[LMN]

Still curious about my question above. Take a "typical" 420g chinese open mold 30id carbon rim and compare a 32h build vs. a 24h build.

What spoke would a 24h build need to use to be comparably stiff as a 32h build with Sapim Laser or DT Rev?

My understanding is that most modern carbon rims are so stiff that flex occurs at the hub and the only way to reduce this is to increase spoke count.

https://bikeraceinfo.com/tech/wheel-stiffness.html
http://www.aeroweenie.com/assets/backup/zipp_data/spokecount.pdf

But there is a lot pretty competent bikers out there who think that a lot our wheels have become too stiff.

 

[Kirsa]

I am exactly 91kg/200lbs and I ride XC.

I have 2 wheelsets.
Newmen Advanced SL X.A.30 for racing - 1314gr
https://www.newmen-components.de/en/83/mtb/wheels/advanced-sl-xa30/

Duke Crazy Jack SLS2 6TERS for XCO and jumping and trail riding.
1480gr, newmen fade hubs, sapim cx-ray spokes.
https://www.duke-racingwheels.com/duke-crazy-jack-sls2-6ters/?lang=en

Duke wheels look and feel very strong - I could probably ride enduro with them instead of xc/trail.

I haven't jumped with newmens just in case but they look and feel also very sturdy without any problems.

I did broke 1330gr mcfk 30mm wheels after 10 rides and some xc jumping - so I am little bit careful now.
MCFK wheels also had 125kg weight limit and they said my problems were one-off - nobody else had complained.
But they did give me money back after I told that I weigh 91kg and ride xc. In the end very good customer service but I would recommend these wheels only for lighter riders.

 

[WHALENARD]

I'm interested to hear how a 24h Berd build works as a front wheel on a mountain bike.

X2
Is there any considerable lateral stiffness difference between a wheel build with Berd spokes vs a wheel build with traditional light weight spokes like a supercomp?

I'm considering building up some lighter weight wheels over the winter 30-35mm id. Berds are very appealing due to there weight but have concerns with how they may ride. Specifically being pushed in hardpack berms by a 235 pound rider. Would a 28 hole 29'r 450G carbon rim laced with Berd's up front be less laterally stiff than a 32 hole 450G carbon rim laced with supercomps?

 

[Hoverbike]

I am 200lbs. I am an XC racer on a 120mm front fork that rides fast and ride rock gardens hard. I thought long and hard about this question too. I Ride Nox Skyline Carbon wheels with I9 Hydros hubs. I am blanking on the gauge of the spoke but they are the Sapim CX-Rays. They are fast and light. I think about 1423grams.... but they could be a few grams heavier. That is w/ tape. I hope that helps.

 

[Kirsa]

I wanted to add I wouldn't go any lighter than my current setup - 1300 for xc and 1500gr for trail. If I could choose - ideal would be something around 1400gr - with 30mm rims of course.

But I haven't yet found strong 30mm rims with weight around 380-390g mark. If there is I would probably ditch my 2 wheelset system.

 

[circuitsports]

https://us.huntbikewheels.com/colle...t-race-xc-mtb-wheelset?variant=33272433279021

 

[One Pivot]

If you have a 1300g wheelset and a 1450g wheelset, you should try swapping tires between the two. 150g of wheel is nothing. The heavier wheelset will be faster with the xc tires. 1500g is comically light. I mailed out a set of 1550g wheels recently and the UPS store guy asked me if the box was empty. It does really feel like nothing.

But nevermind all that. If you built a 1650g carbon wheelset it would feel like being shot out of a cannon compared to your rovals. They would be stiffer, handle better, and accelerate in a way that feels faster. Your times would likely improve from improved handling and confidence on a good set of wheels. Realistically those carbon wheels just happen to end up closer to 1450-1550g and I think people conflate the weight savings with what actually made the difference.

At 200lb, you can do much better than rovals but I wouldnt worry too much about the weight.

 

[Suns_PSD]

I built a set of Carbon Fan 29" wheels about a year ago. I used a DH layup in the rear, and an AM layup up front. 28mm wide in the rear, 33mm wide up front. 32H rear, 28H front. P321 hubs with Berd spokes.
They take tons of abuse and I've heard the dreaded PING! several times, do lots of drops over 5' and decent jumps, and even rode 2 hours of the Monarch Crest trail on a rear flat. They have been trued a few times.
They weigh 1370 grams. I weigh 182#s before gearing up.

 

[Suns_PSD]

We'll see soon enough, I'll post pics!

BTW my 20h front 24h rear / 45mm deep road tubless wheelset is still performing like a champ.

View attachment 1369413

About inserts, here's one that looks like it saved my bacon more than a couple of times. For guys well above 200# I'd recommend 2" inserts and 2.4" tires.

