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Carbon rims and tire pressure

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On 4/6/2019 at 10:10 AM, AustinBike said:

This *might* help a bit on tire width and rim width:

https://www.notubes.com/technology/wide-right

I have moved to the Arch MK3's on 2 of my bikes and have one set of older Arch EX's (coincidentally enough on my newest bike, long story...)

I love the MK3's and even though I am not an enduro guy, the extra width makes a difference. 

DT Swiss used to post a tech page like that but I can't find it. I think the brand of tire you run has a bigger effect on how your bike feels more than +-5mm rim width does. Now if you were going from 20mm IW to 30mm IW you'd notice a difference. As most of us know tire size numbers seem to be very arbitrary across brands. Tire width and case volume is a big factor in tire shape when it's mounted on a rim. But generally the Stan's guide is a good start. Disclaimer; not a fan of Stan's rims.

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2 hours ago, Chief said:

Disclaimer; not a fan of Stan's rims.

Hopefully these newer ones are better than the MK3

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My MK3's are awesome. Have them on two of my three bikes and love them. I'd replace the Arch EX with Arch MK3 on my new wheels, but they are in pristine condition so I have no need to waste good rims, but the minute I trash one the whole set is getting rebuilt with MK3's.

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My experience with MK3s are different than yours. The pic below is the first 10 minutes of owning a flow MK3. It was also damaged on a lip that I'd hit with my old flow EXs multiple times without damage. Making it even worse was the fact that the racing ralph that weighs under 700 grams that was on that rim was completely undamaged and was used on several bikes later. First sign of trouble was they made the MK3s wider yet lighter than EX.  The MK3 arch on my wife's bike seem to be okay.

 

 

STANS.jpg

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15 hours ago, ATXZJ said:

My experience with MK3s are different than yours. The pic below is the first 10 minutes of owning a flow MK3. It was also damaged on a lip that I'd hit with my old flow EXs multiple times without damage. Making it even worse was the fact that the racing ralph that weighs under 700 grams that was on that rim was completely undamaged and was used on several bikes later. First sign of trouble was they made the MK3s wider yet lighter than EX.  The MK3 arch on my wife's bike seem to be okay.

 

 

STANS.jpg

that looks like you had really low pressures and hit something really damn hard

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48 minutes ago, Seths Pool said:

that looks like you had really low pressures and hit something really damn hard

Surprisingly it wasn't that fast or low pressure. The sidewall on the lightweight racing ralph XC tire was completely unblemished but the rim caved in enough to bend the hoop out of shape to where the spoke had about 2mm of play. Cased that same thing a few times on my flow ex and never even bent a lip.

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On 4/4/2019 at 5:00 PM, Seths Pool said:

im also on my first set of carbon wheels and honestly dont feel/notice the benefits. quite the opposite rather. im always paranoid about breaking them, running Cush core and dealing with the complications/hassles of that, blah blah blah. and the weight savings are minimal if non existent. I probably wouldnt hesitate a minute to sell them and get the new Stans flow EX3 rims.

 

I'm quoting myself to add an update to my carbon wheel experience.. or should I say, we are one composites experience rather. 

read it - 

I bought my first set of carbon hoops in October of last year, but didnt take my first ride on the fancy carbon wheel set until January.

we are one composites 29", model: Agents (enduro rim), with cush core

2nd ride on this new wheel set, I get a rock puncture right in the middle of the tread on a brand new Maxxis Double Down Aggressor 29 x 2.5 WT that Stans nor a plug would fix

apart from the hole the tire was brand new

I took another Maxxis DHF EXO casing 2.35 tire (not brand new but seemingly a fine tire) installed it and cush core, and it started blowing off the rim at only like 40lbs of air during the initial mounting, noticed a bulge in the tire and threw it away - blamed the tire or maybe somehow a faulty cush core install

so I take that brand new aggressor with the hole in it, cleaned out the inside and patched the tire, then went to install it back on the carbon rim with cush core as it had been before

pumped it up to 40 PSI - ***BOOM!*** blows off the rim like a bomb, deafening, sealant sprays everywhere... WTF

so now I'm suspicious that cush core is causing this phenomenon 

decided to reinstall the tire without cush core to see if there was a different result - same damn thing. this time the tire blew off the rim with only like 30something psi in it. I'm pissed, I'm frustrated, Stans sealant is fucking everywhere, my ears are ringing from the repeated blasts of the tire blowing off the rim. and with this tire having already blown off the rim once, I couldnt tell if the 2nd time had been caused by the rim itself, or the tire bead having been compromised/damaged from the first blow off

THEN I look and notice that one of the blasts caused the pump handle/nozzle to hit the rim and put a very subtle crack in the rim.. F'ing GREAT!

we are one has a no questions asked unlimited replacement policy. they send you a new hoop, and normally you have to pay for your own spokes/nipples/wheel building. with the circumstances of the repeated tire blow offs and stuff, they said they wanted to get the rim in their hands to make sure it wasnt an issue with the rim, and that they would send me a pre paid label, id send my entire wheel in, they would rebuild the entire wheel and send it back to me complete. 

