CX-Rays. All I use anymore.
Anyone running $178 chinese carbon rims for DH yet? light-bicycle.com
- Thread starter thad
- Start date
Tire and pressure? All three had cracked sidewalls from impacts?
At what point do you just say f-it and go back to aluminum rims?
First tire was a WTB vigilante team issue. Pretty stout tire but I made the mistake of setting the tire with dishwashing liquid the night before and I think it pushed off the bead in a corner because the soap was still wet. There were a load of rocks after that for my naked rim to roll through at 30 mph... Next was a maxxis EXO DHR2. I blame that on the thin tyre. Actually broke the rim in 2 places. The last one was on the double casing maxxis aggressor and that's got me stumped. All at 31-32 psi and all cracked at sidewall from impact. To the rims credit (after some duct tape to protect the sidewall on the EXO break), I rode out every time.
The thought has crossed my mind this last time. The first rim lasted 18 months without buckling or denting, which is better than I can get out of any similar or even slightly heavier aluminum rim. The first 2 breaks I kind of blame myself. This last one has me wondering. Hopefully the dh layup makes the difference and I get the 18 month lifespan, not the 3. We'll see.
Yeah, break 3 is puzzling. Since switching from Exos to WTB Tough casings I've been able to run 23frt, 27rr with no rim damage.
The 2.5" Breakouts are BIG and the casing feels thick. I up the psi to 24/28 for particularly high speed, rocky tracks like Keystone but the point is I'm running WAY less pressure than with Maxxis 2.4/2.5 Exo tires.
There was that one rocky spot on one of these, either TNT or PIF, where I would flat the rental bike each time I tried it at full speed, it had a skinny 2.3 minion out back and while I felt like the traction was adequate, it just wasn't big enough for riding that abusive and hard. It was like a rocky old logging road or something where you could pop off a few things at speed and then land in a pile of rocks. Tubes were part of it, no doubt, but to get decent traction on edge, it took pressures that got rim strikes. I've never really been able to run less than a 2.5 rear in really aggressive chunky terrain DH, but I know lots of people do it.
That section took out a LOT of people the first two years they had a national enduro at Keystone, including putting slow leak right in the center of my 2.4 HRII Exo so I had to gradually take it easier and easier on the lower sections. This year they smoothed it out and it was SCARY to race on! Crazy fast, cuz if you remember it's kinda steep, and they put a few long low table tops in that were a little kicky at race pace. I missed the sketchy rock gardens that flatted out some of the competition.
Yeah I hear ya but If you check further down the article you'll see he is running aluminum dh rims. I'm sure he doesn't mind a few flat spots if he can maybe win a race, being sponsored and all. Might be running super gravity schwalbe too.... You're right though that my psi is higher than most. I checked with some friends today and they are running less. A guy on Enve wheels says he often feels the rim strike but has not had an issue with any damage. Maybe I've just messed up a couple and the last was a dud.
When I get my new rims I'll have another crack at it
Err, that was bad I.N.T.E.L.L.I.G.E.N.C.E. Very bad I.N.T.E.L.L.I.G.E.N.C.E.
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Doesn't mention if he's running procore either.Yeah I hear ya but If you check further down the article you'll see he is running aluminum dh rims. I'm sure he doesn't mind a few flat spots if he can maybe win a race, being sponsored and all. Might be running super gravity schwalbe too.... You're right though that my psi is higher than most. I checked with some friends today and they are running less. A guy on Enve wheels says he often feels the rim strike but has not had an issue with any damage. Maybe I've just messed up a couple and the last was a dud.
When I get my new rims I'll have another crack at it
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I should post an update that I eventually bought the LB AM728 Asym rims, 28mm internal width, 34mm external width. It took a while to get them built up, and I just got them mounted on my bike Friday but due to rain haven't ridden them yet. I'm excited to see how they feel on the trail.
The rims look really good, no visible quality issues or any problems during the wheel build. I measured ERD myself because the given number does not account for the nipple. I used Hadley hubs, Wheelsmith DB spokes and Sapim alloy nipples. This combo allowed me to use one spoke length everywhere which was nice. I had a local shop do the final tensioning and truing.
