mean, this is funny.
 

weedkilla

Monkey
Jul 6, 2008
362
10
What am I missing?
729's didn't give as nice a tyre profile as a 23mm internal rim, and a 2.35 most brands or 2.5 maxxis is about as big a tyre as I want to run. Same as the last 10+ years.
Didn't we do this all before?
Sun double wide anyone?
 

Sandwich

Pig my fish!
Staff member
May 23, 2002
21,067
5,976
borcester rhymes
What am I missing?
729's didn't give as nice a tyre profile as a 23mm internal rim, and a 2.35 most brands or 2.5 maxxis is about as big a tyre as I want to run. Same as the last 10+ years.
Didn't we do this all before?
Sun double wide anyone?
well, many tires are now optimized to be run on wider rims, so you get a better pairing of tire and rim profile.

rims are getting wider to offer better sidewall support so you can run even wider tires (mtbr) and you can run lower pressures without tires rolling off your rim (this actually works, to a degree).

Personally, I'd like to go to about 28psi without pinch flatting. My fucking contis offer great grip but I can't drop sub 32 without pinch flatting every time I ride so now i'm at 35 psi and a DH tube, which both have pretty obvious negative effects on the way the bike rides.

Not saying this is due to the width of my rims, but if wider rims offer lower pressure without pinchflatting or destroying the rims, then it's worth pursuing. Personally I should probably just ditch the contis or go tubeless.
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,913
1,268
SWE
About procore, I am running a ghetto version of it on the rear wheel of my hardtail with a tubular tire inside. Another advantage that has not been mentioned before is the lower rolling resistance: with ghettocore you do indeed increase the rotational mass to something close to a dh casing but the rolling resistance (you know, the energy necessary to flex the sidewalls while rolling) remains at the level of any good trail tire.
 

CheetaMike

Monkey
Jul 17, 2016
229
57
Whonnock BC Canada
speaking of Procore and such , anyone familiar with the set-up that Graves uses ?? he mentioned it in a review on his bike on PB recently .

and pulled the trigger bought some 345 OOZY,s for the next bike build , pick them up later today .
 

slimshady

¡Mira, una ardilla!
not sure it,s a ghetto set-up he ran years back and just started using it again this season . I think he splits a tube and them sandwiches it between the rim and bead of the tire

http://www.pinkbike.com/photo/13709963/
Soooo... Ghetto tubeless? I ran my past trail bike that way. Suppossedly, it's harder to snakebite the side of the tire because of the extra cushion that layer of tube gives you. But in my experience, you can't drop the pressure as much as with a regular tubeless setup. Burping the tire gets easier because the tube prevents the tire bead from biting into the rim wall.
 

Nick

My name is Nick
Sep 21, 2001
24,038
14,650
where the trails are
Is really not. You don't trim the excess tube until the tire is mounted. I rode this set up years ago and it worked great, pre UST days.

Now almost everything tapes /seals pretty well, and rims are much better, no benefit to this anymore, imo.
 

kickstand

Turbo Monkey
Sep 18, 2009
3,441
392
Fenton, MI
Noob.

that's ole skool yo

I used to do that on mavic 721s. It works like a champ. Gives a little flap that hangs over the edge of the rim and helps prevent poking a hole in the tire from pinches.


Anybody remember maxxis rim strips? oohhhh yeah
I'm just thinking about how tight my tires fit to my rims as is, then trying to keep the tube in place while putting them on, sounds like a job for a dude with 2 extra hands, I actually want to try it though seems if done right it could be very reliable for someone like me who doesn't corner well enough to be worried about the tires blowing off the rims as mentioned above as one of the cons
 

Happymtb.fr

Turbo Monkey
Feb 9, 2016
1,913
1,268
SWE
I'm just thinking about how tight my tires fit to my rims as is, then trying to keep the tube in place while putting them on, sounds like a job for a dude with 2 extra hands, I actually want to try it though seems if done right it could be very reliable for someone like me who doesn't corner well enough to be worried about the tires blowing off the rims as mentioned above as one of the cons
It is actually quite easy to mount. You start with a 20" tube that you inflate until it is big enough to go round your rim. Once the valve in the hole, you just splice the tube in the middle and all way round. Since the tube is smaller than your rims it will sit tight on the rim bead and around the rim. After that you mount your tire as usual but with the spliced tube between the tire and the rim off course. Don't forget the tire sealant ;) inflate and ride!