# Pacenti Rim Choice - SL25 or CL25 for cyclocross?



## twiggy (Mar 23, 2004)

Hey all,
I'm trying to make a decision on a wheel build for my cyclocross bike and I'm looking for advice in choosing between Pacenti SL25 and CL25 wheels for the build.

I'm 163-170lbs and I'll be using the wheels for CX racing and the occasional (maybe once a year) gravel grinder race on my Disk-brake equipped Giant TCX advanced. I should mention that I do plan to run these wheels tubeless during race season. This is my only disc-brake bike (other than my MTB) so these wheels won't be getting a ton of road use, although I will be likely doing some training on this bike in the late winter/early spring when our roads are a snowy mess.

I originally was planning on having these wheels built up with Pacenti SL25 rims and a 28/28 spoke count. Talking to the builder, he asked if I had considered the CL25 rim - he said they're 25g lighter/rim, $15/rim cheaper, and he touted the eyelets as making them ideal for a light weight CX bike. 

Now I can't decide which rim I should go with, and I don't have any experience to sway me either way....I like the aesthetics of the SL25 but I'm not too sure either way.

Does anyone have any experience who could lend an opinion on which one to go with? Am I wise to stick with the 28/28 spoke count or could I get away with a 24/28?


Thanks!
Andrew


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## ergott (Feb 26, 2006)

Both choices will work.

That said, the SL25 is a stiffer rim and might clear muck just a little better due to its profile. The CL25 has eyelets as you noted and will be harder to clean them out after a muddy race.

With the SL25 I would be more inclined to go with a 24 spoke wheel so there's your equalizer as far as rim weight difference.


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## robt57 (Jul 23, 2011)

Yeah, the CL is a little lighter, but looks likely to hold more mud as to be heavier potentially. I have a 28 hole CL25 Set and a 32 hole SL25 set. With road tires the CL25 seem snappier, that is about the only difference. Except the CL25 is cheaper too..


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## Roland44 (Mar 21, 2013)

ergott said:


> Both choices will work.
> 
> That said, the SL25 is a stiffer rim and might clear muck just a little better due to its profile. The CL25 has eyelets as you noted and will be harder to clean them out after a muddy race.
> 
> With the SL25 I would be more inclined to go with a 24 spoke wheel so there's your equalizer as far as rim weight difference.


Exactly, you really can't go wrong with either of the 2. That being said, I would personally go with the SL25.


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## twiggy (Mar 23, 2004)

Dangit, I keep going back and forth  ...I've already stopped myself from calling my wheelbuilder twice today! I was prepared to call him this morning to say the 24/28 SL25 build but I waited instead... then I changed my mind to a 28/28 CL25 build, picked up the phone to call him then I got cold feet and decided to wait until tomorrow to make up my mind. 

I know it probably doesn't matter much either way...I just overthink everything.


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## robt57 (Jul 23, 2011)

twiggy said:


> Dangit, I keep going back and forth  ...I've already stopped myself from calling my wheelbuilder twice today! I was prepared to call him this morning to say the 24/28 SL25 build but I waited instead... then I changed my mind to a 28/28 CL25 build, picked up the phone to call him then I got cold feet and decided to wait until tomorrow to make up my mind.
> 
> I know it probably doesn't matter much either way...I just overthink everything.



Go by looks then. Or do both like I did.  But I personally would not do a 24 spoke front disc wheel unless I was 115 lbs.  I am 210-15, and I actually took one short ride on the CL25 28 hole set laced 2x and re-laced the front disc side 3x.

Which looks better on my All Road Gravel bike to you?


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## twiggy (Mar 23, 2004)

Thanks! That helps actually  haha.

Maybe you're right on staying with the 28/28.... Did you take any actual weights of the rims before building? I suppose a difference of 25g/rim is pretty much negligible....

btw - how do you like the Avid HSX rotors? I'm thinking I might try a set of those with my TRP spyres on whatever wheels I end up building!


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## robt57 (Jul 23, 2011)

twiggy said:


> Did you take any actual weights of the rims before building? I suppose a difference of 25g/rim is pretty much negligible....


Nah... The CL25 are CX75 hubs and the SL25 I got some NOS new XTR hubs for. The CL25 28h set is all Race Sapims, the SL25 32h set are more interesting spoke wise. Something I wanted to try that I am happy with. I won't tell you until after you order yours, it will just make you do more thinking... 



> btw - how do you like the Avid HSX rotors? I'm thinking I might try a set of those with my TRP spyres on whatever wheels I end up building!


Only a few rides since I put them on, since I built the new bike. I had those both wheelset on the Disc Roubiax that got replaced with the Green machine. I had SLX Ice tech 160s and Spyre SLCs. Now I have HY/RD and a 180 up front with the Avids, too much different to really guess at what changed what between the differences of the two et ups.


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## November Dave (Dec 7, 2011)

I've built a couple of CL25s and a ton of SL25s, and agree with Ergott's assessment. Either will work, but I prefer the SL25. I don't love the eyelets in the CL25, and the SL25 is a little bit more robust. The tubeless interface on both is the same.

As to lacing, I've been giving SL25s absolutely improbable beatings the last few weeks in tubeless cx tire testing. Just absolutely abusing them in stupid ways, and they haven't put a foot wrong. I certainly respect robt57's experience with regard to front lacing, but at my weight (call it 160) I've got just heaps of confidence in 24 front lacing for road and cx. But far be it from me to talk someone into a lower spoke count.

We're on Maxxis and Hutchinson tires, our other tester is a little lighter than me, we both run 22f/25r for pressure. I'm ill-inclined to speak in absolutes like "you CAN'T burp them," but I sure haven't been able to, nor has our other tester, who is a much better and more aggressive cx rider than me. We'll start using some Vittorias and maybe some WTBs soon. Thus far, we've eliminated Clement, Challenge, Schwalbe, Kenda, and Michelin as tubeless options. We're incredibly impressed with how well the Maxxis and Hutchinson tires work.


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## robt57 (Jul 23, 2011)

I miss my Buell Lightning front brake. 


Have you guys tried the Nano 40 TCS on the either SL25 or CL25s??


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## November Dave (Dec 7, 2011)

Us? Nope. We've tried and rejected Kenda, Schwalbe, Challenge, Clement, and Michelin. Kenda is almost a winner, and the Stan's team uses them successfully, and I used them last year with good results, but we found certain instances in which it was easy to burp them. The rest burped easily. Testing bigger than CX width (call that ~35mm) isn't on the agenda for now. CX is a tougher test of tubeless than anything we've yet found.

The ones that are top of the pile right now are Maxxis Tubeless and Hutchinson Tubeless. There is an excellent permanent cross trail setup local to me, on which there is a steep and loose climb with granite steps/waterbars. I did repeats up that thing for about 15 minutes. Had I used tubed tires, I'd have had about 40 pinch flats. I think if I'd used tubulars, I'd probably have flatted several times. With Hutchinson Toro Tubeless, I was able to dent the living crap out of the rim, which categorically SHOULD have happened. I was going up this thing at ramming speed, heading straight at the steps to see just how dumb I could be and have the wheel and tire survive. I never burped or flatted. The abuse that thing took was nothing short of shocking.


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## twiggy (Mar 23, 2004)

Thanks for that! After thinking last night that I would go with the CL25s I believe I've now changed back in favor of the SL25s!.... hopefully I can keep from flip-flopping between now and when the builder's shop opens again tomorrow morning!  

I assume when it comes to nipples you'd recommend brass for sure? Thats my gut feeling, but I'd been tempted to give the wheels some glitzy blue sapim alloy nipples as these are my race wheels....maybe not?

Also had a question about your tubeless attempts - when you say you tried Schwalbe with bad luck.... were those tubeless ready Schwalbes? I have a basically new set of "Super Swans" (OEM version of the Rocket Ron that came on my Giant TCX) that are "tubeless-ready"...I had been thinking I'd try those on whatever wheels I end up building!....And are you experimenting with Stans/Pacenti tape or a full rubber strip?




