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Building tubeless ~40mm wheels

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Building tubeless ~40mm wheels

Old 05-03-23, 06:32 AM
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somebikeguy 
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Building tubeless rim brake wheels for ~40mm tires

Hi all

I just built my first set of wheels for my vintage road bike using Pacenti Brevets / Velo Orange hubs 32h/32h. Very rewarding experience and I'm a total tubeless convert. Running 30mm Contis on that bike.

I have a cool Cantilever brake SwissCross frame incoming and am looking to build a set of wheels for it as well. I want to keep things 90's looking (even tho the frame is from the teens) so I'm looking for a polished rimbrake rim that can handle 40mm tires. Pacenti offers the Forza Classico which seems to fit the bill.
Front is symmetric, Rear is asymmetric. After building my first rear I definitely see the value in asymmetric!
https://pacenticycledesign.com/colle...al-700c-silver
https://pacenticycledesign.com/colle...-700c-silver-1

I am trying to decide on spoke count. I am on the light side (~135lbs dressed) and the SwissCross has no bag mounts / I do not plan to tour. For that reason I'm considering either 32r/28f or 28r/24f. I am not a maniacal gram-shaver but I do like trying new things and my understanding is that a wide and deep rim like the Forza is inherently stronger meaning I could likely build a strong and durable wheelset with fewer spokes. FWIW when I look at prebuilt alum wheelsets intended for cross/gravel I overwhelmingly see 28h and below, often same spoke count front and rear.

My plan was to use Bitex hubs, which Pacenti themselves use in their wheelsets.
https://www.bikehubstore.com/RAR12-p/rar12.htm
https://www.bikehubstore.com/SL85W-p/raf12.htm

I'd also looked at the Velocity A23, but its narrower internal dim seemed a bit less suited to the 40mm tires.
https://www.velocityusa.com/product/rims/a23-622

Hunt has an interesting silver wheel coming soon but they seem to be on the ragged edge of the low spoke revolution offering only 24r/20f.
https://us.huntbikewheels.com/produc...-aero-wide-rim

Open to other ideas, and tubeless 38-40mm tire recommendations!

Last edited by somebikeguy; 05-03-23 at 08:54 AM.
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Old 05-03-23, 01:00 PM
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https://www.retro-gression.com/produ...31865562267709
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Old 05-03-23, 07:04 PM
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24/28 will be fine for you. Maybe things have changed but the A23 is a pretty mediocre rim. Newer Velocity rims are better, if the Quill is representative. My experience with Pacenti has been decent though I did crack a brake track on one of their rims a few years ago. I’m close to your weight, perhaps 5 lbs under on a good day.

This is a bit off-topic, but a bit of unsolicited advice as a former Swiss Cross owner: I strongly advise using a mini-V front brake and not a traditional cantilever. I used a TRP CX 8.4, I hear the Paul Mini-Moto is excellent as well. The fork on this bike has a lot of fore-aft flex and so brake chatter with a standard cantilever brake can be very severe. In fact I found it to be borderline unridable without the mini-V. Probably the biggest flaw in this generation of Swiss Cross.
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Old 05-03-23, 07:09 PM
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Appreciate that feedback. I've been warned on the chatter. I'm not sure I understand why the mini V as opposed to a canitlever makes it better, can you help me understand that?
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Old 05-04-23, 07:02 AM
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Originally Posted by somebikeguy
Appreciate that feedback. I've been warned on the chatter. I'm not sure I understand why the mini V as opposed to a canitlever makes it better, can you help me understand that?
The cable is anchored at the top of the headtube and at the brake pivots. When you brake, it acts like a bow string, with the fork steerer and legs between those two points acting as the back of the bow. That is, they bend and that builds up an increasing amount of strain that has to be released. Itís released by the brake pads abruptly slipping, the fork springs back, then the pads grab again and the cycle re-starts. Itís that rapid release and grab that manifests as brake chatter. With a mini-V brake, you eliminate the long section of steer tube and fork legs that flexes between upper headset and brake pivots, so this (mostly) stops the brake chatter. Using a fork crown cable stop is also a common method for solving brake chatter for the same reason (the length of fork that can bend is much shorter and overall stiffer), but the Swiss Cross doesnít have a drilled fork crown. So a mini-V is the only real option that also preserves a reasonable amount of braking power.

Hereís Zinn on brake chatter on cyclocross bikes: https://www.velonews.com/gear/techni...turn-to-cross/
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Old 05-04-23, 07:06 AM
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Thanks - again appreciated. I only have experience with V-brakes (full size) on my Ellsworth Truth, have never owned a Canti bike so forgive if dumb q: I presume that this routing at the stem doesn't alleviate the issue you are describing?

"being forced" into using a very trick looking Paul Minimoto is not the end of the world...

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Old 05-04-23, 08:01 AM
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No, that routing is a major cause of the issue.
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Old 05-04-23, 03:26 PM
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Got it, keeping eyes peeled for a set of Paul Mini Motos. Silver or Blue would look cool I think.

Ordered Pacenti Forza Classico wheels, Bitex Hubs and hope to have this project rolling in a few weeks!
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Old 05-09-23, 10:46 AM
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Have my very nice Pacenti wheels laced up, will stop by a friend's place to true them this weekend. I believe I'll have a maximum of 40mm clearance at the rear but more in the front (frame arrives tomorrow). I was thinking of buying one Panaracer Gravelking SS+ 43 to use at the front, which I could test-fit to the rear to see if there's any way it'd fit. If not, I'd have to step down to 38 at the rear since Gravelking doesn't have anything in between. If anyone has direct experience to share of actual width of current production Gravelkings on 20mm internal width rims, please share!

The backup plan is to use Terra Speed 40's all around. My Conti GP5000 30's measure dead-on 30mm when installed on my 19mm internal rims, so I'd expect to be able to fit those front and rear no problem.


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