Pacenti PL23 longevity?

[Chris Cullum]

I have an original model PL23 32h on my front dynohub with about maybe 5000km and it's already worn off the wear indicator. I don't feel the original model of this rim is up being used as high dish rear rim based on what I have seen from rims cracking. However I think it's pretty good for a lightweight symmetrical front wheel.

5000km seems really low to me to think that it is already time for replacement. I ride a lot in the rain but get closer to 20,000km on Mavic Open Pro on the front wheel of my 700C rando bike. I have 2 other unused PL23 rims (1 in 650B 1 in 700C) that I bought when they first came out (before they got closed out at half price and replaced with the slightly beefier gen 2 PL23). Is that low mileage normal? Is the wear indicator very conservative and I can keep on riding it for more kms? Any one have any experience with them. I'm talking about sidewall wear not cracking. My rim seems OK in regards to cracking but it is front wheel and is laced with 32 DT Revolution spokes.

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Chris Cullum
Vancouver, BC

[Michael Mann]

I'm in the same boat with the same rims. Past the wear indicator and my gut tells me the sides are pretty thin. Not taking chances and my rebuild will be something beefier from Velocity. Fastest wearing rim ever.

Mike

Sent from my iPhone

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[Theo Elliot Roffe]

Hey Chris,

I've replaced two PL23 32h rims, both used for my front wheel with none of the cracking issues associated with higher tension on these rims. 

The first one I replaced after a fairly short time and distance. It had a lot of use during rainy weather and the wear indicator was gone pretty quickly.  I don't have notes for the distance, but mostly used it commuting (~25km/day) for about 6 months before I got worried enough to replace it. We took out a cross section after the rim swap and the braking surfaces had worn down, but didn't look frighteningly thin. The second rim got a lot more use - maybe I was less worried about the wear after that first cross section - and was used through most of 2013 and all of 2014, for a total of over 16,000km (I don't track commuting, so that distance is based on randonneuring - brevets and permanents).

By early January 2015, I was starting to worry about the rim - the surface was concave to the point that it easily fit my fingertip.  I swapped to a new model PL23 and cut up the old rim to get a look at the wear... What I saw was pretty sketchy.. as thin as a knifeblade. I'm pretty surprised that it never cracked, actually, but I guess running 42mm tires at ~30psi helped.

That's not a very scientific evaluation, but my sense is that the wear indicator is very conservative. Still, these rims don't last forever...

-Theo Roffe

Portland, OR

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[Chris Cullum]

Thanks Theo, that makes sense. While the wear indicator is gone the sidewalls don't look particularly concave. It's probably less than 5000km at this point. Sounds like your second rim was pushing the envelope, maybe somewhere in between is what to aim for. They do seem especially fast wearing. The rims are wearing out much faster than the tires. Maybe the alloy is softer than some other rims? It's too bad because they are nice rims and Hetres actually seat fine on them. I've still got a couple of unused rims so I'm fairly committed. Also the erd is larger than most modern rims so any rim swapping would require a total rebuild including spokes.

[Harald Kliems]

I have a new pair waiting to be built up. I'm currently in the middle of a move, but once that's done I'll make sure to measure the sidewall thickness with my dental calipers on the new rim. 

 Harald.

[Chris Cullum]

On Feb 5, 2015 5:13 PM, "Harald Kliems" <kli...@gmail.com> wrote:
>
> I have a new pair waiting to be built up. I'm currently in the middle of a move, but once that's done I'll make sure to measure the sidewall thickness with my dental calipers on the new rim. 
>  Harald.
>

Harald, you say pair so I assume front and rear? Others may disagree but I think the PL23 is pushing it for a highly dished rear wheel. I've seen a few fail on the driveside spoke holes. Maybe the gen 2 version is strong enough?

>
> On Thursday, February 5, 2015 at 2:47:17 PM UTC-6, Chris Cullum wrote:
>>
>> I have an original model PL23 32h on my front dynohub with about maybe 5000km and it's already worn off the wear indicator. I don't feel the original model of this rim is up being used as high dish rear rim based on what I have seen from rims cracking. However I think it's pretty good for a lightweight symmetrical front wheel.
>>
>> 5000km seems really low to me to think that it is already time for replacement. I ride a lot in the rain but get closer to 20,000km on Mavic Open Pro on the front wheel of my 700C rando bike. I have 2 other unused PL23 rims (1 in 650B 1 in 700C) that I bought when they first came out (before they got closed out at half price and replaced with the slightly beefier gen 2 PL23). Is that low mileage normal? Is the wear indicator very conservative and I can keep on riding it for more kms? Any one have any experience with them. I'm talking about sidewall wear not cracking. My rim seems OK in regards to cracking but it is front wheel and is laced with 32 DT Revolution spokes.
>>
>> --
>> Chris Cullum
>> Vancouver, BC
>

[Steve Chan]

  Sounds like a good rim for an NFE disc front wheel...

   Those rims were always pretty obviously a weight weenie rim, but 5k sounds way too short of a lifespan. Do you do a lot of steep descents?

[Chris Cullum]

On Feb 5, 2015 8:00 PM, "Steve Chan" <sych...@gmail.com> wrote:
>
>
>   Sounds like a good rim for an NFE disc front wheel...
>
>    Those rims were always pretty obviously a weight weenie rim, but 5k sounds way too short of a lifespan. Do you do a lot of steep descents?

I normally do a lot of steep descents but that hasn't been the case here. It's been pretty much moderately hilly commuting, all on road. I've even started taking to wiping the rims down occasionally and making sure there was no grit embedded in the brake pads (Koolstop salmon's) in an effort to reduce the wear.

[Michael Mann]

I'll echo Chris's comments. My miles are wet but mostly flat, and I'm pretty anal about wiping down wet rims and keeping them and pads (also Kool Stop salmon) clean. 15 months and they are worn out. I tend to think they are just soft rims. Probably replacing with Aeroheat rims.

[Kirk Pacenti]

Dear B'ers,

I won't address everyone's concerns individually in this post, but I will reiterate that I stand behind my products 100%.

If anyone is dissatisfied with the original PL23 rim, or feel it has not lived up to your expectations*, I am happy to offer the new PL23 at a 40% discount, for all rims that are less than 24 months old.

* I will assume that no one really expected a 400g rim to have the same service life as a 500g rim...

Call anytime and we'll get you taken care of.

Cheers,
KP

[Jan Heine]

At 5:07 AM -0800 2/6/15, Kirk Pacenti wrote:

* I will assume that no one really expected a 400g rim to have the same service life as a 500g rim...

I think Kirk makes a good point here. Many users are tempted by lightweight rims or tires, without asking where the material is removed. On a well-designed rim or tire, the only "extra" material is on the wear surface. You can remove material there pretty easily to make it lighter... but that will dramatically reduce the service life.

For example, if we assume that a rim sidewall should be 0.8 mm thick to be safe, then a rim with 0.81 mm walls will be lightest, but it will wear out the first time you brake. A rim with 1.2 mm sidewalls will have an infinitely longer lifespan, yet weigh only 41 g more. And a rim with 1.6 mm walls will last twice as long as the one with 1.2 mm walls, but weigh only another 41 g more. Still, you have gone from a 380 g rim or so (with no service life) to a 462 g rim...

Whether you prefer the 421 g rim or the 462 g rim depends. If you live in a flat place and ride only in the dry, the 421 g rim may give you many years of service. And if you use that wheelset only for special events, why not get the lightest possible? For example, in Paris-Brest-Paris, I'll probably brake eight times. (However, the resulting speed gains from slightly lighter rims and tires also are small.)

Of course, there also are poorly designed parts that have extra material where it's not needed. Some tires have as much tread on the shoulders as in the center. The shoulders don't wear (we don't spend that much time leaning hard into corners!), so the material there is unnecessary.

It's also easy to get carried away, and keep adding material to the wear surfaces. Too much material in one place causes stress risers, so then you have to add material elsewhere, and you get into a vicious cycle that makes your components heavier and heavier.

When I design components, I remove the unnecessary material, but keep enough on the wear surfaces to result in what I consider more than acceptable service life. For special events, I sometimes run well-used components, which have some of the extra material removed.

For other components, most weight gains come from smart design. Understanding the stresses and being creative about solving the associated issues goes a long way toward reducing weight. For example, centerpull brakes are much lighter than sidepulls and dual pivots, because they isolate the twisting loads of the rim dragging the brake pads along to a short section between the pad and pivot. The upper arms only have to deal with the planar loads of the brake cable pulling upward, so they can be very thin.

It's just that for rims and tires, once you are using a lightweight material (aluminum for rims; high-end casings for tires), there isn't much you can do to remove weight...

Jan Heine

Compass Bicycles Ltd.

http://www.compasscycle.com

Follow our blog at http://janheine.wordpress.com/

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[Harald Kliems]

I take back everything I said and claim the opposite. I of course have the _S_L-23 rims. Sorry about that.

Harald.

[blueride2]

I love lightweight rims and am willing to sacrifice some longevity to use them. I have a set of the original PL23 rims with maybe 2K miles, and haven't had any problems. The SL23 rims are also a blast to ride. Coupled with lightweight, wide tires, these rims make a fast wheelset that can really transform a bike. I know, I know, the engine makes the difference, but a little help never hurts.

Richard

[Michael Mann]

In a perfect world, I'd have wheels I could swap out. I like the performance of the Pl23 wheelset, and if I could have just used them as  dry weather "event" wheels while switching out to something more robust for winter commuting, I would do so. But I'm not there yet. And I built mine up with a SON 28 front/White T11 rear - so it was a significant outlay on my part. 

I'm going to probably rebuild these hubs onto more robust rims like the Aeroheats. Unfortunately that will mean new spokes too.

But a lightweight set of wheels with a non-generator front hub and the White rear built on PL23s would be a sweet event wheelset.