 

I was happy wth this, they sent me a label, I shipped it, all is good..

to mention - this Chris King hub is 142 non boost with a 6mm boost adapter spacer which I included in a ziplock bag and taped to the wheel. it has to be dished to 148 boost using the boost adapter spacer and a dishing tool

they received it, I clearly and directly communicate with the the boost adapter spacer, the acknowledge blah blah blah

 

2 weeks or so goes by and I get a box delivered from them, "damn this box feels light" I think to myself. I open the box - they sent me a warranty rim all by itself 

the next day before I had a chance to contact them about the mistake, I get an email -  "we realized we made a mistake and sent you a rim by itself, we can go ahead and send you back your hub and you can pay to get it laced and and built"

im like "woah woah dudes, I already sent yall my entire wheel, waited over 2 weeks, and we already agreed ya'll would build the wheel and send it to me completed. I would appreciate if you stuck to the agreement"

I have a text conversation with the guy who was originally handling this whole ordeal from the beginning, and he assured me they would build the wheel and send it to me complete, and that I should just hold onto the extra warranty carbon hoop for anything that happens in the future. 

 

OK, so im still happy with this outcome so far even with the complications.

 

so yesterday - I finally get the 2nd box delivered from we are one. open it, and my complete Chris King wheel with brand new carbon hoop is in the box. 

but THEN I notice that the Cheris king 142 axle end cap, and the 6mm boost adapter spacer is nowhere to be found, and the tech sheet says it was build/dished to non-boost 142mm.

 

like God F'ing Damnit dudes! I appreciate the fact that they stuck to our agreement, but they literally fucked up every opportunity they had. every step of the way. over a month later I still have a wheel I can't use, already spent another $16 on a king axle cap after shipping, and still am missing a 6mm boost adapter spacer, AND still have to re-dish the wheel!

I feel like they are forcing me into being "that annoying customer". I'm not trying to be a pain in the ass. BUT QUIT MESSING EVERYTHING UP!

 

so far I've quite frankly absolutely hated my carbon wheel experience. absolutely zero benefits thus far and is proving to be just one big total pain in the ass. 

Edited by Seths Pool
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^^What a freakin' mess and a terrible experience @Seths Pool.

 

While I haven't had to deal with SC on any warranty related issue (yet!), I'm glad I've gone with them given their reputation for handling issues quickly, and the supposed "not limited" lifetime warranty on the Reserve rims. I'm well over 1000 miles on them and they've been great.  My only real concern is failure of the rims when I really need them, like a week-long trip. This isn't an issue if it's a road trip, I just pack extra wheels. But this may become a real pain if I'm flying since 2 wide wheelsets will be tough to pack into a box. 

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Interested in these guys as well.  They're literally down the street.

Carbon that close to the rocks doesn't do it for me.  I've bent up aluminum rims and they've never catastrophically failed and sent me OTB.  If a carbon rim fails, it seems like it will really fail...

 

My experience is that aluminum just bends if you roll out with too low of a psi and kiss a rock. Yes you can bend it back with a pair of pliers, but it is forever ugly and weak.

 

Carbon is super strong unless there is a layup defect. You can feel the rim kiss the rubber and know your psi is a little low. On my stans, that same feeling resulted in a bent lip.

 

It stays so unbelievably true compared to aluminum until you ding enough spokes to really screw things up.

 

You ever cracked an aluminum rim and ridden it a lot? As long as you are holding air, you can pretty much ride cracked carbon home. We cracked specialized rim and still had to do a few rides/ races on it before we had it warrantied.

 

I’ve gone out way low on psi (laziness) and pinch flatted tires and slammed square edge ledges. The rim barely has a mark. Aluminum would probably be dead.

 

I’ve ridden dirt wheels. Dirt components built me up a few wheels and they have been fantastic. I do not have the current rim offerings from them, but I will replace my bontrager’s with them soon. Buy from Patrick! He is awesome.

 

 

Regarding PSI... I maybe went a couple of pounds lower when switching to carbon. It allowed me to slowly find the ideal psi without fear of bending the lip. I run 24-26 rear depending upon tire size. Front is 21-23. I’m a hair over 190 in my gear and my bikes are 22-25 pounds.

 

All my tires are 2.25-2.35.