November Dave said:


> I've built a couple of CL25s and a ton of SL25s, and agree with Ergott's assessment. Either will work, but I prefer the SL25. I don't love the eyelets in the CL25, and the SL25 is a little bit more robust. The tubeless interface on both is the same.
> 
> As to lacing, I've been giving SL25s absolutely improbable beatings the last few weeks in tubeless cx tire testing. Just absolutely abusing them in stupid ways, and they haven't put a foot wrong. I certainly respect robt57's experience with regard to front lacing, but at my weight (call it 160) I've got just heaps of confidence in 24 front lacing for road and cx. But far be it from me to talk someone into a lower spoke count.
> 
> We're on Maxxis and Hutchinson tires, our other tester is a little lighter than me, we both run 22f/25r for pressure. I'm ill-inclined to speak in absolutes like "you CAN'T burp them," but I sure haven't been able to, nor has our other tester, who is a much better and more aggressive cx rider than me. We'll start using some Vittorias and maybe some WTBs soon. Thus far, we've eliminated Clement, Challenge, Schwalbe, Kenda, and Michelin as tubeless options. We're incredibly impressed with how well the Maxxis and Hutchinson tires work.


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## November Dave (Dec 7, 2011)

I think the Schwalbe we tried were Rocket Rons. No tubeless designation on them at all. They were loose like wizard's sleeve. For tape we use TESA 4289. If it's not the same exact thing as what others brand, it's indistinguishably different from them. Two wraps. 

We've built A LOT of wheels with aluminum nipples, and they work great as long as your lengths are near perfect and everything is properly prepped with grease or something playing that role. Very recently, we've started using brass nipples simply because they thread better. We were getting somewhat chronic "stiction" with aluminum. Brass are more tolerant.


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## robt57 (Jul 23, 2011)

I have no issues with AL nips, as long as 7075 forged & machined.

Although I sometimes use brass on the working spokes mixed with the AL nips FWIW.

For example the XTR SL25 wheels are drive side rear and disc side fr&rear leading brass and Sapim Race, and the rest of the spokes are AL Nips and Sapim Lasers.



Wizard's Sleeve, LOL


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## twiggy (Mar 23, 2004)

One decision making delay to another.....

Finally decided on Pacenti SL25s, Sapim Lazer Spokes and Sapim Aluminum nipples with a 24/28 build.... then my wheelbuilder told me he refuses to use Lazers to make disc wheels (quoting Sapim's warning against this) and also refuses to make disc wheels w/24 spokes.... Dangit! Back the drawing board!


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## robt57 (Jul 23, 2011)

twiggy said:


> One decision making delay to another.....
> 
> Finally decided on Pacenti SL25s, Sapim Lazer Spokes and Sapim Aluminum nipples with a 24/28 build.... then my wheelbuilder told me he refuses to use Lazers to make disc wheels (quoting Sapim's warning against this) and also refuses to make disc wheels w/24 spokes.... Dangit! Back the drawing board!


I agree with him. Let's guess he knows more about it than you do...

*Ask him to use the D-Lite spokes

As I said, I used Sapim Race & Brass for the loading spokes and Lasers/AL nips for the lazy spokes in my SL25 32 spoke disc build. And this is for me to see if my estimations are correct as to longevity and need of beef, and where in a wheel that beef need to be.


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## November Dave (Dec 7, 2011)

Just use D-Lites, I agree. 

For what it's worth, DT Swiss endorses their Revolutions (equivalent to Laser) as excellent spokes for XC use. Our experience with Lasers in discs has been perfect. I don't think I've ever ridden a disc wheel that didn't have Lasers in it, but you have to respect your builder's conditions.


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## ergott (Feb 26, 2006)

robt57 said:


> As I said, I used Sapim Race & Brass for the *loading *spokes and Lasers/AL nips for the *lazy *spokes in my SL25 32 spoke disc build. And this is for me to see if my estimations are correct as to longevity and need of beef, and where in a wheel that beef need to be.