Anyone stockpiled any of the PL23s in 32 hole they want to unload? I should have pulled the trigger when they were cheap on eBay.

Mike

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Michael Mann
http://baiku-velomann.blogspot.com/

[Fred Blasdel]

On Thu, Feb 5, 2015 at 8:00 PM, Steve Chan <sych...@gmail.com> wrote:

  Sounds like a good rim for an NFE disc front wheel...

This is a poor idea! Disc braking forces are concentrated at the spoke holes, and the original version of these suffered cracks there when stressed.

It's pretty silly in general to use a traditional rim with discs, since the design can be optimized so much further. The WTB Frequency and KOM rims are the best example of that on the market.

[Nick Payne]

You can calculate the additional spoke tension caused by braking. Maximum possible braking force on a bicycle is around 0.6G before you go over the handlebars - the exact figure depends on where your centre of mass is, whether you are ascending (which will increase the max because your centre of mass is further behind the front wheel), or descending (the reverse), whether additional weight is in rear panniers, handlebar bag, etc. The 0.6G is the approximate figure for a rider seated on the saddle on an unloaded bicycle on a flat road.

Lets make a few assumptions:

1. The front brake is powerful enough to apply this 0.6G, so that all the braking force is in the front wheel.

2. Weight of bike + rider is 100kg.

3. Wheel built as 32 spoke x3 - I measured the 32 spoke x3 front disk brake wheel in one of our tandems, and the spokes are at an effective radius of 30mm - i.e. if you extend the line of the spoke and take the length of the perpendicular to the axle centre, that measures 30mm.

4. Hetre tyre. This has an outside radius of ~335mm.

5. The hub shell is torsionally rigid enough that the braking force is shared equally on both sides.

With these assumptions, we first calculate the braking force of the tyre against the road to achieve a 0.6G deceleration: f=mass*acceleration=0.6x9.8x100=588 Newtons (G is 9.8 metres per second per second)

This force is applied at a radius of 335mm, therefore the spokes at their 30mm radius at the hub are operating at a mechanical disadvantage of 335/30=11.17 times, and this force is being carried by 16 of the spokes (the other 16 spokes exit the hub in the other direction and don't contribute to the braking effect, in fact they will lose tension while braking).

Therefore additional tension on each of those 16 spokes at maximum braking is 588*11.17/16=410N == 42Kgf (one Kgf is by definition 9.8N).

So if the wheel is built with the spokes initially tensioned to 100Kgf, in a panic stop where you are at the point of going over the handlebars, the tension of half the spokes in the front wheel is increased by about 40%.

It's simple enough to do the calculation for different weights, spoke counts, and hub flange diameters - just substitute the different values in the formulas.

Nick

[Kirk Pacenti]

I re-read my previous post an realized that it could use some clarification.

If anyone has a set of PL23 rims that are less than 24months old, and they are dissatisfied with them, you can return them and purchase a new PL23 rims at a 40% discount.

For more info feel free to call me directly: 423.531.6136

Best regards,

KP

[Max]

Resurrecting this old thread in the hope that someone has attempted to use the new Brevet rim as a drop-in / re-rim replacement for worn PL23 in the 650b designation. Maybe Kirk can chime in if this works? How was your experience? 

- Max "573 mm vs. 574 mm, I suppose I could always use washers, but..." in A2 

[Bob Ehrenbeck]

I've done this, replaced a set of original PL23s with Brevets. The rims built up nicely with the exisitng spokes. 

https://www.instagram.com/p/Bf_25AflAu6/?utm_source=ig_web_copy_link

Bob E

Cranford, NJ

[satanas]

Thanks Bob! I have a set of as-yet-uncracked PL23 wheels and Brevet rims to replace them but might rebuild the wheels sooner rather than later. The PL23s really are buggers to get tyres on and off.

Later,
Stephen

[Bob Ehrenbeck]

You're welcome, Stephen!

Yes, they are a bugger -- the only reason I swapped them out for Brevets was because of how difficult it was for me to mount/remove tires. I haven't experienced cracks at the spoke holes either, but then I'm no heavyweight, and I didn't overtension the spokes.

But in case you do keep those PL23s on for a while, you might be interested in this (it's not my video, but those are my actual former rims):

https://www.youtube.com/watch?v=nNiJUuSNOcI

Bob E

Cranford, New Jersey

[Stephen Poole]

That guy in the video must have much stronger hands than me - not difficult as I've sprained both thumbs more than once. Despite decades of bike shop experience, Stans tape, and using the VAR bead jack levers I've found those rims way more difficult to get tyres on and off. Also up there are anything Campagnolo, Shimano C24 TL, old Wolber aero rims, Mistral 17"/369 rims with no wells(!), etc. On the other hand, most Mavic and Velocity rims are painless, as are Stans Crest MK3.

Can anyone who's used the HED Belgium+ rims please comment on the relative difficulty of mounting tyres on those?

Later,

Stephen (who has several wheels to build)