I’m considering building some light weight wheels with some nice hubs and some of the Chinese carbon rims for trail/XC/AM riding. Apparently these rims are pretty good?

I’m thinking a DT Swiss 350 rear and Superstar Superlight front hub.

I’ve done a fair bit of reading about this already but it would be good to get the opinions of those who’ve tried it.

My main concern is that the ride could be quite harsh but I love the idea of light weight fast wheels that are potentially more durable if I look after them.

They will probably be used on a SC Heckler XC build.

If you do, just avoid alloy nipples. That will be hard/impossible though. Currently there’s problems with galvanic corrosion between carbon and alloy, the only fix being new nipples and spokes, which gets expensive if t’s £4 a pop CX-Rays!
Personally I wouldn’t touch carbon rims with a barge pole.

It depends.

I’ve got a pair. Broke one rim after 3 months. Got a replacement from the supplier – I had to pay the postage.

I think the harsh ride thing is a load of nonsense. So many other factors that make a bigger difference to the harshness of your bike’s ride.

I noticed a difference in the ride, but only that the wheels were lighter and therefore easier to throw around.

I wouldn’t recommend them for someone who routinely trashes parts.

Depends…Given that most alloy rims are under £100 each – and often under £50, the price per gram saved is very high.

Surely any refinement in ride quality can be better mitigated with a carbon bar?

Superstar were doing a brilliant deal on theirs. At that price they were worth a try. We have clattered a pair of LBs and Superstar all over this year including Verbier and Finale. Both sets have held up well but didn’t pay alot of money for either.

I found the benefits not to be so much the lower weight (depends what you were using before of course) but the additional width. The Light Bicycle 35mm and 38mm rims increase the volume and allow lower pressures. The increase in grip and general improved feel is quite marked. I haven’t noticed any harshness, especially as I am now running lower pressures anyway.

Whether they are worth it depends on your point of view, what you’re trying to achieve and exactly what you’re comparing them to .

I think like for like a carbon rim will be ~100g lighter than an aluminium rim intended for the same purpose.

The carbon rim will mostly likely be stiffer, but whether you’d notice this, and whether its a good thing is debatable.

All in all it comes down to how much extra cash the carbon rims are, but I reckon in most circumstances its marginal.

I say all this as the owner of a set of carbon rims, and a set of aluminium rims. The carbon rims are undeniably lighter,and stiffer ,and both of these differences are noticable and an improvement. But is it worth the extra cash for that lightness/stiffness – I’m not entirely sure it is.

The Light Bicycle 35mm and 38mm rims increase the volume and allow lower pressures. The increase in grip and general improved feel is quite marked. I haven’t noticed any harshness, especially as I am now running lower pressures anyway.

DT Swiss are now doing an alu rim with a 30mm internal width, so you should be able to achieve the same low pressures/increased grip with alu rims now.

Re weight. Extra strength and stiffness of a carbon rim means you can run less spokes and more tension. Suspect most people just build them up the same as alu rims and miss much of the benefit.

Syntace look to be doing some nice wide alu rims too.

For 29ers, I’d say definately.

Just pick your spoke guage carefully. I have two sets, one with heavy guage spokes and the produce quite a harsh ride.

My other set have sapim lazers and ride really nicely, just a little bit of flex.

Surely any refinement in ride quality can be better mitigated with a carbon bar?

I’m getting one of those too from China for about £15. The carbon rims are around £100 each so I’m thinking it might be worth a try. It might all explode but then again it might be awesome.

galvanic corrosion between carbon and alloy

This is a bit concerning though I shall have to look into that.

I’m currently torn between the lb 38mm or the Easton 30mm.

There’s only 35 grams difference between them and 8mm. Question is, is there a point where extra rim width becomes too much?

“, is there a point where extra rim width becomes too much?”

Fnarr, fnarr

If you do, just avoid alloy nipples. That will be hard/impossible though. Currently there’s problems with galvanic corrosion between carbon and alloy, the only fix being new nipples and spokes, which gets expensive if t’s £4 a pop CX-Rays!
Personally I wouldn’t touch carbon rims with a barge pole.

