Touring - Two different sized rims?

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View Full Version : Two different sized rims?


geonjorjany
06-25-10, 09:27 AM
Okay, so here's the scenario. I currently have a LHT with the stock 26" Alex Adventurer rims on both of the wheels. Before my tour this fall I want to put a dynamo hub (SON28) on the front wheel to power a headlight, taillight, and something to charge electronics (e-werk maybe). I was just going to buy the hub and have my LBS build a wheel using the new hub, new spokes and the old rim (only a few hundred miles on it). My LBS said he didn't recommend using the old rim, but it may not be a problem.

So comparing the price that my LBS wanted to build the new wheel with one built by Peter White (peterwhitecycles.com) I figured it might just be better to buy a full wheel from Peter White. So here's my question for you: will riding with two different, though similar, rims pose any problems? If so should I just buy the hub and have my LBS build me a wheel? If I should get a wheel built by Peter, any recommendations on what rim to go with?

Thanks for any input. I try to find the answers to most of my questions by lurking and searching here, but sometimes specifics just require a post. If this post would be more suitable for the Bicycle Mechanics thread I apologize, it just seemed more appropriate here since I'll be riding with a loaded rig among other things.


khanom
06-25-10, 09:32 AM
It's really not an issue. As long as both rims accommodate the tires you want, you're fine. One very minor consideration is that you may need two different sized spoke wrenches.... maybe.

rhm
06-25-10, 09:40 AM
Yeah, I don't think it matters much.

Curious, though... why didn't the shop want to use your existing rim? Is he trying to sell you a new rim, or is there a genuine concern about the Alex Adventurer? If the latter, does he want you to replace the rear one as well?

By the way, I would recommend you build the wheel yourself. While not exactly easy, the first time you do it, it's not rocket science; and it's a lot of fun. And what a way to get to know your bike a little more intimately!


dcrowell
06-25-10, 09:41 AM
You don't even need the same size tires. :)

I ride with a guy who runs a wider tire on the front of his LHT. The tire is a bit wide for the rear, but fits in the front. He likes to ride gravel, so having the extra rubber up front is helpful.

Ruffinit
06-25-10, 09:45 AM
+1 to khannom
You could just have a second set of wheels built and keep this set for a different tire/wheel combo or winter wheelset. IF your current wheelset only has a few hundred miles on it, have them use the rim anyway. The deal is that your LBS has no knowledge of that rim and probably will not warrant it if you use it. Plenty of hubs/wheels/spokes have been reused for building wheels that are perfectly good for extended use. They're being cautious on your behalf. If you want to save a little expense, delace the wheel yourself and deliver them the rim and the new hub and just tell them to build it up.
OR you could mailorder (internet order) the exact rim that you have on the front of your bike, deliver it and the new hub to the LBS and keep your original. This is what I would do, but I build my own anyway.

furballi
06-25-10, 10:32 AM
Go to a better shop, or find a competent wheel builder to mate the new hub with the old rim.

If you have $ to burn, then get a new hub and rim. Use the OEM wheel for backup. I prefer the Mavic A319 over the stock Alex...more durable rim. Be sure to pick a SON 28 with at least 32 hole. 36 hole is best for touring.

There is no way you can build a high quality rim on the 1st try. Too many tricks of the trade to learn.

geonjorjany
06-25-10, 11:21 AM
The guy at the shop suggested not reusing the rim because, he said, putting the rim under tension, then releasing the tension, and then putting it under tension again would weaken it. He didn't seem to be concerned with the brand or type of rim. I really like the idea of building the wheel up myself. I'm going to do some research and see if that's something I may be comfortable with doing (or confident enough doing to be comfortable riding on it). If not, I'm still undecided on whether to buy built or have the LBS build it. I'll ponder over things for a bit before I decide. Thanks for the advice everyone. Any more thoughts on things are welcome.

furballi
06-25-10, 11:52 AM
That's BS. He's a mechanic, not an engineer.

Below the yield strength all deformation is recoverable, and the material will return to its initial shape when the load is removed.

http://en.wikipedia.org/wiki/Tensile_strength

rhm
06-25-10, 11:57 AM
You can totally build the wheel yourself. It's a bit more of a skill to get it perfectly true, centered, and tensioned; some would take it to the bike shop for this part of the job (I wouldn't).


That's BS. He's a mechanic, not an engineer.

+1.

Well, maybe I'd have said he's a salesman, not an engineer... but no point in arguing semantics.

_____

Oh, by the way, you don't really mean two different sized rims, right? They'd be the same size, just different brands/models/style. They might even be different widths; but I assume both would be 26" rims.

Shimagnolo
06-25-10, 12:07 PM
The guy at the shop suggested not reusing the rim because, he said, putting the rim under tension, then releasing the tension, and then putting it under tension again would weaken it.

That is what happens to every spoke as the wheel rotates with a load on it.:twitchy:

LHT in Madison
06-26-10, 06:05 AM
Having an extra wheel or pair of wheels is not a bad idea either. After I built up my LHT I learned of a really cheap set of wheels on sale and bought them. I did not need them but they were too cheap to pass up. The high quality wheels have my 700cX37mm touring tires installed and the cheap set has the 700cX28mm high pressure supple casing smooth tread fast tires.

A lot of people ride with different rims if one rim fails. It generally is not a problem as long as rim width is similar so that the same tires can be used front and rear.

LeeG
06-26-10, 09:30 AM
if you have the money to buy a Son hub then the price of Whites build is worth it and you can keep the spare wheel. The Alex Adventurer is a heavy rim and for front wheel use you could get away with a lighter one. Go ahead and get a 36hole Dyad on the Son. If you're considering building up a front wheel on the SON hub by yourself then go ahead and get a new rim, it's not going to save you much money using the old Alex rim and you'd be losing a whole wheel in the process. I've got a 32 hole 26" Dyad rim on a Son hub for the front wheel and a 36hole Rhynolite rear wheel.

geonjorjany
06-27-10, 04:38 AM
Thanks for all the advice. I think I'll be getting a full wheel built by Peter, and then I'll have the other as a spare, and maybe I'll even take it apart and build it back up myself a few times to get some practice at that and see how it goes. Now I'm just trying to figure out what rim to have Peter put on the new wheel. I'm thinking Velocity Aeroheat, based on what I've read while searching through old threads on here. Thanks again for the input everyone.

jtgotsjets
06-27-10, 08:26 AM
That's BS. He's a mechanic, not an engineer.

Below the yield strength all deformation is recoverable, and the material will return to its initial shape when the load is removed.

http://en.wikipedia.org/wiki/Tensile_strength

Dudes, chill out. The bike shop not wanting to re-use a rim when building a wheel has nothing to do with physics and everything to do with liability. It's much easier for them to just say "We will not build you a wheel with used spokes or rims" then to say "We will make an informed decision whether or not we can in good conscience build your wheel with an old rim. Additionally, we accept no responsibility should any injuries arise as a result of said wheel exploding."