 

Sent from my iPhone using Tapatalk

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6 hours ago, FJsnoozer said:

It stays so unbelievably true compared to aluminum until you ding enough spokes to really screw things up.

 

This!   My 2nd hand Knox came with a few dinged spokes, and a few that were not a match.  I started breaking some spokes, the tensions were uneven.  I replaced all the dinged spokes and all the non-matching spokes, tensioned it even and it's perfectly true.  With aluminum, I find that once I'm having to replace spokes or true the wheel, the spoke tensions are going to be off for the rest of the life of the wheel.  That means either loose spokes frequently, or broken spokes now and then in my experience.

Sorry about your troubles Seth.  Thanks for the warning on this company.  I'm considering a new set of wheels for my SS and I've got Knox and Dirt Components on my list now.

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9 hours ago, Seths Pool said:

 

 

so far I've quite frankly absolutely hated my carbon wheel experience. absolutely zero benefits thus far and is proving to be just one big total pain in the ass. 

Pretty much this

 

Someone has to see the irony of paying 2-3k for wheels that are less reliable than aluminum without any real true weight savings. You have to add tire inserts, and DH carcass tire only to have them ride rough as sh*t in the end. Once you add all the shite to keep them alive, saving 100 grams doesnt matter..... Oh wait! Zipp is making carbon wheels that ride like aluminum now🙄

Never again

 

 

 

Edited by ATXZJ
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10 hours ago, AntonioGG said:

  With aluminum, I find that once I'm having to replace spokes or true the wheel, the spoke tensions are going to be off for the rest of the life of the wheel.  

This is one of the few benefits of carbon. Once an aluminum rim gets severely out of true it's never the same, impossible to get even spoke tension and trueness together. Regardless of how out of true a carbon hoop gets once you relieve spoke tension it goes back to its original shape, whereas aluminum once it's bent it wants to stay that way.

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This is one of the few benefits of carbon. Once an aluminum rim gets severely out of true it's never the same, impossible to get even spoke tension and trueness together. Regardless of how out of true a carbon hoop gets once you relieve spoke tension it goes back to its original shape, whereas aluminum once it's bent it wants to stay that way.


I need some internet advice on this rim. I think I bent it when I cased it on the bridge by the railroad tracks on the BCRT by Mulligan. The bead hasn’t broken and it still holds air but sealant is weeping some. I’ve done a whole day at Spider Mountain and rode for a couple of hours on it last night. Is this fixable? Should I just not worry about it unless it gets worse? Is this kind of thing under warranty? The rim is six months old. a057297c0ffa032ff1bfd7cdee025e5c.jpga057297c0ffa032ff1bfd7cdee025e5c.jpg9f3a18cd83cae3da8d54b60bb9e706d5.jpg


Sent from my iPhone using Tapatalk

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1 hour ago, Browndog said:

I need some internet advice on this rim. I think I bent it when I cased it on the bridge by the railroad tracks on the BCRT by Mulligan. The bead hasn’t broken and it still holds air but sealant is weeping some. I’ve done a whole day at Spider Mountain and rode for a couple of hours on it last night. Is this fixable? Should I just not worry about it unless it gets worse? Is this kind of thing under warranty? The rim is six months old.


Sent from my iPhone using Tapatalk

 

Take that tire off and use a vice grip with some electrical tape on it. Bend that baby back and keep on riding. It will not have the same structural integrity if you hit it again in the exact same spot, but it will ride normally. I cannot count the number of times I have just bent my wheels back into shape. Yay aluminum! 

Edited by csmceuen
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11 hours ago, csmceuen said:

Take that tire off and use a vice grip with some electrical tape on it. Bend that baby back and keep on riding. It will not have the same structural integrity if you hit it again in the exact same spot, but it will ride normally. I cannot count the number of times I have just bent my wheels back into shape. Yay aluminum! 

+1. I've got a wheel that I've done this to at least 3 times. It takes a little longer for the sealant to stop seeping from a new tire install, but other than that no issues.

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19 hours ago, Browndog said:

Is this kind of thing under warranty? The rim is six months old.

My new bike was only a couple of weeks old when I did something similar. While I can't speak for every shop / bike brand, my Bontrager Line Elite rim on my Trek Remedy from BSS was not covered, although BSS did give me a discount on the replacement. This is another advantage for carbon in my opinion, as most carbon wheel manufacturers have generous warranty / replacement. Even Trek offers a 2-yr free replacement on any of their carbon wheels that are damaged while riding. I'm going to ride with higher pressures for now, but eventually I'll be looking for a new carbon wheelset to replace these with. I've had countless rim strikes on my DT Swiss XMC1200s due to being lazy about checking my tire pressure, and after 2.5 years, they still ride like they did on day 1. And in that same span, I've only broken 1 spoke. 

