Replacing rims

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si_c

Guru
Location
Wirral
With respect, @si_c , have you read the OP's two posts? I think it's reasonable to assume he is "aware of a few things" already.

Fair point :blush::laugh:


Nice rims those, very pretty, albeit a bit spendy.
 

Spoked Wheels

Legendary Member
Location
Bournemouth
I need to replace some Pacenti SL25 disc rims -

View attachment 394013

My wheels have a 32 spoke count front and rear.

Is it possible to change the rims without buying all new spokes as well?

If so, can people recommend other rims that would work?

The SL25s are discontinued so I can't seem to find them anywhere in a 32 hole drilling (though if anyone else knows where to source some please do shout up). The Pacenti replacement rim is the Forza but I'm not sure if these would work as they are asymmetrical so presumably spoke lengths would need to be slightly different?


View attachment 394014

Cheers,

Bill


Sorry I just saw this.

The SL25's ERD is 590mm and the forza 591mm. You must have worked out the spoke length already so I assume you know what you are doing. I suggest you do that again but this time with ERD = 591mm and I'd bet you can use the same spokes.
BTW, you can use two front rims if you don't want to use asymmetrical but as a rule of thum you need spokes 1mm longer (RIGHT SIDE) when using asymmetrical rims, having said that I have used spokes for symmetrical with asymmetrical rims without a problem.

I hope that helps.

BTW, somebody at the beginning of this thread said Why bother with new rims? Lots of wheels can be re-rimed 3 times with the same spokes and hubs so for some people it's an excellent opportunity to save money and keep using the wheels they have come to love and trust.
 

Ajax Bay

Guru
Location
East Devon
maybe PC you could sort
PL25 not on there but here's a sort (all 622 ETRTO) either side of 591mm (last figure (normally zero) is 'offset of spoke bed'):
hed 592 0
Hed Ardennes 592 2.5
Hed Belgium. Could not find definitive source on offset spoke bed. 592 0
HED C2 Belgian Aluminum version 592 0
hed c2 campy 592 0
HED C2 Tubular 592 0
Matrix ISO 3 592 0
NOTUBES ZTR ALPHA 340 592 0
Remerx Master Disc RDX 7320 622X18 592 17
Stan's Alpha 400 592 0
Sun Venus (medium deep aero) 592 0
Accent roadrunner OSB probably none 591 0
H+Son Archtype 591 0
Halo Aerorage OBB 591 0
hson 591 0
Kaka Felge 3 591 0
Mavic CXP30 36h 591 0
Stans Alpha 340 591 0
Velocity Fusion 591 0
Xtreme ATB 28" T-XP 19 591 0
Alex AT-490 590 0
alex r380 New rim 590 0
Ambrosio FCS 28 590 0
Exal XR3 Taken from manufacturers website 590 0
Halo Aerowarrior 590 0
Halo Freedom 590 0
Mach1/Tiagra-FH4600/DT Swiss Mach1/Tiagra-FH4600/DT Swiss 590 0
Mavic cxp30 (16mm) 590 0
Stan's The Grail clincher 590 0
woodenrim 590 10
Spank Subrosa 29" 589 0
Ambrosio Camel 588 0
Pacenti SL23 from fairwheelbikes.com 588 0
Rodi Airline Evo 588 0
SCHURMANN 588 0
 
OP
OP
B

BillyS79

Active Member
First of all, thanks so much to everyone for the comprehensive help, guidance and suggestions - it's massively appreciated.

why do you need to replace rims on a disc-braked bike
Can I ask why the rims are no good ?
I’m also interested in why you need to replace your existing SL25 rims as I’ve found them to be bullet proof?
I made the schoolboy error of originally ordering my rims from Planet X - at the time they were showing SL25s in stock in 24/28/32 hole drillings. I ordered 2x 32h. They sent me 2x28h. So I sent them back with an explanation and swiftly received 2x 32h rims, but this time a different type of rim altogether...! So I rang them and asked what was going on and they admitted they didn't have any 32h SL25s in stock and shouldn't have been taking orders for them. I'd already calculated spoke lengths and ordered spokes by then...I won't make that mistake again!

