VT Biker

So I am trying to determine the tension Alex R450 rims should be trued up to?

Their website reads like someone Google translated e-mails to the Company inquiring directly of this. Any chance someone here knows what the tension should be?

Thanks,
Brad

Bob Dopolina 

What kind of spokes are you using?

VT Biker

I am using 1.8 mm steel round spokes. Nothing fancy, and easily identified on the Park Tool Tensiometer table.

VT Biker

Thought I would re-fresh this in order to see if anyone can help me with these rims. Psimet?

Bob Dopolina 

What is your weight and what is the purpose of the wheel? Lacing patterns?

VT Biker

Bob,

my weight is 142 pounds.

Front is 3x 28 spoke
Rear is a 3x 32 spoke.

Hubs are Formula (basically wheel set which came with my wife's bike).

Spokes are 1.8mm stainless round.

It is strange - in order to dish it, I need tension on the drive side of 150 kgf (25 on the Park Tool meter), with around a 15 on the Park Tool meter on the non-drive side (around 58 kgf). However, this scares me since that is on the high-end of the tension, and not sure Alex rims were designed to take that. But either I need to drop the tension on the non-drive side significantly (below 40 kgf) if I want a tension closer to 110 kgf on the drive side.

If anything, this makes me wonder whether the spoke length is incorrect on the drive side or non-drive side when the wheels were built, and they over-corrected.

urbanknight

It sounds like Bob will come back a more accurate answer for you, but I find a good general rule for most regular builds (28-36 spokes, no weird lacing patterns, etc.) to be 110kgf for eyeleted rims and 100 kgf for non-eyeleted rims. If you're running 30% on the NDS, something is wrong.

Bob Dopolina 

+1

You've already figured out that 150kgf for butted 1.8 round spokes is too high and that your NDS is too low so that's good. And you have tools.

Do you know what length spokes are in the wheel now?

The ERD of the rim is 598. Do you have the hub dimensions? If not, you can measure the hub like this.

If you have the hub dimensions here's a link to a pretty simple calculator that I've been using for a while with consistent results.

Instead of guessing which spokes are off (I think NDS) it might be easier to calculate and measure.

VT Biker

Wow,

sounds like at this point, I need to detension the entire wheel, and completely start over as if I were building them up. However, the wheel will not dish if I increase the NDS tension and decrease the DS tension.

Question - how low can I go on the NDS? If I need 100kgf on the non-drive side, then I need to lower the tension on the NDS to compensate, or else it will not dish. Have you ever encountered this situation before? If a wheel cannot dish without this disparity in tension, what does this typically mean?

I am not sure these are butted spokes. They are straight-gauge (very cheap wheel build by the manufacturer Marin to reach whatever price point they were going for).

Bob Dopolina 

This wheel was already built?

How are you checking the dish?

VT Biker

Bob,

yes - the wheel came with my wife's bike. It was out of true, and so I went to re-true it. I trued it up, and then when I went to dish it, it was off my probably 15 millimeters. So then I started the process for dishing the rim, resulting in the tension issues on the DS and NDS I am describing now. I am fine dropping the non-drive side tension if I can, since those are not as important as the DS spokes, but there must be a point at which the tension becomes so low as to compromise the wheel integrity.

VT Biker

I am checking the dish using the Park Tool WAG 3 portable dishing devise, setting the screw on top of the nut on either side of the wheel. I believe I am using it correctly...i.e. the screw should contact the nut, and ends of the tool should touch the rim flush on both sides of the wheel.

https://www.mycyclinggear.com/park-to...auge-2008.html

Bob Dopolina 

Ok. You have tools and it sounds like you are using them correctly.

What I would do would be to de-tension the wheel and add washers to the NDS. Then re-tension the wheel bringing the DS up to the 100~110 kgf range with the proper dish. Check the NDS. If the tension is closer between the two sides but still not up to snuff I'd fork out the cash for new NDS spokes 2mm shorter than what are in the wheel now.

Very often, in an effort to save some coin, OE wheels will be built with the same length rear spokes. You may be in that situation. You could always pull a spoke from each side and check.

VT Biker

Bob,

thanks so much for the help with this. A couple of follow-up questions from a newbie here:

A) I imagine I need to take out the spokes from the NDS to add the washers.
B) What are the specific washers you have in mind?


If I could, I would buy you a beer for this help. Saved me a lot of time and frustration. I just purchased that online book everyone recommends, and am going to also start to read that. Zinn's book is too brief to deal with these situations.

Thanks,
Brad

Bob Dopolina 

Brad,

You just need to remove the nipples from the spokes. The washers go inside the rim between the rim and the head of the nipple.

I slide the washer onto an extra spoke in my hand. I stick this spoke into the spoke hole until it is end to end with the spoke inside the rim and then I let the washer slide down the spoke in my hand onto the spoke in the rim.

Then I thread the same spoke into the back of the nipple and insert it into the spoke hole and onto the spoke in the rim. You should be able to push it through so you can grab the other end of the nipple as it protrudes through the rim on the other side. Spin the nipple onto the spoke in the wheel and unthread the spoke in your hand from the backside of the nipple.

Rinse and repeat.

We sell washers here but there are other sources as well and maybe an LBS in your area.

As for the beer maybe we could meet mid-way. Alaska? Northern Japan?

Phantoj

if your rim is in tension, "you're doing it wrong", lolol hehehe...

VT Biker

Bob,

first of all - thanks again for all of the help. So I went home, and completely detensioned the wheel. Then re-trued the wheel, and it dishes within 1 mm, with fairly uniform tension on the drive side, and fairly decent tension on the non-DS. There is about 1 mm at most of difference between the two sides, and I think I can live with that tolerance.

Question however on rim true tolerances. How much radial and how much lateral tolerance do you allow when determining whether a rim is true or not?

urbanknight

To paraphrase Peter White, it depends on how true the rim is. For brand new wheels, most rims should get within .5mm each way and still be within a 10% tension variance. Older rims may be slightly warped or worn and could be further out than that. You'll probably never notice a few mm while riding, but once they start touching the brake pads, that's a problem.

valleycyclist

If the tension is uniform, then it is best to leave it alone with the 1mm variation. Even tension is more important than the wheel being perfectly true.

VT Biker

okay - so I may need to go back. I think my range was around 94 kgp to 131 kgf, with most around the 105 range. Although before I do that, could I get by with this range of tension?

urbanknight

Keep in mind that the range is for each side since the DS and NDS will vary by up to 50%. If you still mean that the drive side is 94-131, then yes I would go back and try again. Remember that when truing a wheel, you often have the choice of 2 or more spokes to make the adjustment with. As I mentioned above, I would consider 110 to be about the max tension. Any more than 120 and you're risking some cracked spoke holes.