IMAG2609.jpg

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I'm about to build up a new wheelset for myself and while I've entertained the idea of carbon for my road bike, I see zero benefit on my Mtb. I'll be building Flow MK3, which have done well on my rigid SS. 

My experience is that an Al rim has to be super tweaked to not be truable if you restart tension from zero. If you don't take tension to zero, a bad tweak will never come out. 

For the time and price I'll stick with Al Stan's.

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My MK3’s have been great. 

Watching this thread tells me:

1. All of this is highly dependent on situation

2. Budget is a prime consideration 

3. Warranty is critical and important to know up front 

4. Important considerations should be given to both the costs and benefits of each choice. 

There is no one good answer. I am cheap and am fine with the AL trade offs. Most importantly, the weight savings is so minimal to me. But for some, especially if you race, it could be an advantage.

everyone is different 

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We have four sets of Enve rims and they have been nothing but reliable. The other two Reynold carbon sets came stock on our Switchblades and are also easy to mount tires and stay true. A few years ago, I had a nickel sized hole in the side of one of my older wheels from a rock strike and Enve replaced it free without hassles. The newer M50-60s don't have the bead hook, so they are even easier mounting with initial mounting pressures of 50psi (Maxxis Ikon 2.2 to Minion DHRII 2.4).

I'll take lower inertia wheelsets any day. Probably not noticeable in Enduro riding, but noticeable over a 2-3 hour XC race, especially in the mountains or accelerating out of 100-200 turns; just a factor among many to having a good race. I don't miss regularly truing wheels, breaking spokes and breaking nipples with the alloy rims.

To answer the OPs question: generally 30psi rear, 25 psi front.

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I’ve been on Nox rims i29 width for 5 years now.

I have loved these rims. I noticed the improvement first ride coming from my flow front and newer (then) flow ex rear. They stay true and hold tension as if new. They handle strikes better than al and the higher tension from offset is nice.

I have to admit the flows have improved dramatically since my last set, with exception of the flow version of MK3 from what I’ve heard.

Honestly I think well designed and manufactured carbon rims don’t save weight so much, but are stiffer (positives and negatives to this) but will stay truer, and hold tension and last longer than al. Early Al 29er rims were too flexy imho. In addition to design improvement in 29 al rims, boost probably made as big of a difference. I’m on my first set of boost (Nox again) rims and they are definitely stiffer but wheel builder took that into account and used smaller gauge spokes.

Also, re earlier posts about tire pressure- a 2.6 at same pressure you run 2.3 or 2.4 will feel like a rock. Not only do you need less pressure but the higher the volume, the more sensitive to 1-2 lb difference the tire will be.

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Got a new stans flow EX3 27.5 laced up to a Chris king hub for my pivot DH bike. I’m excited! 

Will update as time tells with pro season right around the corner 

3384CC0B-4C5D-45AE-B452-291CFD34E57A.jpeg

875BE05C-A535-4BCD-A816-BD8C36D33E7F.jpeg

Edited by Seths Pool

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So I just picked up a pair of Bontrager Line Elite 30s and I really like how stiff and light they are, but man I keep dinging the rim...I am all for straightening aluminum rims, but not every ride. I like running lower pressures especially on this bike as it is my hardtail. I run the same pressures as my FS and have had more rim strikes/dings on this bike in a month than 2 years on my squishy. The hubs are amazing since they are essentially re-badged DT 350 straight pulls, but the rims are too soft. Looking at getting them re-laced in the near future and looking for recommendations on a bomb proof rim for my hardtail ss.

May try huck Norris as well, but I have ridden Cush Core and do not like it. Willing to try carbon, but it makes me nervous as hell considering I regularly have rim strikes at my pressures. Also I like aluminum prices more as well...

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21 hours ago, csmceuen said:

So I just picked up a pair of Bontrager Line Elite 30s and I really like how stiff and light they are, but man I keep dinging the rim...I am all for straightening aluminum rims, but not every ride. I like running lower pressures especially on this bike as it is my hardtail. I run the same pressures as my FS and have had more rim strikes/dings on this bike in a month than 2 years on my squishy. The hubs are amazing since they are essentially re-badged DT 350 straight pulls, but the rims are too soft. Looking at getting them re-laced in the near future and looking for recommendations on a bomb proof rim for my hardtail ss.

May try huck Norris as well, but I have ridden Cush Core and do not like it. Willing to try carbon, but it makes me nervous as hell considering I regularly have rim strikes at my pressures. Also I like aluminum prices more as well...

Personally DT Swiss is my choice for aluminum. XM 481's can handle anything here in centex.

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