The Forza states it has a machined brake surface so are these actually a replacement for the disc brake specific SL25?
Yes. Because they come in 2 versions - disc and rim -
https://www.sigmasports.com/item/Pacenti/Forza-Disc-OC-Rim/F14Q
https://www.sigmasports.com/item/Pacenti/Forza-Road-Rear-Open-Clincher-Rim/FRUK

just buy 2 x front 'normal' rims
Good idea - I'd not thought of that! Though bizarrely when I try to place an order at any of the likely online retailers they don't seem to differentiate between front and rear, they just list the rim and you select how many you want. Hmmm.

If not, the H Plus Son Hydra Disc specific rims have an identical ERD of 589 which would mean you could definitely use your existing spokes. Their internal width is also identical at 20mm. I haven’t built with the Hydra rim, but have previously built a couple of wheels with the H Plus Son Archetype rims and found the build quality of said rims to be excellent.

Thank you for doing that research for me and suggesting those. I get very little time online and wasn't sure how reliable these ERD measurements were as a guide. I have heard great things about H+Son rims and these are good looking, and tubeless ready.
It hurts to order these when the SL25s are going for £19.99 each, but I think that's what I'll do.
 
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Thank you for doing that research for me and suggesting those. I get very little time online and wasn't sure how reliable these ERD measurements were as a guide. I have heard great things about H+Son rims and these are good looking, and tubeless ready.
It hurts to order these when the SL25s are going for £19.99 each!

Yeah. That's a great price, but I think it's only for the 24h version. No way I'd build wheels with only 24 spokes as I'm 15 stone.

If you're a lot lighter than me though you may be ok.

Graham
 
OP
OP
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BillyS79

Active Member
The SL25's ERD is 590mm and the forza 591mm. You must have worked out the spoke length already so I assume you know what you are doing. I suggest you do that again but this time with ERD = 591mm and I'd bet you can use the same spokes.
You are right, assuming I don't use the asymmetric rear. Thanks.

PL25 not on there but here's a sort (all 622 ETRTO) either side of 591mm
Thanks for finding and listing that, just what I was after when I made the OP, without realising such a thing existed!

@Spoked Wheels @Ajax Bay - I'm going to go with the Hyrdas, but just as an aside, in your experience is there a general rule of thumb for discrepancies with ERD when exchanging one rim for another? i.e 1mm either side perhaps? But presumably best to find a new rim with an identical ERD of course.
 

si_c

Guru
Location
Wirral
You are right, assuming I don't use the asymmetric rear. Thanks.


Thanks for finding and listing that, just what I was after when I made the OP, without realising such a thing existed!

@Spoked Wheels @Ajax Bay - I'm going to go with the Hyrdas, but just as an aside, in your experience is there a general rule of thumb for discrepancies with ERD when exchanging one rim for another? i.e 1mm either side perhaps? But presumably best to find a new rim with an identical ERD of course.

If it's a small difference (say around 1-2mm) then it is unlikely that there will be problems, if the ERD is smaller, then you can run into problems with the spoke being too long and being raised over the top of the spoke nipple. In that case you probably run into problems trying to tension the spoke properly, so you'll need to cut the spokes and re-thread them (if you have the tools).

If the spoke is too short by a mm or two, you can get longer spoke nipples (say 15mm instead of 12mm) which will solve the problem, although only to a limit.
 
OP
OP
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BillyS79

Active Member
No way I'd build wheels with only 24 spokes as I'm 15 stone.

If you're a lot lighter than me though you may be ok.

Going off topic here....