What are your findings on this issue? I’ve read up a bit about this and folk are saying ‘just use brass nipples’. I found a chart that say’s brass reacts much less with carbon and titanium much less than that.

It seems there’s a risk of corrosion if the components are touching one another or do you think there could be a risk to other alloy components like forks and frame?

Edit: You can get copper nipples too which is even less conductive than brass.

I’ve been running a pair of Roval Fattie Sl Carbon wheels for nearly a year now, bought new for 1200 quid it was expensive but the warranty is spot on & very sensible should you crack / smash a wheel.

The wheels have been absolutely mega, a week in the highlands doing Torridon and the like took its toll in scratches but nowt else, benefits are ace with being 30mm internally wide there’s added grip as the tyre profile is spread out not as rounded. Ride quality has suffered as the increase in stiffness is felt, I have a pair of DT240 hubs on KOM rims and I’d prefer them on a long all day ride but performance on the fatties is very noticeable as they just roll so fast, not a single pinch flat or tyre issue, they inflate very easy, perhaps a little tight to initially get on the rim, Pink bike did a good review on them & Roval did a lot of testing to show that past 30mm the gains are out weighted & become negligible also frame width starts to become a issue as the tyres do get noticeable wider & can rub on the frame though that’s on standard 650B not plus frames.

Currently there’s problems with galvanic corrosion between carbon and alloy

Does this still apply to an anodised nipple though?

I built mine with a dab of grease applied to the nipple rim interface too, not wholly convinced it’s a real problem.

Plus doesn’t depend on the epoxy used too?

I think it’s too big of a sweeping statement. I’ll check on mine in a years time.

Carbon rims, worth it? If you want a bike that’s as light as possible it pedals really well, then yes, the strength and stiffness to weight ratio cannot be matched with aluminium, it’s very perceivable on the bike. A gravity bike or a bike for a bit of pootling, no.

I’d say the harshness is definitely there, i can’t work around it with lowering the pressure either, already at the point of almost burping at 28ish psi, low 20s ain’t an option.

Just got a Ripley 3 with the Ibis 941 rims so will let you know. Feel very stiff, but then its complicated as the tyres are being currently run at 20/23 psi front/rear with this dropping slowly towards 18/21 as I get feel for them and the probability of rim strikes from rocks. But the profile on the 41 mm (35 mm inner) rims make the tyres look really fat and wide.

A bit worried as I do like to lob not rock gardens but if Gary Forrester (I bis UK rider)can run them on his Ripley at 20/22 then i should be fine

Been running some Nextie carbon rims since last January – particularly beneficial when running plus size tyres tubeless as the bigger carcass protects the rim more. I wouldn’t bother with alloy nipples – negligible weight saving and problems with corrosion – not just galvanic, but stress-corrosion too plus rounding a nipple is a PIA to fix.

I’m in the same boat as Onzadog, though I’m looking at the DT Swiss XM481 rims.

carbon wheels, awesome upgrade. Tough light and stiff

Very pleased with mine- did break one but it had a long and hard life so it’s perfectly reasonable tbh. And got a discount on a replacement from Lightbicycle despite it being out of warranty and in any case not a warranty matter. Pair on the 26er were great, tougher ime than a pair of flow exes so I’ve put my money where my mouth is and got another set for the 29er.

There does seem to be some seriously good alu options coming out now too, though.

Re corrosion – the spoke hole is drilled so there is exposed carbon. Annodising could/should help a bit but as you tighten the spoke by turning the nipple you are scratching this protective layer. Also you don’t need to be actually touching provided there is an electrolyte or other conductive medium to do that for you and water mixed with salts from mud will do that quite nicely. Epoxy has no effect tbh.

Re weight saving – try making a 30mm internal width 29er rim for under 400g that can take abuse. I have no problem admitting I don’t like epoxy based composites due to sustainability (or lack of) but you can’t get aluminium to compete in this area and weight in wheels is probably the best place to save it.