View attachment 1369415


Re: "ur logic is flawed" comments, going to pass on that, been there, done that, life is too short....

Plain and simply, you need more air pressure.

 

[chomxxo]

Plain and simply, you need more air pressure.

Thats a silly thing to say.

Just finished building these. 1270g, 30.5mm internal width. The lightest 30mm wheels in the world

They’ll be raced this weekend; I’ll let you know how it goes!

Sent from my iPhone using Tapatalk

 

[Le Duke]

How did you tension them? Or, rather, what did you use to measure tension, once you brought them up to tension?

 

[chomxxo]

I used a Park TS-1. You tension them all up to 15 (100kg), let it stretch overnight down to 12, then you can true. I also highly recommend a Park SW-15 tool with the Sapim nipples to tighten directly from the rim holes, because there’s a lot of stretching to be done as part of the build process.

Raced them last weekend and they accelerated and handled fantastic. After a comeback year it felt good to finally start feeling fast again.

Sent from my iPhone using Tapatalk

 

[Le Duke]

I mean how do you know that a 15 on the Park chart = 100kgf?

Is that info from Berd?


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[rapsac]

Still curious about my question above. Take a "typical" 420g chinese open mold 30id carbon rim and compare a 32h build vs. a 24h build.

What spoke would a 24h build need to use to be comparably stiff as a 32h build with Sapim Laser or DT Rev?

This also depends on the rim and hub (system stiffness), but if you just look at the influence of the spokes (other elements of the system assumed to have infinite stiffness = not correct, rim has significant influence to distribute loads to other/nearby spokes(*), hub not as much so) and model them as 1st order elements that have no bending/torsional stiffness (proper enough assumption) and have a continuous cross-sectional area (not correct, most spokes are butted):
(32/24 * 1.5mm^2)^0.5=1.73mm spoke diameter for same material spoke.
But alas you can not simplify it like this. But you can say that the lesser the amount of spokes, the bigger dia (larger E*A) spokes and-or stiffer the rims needs to be to (try to) reach an equal system stiffness - if at all attainable.
*: the more so with less spokes!

 

[chomxxo]

I mean how do you know that a 15 on the Park chart = 100kgf?

Is that info from Berd?


Sent from my iPhone using Tapatalk

Yes, that is in the instructions in the Berd build kit. I also got the advice on using a SW-15 from Berd support (it takes a LONG time with a conventional spoke wrench). You could even use an electric drill with a tension cutoff to speed up the work if you have the correct bit.

The number of spokes thing, you other guys are way over-thinking this: a carbon rim will be stronger with fewer spokes than aluminum. Like long stems, 32h is outdated and old school. I have a buddy who just bought some Synchros Silverton SL fully carbon wheels with bonded carbon spokes, 20h front and rear.

I am looking at an ideal Cat 1 / life balance race weight of no lower than 190 pounds, although I raced pro for a couple of years at 175. I'm about 200 now in the offseason. I know how to make the bike go fast and I had no problems with these at all, nor my previous 24/28h carbon rims for years...

If you're not as tall as me though, and I'd recommend some long rides in the offseason to shed weight as watts/kg, according to my Traininpeaks numbers, seems to be the most important thing in XC racing.

 

[rapsac]

The number of spokes thing, you other guys are way over-thinking this: a carbon rim will be stronger with fewer spokes than aluminum. Like long stems, 32h is outdated and old school. I have a buddy who just bought some Synchros Silverton SL fully carbon wheels with bonded carbon spokes, 20h front and rear.

Some people over-think, other people over-simplify or are just wrong. No problem, it’s the internet ;-)

 

[Le Duke]

Yes, that is in the instructions in the Berd build kit. I also got the advice on using a SW-15 from Berd support (it takes a LONG time with a conventional spoke wrench). You could even use an electric drill with a tension cutoff to speed up the work if you have the correct bit.

Ah. That's good to know. I was wondering how Berd would communicate that, because I haven't seen anyone post any method of measuring or converting traditional steel spoke tension measurements of kgf into Berd kdf.

 

[rod9301]

So, i read that a5 ft 8 competitive xc revert weighs 135 lbs.

What are you doing xc racing at 200?

Have you tried downhill?

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[Le Duke]

So, i read that a5 ft 8 competitive xc revert weighs 135 lbs.

What are you doing xc racing at 200?

Have you tried downhill?

Sent from my Redmi Note 8 Pro using Tapatalk

What in the world are you talking about?

 

[Kirsa]

What are you doing xc racing at 200?

Have you tried downhill?

When you live in the country where the highest peak is 318m then downhill is not really an option

And 200lbs is not so big deficit on flat tracks(they can still be very technical) or in race trying to leave your group behind into headwind.