You've mentioned this a few times. A wheel is supported by all the spokes and when you apply torque all spokes continue to support the rim. You should check out Jobst's book. His FEM is excellent.


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## robt57 (Jul 23, 2011)

ergott said:


> You've mentioned this a few times. A wheel is supported by all the spokes and when you apply torque all spokes continue to support the rim. You should check out Jobst's book. His FEM is excellent.


Beyond supporting the rim, braking forces on disc wheels and drive forces on all rears regarding torsional load is to what I was referring and targeting for the build. Applied torque stretches some while letting out stretch on other same time, no?

So, are not the currently stretched spokes and not the less loaded ones supporting more under loads?


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## ergott (Feb 26, 2006)

The tension drops on the "pushing" spokes, but they are still supporting the wheel and therefore still contributing to torque stiffness.


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## robt57 (Jul 23, 2011)

ergott said:


> The tension drops on the "pushing" spokes, but they are still supporting the wheel and therefore still contributing to torque stiffness.


OK, to a lesser degree or no as far as the point??


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## ergott (Feb 26, 2006)

Point is that since they are all contributing to resisting torque why not keep them all heavier gauge on the flange that is closer to the centerline? It's only about 10g difference.

Also, alloy nipple are more than up to the task in a wheel. Brass makes sense for corrosion resistance, but won't make the wheel any stronger.


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## robt57 (Jul 23, 2011)

ergott said:


> Point is that since they are all contributing to resisting torque why not keep them all heavier gauge on the flange that is closer to the centerline? It's only about 10g difference.
> 
> Also, alloy nipple are more than up to the task in a wheel. Brass makes sense for corrosion resistance, but won't make the wheel any stronger.


I do put the heavier ga. 'working' spokes all heads in. 

I have a big bag of the brass nips. So using some up may be part of it for me.

I don't do this to save spoke weight, but rather to have the 'lazy' spokes under more tension to start with and keep them from coming 'as' slack as they might otherwise when being 'pushed' to use one term [I think you used]. But if that weight is not needed in my minds eye for those spoke to do there job, why put it there. 

Thanks for the civil interchange...


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## Heuston (May 23, 2013)

I build up a Pacenti SL25 with 32 spokes front and rear using Lasers and alloy nipples (disc brakes) No issues after 2,000kms.


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## twiggy (Mar 23, 2004)

It occurs to me now that I never updated my thread!

Ended up having a few problems along the way with my build.
For one, Sapim USA sat on the order of D-Light spokes for several weeks.... spokes that we ordered in August still hadn't shown up at the beginning of October!... A call to Sapim revealed that they had somehow missed it in the shipping que. The spokes arrived at my builder's shop just 5 days before my biggest CX race of the year...Canadian Nationals. Unfortunately my builder screwed up as well, forgetting to order the end caps I needed to run my front Thru-axle.

Regardless, he managed to build up my rear wheel in a day.... its pretty sweet. SL25 Rim, Red Sapim Alloy nipples, 28 Black D-Light Spokes....as crazy as it sounds, the rear wheel alone is 0.9lb lighter than the rear wheel that it replaced (a stock Giant wheel). I've been very happy with it so far. I tried setting it up tubeless for my last weekend of racing (a week after CX Nationals) and had a Tubeless Schwalbe tire (Super Swan) roll off the rim mid-race; but I'm attributing that to likely user-error....I didn't really clean the rim well before trying to seat the tire, and I'm not even 100% sure I had properly 'snapped' the bead into place before dropping to a proper CX Pressure....I was setting it up in a rush the night before the race.....never again.

I'm looking forward to taking my time and attempting a proper tubeless setup next season.

In the meantime, the front hub end caps have just arrived, so I should have my new front wheel in the next day or so!


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## robt57 (Jul 23, 2011)

setting it up in a rush the night before the race.....never again....