Re nipples – brass would be my choice. Stainless and titanium have galling problems. Alloy is just too susceptible to corrosion in wet environments before you even add the carbon into the mix. Just look at an old alloy frame or alloy wheels where the lacquer has got water inside. Copper – that would be a bit silly as it’s very soft and much better when in an alloy…ie brass…Don’t forget brass is one of the original marine metals of choice for a reason. It might be a bit heavy but it really is grams over a wheel.

Was just reading through that enve article on the front page and tbh in my opinion their manufacturing procedures do not match the high price they charge. Article was pretty badly informed too…

I’m a bit biased as I’m sponsored by ENVE(on King/cx Ray)but on a 29r there is a massive difference pushing hard through rocky sections.

If you do, just avoid alloy nipples. That will be hard/impossible though. Currently there’s problems with galvanic corrosion between carbon and alloy, the only fix being new nipples and spokes, which gets expensive if t’s £4 a pop CX-Rays!
Personally I wouldn’t touch carbon rims with a barge pole.

I run alu nips in mine, they’ve not exploded. Bit of a non-issue IMO, but why would you need new spokes to remedy that, and why will it be “hard/impossible” on custom built wheels?! Worst case you’ll have to try and get a few swipes nipples off spokes. Alu tend to crumble anyway once they reach that stage.

Alu nips are more fragile anyway, I’d not bother unless I was worried about weight specifically. Brass are a more sensible choice all round.

Thanks folks. It seems that rims are getting a lot wider, I’m quite out of touch!

I read somewhere that having lighter spokes on a carbon wheel is good to promote a bit more spring in the wheel as well.

Re corrosion –

In a typical MTB application (not much commuting/road), things will get wet, but not necessarily salty, unless i’m way off the mark when it comes to galvanic corrosion, the conditions aren’t ideal for galvanic corrosion.

Will the carbon be compromised enough to lose much strength around the spoke hole?

Would the corrosion rates be great enough on the nipple that the head can become eroded to enough depth to fail?

How long of a life does a typical carbon wheel buying consumer realistically want in a carbon wheel? I’d be happy with 2 years, is this enough time for the corrosion to be an issue?

I’m currently torn between the lb 38mm or the Easton 30mm

Easton are 30mm internal, LB 38mm external. The actual internal with difference is only 1.6mm, not 8.

Been running some 30mm external Light Bikes rims for 8 months now on my main MTB, and I’ve been thoroughly impressed. They’re almost comically light, my 30mm 29er rims (they’re 24mm internal) were about 380g each, and built into DT240S hubs with Sapim DeLite spokes they weigh bang on 1500g for the pair before tape and valves! When you consider that I’ve taken these wheels down all the black runs at Bike Park Wales on my full sus and I wasn’t being careful, they’ve shrugged everything off I could have thrown at them. The only thing I’d change them for is a wider version to give the tyres on my FS a broader profile.

Have also been running some Reynolds Assaults on my road bike for the last 8 months too, and they transformed it. So light, so stiff, and yet with the aero benefits a deep carbon rim brings too.

However… I will say that for 26″ and even 650b, the advantages of carbon rims are diminished enough to make them a lot less of a performance improvement. Shorter spokes make for a stiffer wheel anyway, so on 29ers and road bikes the added stiffness of a carbon rim makes a significant difference over an alloy one. On a 26″ or 650b MTB, I simply wouldn’t bother…

Re corrosion –

In a typical MTB application (not much commuting/road), things will get wet, but not necessarily salty, unless i’m way off the mark when it comes to galvanic corrosion, the conditions aren’t ideal for galvanic corrosion.

‘salts’ are everywhere. As I said “salts from mud” – mud will contain all sorts of minerals, think about what happens to rocks when they are eroded by water and where it ends up and don’t forget animal pee and poop etc etc. We don’t notice it as bad though as the effect of the salt we put on roads is extreme and silly IMO

Will the carbon be compromised enough to lose much strength around the spoke hole? not really. It’s bloody strong, even with a hole in it. But do the hole wrong or use the wrong shaped thing in the hole…but that can be said for thin wall metals too, especially when as soft as aluminium.

