Wheelbuilders of ST: Advice for an XC Wheel Build

Nov 1, 17 13:55

Post #1 of 21 (3143 views)

Bike: full suspension 100mm
Rider weight: 170lbs
Riding: mostly smooth single track, occasional root-infested course, no downhill bombing (I'm a wimp when it comes to such ventures)

I'm building up a set of carbon hoops and I'd like to add power as well so I want to build the wheels up with a Powertap disc brake rear hub. Questions:

Should I go with a 24 or a 28 spoke build? I'm leaning toward a 28 spoke build but, considering how often I see 32 spoke spoke wheels, should I be worried about durability?
Internal or external nipples? In my understanding it's a tradeoff between having to true a wheel and wheel strength.
Brass or alloy nipples? Is brass worth the extra bit of weight?

Thanks.

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 1, 17 17:58

Post #2 of 21 (3102 views)

1. Your bike has disc brakes right ..... 24 spokes is probably going to be too little especially at your hefty-ish weight and assuming from the 100mm travel that you're on a 29er. Go for the higher spoke count using DT Rev or Sapim Laser spokes. It won't be a huge weight penalty, and you'll have peace of mind that you won't taco your wheel on a hard brake/turn and won't have to constantly be having to make truing adjustments.

2. External nipples all the way. With the MTB you'll actually need to true your wheels once in awhile if you hit gnarly stuff, and its not worth the inconvenience of having to take your tire off, especially if you're (should be) running tubeless.

3. The plus side of alloy is that you can get them in cool colors. Brass usually preferred for strength if you're running high spoke tension

Last edited by: Sim: Nov 1, 17 18:00

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [Sim] [ In reply to ]

Nov 1, 17 19:31

Post #3 of 21 (3079 views)

Ok, so 28 spoke, external brass nipples. I see a lot of rims have asymmetrical designs. Any need to use one of those in an FS-i where (I think) the bracing angle is symmetrical on both the drive and the non-drive side?

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 1, 17 20:12

Post #4 of 21 (3071 views)

No.

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 2, 17 4:20

Post #5 of 21 (3023 views)

Second on the no. You'll have pedaling force from the drive side and braking force from the rotor side, so symmetry is good. Just make sure that for drive and non-drive side, that the spokes pulling in the correct directions.

Last edited by: Sim: Nov 2, 17 4:21

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 2, 17 7:51

Post #6 of 21 (2968 views)

going back to your original question.

I do a fair amount of XC training and racing (although less the last couple of years).

My general advice in this situation is to just use a rim that you don't mind replacing. Aluminum XC rims are pretty nice now. And when you screw up and brake the rim, it is nice to only spend $70-100 to replace it (around here it is about $200 for a full rebuild including parts -- spokes, nipples, rims). The new Stan's Crest MK3 is very light. Stiff enough. And easy to replace when you break it.

I tend to think of XC racing rims as wear parts.

so:

1. 28 is fine. I ride 32, but 28 is fine
2. OMG, external! You want to be able to true this wheel. I'm a bit lighter, but it sounds like more aggressive, than you and I find myself truing or retensioning my XC rims 4-5 times per year.
3. Doesn't really matter. Brass are definitely more durable, but if you are reasonably handy, replacing a broken nipple is a 5 minute job.

Andy

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 2, 17 8:07

Post #7 of 21 (2961 views)

GreenPlease wrote:

Ok, so 28 spoke, external brass nipples. I see a lot of rims have asymmetrical designs. Any need to use one of those in an FS-i where (I think) the bracing angle is symmetrical on both the drive and the non-drive side?

See if you can get your hands on the installation guide for the PowerTap Hub. PT Hubs don't always work like normal hubs and sometimes need to be laced in a specific way. I know on my road bike the drive torque comes through the non-drive side of the hub. The wheel builder originally built the wheel straight on the non-drive side and had to rebuild it when i pointed out that such a build voided the PT warranty.

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [torrey] [ In reply to ]

Nov 2, 17 8:13

Post #8 of 21 (2955 views)

Good point! BUT - no one worth their salt should be building an MTB wheel with radial spoke patterns on the nondrive side (the disk brake rotor is on the non drive side and warrants some crossing of the spokes....usually 3x is best)

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [Testament TN] [ In reply to ]

Nov 2, 17 8:22

Post #9 of 21 (2950 views)

Well sure. Like I said, just find the installation manual for that specific Hub. I don't know how the disc brake PT Hubs work.

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 2, 17 8:36

Post #10 of 21 (2940 views)

Crank based PM. Powertaps have a 160mm rotor. Bigger rotors are much better at heat dissipation.
Shimano or DT hubs, Hope if you want to splurge.
32h, 3x
30mm wide rim.

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 2, 17 8:39

Post #11 of 21 (2937 views)

28.

External.

Brass is worth the weight if you're going to keep the wheels around for a bit. Alloy is an easy weight weenie choice. Brass on rear drive side and alloy on the rest is a good compromise.

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [__Tron__] [ In reply to ]

Nov 2, 17 10:03

Post #12 of 21 (2904 views)

__Tron__ wrote:

Crank based PM. Powertaps have a 160mm rotor. Bigger rotors are much better at heat dissipation.
Shimano or DT hubs, Hope if you want to splurge.
32h, 3x
30mm wide rim.