The rims look really good, no visible quality issues or any problems during the wheel build. I measured ERD myself because the given number does not account for the nipple. I used Hadley hubs, Wheelsmith DB spokes and Sapim alloy nipples. This combo allowed me to use one spoke length everywhere which was nice. I had a local shop do the final tensioning and truing.
You still like those spokes? A rear wheel I built with Sapim Lasers 2 1/2 years ago is getting old on me, I break a spoke every few weeks. I am rebuilding it with CX-Rays soon.
Nice wheel, I am still not convinced that carbon rim + alloy nipples is a good decision. Galvanic corrosion is a biatch.
Somehow I broke a spoke today. Since I built my 35mm nexties with alloy nipples, I figured it was the ole broken spoke head, although it's kinda early for that. Looking closer, the spoke broke right above the threads, which is crazy IMO, I'm not sure how, but the rims are so rigid I don't mind finishing a ride like that and easy enough to fix. Comp spokes I think, possibly supercomp.
It is definitely a bad decision. I got my new-ish LB wheel built up with brass and am going to have my front rebuilt that way.
Yeah, some of the early Enve wheels used Al nipples, and the nipples would just disintegrate after a few years. They're brass now.
I'm still a big fan of CX-Rays. Quite a bit cheaper than Aerolites and when I tried the Pillar version (1420s) I broke a few.
Thanks, I'll see how it works out. The anodize on the nipples should help mitigate corrosion and I used grease on the nipple seats as well. It seemed like plenty of builders are using alloy nipples with carbon rims and I didn't read about too many issues.
I thought of using CX-ray spokes, but at $3 each that was getting to be too much cost per gram saved. The Sapim D-Light seems like a really nice spoke as well, but harder to find.
dans comp has the best prices on sapim spokes.
do they actually sell them in lengths suitable for a mountain bike wheel?
not confidence inspiring:
https://www.danscomp.com/products/435029/Sapim_CX-Ray_Bladed_Spoke.html
apparently white, no length listed.
i bought them in black and 292mm, which is 29er lengf. you just have to call. paid like .75 a spoke or something? great service.
it looks like they changed their catalog recently. maybe they got rid of them? maybe they simply fucked up their catalog.
if you read the pages for sapim you have to call to order.
here it is:
https://www.danscomp.com/products-PARTS/435920/Sapim_Double_Butted_Spoke_(Black).html
https://www.danscomp.com/products-PARTS/435930/Sapim_CX-Ray_Bladed_Spoke.html
You do have to call to order, in order to confirm the legnth that you want. Presumably they cut them to order, but mine were/are perfect.
https://www.danscomp.com/products-PARTS/435920/Sapim_Double_Butted_Spoke_(Black).html
https://www.danscomp.com/products-PARTS/435930/Sapim_CX-Ray_Bladed_Spoke.html
You do have to call to order, in order to confirm the legnth that you want. Presumably they cut them to order, but mine were/are perfect.
Bladed spokes usually don't leave room for much length variation/cutting.
$1.75 is a lot more reasonable than $3/spoke! Bike industry prices make you scratch you head sometimes.
same w/ butted spokes.
Except that most are butted at the head, not the threads.
have you ever been to a bike shop?
I don't know if your daft or just taking the piss, but more etailers sell pre-cut spokes at even lengths. few custom cut to order. Prowheelbuilder is one, and cambriabike does as well, but theirs seem to be cut spokes in pre-determined length. So Dan's is one of two, by my measure, that cut your spoke to exactly the length that you request. Of course your bike shop will as well, if they have a $15k phil wood spoke cutter, and you want to pay $3 a spoke plus labor to cut them.
So, Dan's is pretty unique in that they custom cut your spokes to order. Big shout out to cycle loft in Burlington, MA though, they cut some straight pull spokes for me for free back in the day. Best shop for service in the boston area.
Mine were cut post-butt with some room to spare. I'm guessing that they have a variety of lengths that leave a little room for shortening. The cuts aren't perfect, but my admittedly amateur wheels went together great!
that's my point. by and far the vast majority of spokes are pre-cut. cutting and threading spokes is probably about the only thing that bike mechanics hate more than press FIT bb's.
not saying that DB spokes can't be cut, but there's limited room for change.