Spoke length for Aerohead (and other) off center rims?

[oliver1850]

Seems to me that the OC rim would take spokes 1 or 2 mm longer on the drive side and 1 or 2 mm shorter on the left. When I ran a 32 hole Aerohead, 3 cross, 5800 hub through the prowheelbuilder calculator it gave me 292 L, 290 R for the OC and 294 L, 292 R for the on center rim. Is there something different about the OC rim other than the offset drilling that would account for both spokes being shorter on the OC? I have some Ritchey offset rims that I'll probably build at some point. Wondered if there's a more or less standard compensation for spoke length with offset rims. I realize that offset could vary, but doubt there's much difference in offset with 20 mm-ish road rims.

[Kontact]

Originally Posted by oliver1850

Seems to me that the OC rim would take spokes 1 or 2 mm longer on the drive side and 1 or 2 mm shorter on the left. When I ran a 32 hole Aerohead, 3 cross, 5800 hub through the prowheelbuilder calculator it gave me 292 L, 290 R for the OC and 294 L, 292 R for the on center rim. Is there something different about the OC rim other than the offset drilling that would account for both spokes being shorter on the OC? I have some Ritchey offset rims that I'll probably build at some point. Wondered if there's a more or less standard compensation for spoke length with offset rims. I realize that offset could vary, but doubt there's much difference in offset with 20 mm-ish road rims.

Did both rims have an identical ERDs? I'm betting not.

Just playing with a spoke calculator, changing the spoke offset by 5mm only yields a .5mm change in spoke length, in the direction you would expect. So I think the ERDs are different for the rims you're comparing.

[oldpotatoe]

Originally Posted by oliver1850

Seems to me that the OC rim would take spokes 1 or 2 mm longer on the drive side and 1 or 2 mm shorter on the left. When I ran a 32 hole Aerohead, 3 cross, 5800 hub through the prowheelbuilder calculator it gave me 292 L, 290 R for the OC and 294 L, 292 R for the on center rim. Is there something different about the OC rim other than the offset drilling that would account for both spokes being shorter on the OC? I have some Ritchey offset rims that I'll probably build at some point. Wondered if there's a more or less standard compensation for spoke length with offset rims. I realize that offset could vary, but doubt there's much difference in offset with 20 mm-ish road rims.

I think different ERDs also. I calc and ‘normally’, non drive side is 2mm longer, on OC, I make it 1mm longer, seems to work with spoke end about at end of nipple when done.

[Mark McM]

Rear hub left and right flange offsets differ by 15 - 20 mm, but that only results in a 1 or 2 mm difference in spoke length. Due to limits of rim width, off-center rim spoke holes can only be offset by a few millimeters. Therefore, the difference in spoke lengths caused by the spoke hole offset will generally be just a fraction of a millimeter (all else being the same). The biggest variable in spoke length (especially for crossed spoke lacing) is ERD.

[oliver1850]

Sounds like you are all pretty much in agreement with what I was expecting. I don't have the rims in hand yet. I was going off the information on the prowheelbuilder site for ERD, but didn't look beyond the spoke lengths it spit out. After going back and looking at the numbers, they give an ERD of 598 for the OC, and 602 for the Aerohead. Wasn't expecting that and not sure why it should be so, but if accurate resolves my question. I should have payed more attention when using the calculator. Now wondering about the Ritcheys, but I will take a conservative approach to lengthening the drive side/shortening the left from whatever I come up with for a rim with centered drilling.

[saab2000]

Not to derail the spoke length conversation, but there are better asymmetrical rims available today than the Aerohead. Today's are made wider, which is almost universally thought to be better and with better alloys than Velocity rims.

I would shop around.

[oldpotatoe]

Originally Posted by saab2000

Not to derail the spoke length conversation, but there are better asymmetrical rims available today than the Aerohead. Today's are made wider, which is almost universally thought to be better and with better alloys than Velocity rims.

I would shop around.

Velocity no longer makes the 'Aerohead' in OC..not sure when they stopped or if that model is US or Australian made. A23 a great rim, have built many, including the US made ones.

[ergott]

After measuring a collection of those rims I get 599.5mm for the OC and 603 for the front. There was plenty of sample variation due to die wear for those so I would re measure your rims before building. It will save you from potential headaches.

[ultraman6970]

https://leonard.io/edd/


put velocity in the rim and press enter, then check out the OC rims.

[oliver1850]

Originally Posted by ergott

After measuring a collection of those rims I get 599.5mm for the OC and 603 for the front. There was plenty of sample variation due to die wear for those so I would re measure your rims before building. It will save you from potential headaches.

Thanks Eric. I measured my pair at 602.6 front and just under 600 for the OC rear. It's always nice to have someone else come up with a measurement that's close to what I got. Built the front last night: 28 hole, 2X, DT 14/15, AL nipples, Zipp hub. Waiting on the 5800 rear hub to show but it will be 32 hole, 3X, DT 14/15, brass nipples.

[oldpotatoe]

Originally Posted by oliver1850

Thanks Eric. I measured my pair at 602.6 front and just under 600 for the OC rear. It's always nice to have someone else come up with a measurement that's close to what I got. Built the front last night: 28 hole, 2X, DT 14/15, AL nipples, Zipp hub. Waiting on the 5800 rear hub to show but it will be 32 hole, 3X, DT 14/15, brass nipples.

I used 602 for the front and 600mm for the rear..from my well used and much scribbled in, Wheelsmith spoke calc book...

[oliver1850]

Thanks Peter. I wish I was organized enough to keep track of all the wheels I build. Seldom build the same rim/hub combination though. Rear hub arrived today but I'm still waiting on spokes for one side.