160mm rotor is perfectly fine for a XC rear wheel.

http://bikeblather.blogspot.com/

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [__Tron__] [ In reply to ]

Nov 2, 17 10:16

Post #13 of 21 (2894 views)

__Tron__ wrote:

Crank based PM. Powertaps have a 160mm rotor. Bigger rotors are much better at heat dissipation.
Shimano or DT hubs, Hope if you want to splurge.
32h, 3x
30mm wide rim.

I can't find a crank or spider based PM that will properly work with a Cannondale "SI" rear end (it's a strange beast).

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [AndyPeterson] [ In reply to ]

Nov 2, 17 10:20

Post #14 of 21 (2892 views)

AndyPeterson wrote:

going back to your original question.

I do a fair amount of XC training and racing (although less the last couple of years).

My general advice in this situation is to just use a rim that you don't mind replacing. Aluminum XC rims are pretty nice now. And when you screw up and brake the rim, it is nice to only spend $70-100 to replace it (around here it is about $200 for a full rebuild including parts -- spokes, nipples, rims). The new Stan's Crest MK3 is very light. Stiff enough. And easy to replace when you break it.

I tend to think of XC racing rims as wear parts.

so:

1. 28 is fine. I ride 32, but 28 is fine
2. OMG, external! You want to be able to true this wheel. I'm a bit lighter, but it sounds like more aggressive, than you and I find myself truing or retensioning my XC rims 4-5 times per year.
3. Doesn't really matter. Brass are definitely more durable, but if you are reasonably handy, replacing a broken nipple is a 5 minute job.

Andy

Ok, let's talk about the aluminum option for a second. I've noticed there's really not much of a difference between something like the Stan's Crest MK3 and most of the carbon rims on the market (granted most of them are wider). My stock rims are Mavic Crossmax Pros which are pretty dang nice to be honest with the bonus of not needing rim tape. Do you think I could have the rear wheel rebuilt with a Powertap hub? Or is that a question for someone like Wheelbuilder.com?

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 2, 17 11:30

Post #15 of 21 (2883 views)

I think the crossmax pros have a proprietary spoke...at least certain models (newer alloy variants), that won’t lace through PT hub.

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [Testament TN] [ In reply to ]

Nov 2, 17 11:45

Post #16 of 21 (2876 views)

Ah, gotcha :(

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 2, 17 12:09

Post #17 of 21 (2867 views)

the crest comes in a 28h and works fine with the powertap hub

as far as carbon vs aluminum, I don't think the differences are worth the cost unless going very wide. I had a set of the Enve XC rims for a while. They looked cool and were definitely stiffer than my alloy rims. But I don't think it is worth the cost for something you are going to bang up.

If you really want carbon, or want to go crazy wide, look at the Derby rims. I know a few folks on the Derby XC who like them. And supposedly they are pretty durable.

Wheelbuilder could do either. And so could your local shop.

Andy

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 2, 17 20:56

Post #18 of 21 (2821 views)

GreenPlease wrote:

Bike: full suspension 100mm
Rider weight: 170lbs
Riding: mostly smooth single track, occasional root-infested course, no downhill bombing (I'm a wimp when it comes to such ventures)

I'm building up a set of carbon hoops and I'd like to add power as well so I want to build the wheels up with a Powertap disc brake rear hub. Questions:

Should I go with a 24 or a 28 spoke build? I'm leaning toward a 28 spoke build but, considering how often I see 32 spoke spoke wheels, should I be worried about durability?
Internal or external nipples? In my understanding it's a tradeoff between having to true a wheel and wheel strength.
Brass or alloy nipples? Is brass worth the extra bit of weight?

Thanks.

I have ridden mt bike for 20 years. First off, your gonna go down, it just happens. Carbon wheels on a Mt bike are begging to get destroyed. I would not get them unless you don’t care about money.

I would say to build some Stan’s rims up with whatever hubs you choose. Also, power is basically useless in my mind as mt bike fluctuates so much. You can learn to ride more efficient and be faster. Choosing where to pedal hard and when to recover. When to not brake and flowing through the trail. I would say standard 3 cross and brass nipples with double butted spokes make for the strongest wheels. I have had aluminum nipples and while they were not bad, they are not worth the weight savings as they can strip when trying wheels. Build up wheels and use linseed oil on the spoke threads as a threadlocker. I also build wheels using a Park spoke tension tool.

Any wheel I built and rode has always stayed straight. Not saying I am a pro, but just saying! Lol

Good luck.

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 3, 17 7:02

Post #19 of 21 (2777 views)

Curious as to why you want a power meter for your mountain bike?

I strongly suggest going with stronger, wider, stouter and easier to true when selecting a mountain bike wheel. There are better places to shave weight from your mountain bike than your wheels - seatpost, stem, bars, crankset, saddle, grips, etc.

I weigh about 30 lbs more than you and have been happy with Stan's Arch EX rims set up tubeless. If building a new wheelset today I would use the newest version of the wider and stronger Stan's Flow rims.

Good luck.

David K

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [DavidK] [ In reply to ]

Nov 3, 17 7:16

Post #20 of 21 (2772 views)

For me it's not so much about "riding with power" as it is about tracking my efforts during training.

Re: Wheelbuilders of ST: Advice for an XC Wheel Build [GreenPlease] [ In reply to ]

Nov 3, 17 7:39

Post #21 of 21 (2765 views)

If I was to add power to my MTB for tracking I would likely find a stages (I know, don't beat me up about that).

But...I've been uploading to training peaks and they give me a TSS based on HR and that's really good enough for the tracking purpose.

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