Would the corrosion rates be great enough on the nipple that the head can become eroded to enough depth to fail? When things oxidise they expand – so there is a risk of damage to the spoke hole from the expanding metal and there is a risk eventually of the head crumbling if you allow water inside the rim (it will get in there somehow). The big problem tends to be corrosion in the spoke thread causing them to seize and then no more wheel truing.

How long of a life does a typical carbon wheel buying consumer realistically want in a carbon wheel? I’d be happy with 2 years, is this enough time for the corrosion to be an issue? You are a bike part sellers dream then 😉 If not raced or used in very hard riding then there is no reason why a carbon rim won’t last 5-10 years, same as any other rim. 2nd hand value won’t reflect that though due to people being wary of composites but if they are your wheels and you know how they have been treated and it has been well then no reason they shouldnt last a long time, abuse, accidents etc aside

answers in bold

What are your findings on this issue? I’ve read up a bit about this and folk are saying ‘just use brass nipples’. I found a chart that say’s brass reacts much less with carbon and titanium much less than that.

Correct. Brass doesn’t react, the problem is the nipple, not the rim. Specifically it’s when unfinished carbon is in contact with bare aluminium. Google galvanic corrosion, it’s just a fact, something that happens. I’ve seen it first hand on Enve rims with their supplied nipples. There is even a brass nipple available for Enve rims HERE
It is a problem, not every wheel will do it, but it’s not uncommon, and it’s well documented. CLICKY

Will the carbon be compromised enough to lose much strength around the spoke hole?

No. The carbon is the boss in this chemical reaction. It’ll be fine.

Would the corrosion rates be great enough on the nipple that the head can become eroded to enough depth to fail?

Yes. The nipples literally fall apart inside the rim. I’ve seen it, and I’ve shaken the bits out onto the floor.

Carbon vs aluminium does this:

[url=https://flic.kr/p/dSZmbJ]IMG_1443[/url] by Peter Atkin, on Flickr

that’s my own seatpost from my own carbon frame. This doesn’t happen all then time, but if the internals of a carbon frame or rim are unfinished bare carbon, be aware, and don’t chance it. That’s what I’m saying.

^Peterpoddy seatpost is going to a pretty extreme example though, large surface area, unfinished carbon, dammage to the seatpost when inserted and a constant supply of muck to dribble down into it.

answers in bold

Cheers, always good to read info.

I’m more than happy to take the risk on the alu nips, a fresh rebuild isn’t the worst thing in the world. It’s also nice starting fresh with new spokes anyway after a long while, routine tweaks become a pain after a long while.

Galvanic corrosion happens irrespective of the presence of salts.

Ok, maybe not salts per-say, but you need a electrolytic medium, right? Migration of ions and all that.

(someone fumbling through this trying to get it sorted in their head).

For sure, just don’t get to hung up on salts.

Where’s Heisenberg when you need him?

Purely psychological for me.

My brain would just tend to dwell on their perceived “weakness” while I’m riding and I just don’t enjoy that during a ride.

That’s just me though. 😀

http://singletrackworld.com/forum/topic/carbon-rims-alu-nipples

Just use brass nipples

Ah, just twigged, the 35 vs 38mm (external) lb rims are more about thicker walls than wider footprint.

I have some AM LB rims.. I really like them, the difference is subtle, but always there, they wind up fast, steer much more positive, especially sudden changes of direction and feel better when leaning, although the leaning may be because they are a tad wider than the rims they replaced.

I think people have issues with breakages are not taking into account thier riding style.. Carbon wheels like for like are much tougher.. But not indestructible.. Issues occur when for example a down hill rider specs up xc rims with 28 spokes. Slight exaggeration but I’m sure you get my analogy.

I ride mainly XC, weigh 95kg..lb suggested a 32 spoke count and hookless AM spec rim.. I doubt I’ll ever be able to break them. The AM spec is thicker built than the XC spec, but lighter than the DH spec. They are not massively lighter than my crappy ally rims they replaced, but they are a shed load stiffer. I have absolutely no concerns about them, they looked and felt good out of the box, and since riding them I can only think of plus points, other than the price, lol.

If you already have high end alloy rims and good hubs I don’t think the difference would be so pronounced.