The SL25s look a real bargain at £20 (assuming PX actually have them in stock, unlike my 32holers!) but I was surprised to see disc rims available in such a low spoke count. I weigh just 9.5 stone and am pretty 'light on my feet' as a rider, and the wheels I am building are purely for road riding, so surely if anyone's circumstances could justify 24 spokes it'd be mine?

But my concern with such a low count would be the forces travelling through the spokes when braking on steep descents - would 24 spokes in a 2 cross pattern be up to the job of sustaining these forces travelling from hub to rim with a disc brake?

@Ajax Bay @Spoked Wheels @si_c - what are your thoughts on this?

As they sell them in 24h I guess someone cleverer than me must have done the maths and the testing and decided it's all fine. And I see Fulcrum even do 21 spoke disc wheels, and Giant do a disc bike with 20 spoke wheels!!

it's a moot point as I'm going to go with 32h Hyrdas (the wheels will sometimes be used for long-distance rides and bike-packing, so although 32 front and rear might seem excessive I'd rather play safe), but I'd be interested to know what people more experienced than me think about such low-spoke counts on disc wheels.
Thanks, Bill.
 

Ajax Bay

Guru
Location
East Devon
I cannot add value based on experience except that my wheels (75kg) are (possibly over-engineered) 32-36 for a road bike used for audax (with the occasional rough track and sometimes with up to 10kg of touring baggage).
I see the CL25s are being sold at £25 (32s) on clearance ends today) but they are ERD 607. Maybe you should not limit yourself just because you've bought 70 spokes of a particular length. You may find that PX are prepared to do a deal (ie rims and right length spokes, ?in exchange for your spokes?), given they screwed you up offering the SL25 in 32 when they actually had none and weren't going to get any more.
 
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Spoked Wheels

Legendary Member
Location
Bournemouth
You are right, assuming I don't use the asymmetric rear. Thanks.


Thanks for finding and listing that, just what I was after when I made the OP, without realising such a thing existed!

@Spoked Wheels @Ajax Bay - I'm going to go with the Hyrdas, but just as an aside, in your experience is there a general rule of thumb for discrepancies with ERD when exchanging one rim for another? i.e 1mm either side perhaps? But presumably best to find a new rim with an identical ERD of course.
1mm it's OK, obviously exact ERD is preferable.
 
I’ve built wheels with SL25

Have you built several wheelsets using those rims? And if so have you mounted any tyres on them? I ask as I'm having some wheels built with SL25 rims currently (with 24 spokes at the front I might add!) and my wheelbuilder suggested 30mm tyres would be ideal. I realize 25mm would be a bit outside Sheldon's recommendations for a rim with that internal width but I have a couple of sets of 25mm tyres I was hoping to get through before buying in anything wider. Just wondered if you'd mounted different width tyres on SL25s and how well different widths fitted and ran? Cheers.

Apologies to the OP for taking this off-topic again!
 
Have you built several wheelsets using those rims? And if so have you mounted any tyres on them? I ask as I'm having some wheels built with SL25 rims currently (with 24 spokes at the front I might add!) and my wheelbuilder suggested 30mm tyres would be ideal. I realize 25mm would be a bit outside Sheldon's recommendations for a rim with that internal width but I have a couple of sets of 25mm tyres I was hoping to get through before buying in anything wider. Just wondered if you'd mounted different width tyres on SL25s and how well different widths fitted and ran? Cheers.

Apologies to the OP for taking this off-topic again!

I’ve built one complete wheelset using SL25s and also an additional front on a Forza with a Son28 dynamo hub. I use these rims all year round on my workhorse/commuter CAADX.

For most of the year I run 28C Michelin Pro4 Endurance tyres and in the winter months 28C Schwalbe M+, both of which which form a nice profile on the rims.

I would guess that 30C should be fine also with no ‘lightbulb’ profile.

I’ve not tried 25C.

One thing I would mention is that it is a tricky rim when fitting tyres by hand. Prepare for sore thumbs. I guess this is due to the ‘tubeless ready’ nature of the rims.

Graham
 
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