Hello,

I have two wheels with Velocity Aerohead rims, with Sapim aero spokes and White Industries H2 hubs. Spoke count is 24/28.

I would like to keep the hubs and spokes, but swap out the rims for something else, such as the Boyd Altamont Lite.

I was wondering if this is something I should attempt to do myself? I know my way around a bike, but have no experience building, or even truing wheels. I am willing to learn though. I don't own a truing stand, but I read I can just use the bike as a truing stand?

What are some things I should look out for/know before I buy new rims?

I read somewhere I could just lace up the wheel, and have my LBS true it properly for me? Is this a viable option? Or should I just take the whole thing to my LBS and have them build it up for me?

Thanks!

If you want to keep the spokes, you will need to find replacement rims with the same "effective rim diameter" (ERD) as your Velocity Aeroheads and, of course, the same spoke count. If the ERD of the rims you choose is different you will need different length spokes.

A good technique to replace a rim is to tape the new rim right next to the old one. Then de-tension the old wheel and move the spokes over to the new rim one by one.

Could I reuse the spokes if the ERD of the old rim is 598mm and the new one is 602mm? Can I account for that 4mm variation you think?

Thanks, that is a great suggestion! I found some more useful information here: Building Bicycle Wheels Wheelbuilding

[MENTION=38165]HillRider[/MENTION] made a good point about ERD. The ERD needs to be the same if you want to re-use spokes. If the new rim has a different ERD, you'll need spokes of a different length.


Wheelbuilding isn't that difficult. Find a guide to help you (plenty online) and follow the directions scrupulously.

You'll need a real truing stand to finish the wheel build, and you might want a spoke tensiometer.

I've built a couple wheel sets. I do the lacing and preliminary tension at home, and then I finish it in a truing stand at the shop or the bike co-op.

You could probably lace the spokes yourself and have the shop finish the build.
But, I'd contact the shop first to see if they're OK with that. They may prefer to do it all themselves, because they'd hate for you to bring in an improperly laced wheel that would take them LONGER to fix. Most shops build lots of wheels, and then can do it pretty quickly.

There is some room for judgement/preference/fudging WRT spoke length, so it depends on where your current spokes ends in the nipples.
If your current build is kinda long, then 2 mm shorter can be OK.
If your current build is mid-range, then 2 mm short will leave a questionable build.
If your current build is kinda short, then 2 mm short will leave an outright poor build.

Unless you tinker around with longer nipples, a method usually frowned upon.

In general, if you can true and tension a wheel, swapping rims is the easiest next step toward building your own from scratch.



That's 2 mm difference in spoke length, about the outer limit for my comfort. Can you find a rim with and ERD closer to the old one?


Alternatively, you might want to build an entirely new rim for racing (I presume) and keep the old one for training.

Thanks guys. I understand I should stick with same ERD if possible.

Would it be easier to go for a smaller ERD? Let's say from 598 to 594? Or does that also pose problems?

Also, the rear wheel is a Velocity Aerohead O/C, meaning that the rim is off-center, or not symmetrical. Does that mean the spokes on one side are shorter / longer than on the other side? Does that mean I need another O/C rim if I want to reuse the spokes?

Thanks!

That too depends on what your current build is like.
With DT spokes and nipples you have about 2 mm overshoot over the top of the nipple before you run out of threads. Running out of threads is bad, since that means you can't tension properly.

Slightly longer is better than shorter.
You can't stretch a spoke, but you can fit washers to the nipples to sorta stretch the ERD.
Or drill out a couple of turns of thread to allow for more overshoot.

Same sort of issues; anything away from a match is not good; and quickly gets into will not work.

Before asking any of these questions, take the tire, tube and rim tape off and look at where the end of the spokes are in the nipples. Then you will know what you have, tell us, and get some useful opinions.

Very small effect, less than 0.5mm; almost never taken into consideration.

Since the rim doesn't sit centered between the hub flanges on wheels with external gears, it's very common for wheels to have different spoke lengths on DriveSide(DS) and NDS.

With an OC rim the nipple holes end up a little closer to flange center. Possibly, but not guaranteed, to allow the same length spokes to be used.

I recommend you remove one spoke from each side and measure what you got to be able to do a good prediction WRT spoke reuse.

Thanks guys.

I am now looking at the Velocity A23 rims, which have an ERD of 601mm. This should work hopefully for replacing both the Aerohead at 602mm and the Aerohead OC at 598mm.

I will take out the rim tape and have a look at the spokes. Maybe take some pictures and post here.

I have been looking at this thread and my curiosity has been piqued. Are your current rims worn out? If not, what do you hope to gain by changing them?

Like so much.... IT DEPENDS, and your existing wheel will give you the answer.

If the spokes barely come to the tops of the nipples, you don't have 4mm to give up (minimum length = 2-3mm below the tops of the nipples). OTOH if the spokes currently stick up 2mm or so, you're in like Flynn.

maartendc, The two possible problems with using the same spokes for rims with a different ERD is running out of thread before the spokes can be properly tensioned or not having enough thread captured by the nipple to support the load.

You have a much greater chance of success using your present spokes with a 1 mm difference than a 4 mm difference. No guarantees tho'.

Brad

Thanks for all the helpful replies so far!

Okay so i have taken some photos, the first is the wheel with smaller ERD, you can see the spokes are 'deeper' into the rim. The other one has a larger ERD, so more of the spoke is showing.

The ERDs are 598 and 602 mm respectively. I think i have settled on using DT Swiss RR440 rims, which have an ERD of 599, so they should fall nicely in between both ERDs.

The wheel with larger ERD has the spokes barely sticking throuh the nipples when I look at them from under the rim tape. (See photo) So i think there should be plenty of play to go from 602 to 599mm there, because the spokes are on the shorter side. I dont think i should run out of thread.

Any expert opinions on this?
Any other things I should know going with these DT Swiss rims?
Thanks!



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"barely sticking throuh the nipple"

What part of the nipple?
Where's the screw driver slot in relation to the spoke end? That's the info needed.

I'd have some of these on hand for the wheel with the larger ERD rim just in case.

With spokes ending at the slot of alloy nipples, more than 2mm additional ERD is likely to break nipples.

The spoke end is sticking out about 0.5-1mm from the screw driver slot. So not much at all. So I should have some play to use these spokes with a smaller ERD right?

Nipple washers? Thanks, thats a good tip! I can always use these to add some extra ERD!

From flush, you have about 1.5-1.75ish MM before the nipples run out of thread.
That's just grabbing an old spoke & new DT nipple.

That would give about 3mm more ERD, assuming that NONE of your nipples are more than that. Not real likely, but possible.

For your smaller ERD wheel after you build if you don't thread into the nipple enough and don't like it DT Swiss nipples have longer threads for longer nipples. Sapm nipples do not have longer threads they have longer barrels/flats.

Here is a good explination

Here is a photo from Roger Musson's wheel book of DT-Swiss nipples: