Chromed aluminium rims, are they OK?

I'm looking for a new rim for my 408. I've hit a few bumps and the spoke nipples have started to pull through in two places. I am looking for a stronger more durable rim.
The LBS guy recommends I get a dual wall chromed aluminium rim that is used on downhill MTBs.
I am wondering, under normal circumstances the chrome will be harder than the aluminium, so there will be cracking of the chrome, possible crack propagation into the rim and delaminating.
What have they ('they' meaning 'them that make these rims') done to get around this? Are they durable? Does it improve braking (with rim brakes) as my LBS guy says?
When I was a kid, chromed steel wheels were much worse for braking than plain aluminium.

Has anyone used these or know about them?

My bike shop in West Vancouver recommended these double walled rims with heavier spokes. I think
they said that the spoke holes were reinforced with eyelets too, but I don't see that mentioned. Unless
chrome plating is applied very thick and done properly, there is a very good possibility of peeling. I
can't see how it would improve braking. Chrome plating is probably more slippery than machined
aluminum, so I'd think the braking would be worse.

http://www.alexrims.com/product_detail.asp?btn=2&cat=2&id=71

They used thicker than average spokes too, but the size is not mentioned on my bill from the
bike shop.

Not sure bout the chrome part, but yes on the double walled rims, i refuse to lace a hub in a single walled rim anymore.. i have a stack of them i will never use.

Sunrims Rhyno Lite.. or Alexrims DM18 or DM24 are good candidates, the eyelets are all for 14 gauge spokes ( might work with 13 ) but will not fit 12 gauge without being reamed ( I use a round file for sharpening chainsaws to widen them out )

Most/all moddern rims are aluminum, cheap chrome plated steel rims squeal like a slaughtered pig when wet, but any purpose high end rim made for BMS or Downhill use, even if somehow chromed, would be suitable i'm sure.

If the DH guys uses disc brakes I guess it makes sense to chrome them rims for durability's sake. I know theres some very high quality triple wall bmx rims that are chromed aluminum.

having done some chome plating of my own, I know that chrome will not bond with aluminum. You can get other metals to bond, then a few more, and eventualy work up to chrome, but those metals include zink, bras, and copper. none of which are known for striength. Since the chrome plate is just a micro thin layer over other soft metals, its not adding any striength. It is adding weight, though.

Unless it's a show piece, Anodized Aluminum looks chrome-ish.


Sunlite makes some great rims. the Rhyno line is plenty strong. I prefer the MTX downhill rims wityh a welded seam. As others point out, Double wall or nuthin.

ElectricEd said:

I'm looking for a new rim for my 408. I've hit a few bumps and the spoke nipples have started to pull through in two places. I am looking for a stronger more durable rim.
The LBS guy recommends I get a dual wall chromed aluminium rim that is used on downhill MTBs.
I am wondering, under normal circumstances the chrome will be harder than the aluminium, so there will be cracking of the chrome, possible crack propagation into the rim and delaminating.
What have they ('they' meaning 'them that make these rims') done to get around this? Are they durable? Does it improve braking (with rim brakes) as my LBS guy says?
When I was a kid, chromed steel wheels were much worse for braking than plain aluminium.

Click to expand...

You need a rim with a stronger spoke bed that can take more spoke tension without harm. You don't need a downhill rim, although many DH rims meet that description.

Chromed aluminum works better for braking than chromed steel (the aluminum still carries heat away from the surface much better than steel, and the aluminum extrusion provides a more uniform surface for the brake pads to ride on), but for best results it must be combined with a pad designed for use with chrome rims. These are often dark green or blue-green in color. They tend to brake fine when dry, but they are horrible in wet conditions.

Chrome over aluminum eventually peels or flakes in pieces that can cut you if you handle them. Sometimes it peels all the way down to aluminum; sometimes it exposes the nickel plating directly underneath the chrome. In either case it leaves edges that continue to peel and cause braking anomalies in the meantime. In general, chrome plating on rims is best to avoid.

For a really strong rim that doesn't cost much at all, try the Alex DM24. It's similar to the Sun Rhyno Lite, but a little wider and heavier, with a nice thick spoke bed that can take all kinds of tension. It's one of the strongest rims at any price, and you just can't beat the price.
(EDIT to repair URL http://jensonusa.com/store/product/RI308A05-Alex+Dm24+Rim.aspx

If you can find one, the Sun Mammoth and similar Sun BFR are also excellently strong rims, a little heavier and stiffer yet than the Alex DM24. I don't know what the limits of this rim are, but I have not reached them (I have ridden on this rim at weights up to 400 lbs). I think it's out of production, but there are still specimens out there to be had.

Don't make the mistake of using too-thick spokes on your wheels-- this will only result in needless spoke loosening. Spoke breakage is prevented by proper hand building techniques including stress relieving. 14ga spokes or better yet 14-15ga double butted spokes are way more than adequate for our loads and make more reliable and maintenance-free wheels. The strength of the wheel is in the rim, not the spokes.

Chalo

Chalo said:

In general, chrome plating on rims is best to avoid.

For a really strong rim that doesn't cost much at all, try the Alex DM24. It's similar to the Sun Rhyno Lite, but a little wider and heavier, with a nice thick spoke bed that can take all kinds of tension. It's one of the strongest rims at any price, and you just can't beat the price.
http://jensonusa.com/store/product/RI30 ... 4+Rim.aspx

If you can find one, the Sun Mammoth and similar Sun BFR are also excellently strong rims, a little heavier and stiffer yet than the Alex DM24. I don't know what the limits of this rim are, but I have not reached them (I have ridden on this rim at weights up to 400 lbs). I think it's out of production, but there are still specimens out there to be had.

Don't make the mistake of using too-thick spokes on your wheels-- this will only result in needless spoke loosening. Spoke breakage is prevented by proper hand building techniques including stress relieving. 14ga spokes or better yet 14-15ga double butted spokes are way more than adequate for our loads and make more reliable and maintenance-free wheels. The strength of the wheel is in the rim, not the spokes.

Chalo

Click to expand...

Thanks Chalo,
really good info, and thanks to all you others.
It looks like my LBS guy is spinning BS (or just doesn't know) to sell a more expensive but useless rim. It seems like the Alex DM24 is the way to go.
All I have to do now is find a supplier for them down here in Oz.
And thanks for the point about spoke loosening, that's been a problem on the Crystalyte rim which has humungously thick spokes.

Whatever Chalo sez, you can take to the bank or sue me.

Found a supplier for the rims....

http://www.torpedo7.com.au/products/AXRIRW724/title/ALEX-DM24-Rim

I have been riding on the Weinnman DM 30 with my GM 500w at 260lbs total weight for 2K miles with no problems. The ones I have came from Florida and I was told are one of the few still made in the USA although I see no sticker saying where they were made. These have been pre-drilled for the 12 gauge spokes and were comparable to the Rhyno lites in price. They are a bit wider like I wanted and a satin aluminum color. They are pinned not welded and machined like the Rhynos. Inexpensive and take a beating for sure. I got near the same rim from Seattle and it had a very poor finish as well as not drilled for the larger spokes so it does matter where they come from. They have been through allot and held up very well. Pic is a new one.

bought them here.

http://www.greshambike.com/info.html

adrian_sm said:

Found a supplier for the rims....

http://www.torpedo7.com.au/products/AXRIRW724/title/ALEX-DM24-Rim

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Careful-- that's a 24" rim (ISO 507). If that's what you want, great, but the normal MTB size is 26" (ISO 559). Maybe that supplier stocks both.

My earlier URL got munged. The correct one is http://jensonusa.com/store/product/RI308A05-Alex+Dm24+Rim.aspx

I know it may not help you in Oz, but it's an excellent price (USD $21) for anyone who can get a reasonable shipping rate. Pedicab.com has the 48 hole kind for $25.

Chalo

Thanks again Chalo,

BTW, is that a live cat or a hat?
If it's a hat it won't catch a rat,
but if it's alive
then don't take a dive
because that kitten
will scratch your chin!

Down here in Oz there's a bloke that sells feral cat hats. They are as soft as the real thing and cost nothing to feed! :wink:

ElectricEd said:

BTW, is that a live cat or a hat?

Click to expand...

He's both, at least from time to time.