You ought to know better, and if not you sure do now.


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## twiggy (Mar 23, 2004)

I thought this was a race that I didn't care about (I told myself that after nationals, the last two of the year didn't matter) - but try 'not caring' when you're walking off of the course with your bike on your shoulder after being in the lead group of 3 25 minutes in and with a sizable gap on 4th....  I've realized I'm incapable of 'not caring' when I line up at any race.

Lesson learned  .... lots of time to vet tubeless setups between now and next September, luckily


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## robt57 (Jul 23, 2011)

twiggy said:


> Lesson learned  .... lots of time to vet tubeless setups between now and next September, luckily


We can not imagine knowledge we do not possess. You possess more now...

Live and learn pretty much...


You could have just as easily flatted any setup and had the same result, you probably realize,


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## November Dave (Dec 7, 2011)

Let me give you a gigantic head start with that. 

The Hutchinson Toro front/Black Mamba rear has become my particular favorite through a fairly dry season to date. For the few wet races (haven't really had any true mud fests this year), the Maxxis Mud Wrestlers have been great. 

A good tubeless setup *will not burp*, and you already own the most critical piece of the equation.


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## twiggy (Mar 23, 2004)

November Dave said:


> Let me give you a gigantic head start with that.
> 
> The Hutchinson Toro front/Black Mamba rear has become my particular favorite through a fairly dry season to date. For the few wet races (haven't really had any true mud fests this year), the Maxxis Mud Wrestlers have been great.
> 
> A good tubeless setup *will not burp*, and you already own the most critical piece of the equation.


Thanks Dave!! I already had your article bookmarked as my go-to reference. Interesting that you should stress the fact that a good tubeless setup won't burp - I had that exact discussion with two teammates at the race where I rolled my tire....I argued that a non-burping tubeless setup was possible, but that I had just paid the price for not setting it up properly..... 

Although they both ran, and endorsed tubeless setups, and both were familiar with your blog; they both insisted that 'some' small burps were all but unavoidable. They showed me that even their cherished setups (in one case Vittoria TNT tires on American Classic Tubeless Rims, and in the other Specialized TBliss tires on supposedly tubeless Alex rims, stock on a Norco) showed signs of small burps at the end of that race, and finished the event a few PSI lower then they had started at.

I argued that I was sure a 'burpless' system should be possible with the right tire/rim combo (I was basing my comments more on the results of your testing than on my own experience).... glad to hear that you believe the same!

I believe I may try the exact Toro/Black Mamba combo you suggest for next season....although I admit I'm a bit worried about the longevity of the Black Mamba.

I'm really curious to see how the Clement Tubeless-ready MXP is when it comes out.... I suppose it'll require a decent amount of testing to determine whether it can compete with the tires that you're suggesting already.


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## November Dave (Dec 7, 2011)

I think the whole planet is excited for the Clement tubeless tires to come out. 

A burpless system is definitely possible, the enormous caveat is that it's a recipe. Even among brands, things are specific; tires that work on Stan's Grails don't always work on Alpha 340s. The stock setups that are coming on bikes are a complete tossup. Get a Trek with the good carbon Bontrager wheels and a set of their tubeless tires and I'm pretty certain they're going to work well, but I've seen first hand stock rims that say "tubeless" in big letters right on them and they're hopeless. All that does is confuse the market and add weight to the claims that it's not ready for primetime or whatever. 

I don't think I'll ever comment on the topic without saying 1) that in order to have success, you have to follow a known recipe - throwing whatever tire on whatever rim is a recipe for disappointment and 2) despite a lot of data points of successful use at top level racing, the BEST performing setups are and probably will always be tubulars. But tubulars come with tradeoffs, too. Everything does. 

My Black Mamba gets used all the time, it's fast and gives enough grip and I love it and it's hard to convince myself not to use it even when it's probably not the right tire. But I never use it on the road. Seriously, it might have 10 pavement miles on it, 6 of which probably occurred in races. There's some wear on it but the tread's still intact.


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